Projection type display apparatus

Abstract

To provide a projection type display apparatus capable of suppressing an increase in an optical system.SOLUTION: A projection type display apparatus comprises: a first electro-optical device that emits first image light of a first color; a second electro-optical device that emits second image light of a second color and a second polarization; a third electro-optical device that emits third image light of a third color and a first polarization; a fourth electro-optical device that emits fourth image light of the third color and the second polarization; and a first cross dichroic prism that synthesizes the first image light and the third image light, a second cross dichroic prism that synthesizes and emits the first synthesized light emitted from the first cross dichroic prism, the second image light and the fourth image light, and a first prism and a second prism which are arranged in the second cross dichroic prism. The first electro-optical device is disposed on a first incidence surface of the first cross dichroic prism, and the third electro-optical device is disposed on a second incidence surface so as to face the first electro-optical device. The second electro-optical device is disposed to face an incidence surface of the first prism, and the fourth electro-optical device is disposed to face an incidence surface of the second prism.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a projection display device. [Background technology]

[0002] It has been disclosed that in a projector, which is a projection display device, two blue liquid crystal panels are used, and S-polarized light and P-polarized light are respectively incident on a combining prism to be combined with red and green light, and then image light is projected, thereby improving the lifespan and reliability (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 104000 Summary of the Invention [Problem to be solved by the invention]

[0004] In the projection display device of Patent Document 1, the lifespan of the liquid crystal panel can be extended by separating the blue liquid crystal panel into S-polarized and P-polarized light and directing each to a separate liquid crystal panel, but there is a problem in that the optical system becomes large because the cross prism, prism, and reflective mirror are arranged horizontally on the four panels. [Means for solving the problem]

[0005] In order to achieve the above object, according to one aspect of the present invention, there is provided a first electro-optical device that emits first image light of a first color and a first polarization, a second electro-optical device that emits second image light of a second color different from the first color and a second polarization different from the first polarization, a third electro-optical device that emits third image light of a third color different from the first color and the second color and the first polarization, a fourth electro-optical device that emits fourth image light of the third color and the second polarization, a first cross dichroic prism that combines the first image light and the third image light and emits the combined light, a second cross dichroic prism that combines the first combined light, the second image light, and the fourth image light emitted from the first cross dichroic prism, and an electro-optical element disposed on a side of the second cross dichroic prism along a first direction as viewed from an exit surface of the second cross dichroic prism. and a synthetic optical system having a first prism arranged on a surface of the second cross dichroic prism opposite to the surface on which the first prism is arranged, the first electro-optical device being arranged along the first direction when viewed from the exit surface of the second cross dichroic prism and facing the first entrance surface of the first cross dichroic prism, the third electro-optical device being arranged along the first direction when viewed from the exit surface of the second cross dichroic prism and facing the second entrance surface of the first cross dichroic prism, and facing the first electro-optical device across the first cross dichroic prism, the second electro-optical device being arranged facing the entrance surface of the first prism, and the fourth electro-optical device being arranged facing the entrance surface of the second prism. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a projector which is a projection-type display device according to a first embodiment. [Figure 2] FIG. 3 is a cross-sectional view of a part of the projector viewed in the width direction. [Figure 3] A top view of part of the projector. [Figure 4]FIG. 3 is a cross-sectional view of a part of the projector viewed in the width direction. [Figure 5] FIG. 10 is a diagram showing a first pattern of S-polarized light specialized characteristics. [Figure 6] FIG. 10 is a diagram showing a second pattern of S-polarized light specialized characteristics. [Figure 7] FIG. 10 is a diagram showing a schematic configuration of a projector that is a projection-type display device according to a second embodiment. [Figure 8] FIG. 3 is a cross-sectional view of a part of the projector viewed in the width direction. [Figure 9] FIG. 10 is a diagram showing a first pattern of S-polarized light specialized characteristics. [Figure 10] FIG. 10 is a diagram showing a second pattern of S-polarized light specialized characteristics. [Figure 11] FIG. 10 is a top view of a second embodiment of the substrate. [Figure 12] FIG. 4 is a cross-sectional view of a second embodiment of the substrate as viewed in the width direction. [Figure 13] FIG. 10 is a top view of a third embodiment of the substrate. [Figure 14] FIG. 10 is a cross-sectional view of a third embodiment of the substrate as viewed in the width direction. [Figure 15] FIG. 10 is a top view of a fifth embodiment of the substrate. [Figure 16] FIG. 10 is a cross-sectional view of a fifth embodiment of the substrate as viewed in the width direction. [Figure 17] FIG. 10 is a top view of a sixth embodiment of the substrate. [Figure 18] FIG. 10 is a cross-sectional view of a sixth embodiment of the substrate as viewed in the width direction. [Figure 19] FIG. 10 is a top view of a seventh embodiment of the substrate. [Figure 20] FIG. 10 is a cross-sectional view of a seventh embodiment of the substrate as viewed in the width direction. [Figure 21] FIG. 13 is a top view of a ninth embodiment of the substrate. [Figure 22] FIG. 13 is a cross-sectional view of a ninth embodiment of the substrate as viewed in the width direction. [Figure 23] FIG. 11 is a top view of an eleventh embodiment of the substrate. [Figure 24] FIG. 16 is a cross-sectional view of an eleventh embodiment of the substrate as viewed in the width direction. [Figure 25] FIG. 13 is a top view of a thirteenth embodiment of the substrate. [Figure 26]FIG. 13 is a cross-sectional view of the thirteenth embodiment of the substrate viewed in the width direction. [Figure 27] FIG. 15 is a top view of the fifteenth embodiment of the substrate. [Figure 28] FIG. 15 is a cross-sectional view of the fifteenth embodiment of the substrate viewed in the width direction. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, an embodiment of a projection display device of the present invention will be described with reference to FIGS. The following embodiment shows one aspect of the present invention, does not limit the present invention, and can be modified as desired within the scope of the technical concept of the present invention. In addition, in the following drawings, the scale and number of each structure are different from the actual structure to make each configuration easier to understand.

