JP2006349713A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector capable of inserting a light shielding member for scanning illumination light under less limitation and capable of reducing noise and attaining high-contrast display. <P>SOLUTION: A stripe-like first transmissive pattern image PA1 can be formed in an image area of a liquid crystal display panel 31 in each line of a scanning electrode and a second transmissive pattern image PA2 in which the bright-dark patterns of the first transmissive pattern image PA1 are replaced can be also formed. The inverted first transmissive pattern image PA1 or the inverted second transmissive pattern image PA2 is projected to the image areas of respective liquid crystal display panels 51b, 51g, 51r. When the transmissive pattern images PA1, PA2 are alternately projected correspondingly to frames displayed on respective liquid crystal display panels 51b, 51g, 51r in suitable timing, intermittent illumination of respective liquid crystal display panels 51b, 51g, 51r can be attained and an effect for preventing blur in a moving image can be obtained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projector that projects an image using a liquid crystal display panel or other light modulation device.

  In a general projector, a liquid crystal display panel used as a light modulation device is a hold-type display device. Therefore, unlike a CRT that is an impulse-type display device, a smooth moving image display is performed due to a so-called tailing phenomenon. There is a tendency that it cannot be obtained.

  For this reason, in the first conventional projector, an optical shutter is arranged on the light source side of the liquid crystal display panel, and light is intermittently blocked by the optical shutter, so that the tailing phenomenon (so-called motion blur) is alleviated. Thus, a high-quality moving image display is obtained (see Patent Document 1).

  Further, in the second conventional projector, a rotating prism for scanning illumination light is arranged on the light source side of the liquid crystal display panel, and the illumination light is scanned in the image forming area by the rotating prism (Patent Document). 2).

In the third conventional projector, the liquid crystal display panel itself displays black for each line of the scanning line electrodes and performs interlaced display for switching the black line between the previous image and the next image. (See Patent Document 3).
JP 2002-148712 A JP 2004-139020 A JP 2002-132220 A

  However, in the first conventional projector, since the light shirter is arranged immediately before the liquid crystal display panel, the degree of freedom of the shape of the light shirter is limited, and the possibility of adverse effects such as vibration on the liquid crystal display panel is also increased. To do.

  Also in the second conventional projector, a motor for rotating the rotating prism is indispensable, and the sound of the motor itself and the vibration sound due to resonance with the motor may become an unpleasant noise. Furthermore, in such a projector, the angle of the rotating prism and the moving speed of the strip-shaped illumination light are non-linear, resulting in uneven illuminance in the screen, and there is a difference in the effect of improving the tailing phenomenon in the screen. Occurs.

  In the third conventional projector, since black is displayed on the lines adjacent to both sides of the display line of the liquid crystal display panel, the luminance peak tends to be small and the contrast tends to decrease.

  Therefore, an object of the present invention is to provide a projector that can insert a light shielding means for intermittently irradiating illumination light with few restrictions, can reduce noise, and can display a high contrast.

  In order to solve the above problems, a projector according to the present invention includes: (a) a light source device that emits light source light; (b) a first lens array that divides light source light from the light source device into a plurality of partial light beams; A homogenizing optical system having a second lens array and a superimposing optical element that forms and superimposes the partial light flux divided by the first lens array on the illumination area; and (c) at a position where the partial light flux is superimposed by the superimposing optical element. A light shielding type light modulating means that is disposed and spatially blocks illumination light emitted from the homogenizing optical system; and (d) a relay optical system disposed at a subsequent stage of the light shielding type light modulating means; and (e). An optical modulation unit that is arranged at a substantially conjugate position with respect to the light-shielding light modulation means via the relay optical system, and modulates the illumination light in accordance with image information, and (f) modulated by the light modulation unit Project modulated light as image light And a projection optical system for.

  In the projector, the light-shielding light modulation means is arranged at the position where the partial light beam is superimposed by the superimposing optical element, and is uniformly illuminated by the light source light that has passed through the uniformizing optical system. Further, in this projector, the light modulating unit is disposed at a position substantially conjugate with the light shielding type light modulating unit via the relay optical system, so that interference between the light modulating unit and the light shielding type light modulating unit is avoided. On the other hand, it is possible to accurately project the transmission pattern image of the light-shielding light modulation means onto the light modulation unit. Therefore, accurate intermittent illumination is possible using the transmission pattern image formed on the light-shielding light modulation means that is easy to incorporate and does not generate vibration, and a high-contrast image with reduced moving image blur can be projected.

  Further, according to a specific aspect or aspect of the present invention, the light-shielding type light modulating means performs intermittent light shielding in units of scan electrode lines or pixels. In this case, an image with less flicker can be projected by a high-definition transmission pattern image in which a light-shielding portion is formed in units of lines or pixels.

