JP4513516B2 - Video display device - Google Patents

Description

  The present invention relates to a projection-type image display device that forms an optical image by modulating the light intensity of light emitted from a light source with a light valve such as a liquid crystal panel or a micromirror array panel, and projects the optical image on a screen. More particularly, the present invention relates to a color separation element that spatially separates a plurality of color lights irradiated to a light valve from light from a light source.

  Conventionally, after light from a light source passes through an integrator element and a collimator lens, R (red) light, G (green) light, and B (blue) are used using a color separation element composed of a plurality of dichroic mirrors. Separate into light. Then, the strips irradiated with each color light are irradiated with each color light at the same time by changing the optical path of each separated color light using one reflection type rotating polyhedron and changing the light path. For example, a single-plate projection-type image display device described in Patent Document 1 below is known in which the location of a strip (band) region is sequentially moved (scrolled) on a light valve in a certain direction.

  As a color separation element used in the single-plate projection-type image display device, for example, there is a color prism that combines a plurality of dichroic prisms and a reflecting surface described in Patent Document 2 below.

  Further, as a single-plate projection type image display device, there is also known a color sequential display method in which R, G, B light is sequentially projected onto a light valve in a time-division manner to perform color display. A color wheel having three fan-shaped R, G, and B color regions divided into three in the circumferential direction is generally used as a color separation element of this type of single-plate projection type video display device. By rotating this color wheel, the light from the light source is separated into, for example, R, G, and B light in a time-sharing manner. At this time, if an area that transmits W (white) light is added to the color wheel, the luminance is increased. Can be improved. This is well known and disclosed in, for example, Patent Document 3 below.

JP 2001-350112 A Japanese Patent Laid-Open No. 2003-149738 Japanese Patent Laid-Open No. 2004-191685

  The inventors of the present application use W light in a color prism that combines a plurality of dichroic prisms and a reflecting surface, which is a color separation element used in a single-plate projection-type image display device using a rotating polyhedron for the purpose of improving luminance. Study was carried out.

  FIG. 7 is a configuration diagram of a color separation element that separates R, G, B, and W light. FIG. 7A is a configuration diagram of the studied color separation element, and FIG. 7B is a conventional color prism. It is a block diagram of a color separation element.

  In FIG. 7A, the color separation element 55 includes a W prism 55a in which, for example, a half mirror film is formed at the interface between two triangular prisms, and half of incident light (W light) is transmitted and half is reflected. The R prism 55b, which is a dichroic prism that reflects and separates the first color light (here, R light) of the W light reflected by the W prism 55a, and the first light out of the light transmitted through the R prism 55b. The G color prism 55c, which is a dichroic prism that reflects and separates the second color light (here G light), and the third color light (here, B light) out of the light transmitted through the G prism 55c is separated. And a B prism 55d which is a dichroic prism.

  The emission surface shape of each prism is substantially similar to the display area of a light valve (not shown) divided into four substantially equal strip-shaped (band-like) areas whose long sides are parallel to the long side of the light valve. It is supposed to be.

  Then, light from a light source (not shown) is made uniform in light quantity distribution by an integrator (not shown), is incident on the W prism 55a of the color separation element 55, the W prism 55a, the R prism 55b, The G prism 55c and the B prism 55d perform color separation into W, R, G, and B light.

  Further, the conventional color separation element 56 is a light that is reflected by the R transmission prism 56b, which is a dichroic prism that transmits the first color light (R light) of the incident light (W light), and the R transmission prism 56b. Among them, the G color prism 56c, which is a dichroic prism that reflects and separates the second color light (G light), and the third color light (B light) out of the light transmitted through the G prism 56c is separated. And a B prism 56d which is a dichroic prism.

  The emission surface shape of each prism is substantially similar to the display area of a light valve (not shown) divided into three substantially equal strip (band) areas whose long sides are parallel to the long side of the light valve. It is supposed to be.

  Light from a light source (not shown) is made uniform in light quantity distribution by an integrator (not shown), and is incident on the R transmission prism 56b of the color separation element 56, and the R transmission prism 56b and the G prism 56c. Then, the color is separated into R, G, B light by the B prism 56d.

  As described above, when the light from the light source is incident on one prism constituting the color separation element, the incident aperture size of the conventional color separation element 56 is about 33% compared to the panel size of the light valve 100%. However, the incident aperture size of the studied color separation element 55 is about 25%.

