JP2006220755A - Image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a change of the color temperature of illuminating light due to an adjustment of contrast and brightness, regarding an image display apparatus capable of selecting either one of cases giving priority to the contrast of a displayed image or giving priority to the brightness in accordance with ambient brightness. <P>SOLUTION: The apparatus includes an illuminating optical system on which the illuminating light emitted from a white light source 11 is made incident, a color separating means 23 for separating the illuminating light coming from the illuminating optical system into three primary colors and making the light incident on spatial light modulation elements 24R, 24G, 24B, a color synthesizing means 23 for synthesizing the modulated light modulated by the spatial light modulating elements 24R, 24G and 24B, an imaging optical system 26 for imaging the modulated light coming from the color synthesizing means 23, a variable aperture diaphragm 17 for partly shielding the illuminating light, and a filter 18 for partly decaying the optional wavelength band components of the illuminating light. Regarding the illuminating light passing through the variable aperture diaphragm 17, a light quantity ratio of the illuminating light made incident on the filter 18 to the illuminating light not made incident on the filter 18 is always kept constant, irrespective of the stop degree of the variable aperture diaphragm 17. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image display device that displays an image displayed by a spatial light modulation element via an imaging optical system such as a projection lens.

  Conventionally, illumination light for a spatial light modulation element such as a liquid crystal light valve is modulated by this spatial light modulation element, and this modulated light is enlarged and imaged on a screen via an imaging optical system such as a projection lens, An image display device for displaying an image has been proposed. In such an image display device, the light quantity and the polarization state of the illumination light are controlled by controlling the illumination light for each pixel of the spatial light modulation element using a reflective or transmissive spatial light modulation element. The modulation is done.

  FIG. 4 is a side view showing a schematic configuration of a so-called “lens array type” conventional image display apparatus.

  In this image display device, as shown in FIG. 4, illumination light emitted from a light source 101 is irradiated onto the spatial light modulation element 103 via the illumination optical system 102 to illuminate the spatial light modulation element 103. I am doing so. This image display device is a “lens array type” image display device, and uses an illumination optical system 102 that superimposes and illuminates the spatial light modulation element 103 with a lens array.

  In this image display device, as shown in FIG. 4, the illumination light emitted from the light source 101 is reflected by the reflector 104 and emitted in the optical axis direction. The illumination optical system 102 includes a first lens array (fly eye lens) 105, a second lens array (fly eye lens) 106, an overlapping lens 107, and a condenser lens 108. On the first and second lens arrays 105 and 106, a plurality of lens cells having openings substantially similar to the spatial light modulation element 103 are two-dimensionally arranged, and the exit opening surface of the reflector 104 is spatially arranged. It is divided.

  Each lens cell of the first lens array 105 condenses the light flux on the lens cell of the second lens array 106 corresponding to each lens cell. The same number of secondary light source images as the lens cells of the first lens array 105 are formed on the second lens array 106. On the other hand, each lens cell on the second lens array 106 makes the image of each lens cell opening of the corresponding first lens array 105 coincide with the incident surface of the spatial light modulator 103, and the overlapping lens 107, condenser Through the lens 108 and the polarization beam splitter 109, the images of the lens cells of the first lens array 105 are overlapped on the incident surface of the spatial light modulator 103.

  In this way, a plurality of secondary light source images are formed in the second lens array 106. Further, a plurality of tertiary light source images are formed in the overlapping lens 107. The condenser lens 108 is arranged so that the illumination light of the spatial light modulator 103 is incident in the direction of the entrance pupil of a projection lens (not shown).

  As a result, the intensity of the illumination light reflected by the reflector 104 is integrated, and the spatial light modulator 103 is superimposed and illuminated with a uniform intensity distribution by the plurality of secondary or tertiary light source images. In this way, the first and second lens arrays 105 and 106 and the overlapping lens 107 constitute the illumination optical system 102.

  The spatial light modulation element 103 includes, for example, a transmissive or reflective liquid crystal plate in which a plurality of liquid crystal cells are two-dimensionally arranged, and an analyzer (polarizing plate) that transmits only polarized light in a predetermined direction. Then, the liquid crystal plate is controlled by an electric signal, so that the transmitted or reflected light is polarized and modulated. That is, the illumination light is modulated into P-polarized light and S-polarized light according to image information in the spatial light modulation element 103.