  According to another aspect of the present invention, the homogenizing optical system further includes a polarization conversion element that aligns the polarization direction of the partial light beams in a predetermined direction, and the light modulation unit includes a liquid crystal display panel. In this case, the liquid crystal display panel provided in the light modulation unit can be efficiently illuminated by the polarized light.

  According to another aspect of the present invention, the light-shielding type light modulation means includes a liquid crystal display panel or a tilt mirror device. In this case, it is easy to modulate the spatial distribution of the illumination light with high definition.

  According to another aspect of the present invention, the light-shielding light modulation means is disposed so as to be retractable on the optical path of the illumination light. In this case, by retracting the light-shielding light modulation means from the optical path, the light modulation unit can be illuminated with higher illuminance, and projection in a mode that prioritizes brightness is possible.

  In addition, according to another aspect of the present invention, a color separation optical system and a color synthesis optical system are further provided. The color separation optical system has at least one color separation dichroic mirror disposed at an inclination with respect to the illumination optical axis in the subsequent stage of the homogenization optical system, and the illumination light emitted from the homogenization optical system A plurality of color lights are separated from each other, and the plurality of color lights are respectively guided to the optical paths of the respective colors, and a relay lens disposed in at least one of the optical paths of the respective colors is included as a relay optical system. The magnification from the light modulation means to the light modulation unit is made the same. The light modulators are respectively arranged on the optical paths of the respective colors and are incident in a state where the transmitted images of the light-shielding light modulators coincide with each other, and a plurality of color lights corresponding to the transmitted images are respectively provided according to image information. A light modulation device for each color to be modulated is included. The color synthesis optical system synthesizes the image light of each color from the light modulation device of each color and emits it to the projection optical system. In this case, intermittent illumination can be performed collectively for each light modulation device by a transmission image formed on a single light-shielding light modulation means, and efficient illumination by a simple illumination system is possible. Become. Thereby, it is possible to project a color image easily and with high accuracy.

  Further, according to another aspect of the present invention, the color separation optical system incorporates an equal optical path relay optical system or a double relay optical system as a relay optical system, so that the light modulation unit is changed from the light-shielding light modulation unit for each color. The magnification is the same. Here, the equal optical path relay optical system means that the length of the optical path of each color is substantially equivalent by using a relay lens that is common or equivalent in the optical path of each color, and the projection magnification of the illumination light of each color is equal. Means what to do. In addition, the double relay optical system is a method for specifying in a light modulation device by interposing a lens that forms an image twice in a light path of a specific color when the light path of a specific color is longer than the light path of another color. This means that the projection magnification of the specific color is made equal to the projection magnification of the other color while avoiding the inversion of the projection image of the illumination light of the color. In this case, it is possible to project the transmission pattern image formed on the light-shielding type light modulation means so as to easily match the light modulation device of each color, and to project a high-quality color image with less moving image blur.

  Hereinafter, a projector according to an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram conceptually illustrating the optical system of the projector 1 according to the first embodiment of the present invention. The projector 1 is an optical device that modulates a light beam emitted from a light source according to image information to form an optical image and projects it on a screen in an enlarged manner. The light source lamp unit 10, a uniformizing optical system 20, a light shield The optical element which comprises the apparatus 30, the color separation optical system 40, the optical apparatus 50, and the projection optical system 60, and comprises the light source lamp unit 10, various optical systems 20, 30, 40, 50, etc. is predetermined. The optical axis housing IX is positioned and adjusted and accommodated in an optical component casing (not shown) in which the system optical axis IX is set.
The projector 1 includes a plurality of fans (not shown), and a cooling mechanism for the light source lamp unit 10, the optical systems 20, 30, 40, 50, and the like is configured by these fans.

The light source lamp unit 10 is a light source device that collects and emits light from the light source and illuminates the optical device 50 through the optical systems 20, 30, 40, and the like. The light source lamp unit 10 includes a light source lamp 11 that is an arc tube and an elliptical reflector. A main reflecting mirror 12, a sub-reflecting mirror 14 that is a spherical reflector, and a collimating concave lens 15 are provided. The main reflecting mirror 12 can also be a parabolic reflector, and in this case, the collimating concave lens 15 is not necessary.
In this light source lamp unit 10, the light flux emitted from the light source lamp 11 to the surroundings is collected by the main reflecting mirror 12 and the sub-reflecting mirror 14, collimated by the collimating concave lens 15, and emitted to the uniformizing optical system 20 side. The

  The homogenizing optical system 20 is mainly for homogenizing the in-plane illuminance of the target illumination area, and includes a first lens array 21, a second lens array 22, a PBS array 23, a condenser lens 24, and a field. A lens 26 is provided. The homogenizing optical system 20 divides the light beam emitted from the light source lamp unit 10 into a plurality of partial light beams, and superimposes the plurality of light beams on a light-shielding image forming region provided at a position of a light-shielding device 30 described later. Make it incident.

