Projector

Abstract

To provide a projector capable of suppressing deterioration in display quality caused by heat.SOLUTION: A projector comprises: a light source device emitting illumination light including first color light in a first wavelength band and second color light in a second wavelength band different from the first wavelength band; a separating and guiding optical device separating and guiding the illumination light emitted from the light source device; an optical modulator modulating light emitted from the separating and guiding optical device; and a projection optical device projecting light emitted from the optical modulator. The separating and guiding optical device includes a first optical element for separating the illumination light into part of the first color light, other part of the first color light and the second color light. The optical modulator includes a first light modulation element modulating the part of the first color light, and a second light modulation element modulating the other part of the first color light and the second color light. In the illumination light emitted by the light source device, the amount of the first color is greater than the amount of the second color light.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a projector. [Background technology]

[0002] 2. Description of the Related Art In recent years, in order to improve the performance of projectors, projectors have been proposed that include a light source device equipped with a laser light source, which is a light source that has a wide color gamut and is highly efficient.

[0003] For example, the projector disclosed in Patent Document 1 below includes a red light source that emits red laser light, a green light source that emits green laser light, a blue light source that emits blue laser light, and a synthesis optical system that synthesizes the colored lights emitted from the light sources to generate white illumination light, and separates the illumination light into each colored light and causes each colored light to be incident on a liquid crystal panel corresponding to that colored light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2015 / 056381 Summary of the Invention [Problem to be solved by the invention]

[0005] When generating RGB colors with laser light, as in the projector mentioned above, the power required to generate the desired white light differs for each color of light, so the number of laser light sources differs for each color. As a result, the amount of light incident on the LCD panel onto which certain colored light is incident is greater than that on other LCD panels, which creates the problem of reduced display quality due to degradation caused by heat. [Means for solving the problem]

[0006] In order to solve the above problems, a projector according to one aspect of the present invention includes: a projection lens; [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a projector according to a first embodiment. [Diagram 2] 1 is a schematic configuration diagram of a light source device according to a first embodiment. [Diagram 3] FIG. 11 is a diagram illustrating a schematic configuration of a projector according to a second embodiment. [Figure 4] FIG. 13 is a diagram showing a schematic configuration of a light source device according to a third embodiment. [Diagram 5] FIG. 13 is a diagram illustrating a schematic configuration of a projector according to a fourth embodiment. [Figure 6] FIG. 13 is a diagram illustrating a schematic configuration of a projector according to a fifth embodiment. [Figure 7] FIG. 13 is a diagram illustrating a schematic configuration of a projector according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, one embodiment of the present invention will be described. The projector of this embodiment is an example of a projector that uses a liquid crystal panel as a light modulation element of a light modulation device. In the drawings, the dimensions of the components may be shown on different scales in order to make the components easier to see.

[0009] FIG. 1 is a diagram showing a schematic configuration of a projector 1000 according to the present embodiment. 1, a projector 1000 of this embodiment includes a light source device 100, a separation light guiding optical device 200, a light modulation device 400, a cross dichroic prism 500, and a projection optical device 600. The projector 1000 of this embodiment is a projection type image display device that displays a color image on a screen (projection surface) SCR.

[0010] In this embodiment, the light source device 100 emits white illumination light WL that includes a red light beam LR, a green light beam LG, and a blue light beam LB.

[0011] FIG. 2 is a schematic diagram of the light source device 100. As shown in FIG. In the following description, an XYZ Cartesian coordinate system is used as the coordinate axes as necessary. The direction in which illumination light WL is emitted from light source device 100 is the positive direction of the Y axis, the direction in which red light beam LR is emitted from first light source unit 11 described below is the negative direction of the X axis, and the direction perpendicular to the X and Y axes, going from the front to the back of the page, is the positive direction of the Z axis.

[0012] As shown in FIG. 2, the light source device 100 of this embodiment includes a first light source section 11, a second light source section 12, a third light source section 13, a first light combining element 15, a second light combining element 16, a light beam width reduction element 17, a first diffuser plate 19, a second diffuser plate 20, a diffuser 21, a focusing element 22, a pickup element 23, a first phase difference element 24, a first heat sink 27, and a second heat sink 28.

[0013] The first light source unit 11 includes a first light emitting element 31, a first collimator lens 32, and a first substrate 33. The first light emitting element 31 is composed of a red semiconductor laser that emits linearly polarized red light R. The first light emitting element 31 emits red light R of a first wavelength band in the -X direction. Therefore, the first light emitting element 31 emits red light R in a direction perpendicular to the light emission direction of the second light emitting element 34 and the third light emitting element 37. The first wavelength band is, for example, a red wavelength band of 640 nm±10 nm.

[0014] The first collimator lens 32 is provided on the light emission side of the first light-emitting element 31. The first collimator lens 32 is composed of one convex lens provided corresponding to the first light-emitting element 31. The first collimator lens 32 collimates the red light beam R emitted from the first light-emitting element 31.

[0015] The first substrate 33 has a first surface 33a that supports the first light-emitting element 31. That is, the first light-emitting element 31 is supported by the first substrate 33. The first surface 33a extends parallel to the YZ plane. Although seven first light-emitting elements 31 are shown in FIG. 2, in reality, for example, 14 first light-emitting elements 31 are arranged in seven rows of two each in the Z-axis direction. The number of first light-emitting elements 31 is not particularly limited. Therefore, the first light source unit 11 emits a red light beam LR that includes a plurality of red light rays R. The central axis of the red light beam LR emitted from the first light source unit 11 is defined as an optical axis AX1. The red light beam LR of this embodiment corresponds to the "first color light" in the claims.

[0016] The first light source unit 11 is provided on a first heat sink 27. The first heat sink 27 dissipates heat generated in the first light source unit 11 to the outside, thereby cooling the first light source unit 11.

[0017] The second light source unit 12 includes a second light emitting element 34, a second collimator lens 35, and a second substrate 36. The second light emitting element 34 is composed of a green semiconductor laser that emits linearly polarized green light beam G. The second light emitting element 34 emits green light beam G of a second wavelength band in the +Y direction. The second wavelength band is, for example, a green wavelength band of 532 nm±10 nm.

[0018] The second collimator lens 35 is provided on the light emission side of the second light-emitting element 34. The second collimator lens 35 is composed of one convex lens provided corresponding to the second light-emitting element 34. The second collimator lens 35 collimates the green light beam G emitted from the second light-emitting element 34.

[0019] The second substrate 36 has a second surface 36a that supports the second light-emitting element 34. That is, the second light-emitting element 34 is supported by the second substrate 36. The second surface 36a extends parallel to the XZ plane. Although two second light-emitting elements 34 are shown in FIG. 2, in reality, for example, eight second light-emitting elements 34 are arranged in two rows of four in the Z-axis direction. The number of second light-emitting elements 34 is not particularly limited. Therefore, the second light source unit 12 emits a green light beam LG that includes a plurality of green light rays G. The central axis of the green light beam LG emitted from the second light source unit 12 is defined as the optical axis AX. The green light beam LG of this embodiment corresponds to the "second color light" in the claims.

[0020] The third light source unit 13 includes a third light emitting element 37, a third collimator lens 38, and a third substrate 39. The third light emitting element 37 is composed of a blue semiconductor laser that emits linearly polarized blue light B. The third light emitting element 37 emits blue light B of a third wavelength band in the +Y direction. The third wavelength band is, for example, a blue wavelength band of 455 nm±10 nm.

[0021] The third collimator lens 38 is provided on the light emission side of the third light-emitting element 37. The third collimator lens 38 is composed of one convex lens provided corresponding to the third light-emitting element 37. The third collimator lens 38 collimates the blue light beam B emitted from the third light-emitting element 37.

[0022] The third substrate 39 has a third surface 39a that supports the third light emitting element 37. That is, the third light emitting element 37 is supported by the third substrate 39. The third surface 39a extends parallel to the XZ plane. Although one third light emitting element 37 is shown in FIG. 2, in reality, a plurality of third light emitting elements 37, for example, four third light emitting elements 37, are arranged in a row in a direction perpendicular to the paper surface (Z-axis direction). The number of third light emitting elements 37 is not particularly limited. Therefore, the third light source unit 13 emits a blue light beam LB including a plurality of blue light rays B. Hereinafter, in this specification, the term "light beam" is used to collectively refer to the plurality of light beams emitted from the plurality of light emitting elements. The blue light beam LB in this embodiment corresponds to the "third color light" in the claims.

[0023] The second light source unit 12 and the third light source unit 13 are provided on a common second heat sink 28. The second heat sink 28 dissipates heat generated in the second light source unit 12 and the third light source unit 13 to the outside, thereby cooling the second light source unit 12 and the third light source unit 13.

[0024] In general, when laser light sources are used for all of the blue, green, and red light sources, the color gamut of the illumination light is significantly wider than when a light source other than a laser light source is used. Since the color gamut of green is particularly wider among the three colors, in order to adjust the white balance of the illumination light, it is necessary to increase the amount of light of the red light beam relative to the amount of light of the other light beams. As an example, the number of laser light sources for each color is estimated. Generally, the light emission efficiency of a laser light source, the output per unit, the efficiency of the optical system, etc. differ depending on the color, so when estimated taking these into consideration, the number of required laser light sources is, for example, 2 for blue, 10 for green, and 21 for red. In this case, the total output of the multiple laser light sources is 8W for blue, 10W for green, and 32W for red. Here, even if the output per laser light source is 4W and the same for all colors, the number of required laser light sources is 2 for blue, 3 for green, and 8 for red. In any case, the number of required laser light sources is the least for blue and the most for red. In the illumination light WL emitted by the light source device 100 of this embodiment, the amount of red light beam LR is greater than the amount of green light beam LG and the amount of blue light beam LB.