  Note that a light beam whose incident angle is shifted in a direction orthogonal to a plane including the incident optical axis and the outgoing optical axis with respect to the polarizing beam splitter 109 has a polarization direction after passing through the polarizing beam splitter 109 as a liquid crystal light valve. 109 will deviate from the optimal direction. Therefore, by arranging a λ / 4 plate (quarter wavelength plate) (not shown) between the polarization beam splitter 109 and the spatial light modulator 103, an optimum polarization direction with respect to the spatial light modulator 103 is obtained. To compensate.

  The modulated light that has returned to the polarization beam splitter 109 via the spatial light modulation element 103 is projected in the polarization beam splitter 109 according to the polarization direction, and returns to the first and second lens arrays 105 and 106 side. It is separated into an optical path incident on the lens. And only the light of the polarization direction corresponding to the white information of image information is projected as an image.

  With this configuration, the image display apparatus enlarges and displays the image information displayed by the spatial light modulator 103.

  FIG. 5 is a side view showing a schematic configuration of a so-called “rod integrator type” conventional image display apparatus.

  Also in this image display device, as shown in FIG. 5, illumination light emitted from the light source 101 is irradiated onto the spatial light modulation element 103 via the illumination optical system 102 to illuminate the spatial light modulation element 103. I am doing so. This image display apparatus is a “rod integrator type” image display apparatus, and uses an illumination optical system 102 that superimposes and illuminates the spatial light modulation element 103 and that includes a rod integrator.

  In this image display device, as shown in FIG. 5, the illumination light emitted from the light source 101 is reflected by the reflector 104, and is condensed and emitted in the optical axis direction. The illumination optical system 102 includes a glass rod 110 as a rod integrator, an exit lens 111, an overlapping lens 107, and a condenser lens 108. In this illumination optical system 102, the illumination light condensed and irradiated on the incident surface of the glass rod 110 by the reflector 104 enters the glass rod 110, and is repeatedly superimposed on the glass rod 110 by repeating total reflection. The emitted light has a uniform distribution. The outgoing lens 111 into which the outgoing light from the glass rod 110 is incident condenses the outgoing light from the glass rod 110 on the overlapping lens 107. A plurality of tertiary light source images corresponding to the number of reflections in the glass rod 110 are formed by the overlapping lens 107. In this way, the glass rod 110, the exit lens 111, and the superimposing lens 107 constitute an illumination optical system 102 that superimposes and illuminates the spatial light modulator 103 through the condenser lens 108 and the polarization beam splitter 109.

  In this image display device, modulated light that has returned to the polarization beam splitter 109 via the spatial light modulation element 103 is returned to the glass rod 110 side according to the polarization direction in the polarization beam splitter 109, and a projection lens (not shown). And the optical path incident on the light.

  Also in this image display device, a light beam whose incident angle is shifted in a direction orthogonal to a plane including the incident optical axis and the outgoing optical axis with respect to the polarizing beam splitter 109 is polarized after being transmitted through the polarizing beam splitter 109. The direction deviates from the optimum direction in the spatial light modulator 103. Therefore, by arranging a λ / 4 plate (quarter wavelength plate) (not shown) between the polarization beam splitter 109 and the spatial light modulator 103, an optimum polarization direction with respect to the spatial light modulator 103 is obtained. To compensate.

  By the way, in the conventional image display apparatus, size reduction of the apparatus and high brightness of the projected display image are required. Therefore, in these image display devices, the diameter of the illumination light in the illumination optical system 102 is increased in order to illuminate the spatial light modulation element 103 with a short optical path using a wider range of light. The F value tends to be small.

  On the other hand, since the polarization beam splitter 109, the λ / 4 wavelength plate, and the spatial light modulator 103 each have an incident angle dependency, optimal polarization modulation can be performed with respect to a light beam having a smaller incident angle. . Therefore, a higher contrast display image can be obtained as the F value of the illumination optical system 102 or the imaging optical system is larger.

  That is, the increase in brightness of the display image and the increase in contrast are in a contradictory relationship with respect to the F value of the illumination optical system 102 and the like. Here, when the usage environment is bright, it is preferable to obtain a high-brightness display image even if the display image contrast is slightly reduced. Conversely, when the usage environment is sufficiently dark, the display image It is preferable that a high-contrast display image is obtained even if the luminance of the image is slightly reduced.

