JP2005189323A - Projector and control method for projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector realizing improvement in convenience by restraining the rise of internal temperature, and a control method for the projector. <P>SOLUTION: The projector is equipped with a light source driving control part 722 controlling to intermittently turn on a light source device 2, a temperature detection sensor 20 arranged near the light source device 2 and detecting the temperature of the light source device 2. The control part 722 is equipped with a duty ratio control part 722A performing the control of a duty ratio for intermittently turning on the light source device 2 at a prescribed duty ratio, and a control state switching part 722B switching a control state by the control part 722A. The switching part 722B compares detected temperature detected by the sensor 20 with the prescribed 1st temperature threshold and allows the control part 722A to perform the restraining control of the duty ratio for shortening turn-on time per unit time in intermittently turning on the light source device 2 when the detected temperature exceeds the 1st temperature threshold. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a projector and a projector control method.

Conventionally, a light source device, an electro-optical device that modulates a light beam emitted from the light source device according to image information to form an optical image, and a projection optical device that enlarges and projects the optical image formed by the electro-optical device Is known (see, for example, Patent Document 1).
In such a projector, when used for a long time, the temperature inside the projector tends to increase due to heat generated from the light source device and heat generated in the electro-optical device by absorbing a part of the light beam emitted from the light source device. . The projector described in Patent Document 1 includes a control unit, and the control unit detects the temperature inside the projector and stops driving the projector when the temperature rises and is determined to be in an abnormal state. That is, control to turn off the power is performed.

JP-A-9-130700

However, in the projector described in Patent Document 1, since the power is turned off when the internal temperature becomes abnormal, the projection screen suddenly disappears, which is inconvenient for the user.
Therefore, it is desired to develop a projector that can suppress an increase in internal temperature and improve convenience.

  An object of the present invention is to provide a projector capable of suppressing an increase in internal temperature and improving convenience, and a projector control method.

  The projector of the present invention forms an optical image by performing light modulation by changing the light transmittance or light reflectance of the light source device and the light beam emitted from the light source device according to the gradation level of the image information. A light source drive control unit that controls intermittent lighting of the light source device, and a light source device that includes a projection optical device that magnifies and projects an optical image formed by the electro-optical device. A temperature detection unit disposed in the vicinity of the light source device for detecting the temperature of the light source device, and the light source drive control unit performs a duty ratio control for intermittently lighting the light source device at a predetermined duty ratio; and A control state switching unit that switches a control state by the duty ratio control unit, wherein the control state switching unit includes a detected temperature detected by the temperature detection unit and a predetermined first temperature threshold value. When the detected temperature exceeds the first temperature threshold, the duty ratio control unit performs duty ratio suppression control to shorten the lighting time per unit time when the light source device is intermittently lit. It is characterized by making it.

Here, as an electro-optical device, either a type that performs light modulation by transmitting a light beam emitted from a light source device or a type that performs light modulation by reflecting a light beam emitted from a light source device. May be adopted.
The duty ratio is a ratio between a lighting time per unit time when the light source device is intermittently turned on and a turn-off time per unit time.
Further, in the duty ratio control by the duty ratio control unit, before the detected temperature exceeds the first temperature threshold, for example, a control for intermittently lighting the light source device at a predetermined duty ratio may be performed. Or you may implement control which lengthens the lighting time per unit time at the time of making a light source device light intermittently according to a raise of detected temperature.
Furthermore, in the duty ratio suppression control by the duty ratio control unit, for example, even when the light source device is intermittently lit continuously at a predetermined duty ratio that shortens the lighting time when the light source device is intermittently lit. Alternatively, depending on the detected temperature, control may be performed to appropriately turn on the light source device by appropriately changing a predetermined duty ratio that shortens the lighting time when the light source device is turned on intermittently.
In the present invention, the light source drive control unit constituting the projector includes a duty ratio control unit and a control state switching unit. The control state switching unit causes the duty ratio control unit to perform duty ratio suppression control of the light source device when the detected temperature detected by the temperature detection unit exceeds a predetermined first temperature threshold. As a result, the lighting time per unit time of the light source device is shortened, the amount of heat generated by the light source device can be reduced, and the temperature of the light source device can be reduced. Therefore, the temperature of the light source device can be made equal to or lower than the first temperature threshold, and the temperature rise inside the projector can be suppressed. This also prevents the projector's internal temperature from becoming too high and causing an abnormal state, and there is no need to perform control to turn off the power when the internal temperature becomes abnormal. Since it does not disappear, the convenience of the projector can be improved.

In the projector according to the aspect of the invention, the control state switching unit compares the detected temperature detected by the temperature detection unit with a predetermined second temperature threshold value, and the control temperature switching unit changes the detection temperature until the detected temperature becomes equal to or lower than the second temperature threshold value. It is preferable to cause the duty ratio control unit to perform duty ratio suppression control.
In the present invention, the control state switching unit causes the duty ratio control unit to perform duty ratio suppression control of the light source device until the detected temperature detected by the temperature detection unit becomes equal to or lower than the second temperature threshold. Thus, for example, if the control is performed so that the duty ratio suppression control is returned to the normal duty ratio control after the detected temperature becomes equal to or lower than the second temperature threshold, the temperature that has a small influence on the temperature rise inside the projector, For example, after reaching the second temperature threshold, the luminance of the light source device can be increased and an optical image with good visibility can be projected.

In the projector according to the aspect of the invention, the duty ratio control unit may be configured such that the detected temperature detected by the temperature detecting unit exceeds the first temperature threshold or after the detected temperature becomes equal to or lower than the second temperature threshold. It is preferable to implement duty ratio increase control for increasing the lighting time per unit time when the light source device is intermittently lit according to the rise in the detected temperature.
By the way, when a light-emitting diode element is employed as the light source device, for example, the temperature of the light-emitting diode element itself increases as the driving time of the light-emitting diode element elapses. The light emitting diode element has a characteristic that the luminance decreases as the temperature increases. Therefore, for example, when a light-emitting diode element is used as the light source device, the luminance decreases with the passage of the driving time of the light source device, and it is difficult to project an optical image with good visibility.
In the present invention, the duty ratio control unit performs duty ratio increase control before the detected temperature detected by the temperature detecting unit exceeds the first temperature threshold or after the detected temperature falls below the second temperature threshold. carry out. As a result, even when a light-emitting diode element, for example, is used as the light source device, the lighting time per unit time of the light source device is lengthened, thereby avoiding a decrease in luminance as the light source device drive time elapses. And an optical image with good visibility can be projected.

In the projector according to the aspect of the invention, the duty ratio control unit intermittently lights the light source device at a predetermined duty ratio that shortens the lighting time per unit time when the duty ratio suppression control is performed, and causes the temperature detection unit to It is preferable that the predetermined duty ratio is changed so as to increase the lighting time per unit time in accordance with the decrease in the detected temperature detected, and the light source device is intermittently lit with the changed duty ratio.
In the present invention, when performing duty ratio suppression control, the duty ratio control unit temporarily turns on the light source device at a predetermined duty ratio that shortens the lighting time per unit time, and then detects the temperature detection unit. The predetermined duty ratio is changed so as to increase the lighting time per unit time in accordance with the decrease in the detected temperature, and the light source device is intermittently lit with the changed duty ratio. As a result, even when the duty ratio suppression control of the light source device is being performed, the luminance of the light source device can be gradually increased, and an optical image with good visibility can be projected more quickly. .

In the projector according to the aspect of the invention, the light source device includes a plurality of light sources that can emit a plurality of color lights, and the temperature detection unit includes a plurality of light source devices corresponding to the plurality of light source devices. Each duty ratio at the time of intermittent lighting is set to a predetermined ratio, and the duty ratio control unit performs a hue duty ratio control for controlling intermittent lighting of the plurality of light source devices at each duty ratio set to the predetermined ratio It is preferable to implement.
In the present invention, the light source device includes a plurality of light sources capable of emitting a plurality of color lights. Moreover, the temperature detection part is comprised by two or more corresponding to several light source devices. And a duty ratio control part implements hue duty ratio control of a plurality of light source devices with each duty ratio set as a predetermined ratio. Thereby, a plurality of light source devices each configured to emit a plurality of color lights are adopted, and for example, even when the above-described duty ratio suppression control or duty ratio increase control of a plurality of light source devices is performed, Each light source device can be intermittently lit so as not to always change the hue of each color light emitted from each light source device.

In the projector according to the aspect of the invention, the light source device includes a plurality of light sources that can emit a plurality of color lights, and the temperature detection unit includes a plurality of light source devices corresponding to the plurality of light source devices. Each duty ratio at the time of intermittent lighting is set at a predetermined ratio, and the duty ratio control unit performs a hue duty ratio control for controlling intermittent lighting of the plurality of light source devices at each duty ratio set at the predetermined ratio The control state switching unit performs the hue duty ratio control by the duty ratio control unit based on the plurality of detected temperatures detected by the plurality of temperature detection units, the set predetermined ratio. It is preferable to switch to independent duty ratio control in which the plurality of light source devices are controlled to be intermittently lit at each independent duty ratio.
In the present invention, the light source device includes a plurality of light sources capable of emitting a plurality of color lights. Moreover, the temperature detection part is comprised by two or more corresponding to several light source devices. And a duty ratio control part implements hue duty ratio control of a plurality of light source devices with each duty ratio set as a predetermined ratio. Thereby, a plurality of light source devices each configured to emit a plurality of color lights are adopted, and for example, even when the above-described duty ratio suppression control or duty ratio increase control of a plurality of light source devices is performed, Intermittent lighting control of a plurality of light source devices can be performed so as not to change the hue of each color light emitted from each light source device.
Here, for example, when only the hue duty ratio control is performed by the duty ratio control unit, the duty ratio suppression control of the light source device is performed corresponding to at least one of the detected temperatures. In this case, the light source device having no thermal problem also performs duty ratio suppression control, and the overall luminance when the color lights emitted from the respective light source devices are combined is lowered.
In the present invention, the control state switching unit switches the hue duty ratio control by the duty ratio control unit to the independent duty ratio control based on the plurality of detected temperatures detected by the plurality of temperature detection units. This makes it possible to suppress a decrease in luminance in the case described above.

In the projector according to the aspect of the invention, when the detected temperature of at least one of the plurality of detected temperatures detected by the plurality of temperature detecting units exceeds the first temperature threshold, the control state switching unit The hue duty ratio control by the control unit is switched to the independent duty ratio control, and the duty ratio suppression control of only the light source device corresponding to the detected temperature of the at least one of the plurality of light source devices is applied to the duty ratio control unit. It is preferable to carry out.
In the present invention, the control state switching unit includes the hue duty ratio by the duty ratio control unit when the detected temperature of at least one of the plurality of detected temperatures detected by the plurality of temperature detection units exceeds the first temperature threshold. Switch control to independent duty ratio control. The duty ratio control unit performs duty ratio suppression control only for the light source device corresponding to the detected temperature among the plurality of light source devices. Thus, when performing independent duty ratio control, for example, duty ratio suppression control is performed only for the light source device corresponding to the detected temperature of at least one of the plurality of light source devices, and other light source devices are set to normal If configured to perform duty ratio control, the brightness of the light source device that is not thermally problematic is ensured, and the decrease in the overall brightness when the color lights emitted from the respective light source devices are combined is suppressed. Is possible.

In the projector according to the aspect of the invention, when the duty ratio control unit performs the duty ratio suppression control, the light source device is intermittently turned on at a predetermined duty ratio that shortens the lighting time per unit time, and the temperature detecting unit The predetermined duty ratio is changed so as to lengthen the lighting time per unit time according to a decrease in the detected temperature detected in this manner, the light source device is intermittently lit with the changed duty ratio, and the control state switching unit When the independent duty ratio control is performed by the duty ratio control unit, the duty ratio of the light source device corresponding to the at least one detected temperature is compared with a predetermined duty ratio threshold, and the duty ratio is When the duty ratio threshold is exceeded, the independent duty ratio control by the duty ratio control unit is changed to the hue duty. It is preferable to switch to the control.
Here, the duty ratio is a lighting time per unit time with respect to a turn-off time per unit time when the light source device is intermittently turned on. That is, the case where the duty ratio exceeds the duty ratio threshold means that the lighting time per unit time is longer than the lighting time per unit time set as the predetermined threshold.
In the present invention, when performing duty ratio suppression control, the duty ratio control unit temporarily turns on the light source device at a predetermined duty ratio that shortens the lighting time per unit time, and then detects the temperature detection unit. The predetermined duty ratio is changed so as to increase the lighting time per unit time in accordance with the decrease in the detected temperature, and the light source device is intermittently lit with the changed duty ratio. As a result, even when the duty ratio suppression control of the light source device is being performed, the luminance of the light source device can be gradually increased, and an optical image with good visibility can be projected more quickly. .
In addition, the control state switching unit performs duty when the duty ratio of the light source device corresponding to at least one of the detected temperatures exceeds a predetermined duty ratio threshold when the independent duty ratio control is performed by the duty ratio control unit. The independent duty ratio control by the ratio control unit is switched to the hue duty ratio control. As a result, after the luminance of the light source device corresponding to the at least one of the detected temperatures becomes a luminance that has little influence on the decrease in the luminance of the projected image, the hue duty ratio control is performed, whereby a predetermined luminance value is obtained. And an optical image having a good color can be projected.