[0025] In this embodiment, the first light source unit 11 emits a red light beam LR consisting of 14 red light rays R emitted from 14 first light-emitting elements 31. The second light source unit 12 emits a green light beam LG consisting of eight green light rays G emitted from eight second light-emitting elements 34. The third light source unit 13 emits a blue light beam LB consisting of four blue light rays B emitted from four third light-emitting elements 37.

[0026] For this reason, the luminous flux width of the green light beam LG emitted from the second light source unit 12 is smaller than the luminous flux width of the red light beam LR emitted from the first light source unit 11. The luminous flux width of the blue light beam LB emitted from the third light source unit 13 is smaller than the luminous flux width of the green light beam LG emitted from the second light source unit 12. By making the luminous flux widths of the light beams of each color different in this manner, the white balance of the illumination light WL emitted from the light source device 100 can be appropriately adjusted.

[0027] The first light combining element 15 includes a light guiding member 40, a first reflecting portion 41, a second reflecting portion 42, and a third reflecting portion 43. In the case of the present embodiment, the first reflecting portion 41, the second reflecting portion 42, and the third reflecting portion 43 are provided in the light guiding member 40. In other words, the first light combining element 15 is configured from a single member in which the first reflecting portion 41, the second reflecting portion 42, the third reflecting portion 43, and the light guiding member 40 are integrated.

[0028] The light guide member 40 has a substantially rectangular prism shape and is made of a light-transmitting material such as optical glass, quartz, etc. The light guide member 40 has a light incident surface 40a facing the first light source unit 11 and the second light source unit 12. The light guide member 40 guides the blue light beam LB between the third reflecting unit 43 and the first reflecting unit 41, and between the first reflecting unit 41 and the second reflecting unit 42.

[0029] The first reflecting portion 41 is provided in the light guide member 40 at a position facing the second light emitting element 34 on the side closer to the third light source unit 13 of the second light source unit 12. The first reflecting portion 41 is provided in a direction forming an angle of 45 degrees with respect to the light incident surface 40a. The first reflecting portion 41 is composed of a dielectric multilayer film provided inside the light guide member 40. The first reflecting portion 41 transmits a part of the blue light beam LB in the -X direction, reflects the other part of the blue light beam LB in the +Y direction intersecting with the -X direction, and transmits the green light beam LG in the +Y direction. In the case of this embodiment, the first reflecting portion 41 transmits 50% of the blue light beam LB incident on the first reflecting portion 41 and reflects the other 50%. In this way, the first reflecting portion 41 functions as a half mirror for the blue light beam LB.

[0030] The second reflecting section 42 is provided in the light guide member 40 at a position facing the second light emitting element 34 on the side of the second light source section 12 farther from the third light source section 13. The second reflecting section 42 is provided at an angle of 45 degrees with respect to the light incident surface 40a and parallel to the first reflecting section 41. Like the first reflecting section 41, the second reflecting section 42 is made of a dielectric multilayer film provided inside the light guide member 40. The second reflecting section 42 reflects the blue light beam LB transmitted through the first reflecting section 41 in the +Y direction and transmits the green light beam LG in the +Y direction. Therefore, the second reflecting section 42 functions as a blue-reflecting / green-transmitting dichroic mirror.

[0031] The third reflecting portion 43 is provided in the light guide member 40 at a position facing the third light emitting element 37 of the third light source unit 13. The third reflecting portion 43 is provided at an angle of 45 degrees with respect to the light incident surface 40a and parallel to the first reflecting portion 41 and the second reflecting portion 42. The third reflecting portion 43 is formed from an end surface of the light guide member 40 formed at an angle of 45 degrees with respect to the light incident surface 40a. The third reflecting portion 43 reflects the blue light beam LB emitted from the third light source unit 13 by total reflection at the interface between the glass material constituting the light guide member 40 and the air, and guides it to the first reflecting portion 41. The third reflecting portion 43 may have a configuration in which a reflective film is provided on the end surface of the light guide member 40.

[0032] With the above configuration, first light combining element 15 expands the beam width of blue light beam LB by splitting blue light beam LB into two beams, and combines blue light beam LB and green light beam LG to generate combined beam LC. The combined beam LC is emitted from first light combining element 15 in the +Y direction.

[0033] In the present embodiment, since the first light combining element 15 has the first reflecting portion 41 and the second reflecting portion 42 spaced apart from each other in the X-axis direction, the light beam width of the blue light beam LB can be adjusted by changing the interval between the first reflecting portion 41 and the second reflecting portion 42. In addition, since the first reflecting portion 41 and the second reflecting portion 42 are integrated by the light guide member 40, the relative positional accuracy between the first reflecting portion 41 and the second reflecting portion 42 can be easily improved. Furthermore, according to this configuration, a support member for supporting the first reflecting portion 41 and the second reflecting portion 42 is not required, which contributes to miniaturization of the light source device 100.

[0034] The second light combining element 16 is provided on the optical axis AX between the first light combining element 15 and the diffusion device 21. The second light combining element 16 is disposed at a position where the optical axis AX and the optical axis AX1 intersect with each other, and is oriented so as to form an angle of 45 degrees with each of the optical axes AX and AX1. The second light combining element 16 is composed of a dichroic mirror that reflects the red light beam LR and transmits the blue light beam LB and the green light beam LG. With the above configuration, the second light combining element 16 combines the combined light beam LC including the blue light beam LB and the green light beam LG with the red light beam LR to generate the illumination light WL. The illumination light WL is emitted from the second light combining element 16 in the +Y direction. The second light combining element 16 in this embodiment corresponds to the "light combining optical system" in the claims.

[0035] The light beam width reduction element 17 is provided on the optical axis AX1 between the first light source unit 11 and the second light combining element 16. The light beam width reduction element 17 reduces the light beam width of the red light beam LR emitted from the first light source unit 11. Specifically, the light beam width reduction element 17 reduces the light beam width of the red light beam LR emitted from the light beam width reduction element 17 to be smaller than the light beam width of the red light beam LR incident on the light beam width reduction element 17 so as to approach the light beam width of the green light beam LG. The light beam width reduction element 17 is composed of an afocal optical element. The afocal optical element of this embodiment is composed of one convex lens and one concave lens, but the number of lenses is not particularly limited. Since the light beam width reduction element 17 is composed of an afocal optical element, the red light beam LR incident on the light beam width reduction element 17 is emitted from the light beam width reduction element 17 as a parallel light beam. Furthermore, since the light beam width reduction element 17 is made of an afocal optical element, the structure of the light beam width reduction element 17 can be simplified.

[0036] Furthermore, since the light beam width reduction element 17 is provided in front of the second light combining element 16, the red light beam LR after its light beam width has been reduced enters the second light combining element 16. With this configuration, the second light combining element 16 can be made compact, and the light source device 100 can be made compact.

[0037] The first phase difference element 24 is disposed on the optical axis AX1 between the first light source unit 11 and the light beam width reduction element 17. The first phase difference element 24 is, for example, a rotatable half-wave plate. In the case of the light source device 100 of this embodiment, the red light beam LR emitted from the first light source unit 11 and incident on the first phase difference element 24 is aligned to one of the P-polarized component and the S-polarized component. According to this configuration, since linearly polarized light is incident on the first phase difference element 24, by appropriately setting the rotation angle of the first phase difference element 24, the red light beam LR passing through the first phase difference element 24 can be easily converted into a light beam containing a P-polarized component (first polarization component) and an S-polarized component (second polarization component) relative to the first optical element 210 described later at a predetermined ratio. By rotating the first phase difference element 24, the ratio of the S-polarized component to the P-polarized component can be changed. In other words, the first phase difference element 24 changes the ratio of P-polarized light and S-polarized light, which is the polarization state of the red light beam LR.

[0038] Hereinafter, the P-polarized component of the red light beam LR will be referred to as red light LRp, and the S-polarized component of the red light beam LR will be referred to as red light LRs. In other words, the first phase difference element 24 can generate a red light beam LR containing a P-polarized component and an S-polarized component at a predetermined ratio. In this embodiment, the first phase difference element 24 adjusts the polarization ratio in the red light beam LR so that the amount of S-polarized component red light LRs is smaller than the amount of P-polarized component red light LRp.

[0039] The first diffusion plate 19 is provided on the optical axis AX between the first light combining element 15 and the second light combining element 16. The first diffusion plate 19 diffuses the combined light beam LC emitted from the first light combining element 15. The second diffusion plate 20 is provided on the optical axis AX1 between the first light source unit 11 and the second light combining element 16. The second diffusion plate 20 diffuses the red light beam LR emitted from the first light source unit 11.

[0040] The diffusion device 21 is provided between the second light combining element 16 and the pickup element 23, i.e., on the optical axis AX on the light emission side of the second light combining element 16. The diffusion device 21 includes a third diffusion plate 45 and a motor 47 that rotates the third diffusion plate 45 about a rotation axis 46. The third diffusion plate 45 diffuses the illumination light WL emitted from the second light combining element 16.

