JP2007279627A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector capable of obtaining a wide color reproduction area at a low cost. <P>SOLUTION: A color compositing optical system 40 includes: a first dichroic prism 41 for compositing R modulated light, G modulated light, and C modulated light; a second dichroic prism 42 for compositing the RGC composited light and B modulated light; and a glass member 43 for adjusting the optical length of a relay optical system. The second dichroic prism 42 composites a fourth-color modulation light, by transmitting the light of the wavelength region of the RGC light and reflecting B modulated light by means of a mirror face 42a that has the property of reflecting the light of the wavelength region of B light. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a projector that projects a color image by controlling light modulation for each of primary color lights of multiple colors.

  2. Description of the Related Art Conventionally, projectors that project a color image by separating light from a light source into RGB (red, green, and blue) three primary colors and controlling each primary color with a light valve are widely known.

  In addition, in order to realize a wider color gamut compared to the case of separating / modulating RGB three primary colors, the light from the light source may be separated into four colors and the four primary colors may be controlled. For example, a projector described in Patent Document 1 separates light from a light source into three primary color lights by a cross dichroic mirror, and one of the primary color lights has a polarization converter and a PBS (Polarized Beam Splitter: (Polarized beam splitter) The light is further separated into two primary color lights by a prism, so that a total of four primary color lights are separated.

  At the time of synthesis, the two primary color lights separated by the PBS prism are modulated by a reflection type light valve, and each modulated light is re-incident on the PBS prism to be synthesized. The other two primary color lights are modulated using a dichroic prism and a reflective light valve, respectively. Then, the three modulated lights are synthesized by the cross dichroic prism to create a color image in which the four primary colors are controlled.

  Non-Patent Document 1 describes a projector that performs modulation control of four primary colors using a transmissive light valve. FIG. 9 is a diagram showing a schematic configuration of a projector according to Non-Patent Document 1. As shown in FIG. 9, this projector separates blue (B) light, green (G) light, red (R) light, and yellow (Y) light in order from the light from the light source, and modulates RGB three-color modulated light. Are synthesized, and then Y color modulated light is synthesized to produce a color image.

  Here, the RGB modulated light is synthesized by the dichroic prism 300, and the RGB light and Y light are synthesized by the color selection type polarization converter 301 to convert the RGB light into a polarization direction different from that of the Y light. Synthesis is performed by the PBS prism 302.

JP-A-2005-241904 By Sammu Roth, Walt Caldwell, "Four Primary Color Projection Display", "SID Symposium Digest of Technical Papers", (Israel), May 2005, Vol. 36, No. 1, p. 1818-1821

  However, since the technique described in Patent Document 1 requires a total of four prisms including a PBS prism, a cross dichroic prism, and two dichroic prisms, the number of parts of the optical system increases and the cost increases. In addition, since the technology is based on a reflective light valve, it cannot be applied to a transmissive light valve. The technique described in Non-Patent Document 2 uses a color-selective polarization converter and a PBS prism at the time of synthesis, which increases the cost.

  As described above, with the conventional technology, it has been difficult to realize a projector having a wide color reproduction range at a low cost.

  SUMMARY An advantage of some aspects of the invention is that it provides a projector that can realize a wide color gamut at a low cost.

  The projector of the present invention that achieves the above object includes an illumination optical system, a color separation optical system that separates illumination light from the illumination optical system into a plurality of primary color lights of four colors or five colors, and a plurality of primary color lights. A plurality of spatial light modulation elements that modulate the primary color light corresponding to each, a combination optical system that combines a plurality of modulated lights modulated by the plurality of spatial light modulation elements, and a combination optical system A projection optical system for projecting the combined light by the first color combining element that combines three modulated lights of the plurality of modulated lights and an unsynthesized of the plurality of modulated lights. A second reflective surface that reflects light in the wavelength range of the modulated light, and is arranged so that the optical axes of the unsynthesized modulated light reflected by the reflective surface and the synthesized light by the first color synthesis element are aligned; And a color synthesizing element.

