JP4994806B2 - Image projection apparatus and image projection system - Google Patents

Description

  The present invention relates to an image projection apparatus and an image projection system that project an image according to an image signal from an image supply apparatus via an optical system.

  2. Description of the Related Art Conventionally, in an image projection apparatus such as a projector, a method has been adopted in which information relating to the state of the image projection apparatus is input to an image supply apparatus such as a video deck and an image signal output from the image supply apparatus is corrected. In order to realize this method, for example, a plug and play mechanism is incorporated, and communication is performed between the projector and the VCR via a DDC (Display Data Channel) interface standardized by VESA. ing.

  So-called EDID (Extended Display Identification Data) information is generally used as information indicating the product information of the image projection apparatus and the current setting state. This EDID information is normally stored in a nonvolatile memory of the image projection apparatus.

  For example, as shown in FIG. 11, the optical system of the image projection apparatus includes an illumination optical system 100 having a light source 100a, a color separation / synthesis optical system 101, and a projection optical system 102. In the color separation / synthesis optical system 101, generally only RGB color light is extracted from the illumination light from the illumination optical system 100. Further, in the color separation / synthesis optical system 101, each color light is incident on a reflective image display element provided for each color light to modulate the polarization state, and the color light (modulated light) reflected by the image display element is synthesized. Is done. Then, the color light synthesized by the color separation / synthesis optical system 101, that is, image light is projected from the projection optical system 102, and an image is displayed on the screen S.

  The image projection apparatus is required to be able to project a bright image and to have a wide reproduction color gamut of the projection image. The brightness is increased by using as much light in the visible range as possible contained in the illumination light, that is, by using it over a wide wavelength range. The reproduction color gamut is widened by narrowing the wavelength range of each color light to increase the color purity. Therefore, the brightness and the reproduction color gamut are in a trade-off relationship in which the reproduction color gamut is narrowed when the brightness is increased, and the brightness is lowered when the reproduction color gamut is widened.

  In order to eliminate this trade-off relationship, an image projection apparatus including a movable optical filter is used. The optical filter has a function of cutting a specific wavelength region of illumination light so that the color purity of each color light is high.

  FIG. 12 schematically shows the configuration of an image projection apparatus using an optical filter. The image projection apparatus shown in this figure is obtained by adding an optical filter 103 and its drive mechanism to the image projection apparatus shown in FIG. As shown in the figure, the movable optical filter 103 is configured to be driven to a position on the optical path of illumination light (solid line in the figure) and a position not on the optical path of illumination light (dotted line in the figure). Yes. In other words, the optical filter 103 can be inserted into and removed from the optical path. A motor 104 is used as the drive source.

  FIG. 13 is a block diagram showing the internal structure of the image projection apparatus. This image projection apparatus has a function of transmitting EDID information stored in the memory 105 to the image supply apparatus side via the interface connector 106. Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique of using a display operating time information as one of EDID information, estimating aging deterioration with the personal computer from the information, and selecting a color conversion ICC profile.

  However, in the image projection apparatus disclosed in Patent Document 1, no consideration has been given to the change (mode change) of the state of the image projection apparatus, for example, the position of the optical filter described above. This is because the optical filter 103 shown in FIG. 12 has different color gamut information between the first mode positioned on the optical path and the second mode not positioned on the optical path. For example, when there is no EDID information in the second mode and only EDID information in the first mode exists, the image supply apparatus recognizes that it is in the first mode in the second mode, so that it corresponds to the color gamut of the first mode. Therefore, the image information is output and the image is displayed inappropriately.

As a technique that can solve this problem, a technique that rewrites EDID information when power is turned on in a display having a rewritable memory in which EDID information is stored is known. More specifically, a technique for rewriting the EDID information in the rewritable memory provided in the display when the personal computer recognizes that the display specification has been changed is disclosed (for example, see Patent Document 2). Using this technique, a suitable image can be obtained by rewriting EDID information every time the position of the optical filter changes in FIG.
JP 2003-271116 A JP 2000-194346 A

  However, the apparatus described in Patent Document 2 described above has a problem that the EDID information becomes inappropriate when there is an electrical interruption during rewriting of the EDID information. For example, checksum information for soft error detection such as bit inversion is prepared as one of the EDID information, but the checksum information becomes invalid when rewriting of the EDID information is forcibly terminated halfway. There was a case. Therefore, there is a possibility that the EDID information stored on the display side cannot be recognized from the personal computer side. As a cause of the disconnection of electricity, for example, contact failure occurs in the DDC interface due to external factors such as impact and load.