  That is, it was found that the light amount (transmittance) deteriorated more than originally estimated despite the addition of the W prism for improving the luminance.

  The present invention has been made in view of the above-described circumstances, and the object thereof is to add a color separation element for W light (W light is also considered as one of the colors and expressed as a color separation element). An object of the present invention is to provide a color separation element capable of improving the utilization efficiency and increasing the luminance of an image and a projection type image display apparatus using the same.

In order to achieve the above object, for example, it may be configured as described in the claims.

  ADVANTAGE OF THE INVENTION According to this invention, the utilization efficiency of light can improve and it can provide a high-intensity projection type video display apparatus.

  Hereinafter, the best mode of the present invention will be described in detail with reference to the drawings. In addition, using a rotating polyhedron (in the following description, a reflective polyhedron), the strip-shaped (strip-shaped) emission shape of each color light spatially separated into a plurality of colors by a color separation element is different on the light valve. Since a scroll technique for simultaneously irradiating a place and moving (scrolling) the irradiation place of the strip-shaped color light region in a predetermined direction on the light valve is described in detail in Patent Document 1, details thereof are omitted.

  FIG. 2 is a block diagram of an optical unit showing a first embodiment according to the present invention.

  The optical unit is a light source, an integrator that uniformizes the light amount distribution of the light from the light source, and an optical image obtained by modulating the light intensity of the light whose light amount distribution has been made uniform by the integrator according to an input video signal. The optical system includes at least a light valve to be formed and a projection lens for enlarging and projecting the optical image. A projection-type video display device is an optical unit that is housed in a casing together with a video processing circuit, a power supply circuit, and the like.

  In FIG. 2, 1 is a lamp that emits substantially white light, 2 is a reflector that reflects light from the lamp 1, and the lamp 1 and the reflector 2 constitute a light source. Reference numeral 3 denotes a polarization beam splitter of a polarization conversion element that aligns the polarization direction with a predetermined polarization direction (here, S-polarized light), and 4 denotes an integrator for uniformizing the light amount distribution in which the exit aperture is larger than the entrance aperture according to the present invention. The light pipe 5 is a color separation element that spatially separates the light from the light pipe 4 according to the present invention into W, R, G, and B light, and 6 is a total reflection that bends the light emitted from the color separation element 5. Mirror 10 is a flat polarizing beam splitter, 12 is a reflection type liquid crystal panel, which is a light valve (image display element), 13 is a reflection type rotating polyhedron, and 14, 15 and 16 reflect the shape of the exit surface of the color separation element 5. An imaging lens group that forms an image on the liquid crystal panel 12, an incident-side polarizing plate that transmits polarized light (here, S-polarized light) in a predetermined polarization direction, and 17b that has a polarization direction different from that of the incident-side polarizing plate 17a An exit-side polarizing plate that transmits light (here, P-polarized light), 18 is a polarizing beam splitter prism, 19 is a λ / 2 wavelength plate that converts the polarization direction disposed in front of the incident-side polarizing plate 17a, and 4b is polarized light. A λ / 4 wavelength plate for adjusting the direction, 4c is disposed between the polarizing beam splitter prism 18 and the reflective liquid crystal panel 12 to improve contrast, and 23 is a projection lens.

  Here, in order to facilitate the following description, for convenience, an orthogonal coordinate system as shown in FIG. 2 is introduced. That is, the optical axis direction of the light pipe 4 is the X axis, the rotational axis direction of the reflective rotary polyhedron 13 is the Z axis, the X axis, and the axis orthogonal to the Z axis is the Y axis.

  Therefore, the display surface of the reflective liquid crystal panel 12 is parallel to the XZ plane, as is apparent from FIG. The long side direction of the reflective liquid crystal panel 12 is parallel to the Z axis perpendicular to the paper surface of FIG. 2, and the short side direction is parallel to the X axis.

  In the optical unit configured as described above, the white light from the light source obtained by reflecting the light emitted from the lamp 1 by the reflector 2 is a polarization beam splitter that is a polarization conversion element for aligning the polarization direction of the light. 3 is incident. Here, the light whose polarization direction is aligned with, for example, S-polarized light is incident on the light pipe 4 which is an integrator for uniformizing the light amount distribution. The light pipe 4 makes the light quantity distribution uniform by multiple reflection of incident light inside. The light emitted from the light pipe 4 is simultaneously irradiated onto an incident surface of a predetermined region (details will be described later) of the color separation element 5.