  The first lens array 21 has a function as a light beam splitting optical element that splits the light beam emitted from the light source lamp 11 into a plurality of partial light beams, and is arranged in a matrix in a plane orthogonal to the system optical axis IX. A plurality of small lenses are provided, and the contour shape of each small lens is a light-shielded image forming region of the liquid crystal display panel 31 of the light-shielding device 30 described later and the liquid crystal display panels 51b, 51g, and 51r constituting the optical device 50. It is set so as to be almost similar to the shape of the image forming area.

  The second lens array 22 is an optical element that forms an image on the illumination area with a plurality of partial light beams divided by the first lens array 21 described above, and is a surface orthogonal to the system optical axis IX, similar to the first lens array 21. A plurality of small lenses are arranged in a matrix.

The PBS array 23 is a polarization conversion element that aligns the polarization direction of each partial light beam divided by the first lens array 21 with linear polarization in one direction.
Although not shown in detail, the PBS array 23 has a configuration in which polarization separation films and reflection mirrors that are inclined with respect to the system optical axis IX are alternately arranged. The former polarization separation film transmits one polarized light beam among the P-polarized light beam and S-polarized light beam included in each partial light beam, and reflects the other polarized light beam. The other polarized light beam reflected is bent by the latter reflecting mirror and emitted in the emission direction of the one polarized light beam, that is, the direction along the system optical axis IX. Either of the emitted polarized light beams is polarized and converted by a phase difference plate provided in a stripe shape on the light beam exit surface of the PBS array 23, and the polarization directions of all the polarized light beams are aligned. By using such a PBS array 23, the light beam emitted from the light source lamp 11 can be aligned with the polarized light beam in one direction, so that the utilization factor of the light source light used in the optical device 50 can be improved. .

The condenser lens 24 is a superimposing optical element that condenses a plurality of partial light beams that have passed through the first lens array 21, the second lens array 22, and the PBS array 23 and superimposes them on the illumination area of the light shielding device 30.
The light beam emitted from the condenser lens 24 is incident on the light shielding image forming region provided in the light shielding device 30 at the next stage in a uniform state.

  The field lens 26 converts each partial light beam incident on the light shielding image forming region of the light shielding device 30 by the condenser lens 24 into a light beam parallel to the principal ray of each partial light beam, and enters the light shielding device 30. It has a function of narrowing the angle distribution width of the incident angle of the light beam and improving the modulation accuracy of the light shielding device 30 (liquid crystal display panel 31).

The light-shielding device 30 is a light-shielding light modulator that modulates an incident light beam according to light-shielding information to form a transmission pattern image, and includes a liquid crystal display panel 31. An incident side polarizing plate 32 is disposed on the incident side of the liquid crystal display panel 31, and an exit side polarizing plate 33 is disposed on the exit side of the liquid crystal display panel 31. Here, the liquid crystal display panel 31 and the pair of polarizing plates 32 and 33 sandwiching the liquid crystal display panel 31 constitute a liquid crystal light valve for two-dimensionally modulating the illumination light. Of these, both the incident side polarizing plate 32 and the emission side polarizing plate 33 can be omitted.
In each color liquid crystal light valve, a detailed description is omitted between the liquid crystal display panel 31 and the exit-side polarizing plate 33, but a WV (wide view) film may be disposed.

The liquid crystal display panel 31 is formed by sealing a liquid crystal, which is an electro-optical material, in a pair of transparent glass substrates. For example, a polysilicon TFT is used as a switching element to each pixel according to a given ON / OFF signal. Modulates the polarization direction of the incident polarized light beam. Specifically, for example, when an applied voltage to a specific pixel of a normally-on (normally white) liquid crystal display panel 31 is turned on, the polarization direction of illumination light passing through the incident-side polarizing plate 32 is rotated by 90 °. The black display is absorbed by the emission side polarizing plate 33. When the voltage is not applied to the specific pixel of the liquid crystal display panel 31 and is OFF, the polarization direction of the illumination light that has passed through the incident-side polarizing plate 32 passes through the emission-side polarizing plate 33 as it is to display white. The light-shielding image forming area for modulating the liquid crystal display panel 31 is rectangular, and its diagonal dimension is, for example, 0.7 inches.
The liquid crystal display panel 31 is disposed at a position substantially conjugate with the first lens array 21 provided in the homogenizing optical system 20 and at a substantially focal position of the condenser lens 24. A rectangular light-shielding image forming area having an outline corresponding to the outline of the small lens is illuminated uniformly. That is, the partial light beams divided by the first lens array 21 are superimposed at the position of the liquid crystal display panel 31, and the illumination light is made uniform at this position (that is, the light-shielding image forming region). .