[0008] [First embodiment of projection display device] Fig. 1 is a schematic configuration diagram of a projector 1, which is a projection display device according to a first embodiment, viewed from above. Fig. 2 is a cross-sectional view of a portion of the projector 1 viewed in the width direction. In Fig. 2, the screen SCR, light source device 2, and projection optical device 6 are not shown.

[0009] 1 and 2, a projector 1, which is an example of a projection display device, is a projection display device that displays a color image on a screen SCR. The projector 1 includes a light source device 2, a color separation optical system 3, a projection optical device 6, a combining optical system 10, a first electro-optical device P1, a second electro-optical device P2, a third electro-optical device P3, and a fourth electro-optical device P4.

[0010] The following explanation will be given using a three-dimensional coordinate system of X, Y, and Z. The Z direction is the up-down direction. The Y direction is a direction perpendicular to the Z direction, and is the direction in which the projector 1 projects image light onto the screen SCR. The X direction is a direction perpendicular to the Z direction and the Y direction. The Y direction corresponds to the first direction. The X direction corresponds to the width direction.

[0011] The color separation optical system 3 separates the white illumination light WL emitted from the light source device 2 into green light LG, red light LR, blue light LB1, and blue light LB2. The color separation optical system 3 includes dichroic mirrors 7a and 7b, total reflection mirrors 8a, 8b, 8c, 8d, and 8e, and a half mirror 9a.

[0012] The dichroic mirror 7a separates the illumination light WL from the light source device 2 into red light LR and cyan light LC. The dichroic mirror 7a transmits the red light LR and reflects the cyan light LC. The red light LR separated after passing through the dichroic mirror 7a is guided to the second electro-optical device P2 as a second polarized light different from the first polarized light via a polarizing plate (not shown). The cyan light LC separated after being reflected by the dichroic mirror 7a is guided to the dichroic mirror 7b.

[0013] Dichroic mirror 7b separates the cyan light LC from dichroic mirror 7a into green light LG and blue light LB. Dichroic mirror 7b reflects the green light LG and transmits the blue light LB. The green light LG that has been reflected and separated by dichroic mirror 7b is guided to total reflection mirror 8a.

[0014] 2, total reflection mirror 8a reflects green light LG toward total reflection mirror 8b. Total reflection mirror 8b is disposed above total reflection mirror 8a (on the +Z side). The green light LG reflected by total reflection mirror 8a and directed upward is then reflected by total reflection mirror 8b and guided with the first polarization to first electro-optical device P1 via a polarizer (not shown) and a first wire-grid polarizer WG1 (described later).

[0015] The blue light LB separated after passing through the dichroic mirror 7b is reflected by a total reflection mirror 8c and directed to a half mirror 9a. The half mirror 9a transmits a portion (e.g., half) of the blue light LB and reflects at least a portion (e.g., the remaining half) of the remaining blue light LB toward a total reflection mirror 8d. The blue light LB transmitted through the half mirror 9a is directed as blue light LB2 with the second polarization via a polarizing plate (not shown) to the fourth electro-optical device P4.

[0016] The blue light LB reflected by the half mirror 9a is guided to the total reflection mirror 8d as blue light LB1. The total reflection mirror 8d is arranged on the +X side of the half mirror 9a. The total reflection mirror 8d reflects the blue light LB1 toward the total reflection mirror 8e, which is arranged below (on the -Z side of) the total reflection mirror 8d. The blue light LB1 reflected by the total reflection mirror 8d and heading downward is reflected by the total reflection mirror 8e and guided as the first polarization to the third electro-optical device P3 via a polarizer (not shown) and a second wire-grid polarizer WG2 (described later).

[0017] The first electro-optical device P1 is a liquid crystal device that modulates green light LG according to image information to form and emit first image light of a first color, which is green and has a first polarization. Hereinafter, the first image light will be referred to as green light LG. The second electro-optical device P2 is a liquid crystal device that modulates red light LR according to image information to form and emit second image light of a second color, which is red and has a second polarization, different from the first color. Hereinafter, the second image light will be referred to as red light LR. The third electro-optical device P3 is a liquid crystal device that modulates blue light LB1 according to image information to form and emit third image light of a third color, which is blue and has a first polarization, different from the first and second color lights. Hereinafter, the third image light will be referred to as blue light LB1. The fourth electro-optical device P4 is a liquid crystal device that modulates blue light LB2 according to image information to form and emit fourth image light of a third color, which is blue and has a second polarization, different from the first polarization of blue. Hereinafter, the fourth image light will be referred to as blue light LB2. The first polarized light is, for example, P polarized light. The second polarized light is, for example, S polarized light.