The projector according to the aspect of the invention includes an electro-optical device drive control unit that drives and controls the electro-optical device, and the electro-optical device drive control unit performs a predetermined process on the image information to obtain a gradation level of the image information, And a characteristic changing unit that changes a gradation-light transmittance characteristic or a gradation-light reflectance characteristic in light transmittance or light reflectance of the electro-optical device, and the characteristic changing unit is configured to detect the temperature. A lower limit value of the light transmittance or light reflectance of the electro-optical device is set based on the temperature detected by the unit, the set lower limit value, and the light transmittance or light reflectance of the electro-optical device It is preferable to change the gradation-light transmittance characteristic or the gradation-light reflectance characteristic based on the highest value.
Here, the lower limit value of the light transmittance or light reflectance of the electro-optical device is set, and the gradation-light is based on the set lower limit value and the highest value of the light transmittance or light reflectance of the electro-optical device. Changing the transmittance characteristic or the gradation-light reflectance characteristic means, for example, performing a gradation conversion process on the image information, and changing the light transmittance or light reflectance of the electro-optical device in the low gradation region of the image information. A change process can be adopted. In addition to this process, a predetermined offset voltage is added to the driving voltage for driving the electro-optical device, and the driving voltage applied to the electro-optical device is shifted to the high voltage side, thereby reducing the lower order of the image information. You may employ | adopt the process which changes the light transmittance or light reflectivity of the electro-optical apparatus in an adjustment | control area | region.
In the present invention, the electro-optical device drive control unit constituting the projector includes a characteristic changing unit. The characteristic changing unit sets the lower limit value of the light transmittance or light reflectance of the electro-optical device based on the detected temperature detected by the temperature detecting unit, and sets the lower limit value and the electro-optical device. The gradation-light transmittance characteristic or the gradation-light reflectance characteristic is changed based on the maximum value of the light transmittance or the light reflectance. Accordingly, based on the detected temperature detected by the temperature detection unit, for example, gradation conversion processing is performed on the image information, and the light transmittance or light reflection of the electro-optical device in the low gradation region of the image information is performed. By changing the gradation-light transmittance characteristic or gradation-light reflectance characteristic in the electro-optical device by improving the rate, the luminous flux absorbed by the electro-optical device is reduced, and the heat generation amount of the electro-optical device is reduced. Can be made. Therefore, the configuration including both the light source drive control unit and the electro-optical device drive control unit makes it possible to reduce the amount of heat generated by both the light source device and the electro-optical device, thereby effectively increasing the temperature inside the projector. Can be avoided.
Further, even when a light emitting diode element is employed as the light source device, for example, according to the temperature rise of the light source device with the lapse of the driving time of the light source device, that is, according to the decrease in luminance of the light source device. If the characteristic changing unit controls the gradation-light transmittance characteristic or the gradation-light reflectance characteristic to change, the light transmittance or light reflection of the electro-optical device according to the decrease in the luminance of the light source device. By improving the rate, it is possible to suppress a decrease in luminance of the optical image.

In the projector according to the aspect of the invention, when the duty ratio suppression control of the light source device is performed by the light source drive control unit, the characteristic change unit is configured to perform the gradation-based on the temperature detected by the temperature detection unit. It is preferable to change the light transmittance characteristic or the gradation-light reflectance characteristic.
In the present invention, the characteristic changing unit is configured to perform gradation-light transmittance characteristics or gradation based on the temperature detected by the temperature detection unit when the duty ratio suppression control of the light source device is performed by the light source drive control unit. -Change the light reflectance characteristics. As a result, the duty ratio suppression control of the light source device is performed, and when the light source device is intermittently turned on, the lighting time per unit time is shortened, and the luminance of the light source device is reduced. By changing the rate characteristic or the gradation-light reflectance characteristic, it is possible to effectively suppress the decrease in the luminance of the optical image.

  The projector of the present invention forms an optical image by performing light modulation by changing the light transmittance or light reflectance of the light source device and the light beam emitted from the light source device according to the gradation level of the image information. An electro-optical device, and a projection optical device that magnifies and projects an optical image formed by the electro-optical device, the electro-optical device drive control unit that drives and controls the electro-optical device, A temperature detection unit that is disposed in the vicinity of the light source device and detects the temperature of the light source device, wherein the electro-optical device drive control unit performs predetermined processing on the image information, and the gradation level of the image information, and The electro-optical device includes a characteristic changing unit that changes a gradation-light transmittance characteristic or a gradation-light reflectance characteristic in light transmittance or light reflectance of the electro-optical device. The The lowest limit value of the light transmittance or light reflectance of the electro-optical device is set based on the detected temperature, the lowest limit value set, and the highest light transmittance or light reflectance of the electro-optical device The gradation-light transmittance characteristic or the gradation-light reflectance characteristic is changed based on the value.

Here, as described above, the electro-optical device is a type that performs light modulation by transmitting the light beam emitted from the light source device, or performs light modulation by reflecting the light beam emitted from the light source device. Any of the types to be used may be adopted.
In addition, the lower limit value of the light transmittance or light reflectance of the electro-optical device is set, and the gradation-light transmission is based on the set lower limit value and the highest value of the light transmittance or light reflectance of the electro-optical device. To change the rate characteristic or the gradation-light reflectance characteristic, as described above, for example, gradation conversion processing is performed on the image information, and the light transmittance or light of the electro-optical device in the low gradation region of the image information is obtained. A process for changing the reflectance can be employed. In addition to this process, a predetermined offset voltage is added to the driving voltage for driving the electro-optical device, and the driving voltage applied to the electro-optical device is shifted to the high voltage side, thereby reducing the lower order of the image information. You may employ | adopt the process which changes the light transmittance or light reflectivity of the electro-optical apparatus in an adjustment | control area | region.
In the present invention, the electro-optical device drive control unit constituting the projector includes a characteristic changing unit. The characteristic changing unit sets the lower limit value of the light transmittance or light reflectance of the electro-optical device based on the detected temperature detected by the temperature detecting unit, and sets the lower limit value and the electro-optical device. The gradation-light transmittance characteristic or the gradation-light reflectance characteristic is changed based on the maximum value of the light transmittance or the light reflectance. Accordingly, based on the detected temperature detected by the temperature detection unit, for example, gradation conversion processing is performed on the image information, and the light transmittance or light reflection of the electro-optical device in the low gradation region of the image information is performed. By changing the gradation-light transmittance characteristic or gradation-light reflectance characteristic in the electro-optical device by improving the rate, the luminous flux absorbed by the electro-optical device is reduced, and the heat generation amount of the electro-optical device is reduced. Can be made. Accordingly, the temperature of the electro-optical device can be reduced, and the temperature rise inside the projector can be suppressed. In addition, this makes it possible to avoid an abnormal state due to an increase in the temperature inside the projector, and there is no need to carry out a control to turn off the power when the internal temperature becomes an abnormal state. Since it does not disappear suddenly, the convenience of the projector can be improved.
Further, even when a light emitting diode element is employed as the light source device, for example, according to the temperature rise of the light source device with the lapse of the driving time of the light source device, that is, according to the decrease in luminance of the light source device. If the gradation-light transmittance characteristic or the gradation-light reflectance characteristic is controlled to be changed by the above-described characteristic changing unit, the light transmittance or light reflection of the electro-optical device according to the decrease in the luminance of the light source device. By improving the rate, it is possible to suppress a decrease in luminance of the optical image.

In the projector according to the aspect of the invention, the light source device includes a plurality of light sources that can emit a plurality of color lights, the temperature detection unit includes a plurality of light sources corresponding to the plurality of light source devices, and the electro-optical device includes: A plurality of light source devices corresponding to the plurality of light source devices, and a color combining optical device that combines and emits optical images for each of the color lights formed by the plurality of electro-optical devices, and the characteristic changing unit includes: A predetermined process is performed on the image information corresponding to the plurality of color lights based on a plurality of detected temperatures detected by a plurality of temperature detection units, and each gradation-light transmittance characteristic or It is preferable to change so that each gradation-light reflectance characteristic becomes substantially equal.
Here, each gradation-light transmittance characteristic or each gradation-light reflectance characteristic is substantially equal means that each gradation-light transmittance characteristic curve or each gradation-light reflectance characteristic curve has the same shape or a similar shape. It means having.
In the present invention, the light source device includes a plurality of light sources capable of emitting a plurality of color lights. Moreover, the temperature detection part is comprised by two or more corresponding to several light source devices. Furthermore, a plurality of electro-optical devices are configured corresponding to a plurality of light source devices. The characteristic changing unit performs predetermined processing on the image information corresponding to the plurality of color lights based on the detected temperatures detected by the plurality of temperature detection units, and each gradation-light transmittance between the plurality of electro-optical devices. The characteristic or each gradation-light reflectance characteristic is changed to be substantially equal. Thus, even if each gradation-light transmittance characteristic or each gradation-light reflectance characteristic is changed by the characteristic changing unit, according to each gradation-light transmittance characteristic or each gradation-light reflectance characteristic. It is possible to improve the color tone of each optical image formed by each electro-optical device, and the optical image synthesized by the color synthesizing optical device is enlarged and projected by the projection optical device, so that there is no color unevenness. It is possible to project an optical image.

In the projector according to the aspect of the invention, the light source device includes a plurality of light sources that can emit a plurality of color lights, the temperature detection unit includes a plurality of light sources corresponding to the plurality of light source devices, and the electro-optical device includes: A plurality of light source devices corresponding to the plurality of light source devices, and a color combining optical device that combines and emits optical images for each of the color lights formed by the plurality of electro-optical devices, and the characteristic changing unit includes: A predetermined process is performed on the image information corresponding to the plurality of color lights based on a plurality of detected temperatures detected by a plurality of temperature detection units, and each gradation-light transmittance characteristic or It is preferable to change so that each gradation-light reflectance characteristic is substantially different.
Here, each gradation-light transmittance characteristic or each gradation-light reflectance characteristic is substantially different from each other. Each gradation-light transmittance characteristic curve or each gradation-light reflectance characteristic curve has the same shape or a similar shape. Does not have.
In the present invention, the light source device includes a plurality of light sources capable of emitting a plurality of color lights. Moreover, the temperature detection part is comprised by two or more corresponding to several light source devices. Furthermore, a plurality of electro-optical devices are configured corresponding to a plurality of light source devices. The characteristic changing unit performs predetermined processing on the image information corresponding to the plurality of color lights based on the detected temperatures detected by the plurality of temperature detection units, and each gradation-light transmittance between the plurality of electro-optical devices. The characteristic or each gradation-light reflectance characteristic is changed so as to be substantially different. Thus, for example, when a plurality of light emitting diode elements are employed as a plurality of light source devices, the amount of heat generated when each light source device is driven is different, and the temperature of each light source device is different, that is, the brightness of each light source device is different. Even so, each light source device can be obtained by changing each gradation-light transmittance characteristic or each gradation-light reflectance characteristic to be substantially different between a plurality of electric light source devices according to the temperature of each light source device. Therefore, it is possible to form an optical image on each electro-optical device corresponding to the different luminances, and to improve the color balance of the optical image synthesized by the color synthesizing optical device. Therefore, it is possible to project a good optical image without color unevenness by enlarging and projecting the optical image synthesized by the color synthesizing optical device by the projection optical device.

In the projector according to the aspect of the invention, it is preferable that the light source device includes a solid light emitting element.
Here, examples of the solid state light emitting device include a light emitting diode device and a semiconductor laser.
According to the present invention, since the light source device is configured to include a solid light emitting element, the amount of heat generated during driving can be reduced compared to a light source device such as a high-pressure mercury lamp or a metal halide lamp, and the temperature of the light source device can be reduced. The rise can be further suppressed, and the temperature rise inside the projector can be further suppressed. In addition, power consumption during driving can be reduced. Furthermore, it becomes a structure which can implement intermittent lighting control of a light source device easily. Furthermore, the light source device can be reduced in size and weight.