  The configurations and functions of the light pipe 4 and the color separation element 5 of the present invention will be described in detail later with reference to FIG.

  The light applied to the color separation element 5 is spatially separated in the Y-axis direction into W light and three color lights of R, G, and B light. Accordingly, four scroll bands whose long sides are parallel to the long side of the panel (parallel to the Z axis) are irradiated on the reflective liquid crystal panel 12.

  Each of the separated color lights (including W light) has its optical path bent by the total reflection mirror 6 and enters the flat polarizing beam splitter 10. Since the incident light is S-polarized light, it is reflected, travels toward the reflective rotary polyhedron 13, is reflected by the reflective rotary polyhedron 13, and then enters the flat polarizing beam splitter 10 again. Since the λ / 4 wavelength plate 4b is inserted between the flat polarizing beam splitter 10 and the reflective rotary polyhedron 13, the polarization direction is changed from S-polarized light to P-polarized light while reciprocating between them. The polarized light beam splitter 10 is incident as P-polarized light. This time, each color light is transmitted through the plate-type polarizing beam splitter 10, but after being converted into S-polarized light by the λ / 2 wavelength plate 19, it is transmitted through the incident-side polarizing plate 17a and reflected by the polarizing beam splitter prism 18. The reflective liquid crystal panel 12 is irradiated. At this time, as shown in FIG. 6A, the scroll bands 12W, 12R, 12G, and 12B of each color light (including W light) are irradiated to different places on the reflective liquid crystal panel 12, respectively. Each scroll band is scrolled in parallel to the short side direction (X-axis direction) of the reflective liquid crystal panel 12.

  The light of the optical image (video) converted from S-polarized light to P-polarized light emitted from the reflective liquid crystal panel 12 passes through the polarization beam splitter prism 18 and then passes through the output-side polarizing plate 17b before being projected. The image is enlarged and projected through a lens 23 onto a screen (not shown).

  As the light valve, a reflective liquid crystal panel is used in this embodiment. However, the present invention is not limited to this, and any one of a transmissive liquid crystal panel, a ferroelectric liquid crystal panel, a micromirror array panel, and the like is used. Can be used as appropriate. Of course, it goes without saying that an optimal optical system is selected in accordance with the light valve to be used.

  Next, the color separation element 5 will be described in detail with reference to FIG. FIG. 1 is an enlarged view of a main part in the vicinity of the color separation element in FIG. 2, and FIG. 1 (a) is a diagram for explaining the operation of the color separation element according to the first embodiment of the present invention, and FIG. It is a figure which shows the output surface shape. In FIG. 1, the polarizing beam splitter 3 is omitted for convenience of explanation.

  In FIG. 1, a color separation element 5 is a first color separation element that transmits white light (W light) incident from the light pipe 4 as it is (guides W light as a color separation element). ) And a color prism 5f which is a second color separation element that separates the white light (W light) incident from the light pipe 4 into the three primary colors of light. Is an R prism 5b, which is a dichroic prism that transmits and separates first color light (here, R light) of incident light (W light), and second color light among light reflected by the R prism 5b. The G prism 5c, which is a dichroic prism that reflects and separates (here G light), and the dichroic pre that reflects and separates the third color light (here, B light) out of the light transmitted through the G prism 5c. Consisting of B prism 5d is beam. As the B prism 5d, in place of the dichroic prism that reflects the B light, although the color purity is somewhat deteriorated, for example, a prism having a reflecting action by an aluminum koto surface may be used.

  Since the W rod lens 5a of the color separation element 5 is totally reflected and guided by the air interface on the side surface, the W rod lens 5a and the color prism 5f (specifically, the R prism 5b) are opposed to each other. The W rod lens 5a and the color prism 5f of the color separation element 5 are held and fixed so that an air layer is formed between the side surfaces (the holding means is not shown).

  The light pipe 4 is an integrator that makes the light quantity distribution uniform, with the exit opening being larger than the entrance opening. The light incident from the light source is repeatedly reflected inside the light pipe, and the light quantity is substantially uniform at the exit opening. Distribution. Further, in the light pipe 4 used in the present invention, the size of the exit aperture is larger than that of the entrance aperture, and its cross-sectional area gradually increases toward the exit surface. The value becomes larger, and the divergent component of the ray angle can be reduced. That is, the light pipe 4 has an F value conversion function.