[0018] The first electro-optical device P1 is disposed opposite a first entrance surface 4C of the first cross dichroic prism 4, which will be described later. The first entrance surface 4C is the surface facing the +Z side of the first cross dichroic prism 4. When viewed from the exit surface of the second cross dichroic prism 5, the first electro-optical device P1 is disposed along the Y direction, which is the first direction.

[0019] The third electro-optical device P3 is disposed opposite the second entrance surface 4D of the first cross dichroic prism 4. The second entrance surface 4D is the surface of the first cross dichroic prism 4 facing the -Z side. The third electro-optical device P3 is disposed along the Y direction when viewed from the exit surface of the second cross dichroic prism 5. In other words, the first electro-optical device P1 and the third electro-optical device P3 are disposed opposite each other in the Z direction with the first cross dichroic prism 4 sandwiched between them.

[0020] The second electro-optical device P2 is disposed opposite to an incident surface 11a of a first prism 11, which will be described later. The incident surface 11a is the surface of the first prism 11 that faces the -Y side. The fourth electro-optical device P4 is disposed opposite to an incident surface 12a of a second prism 12, which will be described later. The incident surface 12a is the surface of the second prism 12 that faces the -Y side.

[0021] Fig. 3 is a diagram showing a part of the projector 1 as viewed from above. Fig. 4 is a cross-sectional view showing a part of the projector as viewed in the width direction (X direction). 3 and 4, the first electro-optical device P1 has a substrate K1. The second electro-optical device P2 has a substrate K2. The third electro-optical device P3 has a substrate K3. The fourth electro-optical device P4 has a substrate K4.

[0022] The substrates K1, K2, K3, and K4 transmit signals related to the formation of image light to the first electro-optical device P1, the second electro-optical device P2, the third electro-optical device P3, and the fourth electro-optical device P4, respectively. The substrates K1, K2, K3, and K4 are, for example, flexible FPC (Flexible Printed Circuits) substrates or COF (Chip on Film) substrates.

[0023] The substrates K1 and K3 extend toward the +Y side from the +Y-side ends of the first electro-optical device P1 and the third electro-optical device P3. The substrates K2 and K4 extend toward the +Z side from the +Z-side ends of the second electro-optical device P2 and the fourth electro-optical device P4. In the following description, when a substrate extends upward in a view from above, it is indicated by an L-shaped arrow with its tip pointing upward, and when a substrate extends downward, it is indicated by an L-shaped arrow with its tip pointing downward.

[0024] 3 and 4 all extend in a direction away from the color separation optical system 3. By having the substrates K1, K2, K3, and K4 all extend in a direction away from the color separation optical system 3, it is possible to suppress interference with the optical path of light in the color separation optical system 3 and to suppress adverse effects on the optical path caused by heat generated by the substrates K1, K2, K3, and K4. Furthermore, gaps are provided around the first prism 11, second prism 12, and first cross dichroic prism 4 on which the substrates K1, K2, K3, and K4 are disposed, providing air flow paths, which allows for smooth cooling.

[0025] The combining optical system 10 includes a first cross dichroic prism 4, a second cross dichroic prism 5, a first wire grid polarizer WG1, a second wire grid polarizer WG2, a first prism 11, and a second prism 12.

[0026] The first wire-grid polarizer WG1 is disposed on the +Y side of the total reflection mirror 8b. The first wire-grid polarizer WG1 is disposed on the +Z side of the first cross dichroic prism 4. The first wire-grid polarizer WG1 is disposed opposite the first entrance surface 4C of the first cross dichroic prism 4 and the +Z side of the first electro-optical device P1. The first wire-grid polarizer WG1 reflects the green light LG from the total reflection mirror 8b and guides it to the first cross dichroic prism 4 via the first electro-optical device P1. The green light LG reflected by the first wire-grid polarizer WG1 is guided to the first cross dichroic prism 4 as S-polarized light.

[0027] The second wire-grid polarizer WG2 is disposed on the +Y side of the total reflection mirror 8e. The second wire-grid polarizer WG2 is disposed on the -Z side of the first cross dichroic prism 4. The second wire-grid polarizer WG2 is disposed opposite the second entrance surface 4D of the first cross dichroic prism 4 and the -Z side of the third electro-optical device P3. The second wire-grid polarizer WG2 reflects the blue light LB1 from the total reflection mirror 8e and guides it to the first cross dichroic prism 4 via the third electro-optical device P3. The blue light LB1 reflected by the second wire-grid polarizer WG2 is guided to the first cross dichroic prism 4 as S-polarized light.