According to the projector control method of the present invention, the light source device and the optical modulation are performed by changing the light transmittance or light reflectance of the light beam emitted from the light source device according to the gradation level of the image information. An electro-optical device that forms an image, a projection optical device that magnifies and projects an optical image formed by the electro-optical device, a light source drive control unit that controls intermittent lighting of the light source device, and a light source device in the vicinity A projector control method including a temperature detection unit that detects a temperature of the light source device, wherein the temperature detection unit detects a temperature of the light source device, and the light source drive control unit includes the temperature detection unit. A temperature determination step of comparing the detected temperature detected in the temperature detection step with a predetermined first temperature threshold value to determine whether or not the detected temperature exceeds the first temperature threshold value; and the light source drive control unit When the temperature determination step determines that the detected temperature has exceeded the first temperature threshold, the light source device is intermittently lit so as to shorten the lighting time per unit time when the light source device is intermittently lit. And a duty ratio suppression control step for controlling.
According to the present invention, since the projector control method includes the temperature detection step, the temperature determination step, and the duty ratio suppression control step, it is possible to enjoy the same operations and effects as those of the projector described above.

According to the projector control method of the present invention, the light source device and the optical modulation are performed by changing the light transmittance or light reflectance of the light beam emitted from the light source device according to the gradation level of the image information. An electro-optical device that forms an image, a projection optical device that magnifies and projects an optical image formed by the electro-optical device, an electro-optical device drive control unit that drives and controls the electro-optical device, and a light source device near the light source device A projector control method comprising: a temperature detection unit that is arranged and detects a temperature of the light source device, wherein the temperature detection unit detects a temperature of the light source device; and the electro-optical device drive control A predetermined processing is performed on the image information based on the detected temperature detected in the temperature detecting step, and the gradation level of the image information and the light transmittance or light of the electro-optical device And a characteristic changing step of changing a gradation-light transmittance characteristic or a gradation-light reflectance characteristic in the emissivity, wherein the characteristic changing step is based on the detection temperature and the light transmittance or light of the electro-optical device. A minimum limit value of reflectance is set, and the gradation-light transmittance characteristic or the gradation-light is based on the set minimum limit value and the maximum value of the light transmittance or light reflectance of the electro-optical device. The reflectance characteristic is changed.
According to the aspect of the invention, the projector control method includes a temperature detection step and a characteristic change step. In the characteristic change step, the light transmittance of the electro-optical device or the light transmission rate based on the detected temperature detected in the temperature detection step. Sets the minimum lower limit value of the light reflectance, and the gradation-light transmittance characteristic or the gradation-light reflectance based on the set lower limit value and the maximum value of the light transmittance or the light reflectance of the electro-optical device Since the characteristics are changed, the same operation and effect as the projector described above can be enjoyed.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[Configuration of projector]
FIG. 1 is a diagram schematically showing a schematic configuration of a projector 1 according to the present embodiment.
The projector 1 modulates a light beam emitted from a light source according to image information to form an optical image, and enlarges and projects the formed optical image on a screen. The projector 1 includes a light source device 2, three polarization conversion devices 3, three electro-optical devices 4, a cross dichroic prism 5 as a color synthesis optical device, a projection lens 6 as a projection optical device, And a control device (not shown).

The light source device 2 performs intermittent lighting that is repeatedly turned on and off under the control of a control device described later, and emits a light beam toward the polarization conversion device 3. As shown in FIG. 1, the light source device 2 includes an R color light LED (Light Emitting Diode) module 2R that emits R color light, a G color light LED module 2G that emits G color light, and a G color light that emits B color light. It is comprised with LED module 2B for colored lights.
These LED modules 2R, 2G, and 2B have substantially the same configuration, and although not specifically illustrated, a plurality of LED elements that are solid light emitting elements are arrayed on a Si substrate. The LED elements constituting the LED modules 2R, 2G, and 2B are formed so that the types of crystals, additives, and the like are different, and emit R light, G light, and B light, respectively. Each of the LED modules 2R, 2G, and 2B is formed with a light source driving circuit that applies a driving voltage to each LED element in accordance with a control command from a control device described later.

In addition, these LED modules 2R, 2G, and 2B are provided with a temperature detection sensor 20 as a temperature detection unit including a thermistor or the like in order to detect an overheating state of each LED element. Specifically, the temperature detection sensor 20 corresponds to each of the LED modules 2R, 2G, and 2B, and is in contact with the LED modules 2R, 2G, and 2B. The sensor 20G and the temperature detection sensor 20B for B color light are comprised.
In the present embodiment, the temperature detection sensor 20 is provided so as to be in contact with the LED modules 2R, 2G, and 2B. However, the position where the temperature detection sensor 20 is provided is not limited to this, and the LED modules 2R, 2G are provided. , 2B may be provided at any position.

The polarization conversion device 3 includes three polarization conversion devices 3R, 3G, and 3B corresponding to each color light emitted from the light source device 2, and the polarization direction of each color light emitted from the light source device 2 is a straight line that is substantially in one direction. Align with polarized light.
Although not shown, these polarization conversion devices 3R, 3G, and 3B have a configuration in which polarization separation films and reflection mirrors that are inclined with respect to the illumination optical axis are alternately arranged. The polarization separation film transmits one polarized light beam among the P-polarized light beam and S-polarized light beam included in each color light, and reflects the other polarized light beam. The reflected other polarized light beam is bent by the reflecting mirror and emitted in the emission direction of the one polarized light beam, that is, the direction along the illumination optical axis. Any of the emitted polarized light beams is polarized and converted by the phase difference plate provided on the light beam exit surface of the polarization conversion devices 3R, 3G, and 3B, and the polarization directions of almost all the polarized light beams are aligned. By using such polarization conversion devices 3R, 3G, and 3B, the light beam emitted from the light source device 2 can be aligned with the polarized light beam in substantially one direction, so that the light source light used in the electro-optical device 4 is used. The rate can be improved.
In this embodiment, the polarization conversion devices 3R and 3B emit R and B color light emitted from the R color light LED module 2R and the B color light LED module 2B in a P-polarized light beam, and the polarization conversion device 3G emits G color light. The colored light emitted from the LED module 2G is emitted in alignment with the S-polarized light beam.

The electro-optical device 4 includes three electro-optical devices 4R, 4G, and 4B corresponding to the respective color lights emitted from the polarization conversion devices 3R, 3G, and 3B, and an image to be input under the control of the control device 7 described later. The incident color light is modulated by changing the light transmittance of the light beams emitted from the polarization conversion devices 3R, 3G, and 3B according to the gradation level of the signal to form an optical image. These electro-optical devices 4 include three incident-side polarizing plates 41R, 41G, and 41B, three liquid crystal panel modules 42R, 42G, and 42B, and three emission-side polarizing plates 43R, 43G, and 43B.
The incident-side polarizing plates 41R, 41G, and 41B receive the respective color lights whose polarization directions are aligned in approximately one direction by the polarization conversion device 3, and of the incident light beams, polarization of the light beams aligned by the polarization conversion device 3 Only polarized light in substantially the same direction as the axis is transmitted and other light beams are absorbed. That is, the incident-side polarizing plates 41R and 41B transmit the P-polarized light beam emitted from the polarization conversion devices 3R and 3B, and the incident-side polarizing plate 41G transmits the S-polarized light beam emitted from the polarization conversion device 3G. These incident-side polarizing plates 41R, 41G, and 41B have a configuration in which a polarizing film is attached to a substrate such as sapphire glass or crystal.

The exit-side polarizing plates 43R, 43G, and 43B have substantially the same configuration as the incident-side polarizing plates 41R, 41G, and 41B. Of the light beams emitted from the liquid crystal panel modules 42R, 42G, and 42B, the incident-side polarizing plates 41R, Only light beams having a polarization axis orthogonal to the light beam transmission axis in 41G and 41B are transmitted, and other light beams are absorbed. That is, the exit-side polarizing plates 43R and 43B transmit the S-polarized light beam, and the exit-side polarizing plate 43G transmits the P-polarized light beam.
Although not specifically shown, the liquid crystal panel modules 42R, 42G, and 42B include a liquid crystal panel in which a liquid crystal that is an electro-optical material is hermetically sealed on a pair of transparent glass substrates, and an image signal that is output from a control device described later. And a liquid crystal panel driving IC (Integrated Circuit) for applying a predetermined driving voltage corresponding to an image to the liquid crystal panel. The liquid crystal panel modules 42R, 42G, and 42B control the liquid crystal alignment state of the liquid crystal panel according to, for example, the driving voltage supplied from the liquid crystal panel driving IC, and the incident side polarizing plates 41R, 41G, and 41B. The polarization direction of the polarized light beam emitted from is modulated.
The light transmittance is defined by the ratio of the light amount of the light beam transmitted through the electro-optical device 4 to the light amount of the light beam emitted from the light source device 2.

The cross dichroic prism 5 is an optical element that synthesizes an optical image modulated for each color light emitted from each electro-optical device 4R, 4G, 4B to form a color image. The cross dichroic prism 5 has a substantially square shape in plan view in which four right-angle prisms 51 are bonded together, and dielectric multilayer films 52A and 52B are formed on the interface where the right-angle prisms 51 are bonded together. The dielectric multilayer film 52A reflects the S-polarized light beam emitted from the electro-optical device 4R and transmits the P-polarized light beam emitted from the electro-optical device 4G. The dielectric multilayer film 52B reflects the S-polarized light beam emitted from the electro-optical device 4B and transmits the P-polarized light beam emitted from the electro-optical device 4G. In this way, the three color lights emitted from the electro-optical devices 4R, 4G, and 4B are combined.
The projection lens 6 enlarges and projects the color image formed by the cross dichroic prism 5 on the screen 100, is configured as a combined lens in which a plurality of lenses are combined, and is housed in a lens barrel.

[Control device structure]
FIG. 2 is a block diagram showing a control structure of the light source device 2 and the electro-optical device 4 by the control device 7.
The control device 7 performs intermittent lighting control of the LED modules 2R, 2G, and 2B, performs predetermined processing on an image signal input from an external device, and a liquid crystal panel module according to the image signal subjected to this processing 42R, 42G, and 42B are driven and controlled. As shown in FIG. 2, the control device 7 includes a video signal input unit 71, a control unit 72, and a storage unit 73.

The video signal input unit 71 is a part for inputting video signals output from various external devices. As illustrated in FIG. 2, the video signal input unit 71 includes a first input unit 711, a second input unit 712, and a third input unit 713.
The first input unit 711 is a part to which a plurality of image signals output from a personal computer are provided, and includes a first video selector 711A and an ADC (Analog to Digital Converter) 711B as shown in FIG.
The first video selector 711A selects and outputs one of the input image signals in accordance with the selection signal given from the control unit 72. The image signal output from the first video selector 711A includes three color analog image signals of red (R), green (G), and blue (B), and a horizontal synchronizing signal and a vertical synchronizing signal. Yes. Such an image signal is called a component signal.
The ADC 711B converts the three analog image signals output from the first video selector 711A into digital image signals by the AD conversion circuit in the ADC 711B. The digital image signal is temporarily recorded in the storage unit 73 via the control unit 72. The recorded digital image signal is sequentially rewritten according to the digital image signal output from the ADC 711B.

The second input unit 712 is a part to which a plurality of video signals output from a video recorder, a television, or the like is given, and includes a second video selector 712A and a video decoder 712B as shown in FIG.
The second video selector 712A selects and outputs one of the input video signals according to the selection signal given from the control unit 72. These video signals are image signals in which a luminance signal, a color signal, and a synchronization signal are superimposed, and are called composite signals.
The video decoder 712B separates the horizontal synchronization signal and the vertical synchronization signal from the composite signal output from the second video selector 712A and converts them into three digital image signals of R, G, and B. The digital image signal is temporarily recorded in the storage unit 73 via the control unit 72. The recorded digital image signal is sequentially rewritten according to the digital image signal output from the video decoder 712B.

  The third input unit 713 is a dedicated receiver for inputting a digital image signal and a clock signal by a transmission method such as a TMDS (Transition Minimized Differential Signaling) method. In other words, the third input unit 713 can directly input a digital image signal from an external device.