  The illumination light incident on the liquid crystal display panel 31 is alternately modulated in units of scanning electrode lines (hereinafter referred to as scanning lines) or in units of pixels. That is, in cooperation with the polarizing plates 32 and 33, for example, a stripe-shaped transmission pattern image or a checkered transmission pattern image can be formed, and such a transmission pattern image is inverted. By alternately switching with the transmission pattern image, the liquid crystal display panels 51b, 51g, 51r constituting the optical device 50 can be intermittently illuminated on a pixel basis.

The light shielding device 30 can be displaced or moved as a whole by a movable mechanism (not shown). In other words, the liquid crystal light valve including the liquid crystal display panel 31 and the polarizing plates 32 and 33 can be retracted from the system optical axis IX, and is again disposed on the system optical axis IX as necessary. Can be done. The liquid crystal light valve such as the liquid crystal display panel 31 can be finely moved two-dimensionally in the direction perpendicular to the system optical axis IX by the above-described movable mechanism, and the liquid crystal display panels 51b and 51g constituting the optical device 50 are provided. , 51r can be precisely aligned.
When the liquid crystal light valve composed of the liquid crystal display panel 31 or the like is retracted from the system optical axis IX, the glass plate 35 is disposed on the system optical axis IX to compensate for the optical path length. As described above, when the liquid crystal light valve is retracted from the system optical axis IX, the light flux from the light source lamp unit 10 can be supplied to the optical device 50 nearly 100%. Image projection is possible. However, in this case, the effect of preventing moving image blur by intermittent illumination using spatial blocking of illumination light cannot be obtained.

  The color separation optical system 40 includes first and second dichroic mirrors 41a and 41b, reflection mirrors 42a, 42b, 42c, 42d, and 42e, field lenses 43b, 43g, and 43r, an incident lens 44, a relay lens 45a, 45b. The color separation optical system 40 includes first and second dichroic mirrors 41a and 41b as basic elements, and separates the illumination light into three light beams of red light, green light, and blue light. That is, the first dichroic mirror 41a provided on the incident side reflects the blue light LB among the three colors of red, blue, and green (R, G, and B) and transmits the green light LG and the red light LR. The second dichroic mirror 41b is disposed on the optical path of the transmitted lights LG and LR of the first dichroic mirror 41a, reflects the green light LG of the two color lights LG and LR, and transmits the red light LR.

  In the color separation optical system 40, the uniformed illumination light emitted from the light shielding device 30 enters the first dichroic mirror 41a via the incident lens 44. The blue light LB reflected by the first dichroic mirror 41a is guided to the first optical path OP1, and is supplied to the optical device 50 via the reflection mirror 42a, the relay lens 45a, and the reflection mirrors 42b and 42c via the field lens 43b. The Of the color lights LG and LR transmitted through the first dichroic mirror 41a and passing through the reflection mirror 42d and the relay lens 45b, the green light LG reflected by the second dichroic mirror 41b is guided to the second optical path OP2 and reflected. The light is supplied to the optical device 50 through the mirror 42a and the field lens 43g. Further, the red light LR that has passed through the second dichroic mirror 41b is guided to the third optical path OP3, and is supplied to the optical device 50 via the reflection mirror 42e and the field lens 43r.

  Here, the relay lenses 45 a and 45 b are equal optical path relay optical systems that transmit the illumination light captured by the incident lens 44 to the field lenses 43 b, 43 g, and 43 r on the emission side, and the liquid crystal display panel 31 by the uniformizing optical system 20. The image of the light-shielding image forming area formed at the position is formed on the image forming areas provided on the respective liquid crystal display panels 51b, 51g, 51r constituting the optical device 50. In other words, the image of the light-shielded image forming area of the liquid crystal display panel 31 is transmitted through the relay lenses 45a and 45b to the respective color lights by aligning the left and right and up and down directions on the image forming areas of the liquid crystal display panels 51b, 51g, and 51r. At the same magnification. The first relay lens 45a is dedicated to the blue light LB, and the second relay lens 45b is used for both the green light LG and the red light LR. The shapes of the optical surfaces of the relay lenses 45a and 45b are merely examples, and can be appropriately changed including the refractive power.

  In the color separation optical system 40, field lenses 43 b, 43 g, 43 r provided in the preceding stage of the optical path of each color light of the optical device 50 are emitted from the second lens array 22 of the homogenizing optical system 20 and pass through the liquid crystal display panel 31. Each partial light beam thus passed is converted into a light beam parallel to the principal ray of each partial light beam, the angle distribution width of the incident angle of the light beam incident on each liquid crystal display panel 51b, 51g, 51r is narrowed, and each liquid crystal display panel 51b. , 51g, 51r have a function of improving the modulation accuracy.