  Note that a nonvolatile memory such as an EEPROM usually has a limit on the number of times of writing. Therefore, when mode switching occurs frequently, the number of times of writing to the nonvolatile memory may reach the limit.

  Accordingly, an object of the present invention is to provide an image projection apparatus and an image projection system that are highly reliable against external factors such as impact and load.

An image projection apparatus according to an aspect of the present invention is connectable to an image supply apparatus that receives an information unit based on a change in the level of a connection signal, and an image corresponding to the image signal from the image supply apparatus is optically an image projection apparatus that projects through the system, and an optical filter that is movable relative to the optical system, the information unit including information component corresponding to the position of the optical filter, the serial to each position of said optical filter A plurality of stored memories and a memory storing an information unit including an information component corresponding to the position of the optical filter is selected from the plurality of memories, and the information unit is selected from the selected memory as the image. having a selection means for outputting to the supply device, in response to the selection of the memory by the selection means, a control means for changing the level of the connection signal to the image supply device And features.

An image projection system according to one aspect of the present invention receives an image projection apparatus according to one aspect of the present invention and the information unit output from the image projection apparatus based on a connection signal from the image projection apparatus. And an image supply device that supplies an image signal corresponding to the information unit to the image projection device.

  Hereinafter, the present invention will be clarified by preferred embodiments described with reference to the accompanying drawings.

  According to the present invention, since the EDID information corresponding to the state of the image projection apparatus is used, the work of rewriting the EDID information becomes unnecessary. Therefore, it is possible to provide an image projection apparatus and an image projection system with high reliability against external factors such as impact and load.

  Hereinafter, an aspect of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows an embodiment of the image projection system of the present invention. This image projection system is configured by connecting an image supply device 1 that outputs an image signal and an image projection device 2 to which the image signal is supplied from the image supply device 1. Examples of the image supply device 1 include a personal computer, a video deck, a DVD deck, a digital camera, a digital video camera, and a mobile phone.

  The image projection apparatus 2 is an apparatus for displaying an image on a screen by projecting an image, and is generally called a projector. Examples of the projector include a liquid crystal projector and a projector using a digital micromirror device. As the screen, a projector screen, an inner wall of a building, a wall surface of a building, or the like can be used.

  FIG. 2 is a block diagram showing an internal structure of an embodiment of the image projection apparatus of the present invention. The image projection apparatus 2 is a type of apparatus that projects an image from the projection optical system 3. Then, by projecting on the screen S, the viewer can clearly see the image. The image projection device 2 is provided with an interface connector 4 for electrical connection with the image supply device 1. As the interface connector 4, a digital signal DVI (Digital Visual Interface) connector or an HDMI (High-Definition Multimedia Interface) connector can be used. If the signal input to the image projection apparatus is not a digital signal but an analog signal, various analog signal connectors may be used.

  The interface connector 4 is provided with a terminal 4a for inputting a digital image signal, a DDC terminal 4b for transmitting EDID information which is an information unit of the image projection apparatus 2, and a hot plug detection terminal 4c. Yes. In this application, an information unit refers to a group of information that represents an attribute or state of a device. A specific example of EDID information will be described later.

  The DDC terminal 4b can be connected to either one of the two memories 51 and 52 in which EDID information including an information component corresponding to the position of the optical filter 7 is stored differently for each position. ing. As the memory, a mask ROM, PROM, EPROM or the like which is a nonvolatile memory is used. Selection of the memories 51 and 52 for acquiring the EDID information is performed by the switch 6 and the microcomputer 8 which are selection means.

  The selection unit reads out EDID information including an information component corresponding to the position of the optical filter 7 movable with respect to the optical path in the image projection apparatus 2 from the memory 51 or 52 and outputs the EDID information to the image supply apparatus 1. Therefore, the selection unit selects the memory 51 or 52 in which the information unit including the information component corresponding to the position of the optical filter 7 is stored from the two memories 51 and 52, and selects the memory 51 or 52 from the selected memory 51 or 52. It has a function of causing the image supply device 1 to output EDID information. That is, the memory 51 or 52 is selected according to the set mode (here, the first mode or the second mode). The switch 6 is switched by the microcomputer 8.