The control unit 72 includes an arithmetic processing unit such as a CPU (Central Processing Unit), and reads and executes a control program stored in a ROM (Read Only Memory) or the like (not shown). The LED modules 2R, 2G, 2B intermittent lighting control and drive control of the liquid crystal panel modules 42R, 42G, 42B. As illustrated in FIG. 2, the control unit 72 includes a sensor signal receiving unit 721, a light source drive control unit 722, and an electro-optical device drive control unit 723.
The sensor signal receiving unit 721 is a part that receives the temperature sensor signals detected by the temperature detection sensors 20R, 20G, and 20B for the R, G, and B color lights, and is detected by the temperature detection sensors 20R, 20G, and 20B. Each of the temperature sensor signals thus converted is converted into a digital signal and received by the sensor signal receiving unit 721. Then, the sensor signal receiving unit 721 outputs a digital signal corresponding to each temperature detected by each temperature detection sensor 20R, 20G, 20B to the light source drive control unit 722 and the electro-optical device drive control unit 723.

The light source drive control unit 722 drives and controls the LED modules 2R, 2G, and 2B based on the temperatures of the LED modules 2R, 2G, and 2B corresponding to the temperature sensor signals received by the sensor signal reception unit 721. As shown in FIG. 2, the light source drive control unit 722 includes a duty ratio control unit 722A and a control state switching unit 722B.
The duty ratio control unit 722A outputs a predetermined control command to each light source drive circuit that constitutes each LED module 2R, 2G, 2B, and sends a drive signal having a predetermined duty ratio to each LED module 2R, Each LED element constituting 2G and 2B is output, and each LED element is intermittently lit at a predetermined duty ratio (ratio of turn-on time per unit time to turn-off time per unit time). Further, the duty ratio control unit 722A is based on the temperature of each LED module 2R, 2G, 2B corresponding to each temperature sensor signal received by the sensor signal receiving unit 721 and the information stored in the storage unit 73. Duty ratio control is performed to similarly change the duty ratio of each drive signal output from each light source drive circuit. Although specifically described later, the duty ratio control unit 722A increases the duty ratio of the drive signal according to the temperature rise of the LED modules 2R, 2G, and 2B in accordance with a control command from the control state switching unit 722B. The duty ratio of the drive signal is changed to a low value according to the duty ratio increase control to be performed and the temperatures of the LED modules 2R, 2G, and 2B, and the duty ratio is changed according to the decrease in the temperature of the LED modules 2R, 2G, and 2B. Duty ratio suppression control for gradually increasing the ratio is performed.
The control state switching unit 722B is the highest temperature among the temperatures of the LED modules 2R, 2G, and 2B corresponding to the temperature sensor signal received by the sensor signal receiving unit 721 according to the information stored in the storage unit 73. Is within the predetermined temperature range, the control state by the duty ratio control unit 722A is switched from duty ratio increase control to duty ratio suppression control.

The electro-optical device drive control unit 723 appropriately reads the digital image signal output from the video signal input unit 71 and stored in the storage unit 73, performs predetermined processing on the read digital image signal, and performs the processing. An image signal corresponding to the image is output to each of the liquid crystal panel modules 42R, 42G and 42B of the electro-optical device 4 to form a predetermined optical image. The optical image corresponding to the image signal input from the external device via the video signal input unit 71 is not limited to the configuration in which the liquid crystal panel modules 42R, 42G, and 42B are formed. The image data stored in the image data may be read out, predetermined processing is performed on the image data, and optical images corresponding to the processed image data may be formed in the liquid crystal panel modules 42R, 42G, and 42B. As shown in FIG. 2, the electro-optical device drive control unit 723 includes an image processing unit 723A and a characteristic changing unit 723B.
The image processing unit 723A performs image size adjustment processing such as enlargement / reduction, trapezoidal distortion correction processing, image quality adjustment processing, gamma correction processing, and the like on the digital image signal output from the video signal input unit 71. Then, the image processing unit 723A outputs an image signal corresponding to the processed image to the characteristic changing unit 723B.

  The characteristic changing unit 723B performs predetermined processing on the image signal output from the image processing unit 723A, and changes the gradation level of the image signal and the gradation-light transmittance characteristic in the light transmittance of the electro-optical device 4. change. In the present embodiment, the gradation-light transmittance characteristic changing process by the characteristic changing unit 723B is performed using the temperature of each LED module 2R, 2G, 2B corresponding to the temperature sensor signal received by the sensor signal receiving unit 721. This is performed when the highest temperature is within a predetermined temperature range (when the duty ratio suppression control of the light source device 2 is performed by the light source drive control unit 722). For this reason, the characteristic changing unit 723B determines whether the highest temperature among the temperatures of the LED modules 2R, 2G, and 2B is within a predetermined temperature range according to the information stored in the storage unit 73. Then, the gradation-light transmittance characteristic changing process is performed. Note that the gradation-light transmittance characteristic changing process by the characteristic changing unit 723B is not limited to the processing method described above, and for example, may be configured to always be performed when the projector 1 is driven.

FIG. 3 is a diagram schematically illustrating the gradation-light transmittance characteristic changing process by the characteristic changing unit 723B. In FIG. 3, in order to simplify and explain the gradation-light transmittance characteristic changing process by the characteristic changing unit 723 </ b> B, the gradation-light transmittance characteristic before the change process is performed is represented by an electro-optical device. 4 characteristic gradation-light transmittance characteristics. In practice, the characteristic changing unit 723B performs the changing process on the gradation-light transmittance characteristic on which the gamma correction process is performed by the image processing unit 723A, although illustration is omitted.
In FIG. 3, the horizontal axis represents the gradation value of the image signal input to the characteristic changing unit 723 </ b> B, and the vertical axis represents the light transmittance of the electro-optical device 4. The gradation-light transmittance characteristic curve CS is a gradation-light transmittance characteristic curve unique to the electro-optical device 4.
As shown in FIG. 3, the characteristic changing unit 723 </ b> B is based on the temperature of each LED module 2 </ b> R, 2 </ b> G, 2 </ b> B corresponding to each temperature sensor signal received by the sensor signal receiving unit 721. Is set to L1 or L2. Then, the gradation-light transmittance characteristic curve CS is changed to the gradation-light transmittance characteristic curve C1 or C2 based on the set lower limit L1 or L2 and the maximum value H of the light transmittance of the electro-optical device 4. To do.
That is, as shown in FIG. 3, the characteristic changing unit 723B performs gradation conversion processing on the image signal output from the image processing unit 723A, and the light transmission of the electro-optical device 4 in the low gradation region A, for example. Improve the rate.

Here, the setting of the lower limit L1 or L2 of the characteristic changing unit 723B is set in the storage unit 73 and the temperature of each LED module 2R, 2G, 2B corresponding to each temperature sensor signal received by the sensor signal receiving unit 721. Based on the stored information.
In FIG. 3, the characteristic changing unit 723B sets two minimum lower limit values L1 and L2, respectively, and changes them to two gradation-light transmittance characteristic curves C1 and C2 corresponding to the lowest limit values L1 and L2, respectively. In this embodiment, the characteristic changing unit 723B sets three or more minimum lower limit values, and sets three or more gradation-light transmittance characteristic curves corresponding to these minimum lower limit values. Shall be changed. Not limited to this, the characteristic changing unit 723B sets one or two minimum lower limit values, and changes to one or two gradation-light transmittance characteristic curves corresponding to the set minimum lower limit values. Also good.

The storage unit 73 stores data output from the control unit 72 and stores data set in advance by a user or the like. The storage unit 73 includes a frame memory 731, a duty ratio control data storage unit 732, and a gradation-light transmittance characteristic data storage unit 733.
The frame memory 731 is composed of a rewritable SRAM (Static Random Access Memory) or the like, and is output from an external device as described above and records a digital image signal via the video signal input unit 71. As described above, the image signal output from the external device is temporarily recorded in the frame memory 731, and the electro-optical device drive control unit 723 of the control unit 72 performs a predetermined process based on the recorded image signal. The liquid crystal panel modules 42R, 42G, and 42B are driven and controlled based on the applied image signals.

FIG. 4 is a diagram schematically showing a table structure stored in the duty ratio control data storage unit 732.
The duty ratio control data storage unit 732 is configured by a rewritable SRAM or the like, and information related to duty ratio control by the light source drive control unit 722 is stored on the tables T1, T2, and T3.
Here, as shown in FIG. 4A, the table T1 is configured as a table in which the duty ratios with respect to the temperatures of the LED modules 2R, 2G, and 2B are set. This table T1 is used when the duty ratio control unit 722A performs duty ratio increase control, and is not represented by specific numerical values in FIG. The duty ratio is set to increase as the temperature of the LED modules 2R, 2G, and 2B increases.

  Similarly, the table T2 is configured as a table in which duty ratios with respect to the temperatures of the LED modules 2R, 2G, and 2B are set as shown in FIG. 4B. This table T2 is used when the duty ratio control unit 722A performs the duty ratio suppression control, and is not represented by specific numerical values in FIG. The duty ratio is set to decrease as the temperature rises in the LED modules 2R, 2G, and 2B.

On the other hand, as shown in FIG. 4C, the table T3 is configured as a table in which the timing for switching the duty ratio control by the duty ratio control unit 722A by the control state switching unit 722B is set. Although not represented by specific numerical values in FIG. 4C, the temperature threshold 1 is set to a temperature higher than the temperature threshold 2.
Here, when the highest temperature among the temperatures of the LED modules 2R, 2G, and 2B exceeds the temperature threshold 1 as the first temperature threshold, the duty ratio increase control by the duty ratio control unit 722A is controlled by the duty ratio suppression control. It is time to switch to. Further, when the highest temperature among the temperatures of the LED modules 2R, 2G, and 2B becomes equal to or lower than the temperature threshold 2 as the second temperature threshold, the duty ratio suppression control by the duty ratio controller 722A is controlled to increase the duty ratio. It is time to switch to.

Specifically, FIG. 5 is a graph of information stored in the duty ratio control data storage unit 732.
As shown in FIG. 5, the table T1 used when the duty ratio increase control is performed is set so that the duty ratio increases (the lighting time per unit time becomes longer) as the temperature rises. Information is stored.
On the other hand, in the table T2 used when the duty ratio suppression control is performed, the duty ratio corresponding to the temperature threshold 1 is set lower than the duty ratio corresponding to the temperature threshold 1 in the table T1, and the temperature In accordance with the decrease, information is stored that is set so that the duty ratio gradually increases from the low duty ratio (the lighting time per unit time is lengthened).
That is, in the tables T1 and T2, the correlation of the duty ratio with respect to the temperature of the LED modules 2R, 2G, and 2B is set in reverse, and the temperature of the temperature threshold 2 set in the table T3 as shown in FIG. The duty ratios in the tables T1 and T2 are set to be close values, and the duty ratios in the tables T1 and T2 are set to be separated from each other at the temperature of the temperature threshold 1 set in the table T3. Yes.

  In FIGS. 4 and 5, one table T1 and one T2 are shown, but actually, each table is composed of three corresponding to each LED module 2R, 2G, and 2B. In the tables T1 and T2 corresponding to the LED modules 2R, 2G, and 2B, the duty ratios corresponding to the predetermined temperatures are set so that each color light emitted from the LED modules 2R, 2G, and 2B has a predetermined hue. Is set at a predetermined ratio. That is, when the duty ratio control unit 722A of the light source drive control unit 722 performs the duty ratio increase control and duty ratio suppression control of the LED modules 2R, 2G, and 2B based on the tables T1 and T2, the LED module 2R, Each color light emitted from 2G and 2B has a predetermined hue, and the hue duty ratio control according to the present invention is performed.

The gradation-light transmittance characteristic data storage unit 733 includes a rewritable SRAM or the like, and changes the gradation-light transmittance characteristic curve in the characteristic change unit 723B of the electro-optical device drive control unit 723. Information used is stored.
Although not shown in the gradation-light transmittance characteristic data storage unit 733, the gradation of the image signal output from the image processing unit 723A corresponding to each temperature of the LED modules 2R, 2G, and 2B is converted. The conversion table to be stored is stored.
The conversion table includes three conversion tables corresponding to the three electro-optical devices 4R, 4G, and 4B. These conversion tables change, for example, the gradation-light transmittance characteristic curve CS (FIG. 3) to each gradation-light transmittance characteristic curve C1 or C2 (FIG. 3) in correspondence with a predetermined temperature, and change the gradation-light transmittance characteristic curve CS (FIG. 3). -When an optical image is formed by each electro-optical device 4R, 4G, 4B according to the light transmittance characteristic curve C1 or C2, each optical image is set to have a predetermined hue. That is, each gradation-light transmittance characteristic curve corresponding to a predetermined temperature is changed so as to have the same shape or a similar shape.
The gradation-light transmittance characteristic data storage unit 733 stores a change processing table that is substantially the same as the duty ratio control switching table T3 in the duty ratio control data storage unit 732, although not shown. In the change processing table, when the highest temperature among the temperatures of the LED modules 2R, 2G, and 2B exceeds the temperature threshold 1, the change processing of the gradation-light transmittance characteristic is performed by the characteristic changing unit 723B. The timing at which the highest temperature among the temperatures of the LED modules 2R, 2G, and 2B becomes equal to or lower than the temperature threshold 2 is the timing to end the change process.