  According to this configuration, light modulation is performed for each primary color light separated into four colors or five colors, and three of the modulated lights are synthesized by the first color synthesis element, and further, the unsynthesized modulated light and the first color light are synthesized. The synthesized light from the color synthesizing element is synthesized by the second color synthesizing element. Here, the second color composition element reflects the unsynthesized modulated light by a reflecting surface that reflects light in the wavelength range of the unsynthesized modulated light, and the unsynthesized modulated light and the first color composition element. Since the light is synthesized by aligning the optical axis with the synthesized light, a color-selective polarization rotator is not required at the time of synthesis as described in Non-Patent Document 1, and the number of parts is reduced. Accordingly, it is possible to realize a projector having a wide color reproduction range in which four or five primary color lights are controlled at a low cost.

  In the projector according to the aspect of the invention, the first color synthesizing element synthesizes three modulated lights in adjacent wavelength ranges among the plurality of modulated lights, and the reflection surface of the second color synthesizing element It preferably has a characteristic of reflecting light on the wavelength side of unsynthesized light from the wavelength range.

  In this way, since the synthesized light by the first color synthesis element and the unsynthesized modulated light are adjacent to each other in the wavelength range, the second color synthesis means performs unsynthesized from the wavelength range of the synthesized light. It is possible to perform color synthesis using a reflecting surface having a characteristic of reflecting light on the wavelength side of light, that is, a characteristic of a high-pass filter or a low-pass filter. Since it is not necessary to use a band pass filter or a PBS prism at the time of synthesis, the cost can be further reduced.

  In the projector according to the aspect of the invention, the color separation optical system may include a first color separation element that separates light from the illumination light by the first wavelength, and illumination light after separation of the first primary color light to the second color. A second color separation element that separates according to the wavelength; and a third color separation element that separates the illumination light after separation of the second primary color light according to the third wavelength. It is preferable that the wavelength and the third wavelength are sequentially set in descending order from the long wavelength side or in ascending order from the short wavelength side.

  In this way, the first, second, and third color separation elements having the high-pass filter or low-pass filter characteristics can be separated into the four primary color lights, so that the modulation control of the four primary colors is performed at a lower cost. A projector can be realized.

  In the projector of the present invention, when the illumination optical system illuminates light emitted from the high-pressure mercury lamp, the first wavelength, the second wavelength, and the third wavelength are wavelengths from 590 nm to 610 nm, It is preferable to set the wavelength from 530 nm to 540 nm and from 480 nm to 500 nm.

  In this way, the light emitted from the high-pressure mercury lamp is separated into four primary color lights of red, green, cyan, and blue, and the four primary color lights are modulated and controlled. Obtainable.

(First embodiment)
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a projector according to the first embodiment of the present invention. The projector according to the first embodiment is a projector that performs modulation control using a transmissive light valve corresponding to each of the four primary colors (red (R), green (G), cyan (C), and blue (B)). As shown in FIG. 1, a projector 1 includes an illumination optical system 10 that illuminates a light valve 30, and a color separation optical system that separates illumination light into four primary color lights and emits each primary color light to a corresponding light valve. 20, four light valves 30R, 30G, 30C, and 30B that modulate and control each of the four primary color lights according to the image signal, and a color synthesis optical system 40 that synthesizes the modulation-controlled four colors of modulated light And a projection lens (projection optical system) 50 for projecting a color image onto a screen or the like by projecting synthetic light. In FIG. 1, the optical axis of the projector is indicated by a one-dot chain line.

  The illumination optical system 10 includes a light source device 11, a first lens array 12, a second lens array 13, a polarization conversion element 14, and a superimposing lens 15.

  The light source device 11 emits substantially parallel light by combining a high-pressure mercury lamp as a light source and a reflector. In addition, a UV filter and an IR filter (not shown) are disposed on the emission side of the light source device 11, and light in a wavelength region other than visible light (an ultraviolet region of about 400 nm or less and an infrared region of about 700 nm or more) is reduced. Lighted. As the light source of the light source device 11, a metal halide lamp, an LED (Light Emitting Diode), or the like may be used.

