Projection type display apparatus

Abstract

To provide a projection type display apparatus capable of contributing to improving life reliability and suppressing an increase in size of 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; a first cross dichroic prism that synthesizes the first image light and the third image light, and a second cross dichroic prism that synthesizes and emits the first synthesized light emitted from the first cross dichroic prism and the second image light and the fourth image light. The first electro-optical device and the third electro-optical device are arranged in a first direction with the first cross dichroic prism interposed therebetween, the second electro-optical device and the fourth electro-optical device are arranged in a second direction with the second cross dichroic prism interposed therebetween, and the first electro-optical device, the second electro-optical device, the third electro-optical device, and the fourth electro-optical device are arranged along the same surface.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 it is configured to use four liquid crystal 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; and a first combined light, the second image light, and the fourth image light that are output from the first cross dichroic prism. and a second cross dichroic prism that combines and outputs the combined light, wherein, as viewed from the exit surface of the second cross dichroic prism, the first electro-optical device and the third electro-optical device are arranged along a first direction, sandwiching the first cross dichroic prism therebetween, and as viewed from the exit surface of the second cross dichroic prism, the second electro-optical device and the fourth electro-optical device are arranged along a second direction that intersects the first direction, sandwiching the second cross dichroic prism therebetween, and the first electro-optical device, the second electro-optical device, the third electro-optical device, and the fourth electro-optical device are arranged along the same plane. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a schematic configuration diagram of a projector, which is a projection-type display device according to a first embodiment, viewed from above. [Figure 2] FIG. 3 is a cross-sectional view of a part of the projector viewed in the width direction. [Figure 3] View of the support part from the -Y side. [Figure 4] FIG. 10 is a diagram showing a first pattern of S-polarized light specialized characteristics. [Figure 5] FIG. 10 is a diagram showing a second pattern of S-polarized light specialized characteristics. [Figure 6] 5A and 5B are schematic diagrams illustrating the setting of the size of the light-emitting surface and the size of the incident surface. [Figure 7] FIG. 11 is a view of the support part according to the second embodiment as seen from the -Y side. [Figure 8] FIG. 10 is a schematic configuration diagram of a projector, which is a projection display device according to a second embodiment, viewed from above. [Figure 9] FIG. 11 is a cross-sectional view of a part of a projector according to a second embodiment, viewed in the width direction. [Figure 10] FIG. 10 is a diagram showing a first pattern of S-polarized light specialized characteristics. [Figure 11] FIG. 10 is a diagram showing a first pattern of S-polarized light specialized characteristics. 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 Z direction corresponds to the first direction. The X direction corresponds to the second direction (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 reflected by total reflection mirror 8b and guided to the first electro-optical device P1 with the first polarization via a polarizing plate (not shown).

[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. The total reflection mirror 8e 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 to the third electro-optical device P3 as the first polarization via a polarizing plate (not shown). The third electro-optical device P3 inverts the image because the image is reversed in the Z and Y directions relative to the other electro-optical devices.

[0017] The first electro-optical device P1 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 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, which is different from the first color. Hereinafter, the second image light will be referred to as red light LR. The third electro-optical device P3 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, which is 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 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, which is different from the first and second color lights. Hereinafter, the fourth image light will be referred to as blue light LB2. The first polarized light is, for example, P polarized light, and the second polarized light is, for example, S polarized light.

[0018] 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 supported by a support portion 20. Fig. 3 is a view of the support portion 20 as seen from the -Y side. The support portion 20 is in the shape of a plate and arranged perpendicular to the Y direction.

[0019] 3, when viewed from the exit surface of a second cross dichroic prism 5 (described later), the first electro-optical device P1 and the third electro-optical device P3 are arranged along the first direction, that is, the Z direction, with a first cross dichroic prism 4 (described later) sandwiched therebetween. The first electro-optical device P1 is arranged on the +Z side, and the third electro-optical device P3 is arranged on the -Z side.

[0020] 3, the first electro-optical device P1 and the third electro-optical device P3 are provided with, for example, a flexible FPC (Flexible Printed Circuits) substrate or a COF (Chip on Film) substrate extending opposite the first cross dichroic prism. Therefore, when the vertical scanning directions of the first electro-optical device P1 and the third electro-optical device P3 are the same, the display light in which the green light LG emitted from the first electro-optical device P1 is reflected by the first dichroic surface 4A and emitted from the first cross dichroic prism 4 and the display light in which the blue light LB1 emitted from the third electro-optical device P3 is reflected by the second dichroic surface 4B and emitted from the first cross dichroic prism 4 form vertically inverted images. Therefore, by setting the vertical scanning directions of the first electro-optical device P1 and the third electro-optical device P3 to be opposite directions, the vertical writing of the display light can be performed in the same direction.