  The light pipe 4 and the color separation element 5 are held in close contact with each other by a holding unit (not shown). The light pipe 4 has an emission opening shape for W which is the first color separation element of the color separation element 5. The surface shape of the rod lens 5a and the incident surface of the first color light R prism 5b (that is, the incident surface of the color prism 5f, which is the second color separation element) are substantially equal to each other. Since the light pipe 4 and the color separation element 5 are substantially in close contact with each other, the light from the light pipe 4 can be efficiently guided to a predetermined area of the color separation element 5 without waste.

  As described above, since the light pipe 4 and the color separation element 5 are configured and arranged, the light (W light) whose light quantity distribution is uniformized by the light pipe 4 is apparent from FIG. The incident surfaces of the W rod lens 5a of the color separation element 5 and the R prism 5b for the first color light (that is, the incidence surface of the color prism 5f as the second color separation element) are simultaneously irradiated.

  The W light incident on the W rod lens 5a of the color separation element 5 is transmitted (guided) as it is and emitted. Further, the W light incident on the R prism 5b of the color prism 5f of the color separation element 5 is R, G, B light by the color prism 5f, that is, the R prism 5b, the G prism 5c, and the B prism 5d. Are separated and output.

  The exit surface shape of the color separation element 5 is the exit surface shape of each of the prisms 5b, 5c, 5d of the W rod lens 5a and the color prism 5f as shown in FIG. Are substantially equal to the reflective liquid crystal panel 12 in the form of four strip (band) regions 5aW, 5bR, 5cG, 5dB.

  As described above, the W rod lens 5a and the color prism 5f constituting the color separation element 5 (specifically, in this embodiment, the first color light separation prism adjacent to the W rod lens 5a). The light (W light) from the light source can be directly used as the W color by simultaneously making the light incident on the R prism), and the exit aperture shape of the light pipe 4 can be changed to the W rod lens of the color separation element 5. Etendue, which is the product of the area of the light beam and the solid angle of the light beam divergence, can be increased by making the surface ratio of the incident surface of 5a and the R prism 5b approximately equal to each other. As a result, the brightness can be increased.

  In the above description, the colors separated by the color prism 5f of the color separation element 5 are three colors of R, G, and B. However, a combination of Y (yellow), C (cyan), and M (magenta) is also possible. Good. Also, a combination of three or more colors, for example, a combination of R, Y, G, C, M, or a combination of R, O (orange), G, B, V (purple) may be used. The number of dichroic prisms constituting the color prism of the separation element is four or more, and the scroll band on the light valve is five or more. If multiple colors of 3 or more are used, by increasing the number of colors, in the general xy chromaticity diagram, the displayable range of chromaticity that was represented by a triangle in 3 colors can be represented by a square. This has the effect of expanding the chromaticity expression range.

  Further, an IR cut filter, a trimming filter, and a UV cut filter may be appropriately attached to the emission surface of each prism of the color prism 5f as necessary. Specifically, an IR cut filter is attached to the R prism 5b, a trimming filter is attached to the G prism 5c, and a UV cut filter is attached to the B prism 5d to separate the R light, G light, and B light. Also good. By applying an IR cut filter, infrared rays can be removed and heat generation by infrared rays can be prevented, and by applying a trimming filter, bright lines of a lamp light source in the yellow wavelength range can be removed, thereby improving the color tone. . Further, by attaching a UV cut filter, there is an effect of removing ultraviolet rays and preventing deterioration of an optical component (for example, a polarizing plate) made of an organic material.

  In this embodiment, an air layer is provided between the W rod lens 5a of the color separation element 5 and the R prism 5b. However, the present invention is not limited to this. For example, aluminum may be vapor-deposited on one of the opposing side surfaces of the R prism 5b to form a reflection surface, and the W rod lens 5a and the R prism 5b may be joined with an adhesive (not shown), for example. . In this way, it is possible to ensure multiple internal reflection at the side surface of the R prism 5b side of the W rod lens 5a, and to eliminate the air layer, so that the color separation element 5 can be downsized. can do.