  The first lens array 12 and the second lens array 13 are fly-eye lenses in which a plurality of small lens-shaped cells are formed in a matrix, and the cells of the first lens array 12 and the second lens array 13 are 1 Corresponds to one-to-one. The light from the light source device 11 is partitioned for each cell of the first lens array 12, and the partial light partitioned for each cell illuminates the light valve 30 by the corresponding cell of the second lens array 13 and the superimposing lens 15. Thus, the partial light of each cell is superimposed on the light valve 30. With this so-called integrator illumination, the illumination optical system 10 illuminates the light valve 30 with substantially uniform light.

  The illumination light is converted into light (S-polarized light) whose polarization direction is substantially aligned in a direction perpendicular to the paper surface by the polarization conversion element 14 disposed between the emission side of the second lens array 13 and the superimposing lens 15. It is modulated and enters the light valve 30 in the state of S-polarized light.

  The color separation optical system 20 is for three dichroic mirrors 21, 22, 23, a mirror 24, and field lenses 25 R, 25 G, 25 C, 25 B, and C light for separating light from the illumination optical system 10 into RGCB four-color light. The first relay optical system 60 and the second relay optical system 70 for B light are provided. The first relay optical system 60 includes relay lenses 61 and 62 and a mirror 63, and the second relay optical system 70 includes relay lenses 71, 73 and 74 and mirrors 72 and 75.

  The dichroic mirrors 21, 22, and 23 are coated with a dielectric multilayer film that reflects light in a specific wavelength band on the surface of a plate-like glass member, and separates light in the red wavelength range (R light). A mirror 21, a dichroic mirror 22 for separating light in the green wavelength range (G light), a dichroic mirror 23 for separating light in the cyan wavelength range (C light) and light in the blue wavelength range (B light), and Are arranged in order from the incident side along the optical axis, and each mirror is disposed at 45 ° to the optical axis. The characteristics of 21, 22, and 23 of each dichroic mirror are set as follows according to the spectral characteristics of the high-pressure mercury lamp.

  FIG. 2A shows the spectral reflection characteristics of the dichroic mirror 21 with respect to 45 ° incident light. As shown in FIG. 2A, the dichroic mirror 21 has a characteristic of a low-pass filter that reflects light in the long wavelength region and transmits light in the short wavelength region, and has a wavelength λ1 corresponding to a reflectance of 50%. Is set to a value in the range of 590 to 610 nm. Thereby, the dichroic mirror 21 has characteristics of reflecting R light and transmitting G light, C light, and B light.

  FIG. 2B shows spectral reflection characteristics of the dichroic mirror 22 with respect to 45 ° incident light. As shown in FIG. 2B, the dichroic mirror 22 also has a low-pass filter characteristic, and the wavelength λ2 corresponding to the reflectance of 50% is set to a value in the range of 530 to 540 nm. As a result, the dichroic mirror 22 has characteristics of reflecting R and G light and transmitting C and B light.

  FIG. 2C shows spectral reflection characteristics of the dichroic mirror 23 with respect to 45 ° incident light. As shown in FIG. 2C, the dichroic mirror 23 also has the characteristics of a low-pass filter, and the wavelength λ3 corresponding to the reflectance of 50% is set to a value in the range of 480 to 500 nm. Accordingly, the dichroic mirror 23 has characteristics of reflecting R light, G light, and C light and transmitting B light.

  According to the color separation optical system 20, the illumination light from the illumination optical system 10 is first reflected by the dichroic mirror 21. The R light is further reflected toward the light valve 30 by the mirror 24, and illuminates the light valve 30R in a state of being substantially parallelized by the field lens 25R.

  On the other hand, G light, C light, and B light pass through the dichroic mirror 21 and enter the dichroic mirror 22. The dichroic mirror 22 reflects the G light toward the light valve 30G, and illuminates the light valve 30G in a state of being substantially parallelized by the field lens 25G.

  The C and B lights that have passed through the dichroic mirror 22 enter the dichroic mirror 23. The dichroic mirror 23 reflects C light and transmits B light. The reflected C light is emitted toward the light valve 30 via the first relay optical system 60, and illuminates the light valve 30C in a state of being substantially parallelized by the field lens 25C.