The optical device 50 is a light modulation unit that modulates an incident light beam according to image information to form a color image, and includes liquid crystal display panels 51b, 51g, and 51r as light modulation devices to be illuminated, and color synthesis optics. And a cross dichroic prism 54 as a system. Incident-side polarizing plates 52b, 52g, and 52r are interposed between the field lenses 43b, 43g, and 43r and the liquid crystal display panels 51b, 51g, and 51r, and the liquid crystal display panels 51b, 51g, and 51r and the cross dichroic prism 54 are interposed. In between, the exit side polarizing plates 52b, 52g, and 52r are interposed. Here, for example, the liquid crystal display panel 51b for blue light LB and the pair of polarizing plates 52b and 52b sandwiching the liquid crystal display panel 51b constitute a liquid crystal light valve for two-dimensionally modulating the luminance of illumination light. Similarly, the liquid crystal display panel 51g for green light LG and the corresponding polarizing plates 52g and 52g also constitute a liquid crystal light valve, and the liquid crystal display panel 51r for red light LR and the corresponding polarizing plates 52r and 52r are also A liquid crystal light valve is constructed.
In each color liquid crystal light valve, a WV (wide view) film is disposed between the liquid crystal display panels 51b, 51g, and 51r and the exit-side polarizing plates 52b, 52g, and 52r, although detailed description is omitted. You can also.

  Each of the liquid crystal display panels 51b, 51g, 51r is similar to the liquid crystal display panel 31 of the light shielding device 30, in which a liquid crystal as an electro-optical material is hermetically sealed in a pair of transparent glass substrates. As a switching element, the polarization direction of the polarized light beam incident on each pixel is modulated in accordance with a given image signal. In the liquid crystal display panels 51b, 51g, 51r, the image forming area to be modulated is a rectangle similar to or congruent with the light-shielding image forming area of the liquid crystal display panel 31.

  FIG. 2 is a diagram for explaining the projection of the liquid crystal display panel 31 onto the liquid crystal display panels 51b, 51g, and 51r. On the image forming area FA provided in each liquid crystal display panel 51b, 51g, 51r, an inverted image of the transmission pattern image formed in the image forming area provided in the liquid crystal display panel 31, that is, the light shielding image forming area FA is projected. In this case, the inverted transmission pattern image of the same magnification is projected due to the presence of the relay lenses 45a, 45b, etc., but when the sizes of the liquid crystal display panel 31 and the liquid crystal display panels 51b, 51g, 51r are different, there is a difference in size. The projection magnification can be changed according to the ratio, and the 1: 1 projection with the magnification changed between the light-shielding image forming area FA of the liquid crystal display panel 31 and the image forming areas FA of the liquid crystal display panels 51b, 51g, 51r. Is possible.

  For example, the image area IP1 formed in the center of the liquid crystal display panel 31 is projected onto the image area IP2 formed in the center of each liquid crystal display panel 51b, 51g, 51r. Here, in the image region IP1 of the liquid crystal display panel 31, a light-shielding portion BL that is an aggregate of light-shielding pixels and a light-transmitting portion WL that is an aggregate of transmissive pixels are formed in stripes in units of scanning electrode lines. The first transmission pattern image PA1 can be formed, or the second transmission pattern image PA2 in which the light and dark patterns of the first transmission pattern image PA1 are replaced can be formed. Correspondingly, on the image area IP2 of each liquid crystal display panel 51b, 51g, 51r, the first transmission pattern image PA1 spatially reversed at the time of transfer or the second spatially reversed at the time of transfer. The transmission pattern image PA2 is projected. Such transmissive pattern images PA1, PA2 are alternately and repeatedly projected at appropriate timings corresponding to the frames displayed on the respective liquid crystal display panels 51b, 51g, 51r, whereby the respective liquid crystal display panels 51b, 51g, 51r are projected. Can be intermittently illuminated, and the effect of preventing motion blur can be obtained.

  FIG. 3 is a diagram for explaining a modification of intermittent illumination for the liquid crystal display panels 51b, 51g, and 51r. FIG. 3A shows a checkered first transmission pattern image PA1 ′ formed in the image area IP1 of the liquid crystal display panel 31 and projected onto the image area IP2 of the liquid crystal display panels 51b, 51g, 51r. 3 (b) shows an inverted second transmission pattern image PA2 ′ similarly projected onto the image area IP2 of the liquid crystal display panels 51b, 51g, 51r. By projecting these transmissive pattern images PA1 ′ and PA2 ′ alternately and at appropriate timing, the liquid crystal display panels 51b, 51g, and 51r can be intermittently illuminated, and an effect of preventing motion blur can be obtained. It is done.

