Projector

Abstract

To provide a projector that can improve the light use efficiency.SOLUTION: A projector of the present invention includes a light source that emits light including first laser light in a first wavelength band, a first polarization element formed of a dielectric multilayer film and separating a first polarization component out of the first laser light that is incident, a first transmission type liquid crystal panel that modulates the first polarization component out of the first laser light that is separated by the first polarization element, and a projection optical system that projects light modulated by the first transmission type liquid crystal panel. The first polarization element separates the first polarization component out of the first laser light to make the first polarization component enter the first transmission type liquid crystal panel.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] 2. Description of the Related Art Conventionally, when using high-density light such as laser light in a projector, it is known to use a polarizing plate with a wire grid structure as the incident-side polarizing plate of a liquid crystal panel (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-003209 A Summary of the Invention [Problem to be solved by the invention]

[0004] A polarizing plate having the above-mentioned wire grid structure has a problem in that when transmitting light of a predetermined polarization direction, loss occurs due to interfacial reflection on the surface, etc., resulting in a decrease in light utilization efficiency. [Means for solving the problem]

[0005] In order to solve the above problem, a projector of one embodiment of the present invention includes a light source that emits light including a first laser light of a first wavelength band, a first polarizing element formed of a dielectric multilayer film that separates a first polarized component of the incident first laser light, a first transmissive liquid crystal panel that modulates the first polarized component of the first laser light separated by the first polarizing element, and a projection optical system that projects the light modulated by the first transmissive liquid crystal panel, wherein the first polarizing element separates the first polarized component of the first laser light, thereby causing the first polarized component to be incident on the first transmissive liquid crystal panel. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a projector according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing a configuration of a lighting device. [Diagram 3] 4 is a graph showing the spectral characteristics of a first polarizing element. [Figure 4] FIG. 11 is a diagram illustrating a schematic configuration of a projector according to a second embodiment. [Diagram 5] FIG. 11 is a diagram illustrating a schematic configuration of a projector according to a second embodiment. [Figure 6] 13 is a graph showing the spectral characteristics of a second polarizing element. [Figure 7] FIG. 13 is a diagram illustrating a schematic configuration of a projector according to a fourth embodiment. [Figure 8] 13 is a graph showing the spectral characteristics of a second polarizing element. [Figure 9] FIG. 13 is a diagram illustrating a schematic configuration of a projector according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, an 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 device. In the drawings, the dimensions of the components may be shown on different scales in order to make the components easier to see.

[0008] (First embodiment) FIG. 1 is a diagram showing a schematic configuration of a projector 100 according to the present embodiment. 1, the projector 100 of this embodiment is a projection type image display device that displays an image on a screen SCR. The projector 100 includes an illumination device 120, a color separation optical system 130, light modulation devices 140R, 140G, and 140B, a color synthesis optical system 150, and a projection optical system 160. The projector 100 is a three-plate type projector having three light modulation devices.

[0009] The lighting device 120 emits illumination light WL toward the color separation optical system 130. The illumination light WL is illumination light in the projector 100, and includes red light LR, green light LG, and blue light LB.

[0010] FIG. 2 is a diagram showing the configuration of the lighting device 120. As shown in FIG. As shown in FIG. 2, the illumination device 120 includes a light source 2, a lens integrator 31, a polarization conversion element 32, and a superimposing lens 33.

[0011] The light source 2 has a light emitting element 20a, a first phase difference element 21, an optical element 22, a first light collecting optical system 23, a second light collecting optical system 24, a wavelength conversion element 25, a diffusion element 26, and a second phase difference element 27. The light emitting element 20a, the first phase difference element 21, the optical element 22, the first light collecting optical system 23, and the wavelength conversion element 25 are sequentially arranged on an optical axis ax1. The optical axis ax1 is the optical axis of the light emitting element 20a.

[0012] The diffusion element 26, the second focusing optical system 24, the second phase difference element 27, and the optical element 22, which constitute the light source 2, the lens integrator 31, the polarization conversion element 32, and the superimposing lens 33 are sequentially arranged in a line on the illumination optical axis ax2. The optical axis ax1 and the illumination optical axis ax2 are in the same plane and are perpendicular to each other.