  The B light transmitted through the dichroic mirror 23 is irradiated toward the light valve 30 via the second relay optical system 70, and illuminates the light valve 30B in a state of being substantially parallelized by the field lens 25B.

  In this way, the color separation optical system 20 separates the illumination light from the illumination optical system 10 into R, G, C, and B light, and each of the separated lights illuminates the corresponding light valve 30.

  The light valve 30 includes a light transmission type liquid crystal panel, an incident side polarizing plate disposed on the incident side, and an outgoing side polarizing plate disposed on the outgoing side. The incident-side polarizing plate is provided so as to further increase the degree of polarization of light (S-polarized light) whose polarization direction is aligned by the polarization conversion element 14, and the light with the increased degree of polarization irradiates the liquid crystal panel. The liquid crystal panel performs modulation control of light transmitted through the liquid crystal panel in accordance with image signals for each of R, G, C, and B colors supplied from a drive unit (not shown). The modulated modulated light is emitted to the color synthesizing optical system 40 so that light in a predetermined polarization direction is absorbed by the output side polarizing plate.

  The color combining optical system 40 includes a first dichroic prism 41 that combines R modulated light, G modulated light, and C modulated light, a second dichroic prism 42 that combines B modulated light with RGC combined light, And a glass member 43 for adjusting the optical path length of the light of the relay optical system.

  The first dichroic prism 41 has mirror surfaces 41a and 41b of dielectric multilayer films that intersect each other at 90 °. Further, the G modulated light from the light valve 30 is incident on one surface of the prism, the R modulated light is incident on one side surface of the G incident surface, and the C modulated light is incident on the other side surface. The mirror surfaces 41a and 41b are arranged so as to be 45 ° with respect to the optical axis of the R modulated light, the optical axis of the G modulated light, and the optical axis of the C modulated light.

  The spectral reflection characteristics of the mirror surface 41a with respect to 45 ° incident light are shown in FIG. As shown in FIG. 3A, the mirror surface 41a has a low-pass filter characteristic, and the wavelength λ4 corresponding to the reflectance of 50% is set to a value in the range of 590 to 610 nm. As a result, the mirror surface 41a reflects R light and transmits G, C, and B light.

  FIG. 3B shows spectral reflection characteristics of the mirror surface 41b with respect to 45 ° incident light. As shown in FIG. 3B, the mirror surface 41b has the characteristics of a high-pass filter that reflects the short wavelength region and transmits the long wavelength region, and the wavelength λ5 corresponding to the reflectance of 50% is 530 to 540 nm. It is set to a value within the range. Thereby, the mirror surface 41b has a characteristic of reflecting C and B light and transmitting R and G light.

  The second dichroic prism 42 has a mirror surface 42a of a dielectric multilayer film connecting the diagonals of the prism. RGC combined light is incident on one surface of the prism, and B modulated light from the light valve 30 is incident on the side surface of the combined light incident surface, and the mirror surface 42a modulates G. They are arranged at 45 ° with respect to both the optical axis of the light and the optical axis of the modulated light of B.

  The spectral reflection characteristics of the mirror surface 42a with respect to 45 ° incident light are shown in FIG. As shown in FIG. 3C, the mirror surface 42a has a high-pass filter characteristic, and the wavelength λ6 corresponding to the reflectance of 50% is set to a value in the range of 480 to 500 nm. As a result, the mirror surface 42a reflects B light and transmits R, G, C light.

  In the color combining optical system 30, first, R, G, and C modulated light is incident on the three surfaces of the first dichroic prism 41. At this time, the modulated light of R and the modulated light of C are each shifted by 90 ° with respect to the optical axis of the modulated light of G. The R modulated light is reflected by the mirror surface 41a disposed at 45 ° with respect to the optical axis of the G modulated light, so that the G modulated light and the optical axis are aligned. The C modulated light is also reflected by the mirror surface 41b, so that the G modulated light and the optical axis are aligned. In this way, RGC synthesized light is synthesized such that the modulated light of R, C, G is aligned with the optical axis.