  In the illustrated transmission pattern images PA1, PA2, PA1 ′, and PA2 ′, the light shielding portions are periodically formed in units of lines or pixels. However, the periodic light shielding portions are formed in units of multiple lines or pixels. It can also be formed. However, the smaller the width and size of the light-shielding portion, the more advantageous is the flicker reduction.

  FIG. 4A is a diagram for explaining the illumination state of specific lines and pixels of the liquid crystal display panels 51b, 51g, and 51r. FIG. 4B is a diagram for explaining the rewrite timing of each of the liquid crystal display panels 51b, 51g, 51r. In a state where the specific lines and pixels are shaded by the transmissive pattern images PA1 and PA2 and are in a dark state, the next liquid crystal display panels 51b, 51g, and 51r corresponding to the gaps of the currently illuminated half-frame images The image information is rewritten for the half frame image. The operation described above is merely an example, and the rewriting timing of each of the liquid crystal display panels 51b, 51g, and 51r can be changed as appropriate according to the application and the characteristics of the liquid crystal display panels 51b, 51g, and 51r. Further, it is desirable that the rewriting time of the liquid crystal display panels 51b, 51g, 51r is shorter than the time of the dark state by the light shielding device 30.

  Returning to FIG. 1, the cross dichroic prism 54 is an optical element that forms a color image by synthesizing an optical image modulated for each color light emitted from the emission-side polarizing plate. The cross dichroic prism 54 has a substantially square shape in plan view in which four right angle prisms are bonded together, and a pair of dielectric multilayer films 54a and 54b intersecting in an X shape are formed at the interface where the right angle prisms are bonded to each other. Is formed. The dielectric multilayer films 54a and 54b are dichroic mirrors that reflect a light beam in a predetermined wavelength region and transmit a light beam in another wavelength region. One dielectric multilayer film 54a reflects blue light as a first composite dichroic mirror, and the other dielectric multilayer film 54b reflects red light as a second composite dichroic mirror. By these dielectric multilayer films 54a and 54b, the red light and the blue light are bent and aligned with the traveling direction of the green light, so that the three color lights are synthesized.

  The combined light emitted from the cross dichroic prism 54 is enlarged and projected by the projection optical system 60 to form a large screen color image on a screen (not shown).

FIG. 5 is a block diagram conceptually illustrating a part of the signal processing circuit built in the projector 1 of FIG.
The signal processing circuit includes an image data processing unit 71 to which an external video signal such as a video signal is input, a panel driving unit 73 for driving the liquid crystal display panels 31, 51b, 51g, and 51r shown in FIG. And a control unit 75 that comprehensively controls the operation.

  Among the above, the image data processing unit 71 can correct the size and distortion or correct the color balance by performing appropriate processing on the video signal input from the outside. The image data processing unit 71 enables interlaced display by determining data to be assigned to each pixel of the liquid crystal display panels 51b, 51g, and 51r. That is, data for forming an image that is thinned out every other line, for example, in the image area IP2 of the liquid crystal display panels 51b, 51g, 51r is prepared. Further, the image data processing unit 71 prepares data corresponding to the transmission pattern images PA1 and PA2 to be formed in the image area IP1 of the liquid crystal display panel 31.

  The panel drive unit 73 adjusts the operation state of the liquid crystal display panels 51b, 51g, and 51r for each color and the liquid crystal display panel 31 for intermittent illumination based on the processed video signal output from the image data processing unit 71. Generate a signal. Thereby, in the liquid crystal light valve composed of the liquid crystal display panels 51b, 51g, 51r and the polarizing plates 52b, 52g, 52r associated therewith, the transmittance distribution corresponding to the video signal or the like input from the image data processing unit 71. Desired image can be formed. Further, in the liquid crystal light valve composed of the liquid crystal display panel 31 and the accompanying polarizing plates 32 and 33, a pair of transmission pattern images PA1 and PA2 for intermittently illuminating the liquid crystal display panels 51b, 51g and 51r are sequentially switched and formed. can do.