[0028] The first cross dichroic prism 4 combines the incident green light LG and blue light LB1 and outputs the combined light to the second cross dichroic prism 5. The first cross dichroic prism 4 has a first dichroic surface 4A and a second dichroic surface 4B. The first dichroic surface 4A is a surface that slopes in a direction toward the +Y side as it approaches the -Z side. The second dichroic surface 4B is a surface that slopes in a direction toward the +Y side as it approaches the +Z side.

[0029] To combine the incident green light LG and blue light LB1, the first dichroic surface 4A and the second dichroic surface 4B have two patterns of S-polarized light specialization characteristics. FIG. 5 shows a first pattern of S-polarized light specialization characteristics for white display. As shown in FIG. 5, in the first pattern, the first dichroic surface 4A transmits blue light and reflects green and red light. In the first pattern, the second dichroic surface 4B transmits green and red light and reflects blue light.

[0030] 6 shows a second pattern of S-polarized light specialization characteristics for white display. As shown in FIG. 6, in the second pattern, first dichroic surface 4A transmits blue and red light and reflects green light. In the second pattern, second dichroic surface 4B transmits green light and reflects blue and red light.

[0031] In both the first and second patterns, green light LG incident on the first cross dichroic prism 4 is transmitted through the second dichroic surface 4B, reflected by the first dichroic surface 4A, and emitted to the second cross dichroic prism 5. Also, blue light LB1 incident on the first cross dichroic prism 4 is transmitted through the first dichroic surface 4A, reflected by the second dichroic surface 4B, and emitted to the second cross dichroic prism 5.

[0032] Therefore, the green light LG and the blue light LB1 incident on the first cross dichroic prism 4 are combined and emitted to the second cross dichroic prism 5 as a first combined light.

[0033] The first prism 11 is disposed on the +Y side of the second electro-optical device P2. When viewed from the exit surface of the second cross dichroic prism 5, the first prism 11 is disposed on a side surface of the second cross dichroic prism facing the +X side along the Y direction. The first prism 11 is a right-angle prism. The first prism 11 guides the red light LR emitted from the second electro-optical device P2 to the second cross dichroic prism 5.

[0034] The second prism 12 is disposed on the +Y side of the fourth electro-optical device P4. When viewed from the exit surface of the second cross dichroic prism 5, the second prism 12 is disposed on a side of the second cross dichroic prism facing the -X side along the Y direction. The second prism 12 is a right-angle prism. The second prism 12 guides the blue light LB2 emitted from the fourth electro-optical device P4 to the second cross dichroic prism 5.

[0035] The second cross dichroic prism 5 combines and emits the first combined light, red light LR, and blue light LB2 emitted from the first cross dichroic prism 4. The optical path lengths of the green light LG and blue light LB1 constituting the first combined light to the second cross dichroic prism 5, the optical path lengths of the red light LR incident via the first prism 11 to the second cross dichroic prism 5, and the optical path lengths of the blue light LB2 incident via the second prism 12 to the second cross dichroic prism 5 are all approximately the same, allowing the back focus to be aligned.

[0036] As described above, the projection display device of this embodiment has a third electro-optical device P3 that emits blue light LB1 and a fourth electro-optical device P4 that emits blue light LB2, and combines and emits blue light LB1 and blue light LB2. Therefore, by halving the light density of the third electro-optical device P3 and the fourth electro-optical device P4, the light resistance life can be doubled, and life reliability can be improved.

[0037] Furthermore, in the projection display device of this embodiment, the first electro-optical device P1 and the third electro-optical device P3 are arranged opposite the first entrance surface 4C and the second entrance surface 4D of the first cross dichroic prism 4 in the Z direction, and the second electro-optical device P2 and the fourth electro-optical device P4 are arranged opposite the entrance surface 11a of the first prism 11 and the entrance surface 12a of the second prism 12 in the Y direction, thereby reducing the dimension in the X direction and preventing the optical system from becoming too large.

[0038] In particular, in the projection display device of this embodiment, the color separation optical system 3 is all positioned on the -Y side of the first electro-optical device P1, the second electro-optical device P2, the third electro-optical device P3, the fourth electro-optical device P4, and the synthesis optical system 10, so the dimension in the X direction is smaller, further preventing the optical system from becoming larger.

[0039] Furthermore, in the projection display device of this embodiment, the substrates K1, K2, K3, and K4, through which signals related to the formation of image light are transmitted to the first electro-optical device P1, the second electro-optical device P2, the third electro-optical device P3, and the fourth electro-optical device P4, respectively, extend in a direction away from the color separation optical system 3, thereby preventing adverse effects caused by heat generation from the substrates K1, K2, K3, and K4 from affecting the optical path of light in the color separation optical system 3.

[0040] [Second embodiment of projection display device] Next, a second embodiment of the projector 1, which is a projection display device, will be described with reference to FIGS. In these figures, the same elements as those in the first embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals, and the description thereof will be omitted.

[0041] In the first embodiment, a configuration in which the second color is red and the third color is blue is exemplified, but in this embodiment, a configuration in which the second color is blue and the third color is red will be described.