[0041] The first diffusion plate 19, the second diffusion plate 20, and the third diffusion plate 45 have the same configuration. Although not shown, one surface of these diffusion plates is provided with an uneven structure for diffusing the light beam incident on the diffusion plate. The uneven structure may be a structure in which a plurality of concaves and convexities having irregular shapes and sizes are formed, or a structure in which a plurality of microlenses are arranged. Note that, as other forms of the diffusion plate, frosted glass, a holographic diffuser, a transparent substrate subjected to blasting, a transparent substrate in which scattering material is dispersed, and the like may be used. These diffusion plates are composed of a transmission type diffusion plate that transmits and diffuses the light beam incident on the diffusion plate. Note that, like the third diffusion plate 45, the first diffusion plate 19 and the second diffusion plate 20 may also be rotatable.

[0042] Thus, the light source device 100 of the present embodiment includes a first diffuser plate 19 that diffuses the composite light beam LC, a second diffuser plate 20 that diffuses the red light beam LR, and a third diffuser plate 45 that diffuses the illumination light WL. With this configuration, the illuminance distribution of the light beams of each color can be made uniform, so that color unevenness of the image can be reduced. In addition, since the light beams of each color, which are coherent light emitted from the semiconductor laser, are diffused, speckle noise of the image can be suppressed when applied to the projector 1000. In addition, since the illumination light WL is diffused by the third diffuser plate 45, the irradiation area of ​​the illumination light WL is expanded, and the overlapping property of the illumination light WL in the image formation area of ​​the light modulation device can be increased. As a result, color unevenness of the image can be efficiently suppressed.

[0043] The light collecting element 22 is provided on the optical axis AX between the second light combining element 16 and the third diffuser plate 45. In the present embodiment, the light collecting element 22 is configured with one convex lens, but the number of lenses is not particularly limited. The light collecting element 22 collects the illumination light WL emitted from the second light combining element 16 toward the third diffuser plate 45.

[0044] The pickup element 23 is provided on the optical axis AX on the light emission side of the third diffusion plate 45. In the present embodiment, the pickup element 23 is composed of two convex lenses, but the number of lenses is not particularly limited. The pickup element 23 collimates the illumination light WL diffused by the third diffusion plate 45, and emits it toward the separation light guiding optical device 200 at the downstream side.

[0045] 1, the separation light guiding optical device 200 includes a first optical element 210, a dichroic mirror 220, a first mirror 230, a second mirror 240, a third mirror 250, a relay lens 260, and a relay lens 270. The separation light guiding optical device 200 separates the illumination light WL emitted from the light source device 100 into a red light beam LR, a green light beam LG, and a blue light beam LB, and guides each of the separated light beams to the light modulation device 400. The light modulation device 400 of this embodiment includes a first light modulation element 400R, a second light modulation element 400G, and a third light modulation element 400B.

[0046] Specifically, the separation light guiding optical device 200 of this embodiment separates the illumination light WL into a part of the red light beam LR, another part of the red light beam LR, a green light beam LG, and a blue light beam LB. The separation light guiding optical device 200 guides the part of the red light beam LR to the first light modulation element 400R, guides the other part of the red light beam LR and the green light beam LG to the second light modulation element 400G, and guides the blue light beam LB to the third light modulation element 400B.

[0047] The red light beam LR emitted from the light source device 100 of this embodiment is put into a polarization state in which P-polarized components and S-polarized components with respect to the first optical element 210 are mixed by transmitting through the first phase difference element 24 as described above.

[0048] The first optical element 210 is disposed on the optical axis of the illumination light WL incident from the light source device 100. The first optical element 210 is a polarization separation element, such as a polarizing beam splitter, having a polarization separation function for the red light beam LR of the illumination light WL. The first optical element 210 of this embodiment has an optical characteristic of reflecting the green light beam LG and the blue light beam LB other than the red light beam LR, regardless of the polarization direction. The first optical element 210 can separate the red light beam LR while suppressing losses such as absorption and reflection by polarization separation. Therefore, the light utilization efficiency of the red light beam LR can be improved.

[0049] The first optical element 210 separates the illumination light WL into a part of the red light beam LR, another part of the red light beam LR, a green light beam LG, and a blue light beam LB. Specifically, the first optical element 210 transmits red light LRp, which is a P-polarized component of the red light beam LR, and reflects red light LRs, which is an S-polarized component of the red light beam LR. The first optical element 210 also has an optical characteristic of reflecting the green light beam LG and the blue light beam LB regardless of the polarization direction. In this embodiment, the red light LRp corresponds to "a part of the first color light" in the claims, and the red light LRs corresponds to "another part of the first color light" in the claims.

[0050] In this embodiment, as described above, the amount of red light LRs, which is an S-polarized component, of the red light flux LR is smaller than the amount of red light LRp, which is a P-polarized component, by the first optical element 210. Therefore, the amount of red light LRp that transmits through the first optical element 210 is greater than the amount of red light LRs reflected by the first optical element 210. Therefore, the amount of red light LRp that enters the first light modulation element 400R is greater than the amount of red light LRs that enters the second light modulation element 400G.

[0051] In this embodiment, as described later, the green light beam LG is incident on the second light modulation element 400G in addition to the red light LRs, but the total amount of light incident on the second light modulation element 400G is smaller than the amount of red light LRp incident on the first light modulation element 400R, or the total amount of red light beam LR including red light LRp and red light LRs. Also, the amount of blue light beam LB incident on the third light modulation element 400B is smaller than the amount of red light LRp incident on the first light modulation element 400R. That is, in the projector 1000 of this embodiment, the amount of light incident on each of the first light modulation element 400R, the second light modulation element 400G, and the third light modulation element 400B is smaller than the amount of red light beam LR, which is the greatest amount of illumination light WL.

[0052] The red light LRp transmitted through the first optical element 210 is reflected by the first mirror 230 and enters the first light modulation element 400R. A field lens 300R is disposed between the first mirror 230 and the first light modulation element 400R. The first light modulation element 400R is formed of a liquid crystal panel, and modulates the red light LRp based on image information to form red image light.

[0053] The red light LRp incident on the first light modulation element 400R as a P-polarized component is modulated by the first light modulation element 400R and converted into an S-polarized component by passing through the light exit side polarizing plate. In other words, the red image light modulated by the first light modulation element 400R is incident on the cross dichroic prism 500 as an S-polarized component.

[0054] The cross dichroic prism 500 of this embodiment needs to combine the red light incident from two mutually orthogonal directions. In general, it is desirable to design the dielectric multilayer film of the cross dichroic prism so as to transmit the P-polarized component and reflect the S-polarized component from the viewpoint of ease of film design. In this embodiment, the red image light emitted from the first light modulation element 400R is incident on the cross dichroic prism 500 as an S-polarized component, and is reflected by the dielectric multilayer film of the cross dichroic prism 500 and is favorably emitted toward the projection optical device 600.

[0055] The red light LRs, the green light beam LG, and the blue light beam LB reflected by the first optical element 210 are incident on the dichroic mirror 220. The dichroic mirror 220 separates the red light LRs, the green light beam LG, and the blue light beam LB. The dichroic mirror 220 transmits the blue light beam LB and reflects the red light LRs and the green light beam LG toward the second light modulation element 400G. A field lens 300G is disposed between the dichroic mirror 220 and the second light modulation element 400G. The second light modulation element 400G is formed of a liquid crystal panel, and modulates the red light LRs and the green light beam LG based on image information to form yellow image light containing red and green colors.

[0056] The red light LRs incident on the second light modulation element 400G as an S-polarized component is modulated by the second light modulation element 400G and is converted to a P-polarized component by passing through the light exit side polarizing plate. The polarization direction of the green light beam LG is adjusted in advance so that it becomes an S-polarized component with respect to the second light modulation element 400G, and the green light beam LG is converted to a P-polarized component by passing through the polarizing plate arranged on the light exit side of the second light modulation element 400G. In this embodiment, the yellow image light is incident on the cross dichroic prism 500 as a P-polarized component, and therefore passes well through the dielectric multilayer film of the cross dichroic prism 500 and is emitted toward the projection optical device 600.

[0057] The blue light beam LB transmitted through the dichroic mirror 220 is reflected successively by the second mirrors 240 and 250 and enters the third light modulation element 400B. A field lens 300B is disposed between the third mirror 250 and the third light modulation element 400B. The third light modulation element 400B is formed of a liquid crystal panel, and modulates the blue light beam LB based on image information to form blue image light.

[0058] In the present embodiment, for example, by adjusting the polarization direction of the blue light beam LB in advance so that it becomes a P-polarized component with respect to the third light modulation element 400B, the blue light beam LB is modulated by the third light modulation element 400B and is converted into an S-polarized component by transmitting through the light exit side polarizing plate. Since the blue image light is incident on the cross dichroic prism 500 as an S-polarized component, it is reflected well by the dielectric multilayer film of the cross dichroic prism 500 and is emitted toward the projection optical device 600.

[0059] Although not shown, incident-side polarizing plates are arranged between the field lens 300R and the first light modulation element 400R, between the field lens 300G and the second light modulation element 400G, and between the field lens 300B and the third light modulation element 400B. Also, exit-side polarizing plates are arranged between the first light modulation element 400R and the cross dichroic prism 500, between the second light modulation element 400G and the cross dichroic prism 500, and between the third light modulation element 400B and the cross dichroic prism 500.