  Therefore, as described in Patent Document 1 and Patent Document 2, an image display apparatus that allows a user to adjust the balance between luminance and contrast of a display image according to the brightness of a use environment. Proposed. This image display device includes a variable aperture stop that blocks a part of the light beam between the first and second lens arrays 105 and 106 and controls the cross-sectional area of the light beam. This variable aperture stop is configured by movably arranging a pair of stop plates that shield light beams between the first and second lens arrays 105 and 106, and by moving these stop plates, the contrast of a display image is increased. In addition, the brightness can be adjusted.

  Incidentally, the image display apparatus shown in FIGS. 4 and 5 is for monochrome display. In the color display image display device, the light from the illumination optical system 102 is decomposed into RGB (the three primary colors of red, green, and blue), and the RGB light is modulated by the corresponding spatial light modulation elements, and then the RGB light is converted. Are combined and projected.

  In such a color display image display apparatus, it is necessary to perform color balance (white balance) adjustment for adjusting the proportion of RGB light. Such color balance adjustment is performed by adjusting the magnitude of an electric signal for controlling each of the RGB liquid crystal light valves. For example, the amount of transmitted light increases in accordance with the magnitude of the electrical signal applied to the spatial light modulator.

For example, when the color temperature is set high, the electrical signal of RG is reduced to suppress the modulation amount of the liquid crystal of RG so that the amount of light of RG is relatively small with respect to B. Further, when the color temperature is set low, the electrical signal of the BG is reduced to suppress the modulation amount of the liquid crystal of the BG so that the amount of light of the BG is relatively small with respect to R.
JP-A-5-303085 JP 2001-142028 A

  By the way, in the color balance adjustment in the above-described color display image display apparatus, it is ideal if both the white level and the black level can be adjusted. However, in the electrical adjustment, only the white level side is adjusted. I can't. Therefore, by performing such color balance adjustment, the contrast of the display image is reduced.

  Therefore, the present inventors have provided a filter that attenuates and transmits only components in an arbitrary wavelength band in an illumination optical system as an image display device that can adjust the color temperature while improving the contrast of a display image. Propose what you have.

  In the illumination optical system including such a filter, it is conceivable to further adjust the color temperature while improving the contrast of the display image by providing the variable aperture stop as described above.

  FIG. 6 is a side view showing the configuration of an image display apparatus that can adjust the color temperature while improving the contrast of the display image.

  As shown in FIG. 6, this image display device attenuates only the variable aperture stop 112 and components in an arbitrary wavelength band between the first and second lens arrays 105 and 106 in the image display device described above. It is comprised by providing the filter 113 which permeate | transmits.

  FIG. 7 is a front view showing the positional relationship between the variable aperture stop and the filter in the image display apparatus shown in FIG.

  In this image display device, the filter 113 is disposed so that the peripheral portion of the light beam between the first and second lens arrays 105 and 106 is transmitted, as shown in FIG. The variable aperture stop 112 is configured such that a pair of stop plates that shield light beams between the first and second lens arrays 105 and 106 are movably disposed.

  In the image display device including the variable aperture stop 112 and the filter 113 as described above, as shown in (b) and (c) in FIG. Even when the aperture is narrowed, a decrease in the luminance of the display image can be suppressed, and as shown in FIG. 4A, the filter 113 can be used even when the aperture of the variable aperture stop 112 is opened with priority on the luminance. As a result, the color temperature of the display image is adjusted while improving the contrast, so that a reduction in contrast should be suppressed.

  However, in this image display device, there is a risk that the color temperature may change as the brightness and contrast of the display image are adjusted. In other words, in this image display device, when the aperture area of the variable aperture stop 112 is adjusted, the balance between the luminous flux that is incident on the filter and the luminous flux that is not incident is lost among the illumination light, so that the RGB balance is lost, and the illumination light is lost. The color temperature may change.