[0042] In this embodiment, the second electro-optical device P2 modulates the blue light LB in accordance with image information to form and emit second image light of a second polarization different from the first polarization of blue light. Hereinafter, the second image light will be referred to as blue light LB.

[0043] The third electro-optical device P3 modulates the red light LR1 in accordance with image information to form and emit third image light of a third color different from the first and second color lights and of a first red polarization. Hereinafter, the third image light will be referred to as red light LR1. The fourth electro-optical device P4 modulates the red light LR2 in accordance with image information to form and emit fourth image light of a third color different from the first and second color lights and of a second polarization different from the first red polarization. Hereinafter, the fourth image light will be referred to as red light LR2.

[0044] Fig. 7 is a schematic configuration diagram of a projector 1, which is a projection display device according to the second embodiment, viewed from above. Fig. 8 is a cross-sectional view of part of the projector 1 viewed in the width direction. As shown in Fig. 7, light source device 2 has laser light sources 2G, 2B, and 2R. Laser light source 2G emits green laser light WG to the +Y side as green light LG. As shown in Fig. 8, laser light source 2G is disposed on the -Y side of first wire-grid polarizer WG1, and causes green light LG to enter first electro-optical device P1 via first wire-grid polarizer WG1.

[0045] The laser light source 2B emits blue laser light WB to the +Y side as blue light LB. The laser light source 2B is disposed on the -Y side of the second electro-optical device P2, and causes the blue light LB to enter the second electro-optical device P2. The laser light source 2R emits red laser light WR to the +Y side as red light LR. The laser light source 2R is disposed on the -Y side of the fourth electro-optical device P4.

[0046] The color separation optical system 3 has a half mirror 9b, a total reflection mirror 8f, and a total reflection mirror 8g. The half mirror 9b is disposed on the optical path of the red light LR between the fourth electro-optical device P4 and the laser light source 2R. The half mirror 9b transmits a portion (e.g., half) of the red light LR and reflects at least a portion (e.g., the remaining half) of the red light LR toward the total reflection mirror 8f. The red light LR transmitted through the half mirror 9b is guided as red light LR2 to the fourth electro-optical device P4 with the second polarization via a polarizing plate (not shown).

[0047] The red light LR reflected by the half mirror 9b is guided to the total reflection mirror 8f as red light LR1. The total reflection mirror 8f is disposed on the -X side of the half mirror 9b. The total reflection mirror 8f reflects the red light LR1 toward the total reflection mirror 8g. The total reflection mirror 8g is disposed below (on the -Z side of) the total reflection mirror 8f and on the -Y side of the second wire-grid polarizer WG2. The red light LR1 reflected by the total reflection mirror 8f and directed downward is reflected by the total reflection mirror 8g and guided to the third electro-optical device P3 as the first polarization via a polarizer (not shown) and the second wire-grid polarizer WG2.

[0048] The green light LG emitted from the first electro-optical device P1 is reflected by the first wire-grid polarizer WG1 and guided as S-polarized light to the first cross dichroic prism 4. The red light LR1 emitted from the third electro-optical device P3 is guided as S-polarized light to the first cross dichroic prism 4. The first cross dichroic prism 4 combines the incident green light LG and red light LR1 and outputs the combined light to the second cross dichroic prism 5.

[0049] To combine the incident green light LG and red light LR1, the first dichroic surface 4A and the second dichroic surface 4B have two possible S-polarized light specialization patterns. FIG. 9 shows a first pattern of S-polarized light specialization characteristics for white display. As shown in FIG. 9, in the first pattern, the first dichroic surface 4A transmits red light and reflects green and blue light. In the first pattern, the second dichroic surface 4B transmits green and blue light and reflects red light.

[0050] 10 is a diagram showing a second pattern of S-polarized light specialization characteristics for white display. As shown in FIG. 10, in the second pattern, first dichroic surface 4A transmits blue and red light and reflects green light. In the second pattern, second dichroic surface 4B transmits green light and reflects blue and red light.

[0051] In both the first and second patterns, green light LG incident on the first cross dichroic prism 4 is transmitted through the second dichroic surface 4B, reflected by the first dichroic surface 4A, and emitted to the second cross dichroic prism 5. Also, red light LR1 incident on the first cross dichroic prism 4 is transmitted through the first dichroic surface 4A, reflected by the second dichroic surface 4B, and emitted to the second cross dichroic prism 5.

[0052] Therefore, the green light LG and the red light LR1 incident on the first cross dichroic prism 4 are combined and emitted to the second cross dichroic prism 5 as a first combined light.

[0053] The second cross dichroic prism 5 combines and emits the first combined light, red light LR2, and blue light LB emitted from the first cross dichroic prism 4. The optical path lengths of the green light LG and red light LR1 constituting the first combined light to the second cross dichroic prism 5, the optical path lengths of the red light LR2 incident via the first prism 11 to the second cross dichroic prism 5, and the optical path lengths of the blue light LB incident via the second prism 12 to the second cross dichroic prism 5 are all approximately the same, allowing the back focus to be aligned.