[0060] The cross dichroic prism 500 forms a color image by synthesizing the image lights emitted from the first light modulation element 400R, the second light modulation element 400G, and the third light modulation element 400B. The cross dichroic prism 500 has a substantially square shape in a plan view formed by bonding four right-angle prisms together, and has a configuration in which a dielectric multilayer film is provided at the substantially X-shaped interface formed by bonding the right-angle prisms together. In this embodiment, the cross dichroic prism 500 corresponds to the "composite prism" in the claims.

[0061] The color image emitted from the cross dichroic prism 500 is enlarged and projected onto a projection surface such as a screen SCR by the projection optical device 600. The projection optical device 600 is composed of a plurality of lenses.

[0062] As described above, the projector 1000 of this embodiment includes the light source device 100 that emits illumination light WL including a red light beam LR in a red wavelength band and a green light beam LG in a green wavelength band different from the red wavelength band, the separation light guiding optical device 200 that separates and guides the illumination light WL emitted from the light source device 100, the light modulation device 400 that modulates the light emitted from the separation light guiding optical device 200, and the projection optical device 600 that projects the light emitted from the light modulation device 400. The separation light guiding optical device 200 has a first optical element 210 that separates the illumination light WL into red light LRp that is a part of the red light beam LR, red light LRs that is another part of the red light beam LR, a green light beam LG, and a blue light beam LB. The light modulation device 400 includes a first light modulation element 400R that modulates the red light LRp, a second light modulation element 400G that modulates the red light LRs and the green light beam LG, and a third light modulation element 400B that modulates the blue light beam LB. In the illumination light WL emitted by the light source device 100, the amount of light of the red light beam LR is greater than the amount of light of the green light beam LG.

[0063] Here, because the basic structure of each of the light modulation elements 400R, 400G, and 400B is the same, the damage caused by heat to each element is proportional to the amount of light incident thereon. For this reason, if the maximum amount of red light beam LR is incident on the first light modulation element 400R, the first light modulation element 400R will be damaged by heat and will deteriorate faster, which may result in a decrease in quality, such as color unevenness, in the image projected by the projector. In contrast, according to the projector 1000 of this embodiment, the red light beam LR having the greatest light amount among the illumination light WL is separated into red light LRp and LRs, and the red light LRp is made incident on the first light modulation element 400R while the red light LRs is made incident on the second light modulation element 404B. This makes it possible to prevent a large amount of light from being concentrated on the first light modulation element 400R, and to prevent a decrease in display quality due to deterioration caused by heat of the first light modulation element 400R. In addition, in the projector 1000 of this embodiment, the amount of light incident on each light modulation element 400R, 400G, 400B is set to be smaller than the maximum amount of red light beam LR in the illumination light WL. This reduces the difference in the amount of light incident on each light modulation element 400R, 400G, 400B, thereby suppressing light from being incident on a specific light modulation element in a concentrated manner, and by matching the rate of deterioration due to heat of each light modulation element 400R, 400G, 400B, it is possible to provide a highly reliable projector capable of projecting high-quality images for a long period of time.

[0064] Second embodiment Next, a projector according to a second embodiment will be described. The difference between this embodiment and the first embodiment is the configuration of the separated light guiding optical device. Therefore, the configuration of the separated light guiding optical device will be mainly described below, and the same reference numerals will be used for the members common to the above embodiment, and detailed description will be omitted.

[0065] FIG. 3 is a diagram showing a schematic configuration of a projector 1002 according to the present embodiment. 3, a projector 1002 of this embodiment includes a light source device 100, a separation light guiding optical device 202, a light modulation device 400, a cross dichroic prism 500, and a projection optical device 600. Note that the projector 1002 of this embodiment differs from the projector 1002 of the first embodiment in the incident direction of illumination light WL with respect to the separation light guiding optical device 202.

[0066] The separation light guiding optical device 202 includes a first optical element 212, a dichroic mirror 220, a first mirror 230, a second mirror 240, a third mirror 250, a relay lens 260, a relay lens 270, and a second phase difference element 282. The separation light guiding optical device 202 separates the illumination light WL emitted from the light source device 100 into a red light beam LR, a green light beam LG, and a blue light beam LB, and guides each of the separated light beams to the light modulation device 400.

[0067] The first optical element 212 is disposed on the optical axis of the illumination light WL incident from the light source device 100. The first optical element 210 is a polarization separation element, such as a polarizing beam splitter, having a polarization separation function for the red light beam LR of the illumination light WL. The first optical element 212 of this embodiment has an optical characteristic of transmitting the green light beam LG and the blue light beam LB other than the red light beam LR, regardless of the polarization direction.

[0068] The first optical element 212 transmits red light LRp, which is the P-polarized component of the red light beam LR, and reflects red light LRs, which is the S-polarized component of the red light beam LR. The first optical element 212 also has an optical characteristic of transmitting the green light beam LG and the blue light beam LB regardless of the polarization direction. In this embodiment, the red light LRs corresponds to "a part of the first color light" in the claims, and the red light LRp corresponds to "another part of the first color light" in the claims.

[0069] In the light source device 100 of the projector 1002 of this embodiment, the polarization ratio of the red light flux LR is adjusted by the rotation angle of the first optical element 210 so that the amount of red light LRp, which is a P-polarized component, is smaller than the amount of red light LRs, which is an S-polarized component. Therefore, the amount of red light LRs reflected by the first optical element 212 is greater than the amount of red light LRp that transmits through the first optical element 212.

[0070] The red light LRs reflected by the first optical element 212 is reflected by the first mirror 230 and enters the first light modulation element 400R. The first light modulation element 400R modulates the red light LRs based on image information to form red image light. In the case of the projector 1002 of this embodiment, the red image light modulated by the first light modulation element 400R enters the cross dichroic prism 500 as a P-polarized component.

[0071] In the case of the projector 1002 of this embodiment, the cross dichroic prism 500 reflects the red image light toward the projection optical device 600, so as described above, it is desirable for the first light modulation element 400R to emit the red image light as an S-polarized component to the cross dichroic prism 500.

[0072] In contrast, the projector 1002 of this embodiment further includes a third phase difference element 283 arranged on the light incident side of the first light modulation element 400R. The third phase difference element 283 changes the polarization state of the red light LRs. The third phase difference element 283 is composed of a half-wave plate, and converts the S-polarized component of the red light LRs into a P-polarized component of red light LRp1. The red light LRp1 corresponds to the "first polarized component" in the claims.

[0073] The red light LRp1 transmitted through the third phase difference element 283 enters the first light modulation element 400R. The first light modulation element 400R modulates the red light LRp1 based on image information to form red image light. The red light LRp1 incident on the first light modulation element 400R as a P-polarized component is converted to an S-polarized component by transmitting through a polarizing plate arranged on the light exit side of the first light modulation element 400R. That is, the red image light LRs1 modulated by the first light modulation element 400R enters the cross dichroic prism 500 as an S-polarized component. Therefore, the red image light LRs1 is reflected by the dielectric multilayer film of the cross dichroic prism 500 and exits toward the projection optical device 600.

[0074] The red light LRp, green light beam LG, and blue light beam LB transmitted through the first optical element 212 are incident on the dichroic mirror 220. The dichroic mirror 220 separates the red light LRp, green light beam LG, and blue light beam LB. The dichroic mirror 220 transmits the blue light beam LB and reflects the red light LRp and green light beam LG toward the second light modulation element 400G.

[0075] As described above, it is preferable that the light emerging from the second light modulation element 400G is incident as a P-polarized component on the cross dichroic prism 500. In other words, it is necessary to cause an S-polarized component of light to be incident on the second light modulation element 400G.

[0076] In this embodiment, the red light LRp is incident on the second light modulation element 400G as a P-polarized component (first polarized component). The polarization direction of the green light beam LG may be adjusted in advance so that the green light beam LG becomes an S-polarized component with respect to the second light modulation element 400G.

[0077] In contrast to this, the separation light guiding optical device 202 of the present embodiment further includes a second phase difference element 282 disposed on the optical path between the light exit side of the dichroic mirror 220 and the second light modulation element 400G. Note that the second phase difference element 282 does not have to be a part of the components of the separation light guiding optical device 202.

[0078] The second phase difference element 282 is composed of a narrowband phase difference plate that imparts a phase difference of 1 / 2 wavelength to light in the red wavelength band and does not impart a phase difference to light in other wavelength bands. Therefore, the second phase difference element 282 imparts a phase difference of 1 / 2 wavelength to the red light LRp and does not impart a phase difference to the green light beam LG. Therefore, the second phase difference element 282 converts the red light LRp of the P-polarized component into the red light LRs2 of the S-polarized component (second polarization component), and does not change the polarization state of the green light beam LG.

[0079] The red light LRs2 transmitted through the second phase difference element 282 enters the second light modulation element 400G. The second light modulation element 400G modulates the red light LRs2 based on image information to form red image light. The red light LRs2 incident on the second light modulation element 400G as an S-polarized component is modulated by the second light modulation element 400G and converted into a P-polarized component by transmitting through the light exit side polarizing plate. That is, the red image light LRp2 modulated by the second light modulation element 400G enters the cross dichroic prism 500 as a P-polarized component. Therefore, the red image light LRp2 transmits through the dielectric multilayer film of the cross dichroic prism 500 and is emitted toward the projection optical device 600.

[0080] The green light beam LG transmitted through the second phase difference element 282 is modulated by the second light modulation element 400G and is converted into green image light LG1 of a P-polarized component by transmitting through the light-exiting-side polarizing plate. Therefore, the green image light LG1 transmits through the dielectric multilayer film of the cross dichroic prism 500 and is emitted toward the projection optical device 600.