  In FIG. 1B, the four strip regions 5aW, 5bR, 5cG, and 5dB are substantially equal. However, the present invention is not limited to this, and when priority is given to chromaticity gradations. If necessary, the short side of the strip-like region 5aW may be shortened to make the region small, and the three strip-like regions 5bR, 5cG, 5dB may be enlarged substantially equally by that amount.

  In the above description, the long side direction of the reflective liquid crystal panel 12 is defined as the Z-axis direction, and the color separation element 5 spatially separates it in the Y-axis direction and is parallel to the short-side direction (X-axis direction) of the reflective liquid crystal panel. However, the present invention is not limited to this. For example, the short side direction of the reflective liquid crystal panel 12 ′ is taken as the Z-axis direction, as shown in FIG. You may make it scroll in parallel with a side direction (X-axis direction). If it does in this way, compared with the case of a present Example, the exit opening shape of the light pipe 4 can be brought close to a square, and light efficiency can be improved more.

  In FIG. 2, the light pipe 4 is used as an integrator, but the same effect can be obtained by a multi-lens array system as shown in FIG.

  FIG. 3 is a configuration diagram of an optical unit that uses a multi-lens array system instead of a light pipe as an integrator. 3, elements having functions common to those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 3, reference numerals 30 and 31 denote a first lens array and a second lens array that constitute a known multi-lens array system integrator, and 32 a polarization conversion element that aligns the polarization direction with a predetermined polarization direction (here, S polarization), Reference numerals 33 and 34 indicate the shape of each lens cell constituting the first lens array 30 together with the second lens array 31 on the incident surface of the color separation element 5 (that is, the W rod lens 5a and the R prism 5b). This is a condensing lens group that forms an image superimposed on the (incident surface). In general, the reflecting surface shape of the reflector 2 is, for example, an elliptical surface in the case of a rod lens, but a parabolic surface in the case of a multi-lens array method.

  The light beam from the light source is divided into a plurality of light beams by the first lens array and the second lens array, the polarization direction is aligned with the S-polarized light by the polarization conversion element 32, and the above-described colors are obtained by the condenser lens groups 33 and 34. Irradiation is performed by superimposing on a predetermined region of the separation element 5. Subsequent operations are the same as those in FIG.

  In the first embodiment, the rod lens is used as the W light separation element of the color separation means, but the present invention is not limited to this. A second embodiment using a mirror type light pipe whose inner surface is constituted by a reflection mirror as a W light separation element of the color separation means will be described below.

  FIG. 4 is a schematic configuration diagram of a color separation element according to a second embodiment of the present invention. FIG. 4A is a perspective view of the color separation element, and FIG. 4B is a line AA in FIG. FIG. Elements having the same functions in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 4, the color separation element 50 according to this embodiment includes a mirror type light pipe 50 a that transmits (guides) W light incident from the light pipe 4 as it is, and white light (W light) incident from the light pipe 4. The color prism 50f is a dichroic prism that separates R light, and a G prism 50c that is a dichroic prism that separates G light. , And a B prism 50d which is a dichroic prism for separating B light.

Mirror type light pipe 50a, as is clear from FIG. 4, the side surface excluding the color prism 50f side surface is the total reflection mirror 8, a color prism 50f side surface is surrounded by the side surface 50b ₁ of R prism 50b hollow It has become a pipe. The side surface 50b ₁ of R prism 50b of the mirror type light pipe 50a, for example aluminum is deposited, to constitute a metal reflection mirror. The mirror type light pipe 50a is fixed to the color prism 50f by holding means (not shown).

Therefore, W light incident from the light pipe 4 to the mirror type light pipe 50a is guided to the exit side is reflected by the metal reflection mirror side 50b ₁ of the total reflection mirror 8 and R prism 50b. W light that has entered the color prism 50f from the light pipe 4 is separated into R, G, and B light by the prisms 50b, 50c, and 50d, as in FIG.

  According to the present embodiment, the luminance can be improved as in the first embodiment, and unlike the first embodiment, an air layer is not required at the interface between the W light separating element and the color prism. The thickness of each separation element in the stacking direction can be reduced and the size can be further reduced.

  In the above, a color prism composed of a dichroic prism is used as a color separation element other than W light, but the present invention is not limited to this. A third embodiment using a flat dichroic mirror as a color separation element other than W light will be described below.

  FIG. 5 is a schematic configuration diagram of a color separation element showing a third embodiment using a flat dichroic mirror as a color separation element other than W light, and FIG. 5A is a perspective view of the color separation element. b) The figure is a cross-sectional view in a plane parallel to 42 in the figure (a).