  The hot plug detection terminal 4 c is connected to the microcomputer 8. The terminal 4c is for detecting that the image supply device 1 and the image projection device 2 are connected to each other.

  The image projection apparatus 2 is provided with a keypad 9 and is connected to the microcomputer 8. The keypad 9 is provided for receiving various key operations by the user of the image projection system. The keypad 9 includes a power button for turning on or off the power of the image projection apparatus 2, a menu button for displaying a menu screen on the screen, and up / down / left / right buttons for selecting a menu. . Whether or not each button has been pressed is determined, for example, by performing a polling process. Here, the polling process is a process of periodically monitoring the presence or absence of an input signal and performing the next process when an input signal is detected.

  A terminal 4 a for inputting a digital image signal is electrically connected to the decoder 10. A digital image signal is input to the decoder 10 from the image supply device 1 via the terminal 4a. The decoder 10 performs a process of decoding the encoded data based on a certain rule and extracting the original data. Specifically, the digital image signal from the terminal 4 a is changed to a TTL level digital image signal that can be handled by the subsequent image processing unit 11. For the decoder 10, for example, a TMDS (Transition Minimized Differential Signaling) type digital video signal receiving circuit is used. If the signal input to the image projection apparatus is an analog video signal, an NTSC, PAL, or SECAM video decoder or analog / digital converter may be used as the decoder 10.

  The image processing unit 11 performs various image processing such as resolution conversion, frame rate conversion, contrast / brightness adjustment, color space conversion, gamma conversion, OSD processing for superimposing menus, and the like on the input digital image signal. These image processes are controlled by the microcomputer 8.

  The panel driver 12 D / A converts the input digital image signal and drives an RGB image display element (not shown) included in the color separation / synthesis optical system 13 based on the converted analog image signal. . Examples of the image display element include a reflective liquid crystal panel (see, for example, JP-A-2003-161917), a transmissive liquid crystal panel, or a micromirror device.

  Here, in the case of the color separation / synthesis optical system 13 using a reflective liquid crystal panel, incident light is separated into red light (R light), green light (G light), and blue light (B light). Then, the polarization state is modulated based on the output of the panel driver 12 by the three reflective liquid crystal panels of RGB, and the reflected light is synthesized.

  The light source 14a provided in the illumination optical system 14 emits light that illuminates the image display element. For example, an ultrahigh pressure mercury lamp or the like is used as the light source 14a. In the illumination optical system 14, the light emitted from the light source 14a is converted into parallel light through a collimator lens, and wavelength components other than the visible range are cut.

  FIG. 3 is a block diagram showing the internal structure of an embodiment of the image supply apparatus 1. The image supply device 1 is connected to the image projection device 2 via an interface connector 4. A CPU 16 is mounted on the computer circuit board in the image supply apparatus 1. The CPU 16 receives input information from the input device 17 via the bus. The CPU 16 communicates with the hard disk 18, ROM 19, RAM 20, and graphics controller 21 via the bus.

  Here, the input device 17 is a keyboard, a mouse, or another operation device. The hard disk 18 stores an OS (Operation System), application program code, data for executing the program code, and the like. The ROM 19 stores a program code that is executed first when the power is turned on, device information of the image supply device 1, and the like. The RAM 20 serves as a work area when computer processing by the CPU 16 is executed.

  Then, the graphics controller 21 generates image data in accordance with the graphics display request from the CPU 16 and transmits it to the color space correction unit 22. The color space correction unit 22 corrects the image data by adding the color gamut information of the image projection apparatus 2 transmitted from the DDC communication unit 24 described later to the image data from the graphics controller 21. Then, the image data is transmitted from the color space correction unit 22 to the transmitter 23. The transmitter 23 converts the image data into a DVI format, and sends a digital image signal to the image projection apparatus 2 side.

  The DDC communication unit 24 can be connected to the DDC terminal 4 b and the terminal 4 c, and a communication line is formed between the DDC communication unit 24 and the interface connector 4. Further, when the hot plug detection signal changes from the LOW level to the HIGH level, the DDC communication unit 24 recognizes that the image supply device 1 and the image projection device 2 are connected to each other. Then, the EDID information stored in the memory 51 or 52 of the image projection apparatus 2 is received via the DDC terminal 4b. Then, the color gamut information included in the EDID information is transmitted to the color space correction unit 22. The above is the main internal structure in the image supply apparatus 1.