Next, control operations of the light source device 2 and the electro-optical device 4 by the control device 7 will be described.
FIG. 6 is a flowchart for explaining a control operation by the control device 7.
FIG. 7 is a diagram showing the transition of the temperatures of the LED modules 2R, 2G, 2B under the control of the control device 7.
FIG. 8 is a diagram illustrating a change in the duty ratio when the LED modules 2R, 2G, and 2B are intermittently turned on under the control of the control device 7.
6 shows the transition of the temperature of the LED module, which is the highest temperature among the LED modules 2R, 2G, and 2B. Similarly, in FIG. 7, the LED module 2R, 2G, and 2B has the highest temperature. It shows the transition of the duty ratio when intermittently lighting the LED module at a high temperature.
When the control device 7 inputs a signal indicating that the projector 1 is activated by an input operation of the remote controller or the like by the user, the light source drive control unit 722 of the control unit 72 in the control device 7 switches each LED module 2R, 2G, 2B. A predetermined control command is output to each light source driving circuit to be configured, and a driving signal having a predetermined duty ratio is output from each light source driving circuit to each LED element. And each LED element implements intermittent lighting of ON and OFF according to a drive signal.
In addition, the electro-optical device drive control unit 723 of the control unit 72 appropriately reads an image signal input from an external device via the video signal input unit 71 and stored in the frame memory 731 of the storage unit 73, and converts the image signal into the read image signal. A predetermined process is performed on the image signal, and the processed image signal is output to each of the liquid crystal panel modules 42R, 42G, and 42B. And each liquid crystal panel drive IC which comprises each liquid crystal panel module 42R, 42G, 42B outputs the drive signal corresponding to the input image signal to each liquid crystal panel, and modulates the light beam inject | emitted from each LED element. In this state, the gradation-light transmittance characteristic changing process is not performed by the characteristic changing unit 723B of the electro-optical device drive control unit 723, and the gradation subjected to the gamma correction process by the image processing unit 723A. Each optical image is formed in each electro-optical device 4R, 4G, 4B according to the light transmittance characteristics.

After the projector 1 is started, as shown in FIG. 7, as the driving time of the projector 1 elapses, the temperatures of the LED modules 2R, 2G, and 2B gradually increase due to the lighting of the LED elements.
In such a state, each temperature detection sensor 20R, 20G, 20B detects the temperature of each LED module 2R, 2G, 2B (processing S1: temperature detection step). Then, each temperature detection sensor 20R, 20G, 20B outputs each temperature sensor signal corresponding to each detected temperature to the control device 7. In addition, each temperature detection sensor 20R, 20G, 20B detects the temperature of each LED module 2R, 2G, 2B for every predetermined time, for example, and each temperature sensor signal corresponding to the detected temperature is sequentially sent to the control apparatus 7. Shall be output.

Thereafter, the control device 7 performs duty ratio increase control of the LED modules 2R, 2G, and 2B based on the input temperature sensor signals as described below (processing S2).
The control unit 72 of the control device 7 sequentially inputs each temperature sensor signal via the sensor signal receiving unit 721 and recognizes the temperature of each LED module 2R, 2G, 2B. The duty ratio control unit 722A of the light source drive control unit 722 corresponds to the highest temperature among the recognized temperatures with reference to the duty ratio increase control table T1 stored in the duty ratio control data storage unit 732 of the storage unit 73. Each duty ratio to be calculated is calculated. Then, the duty ratio control unit 722A performs intermittent lighting control of the LED modules 2R, 2G, and 2B at the calculated duty ratios.

When the duty ratio increase control (process S2) is performed by the light source drive control unit 722, the control unit 72 sequentially inputs each temperature sensor signal via the sensor signal receiving unit 721, and each LED module 2R, 2G. , 2B temperature is recognized. Here, the control unit 72 compares the highest temperature among the recognized temperatures with the temperature threshold value 1 stored in the duty ratio control data storage unit 732 of the storage unit 73, and among the recognized temperatures. It is determined whether or not the highest temperature exceeds the temperature threshold value 1 (process S3: temperature determination step).
Here, when it is determined as “N” in the process S3, that is, when it is determined that none of the recognized temperatures exceeds the temperature threshold 1, the above-described duty ratio increase control (process) Continue S2). The duty ratio control unit 722A repeatedly performs the duty ratio increase control (process S2), and as shown in FIG. 8, according to the duty ratio increase control table T1, the temperatures of the recognized LED modules 2R, 2G, and 2B are detected. In response to the increase of the LED module, the duty ratios when the LED modules 2R, 2G, and 2B are intermittently lit are gradually increased, that is, the lighting time per unit time is gradually increased. Then, by gradually increasing the lighting time per unit time when intermittently lighting each LED module 2R, 2G, 2B, the temperature of each LED module 2R, 2G, 2B further increases as shown in FIG. To do.

Then, the duty ratio increase control (process S2) is repeatedly performed, and when it is determined as “Y” in process S3, that is, it is determined that the highest temperature among the recognized temperatures exceeds the temperature threshold value 1. In this case, the control state switching unit 722B outputs a predetermined control command to the duty ratio control unit 722A, and switches the control state of the duty ratio control unit 722A from duty ratio increase control to duty ratio suppression control (Process S4). .
After the process S4, the duty ratio control unit 722A performs the duty ratio suppression control of each LED module 2R, 2G, 2B as shown below according to the control command from the control state switching unit 722B (process S5: Duty ratio suppression control step).
The duty ratio control unit 722A refers to the duty ratio suppression control table T2 stored in the duty ratio control data storage unit 732 of the storage unit 73 and is higher than the temperature threshold 1 of the LED modules 2R, 2G, 2B. Calculate the duty ratio corresponding to the temperature. Then, the duty ratio control unit 722A performs intermittent lighting control of the LED modules 2R, 2G, and 2B at the calculated duty ratios.
As described above, when the duty ratio increase control (process S2) is switched to the duty ratio suppression control (process S5), as shown in FIG. 8, the duty ratio when the LED modules 2R, 2G, and 2B are intermittently controlled is changed. It is changed to a lower value, that is, the lighting time per unit time is shortened. For this reason, as shown in FIG. 7, the temperature of each LED module 2R, 2G, 2B decreases.

Further, when it is determined as “Y” in the process S3, that is, when it is determined that the highest temperature among the recognized temperatures exceeds the temperature threshold 1, the electro-optical device drive control unit 723 The characteristic changing unit 723B performs the gradation-light transmittance characteristic changing process as described below (process S6: characteristic changing step).
The characteristic changing unit 723B refers to the conversion table stored in the gradation-light transmittance characteristic data storage unit 733 of the storage unit 73, and increases the temperature exceeding the temperature threshold 1 of each of the LED modules 2R, 2G, 2B. Based on this, gradation conversion processing is performed on the image signal output from the image processing unit 723A so that the lower limit value of the light transmittance in the electro-optical devices 4R, 4G, and 4B is increased, and gradation-light transmission is performed. Change each rate characteristic curve. For example, with reference to FIG. 3, the characteristic changing unit 723B outputs from the image processing unit 723A so that the minimum lower limit value LS of the light transmittance in the electro-optical devices 4R, 4G, and 4B becomes the lowest limit value L1. A gradation conversion process is performed on the image signal to be changed, and the gradation-light transmittance characteristic curve CS is changed to a gradation-light transmittance characteristic curve C1.
Then, the image signal after the gradation-light transmittance characteristic changing process by the characteristic changing unit 723B is output to each of the liquid crystal panel modules 42R, 42G, and 42B, and each of the liquid crystal panel modules 42R, 42G, and 42B is changed. An optical image is formed in accordance with each gradation-light transmittance characteristic.

  When the duty ratio suppression control (process S5) is performed by the light source drive controller 722 and the gradation-light transmittance characteristic changing process (process S6) is performed by the electro-optical device drive controller 723, the controller 72 Each temperature sensor signal is sequentially input via the sensor signal receiving unit 721 to recognize the temperature of each LED module 2R, 2G, 2B. Here, the control unit 72 compares the highest temperature among the recognized temperatures with the temperature threshold value 2 stored in the duty ratio control data storage unit 732 of the storage unit 73, and among the recognized temperatures. It is determined whether or not the highest temperature is equal to or lower than the temperature threshold 2 (processing S7).

When it is determined as “N” in the process S7, that is, when it is determined that the highest temperature among the recognized temperatures is not equal to or lower than the temperature threshold 2, the duty ratio suppression control (process S5) and the floor described above are performed. The tone-light transmittance characteristic changing process (process S6) is continuously performed.
The duty ratio control unit 722A repeatedly performs the duty ratio suppression control (processing S5) in accordance with the duty ratio suppression control table T2 stored in the storage unit 73, thereby, as shown in FIG. 8, each recognized LED module 2R. , 2G, 2B, the duty ratio once changed is gradually increased, that is, the lighting time per unit time when the LED modules 2R, 2G, 2B are intermittently lit is gradually increased. It is long.
In addition, the characteristic changing unit 723B repeatedly performs the gradation-light transmittance characteristic changing process (processing S6) according to the conversion table stored in the storage unit 73, thereby recognizing each recognized LED module 2R, 2G, 2B. Each gradation-light transmittance characteristic curve is changed so that the lower limit value of the light transmittance in the electro-optical devices 4R, 4G, and 4B becomes smaller as the temperature decreases. For example, referring to FIG. 3, the characteristic changing unit 723B performs the gradation conversion process so that the lowest transmittance value L1 of the light transmittance becomes the lowest limit value L2, and the gradation-light transmittance characteristic. The curve C1 is changed to a gradation-light transmittance characteristic curve C2.

On the other hand, when it is determined as “Y” in the process S7, that is, the duty ratio suppression control (process S5) is repeatedly performed, the temperatures of the LED modules 2R, 2G, and 2B are lowered, and among the recognized temperatures, When it is determined that the highest temperature is equal to or lower than the temperature threshold 2, the control state switching unit 722B outputs a predetermined control command to the duty ratio control unit 722A, and the control state of the duty ratio control unit 722A is changed to the duty ratio. The control is switched from the suppression control to the duty ratio increase control (processing S8).
Then, the duty ratio control unit 722A performs duty ratio increase control of the LED modules 2R, 2G, and 2B (process S9), similarly to the above-described duty ratio increase control (process S2).
In addition, the characteristic changing unit 723B stops performing the gradation conversion process on the image signal output from the image processing unit 723A (processing S10). Then, each liquid crystal panel module 42R, 42G, 42B forms each optical image according to the gradation-light transmittance characteristic curve that has been subjected to the gamma correction processing by the image processing unit 723A.
Similar to the above-described duty ratio increase control (process S2), by performing the duty ratio increase control (process S9), the temperatures of the LED modules 2R, 2G, and 2B rise again as shown in FIG. As described above, in the present embodiment, when the projector 1 is driven, the above-described processing S1 to processing S10 are repeatedly performed.

  In the first embodiment described above, the control state switching unit 722B of the light source drive control unit 722 is configured such that any one of the temperatures of the LED modules 2R, 2G, and 2B detected by the temperature detection sensor 20 is a temperature threshold value. When the ratio exceeds 1, the duty ratio control unit 722A performs the duty ratio suppression control (processing S5) of the LED modules 2R, 2G, and 2B, so that the LED module 2R is compared with the temperature before the temperature exceeds the temperature threshold 1. , 2G, 2B can be reduced, and the temperatures of the LED modules 2R, 2G, 2B can be reduced. Therefore, the temperatures of the LED modules 2R, 2G, and 2B can be set to the temperature threshold value 1 or less, and the temperature rise inside the projector 1 can be suppressed. This also prevents the temperature inside the projector 1 from increasing to an abnormal state, and there is no need to perform control to turn off the power when the internal temperature becomes an abnormal state. Since it does not disappear suddenly, the convenience of the projector 1 can be improved.

  Further, the control state switching unit 722B is configured such that after the temperature of the LED modules 2R, 2G, 2B detected by the temperature detection sensor 20 becomes equal to or lower than the temperature threshold 2, the LED module 2R, 2G, Since the control state of 2B is switched from duty ratio suppression control to duty ratio increase control, after the temperature threshold 2 is reached, the temperature of the projector 1 is less affected by the temperature rise inside the LED module 2R, 2G, 2B. Brightness can be increased and an optical image with good visibility can be projected.