  In FIG. 5, the color separation element 51 transmits, for example, a rod light W light separation element 51 a that directly transmits (guides) the W light incident from the light pipe 4, and white light (W light) incident from the light pipe 4. A color dichroic mirror 51f that separates the three primary colors of light. The color dichroic mirror 51f includes a flat plate type R dichroic mirror 51b that separates R light, a flat plate type dichroic mirror 51c that separates G light, It comprises a flat plate type dichroic mirror 51d for separating the B light.

  This embodiment is different from the first and second embodiments in that a color dichroic mirror composed of a flat plate type dichroic mirror is used in place of the color prism. Description is omitted.

  In FIG. 5, reference numerals 41 and 42 denote holding members that hold the color separation element 51, and the holding members 41 and 42 can position the optical component with high accuracy.

  In the above description, the dichroic mirror is used as an element for separating the B light. However, although the color purity is somewhat deteriorated, it goes without saying that it may be a total reflection mirror.

  In the embodiment described above, the light pipe 4 and the color separation element 51 as the light guide means are described as being fixedly arranged in the optical unit shown in FIG. 2, for example. However, the present invention is not limited to this. Absent. That is, it is apparent that the present invention is applicable even when the light pipe 4 and the color separation element 51 are detachable. For example, as shown in FIG. 8, when the arrangement area of the light pipe 4 and the color separation element 51 is A × B, when brightness is important, white light ( A color separation element 51a having an opening of (W light) having 25% of A is mounted. Then, a light pipe 4a having an opening on the emission side that is 50% of A is attached. Further, when emphasizing color reproducibility, as shown in FIG. 8 (b), a color separation element 51b having a white light (W light) opening of 16% of A is mounted. Then, the light pipe 4b whose opening on the emission side is 44% of A is attached.

  As described above, the light pipe 4 and the color separation element 51 are configured to be detachable, so that they can be used according to the usage environment.

FIG. 5 is an operation explanatory diagram of the color separation element according to the first embodiment of the present invention. It is a block diagram of the optical unit which shows 1st Example by this invention. It is a block diagram of the optical unit using the multi lens array system which shows another Example of the 1st Example by this invention. It is a schematic block diagram of the color separation element which shows the 2nd Example by this invention. It is a schematic block diagram of the color separation element which shows the 3rd Example by this invention. It is a figure explaining the operation | movement of the color light on the reflection type liquid crystal panel by this invention. It is an examination block diagram of the color separation element which isolate | separates into R, G, B, and W light. It is a block diagram of the light pipe and color separation element explaining the structure according to use environment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lamp, 2 ... Reflector, 3 ... Polarizing beam splitter, 4 ... Light pipe, 5 ... Color separation element, 12 ... Reflection type liquid crystal panel, 13 ... Reflection type rotation polyhedron, 23 ... Projection lens.

Claims (7)

A light source;
A light guide means for uniformizing a light quantity distribution of light from the light source;
A color separation element that separates light from the light guiding means into four or more color lights including white light;
An image display element that forms an optical image from the color light separated by the color separation element;
A projection lens for enlarging and projecting an optical image emitted from the image display element;
An image display device, wherein the light emitted from the light guide unit is guided to an opening of the white light separation unit and one opening of another color light separation unit of the color separation element. The video display device according to claim 1,
The white light separating portion is formed of a rod lens,
An image display device, wherein the other color light separation portion is formed of a dichroic prism. The video display device according to claim 2,
The rod lens and the dichroic prism have an integrated structure in which an air layer is provided on a joint surface between the rod lens and the dichroic prism. The video display device according to any one of claims 1 to 3,
The light emitting means has an exit opening substantially equal to an opening formed by combining an opening of the white light separating portion and one opening of the other color light separating portion. apparatus. The video display device according to any one of claims 1 to 4,
The image display device, wherein the light guide means is a light pipe having an exit aperture cross-sectional area larger than an entrance aperture cross-sectional area and having an F-number conversion function. The video display device according to any one of claims 1 to 5,
An image display device, wherein an opening of the white light separation unit and a cross-sectional area of one of the other color light separation units are different. The video display device according to any one of claims 1 to 6,
The video display device, wherein the light guide means and the color separation element are detachable from the optical unit.

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