[0021] When viewed from the exit surface of the second cross dichroic prism 5, the second electro-optical device P2 and the fourth electro-optical device P4 are arranged along the X direction, which is a second direction intersecting the Z direction, with the second cross dichroic prism 5 in between. The second electro-optical device P2 is arranged on the +X side, and the fourth electro-optical device P4 is arranged on the -X side. 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 arranged along the same plane on the support portion 20.

[0022] 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 right angle prism 11, and a second right angle prism 12.

[0023] The first wire-grid polarizer WG1 is disposed on the +Y side of the first electro-optical device P1. The first wire-grid polarizer WG1 guides the green light LG emitted from the first electro-optical device P1 to the first cross dichroic prism 4. 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.

[0024] The second wire-grid polarizer WG2 is disposed on the +Y side of the third electro-optical device P3. The second wire-grid polarizer WG2 guides the blue light LB1 emitted from the third electro-optical device P3 to the first cross dichroic prism 4. 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.

[0025] 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.

[0026] 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. 4 shows a first pattern of S-polarized light specialization characteristics for white display. As shown in FIG. 4, 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.

[0027] 5 shows a second pattern of S-polarized light specialization characteristics for white display. As shown in FIG. 5, 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.

[0028] 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.

[0029] Therefore, the green light LG and the blue light LB1 incident on the first cross dichroic prism 4 are combined and output to the second cross dichroic prism 5 as a first combined light.

[0030] The first right-angle prism 11 is disposed on the +Y side of the second electro-optical device P2. The first right-angle prism 11 guides the red light LR emitted from the second electro-optical device P2 to the second cross dichroic prism 5. The second right-angle prism 12 is disposed on the +Y side of the fourth electro-optical device P4. The second right-angle prism 12 guides the blue light LB2 emitted from the fourth electro-optical device P4 to the second cross dichroic prism 5.

[0031] An air layer exists between the second electro-optical device P2 and the first right-angle prism 11, and between the fourth electro-optical device P4 and the second right-angle prism 12. Therefore, in order to guide all of the red light LR emitted from the second electro-optical device P2 and the blue light LB2 emitted from the fourth electro-optical device P4 to the second cross dichroic prism 5 without any light leakage, it is necessary to appropriately set the sizes of the light-emitting surfaces of the second electro-optical device P2 and the fourth electro-optical device P4 and the sizes of the incident surfaces of the first right-angle prism 11 and the second right-angle prism 12.

[0032] The settings of the size of the light-emitting surface and the size of the incident surface will be described below. Note that the pair of the second electro-optical device P2 and the first right-angle prism 11, and the pair of the fourth electro-optical device P4 and the second right-angle prism 12 are symmetrical in the X direction, so the pair of the second electro-optical device P2 and the first right-angle prism 11 will be described as a representative example.

[0033] FIG. 6 is a schematic diagram for explaining the setting of the size of the light emitting surface and the size of the incident surface. In FIG. 6, the optical axis J of the red light LR is shown as a single straight line, and the second cross dichroic prism 5 is shown rotated in a direction based on the optical axis J.

[0034] As shown in Figure 6, the effective width of the light-emitting surface PRa in the second electro-optical device P2 is S1. The width of the incident surface 11a of the first right-angle prism 11 is S2. The prism internal half angle of the first right-angle prism 11 is Φ. The refractive index of the first right-angle prism 11 is N, and the prism width W is W. The distance between the light-emitting surface PRa and the incident surface 11a is L. The illumination half angle between the light-emitting surface PRa and the incident surface 11a is θ. The illumination F-number is F.

[0035] The illumination half angle θ is calculated by the following formula (1). θ=arctan(1 / (2×F)) …(1) The half angle Φ within the prism is calculated using the following formula (2). Φ=arcsin((sinθ) / N) …(2) The width S2 of the incident surface 11a is calculated by the following formula (3). S2 = 2 × L × tanθ + S1 … (3) From these, the following formula (4) is satisfied. S1 <W-2×(L×tanθ-2×W×tanΦ) …(4)

[0036] By satisfying the above equation (4), all of the red light LR emitted from the light-emitting surface PRa can be incident on the reflecting surface 11b of the first right-angle prism 11 and can also be incident on the third dichroic surface 5A and the fourth dichroic surface 5B of the second cross dichroic prism 5.