For example, when the filter 113 has a characteristic of attenuating the G (green) and B (blue) components, the variable aperture stop 112 is fully opened as shown in FIG. Assume that the ratio of RGG in the illumination light is R: G: B and the color temperature of the illumination light is K ₁ when neither the transmitted illumination light nor the illumination light that does not pass through the filter 113 is blocked. Then, as shown in FIG. 4B, when the variable aperture stop 112 is slightly stopped and only a part of the illumination light transmitted through the filter 113 is blocked, the ratio of RGG in the illumination light is R ': G: B becomes (∵R'<R), the color temperature of the illumination light becomes _{K 2.} Furthermore, as shown in FIG. 4C, the variable aperture stop 112 is further stopped, and not only a part of the illumination light that passes through the filter 113 but also a part of the illumination light that does not pass through the filter 113 is blocked. In this state, the ratio of RGG in the illumination light is R ″: G ′: B ′ (∵R ″ <R ′ <R, G ′ <G, B ′ <B), and the color temperature of the illumination light is K ₃

  Therefore, the present invention has been proposed in view of the above-described circumstances, and a case where priority is given to contrast of a display image and a case where priority is given to luminance is selected according to the use environment (ambient brightness). An image display apparatus capable of suppressing a decrease in luminance even when priority is given to contrast, and a reduction in contrast even if priority is given to luminance, and adjusting the contrast and luminance An object of the present invention is to provide an image display device in which the color temperature of illumination light is not changed.

  In order to solve the above-described problems and achieve the above object, an image display device according to the present invention includes a white light source in an image display device that displays an image displayed by a spatial light modulation element via an imaging optical system. An illumination optical system that receives illumination light emitted from the white light source to form a plurality of secondary or tertiary light source images of the white light source, and the illumination light that has passed through the illumination optical system is divided into three primary colors. Color separation means for making each light incident on a spatial light modulation element that modulates the light, and illumination light that has passed through the color separation means is incident, and a plurality of secondary or tertiary light source images of a white light source are superimposed by the illumination optical system. The spatial light modulation element that is illuminated by being formed and modulates the illumination light, the color synthesis means that synthesizes the modulated light of the three primary colors modulated by the spatial light modulation element, and the modulated light that has passed through the color synthesis means Is incident on the space light An imaging optical system that forms an image displayed by the modulation element, and an illumination optical system or an imaging optical system that has a variable aperture area and passes through by blocking part of the illumination light or modulated light. A variable aperture stop that controls the cross-sectional area of the luminous flux of the illumination light, and a filter that attenuates and transmits a component of an arbitrary wavelength band for a part of the illumination light. Of the illumination light that passes through the variable aperture stop, the filter The light quantity ratio between the illumination light that is incident and the illumination light that is not incident on the filter is characterized in that it is always maintained constant irrespective of the degree of aperture of the variable aperture stop.

  In the image display device according to the present invention, the ratio of the amount of illumination light that enters the filter and the illumination light that does not enter the filter out of the illumination light that passes through the variable aperture stop is always independent of the aperture of the variable aperture stop. Since it is maintained constant, the color temperature of the illumination light is kept substantially constant and the color balance of the display image changes when the contrast and brightness of the display image are adjusted by increasing or decreasing the aperture area of the variable aperture stop. There is nothing to do.

  That is, the present invention is an image display device capable of selecting a case where priority is given to the contrast of a display image and a case where priority is given to luminance according to the use environment (ambient brightness). Even if the brightness is reduced, the decrease in contrast can be suppressed even if priority is given to the brightness, and the color temperature of the illumination light does not change even if the contrast and brightness are adjusted. An apparatus can be provided.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an image display device according to an embodiment of the invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a side view showing the configuration of the image display apparatus according to the present embodiment.

  The image display device includes a light source 11 and a reflector 12 that reflects light emitted from the light source in the direction of the optical axis L0. As the light source 11, a light source that emits white light such as a high-pressure mercury lamp or a metal halide lamp is used. The reflector 12 has a rotating paraboloidal reflecting surface with the optical axis L0 as an axis, reflects the light emitted from the light source 11 by the reflecting surface, and emits it as illumination light parallel to the optical axis L0.

  The illumination light passes through the collimator lens 13 and the UV / IR (ultraviolet light and infrared light) cut filter 14 and enters the first lens array (fly eye lens) 15 constituting the illumination optical system. The UV / IR cut filter 14 blocks infrared light and ultraviolet light unnecessary for image display, thereby preventing heat generation of the optical system at the subsequent stage.

  The illumination light that has passed through the first lens array 15 is incident on the second lens array (fly eye lens) 16. A variable aperture stop 17 and a filter 18 are provided between the first lens array 15 and the second lens array 16. Illumination light emitted from the second lens array 16 is incident on a color separation / combination block 23 serving as a color separation unit and a color synthesis unit via a PS combiner 19, a superposition lens 20, a condenser lens 21, and a polarizer 22. .