  RGC combined light and B modulated light are incident on the second dichroic prism 42. At this time, the B modulated light is shifted by 90 ° with respect to the optical axis of the G modulated light. The B modulated light is reflected by the mirror surface 42a disposed at 45 ° with respect to the optical axis of the G modulated light, so that the RGC synthesized light and the optical axis are aligned. In this way, the RGCB synthesized light is synthesized such that the modulated light of B is aligned with the optical axis of the synthesized light of RGC.

  The combined light of RGCB synthesized by the color synthesis optical system 40 is projected onto a screen or the like outside the projector by the projection lens 50 to display a color image.

  As described above, in the projector according to the first embodiment, the light from the light source device 11 is separated into the four primary color lights of R, G, C, and B by the dichroic mirrors 21, 22, and 23. Each time, light modulation conversion by the light valve 30 is performed. Then, after the R, G, C modulated light is synthesized by the first dichroic prism 41, the B modulated light is further synthesized by the second dichroic prism 42, thereby displaying a color image in which the four primary colors are separately controlled. .

FIG. 4 is a diagram showing an example of the color gamut obtained by the projector of the present embodiment on the xy chromaticity coordinates. The color reproduction range when the three colors of RGB are controlled is CG _3LCD , the color reproduction range of the projector of this embodiment is CG _4LCD , and the color gamut CG _NTSC of the NTSC standard. As shown in FIG. 4, the color reproduction gamut CG _3LCD at the time of three-color control is smaller than the NTSC color gamut CG _NTSC , and particularly the cyan color gamut is insufficient. On the other hand, the color reproduction range CG _4LCD at the time of four color control is wider than the color reproduction range CG _3LCD at the time of three color control, and in particular, by adding cyan to the fourth primary color, the color range in the cyan direction is expanded. As a result, the color gamut of the cyan region that is particularly insufficient compared to the NTSC color gamut during the three-color control can be compensated.

Further, since the color reproduction range is widened, the degree of freedom of adjustment such as white balance adjustment is improved. Figure 5 is a diagram showing a color gamut CG _4LCD during color gamut CG _3LCD and 4-color control at three colors control on L ^* u ^* v ^* coordinates. For example, as shown in FIG. 5, when the gray axis is set in the lightness axis direction by white balance adjustment, the white balance is _equal to the difference (ΔL) in the gray axis direction between the color reproduction area CG _3LCD and the color reproduction area CG _4LCD. The brightness after adjustment can be increased.

  Hereinafter, effects in the present embodiment will be described.

  (1) By individually modulating and controlling each color light of RGCB, it is possible to obtain a projector having a wider color reproduction range compared to the case of three-color control. In addition, since the color reproduction range is widened, the degree of freedom in color adjustment is improved, and the brightness that can be reproduced after white balance adjustment is improved.

  (2) Since the RGC three-color combined light and the fourth color B-modulated light are combined by the second dichroic prism 42, the PBS prism and the polarization conversion element are provided on the incident side of the PBS prism as shown in Non-Patent Document 1. There is no need. Accordingly, it is possible to obtain a projector having a wide color reproduction range at a lower cost.

  (3) The dichroic mirrors 21, 22, and 23 having the characteristics of a low-pass filter color-separated the RGCB light from the light source device 11 into R light, G light, C light, and B light in order from the long wavelength side. By using a low-pass filter that is lower in cost than a band-pass filter, color separation can be performed at a lower cost.

  (4) Of the R, G, C, and B lights separated in order from the long wavelength side, three modulated lights (R light, G light, and C light) on the long wavelength side are synthesized by the first dichroic prism 41, and further, Since the synthesized modulated light (B light) is synthesized by the second dichroic prism 42 having the characteristics of a high-pass filter, color synthesis can be performed at low cost.

  (5) By using cyan as the fourth primary color in addition to RGB, it is possible to effectively compensate for the insufficient color gamut with respect to the NTSC color gamut.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. The second embodiment is a projector that uses yellow (Y) as the fourth primary color in addition to the three primary colors RGB.