By the way, the LED element which comprises LED module 2R, 2G, 2B has the characteristic that the light quantity inject | emitted changes with the temperature, for example, when the temperature becomes high, the light quantity inject | emitted decreases. Accordingly, the luminance decreases as the driving time of the LED modules 2R, 2G, and 2B elapses.
In the present embodiment, the duty ratio control unit 722A is configured so that the temperature of the LED modules 2R, 2G, and 2B detected by the temperature detection sensor 20 exceeds the temperature threshold 1 and after the temperature threshold 2 or less. Since the duty ratio increase control is performed, the lighting time per unit time of the LED modules 2R, 2G, 2B is gradually increased in accordance with the temperature rise of the LED modules 2R, 2G, 2B, and the LED modules 2R, 2G, 2B It is possible to avoid a decrease in luminance as the driving time elapses and to project an optical image with good visibility.

  Further, when the duty ratio control unit 722A performs the duty ratio suppression control, the duty ratio control unit 722A temporarily changes the duty ratio to a low value according to the temperature drop of the LED modules 2R, 2G, and 2B detected by the temperature detection sensor 20. The ratio is gradually increased, that is, the lighting time per unit time when the LED modules 2R, 2G, and 2B are intermittently turned on is lengthened. Therefore, even when the duty ratio suppression control is performed, the LED modules 2R, 2G , 2B can be gradually increased, and an optical image with good visibility can be projected more quickly.

  And since duty ratio control part 722A performs duty ratio increase control and duty ratio suppression control of each LED module 2R, 2G, and 2B with each duty ratio set up with a predetermined ratio corresponding to predetermined temperature, Each LED module 2R, 2G, 2B can be intermittently lit so as not to change the hue of each color light emitted from each LED module 2R, 2G, 2B.

  In addition, the characteristic changing unit 723B of the electro-optical device drive control unit 723 performs an image signal output from the image processing unit 723A based on the temperatures of the LED modules 2R, 2G, and 2B detected by the temperature detection sensor 20. The gradation conversion process is performed to improve the light transmittance of the electro-optical devices 4R, 4G, and 4B in the low gradation region A of the image signal, and the gradation-light transmittance characteristics of the electro-optical devices 4R, 4G, and 4B are improved. Since each change is made, the light flux absorbed by the electro-optical devices 4R, 4G, and 4B can be reduced, and the heat generation amount of the electro-optical devices 4R, 4G, and 4B can be reduced. Accordingly, by providing both the light source drive control unit 722 and the electro-optical device drive control unit 723, the amount of heat generated by both the light source device 2 and the electro-optical device 4 can be reduced. Temperature rise can be effectively suppressed.

Here, the characteristic changing unit 723 </ b> B is a gradation-light transmittance characteristic based on the temperature detected by the temperature detection sensor 20 when the duty ratio suppression control of the light source device 2 is performed by the light source drive control unit 722. Therefore, a decrease in luminance of the light source device 2 when the duty ratio suppression control of the light source device 2 is performed can be effectively suppressed.
In addition, the characteristic changing unit 723B substantially has each gradation-light transmittance characteristic between the electro-optical devices 4R, 4G, 4B based on the temperatures of the LED modules 2R, 2G, 2B detected by the temperature detection sensor 20. Since each gradation-light transmittance characteristic is changed to be equal, it is possible to improve the color tone of each optical image formed by each electro-optical device 4R, 4G, 4B according to each gradation-light transmittance characteristic. In addition, the optical image synthesized by the cross dichroic prism 5 is enlarged and projected by the projection lens 6, so that a good optical image without color unevenness can be projected.

  Furthermore, since the light source device 2 is composed of LED modules 2R, 2G, and 2B configured to include LED elements, the amount of heat generated during driving is higher than that of a light source device such as a high-pressure mercury lamp or a metal halide lamp. Is small, the temperature rise of the light source device 2 can be further suppressed, and the temperature increase inside the projector 1 can be further suppressed. Further, the power consumption when driving the light source device 2 can be small. Furthermore, intermittent lighting control of the light source device 2 can be easily performed. Furthermore, the light source device 2 can be reduced in size and weight, and as a result, the projector 1 can be reduced in size and weight.

[Second Embodiment]
Next, 2nd Embodiment of this invention is described based on drawing.
In the following description, the same structure and the same members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted or simplified.
In the first embodiment, the light source drive controller 722 intermittently lights each LED module 2R, 2G, 2B so that each color light emitted from each LED module 2R, 2G, 2B has a predetermined hue. The duty ratios of the LED modules 2R, 2G, and 2B are controlled by setting the respective duty ratios to predetermined ratios. In addition, the electro-optical device drive control unit 723 changes each gradation-light transmittance characteristic so that each optical image formed by each electro-optical device 4R, 4G, 4B has a predetermined hue. That is, control is performed to similarly change each duty ratio and each gradation-light transmittance characteristic.
On the other hand, in the second embodiment, each duty ratio and each gradation-light transmittance characteristic can be controlled to be changed independently.

Specifically, FIG. 9 is a block diagram illustrating a control structure of the light source device 2 and the electro-optical device 4 by the control device 8 in the second embodiment.
The control device 8 includes a control unit 82 in addition to the video signal input unit 71 and the storage unit 73 described in the first embodiment.
The duty ratio control data storage unit 732 constituting the storage unit 73 stores a duty ratio increase control table T1, a duty ratio suppression control table T2, and a duty ratio control switching table T3, and a light source drive control described later. The unit 822 stores a predetermined duty ratio threshold when switching from independent duty ratio control to hue duty ratio control.

In addition to the sensor signal receiving unit 721 described in the first embodiment, the control unit 82 can control to independently change each duty ratio when intermittently lighting each LED module 2R, 2G, 2B. A drive control unit 822 and an electro-optical device drive control unit 823 that enables control to independently change each gradation-light transmittance characteristic are provided.
The duty ratio control unit 822A constituting the light source drive control unit 822 is substantially similar to the duty ratio control unit 722A described in the first embodiment, and in accordance with a control command from the control state switching unit 822B, a sensor signal receiving unit 721. Based on the temperature of each LED module 2R, 2G, 2B corresponding to each temperature sensor signal received in step S3 and information stored in the storage unit 73 (duty ratio increase control table T1, duty ratio suppression control table T2). The duty ratio increase control and duty ratio suppression control of the LED modules 2R, 2G, and 2B are performed.
The duty ratio control unit 822A includes a hue duty ratio control that simultaneously performs the above-described duty ratio increase control and duty ratio suppression control for each of the LED modules 2R, 2G, and 2B, and the above-described duty ratio increase control. And independent duty ratio control which implements duty ratio suppression control individually with respect to each LED module 2R, 2G, 2B is implemented.

The control state switching unit 822B constituting the light source drive control unit 822 is substantially similar to the control state switching unit 722B described in the first embodiment, and corresponds to each temperature sensor signal received by the sensor signal receiving unit 721. Based on the temperatures of the LED modules 2R, 2G, and 2B and information (duty ratio control switching table T3) stored in the storage unit 73, the control state (duty ratio increase control, duty ratio suppression control) by the duty ratio control unit 822A ).
In addition, the control state switching unit 822B uses each temperature of each LED module 2R, 2G, 2B corresponding to each temperature sensor signal received by the sensor signal receiving unit 721 and the duty ratio threshold value stored in the storage unit 73. Based on this, the control state (hue duty ratio control, independent duty ratio control) by the duty ratio control unit 822A is switched.

The electro-optical device drive control unit 823 includes a characteristic changing unit 823B in addition to the image processing unit 723A described in the first embodiment.
Similar to the characteristic changing unit 823B described in the first embodiment, the characteristic changing unit 823B performs a gradation conversion process on the image signal output from the image processing unit 723A, and obtains a gradation-light transmittance characteristic. change. Here, when the independent duty ratio control of the LED modules 2R, 2G, and 2B is performed by the light source drive control unit 822, the characteristic changing unit 823B performs the gradation-light corresponding to the electro-optical devices 4R, 4G, and 4B. Change transmittance characteristics independently.

Next, control operations of the light source device 2 and the electro-optical device 4 by the control device 8 in the second embodiment will be described.
FIG. 10 is a flowchart for explaining a control operation by the control device 8.
FIG. 11 is a diagram illustrating an example of a temperature transition of the LED modules 2R, 2G, and 2B under the control of the control device 8. In addition, in FIG. 11, although it has shown as LED module 2B, 2G, 2R in order with high temperature, it is not restricted to this.
FIG. 12 is a diagram illustrating a change in the duty ratio when the LED modules 2R, 2G, and 2B are intermittently turned on under the control of the control device 8. FIG. 12 shows the transition of the duty ratio when intermittently lighting the LED module having the highest temperature, for example, the LED module 2B, among the LED modules 2R, 2G, and 2B.
After the projector 1 is started, as shown in FIG. 11, as the driving time of the projector 1 elapses, the temperatures of the LED modules 2R, 2G, and 2B gradually increase due to the lighting of the LED elements. In such a state, similarly to the process S1 described in the first embodiment, the temperature detection sensors 20R, 20G, and 20B detect the temperatures of the LED modules 2R, 2G, and 2B (process S11: temperature detection). Step).
The light source drive control unit 822 performs duty ratio increase control simultaneously on the LED modules 2R, 2G, and 2B, similarly to the process S2 described in the first embodiment (process S12).
In this process S12, the light source drive control unit 822 performs the hue duty ratio control in order to perform the duty ratio increase control at the same time with each duty ratio set to a predetermined ratio for each LED module 2R, 2G, 2B. doing.

When the duty ratio increase control (process S2) is performed by the light source drive control unit 822, the control unit 82 performs the LED modules 2R, 2G, and 2B in the same manner as the process 3 described in the first embodiment. It is determined whether or not the highest temperature among the temperatures exceeds the temperature threshold 1 (process S13: temperature determination step).
Here, when it is determined as “N” in the process S13, that is, when it is determined that none of the temperatures of the LED modules 2R, 2G, and 2B exceeds the temperature threshold value 1, the duty ratio is increased. Control (processing S12) is continuously performed.
On the other hand, when it is determined as “Y” in the process S13, that is, when it is determined that the highest temperature of the LED modules 2R, 2G, and 2B exceeds the temperature threshold 1, the control state switching unit 822B. Outputs a predetermined control command to the duty ratio control unit 822A, and switches the control state of the duty ratio control unit 822A from the hue duty ratio control (process S12) to the independent duty ratio control (process S14).

After the process S14, the duty ratio control unit 822A performs independent duty ratio control of the LED modules 2R, 2G, and 2B as described below in accordance with the control command from the control state switching unit 822B (process S15). .
First, the control part 82 specifies the LED module corresponding to the temperature which exceeded the temperature threshold value 1 among each LED module 2R, 2G, 2B (process S15A). Hereinafter, the identified LED module is referred to as an LED module 2B.
Then, the duty ratio control unit 822A performs the duty ratio increase control table T1 stored in the duty ratio control data storage unit 732 of the storage unit 73 for the LED modules 2R and 2G other than the LED module 2B specified in the process S15A. As a result, duty ratio increase control is performed (step S15B). For example, in the duty ratio increase control (process S15B), the duty ratio increase control table T1 corresponding to the LED modules 2R and 2G is performed based on the highest temperature among the LED modules 2R and 2G. By performing the duty ratio increase control on the LED modules 2R and 2G in this way, the temperature of the LED modules 2R and 2G even after the temperature of the LED module 2B exceeds the temperature threshold 1 as shown in FIG. Will rise.

On the other hand, for the LED module 2B specified in step S15A, the duty ratio control unit 822A stores the duty ratio suppression control table T2 corresponding to the LED module 2B stored in the duty ratio control data storage unit 732 of the storage unit 73. Therefore, duty ratio suppression control is performed (step S15C). By performing duty ratio suppression control on the LED module 2B in this way, as shown in FIG. 12, the duty ratio when the LED module 2B is intermittently controlled is changed to low, that is, lighting per unit time. Time is shortened. For this reason, as shown in FIG. 11, the temperature of the LED module 2B decreases.
The characteristic changing unit 823B refers to the conversion table corresponding to the LED module 2B, that is, corresponding to the electro-optical device 4B, stored in the gradation-light transmittance characteristic data storage unit 733 of the storage unit 73. Based on the temperature of the LED module 2B, gradation conversion is performed on the image signal corresponding to the electro-optical device 4B output from the image processing unit 723A so that the lower limit value of the light transmittance in the electro-optical device 4B is increased. Processing is performed to change the gradation-light transmittance characteristic corresponding to the electro-optical device 4B (processing S15D). Note that the gradation-light transmittance characteristic changing process is substantially the same as in the first embodiment, and a detailed description thereof will be omitted.