  The first and second lens arrays 15 and 16 are similar to the liquid crystal light valves 24R, 24G, and 24B, which are spatial light modulators described later, so that the reflector 12 spatially divides the aperture from which the light beam is emitted. A plurality of shaped lens cells are two-dimensionally arranged. The first lens array 15 condenses illumination light on the lens cells of the second lens array 16 respectively corresponding to the lens cells, and the lens cells of the first lens array 15 are placed on the second lens array 16. The same number of secondary light source images are formed.

  For each lens cell, the second lens array 16 matches the image of the lens cell opening of the corresponding first lens array 15 with the surfaces of the liquid crystal light valves 24R, 24G, and 24B. The lens cells are overlapped on the liquid crystal light valves 24R, 24G, and 24B.

  The variable aperture stop 17 is configured by movably arranging a pair of stop plates that shield the light flux between the first and second lens arrays 15 and 16, and by moving these stop plates, the image display device The contrast and brightness of the displayed image can be adjusted.

  The filter 18 removes a component in a predetermined wavelength region that lowers the level of a part of the illumination light (for example, G (green) component and B (blue) component) transmitted through the first and second lens arrays 15 and 16. Attenuate and transmit the remaining light flux (for example, R (red) component) as it is.

  The PS combiner 19 is an optical element having a flat plate shape in which a plurality of polarization beam splitters are arranged in parallel, and emits light with the polarization direction of incident light aligned in a certain direction. The polarizer 22 is an optical element that rotates the polarization directions of the R component light and the B component light by 90 °.

  The overlapping lens 20 makes the center of the image of each lens cell of the first lens array 15 coincide with the center of the liquid crystal light valve 24R, 24G, 24B, and the image of each lens cell of the first lens array 15 is the liquid crystal light valve. It is made to overlap on the display surface of 24R, 24G, 24B.

  The condenser lens 21 allows illumination light (modulated light) that has passed through the liquid crystal light valves 24R, 24G, and 24B to enter the direction of the entrance pupil of the projection lens 26 that serves as an imaging optical system.

  The color separation / combination block 23 separates the incident light into RGB (the three primary colors of red, green, and blue) and makes the light incident on the liquid crystal light valves 24R, 24G, and 24B corresponding to the respective colors, and these liquid crystal light valves 24R, 24G, and 24B. This is an optical system for synthesizing the RGB light modulated by. That is, the illumination light emitted from the color separation / synthesis block 23 is applied to the liquid crystal light valves 24R, 24G, and 24B. The color separation / combination block 23 can have various configurations using a prism or a dichroic mirror. In this embodiment, the color separation / synthesis block 23 includes four polarization beam splitters 23a, 23b, 23c, and 23d.

  In the color separation / combination block 23, the illumination light incident on the first polarization beam splitter 23a is deflected by the polarization separation film through which the G component light is transmitted and the R component light and B component light are reflected. The G component light transmitted through the polarization separation film of the first polarization beam splitter 23a is further transmitted through the second polarization beam splitter 23b and irradiated to the green liquid crystal light valve 24G. The R component light and the B component light reflected by the polarization separation film of the first polarization beam splitter 23a enter the third polarization beam splitter 23c. At this time, the polarization direction of the R component light is rotated by 90 ° by an optical element (not shown). In the polarization separation film of the third polarization beam splitter 23c, the R component light is transmitted and the B component light is reflected and deflected. The R component light transmitted through the polarization separation film of the third polarization beam splitter 23c is applied to the red liquid crystal light valve 24R. Further, the B component light reflected by the polarization separation film of the third polarization beam splitter 23c is applied to the blue liquid crystal light valve 24B.

  In this image display device, a plurality of secondary light source images are formed by the second lens array 16, and a plurality of tertiary light source images are formed by the overlapping lens 20 in the liquid crystal light valves 24R, 24G, and 24B. . This tertiary light source image illuminates the liquid crystal light valves 24R, 24G, and 24B in a superimposed manner. In this image display apparatus, the illumination optical system that performs such superposition illumination includes the first and second lens arrays 15 and 16 and the superposition lens 20.

  Each of the liquid crystal light valves 24R, 24G, and 24B includes a liquid crystal plate formed by two-dimensionally arranging a plurality of liquid crystal cells, and controls the polarization direction of illumination light transmitted through each liquid crystal cell. Is a reflective liquid crystal spatial light modulator that reflects the modulated light that is polarization-modulated according to the display image by reflecting the light from the back reflector.