  When the power supply is turned on when using the image supply apparatus 1, the program code stored in the ROM 19 is executed by the CPU 16, and the program code stored in the hard disk 18 is executed by the code. Then, the CPU 16 generates graphics according to the program code stored in the hard disk 18 and requests the graphics controller 21 to display the graphics.

  FIG. 4 shows the wavelength distribution of illumination light from the illumination optical system 14. As shown in the figure, in the illumination optical system 14 of the present embodiment, wavelength components other than the visible range are cut, but the wavelength width of the illumination light after the cut is about 420 nm to 680 nm. The intensity of light in the wavelength region near 500 nm is low, and the intensity of light in the wavelength region near 540 nm is maximum. The illumination light from which wavelength components other than the visible light are cut is incident on the optical filter 7, and the specific wavelength region is further cut. The transmittance characteristics of the optical filter 7 are shown in FIG. As shown in the figure, the optical filter 7 cuts yellow-green light in a wavelength range from about 570 nm to about 590 nm.

  The motor 15 shown in FIG. 2 inserts and removes the optical filter 7 between the illumination optical system 14 and the color separation / synthesis optical system 13 in accordance with instructions from the microcomputer 8. More specifically, the optical filter 7 is moved to a position on the optical path of the illumination light and a position not on the optical path of the illumination light by driving the motor 15 and rotating the connecting arm connected to the motor 15. Is possible. By changing the arrangement, switching between two modes in which the positions of the optical filter 7 are different from each other is performed. In other words, switching between the first mode in which the optical filter 7 is positioned on the optical path and the second mode in which the optical filter 7 is not positioned on the optical path is performed.

  FIG. 6 shows the wavelength distribution of green light (G light) with and without the optical filter 7 on the optical path of the illumination light. When the optical filter 7 is not present, the wavelength range is from about 490 nm to about 590 nm. When the optical filter 7 is present, the wavelength range is changed from about 490 nm to about 570 nm. That is, the lower limit side of the wavelength range does not change, but the upper limit side is smaller. More specifically, yellow-green light in the wavelength range of about 570 nm to 590 nm is cut, and the purity of green is increased.

  FIG. 7 shows the color gamut of the combined light when the optical filter 7 is disposed on the optical path and when the optical filter 7 is not disposed on the optical path. This figure shows an xy chromaticity diagram by the CIE (International Commission on Illumination), and the color components x and y excluding the lightness Y in the xyY color system are mapped on a two-dimensional plane. In the figure, a solid color region indicating a horseshoe shape indicates a visible color gamut. Further, the peripheral direction of the horseshoe shape in the figure shows the hue, and the closer to the outer periphery, the higher the saturation. In FIG. 7, the area of the triangle indicating the width of the color gamut is larger when the optical filter 7 is provided.

  The combined light output from the color separation / synthesis optical system 13 illustrated in FIG. 2 is enlarged and projected by the projection optical system 3 and displayed on the external screen S as an output image. The memory 51 stores EDID information when the optical filter 7 is arranged on the optical path of the illumination light. The memory 52 stores EDID information when the optical filter 7 is not disposed on the optical path of the illumination light.

  As shown in FIG. 8, the EDID information includes a manufacturer code, a product code, a serial number, a manufacturing week, a manufacturing year, an EDID version, an EDID revision, video input definition information, an image maximum horizontal size, and an image maximum vertical size. , Information components such as the color gamut value of each color are included. Also, the EDID information includes a checksum information component added so that a value obtained by summing the entire EDID information in bytes is divisible by 256. Here, the information on the color gamut value of each color is an information component corresponding to the position of the optical filter 7. The EDID information includes a value related to the color gamut represented by the xy value, but this value and the checksum are different between the memories 51 and 52.

  Next, control of the image projection system by the microcomputer 8 will be described. First, when it is detected that the power button of the keypad 9 has been pressed from a standby state in which no image is projected, each unit such as the decoder 10, the image processing unit 11, and the panel driver 12 is initialized. As an initial state, the switch 6 is controlled to select the memory 51, and the motor 15 is driven to place the optical filter 7 on the optical path. By doing in this way, yellowish green light is further cut from the illumination light of only visible light, color purity is raised, and it will be in the state which can project an image with a wide reproduction color gamut.