[0037] 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 green light LG and blue light LB1, and the red light LR and blue light LB2 that make up the first combined light have the same emission position in the Y direction, so the optical path lengths to the second cross dichroic prism 5 are approximately the same, and the back focus can be aligned.

[0038] 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.

[0039] Furthermore, in the projection display device of this 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 arranged along the same plane on the support portion 20, which makes it possible to reduce the dimension in at least the Y direction, thereby contributing to preventing the optical system from becoming too large.

[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] 7, the second electro-optical device P2 is disposed on the -X side, and the fourth electro-optical device P4 is disposed on the +X side. 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 disposed along the same plane of the support portion 20.

[0043] 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.

[0044] 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.

[0045] FIG. 8 is a schematic configuration diagram of a projector 1, which is a projection-type display device according to a second embodiment, viewed from above. As shown in FIG. 8, the light source device 2 has laser light sources 2G, 2B, and 2R. The laser light source 2G emits green laser light WG to the +Y side as green light LG. The laser light source 2G is disposed on the -Y side of the first electro-optical device P1 and causes the green light LG to enter the first electro-optical device P1. 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] Fig. 9 is a cross-sectional view seen in the width direction of a part of the projector 1. As shown in Fig. 9, 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. 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 polarized light via a polarizing plate (not shown).

[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. 10 shows a first pattern of S-polarized light specialization patterns for white display. As shown in FIG. 10, 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] 11 is a diagram showing a second pattern of S-polarized light specialization characteristics for white display. As shown in FIG. 11, 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 blue light LB emitted from the second electro-optical device P2 is guided by the second right-angle prism 12 to the second cross dichroic prism 5. The red light LR2 emitted from the fourth electro-optical device P4 is guided by the first right-angle prism 11 to the second cross dichroic prism 5.

[0054] It is preferable that the size of the light-emitting surface of the second electro-optical device P2 and the fourth electro-optical device P4 and the size of the entrance surface of the first rectangular prism 11 and the second rectangular prism 12 satisfy the relationship of the above formula (4).

[0055] 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 green light LG and red light LR1, and the red light LR2 and blue light LB that make up the first combined light have the same emission position in the Y direction, so the optical path lengths to the second cross dichroic prism 5 are approximately the same, and the back focus can be aligned.

[0056] 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.

[0057] 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.

[0058] Furthermore, in the projection display device of this 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 arranged along the same plane on the support portion 20, which makes it possible to reduce the dimension in at least the Y direction, thereby contributing to preventing the optical system from becoming too large.

[0059] 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.

[0060] 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.

[0061] 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 third dichroic surface 5A and the fourth dichroic surface 5B provided on the second cross dichroic prism for the second image light may be set to the same as those for the first polarized light.

[0062] Summary of the Disclosure A summary of this disclosure is provided below.

[0063] (Appendix 1) a first electro-optical device that outputs first image light of a first color and a first polarization; a second electro-optical device that outputs 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 outputs 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 outputs 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 outputs the combined light; and a second cross dichroic prism that combines the first combined light, the second image light, and the fourth image light output from the first cross dichroic prism and outputs the combined light. a composite optical system having a cross dichroic prism and a cross dichroic prism, wherein, as viewed from the exit surface of the second cross dichroic prism, the first electro-optical device and the third electro-optical device are arranged along a first direction, sandwiching the first cross dichroic prism therebetween, and as viewed from the exit surface of the second cross dichroic prism, the second electro-optical device and the fourth electro-optical device are arranged along a second direction that intersects the first direction, sandwiching the second cross dichroic prism therebetween, and the first electro-optical device, the second electro-optical device, the third electro-optical device, and the fourth electro-optical device are arranged along the same plane.

[0064] 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.

[0065] As described above, by arranging the first electro-optical device, the second electro-optical device, the third electro-optical device and the fourth electro-optical device along the same plane, it is possible to reduce the dimension of at least the second cross dichroic prism in the emission direction, which contributes to preventing the optical system from becoming too large.

[0066] (Appendix 2) 2. The projection display device according to claim 1, wherein the first electro-optical device and the third electro-optical device have vertical scanning directions opposite to each other.

[0067] By adopting the configuration of Supplementary Note 2, the writing direction of the display light of the second electro-optical device emitted from the second cross dichroic prism and the writing direction of the display light of the fourth electro-optical device emitted from the second cross dichroic prism can be made the same direction.

[0068] (Appendix 3) The projection display device described in Appendix 1 or 2, 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.

[0069] By adopting the configuration of Appendix 3, the first image light can be reflected by the first dichroic surface and incident on the second cross dichroic prism, and the third image light can be reflected by the second dichroic surface and incident on the second cross dichroic prism.