[0081] The blue light beam LB transmitted through the dichroic mirror 220 is reflected by the second mirrors 240 and 250 in sequence and enters the third light modulation element 400B. In the present embodiment as well, the polarization direction of the blue light beam LB is adjusted in advance to be a P-polarized component for the third light modulation element 400B, so that the blue light beam LB is modulated by the third light modulation element 400B and converted into an S-polarized component by passing through the light exit side polarizing plate. In other words, the blue image light LB1 modulated by the third light modulation element 400B enters the cross dichroic prism 500 as an S-polarized component, and is therefore well reflected by the dielectric multilayer film of the cross dichroic prism 500 and exits toward the projection optical device 600.

[0082] In this way, even when the incident direction of the illumination light WL with respect to the separation light guiding optical device 202 is changed as in the projector 1002 of this embodiment, the red light LRs can be made to enter the first light modulation element 400R while the red light LRp can be made to enter the second light modulation element 404B. This makes it possible to prevent a large amount of light from being concentratedly incident on the first light modulation element 400R and to prevent a decrease in display quality due to deterioration caused by heat of the first light modulation element 400R. In addition, by providing the second phase difference element 282 and the third phase difference element 283, a projector can be provided that adjusts the polarization components of the image light generated by each light modulation element 400R, 404G, 404B and projects a color image by combining each image light by the cross dichroic prism 500.

[0083] In this embodiment, the second phase difference element 282 is disposed on the light incident side of the second light modulation element 400G, but the second phase difference element 282 may be disposed on the light exit side of the second light modulation element 400G. In this case, the second phase difference element 282 converts the green image light emitted as S-polarized light from the light exit side polarizing plate of the second light modulation element 400G into P-polarized light and causes it to enter the cross dichroic prism 500.

[0084] In addition, in the present embodiment, the third phase difference element 283 is disposed on the light incident side of the first light modulation element 400R, but the third phase difference element 283 may be disposed on the light exit side of the first light modulation element 400R. In this case, the third phase difference element 283 may convert the red image light emitted as P-polarized light from the light exit side polarizing plate of the first light modulation element 400R into S-polarized light and cause it to enter the cross dichroic prism 500.

[0085] Third embodiment Next, a projector according to a third embodiment will be described. The difference between this embodiment and the first embodiment is the configuration of the light source device. Therefore, the following mainly describes the configuration of the light source device, and the same reference numerals are used for the members common to the above embodiments, and detailed descriptions are omitted.

[0086] FIG. 4 is a diagram showing a schematic configuration of the light source device of this embodiment. As shown in FIG. 4, the light source device 103 of this embodiment includes a first light source section 11, a second light source section 12, a third light source section 13, a first light combining element 15, a second light combining element 16, a light beam width reduction element 17, a first diffuser plate 19, a second diffuser plate 20, a diffuser 21, a focusing element 22, a pickup element 23, a first heat sink 27, a second heat sink 28, a lens integrator 50, a polarization conversion element 53, and a superimposing lens 54.

[0087] The lens integrator 50 has a first multi-lens 51 and a second multi-lens 52. The first multi-lens 51 has a plurality of first small lenses 51a for splitting the illumination light WL into a plurality of partial ray bundles.

[0088] The surface of the first small lenses 51a, which is the lens surface of the first multi-lens 51, and the image forming areas of the light modulation elements 400R, 400G, and 400B are conjugate with each other. Therefore, the shape of each of the first small lenses 51a is approximately similar to the shape of the image forming areas of the light modulation elements 400R, 400G, and 400B. As a result, each of the partial light beams emitted from the first multi-lens 51 efficiently enters the image forming areas of the light modulation elements 400R, 400G, and 400B.

[0089] The second multi-lens 52 has a plurality of second small lenses 52a corresponding to the plurality of first small lenses 51a of the first multi-lens 51. The second multi-lens 52, together with the superimposing lens 54, forms an image of each of the first small lenses 51a of the first multi-lens 51 in the vicinity of the image forming area of ​​each of the light modulation elements 400R, 400G, and 400B.

[0090] The illumination light WL transmitted through the lens integrator 50 is incident on a polarization conversion element 53 . The polarization conversion element 53 of this embodiment converts the polarization directions of the red light beam LR, the green light beam LG, and the blue light beam LB separated from the illumination light WL into polarization directions that transmit the incident-side polarizing plates arranged on the light incident sides of the light modulation elements 400R, 400G, and 400B. By aligning the polarization direction of the illumination light WL using the polarization conversion element 53 in this way, the light utilization efficiency of the illumination light WL can be further improved.

[0091] The polarization conversion element 53 of this embodiment converts a part of the red light beam LR into a P-polarized red light LRp, and converts another part of the red light beam LR into an S-polarized red light LRs. The polarization conversion element 53 also converts the green light beam LG and the blue light beam LB into S-polarized components. That is, the polarization conversion element 53 of this embodiment has optical properties that convert light in the red wavelength band into a polarization state in which S-polarized light and P-polarized light are mixed, and convert the green light beam LG and the blue light beam LB in wavelength bands different from the red wavelength band into predetermined linear polarization.

[0092] The configuration of the polarization conversion element 53 will be described below. The polarization conversion element 53 of this embodiment has a plurality of polarization separation layers 53a, a plurality of reflective layers 53b, a plurality of retardation layers 53c, and a light-shielding film 53d. The retardation layer 53c is provided on the light-emitting side of the polarization conversion element 53. The polarization conversion element 53 includes a plurality of entrance openings 53K through which the illumination light WL emitted from the diffusion device 21 passes. Each entrance opening 53K is formed by an opening formed in the light-shielding film 53d arranged on the light-incident surface side of the polarization conversion element 53. The planar shape of the entrance opening 53K is a rectangle having a longitudinal side in the Z-axis direction.

[0093] The polarization separation layer 53a is composed of a polarization separation film that separates all incident light of all wavelength bands into P-polarized light and S-polarized light. The phase difference layer 53c has an optical characteristic of imparting a phase difference of 1 / 2 wavelength to the green light beam LG and the blue light beam LB other than the red wavelength band, and imparting a phase difference shifted from 1 / 2 wavelength to the light of the red wavelength band. By transmitting through the polarization conversion element 53 having such a configuration, the red light beam LR contained in the illumination light WL is made into a polarization state in which S-polarized light and P-polarized light are mixed, and the green light beam LG and the blue light beam LB contained in the illumination light WL can be made into a predetermined linearly polarized light. As another method, S-polarized light and P-polarized light may be mixed by having an optical characteristic of imparting a phase difference of 1 / 2 wavelength to a part of the red wavelength band on the short wavelength band side and not imparting a phase difference to a part of the red wavelength band on the long wavelength band side.

[0094] Thus, according to the light source device 103 of the present embodiment, by using the polarization conversion element 53 instead of the first phase difference element 24 of the first embodiment, it is possible to generate a red light flux LR containing a predetermined ratio of P-polarized components and S-polarized components. Therefore, even in a projector in which the light source device 100 of the first embodiment is replaced with the light source device 103 of the present embodiment, it is possible to obtain the same effect of providing a highly reliable projector capable of projecting high-quality images for a long period of time by suppressing the concentrated incidence of light on a predetermined light modulation element and matching the rate of deterioration due to heat of each of the light modulation elements 400R, 400G, and 400B.

[0095] (Fourth embodiment) Next, a projector according to a fourth embodiment will be described. The difference between this embodiment and the second embodiment is that the light modulation elements into which the blue and green light beams separated from the illumination light are incident are switched. Below, the configuration relating to the difference in the optical paths of the blue and green light beams will be mainly described, and the same reference numerals will be used for the members common to the above embodiments, and detailed description will be omitted.

[0096] FIG. 5 is a diagram showing a schematic configuration of the projector of the present embodiment. As shown in FIG. 5, a projector 1004 of this embodiment includes a light source device 100, a separation light guiding optical device 204, a light modulation device 404, a cross dichroic prism 504, and a projection optical device 600.

[0097] The light modulation device 404 of this embodiment includes a first light modulation element 400R, a second light modulation element 404B, and a third light modulation element 404G. The separation light guiding optical device 204 of this embodiment guides red light LRs, which is a part of the red light beam LR, to the first light modulation element 400R, guides red light LRp and a blue light beam LB, which are the other parts of the red light beam LR, to the second light modulation element 404B, and guides the green light beam LG to the third light modulation element 404G.

[0098] The separation light-guiding optical device 204 includes a first optical element 212 , a dichroic mirror 224 , a first mirror 230 , a second mirror 240 , a third mirror 250 , a relay lens 260 , a relay lens 270 , and a second phase difference element 282 .

[0099] In the light separation and guiding optical device 204 of this embodiment, the dichroic mirror 224 separates the red light LRp, the green light beam LG, and the blue light beam LB. The dichroic mirror 224 transmits the green light beam LG and reflects the red light LRp and the blue light beam LB toward the second light modulation element 404B. The green light beam LG transmitted through the dichroic mirror 224 is reflected in sequence by the second mirror 240 and the third mirror 250, and enters the third light modulation element 404G.

[0100] The second light modulation element 404B modulates the red light LRp and the blue light beam LB based on image information and emits the modulated light as image light. The third light modulation element 404G modulates the green light beam LG based on image information and emits the modulated light as image light. Note that the second light modulation element 404B and the third light modulation element 404G are the same as the other light modulation elements in the above embodiment, and therefore the description thereof will be omitted.