  Further, from this state, when the microcomputer 8 detects that the power button has been pressed again, this time, on the contrary, the end processing is performed in each part. This returns to the standby state where no image is projected.

  Normally, when it is detected that the menu button on the keypad 9 is pressed in the projected state, the menu image A1 is superimposed on the display image A as an OSD image, and various settings can be made by user operations (see FIG. 10). . The processing flow at this time is shown in FIG.

  FIG. 9 shows the flow of OSD image processing. First, in step S1, the microcomputer 8 instructs the image processing unit 11 to display a menu, and the image processing unit 11 superimposes the menu signal on the image signal. FIG. 10 shows an example of a projected image after the menu signal is superimposed. As shown in the figure, the menu image A1 is superimposed on the display image A by the OSD function.

  As described with reference to FIG. 2, the digital image signal output from the decoder 10 is input to the image processing unit 11, and part of the processing in the image processing unit 11 is performed on three rows in the menu image A <b> 1. This is done by the setting unit. Specifically, a color mode setting unit A2, a brightness setting unit A3, and a contrast setting unit A4. The color mode setting unit A2 includes a “color priority” option and a “luminance priority” option. When “Color priority” is selected, the color gamut is wider and the brightness is higher when “Color priority” is selected than when “Brightness priority” is selected. Becomes weaker. In addition, in the brightness setting section A3 and the contrast setting section A4, brightness and contrast setting values are displayed as bar graphs and numerical values, respectively.

  In addition, any one of the color mode setting unit A2, the brightness setting unit A3, and the contrast setting unit A4 can be activated, and a triangle mark is displayed on the left side of the active portion. . In FIG. 10, the color mode setting unit A2 is active.

  In step S2, it is determined whether or not the selection menu should be changed. Specifically, when the upper button or the lower button is pressed on the keypad 9, it is determined that the selection menu is changed. When the selection menu is changed in the upward or downward direction, the upper or lower setting unit is activated in step S3, and the process returns to step S1 to redraw the menu. When the color mode setting unit A2 is in an active state, the upper setting unit indicates the contrast setting unit A4, and the lower setting unit indicates the brightness setting unit A3.

  If it is not determined that the selected menu is changed, it is determined in step S4 whether or not there is a menu-off determination. Specifically, when the menu button is pressed on the keypad 9, it is determined that there is a request for menu off. In this case, in step S5, the menu image displayed on the OSD screen is deleted. Then, the menu is ended and the normal projection state is restored.

  If there is no menu-off request, it is determined in step S6 whether or not there is a request to change brightness / contrast. It is determined that there is a change request when the left button or the right button is pressed on the keypad 9 when one of the brightness setting unit A3 and the contrast setting unit A4 is active. . Increase or decrease the set value with the right or left button. Here, when the right button is pressed once, the set value increases by one, and when the left button is pressed once, the set value decreases by one. When this setting value is large, the brightness is high and the contrast is large. On the other hand, when the set value is small, the brightness is weak and the contrast is small.

  When there is a request for changing the setting value of brightness or contrast, in step S7, the microcomputer 8 instructs the image processing unit 11 to change the brightness or contrast, and the brightness or contrast is changed. Done. Thereafter, the process returns to step S1 and the menu image is redrawn.

  On the other hand, if there is no request for changing the setting value of brightness or contrast, it is determined in step S8 whether or not there is a request for changing the color mode. It is determined that there is a change request when the right button or the left button is pressed on the keypad 9 when the color mode setting unit A2 is active. Specifically, when the right button is pressed when the current state is “color priority”, the color mode setting is changed to “luminance priority”. On the other hand, if the left button is pressed when the current state is “luminance priority”, the color mode setting is changed to “color priority”. Even if the left button is pressed when the current state is “color priority”, or the right button is pressed when the current state is “luminance priority”, the color mode setting is not changed.

  If there is no color mode change request, the process returns to step S1 and the menu image is redrawn. On the other hand, when there is a request for changing the color mode, drive control of the motor 15 is performed in step S9. If the new setting is “color priority”, the optical filter 7 is disposed at a position where the illumination light is filtered, and if “luminance priority”, the optical filter 7 is disposed at a position where the illumination light is not filtered.