The control unit 75 is for controlling the operation of the image data processing unit 71 and the like, and adjusts the image to be displayed on the liquid crystal display panel 31 and the liquid crystal display panels 51b, 51g, 51r. As a result, intermittent illumination using spatial blocking of illumination light by the liquid crystal display panel 31 is possible, and pulse display is possible when displaying moving images by the liquid crystal display panels 51b, 51g, 51r, thereby preventing moving image blurring. Can do.
The control unit 75 sets the non-moving image mode when the projector 1 displays a still image or the like. In this case, a mechanism (not shown) is driven to retract the liquid crystal light valve including the liquid crystal display panel 31 from the system optical axis IX, and the glass plate 35 is disposed on the system optical axis IX. In addition, the liquid crystal display panels 51b, 51g, and 51r perform a high-luminance display operation corresponding to permanent illumination.
As described above, instead of retracting the liquid crystal light valve composed of the liquid crystal display panel 31 and the like from the system optical axis IX, the liquid crystal display panel 31 is of a normally ON (white) type, and all the pixels of the liquid crystal display panel 31 are arranged. By turning off the drive voltage, the liquid crystal display panel 31 can also be in a fully transmissive state. Also in this case, the liquid crystal display panels 51b, 51g, 51r can perform a display operation with high luminance.

  In the above description, the transmission pattern images PA1, PA2, PA1 ′, and PA2 ′ including the light shielding portion BL and the light transmitting portion WL are formed in the image area IP1 of the liquid crystal display panel 31, but the light transmitting portion WL is formed. Can be a transmission pixel whose luminance is modulated in accordance with the image to be displayed on the liquid crystal display panels 51b, 51g, 51r. That is, the pixel corresponding to the light transmitting portion WL of the liquid crystal display panel 31 is projected by the projector 1 by modulating the transmittance with a luminance signal or the like among the video signals to be displayed on the liquid crystal display panels 51b, 51g, 51r. The black of the image can be further enhanced, and an image with increased contrast can be projected.

[Second Embodiment]
FIG. 6 is a diagram for conceptually explaining the optical system of the projector 101 according to the second embodiment. The projector 101 according to the second embodiment is a modification of the projector according to the first embodiment, and common portions are denoted by the same reference numerals and redundant description is omitted. In addition, regarding parts not specifically described, it is assumed that the projector 101 of the second embodiment has the same structure as the projector of the first embodiment.

In the projector 101, the color separation optical system 140 includes first and second dichroic mirrors 41a and 41b, reflection mirrors 142a, 142b, and 142c, field lenses 43b, 43g, and 43r, an incident lens 44, and a relay lens 145a. , 145b, 145c.
In the color separation optical system 140, the uniformed illumination light emitted from the light shielding device 30 enters the first dichroic mirror 41a via the incident lens 44 and the relay lens 145a. The blue light LB reflected by the first dichroic mirror 41a is guided to the first optical path OP1, and after being reflected by the reflection mirror 142a, is supplied to the optical device 50 via the field lens 43b. Of the color lights LG and LR transmitted through the first dichroic mirror 41a, the green light LG reflected by the second dichroic mirror 41b is guided to the second optical path OP2 and supplied to the optical device 50 via the field lens 43g. Is done. Further, the red light LR transmitted through the second dichroic mirror 41b is guided to the third optical path OP3, passes through the reflection mirrors 142b and 142c and the relay lenses 145b and 145c, and is then supplied to the optical device 50 through the field lens 43r. The

Here, the relay lens 145a transmits the illumination light captured by the incident lens 44 to the field lenses 43b, 43g, etc. on the exit side, and the uniformizing optical system 20 uses the light shielding image forming area FA of the liquid crystal display panel 31. The transmission pattern images PA1 and PA2 formed at the positions have a role of forming an image on the image forming area FA such as the liquid crystal display panels 51b and 51g constituting the optical device 50. The relay lens 145a is used for both the blue light LB and the green light LG.
Further, the relay lenses 145b and 145c connect the transmission pattern images PA1 and PA2 once formed on the third optical path OP3 by the relay lens 145a to the image forming area FA of the red liquid crystal display panel 51r constituting the optical device 50. Image. These relay lenses 145b and 145c constitute a double relay optical system, and can form an equal-magnification erect image by image formation twice. As a result, even if the length of the optical path of the red light LR is longer than the length of the optical path of the blue light LB and the length of the optical path of the green light LG, the transmission pattern images PA1, PA2 of the light shielding image forming area FA of the liquid crystal display panel 31. Are projected at the same magnification on each color light with the left and right and the top and bottom aligned on the image forming area FA of each liquid crystal display panel 51b, 51g, 51r.

[Third Embodiment]
FIG. 7 is a diagram for conceptually explaining the optical system of the projector 201 according to the third embodiment. The projector 101 according to the third embodiment is a modification of the projector according to the first embodiment, and parts that are not particularly described have the same structure as the projector according to the first embodiment.

  In the projector 201, the light shielding device 230 is a light shielding type light modulation unit that replaces the liquid crystal display panel 31 or the like of FIG. 1 and includes a tilt mirror device 231. The tilt mirror device 231 modulates the incident light beam according to the light shielding information to form transmission pattern images PA1, PA2, PA1 ', PA2' as exemplified in FIG.