[0070] (Appendix 4) The projection display device described in Appendix 1 or 2, 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.

[0071] By adopting the configuration of Appendix 4, the first image light can be reflected by the first dichroic surface and incident on the second cross dichroic prism, and the third image light can be reflected by the second dichroic surface and incident on the second cross dichroic prism.

[0072] (Appendix 5) 5. The projection display device according to claim 1, wherein the third color is blue.

[0073] By adopting the configuration of Supplementary Note 5, since the third electro-optical device that emits blue third image light and the fourth electro-optical device that emits blue fourth image light are used, the light resistance life can be doubled by reducing the light quantity density of the third electro-optical device and the fourth electro-optical device by half, and the life reliability can be improved.

[0074] (Supplementary Note 6) The third color is red, and the projection display device according to any one of Supplementary Notes 1 to 4.

[0075] By adopting the configuration of Supplementary Note 6, since the third electro-optical device that emits red third image light and the fourth electro-optical device that emits blue fourth image light are used, the temperature rise of the third electro-optical device and the fourth electro-optical device can be suppressed by reducing the light quantity density of the third electro-optical device and the fourth electro-optical device by half.

[0076] (Supplementary Note 7) A first right-angle prism that reflects the second image light emitted from the second electro-optical device toward the second cross-dichroic prism, and a second right-angle prism that reflects the fourth image light emitted from the fourth electro-optical device toward the second cross-dichroic prism, wherein the effective width of the light-emitting surface in the second electro-optical device and the fourth electro-optical device is S1, the width of the incident surface in the first right-angle prism and the second right-angle prism is S2, the half-angle inside the prism is Φ, the refractive index of the first right-angle prism and the second right-angle prism is N, the prism width is W, the distance between the light-emitting surface and the incident surface is L, the illumination half-angle between the light-emitting surface and the incident surface is θ, and the illumination F-number is F. Then, the projection display device according to any one of Supplementary Notes 1 to 6 satisfies the relationship of S1 < W - 2×(L×tanθ - 2×W×tanΦ).

[0077] By adopting the configuration of Appendix 7, all of the second image light emitted from the light-emitting surface can be incident on the reflecting surface of the first right-angle prism and made to enter the second cross dichroic prism, and all of the fourth image light emitted from the light-emitting surface can be incident on the reflecting surface of the second right-angle prism and made to enter the second cross dichroic prism. [Explanation of symbols]

[0078] 1...Projector (projection type display device), 4...First cross dichroic prism, 5...Second cross dichroic prism, 10...Combining optical system, 11...First right angle prism, 11a...Incident surface, 12...Second right angle prism, 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, P2a...Emitting surface, 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 having 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 outputs the combined light, and a second cross dichroic prism that combines the first combined light, the second image light, and the fourth image light output from the first cross dichroic prism and outputs the combined light, When viewed from the exit surface of the second cross dichroic prism, the first electro-optical device and the third electro-optical device are arranged along a first direction with the first cross dichroic prism therebetween, When viewed from an exit surface of the second cross dichroic prism, the second electro-optical device and the fourth electro-optical device are arranged along a second direction intersecting the first direction with the second cross dichroic prism therebetween, A projection display device in which the first electro-optical device, the second electro-optical device, the third electro-optical device, and the fourth electro-optical device are arranged along the same plane.

2. the first electro-optical device and the third electro-optical device have vertical scanning directions opposite to each other; 2. The projection display device according to claim 1.

3. 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 3. The projection display device according to claim 1.

4. 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 3. The projection display device according to claim 1.

5. the third color is blue; 3. The projection display device according to claim 1.

6. The third color is red.

3. The projection display device according to claim 1.

7. a first right-angle prism that reflects the second image light emitted from the second electro-optical device toward the second cross dichroic prism; a second right-angle prism that reflects the fourth image light emitted from the fourth electro-optical device toward the second cross dichroic prism; and an effective width of the light-emitting surface of each of the second electro-optical device and the fourth electro-optical device is defined as S1; The width of the entrance surface of the first rectangular prism and the second rectangular prism is S2, and the half angle within the prism is Φ, The refractive index of the first rectangular prism and the second rectangular prism is N, and the prism width is W, The distance between the light emitting surface and the incident surface is L, θ is an illumination half angle between the light-emitting surface and the incident surface; If the lighting F-number is F, S1<W-2×(L×tanθ-2×W×tanΦ) Satisfy the relationship between 3. The projection display device according to claim 1.

Images