  As shown in FIG. 6, the projector 100 according to the second embodiment includes an illumination optical system 10, a color separation optical system 120, light valves 30R, 30Y, 30G, and 30B, a color synthesis optical system 140, and a projection. And a projection lens 50 as an optical system. Note that the illumination optical system 10 and the projection lens 50 have the same configuration as that of the projector 1 according to the first embodiment.

  The dichroic mirror of the color separation optical system 120 includes a dichroic mirror 26 for separating R light, a dichroic mirror 27 for separating Y (yellow) light, and a dichroic mirror 28 for separating G light and B light along the optical axis. The mirrors are arranged in order from the incident side, and each mirror is disposed at 45 ° to the optical axis. The characteristics of the dichroic mirrors 26, 27, and 28 correspond to the spectral characteristics of the light emitted from the high-pressure mercury lamp. The dichroic mirror 28 is set to have a low-pass filter characteristic of 480 nm to 500 nm. Thereby, the color separation optical system 120 separates the light from the light source device 11 into R light, Y light, G light, and B light.

  The Y modulated light, the G modulated light, and the B modulated light are combined by the first dichroic prism 141 of the combining optical system 140, and the R modulated light is combined by the second dichroic prism 142.

  In this way, by adding Y light as the fourth primary color to the three colors of RGB, it is possible to obtain a projector in which the yellow color reproduction range is expanded.

(Third embodiment)
Next, a third embodiment of the present invention will be described. The third embodiment is a projector that uses five primary colors (R light, Y light, G light, C light, and B light).

  As shown in FIG. 7, the projector 200 according to the third embodiment includes an illumination optical system 10, a color separation optical system 220, light valves 30R, 30Y, 30G, 30C, and 30B, and a color synthesis optical system 240. And a projection lens 50 as a projection optical system. Note that the illumination optical system 10 and the projection lens 50 have the same configuration as that of the projector 1 according to the first embodiment.

  The color separation optical system 220 includes a dichroic mirror 26 that reflects R light, a dichroic mirror 27 that reflects Y light, a dichroic mirror 22 that reflects G light, and a dichroic mirror 23 that reflects C light. Separate the light into five primary colors.

  The color combining optical system 240 combines Y modulated light, G modulated light, and C modulated light by the first dichroic prism 241, and YGC combined light, R modulated light, and B modulated light by the second dichroic prism 242. Combines with modulated light.

  In this way, it is possible to obtain a projector having a wide color reproduction range by modulating and controlling the five primary colors.

  The first to third embodiments of the present invention have been described above. However, the present invention is not limited to this, and various forms can be adopted. Hereinafter, modifications of the present invention will be described.

  (Modification 1) In the first and second embodiments, light is separated in order from the long wavelength side, but B light, C light, G light, R light or B light, G light are sequentially arranged from the short wavelength side. , Y light, R light may be separated in this order.

  (Modification 2) When the four primary colors of R light, G light, C light, and B light are separated, the first dichroic prism 41 combines the G modulated light, the C modulated light, and the B modulated light. R modulated light may be synthesized by a two-dichroic prism. In addition, when the four primary colors of R light, Y light, G light, and B light are separated, the first dichroic prism 41 combines the R modulated light, Y modulated light, and G modulated light, and then the second dichroic prism. 42 may synthesize B modulated light.

  (Modification 3) A dichroic mirror may be used instead of the dichroic prism. That is, instead of the first dichroic prism 41, two dichroic mirrors arranged in an X shape at 45 ° with respect to the optical axis, or instead of the second dichroic prism 42, arranged at 45 ° with respect to the optical axis. You may synthesize | combine by a dichroic mirror.

  (Modification 4) In the above embodiment, since there is no need to provide a color selective polarization conversion element on the emission side of the first dichroic prism 41 as in the technique described in Non-Patent Document 1, the first dichroic prism 41 and the first dichroic prism 41 The two-dichroic prism 42 can be integrated. As shown in FIG. 8, if the synthetic light emission surface of the first dichroic prism 41 is joined to the synthetic light incidence surface of the second dichroic prism 42, the positioning accuracy between the prisms can be easily increased. Can achieve lower cost.