  Although the present invention has been described with reference to the embodiment, the present invention is not limited to this. For example, in the above-described embodiment, the PBS array 23 in which the light from the light source lamp unit 10 or the like is polarized in a specific direction is used. However, the present invention is also applicable to a projector that does not use such a PBS array 23. .

  In the above embodiment, the illumination light is divided using the color separation optical system 40, the image light of each color is formed by the liquid crystal display panels 51b, 51g, and 51r, and the composite image is obtained by the cross dichroic prism 54. However, the color separation optical system 40 and the cross dichroic prism 54 may be omitted, and the liquid crystal display panels 51b, 51g, and 51r may be single-plate monochrome or color display panels.

  Further, as the projector, there are a front projector that projects an image from the direction of observing the projection surface and a rear projector that projects an image from the side opposite to the direction of observing the projection surface. The projector 1 shown in FIG. , 101, 201 can be applied to any of them.

It is a figure explaining the optical system of the projector which concerns on 1st Embodiment. It is a figure explaining formation and projection of the transmission pattern image in the projector of FIG. (A), (b) is a figure explaining the modification of a transmissive pattern image. (A), (b) demonstrates the operation timing etc. of a liquid crystal display panel. It is a block diagram explaining the circuit built in the projector of FIG. It is a figure explaining the optical system of the projector which concerns on 2nd Embodiment. It is a figure explaining the optical system of the projector which concerns on 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Projector, 10 ... Light source lamp unit, 20 ... Uniformization optical system, 21 ... 1st lens array, 22 ... 2nd lens array, 24 ... Condenser lens, 26 ... Field lens, 30 ... Light-shielding device, 31 ... Liquid crystal display Panel 32. Incident side polarizing plate 33. Emission side polarizing plate 35 35 Glass plate 40 Color separation optical system 41 a First dichroic mirror 41 b Second dichroic mirror 45 a 45 b Relay lens 50 Optical device 51b, 51g, 51r Liquid crystal display panel 54 Cross dichroic prism 60 Projection optical system 71 Image data processing unit 73 Panel drive unit 75 Control unit BL Light blocking unit WL ... translucent part, FA ... image forming area, shading image forming area, OP1 ... first optical path, OP2 ... second optical path, OP3 ... Third optical path, PA1, PA2 ... Transmission pattern image

Claims (7)

A light source device that emits light source light;
A first lens array that divides light source light from the light source device into a plurality of partial light beams, a second lens array that superimposes the partial light beams divided by the first lens array by forming an image on an illumination area, and a superimposing optical element A homogenizing optical system having
A light-blocking light modulation means that is disposed at a position where the partial light beam is superimposed by the superimposing optical element and spatially blocks illumination light emitted from the homogenizing optical system;
A relay optical system disposed at a subsequent stage of the light-shielding light modulation means;
A light modulation unit that is arranged at a position substantially conjugate to the light-shielding light modulation unit via the relay optical system, and modulates illumination light according to image information;
A projection optical system that projects the modulated light modulated by the light modulator as image light;
A projector comprising:   2. The projector according to claim 1, wherein the light-shielding light modulator performs intermittent light shielding in units of scanning electrode lines or pixels.   3. The homogenization optical system further includes a polarization conversion element that aligns the polarization direction of the partial light flux in a predetermined direction, and the light modulation unit includes a liquid crystal display panel. A projector according to claim 1.   4. The projector according to claim 1, wherein the light-shielding light modulation unit includes a liquid crystal display panel or a tilt mirror device. 5.   The projector according to any one of claims 1 to 4, wherein the light-shielding light modulation means is disposed so as to be retractable on an optical path of illumination light. In the subsequent stage of the homogenizing optical system, the optical system has at least one color separation dichroic mirror disposed to be inclined with respect to the illumination optical axis, and separates a plurality of color lights from the illumination light emitted from the homogenizing optical system. Then, the plurality of color lights are respectively guided to the optical paths of the respective colors, and a relay lens disposed in at least one of the optical paths of the respective colors is included as the relay optical system, and the light-shielding light modulation unit for the respective colors A color separation optical system that makes the magnification to the light modulation unit the same;
The light modulators are respectively arranged on the optical paths of the respective colors and are incident with the transmitted images of the light-shielding light modulators being coincident with each other, and the plurality of color lights corresponding to the transmitted images according to image information Each color modulating device that modulates each,
6. The projector according to claim 1, further comprising a color synthesis optical system that synthesizes the image light of each color from the light modulation device of each color and emits the light to the projection optical system. . In the color separation optical system, an equal optical path relay optical system or a double relay optical system is incorporated as the relay optical system so that magnifications of the respective colors from the light-shielding light modulation means to the light modulation unit are made the same. The projector according to claim 6.

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