  The modulated light modulated by the red liquid crystal light valve 24R returns to the third polarization beam splitter 23c, is reflected by the polarization separation film of the third polarization beam splitter 23c, and has a polarization direction of 90 ° by an optical element (not shown). It is rotated and incident on the fourth polarization beam splitter 23d. The red modulated light passes through the polarization separation film of the fourth polarization beam splitter 23d and is emitted from the fourth polarization beam splitter 23d.

  The modulated light modulated by the green liquid crystal light valve 24G returns to the third polarization beam splitter 23c, passes through the polarization separation film of the third polarization beam splitter 23c, and enters the fourth polarization beam splitter 23d. Incident. The green modulated light passes through the polarization separation film of the fourth polarization beam splitter 23d and is emitted from the fourth polarization beam splitter 23d.

  Then, the modulated light modulated by the blue liquid crystal light valve 24G returns to the second polarization beam splitter 23b, is reflected by the polarization separation film of the second polarization beam splitter 23b, and is reflected by the fourth polarization beam splitter 23d. Incident. The blue modulated light is reflected by the polarization separation film of the fourth polarization beam splitter 23d and is emitted from the fourth polarization beam splitter 23d.

  In this way, only the blue modulated light of the RGB modulated light emitted from the fourth polarizing beam splitter 23d is rotated by 90 ° by the optical element (not shown) and is incident on the analyzer (polarizing plate) 25. The The analyzer 25 transmits only P-polarized light. Accordingly, light that is not modulated by the liquid crystal light valves 24R, 24G, and 24B is blocked by the analyzer 25. The modulated light that has passed through the analyzer 25 is incident on the projection lens 26. The projection lens 26 projects the modulated light transmitted through the analyzer 25 toward a screen (not shown) to form an image.

  FIG. 2 is a front view showing the positional relationship between the variable aperture stop and the filter.

  The filter 18 described above is disposed in the vicinity of the second lens array 16 where the secondary light source image is formed, and as shown in FIG. 2A, a lens array for attenuating components in a predetermined wavelength band. The second lens array 16 is disposed on both opposing sides corresponding to the openings. Here, in FIG. 1, the light rays a, b, f, and g in the illumination light are substantially only the R light component, and the light rays c, d, and e are white light in which each color light of RGB is aligned. Accordingly, the illumination light superimposed in each of the liquid crystal light valves 24R, 24G, and 24B is attenuated in the G component and the B component, and becomes light having a low color temperature. In addition, for the G component and the B component, the peripheral portion of the illumination light is blocked and the F value of the illumination optical system is substantially increased compared to the R component, so that the contrast in the display image is improved. is doing.

  As for the positional relationship between the variable aperture stop 17 and the filter 18, as shown in FIGS. 2A and 2B, the variable aperture stop 17 includes the second lens array 16 in which the filter 18 is disposed. The opening area is arranged so as to increase or decrease from the direction perpendicular to both sides. That is, the boundary line of the filter 18 is a direction along the moving direction of the light shielding plate that forms the variable aperture stop 17. Therefore, even if the variable aperture stop 17 increases or decreases the aperture area, the light quantity ratio between the light rays a, b, f, g and the light rays c, d, e in FIG. 1 does not change, that is, the color of the illumination light. The temperature does not change.

  The secondary light source image on the second lens array 16 has a light amount distribution, and in the arrangement of the filters 18 shown in FIGS. 2A and 2B, each color is obtained when the variable aperture stop 17 is opened and closed. When the light quantity ratio changes, as shown in FIG. 2C, the light quantity ratio of each color light is always constant regardless of the aperture condition of the variable aperture diaphragm 17 even if the variable aperture diaphragm 17 is opened and closed. The arrangement position of the filter 18 may be adjusted so as to be maintained. At this time, it is preferable that the boundary line of the filter 18 matches the cell boundary line without passing through the inside of the cell of the second lens array 16.

  Further, as shown in FIG. 2D, the arrangement position of the filter 18 is a radial position centered on the optical axis, and the variable aperture stop 17 is a circular or polygonal blade stop (iris stop). Also good.