[0101] The cross dichroic prism 504 of this embodiment has a first dielectric multilayer film 504a and a second dielectric multilayer film 504b. The first dielectric multilayer film 504a has a property of reflecting the red image light LRs3, which is an S-polarized component incident from the first light modulation element 400R, and transmitting the red image light LRp3 and blue image light LB2, which are P-polarized components incident from the second light modulation element 404B, and the green image light LG2, which is an S-polarized component incident from the third light modulation element 404G. The second dielectric multilayer film 504b has a property of reflecting the green image light LG2, and transmitting the blue image light LB2 and the red image lights LRs3 and LRp3. It is possible to design the first dielectric multilayer film 504a and the second dielectric multilayer film 504b having such properties.

[0102] According to the projector 1004 of this embodiment, the red light LRs separated from the illumination light WL can be made incident on the first light modulation element 400R, the red light LRp and the blue light beam LB can be made incident on the second light modulation element 404B, and the green light beam LG can be made incident on the third light modulation element 404G. This makes it possible to prevent a large amount of light from being concentrated on the first light modulation element 400R, and to prevent a decrease in display quality due to deterioration caused by heat of the first light modulation element 400R. In addition, by reducing the difference in the amount of light incident on each light modulation element 400R, 404G, and 404B, it is possible to prevent light from being concentrated on a specific light modulation element, and by matching the rate of thermal deterioration of each light modulation element 400R, 404G, and 404B, it is possible to provide a highly reliable projector that can project high-quality images over a long period of time.

[0103] In addition, in the projector 1002 of the second embodiment, a configuration in which the red light LRp is incident on the third light modulation element 400B together with the blue light beam LB is also conceivable. However, in this configuration, it is necessary to design a dielectric multilayer film capable of reflecting the S-polarized and P-polarized red lights incident from the parallel faces of the cross dichroic prism, but designing a film with such characteristics is difficult to realize. For this reason, when the S-polarized and P-polarized red lights are incident on the cross dichroic prism, it can be said that the design of the dielectric multilayer film is feasible if the layout of the projector 1004 of the present embodiment in which the S-polarized and P-polarized red lights are incident on two adjacent faces of the cross dichroic prism, one polarized light is reflected, and the other polarized light is transmitted to combine them is used.

[0104] Fifth embodiment Next, a projector according to a fifth embodiment will be described. The difference between this embodiment and the first embodiment is the configuration of the separation light guiding optical device that separates the red light from the illumination light into two and the position of the light source device. The following mainly describes the configuration of the separation light guiding optical device, and the same reference numerals are used for the members common to the above embodiments, and detailed description will be omitted.

[0105] FIG. 6 is a diagram showing a schematic configuration of the projector of the present embodiment. As shown in FIG. 6, a projector 1005 of this embodiment includes a light source device 105, a separation light guiding optical device 205, a light modulation device 400, a cross dichroic prism 500, and a projection optical device 600.

[0106] The light source device 105 of this embodiment has a configuration in which the first phase difference element 24 of the light source device 100 of the first embodiment is omitted, and emits illumination light WL1 including a red light beam LR that is linearly polarized. In this embodiment, the red light beam LR included in the illumination light WL1 is S-polarized light with respect to the incident-side polarizers of the first light modulation element 400R and the second light modulation element 400G.

[0107] The separation light guiding optical device 205 includes a first optical element 215, a dichroic mirror 220, a first mirror 230, a second mirror 240, a third mirror 250, a relay lens 260, and a relay lens 270. The separation light guiding optical device 205 separates the illumination light WL1 emitted from the light source device 105 into a red light beam LR, a green light beam LG, and a blue light beam LB, and guides each of the separated light beams to the light modulation elements 400R, 400G, and 400B of the light modulation device 400.

[0108] The first optical element 215 has a color separation film 215a, a half mirror film 215b, and a transparent substrate 215c. The color separation film 215a is provided on one surface of the transparent substrate 215c, which is the light incident side, and is composed of a dichroic film that transmits the red light beam LR and reflects the green light beam LG and the blue light beam LB. The half mirror film 215b is provided on the other surface of the transparent substrate 215c, and is a mirror that transmits a part of the red light beam LR that has transmitted through the color separation film 215a and reflects the other part. The other part of the red light reflected by the half mirror film 215b transmits through the transparent substrate 215c and the color separation film 215a and is emitted toward the dichroic mirror 220. Note that the half mirror film 215b and the half mirror film 215b are not limited to having the same transmittance and reflectance for the red light beam LR, and may have different transmittances and reflectances. In this embodiment, the half mirror film 215b is designed so that the transmittance is higher than the reflectance, as described later. In this embodiment, the half mirror film 215b corresponds to the "optical film" in the claims.

[0109] The first optical element 215 separates the illumination light WL1 into a part of the red light beam LR, another part of the red light beam LR, a green light beam LG, and a blue light beam LB. Specifically, the first optical element 215 transmits red light LR1, which is a part of the red light beam LR, and reflects red light LR2, which is the other part of the red light beam LR. The first optical element 215 also reflects the blue light beam LB and the green light beam LG. In this embodiment, the red light LR1 corresponds to "a part of the first color light" in the claims, and the red light LR2 corresponds to "another part of the first color light" in the claims.

[0110] In this embodiment, the half mirror film 215b of the first optical element 215 is designed so that the amount of red light LR1, which is transmitted light, is greater than the amount of red light LR2, which is reflected light.

[0111] The red light LR1 transmitted through the first optical element 215 is reflected by the first mirror 230 and enters the first light modulation element 400R. The first light modulation element 400R modulates the red light LR1 based on image information to form red image light. The red light LR1 incident on the first light modulation element 400R as an S-polarized component is modulated by the first light modulation element 400R and converted into red image light as a P-polarized component by transmitting through the light exit side polarizing plate.

[0112] Since the cross dichroic prism 500 reflects the light incident from the first light modulation element 400R, it is desirable that the first light modulation element 400R emits the red image light as an S-polarized component to the cross dichroic prism 500 as described above.

[0113] In contrast, the projector 1005 of this embodiment further includes a fourth phase difference element 284 arranged on the light emission side of the first light modulation element 400R. The fourth phase difference element 284 is configured with a ½ wavelength plate, and converts the light incident from the first light modulation element 400R from an S-polarized component to red image light LR3 which is a P-polarized component.

[0114] The image light LR 3 transmitted through the fourth phase difference element 284 is incident on the cross dichroic prism 500 as an S-polarized component, and is reflected by the dielectric multilayer film of the cross dichroic prism 500 to emerge towards the projection optical device 600 .

[0115] The red light LR2, green light beam LG, and blue light beam LB reflected by the first optical element 215 are incident on the dichroic mirror 220. The dichroic mirror 220 transmits the blue light beam LB and reflects the red light LR2 and green light beam LG toward the second light modulation element 400G. The second light modulation element 400G modulates the red light LR2 and green light beam LG based on image information to form yellow image light.

[0116] The red light LR2 incident on the second light modulation element 400G as an S-polarized component is modulated by the second light modulation element 400G and converted to a P-polarized component by passing through the light exit side polarizing plate. The green light beam LG is converted to a P-polarized component by passing through the polarizing plate arranged on the light exit side of the second light modulation element 400G by adjusting the polarization direction in advance so that the green light beam LG becomes an S-polarized component with respect to the second light modulation element 400G. In this embodiment, the yellow image light LY consisting of the modulated light of the red light LR2 and the green light beam LG is incident on the cross dichroic prism 500 as a P-polarized component, and therefore passes well through the dielectric multilayer film of the cross dichroic prism 500 and is emitted toward the projection optical device 600.

[0117] As described above, the blue light beam LB transmitted through the dichroic mirror 220 is incident on the third light modulation element 400B via the second mirror 240 and the third mirror 250. The configuration and operation of the third light modulation element 400B are the same as those in the second embodiment. Therefore, the blue image light LB1 is incident on the cross dichroic prism 500 as an S-polarized component, and is thus transmitted well through the dielectric multilayer film of the cross dichroic prism 500 and emitted toward the projection optical device 600.

[0118] In this way, according to the projector 1005 of the present embodiment, by using the half mirror film 215b, it is possible to easily separate red light LR1, LR2 from the red light flux LR consisting of linearly polarized light contained in the illumination light WL1, and distribute and cause the separated red light LR1, LR2 to be incident on the first light modulation element 400R and the second light modulation element 400G. This makes it possible to prevent a large amount of light from being incident on the first light modulation element 400R in a concentrated manner, and to prevent a decrease in display quality due to deterioration caused by heat of the first light modulation element 400R. In addition, by being equipped with a fourth phase difference element 284, the projector 1005 of this embodiment can adjust the polarization components of the image light generated by each light modulation element 400R, 404G, and 404B, and project a color image by combining each image light by the cross dichroic prism 500.

[0119] In this embodiment, the red light LR1 reflected by the first optical element 215 is incident on the first light modulation element 400R, and the red light LR2 transmitted through the first optical element 215 is incident on the second light modulation element 400G, but it is also possible to cause the red light transmitted through the first optical element 215 to be incident on the first light modulation element 400R, and the red light reflected by the first optical element 215 to be incident on the second light modulation element 400G.