  (Modification 5) The present invention is not limited to a front projection projector, but can be applied to a rear projector.

1 is a configuration diagram showing a schematic configuration of a projector according to a first embodiment. The figure which showed the spectral reflection characteristic of the color separation optical system, (a)-(c) is the figure which showed the spectral reflection characteristic of each dichroic mirror. The figure which showed the spectral reflection characteristic of the synthetic | combination optical system, (a)-(c) was the figure which showed the spectral reflection characteristic of each mirror surface. The figure which showed the color reproduction area at the time of 3 primary color control and 4 primary color control by xy coordinate. The figure which showed the color reproduction area at the time of 3 primary color control and 4 primary color control by the L ^* u ^* v ^* coordinate. The block diagram which showed schematic structure of the projector which concerns on 2nd Embodiment. The block diagram which showed schematic structure of the projector which concerns on 3rd Embodiment. Explanatory drawing explaining a 4th modification. The block diagram which showed schematic structure of the conventional projector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Projector, 10 ... Illumination optical system, 11 ... Light source device, 12 ... 1st lens array, 13 ... 2nd lens array, 14 ... Polarization conversion element, 15 ... Superimposing lens, 20 ... Color separation optical system, 21 ... 1st Dichroic mirror as one color separation element, 22 ... Dichroic mirror as a second color separation element, 23 ... Dichroic mirror as a third color separation element, 24 ... Mirror, 25 ... Field lens, 30 ... Spatial light modulation element Light valve, 40 ... color synthesis optical system, 41 ... first dichroic prism as first color synthesis element, 41a ... mirror surface, 41b ... mirror surface, 42 ... second dichroic prism as second color synthesis element, 42a ... Mirror surface as reflection surface, 43 ... Glass member for adjusting optical path length, 50 ... Projection lens as projection optical system, 60 ... No. The relay optical system, 70 ... second relay optical system, 100 ... projector according to the second embodiment, the color gamut of the CG _3LCD ... 3 primary color display when color gamut when CG _4LCD ... 4-primary-color display, CG _NTSC : NTSC color gamut, λ1: wavelength as the first wavelength, λ2: wavelength as the second wavelength, λ3: wavelength as the third wavelength.

Claims (4)

Illumination optics,
A color separation optical system for separating the illumination light from the illumination optical system into a plurality of primary color lights of four colors or five colors;
A plurality of spatial light modulators provided corresponding to each of the plurality of primary color lights, each of which modulates and controls the corresponding primary color light;
A combining optical system for combining a plurality of modulated lights modulated by the plurality of spatial light modulation elements;
A projection optical system for projecting synthesized light from the synthesis optical system,
The synthetic optical system is
A first color synthesizing element that synthesizes three of the plurality of modulated lights;
A reflection surface that reflects light in a wavelength range of the unsynthesized modulated light out of the plurality of modulated lights, and the unsynthesized modulated light reflected by the reflection surface and the synthesized light by the first color synthesis element; And a second color composition element arranged so that their optical axes are aligned. The projector according to claim 1, wherein
The first color synthesis element synthesizes three modulated lights in adjacent wavelength ranges among the plurality of modulated lights,
The projector according to claim 1, wherein the reflection surface of the second color synthesis element has a characteristic of reflecting light on a wavelength side of the unsynthesized light from a wavelength range of the synthesized light. The projector according to claim 2,
The color separation optical system is
A first color separation element that separates light from the illumination light by a first wavelength;
A second color separation element for separating the illumination light after separation of the first primary color light by a second wavelength;
A third color separation element for separating the illumination light after separation of the second primary color light by a third wavelength;
The projector according to claim 1, wherein the first wavelength, the second wavelength, and the third wavelength are sequentially set in descending order from the long wavelength side or in ascending order from the short wavelength side. The projector according to claim 3, wherein
When the illumination optical system illuminates light emitted from a high-pressure mercury lamp,
The first wavelength, the second wavelength, and the third wavelength are:
A projector having a wavelength of 590 nm to 610 nm, a wavelength of 530 nm to 540 nm, and a wavelength of 480 nm to 500 nm.

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