  The control state switching unit 822B uses the duty ratio control unit 822A to increase the duty ratio of the LED modules 2R and 2G (processing S15B), control the duty ratio suppression of the LED module 2B (processing S15C), and perform the electrical operation using the electro-optical device drive control unit 723. When the gradation-light transmittance characteristic changing process (process S15D) corresponding to the optical device 4B is performed, in process S15C, the duty ratio for intermittently lighting the LED module 2B is recognized. Here, the control state switching unit 822B compares the recognized duty ratio with the duty ratio threshold value stored in the duty ratio control data storage unit 732 of the storage unit 73, and whether the recognized duty ratio exceeds the duty ratio threshold value. It is determined whether or not (processing S15E).

When it is determined as “N” in the process S15E, that is, when it is determined that the recognized duty ratio is equal to or less than the duty ratio threshold, the above-described duty ratio increase control of the LED modules 2R and 2G (process S15B), LED The module 2B duty ratio suppression control (process S15C) and the gradation-light transmittance characteristic changing process (process S15D) in the electro-optical device 4B are continuously performed.
As described in the first embodiment, the duty ratio suppression control (processing S15C) is repeatedly performed, so that the duty once changed to a low value as the temperature of the LED module 2B decreases as shown in FIG. The ratio is gradually increased, that is, the lighting time per unit time when the LED module 2B is intermittently lit is gradually increased. In addition, by repeatedly performing the gradation-light transmittance characteristic changing process (process S15D), the lower limit value of the light transmittance in the electro-optical device 4B becomes smaller as the temperature of the LED module 2B decreases. The gradation-light transmittance characteristic curve is changed.

On the other hand, when it is determined as “Y” in the process S15E, that is, the duty ratio when the LED module 2B is intermittently turned on by repeatedly performing the duty ratio suppression control (process S15C) is gradually increased. Is determined to have exceeded the duty ratio threshold value, the control state switching unit 822B outputs a predetermined control command to the duty ratio control unit 822A, and the control state of the duty ratio control unit 822A is controlled by independent duty ratio control (processing S14). ) To hue duty ratio control (step S16).
After the process S16, the duty ratio control unit 822A performs the hue duty ratio control of the LED modules 2R, 2G, and 2B as described below in accordance with the control command from the control state switching unit 822B (process S17). .
The duty ratio control unit 822A continuously performs the above-described duty ratio suppression control (process S15C) for the LED module 2B. Thus, by continuing duty ratio suppression control with respect to LED module 2B, as shown in FIG. 11, the temperature of LED module 2B further reduces. For the LED modules 2R and 2G, the duty ratio suppression control table T2 corresponding to the LED modules 2R and 2G stored in the duty ratio control data storage unit 732 of the storage unit 73 is referred to, and the temperature of the LED module 2B is referred to. Based on the above, the duty ratio suppression control is performed. That is, the duty ratio control unit 822A performs duty ratio suppression control of all the LED modules 2R, 2G, and 2B based on the temperature of the LED module 2B, so that each LED module 2R, 2G, and 2B has a predetermined ratio. Lights intermittently at each duty ratio, and hue duty ratio control is performed. By performing duty ratio suppression control on the LED modules 2R and 2G in this way, the duty ratio when the LED modules 2R and 2G are controlled to be intermittently lighted is changed to low, that is, the lighting time per unit time is short. Become. For this reason, as shown in FIG. 11, the temperature of LED module 2R, 2G reduces.

  At this time, the characteristic changing unit 823B continuously performs the gradation-light transmittance characteristic changing process (process S15D) corresponding to the electro-optical device 4R described above, and also the gradation-light of the storage unit 73. Based on the temperature of the LED module 2B with reference to the conversion table corresponding to the LED modules 2R and 2G, that is, corresponding to the electro-optical devices 4R and 4G, stored in the transmittance characteristic data storage unit 733, the electro-optical device A gradation-light transmittance characteristic changing process corresponding to 4R and 4G is performed. That is, the characteristic changing unit 823B performs the changing process of the gradation-light transmittance characteristics in all the electro-optical devices 4R, 4G, 4B based on the temperature of the LED module 2B, thereby changing each gradation-light. The transmittance characteristic curves are substantially the same. Therefore, when an optical image is formed by each electro-optical device 4R, 4G, 4B according to each gradation-light transmittance characteristic curve, each optical image has a predetermined hue.

The control unit 72 sequentially outputs each temperature sensor signal via the sensor signal receiving unit 721 when the hue duty ratio control (processing S17) is performed by the light source drive control unit 822, and each LED module 2R, 2G. , 2B temperature is recognized. Here, the control unit 72 compares the temperature of the LED module 2B specified in the process S15A with the temperature threshold 2 stored in the duty ratio control data storage unit 732 of the storage unit 73, and the temperature of the LED module 2B is determined. It is determined whether or not the temperature threshold value is 2 or less (processing S18).
When it is determined as “N” in the process S18, that is, when it is determined that the temperature of the LED module 2B is not equal to or lower than the temperature threshold 2, the above-described hue duty ratio control (process S17) is continuously performed.

On the other hand, when it is determined as “Y” in the process S18, that is, by repeatedly performing the hue duty ratio control (process S17), as shown in FIG. 11, the temperature of the LED module 2B further decreases, and the LED module When it is determined that the temperature of 2B is equal to or lower than the temperature threshold 2, the control state switching unit 822B outputs a predetermined control command to the duty ratio control unit 822A, similarly to the process S8 described in the first embodiment. Then, the control state of the duty ratio control unit 822A is switched from the duty ratio suppression control to the duty ratio increase control (process S19).
Then, the duty ratio control unit 822A performs duty ratio increase control of the LED modules 2R, 2G, and 2B (process 20), similarly to the above-described duty ratio increase control (process S12).
Further, the characteristic changing unit 823B stops performing the gradation conversion process on the image signal output from the image processing unit 723A (processing S21).
Similar to the above-described duty ratio increase control (process S12), by performing the duty ratio increase control (process S20), the temperatures of the LED modules 2R, 2G, and 2B rise again as shown in FIG. Thus, in the present embodiment, when the projector 1 is driven, the above-described processing S11 to processing S21 are repeatedly performed.

  In the second embodiment as described above, compared to the first embodiment, the control state switching unit 822B includes the temperature of the LED modules 2R, 2G, and 2B detected by the temperature detection sensor 20. When at least one of the temperatures exceeds the temperature threshold 1, the control state by the duty ratio control unit 822A is switched from the hue duty ratio control to the independent duty ratio control, and the LED module 2R, 2G, 2B is switched to the duty ratio control unit 822A. Among these, the LED module corresponding to at least one of the temperatures is subjected to duty ratio suppression control, and the other LED modules are subjected to duty ratio increase control. Securing each color light emitted from each LED module 2R, 2G, 2B It is possible to suppress a decrease in luminance as a whole when.

  In addition, when the independent duty ratio control by the duty ratio control unit 822A is being performed, the control state switching unit 822B, when the duty ratio of the LED module corresponding to at least one of the temperatures exceeds the duty ratio threshold, Since the independent duty ratio control by the duty ratio control unit 822A is switched to the hue duty ratio control, the brightness of the LED module corresponding to at least one of the temperatures becomes a brightness that has little influence on reducing the brightness of the projected image. By performing duty ratio control, it is possible to project an optical image having a predetermined luminance value and a good color.

  Further, the characteristic changing unit 823B has the at least one of the temperatures of the electro-optical devices 4R, 4G, and 4B when the independent light duty ratio control of the light source device 2 is performed by the light source drive control unit 822. Since the gradation-light transmittance characteristic changing process is performed only for the electro-optical device corresponding to the optical optical device 4R, 4G, 4B, the optical image is applied to each electro-optical device 4R, 4G, 4B corresponding to the different brightness of each LED module Thus, the color balance of the optical image synthesized by the cross dichroic prism 5 can be corrected.

Although the present invention has been described with reference to preferred embodiments, the present invention is not limited to these embodiments, and various improvements and design changes can be made without departing from the scope of the present invention. It is.
In each of the above embodiments, both the duty ratio control of the light source device 2 by the light source drive control units 722 and 822 and the gradation-light transmittance characteristic change control in the electro-optical device 4 by the electro-optical device drive control units 723 and 823 are performed. However, the present invention is not limited to this, and the object of the present invention can be sufficiently achieved even when only one of the controls is performed.

In each of the above embodiments, the light source drive control units 722 and 822 perform duty ratio increase control (processing S2, S9, S12, and S20) before the temperature of the LED modules 2R, 2G, and 2B exceeds the temperature threshold value 1, Although the duty ratio is gradually increased according to the temperature rise of the LED modules 2R, 2G, and 2B, it is not limited to this. For example, when performing duty ratio increase control, it is good also as a structure which implements the control which carries out intermittent lighting of LED module 2R, 2G, 2B continuously with a predetermined | prescribed duty ratio.
In the first embodiment, the light source drive control unit 722 performs duty ratio suppression control after the temperature of the LED modules 2R, 2G, and 2B exceeds the temperature threshold 1, and once changes the duty ratio to be low. From the above, the low-changed duty ratio is gradually increased as the temperature of the LED modules 2R, 2G, and 2B decreases, but the present invention is not limited to this. For example, when the duty ratio suppression control is performed, the duty ratio may be changed to a low value, and then the LED modules 2R, 2G, and 2B may be intermittently turned on at the changed duty ratio. .
A configuration in which the characteristic change units 723B and 823B change the gradation-light transmittance characteristic in accordance with the rise or fall of the temperature of the LED modules 2R, 2G, and 2B when the above control is performed. May be adopted.

In each of the embodiments described above, the characteristic changing units 723B and 823B perform the gradation conversion process on the image signal when changing the gradation-light transmittance characteristic, but the present invention is not limited to this. For example, a predetermined offset voltage is added to the drive voltage applied to the liquid crystal panel constituting the electro-optical device 4, and the drive voltage applied to the liquid crystal panel is shifted to the high voltage side to change the gradation-light transmittance characteristic. It is good also as a structure.
Further, the gradation-light transmittance characteristic may be changed simultaneously with the gamma correction process. In other words, the gradation processing unit 723 </ b> A according to each of the embodiments may perform a gradation-light transmittance characteristic changing process.
In each said embodiment, although the LED element was employ | adopted as a solid light emitting element which comprises the light source device 2, you may employ | adopt not only this but another solid light emitting element, for example, a semiconductor laser.

  In the first embodiment, the temperature detection sensor 20 is configured with three corresponding to the three LED modules 2R, 2G, and 2B. However, the temperature detection sensor 20 is not limited thereto, and at least of the LED modules 2R, 2G, and 2B. What is necessary is just to arrange | position so that the temperature of any LED module may be detected. That is, the temperature detection sensor 20 is not limited to three, and may be one or two.

  In the second embodiment, the hue duty ratio control is switched to the independent duty ratio control based on the highest temperature among the temperatures of the LED modules 2R, 2G, and 2B. However, the present invention is not limited to this. For example, when the largest duty ratio among the respective duty ratios when the LED modules 2R, 2G, and 2B are intermittently turned on exceeds a predetermined duty ratio threshold, the hue duty ratio control is switched to the independent duty ratio control. A configuration may be adopted. In this case, the hue duty ratio control before switching to the independent duty ratio control is a state in which the duty ratio increase control of the LED modules 2R, 2G, and 2B is performed, or the duty ratio suppression control of the LED modules 2R, 2G, and 2B You may be in the state which is implementing.

  In each of the embodiments described above, the control devices 7 and 8 of the projector 1 include the video signal input unit 71 and perform drive control of the electro-optical device 4 according to an image signal input from an external device. Not exclusively. For example, the video signal input unit 71 is omitted, and the control devices 7 and 8 of the projector 1 include an external control input unit that inputs a control signal from an external device, an image data storage unit that stores predetermined image data, A configuration including an image data generation unit that performs predetermined processing on the image data stored in the image data storage unit based on a control signal input by an external control input unit, and drives and controls the electro-optical device 4 It may be.