[0120] Sixth embodiment Next, a projector according to a sixth embodiment will be described. The difference between this embodiment and the first embodiment is the configuration in which red light is separated from illumination light into two. The following mainly describes the configuration of the separation light guide optical device, and the same reference numerals are used for the members common to the above embodiments, and detailed descriptions are omitted.

[0121] FIG. 7 is a diagram showing a schematic configuration of the projector of the present embodiment. As shown in FIG. 7, a projector 1006 of this embodiment includes a light source device 106, a separation light guiding optical device 206, a light modulation device 400, a cross dichroic prism 500, and a projection optical device 600.

[0122] The light source device 106 of this embodiment has a configuration in which the first phase difference element 24 is omitted from the light source device 100 of the first embodiment and replaced with a first light source section 116 that emits a red light beam LR0 including a plurality of red wavelength bands. The first light source section 116 includes a light emitting element 116a, a light emitting element 116b, and a light emitting element 116c. The numbers of the light emitting elements 116a, 116b, and 116c are appropriately adjusted according to the wavelength band of the red light beam LR.

[0123] The light emitting element 116a is a semiconductor laser that emits a red light beam R1 of 643 nm in the red wavelength band (first wavelength band). The light emitting element 116b is a semiconductor laser that emits a red light ray R2 of 639 nm, which is in the red wavelength band (first wavelength band) and has a shorter wavelength than the light emitting element 116a. The light emitting element 116c is a semiconductor laser that emits a red light beam R3 of 647 nm, which is a longer wavelength than that of the light emitting element 116a, in the red wavelength band (first wavelength band).

[0124] Based on such a configuration, the light source device 106 of this embodiment emits illumination light WL2 including a red light beam LR0 having a plurality of red wavelength bands. The red light beam LR0 of this embodiment corresponds to the "first colored light" in the claims. In this embodiment, the red light beam LR0 included in the illumination light WL2 is S-polarized light with respect to the incident-side polarizers of the first light modulation element 400R and the second light modulation element 400G.

[0125] The separation light guiding optical device 206 includes a first optical element 216, a dichroic mirror 220, a first mirror 230, a second mirror 240, a third mirror 250, a relay lens 260, and a relay lens 270. The separation light guiding optical device 206 separates the illumination light WL2 emitted from the light source device 106 into a red light beam LR0, a green light beam LG, and a blue light beam LB, and guides each of the separated light beams to the light modulation elements 400R, 400G, and 400B of the light modulation device 400.

[0126] The first optical element 216 is composed of a dichroic mirror having optical properties of transmitting the longer wavelength light of the red light beam LR contained in the illumination light WL2 and reflecting the shorter wavelength light of the red light beam LR and the blue light beam LB and green light beam LG contained in the illumination light WL2.

[0127] The first optical element 216 separates the illumination light WL2 into a part of the red light beam LR0, another part of the red light beam LR0, a green light beam LG, and a blue light beam LB. Specifically, the first optical element 216 transmits red light LR01 on the long wavelength side of the red light beam LR0, and reflects red light LR02 on the short wavelength side of the red light beam LR0. The red light LR01 is light that includes red light rays R1 and R3 on the long wavelength side out of the light emitted by the first light source unit 116, and the red light LR02 is light that includes red light ray R2 on the short wavelength side out of the light emitted by the first light source unit 116. In this embodiment, the red light LR01 corresponds to "a part of the first color light" in the claims, and the red light LR02 corresponds to "another part of the first color light" in the claims. Moreover, the first optical element 216 reflects the blue light beam LB and the green light beam LG.

[0128] In this embodiment, the number and light emission amount of each of the light emitting elements 116a, 116b, 116c of the first light source section 116 are adjusted so that the amount of red light LR01, which is transmitted light, is greater than the amount of red light LR02, which is reflected light.

[0129] The red light LR01 transmitted through the first optical element 216 is reflected by the first mirror 230 and enters the first light modulation element 400R as a P-polarized component, where it is modulated by the first light modulation element 400R and converted into an S-polarized component by transmitting through a polarizing plate on the light exit side. Note that, by adjusting the polarization direction of the red light rays R1 and R3 constituting the red light LR01 in advance so that they become P-polarized components with respect to the first light modulation element 400R, the red light LR01 is converted into red image light LR4, an S-polarized component, by transmitting through a polarizing plate arranged on the light exit side of the first light modulation element 400R.

[0130] The image light LR 4 is incident on the cross dichroic prism 500 as an S-polarized component, and is reflected by the dielectric multilayer film of the cross dichroic prism 500 and emitted towards the projection optical device 600 .

[0131] The red light LR02, green light beam LG, and blue light beam LB reflected by the first optical element 216 are incident on the dichroic mirror 220. The dichroic mirror 220 transmits the blue light beam LB and reflects the red light LR02 and green light beam LG toward the second light modulation element 400G. The second light modulation element 400G modulates the red light LR02 and green light beam LG based on image information to form yellow image light.

[0132] The red light LR02 incident on the second light modulation element 400G as an S-polarized component is modulated by the second light modulation element 400G and converted to a P-polarized component by passing through a polarizing plate on the light exit side. Note that the polarization direction of the red light beam R2 constituting the red light LR02 is adjusted in advance so that it becomes an S-polarized component with respect to the second light modulation element 400G, and the red light LR02 is converted to a P-polarized component by passing through a polarizing plate arranged on the light exit side of the second light modulation element 400G. Also, the polarization direction of the green light beam LG is adjusted in advance so that it becomes an S-polarized component with respect to the second light modulation element 400G, and the green light beam LG is converted to a P-polarized component by passing through a polarizing plate arranged on the light exit side of the second light modulation element 400G. In this embodiment, the yellow image light LY2 composed of the modulated light of the red light LR02 and the green light beam LG is incident on the cross dichroic prism 500 as a P-polarized component, and therefore passes through the dielectric multilayer film of the cross dichroic prism 500 well and is emitted toward the projection optical device 600.

[0133] As described above, the blue light beam LB transmitted through the dichroic mirror 220 is incident on the third light modulation element 400B via the second mirror 240 and the third mirror 250. The configuration and operation of the third light modulation element 400B are the same as those in the first embodiment. Therefore, the blue image light LB1 is incident on the cross dichroic prism 500 as an S-polarized component, and is thus transmitted well through the dielectric multilayer film of the cross dichroic prism 500 and emitted toward the projection optical device 600.

[0134] In this way, according to the projector 1006 of the present embodiment, the red light beam LR0 having a plurality of red wavelength bands contained in the illumination light WL2 can be separated into long wavelength side and short wavelength side red light LR01, LR02, which can be distributed and made incident on the first light modulation element 400R and the second light modulation element 400G. This makes it possible to prevent a large amount of light from being incident on the first light modulation element 400R in a concentrated manner, and to prevent a decrease in display quality due to deterioration caused by heat of the first light modulation element 400R.

[0135] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. In the above embodiment, when the amount of light of the red light beam LR in the illumination light emitted from the light source device is the largest, the red light beam LR is separated into two and distributed to two light modulation elements. That is, the first color light in the first wavelength band is the red light beam LR, but the present invention is not limited to this.

[0136] For example, the present invention can also be applied to a case where the green light beam LG, which has the greatest light intensity among the illumination light, is split into two and distributed to two light modulation elements, or a case where the blue light beam LB, which has the greatest light intensity among the illumination light, is split into two and distributed to two light modulation elements.

[0137] The following is a summary of this disclosure. (Appendix 1) a light source device that emits illumination light including a first color light in a first wavelength band and a second color light in a second wavelength band different from the first wavelength band; a light separation and guiding optical device that separates and guides the illumination light emitted from the light source device; a light modulation device that modulates the light emitted from the separation light guiding optical device; a projection optical device that projects the light emitted from the light modulation device, the light separation and guiding optical device has a first optical element that separates the illumination light into a part of the first color light and another part of the first color light and the second color light; the light modulation device includes a first light modulation element that modulates the portion of the first color light, and a second light modulation element that modulates the other portion of the first color light and the second color light, In the illumination light emitted by the light source device, the amount of the first color light is greater than the amount of the second color light. projector.

[0138] According to the projector having this configuration, it is possible to separate a part of the first color light having a large amount of light from the illumination light and to cause the part of the first color light to enter the first light modulation element while causing the other part of the first color light to enter the second light modulation element. This makes it possible to prevent a large amount of light from being concentrated into the first light modulation element and to prevent a decrease in display quality due to deterioration of the first light modulation element caused by heat. In addition, by reducing the difference in the amount of light incident on the first light modulation element and the second light modulation element, it is possible to prevent light from being concentrated on one of the light modulation elements, and by matching the rate of thermal deterioration of each light modulation element, it is possible to provide a highly reliable projector that can project high-quality images over a long period of time.

[0139] (Appendix 2) the first optical element is a polarization separation element that transmits a first polarization component of the first color light having a first polarization direction and reflects a second polarization component of the first color light having a second polarization direction different from the first polarization component; 2. The projector according to claim 1.

[0140] According to this configuration, the first optical element can efficiently separate the first color light by polarization separation while suppressing losses such as absorption and reflection, thereby improving the light utilization efficiency of the first color light.

[0141] (Appendix 3) The light source device is a first light source unit that emits the first color light; a second light source unit that emits the second color light; a light combining optical system that combines the first color light and the second color light; a first phase difference element that is disposed on an optical path between the first light source unit and the light combining optical system and changes the polarization state of the first color light; 1. The projector according to claim 2.