[0054] In this embodiment, a laser light source 2R is provided that emits red laser light WR. However, the wavelength band of the laser light WR is shifted toward the longer wavelength side relative to the red wavelength band separated from the lamp light source and phosphor. In this case, the light cannot be linearly polarized by the liquid crystal and instead exhibits elliptically polarized light, which may reduce the liquid crystal conversion efficiency and result in a dark image. Therefore, while it may be possible to increase the output of the laser light source 2R, this would result in a problem of excessive temperature rise in the electro-optical device.

[0055] In this embodiment, there is a third electro-optical device P3 that emits red light LR1 and a fourth electro-optical device P4 that emits red light LR2, and the red light LR1 and red light LR2 are combined and emitted, so by halving the light density of the third electro-optical device P3 and the fourth electro-optical device P4, it is possible to suppress the temperature rise of the third electro-optical device P3 and the fourth electro-optical device P4.

[0056] Furthermore, in the projection display device of this embodiment, the first electro-optical device P1 and the third electro-optical device P3 are arranged opposite the first entrance surface 4C and the second entrance surface 4D of the first cross dichroic prism 4 in the Z direction, and the second electro-optical device P2 and the fourth electro-optical device P4 are arranged opposite the entrance surface 12a of the second prism 12 and the entrance surface 11a of the first prism 11 in the Y direction, thereby reducing the dimension in the X direction and preventing the optical system from becoming too large.

[0057] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0058] For example, in the above embodiment, a configuration that emits white illumination light WL and a configuration that includes laser light source 2G, laser light source 2B, and laser light source 2R are exemplified as light source device 2, but the present invention is not limited to this configuration. For example, a configuration may be used in which laser light source 2B is used, blue laser light WB is irradiated onto a phosphor to emit yellow light, and the emitted yellow light is separated into red light and green light by a dichroic mirror.

[0059] Furthermore, in the above embodiment, the first electro-optical device P1, the second electro-optical device P2, the third electro-optical device P3 and the fourth electro-optical device P4 are liquid crystal devices that modulate light from a light source device in accordance with image information to form image light, but this configuration is not limited to this, and each may also be configured to have a self-emitting panel. Examples of self-luminous panels include organic EL (electroluminescence) panels that use organic EL elements, which are self-luminous elements, as pixels, plasma display panels, and surface-conduction electron-emitting element panels that utilize the phenomenon of electron emission caused by passing a current parallel to the film surface through a small thin film formed on a substrate.

[0060] In the above embodiment, the light incident on the second electro-optical device P2 is converted to the second polarized light by a polarizing plate (not shown), but the present invention is not limited to this configuration and may be converted to the first polarized light. When the light is converted to the first polarized light, the transmittance characteristics of the two dichroic surfaces of the second cross dichroic prism for the second image light may be the same as those for the first polarized light.

[0061] In the above embodiment, the first mode of the substrates K1, K2, K3, and K4 is illustrated as a configuration in which the substrates K1 and K3 extend toward the +Y side and the substrates K2 and K4 extend toward the +Z side. However, the present invention is not limited to this configuration. For example, a second mode may be a configuration in which the substrates K1 and K3 extend toward the +Y side and the substrates K2 and K4 extend toward the -Z side to move away from the color separation optical system 3, as shown in Figures 11 and 12. A third mode may be a configuration in which the substrates K1 and K3 extend toward the +Y side, the substrate K2 extends toward the +Z side, and the substrate K4 extends toward the -Z side to move away from the color separation optical system 3, as shown in Figures 13 and 14. Note that, although not shown, a fourth mode may be a configuration in which the substrate K2 in the third mode extends toward the -Z side and the substrate K4 extends toward the +Z side to move away from the color separation optical system 3.

[0062] Furthermore, as a fifth aspect, as shown in Figures 15 and 16, substrates K1 and K3 extend to the -Y side, and substrates K2 and K4 extend to the +Z side; as a sixth aspect, as shown in Figures 17 and 18, substrates K1 and K3 extend to the -Y side, and substrates K2 and K4 extend to the -Z side; as a seventh aspect, as shown in Figures 19 and 20, substrates K1 and K3 extend to the -Y side, substrate K2 extends to the -Z side, and substrate K4 extends to the +Z side; and as an eighth aspect, although not shown, substrate K2 in the seventh aspect may extend to the +Z side, and substrate K4 may extend to the -Z side. In these fifth to eighth aspects, the substrates K1, K2, K3, and K4 extend in a direction away from the second cross dichroic prism 5, thereby preventing the adverse effects of heat generated from the substrates K1, K2, K3, and K4 from affecting the optical path in the second cross dichroic prism 5.

[0063] Furthermore, as a ninth aspect, as shown in Figures 21 and 22, substrate K1 extends to the -Y side, substrate K3 extends to the +Y side, substrate K2 extends to the -Z side, and substrate K4 extends to the +Z side; although not shown, as a tenth aspect, in the ninth aspect, substrate K1 extends to the +Y side and substrate K3 extends to the -Y side; as an eleventh aspect, as shown in Figures 23 and 24, substrate K1 extends to the -Y side, substrate K3 extends to the +Y side, substrate K2 extends to the +Z side, and substrate K4 extends to the -Z side; although not shown, as a twelfth aspect, in the eleventh aspect, substrate K1 extends to the +Y side, substrate K3 extends to the -Y side, substrate K2 extends to the +Z side, and substrate K4 extends to the -Z side. In these ninth to twelfth modes, the substrates K1, K2, K3, and K4 extend in different directions, so that the areas occupied by the substrates K1, K2, K3, and K4 at their extension ends become smaller, making them easier to handle.