In each of the above embodiments, the liquid crystal panels constituting the liquid crystal panel modules 42R, 42G, and 42B have been described as transmissive liquid crystal panels. However, the present invention is not limited thereto, and may be configured as a reflective liquid crystal panel. In this case, the gradation-light transmittance characteristic described in the above embodiments is a gradation-light reflectance characteristic, and the characteristic changing units 723B and 823B change the gradation-light reflectance characteristic.
In each of the embodiments described above, the light source device 2 is configured by the three LED modules 2R, 2G, and 2B, and the electro-optical device 4 is configured by the three electro-optical devices 4R, 4G, and 4B. Not limited to this. For example, the light source device 2 has only one LED module, the electro-optical device 4 has only one electro-optical device, the light source device 2 has two LED modules, and the electro-optical device 4 has two electro-optical devices. Alternatively, the light source device 2 may have four or more LED modules, and the electro-optical device 4 may have four or more electro-optical devices.
In each of the above-described embodiments, the electro-optical device 4 is configured to include a liquid crystal panel. However, the present invention is not limited thereto, and may be configured as a digital micromirror device (trademark of Texas Instruments).
In each of the above embodiments, the projector 1 may be configured as a front projection type projector that projects an optical image from the side on which the screen 100 is observed, or projects an optical image from the side opposite to the side on which the screen 100 is observed. You may comprise as a rear projection type projector.

Although the best configuration for carrying out the present invention has been disclosed in the above description, the present invention is not limited to this. That is, the invention has been illustrated and described primarily with respect to particular embodiments, but may be configured for the above-described embodiments without departing from the scope and spirit of the invention. Various modifications can be made by those skilled in the art in terms of materials, quantity, and other detailed configurations.
Therefore, the description limited to the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such is included in this invention.

  The projector of the present invention is useful as a projector used in a home theater or a presentation because it can suppress an increase in internal temperature and improve convenience.

FIG. 2 is a diagram schematically illustrating a schematic configuration of a projector according to the first embodiment. The block diagram which shows the control structure of the light source device and electro-optical apparatus by the control apparatus in the said embodiment. The figure which shows typically the change process of the gradation-light transmittance characteristic by the characteristic change part in the said embodiment. The figure which shows typically the table structure memorize | stored in the duty ratio control data storage part in the said embodiment. The figure which plotted the information memorize | stored in the duty ratio control data storage part in the said embodiment. The flowchart for demonstrating the control action by the control apparatus in the said embodiment. The figure which shows transition of the temperature of the LED module by control of the control apparatus in the said embodiment. The figure which shows transition of the duty ratio at the time of carrying out the intermittent lighting of the LED module by control of the control apparatus in the said embodiment. The block diagram which shows the control structure of the light source device and electro-optical apparatus by the control apparatus in 2nd Embodiment. The flowchart for demonstrating the control action by the control apparatus in the said embodiment. The figure which shows an example of the temperature transition of the LED module by control of the control apparatus in the said embodiment. The figure which shows transition of the duty ratio at the time of carrying out the intermittent lighting of the LED module by control of the control apparatus in the said embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Projector, 2 ... Light source device, 4 ... Electro-optical device, 5 ... Cross dichroic prism (color synthesis optical device), 6 ... Projection lens (projection optical device), 20 ... Temperature detection sensor (temperature detection unit), 722 ... Light source drive control unit, 722A ... Duty ratio control unit, 722B ... Control state switching unit, 723 ... Electro-optical device drive control unit, 723B ..Characteristic change unit, S1, S11... Temperature detection step, S3, S13... Temperature determination step, S5, S15C... Duty ratio suppression control step, S6, S15D.

Claims (16)

A light source device, an electro-optical device that forms an optical image by performing light modulation by changing light transmittance or light reflectance of a light beam emitted from the light source device according to a gradation level of image information, and A projection optical device that magnifies and projects an optical image formed by the electro-optical device,
A light source drive control unit that intermittently controls the light source device, and a temperature detection unit that is disposed near the light source device and detects the temperature of the light source device,
The light source drive control unit includes a duty ratio control unit that performs duty ratio control for intermittently lighting the light source device at a predetermined duty ratio, and a control state switching unit that switches a control state by the duty ratio control unit,
The control state switching unit compares the detected temperature detected by the temperature detecting unit with a predetermined first temperature threshold value, and intermittently turns the light source device on when the detected temperature exceeds the first temperature threshold value. A projector characterized by causing the duty ratio control unit to perform duty ratio suppression control for shortening a lighting time per unit time when lighting. The projector according to claim 1, wherein
The control state switching unit compares the detected temperature detected by the temperature detecting unit with a predetermined second temperature threshold value, and performs the duty ratio suppression control until the detected temperature becomes equal to or lower than the second temperature threshold value. A projector characterized by being implemented by a duty ratio control unit. In the projector according to claim 1 or 2,
The duty ratio control unit is configured to detect the detected temperature before the detected temperature detected by the temperature detecting unit exceeds the first temperature threshold or after the detected temperature becomes equal to or lower than the second temperature threshold. A projector that performs duty ratio increase control for extending a lighting time per unit time when the light source device is intermittently lit according to an increase. The projector according to any one of claims 1 to 3,
The duty ratio control unit, when performing the duty ratio suppression control, intermittently lights the light source device at a predetermined duty ratio that shortens the lighting time per unit time, and detects the temperature detected by the temperature detecting means The predetermined duty ratio is changed so that the lighting time per unit time is lengthened according to the decrease of the projector, and the light source device is intermittently lit with the changed duty ratio. The projector according to any one of claims 1 to 4,
The light source device includes a plurality of light sources that can emit a plurality of colored lights,
The temperature detection unit is configured in a plurality corresponding to the plurality of light source devices,
Each duty ratio when intermittently lighting the plurality of light source devices is set to a predetermined ratio,
The said duty ratio control part implements the hue duty ratio control which performs intermittent lighting control of these light source devices with each duty ratio set to the predetermined ratio. The projector according to any one of claims 1 to 4,
The light source device includes a plurality of light sources that can emit a plurality of colored lights,
The temperature detection unit is configured in a plurality corresponding to the plurality of light source devices,
Each duty ratio when intermittently lighting the plurality of light source devices is set to a predetermined ratio,
The duty ratio control unit performs a hue duty ratio control for intermittently lighting the plurality of light source devices at each duty ratio set to the predetermined ratio,
The control state switching unit is configured to control the hue duty ratio control by the duty ratio control unit based on a plurality of detected temperatures detected by the plurality of temperature detection units, independently of the set predetermined ratio. A projector characterized by switching to independent duty ratio control for intermittent lighting control of the plurality of light source devices with a duty ratio. The projector according to claim 6, wherein
The control state switching unit, when the detected temperature of at least one of the plurality of detected temperatures detected by the plurality of temperature detection units exceeds the first temperature threshold, the hue duty by the duty ratio control unit. The ratio control is switched to the independent duty ratio control, and the duty ratio control unit performs the duty ratio suppression control only for the light source device corresponding to the detected temperature of at least one of the plurality of light source devices. Projector. The projector according to claim 7, wherein
When performing the duty ratio suppression control, the duty ratio control unit intermittently lights the light source device at a predetermined duty ratio that shortens the lighting time per unit time, and detects the detected temperature detected by the temperature detecting means The predetermined duty ratio is changed so as to increase the lighting time per unit time according to the decrease of the light source device, the light source device is intermittently lit at the changed duty ratio,
The control state switching unit compares the duty ratio of the light source device corresponding to the at least one detected temperature with a predetermined duty ratio threshold when the independent duty ratio control is performed by the duty ratio control unit. The projector switches the independent duty ratio control by the duty ratio control unit to the hue duty ratio control when the duty ratio exceeds the duty ratio threshold. The projector according to any one of claims 1 to 8,
An electro-optical device drive control unit for driving and controlling the electro-optical device;
The electro-optical device drive control unit performs predetermined processing on the image information, and a gradation level of the image information and a gradation-light transmittance characteristic or level in light transmittance or light reflectance of the electro-optical device. It is configured to include a characteristic changing unit that changes the tone-light reflectance characteristic,
The characteristic changing unit sets a minimum lower limit value of the light transmittance or light reflectance of the electro-optical device based on the detected temperature detected by the temperature detection unit, and sets the lower limit value and the electric power lower limit value. A projector, wherein the gradation-light transmittance characteristic or the gradation-light reflectance characteristic is changed based on a maximum value of light transmittance or light reflectance of an optical device. The projector according to claim 9, wherein
When the duty ratio suppression control of the light source device is performed by the light source drive control unit, the characteristic change unit is configured to perform the gradation-light transmittance characteristic based on the detected temperature detected by the temperature detection unit or A projector characterized by changing the gradation-light reflectance characteristic. A light source device, an electro-optical device that forms an optical image by performing light modulation by changing light transmittance or light reflectance of a light beam emitted from the light source device according to a gradation level of image information, and A projection optical device that magnifies and projects an optical image formed by the electro-optical device,
An electro-optical device drive control unit that drives and controls the electro-optical device; and a temperature detection unit that is disposed near the light source device and detects the temperature of the light source device.
The electro-optical device drive control unit performs predetermined processing on the image information, and a gradation level of the image information and a gradation-light transmittance characteristic or level in light transmittance or light reflectance of the electro-optical device. It is configured to include a characteristic changing unit that changes the tone-light reflectance characteristic,
The characteristic changing unit sets a minimum lower limit value of the light transmittance or light reflectance of the electro-optical device based on the detected temperature detected by the temperature detection unit, and sets the lower limit value and the electric power lower limit value. A projector, wherein the gradation-light transmittance characteristic or the gradation-light reflectance characteristic is changed based on a maximum value of light transmittance or light reflectance of an optical device. The projector according to any one of claims 9 to 11,
The light source device includes a plurality of light sources that can emit a plurality of colored lights,
The temperature detection unit is configured in a plurality corresponding to the plurality of light source devices,
The electro-optical device includes a plurality of light source devices corresponding to the plurality of light source devices,
A color synthesizing optical device that synthesizes and emits an optical image for each color light formed by the plurality of electro-optical devices;
The characteristic changing unit performs a predetermined process on the image information corresponding to the plurality of color lights based on a plurality of detected temperatures detected by the plurality of temperature detecting units, A projector characterized by changing the tone-light transmittance characteristic or each gradation-light reflectance characteristic to be substantially equal. The projector according to any one of claims 9 to 11,
The light source device includes a plurality of light sources that can emit a plurality of colored lights,
The temperature detection unit is configured in a plurality corresponding to the plurality of light source devices,
The electro-optical device includes a plurality of light source devices corresponding to the plurality of light source devices,
A color synthesizing optical device that synthesizes and emits an optical image for each color light formed by the plurality of electro-optical devices;
The characteristic changing unit performs predetermined processing on the image information corresponding to the plurality of color lights based on a plurality of detected temperatures detected by the plurality of temperature detecting units, and each of the plurality of electro-optical devices is connected to each floor. A projector characterized by changing the tone-light transmittance characteristic or each gradation-light reflectance characteristic to be substantially different. The projector according to any one of claims 1 to 13,
The projector is characterized in that the light source device includes a solid light emitting element. A light source device, an electro-optical device that forms an optical image by performing light modulation by changing light transmittance or light reflectance of a light beam emitted from the light source device according to a gradation level of image information, and A projection optical device that enlarges and projects an optical image formed by the electro-optical device, a light source drive control unit that controls intermittent lighting of the light source device, and a temperature that is disposed in the vicinity of the light source device and detects the temperature of the light source device A projector control method comprising a detection unit,
A temperature detecting step in which the temperature detecting unit detects the temperature of the light source device; and
A temperature determining step in which the light source drive control unit compares the detected temperature detected in the temperature detecting step with a predetermined first temperature threshold value to determine whether the detected temperature exceeds the first temperature threshold value; ,
When the light source drive control unit determines that the detected temperature exceeds the first temperature threshold in the temperature determination step, the lighting time per unit time when the light source device is intermittently turned on is shortened. A projector control method comprising: a duty ratio suppression control step for controlling intermittent lighting of the light source device. A light source device, an electro-optical device that forms an optical image by performing light modulation by changing light transmittance or light reflectance of a light beam emitted from the light source device according to a gradation level of image information, and A projection optical device that magnifies and projects an optical image formed by the electro-optical device, an electro-optical device drive control unit that drives and controls the electro-optical device, and a temperature of the light source device that is disposed near the light source device A temperature control unit for controlling a projector,
A temperature detecting step in which the temperature detecting unit detects the temperature of the light source device; and
The electro-optical device drive control unit performs predetermined processing on the image information based on the detected temperature detected in the temperature detection step, and the gradation level of the image information and the light transmittance of the electro-optical device or And a characteristic changing step for changing a gradation-light transmittance characteristic or a gradation-light reflectance characteristic in light reflectance,
The characteristic changing step sets a minimum lower limit value of the light transmittance or light reflectance of the electro-optical device based on the detection temperature, and sets the lower limit value and the light transmittance or light of the electro-optical device. A projector control method, wherein the gradation-light transmittance characteristic or the gradation-light reflectance characteristic is changed based on a maximum value of reflectance.

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