[0142] According to this configuration, by appropriately setting the rotation angle of the first phase difference element, the first color light passing through the first phase difference element can be converted into light containing a first polarization component and a second polarization component in a predetermined ratio.

[0143] (Appendix 4) The first color light emitted from the first light source unit and incident on the first phase difference element is one of the first polarized component and the second polarized component. 4. The projector according to claim 3.

[0144] According to this configuration, by making the first color light consisting of linearly polarized light incident on the first phase difference element, it is possible to efficiently convert the polarization state of the first color light as described above.

[0145] (Appendix 5) the light source device further includes a polarization conversion element that converts the incident light into the first polarization component or the second polarization component; the polarization conversion element converts the portion of the first color light into one of the first polarization component and the second polarization component, and converts the other portion of the first color light and the second color light into the other of the first polarization component and the second polarization component. 1. The projector according to claim 2.

[0146] According to this configuration, the polarization conversion element can convert the first color light into light containing the first polarized component and the second polarized component at a predetermined ratio.

[0147] (Appendix 6) the separation light guiding optical device has a second phase difference element disposed on an optical path between the first optical element and the second optical modulation element, the second phase difference element converts the other part of the first color light, which is the first polarization component transmitted through the first optical element, into the second polarization component, and does not impart a phase difference to the second color light transmitted through the first optical element. 1. The projector according to claim 2.

[0148] According to this configuration, the second phase difference element can adjust the polarization components of the image light generated by the second light modulation element, which allows a color image to be projected by properly combining the image lights using a combining prism, which will be described later.

[0149] (Appendix 7) a third phase difference element arranged on the light incident side of the first optical modulation element and converting the part of the first color light, which is the second polarized component reflected by the first optical element, into the first polarized component; 7. The projector according to claim 6.

[0150] According to this configuration, the third phase difference element can adjust the polarization components of the image light generated by the first light modulation element, which allows a color image to be projected by properly combining the image lights using a combining prism, which will be described later.

[0151] (Appendix 8) a synthesis prism that synthesizes the light incident from the first light modulation element and the light that is emitted from the second light modulation element and enters from a direction different from the light that is incident from the first light modulation element, the composite prism reflects the light incident from the first light modulation element and transmits the light emitted from the second light modulation element; the first polarization component is a P polarization component with respect to the composite prism, the second polarized component is an S polarized component with respect to the composite prism, the second light modulation element outputs the other part of the first color light incident from the second phase difference element as a P-polarized component to the composite prism; 8. The projector according to claim 7.

[0152] The composite prism needs to combine the red light incident from two different directions. In general, it is desirable to design the dielectric multilayer film of the composite prism to transmit the P-polarized component and reflect the S-polarized component from the viewpoint of ease of film design. With this configuration, the light emitted from the first light modulation element is incident on the composite prism as an S-polarized component, and can be reflected well by the dielectric multilayer film of the composite prism. In addition, the light emitted from the second light modulation element is incident as a P-polarized component via the second phase difference element, and can be transmitted well through the dielectric multilayer film of the composite prism. Therefore, the composite prism can combine the light emitted from the first light modulation element and the second light modulation element well.

[0153] (Appendix 9) the first color light is linearly polarized, the first optical element includes an optical film that transmits one of the portion of the first color light and the other portion of the first color light and reflects the other of the portion of the first color light and the other portion of the first color light, 2. The projector according to claim 1.

[0154] According to this configuration, the first color light, which is linearly polarized light, can be easily separated into two light beams by the optical film of the first optical element.

[0155] (Appendix 10) the first optical element transmits one of the light on the long wavelength side of the first colored light and the light on the short wavelength side of the first colored light, and reflects the other of the light on the long wavelength side of the first colored light and the light on the short wavelength side of the first colored light, 2. The projector according to claim 1.

[0156] According to this configuration, the first color light can be easily separated into light on the long wavelength side and light on the short wavelength side by the first optical element.

[0157] (Appendix 11) the illumination light emitted from the light source device further includes a third color light of a third wavelength band different from the first wavelength band and the second wavelength band, The light modulation device further includes a third light modulation element that modulates the third color light. 11. The projector according to claim 1.

[0158] According to this configuration, it is possible to provide a highly reliable three-plate projector capable of projecting high-quality images for a long period of time by suppressing deterioration of each light modulation element due to heat.

[0159] (Appendix 12) the first light modulation element is a red light liquid crystal panel, the second light modulation element is a liquid crystal panel for green light, The third light modulation element is a liquid crystal panel for blue light. 12. The projector according to claim 11.

[0160] According to this configuration, it is possible to provide a projector that can project high-quality color images for a long period of time.

[0161] (Appendix 13) the amount of the other portion of the first color light is smaller than the amount of the other portion of the first color light; 13. The projector according to claim 1,

[0162] According to this configuration, by suppressing the amount of light incident on the second light modulation element, it is possible to reduce the difference between the amount of light incident on the first light modulation element and the second light modulation element. [Explanation of symbols]

[0163] 11, 116...first light source unit, 12...second light source unit, 16...second light combining element (light combining optical system), 24...first phase difference element, 53...polarization conversion element, 100, 103, 105, 106...light source device, 200, 202, 204, 205, 206...separation light guiding optical device, 210, 212, 215, 216...first optical element, 215a...half mirror film (optical film), 282...second phase difference element, 283...third phase difference element, 400, 404...light modulation device, 400R...first light modulation element, 400G, 404B...second light modulation element, 400 B, 404G...third light modulation element, 500...cross dichroic prism (combining prism), 600...projection optical device, 1000, 1002, 1004, 1005, 1006...projector, LR, LR0...red light beam (first color light), LRp, LRs, LR1, LR01...red light (part of the first color light), LRs, LRp, LR2, LR02...red light (another part of the first color light), LRp1...red light (first polarized component), LG...green light beam (second color light), LB...blue light beam (third color light), WL, WL1, WL2...illumination light.

Claims

1. a light source device that emits illumination light including a first color light in a first wavelength band and a second color light in a second wavelength band different from the first wavelength band; a light separation and guiding optical device that separates and guides the illumination light emitted from the light source device; a light modulation device that modulates the light emitted from the separation light guiding optical device; a projection optical device that projects the light emitted from the light modulation device, the separation light guide optical device has a first optical element that separates the illumination light into a part of the first color light, another part of the first color light, and the second color light; the light modulation device includes a first light modulation element that modulates the portion of the first color light, and a second light modulation element that modulates the other portion of the first color light and the second color light, In the illumination light emitted by the light source device, the amount of the first color light is greater than the amount of the second color light. projector.

2. the first optical element is a polarization separation element that transmits a first polarization component of the first color light having a first polarization direction and reflects a second polarization component of the first color light having a second polarization direction different from the first polarization component; The projector according to claim 1 .

3. The light source device is a first light source unit that emits the first color light; a second light source unit that emits the second color light; a light combining optical system that combines the first color light and the second color light; a first phase difference element that is disposed on an optical path between the first light source unit and the light combining optical system and changes the polarization state of the first color light; The projector according to claim 2 .

4. The first color light emitted from the first light source unit and incident on the first phase difference element is one of the first polarized component and the second polarized component. The projector according to claim 3 .

5. the light source device further includes a polarization conversion element that converts the incident light into the first polarization component or the second polarization component, the polarization conversion element converts the portion of the first color light into one of the first polarization component and the second polarization component, and converts the other portion of the first color light and the second color light into the other of the first polarization component and the second polarization component. The projector according to claim 2 .

6. the separation light guiding optical device has a second phase difference element disposed on an optical path between the first optical element and the second optical modulation element, the second phase difference element converts the other part of the first color light, which is the first polarization component transmitted through the first optical element, into the second polarization component, and does not impart a phase difference to the second color light transmitted through the first optical element. The projector according to claim 2 .

7. a third phase difference element arranged on a light incident side of the first light modulation element and configured to convert the part of the first color light, which is the second polarized component reflected by the first optical element, into the first polarized component; The projector according to claim 6.

8. a synthesis prism that synthesizes the light incident from the first light modulation element and the light that is emitted from the second light modulation element and is incident from a direction different from the light that is incident from the first light modulation element, the composite prism reflects the light incident from the first light modulation element and transmits the light emitted from the second light modulation element; the first polarization component is a P polarization component with respect to the composite prism, the second polarized component is an S polarized component with respect to the composite prism, the second light modulation element outputs the other part of the first color light incident from the second phase difference element as a P-polarized component to the composite prism; The projector according to claim 7.

9. the first color light is linearly polarized, the first optical element includes an optical film that transmits one of the portion of the first color light and the other portion of the first color light and reflects the other of the portion of the first color light and the other portion of the first color light, The projector according to claim 1 .

10. the first optical element transmits one of the light on the long wavelength side of the first color light and the light on the short wavelength side of the first color light and reflects the other of the light on the long wavelength side of the first color light and the light on the short wavelength side of the first color light, The projector according to claim 1 .

11. the illumination light emitted from the light source device further includes a third color light of a third wavelength band different from the first wavelength band and the second wavelength band, the light modulation device further includes a third light modulation element that modulates the third color light; The projector according to any one of claims 1 to 10.

12. the first light modulation element is a red light liquid crystal panel, the second light modulation element is a liquid crystal panel for green light, The third light modulation element is a liquid crystal panel for blue light. The projector according to claim 11.

13. an amount of the other portion of the first color light is smaller than an amount of the other portion of the first color light; The projector according to any one of claims 1 to 10.

Images