[0064] 25 and 26, a thirteenth mode is a configuration in which substrate K1 extends on the -Y side, substrate K3 extends on the +Y side, and substrates K2 and K4 extend on the +Z side; a fourteenth mode, not shown, is a configuration in which substrate K1 in the thirteenth mode extends on the +Y side and substrate K3 extends on the -Y side; a fifteenth mode, not shown, is a configuration in which substrate K1 extends on the -Y side, substrate K3 extends on the +Y side, and substrates K2 and K4 extend on the -Z side, as shown in Figures 27 and 28; and a sixteenth mode, not shown, is a configuration in which substrate K1 in the fifteenth mode extends on the -Y side and substrate K3 extends on the +Y side. In these thirteenth to sixteenth modes, two of the substrates K1, K2, K3, and K4 extend in the same direction, allowing for simultaneous substrate arrangement, and the other two extend in different directions, making it easier to handle the extended ends.

[0065] A summary of this disclosure is provided below.

[0066] (Appendix 1) a first electro-optical device that emits first image light of a first color and a first polarization; a second electro-optical device that emits second image light of a second color different from the first color and the first polarization; a third electro-optical device that emits third image light of a third color different from the first color and the second color and the first polarization; a fourth electro-optical device that emits fourth image light of the third color and the second polarization different from the first polarization; a first cross dichroic prism that combines the first image light and the third image light and emits the combined light; a second cross dichroic prism that combines the first combined light, the second image light, and the fourth image light emitted from the first cross dichroic prism and emits the combined light; and a first prism that is arranged on a side of the second cross dichroic prism along a first direction when viewed from an exit surface of the second cross dichroic prism; a composite optical system having a second prism arranged on the surface of the second cross dichroic prism opposite to the surface on which the first prism is arranged, wherein the first electro-optical device is arranged along the first direction and opposite the first entrance surface of the first cross dichroic prism when viewed from the exit surface of the second cross dichroic prism, the third electro-optical device is arranged along the first direction and opposite the second entrance surface of the first cross dichroic prism when viewed from the exit surface of the second cross dichroic prism, and is arranged opposite the first electro-optical device across the first cross dichroic prism, the second electro-optical device is arranged opposite the entrance surface of the first prism, and the fourth electro-optical device is arranged opposite the entrance surface of the second prism.

[0067] As described above, by separately having a third electro-optical device that emits third image light of a third color and a first polarization, and a fourth electro-optical device that emits fourth image light of a third color and a second polarization different from the first polarization, the light intensity density of the third electro-optical device and the fourth electro-optical device can be halved, thereby doubling the light resistance life and improving life reliability.

[0068] As described above, the first electro-optical device and the third electro-optical device are arranged facing the first entrance surface and the second entrance surface of the first cross dichroic prism, and the second electro-optical device and the fourth electro-optical device are arranged facing the entrance surface of the first prism and the entrance surface of the second prism, so that the dimensions in the directions in which the first electro-optical device, the second electro-optical device, the third electro-optical device and the fourth electro-optical device do not face each other are reduced, thereby preventing the optical system from becoming larger.

[0069] (Appendix 2) The projection display device described in Appendix 1, wherein the first electro-optical device, the second electro-optical device, the third electro-optical device, and the fourth electro-optical device are each liquid crystal devices that modulate light from a light source device according to image information to form image light.

[0070] By adopting the configuration of Appendix 2, the dimensions of the liquid crystal device in the direction not facing the first entrance surface, the second entrance surface of the first cross dichroic prism, the entrance surface of the first prism, and the entrance surface of the second prism are reduced, thereby preventing the optical system from becoming larger.

[0071] (Appendix 3) A projection display device as described in Appendix 2, comprising a color separation optical system that separates the light from the light source device into the first color light, the second color light, and the third color light, wherein each of the first electro-optical device, the second electro-optical device, the third electro-optical device, and the fourth electro-optical device is provided with a substrate to which a signal related to the formation of the image light is transmitted, and the substrate extends in a direction away from the color separation optical system.

[0072] By adopting the configuration of Supplementary Note 3, it is possible to prevent adverse effects caused by heat generated from the substrate from affecting the optical path of light in the color separation optical system.

[0073] (Appendix 4) 2. The projection display device according to claim 1, wherein the first electro-optical device, the second electro-optical device, the third electro-optical device, and the fourth electro-optical device each have a self-emitting panel.

[0074] By adopting the configuration of Supplementary Note 4, the dimensions of the self-emitting panel in the direction not facing the first entrance surface, the second entrance surface, the entrance surface of the first prism, and the entrance surface of the second prism are reduced, thereby preventing the optical system from becoming large. In addition, since a color separation optical system is not required, the optical system can be further prevented from becoming large.