  Further, as shown in FIG. 2 (e), the variable aperture stop 17 is arranged so that the aperture area is increased or decreased from the same direction as both side portions of the second lens array 16 in which the filter 18 is arranged. Even if the variable aperture stop 17 is opened and closed by moving the filter 18 according to the movement of the light shielding plate of the variable aperture stop 17, the light quantity ratio of each color light is always constant regardless of the stop condition of the variable aperture stop 17. It can also be maintained. In this case, the moving amount of the filter 18 is preferably proportional to the moving amount of the light shielding plate of the variable aperture stop 17 and smaller than the moving amount of the light shielding plate. That is, in (e) of FIG. 2, if the width of the filter 18 is B when the aperture diameter of the variable aperture diaphragm 17 is A, the aperture diameter is A ′ by narrowing the variable aperture diaphragm 17. In some cases, the width of the filter 18 is set to B ′ so that A: B is equal to A ′: B ′.

  In this embodiment, the filter 18 is disposed between the first and second lens arrays 15 and 16, but is disposed between the second lens array 16 and the overlapping lens 20. It may be.

  Further, the image display device is not limited to the above-described “lens array type” image display device, and a glass rod and an emission lens are arranged in place of the first and second lens arrays 15 and 16. Thus, the “rod integrator type” image display apparatus may be configured.

[Second Embodiment]
FIG. 3 is a side view showing the configuration of the image display apparatus according to the second embodiment of the present invention.

  As shown in FIG. 3, in this image display device, the filter 18 is arranged in the vicinity of the second lens array 16 in the same manner as in the first embodiment, and the variable aperture stop 17 It may be arranged on the pupil.

  Also in this configuration, similarly to the first embodiment described above, the variable aperture stop 17 has an aperture area from a direction perpendicular to both sides of the second lens array 16 in which the filter 18 is disposed. If the variable aperture stop 17 increases or decreases the aperture area, the color temperature of the light flux in the display image can be prevented from changing.

1 is a side view showing a configuration in a first embodiment of an image display device according to the present invention. It is a front view which shows the positional relationship of the variable aperture stop and filter in the said image display apparatus. It is a side view which shows the structure in 2nd Embodiment of the image display apparatus which concerns on this invention. It is a side view which shows schematic structure of the conventional image display apparatus of what is called a "lens array system." It is a side view showing a schematic configuration of a so-called “rod integrator type” conventional image display device. It is a side view which shows the structure of the conventional image display apparatus which enabled it to adjust color temperature, improving the contrast of a display image. FIG. 7 is a front view showing a positional relationship between a variable aperture stop and a filter in the image display device shown in FIG. 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Light source 15 1st lens array 16 2nd lens array 17 Variable aperture stop 18 Filter 20 Superposition lens 21 Condenser lens 23 Color separation / synthesis block 23a 1st polarizing beam splitter 23b 2nd polarizing beam splitter 23c 3rd Polarizing beam splitter 23d Fourth polarizing beam splitter 24R Red liquid crystal light valve 24G Green liquid crystal light valve 24B Blue liquid crystal light valve 26 Projection lens

Claims (1)

In an image display device that displays an image displayed by a spatial light modulation element via an imaging optical system,
A white light source,
An illumination optical system that receives illumination light emitted from the white light source and forms a plurality of secondary or tertiary light source images of the white light source;
Color separation means for splitting the illumination light that has passed through the illumination optical system into three primary colors and making the light incident on a spatial light modulator that modulates the three primary colors, respectively;
Illumination light that has passed through the color separation means is incident and illuminated by the illumination optical system formed by superimposing a plurality of secondary or tertiary light source images of the white light source, and modulates the illumination light. A spatial light modulator;
Color synthesizing means for synthesizing modulated light of the three primary colors modulated by the spatial light modulator;
An imaging optical system that receives the modulated light that has passed through the color synthesizing unit and forms an image displayed by the spatial light modulator;
Provided in the illumination optical system or the imaging optical system, the aperture area is variable, and by cutting off a part of the illumination light or the modulated light, a light flux of the passing illumination light is interrupted. A variable aperture stop for controlling the area;
A filter that attenuates and transmits a component in an arbitrary wavelength band for a part of the illumination light; and
Of the illumination light passing through the variable aperture stop, the light quantity ratio between the illumination light incident on the filter and the illumination light not incident on the filter is always maintained constant regardless of the diaphragm condition of the variable aperture stop. An image display device characterized by the above.

Images