  Next, in step S10, the switch 6 is controlled. Specifically, if the new setting is “color priority”, the switch 6 is switched to the memory 51 side, and if it is “luminance priority”, the switch is switched to the memory 52 side. At this time, the operation of dropping the hot plug detection line of the interface connector 4 to the LOW level once by the microcomputer 8 and returning to the HIGH level again may be performed. If it does in this way, the image supply apparatus 1 will recognize that the image projection apparatus 2 was reconnected, and the image supply apparatus 1 will read EDID information again. After the process of step S10 is completed, the process returns to step S1 and the menu image is redrawn.

  According to the above-described embodiment, since EDID information corresponding to the state of the image projection device 2, that is, the position of the optical filter 7, is used, the work of rewriting the EDID information when the optical filter 7 is inserted or removed becomes unnecessary. Therefore, it is possible to provide the image projection apparatus 2 having high reliability against external factors such as impact and load. Further, it is possible to provide the image projection apparatus 2 in which the number of times of writing to the memories 51 and 52 does not reach the limit.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  For example, in the above-described embodiment, the example in which the first mode in which the optical filter 7 is located on the optical path of the optical system and the second mode in which the optical filter 7 is not located on the optical path of the optical system has been described. The present invention is not limited to this. For example, when there are a plurality of optical filters 7 having different characteristics, three or more modes are provided such as a plurality of states in which the optical filters 7 are arranged on the optical path and a state in which none of the optical filters 7 is arranged on the optical path. May be.

It is explanatory drawing which shows one Embodiment of the image projection system of this invention. It is a block diagram which shows the internal structure of one Embodiment of the image projector of this invention. It is a block diagram which shows the internal structure of one Embodiment of the image supply apparatus of this invention. It is explanatory drawing which shows wavelength distribution of the illumination light from an illumination optical system. It is explanatory drawing which shows the transmittance | permeability characteristic of an optical filter. It is explanatory drawing which shows the wavelength distribution of the green light (G light) with the case where an optical filter is on the optical path of illumination light, and the case where it does not exist. It is explanatory drawing which shows the color gamut of the synthetic | combination light with the case where an optical filter is arrange | positioned on an optical path, and the case where an optical filter is not arrange | positioned on an optical path. It is explanatory drawing which shows an example of the EDID information memorize | stored in memory. It is explanatory drawing which shows the flow of a process of an OSD image. It is explanatory drawing which shows an example of an OSD screen. It is explanatory drawing which shows the conventional image projection apparatus. It is explanatory drawing which shows the conventional image projector (with an optical filter). It is a block diagram which shows the structure inside the image projector of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image supply apparatus 2 Image projection apparatus 51,52 Memory 6 Switch 7 Optical filter

Claims (7)

An image projection device that can be connected to an image supply device that receives an information unit based on a change in the level of a connection signal and projects an image according to an image signal from the image supply device via an optical system. ,
An optical filter movable with respect to the optical system;
Information unit including information component corresponding to the position of the optical filter, a plurality of memory memorize for each position of said optical filter,
Selection means for selecting a memory storing an information unit including an information component corresponding to the position of the optical filter from the plurality of memories, and outputting the information unit from the selected memory to the image supply device; ,
An image projection apparatus comprising: control means for changing a level of the connection signal to the image supply apparatus according to selection of a memory by the selection means . 2. The image projection apparatus according to claim 1, wherein the control unit drops the connection signal to a LOW level and returns it to a HIGH level again in response to selection of a memory by the selection unit. The image projection apparatus has a plurality of modes in which the positions of the optical filters are different from each other,
It said selection means, the image projection apparatus according to claim 1 or 2, characterized in that selects the memory in accordance with the set mode. A first mode in which the optical filter is located on an optical path of the optical system;
A second mode in which the optical filter is not positioned on the optical path of the optical system;
The image projection apparatus according to claim 3 , further comprising: Wherein the memory image projection apparatus according to any one of claims 1 to 4, characterized in that it is a non-volatile memory. It said information unit, the image projection apparatus according to any one of claims 1 to 5, characterized in that the EDID information. An image projection device according to any one of claims 1 to 6 ,
An image supply device that receives the information unit output from the image projection device based on a connection signal from the image projection device and supplies an image signal corresponding to the information unit to the image projection device. Image projection system.