[0075] (Appendix 5) A projection display device described in any one of Appendix 1 to Appendix 4, wherein the first cross dichroic prism has a first dichroic surface that transmits the third color light and reflects the first color and the second color light, and a second dichroic surface that transmits the first color and the second color light and reflects the third color light.

[0076] By adopting the configuration of Supplementary Note 5, the first color light and the third color light incident on the first cross dichroic prism 4 can be combined and output to the second cross dichroic prism 5 as the first combined light.

[0077] (Appendix 6) A projection display device described in any one of Appendix 1 to Appendix 4, wherein the first cross dichroic prism has a first dichroic surface that transmits light of the second color and the third color and reflects light of the first color, and a second dichroic surface that transmits light of the first color and reflects light of the second color and the third color.

[0078] By adopting the configuration of Supplementary Note 6, the first color light and the third color light incident on the first cross dichroic prism 4 can be combined and output to the second cross dichroic prism 5 as the first combined light.

[0079] (Appendix 7) 7. The projection display device according to claim 1, wherein the third color is blue.

[0080] By adopting the configuration of Appendix 7, a third electro-optical device that emits blue third image light and a fourth electro-optical device that emits blue fourth image light are used, and therefore, by halving the light density of the third electro-optical device and the fourth electro-optical device, the light resistance life can be doubled, and life reliability can be improved.

[0081] (Appendix 8) 7. The projection display device according to claim 1, wherein the third color is red.

[0082] By adopting the configuration of Appendix 8, a third electro-optical device that emits red third image light and a fourth electro-optical device that emits blue fourth image light are used, and the light density of the third electro-optical device and the fourth electro-optical device can be halved, thereby suppressing the temperature rise of the third electro-optical device and the fourth electro-optical device. [Explanation of symbols]

[0083] 1...Projector (projection display device), 2...Light source device, 4...First cross dichroic prism, 4C...First entrance surface, 4D...Second entrance surface, 5...Second cross dichroic prism, 10...Combining optical system, 11...First prism, 11a...Entrance surface, 12...Second prism, 12a...Entrance surface, K1, K2, K3, K4...Substrate, LG...Green light (first image light), LR...Red light (second image light), LB1...Blue light (third image light), LB2...Blue light (fourth image light), P1...First electro-optical device, P2...Second electro-optical device, P3...Third electro-optical device, P4...Fourth electro-optical device

Claims

1. a first electro-optical device that emits first image light of a first color and a first polarization; a second electro-optical device that emits second image light of a second color different from the first color and a second polarization different from the first polarization; a third electro-optical device that emits third image light of a third color different from the first color and the second color and of the first polarization; a fourth electro-optical device that emits fourth image light of the third color and the second polarization; a combining optical system including: a first cross dichroic prism that combines the first image light and the third image light and emits the combined light; a second cross dichroic prism that combines the first combined light, the second image light, and the fourth image light that are emitted from the first cross dichroic prism and emits the combined light; a first prism that is arranged on a side surface of the second cross dichroic prism along a first direction when viewed from an exit surface of the second cross dichroic prism; and a second prism that is arranged on a surface of the second cross dichroic prism opposite to the surface on which the first prism is arranged; Equipped with the first electro-optical device is disposed along the first direction as viewed from the exit surface of the second cross dichroic prism and facing the first entrance surface of the first cross dichroic prism, the third electro-optical device is disposed along the first direction, as viewed from the exit surface of the second cross dichroic prism, facing the second entrance surface of the first cross dichroic prism, and facing the first electro-optical device across the first cross dichroic prism; the second electro-optical device is disposed opposite to the entrance surface of the first prism, The fourth electro-optical device is a projection display device disposed opposite the entrance surface of the second prism.

2. the first electro-optical device, the second electro-optical device, the third electro-optical device, and the fourth electro-optical device are liquid crystal devices that modulate light from a light source device in accordance with image information to form image light, 2. The projection display device according to claim 1.

3. (Relationship between FPC and POP) a color separation optical system that separates the light from the light source device into the first color light, the second color light, and the third color light, each of the first electro-optical device, the second electro-optical device, the third electro-optical device, and the fourth electro-optical device is provided with a substrate to which a signal related to the formation of the image light is transmitted; the substrate extends in a direction away from the color separation optical system; 3. The projection display device according to claim 2.

4. the first electro-optical device, the second electro-optical device, the third electro-optical device, and the fourth electro-optical device each have a self-emitting panel; 2. The projection display device according to claim 1.

5. The first cross dichroic prism a first dichroic surface that transmits the third color light and reflects the first color light and the second color light; a second dichroic surface that transmits the first color and the second color light and reflects the third color light; having The projection display device according to claim 1 .

6. The first cross dichroic prism a first dichroic surface that transmits the second color and the third color light and reflects the first color light; a second dichroic surface that transmits the first color light and reflects the second color light and the third color light; having The projection display device according to claim 1 .

7. the third color is blue; The projection display device according to claim 1 .

8. The third color is red. The projection display device according to claim 1 .

Images