[0013] The light emitting element 20a is composed of a semiconductor laser. The light emitting element 20a emits a blue light beam E in a blue wavelength band of, for example, 445 nm to 460 nm. Note that a semiconductor laser that emits a laser beam in a wavelength band other than the above may also be used as the light emitting element 20a. Note that the number of light emitting elements 20a is not particularly limited and may be one or more.

[0014] The first phase difference element 21 is disposed on the optical path of the blue light beam E between the light emitting element 20a and the optical element 22. The first phase difference element 21 is, for example, a rotatable half-wave plate. The blue light beam E emitted from the light emitting element 20a is linearly polarized light. By appropriately setting the rotation angle of the first phase difference element 21, the blue light beam E passing through the first phase difference element 21 can be a light beam containing an S-polarized component (first polarized component) and a P-polarized component (second polarized component) relative to the optical element 22 at a predetermined ratio. By rotating the first phase difference element 21, the ratio of the S-polarized component and the P-polarized component can be changed. That is, the first phase difference element 21 distributes the blue light beam E from the light emitting element 20a into an S-polarized component and a P-polarized component.

[0015] The blue light ray E, which contains an S-polarized component and a P-polarized component and is generated by passing through the first phase difference element 21 , is incident on the optical element 22 . The optical element 22 is disposed to form an angle of 45° with respect to the optical axis ax1 and the illumination optical axis ax2. The optical element 22 has a polarization separation function that separates the blue light ray E into a light ray Es having an S-polarized component and a light ray Ep having a P-polarized component with respect to the optical element 22. The optical element 22 is formed of, for example, a plate-type polarization separation element. In addition, the optical element 22 has a color separation function of reflecting the fluorescence YL, which has a different wavelength band from the blue light E, regardless of its polarization state.

[0016] The optical element 22 transmits the light ray Ep, which is the P-polarized component of the blue light ray E distributed by the first phase difference element 21, and emits it to the wavelength conversion element 25, and reflects the light ray Es, which is the S-polarized component of the blue light ray E, and emits it to the diffusion element 26. The light ray Ep, which is the P-polarized component emitted from the optical element 22, is incident on the first light-collecting optical system 23. The first light-collecting optical system 23 collects the light ray Ep as excitation light toward the phosphor 25a of the wavelength conversion element 25. The first light-collecting optical system 23 is composed of, for example, a pair of lenses 23a and 23b.

[0017] The wavelength conversion element 25 has a reflective layer 25b, a phosphor 25a provided on the light incident side of the reflective layer 25b, and a substrate 25c supporting the phosphor 25a. That is, the wavelength conversion element 25 of this embodiment is a fixed type wavelength conversion element in which the incident area of ​​the light Ep does not change over time.

[0018] The phosphor 25a converts the light beam Ep, which is the excitation light, into fluorescence YL having a wavelength band different from the first wavelength band. The phosphor 25a includes a ceramic phosphor made of a polycrystalline phosphor that converts the wavelength of the light beam Ep into fluorescence YL. The wavelength band of the fluorescence YL is, for example, a yellow wavelength band of 490 to 750 nm. In other words, the fluorescence YL is yellow fluorescence containing a red light component and a green light component.

[0019] Specifically, the material of the phosphor 25a includes, for example, an yttrium aluminum garnet (YAG) phosphor. For example, in the case of YAG:Ce containing cerium (Ce) as an activator, the material of the phosphor 25a may be a material obtained by mixing raw material powders containing constituent elements such as Y2O3, Al2O3, and CeO3 and reacting them in a solid state, Y-Al-O amorphous particles obtained by a wet method such as a coprecipitation method or a sol-gel method, or YAG particles obtained by a gas phase method such as a spray drying method, a flame pyrolysis method, or a thermal plasma method.

[0020] The reflective layer 25b reflects a component of the fluorescence YL generated by the phosphor 25a that travels toward the substrate 25c. A heat dissipation member such as a heat sink may be disposed on the surface of the substrate 25c opposite to the surface supporting the phosphor 25a.

[0021] Of the fluorescence YL generated by the phosphor 25a, a part of the fluorescence YL is reflected by the reflective layer 25b and emitted to the outside of the phosphor 25a. Also, of the fluorescence YL generated by the phosphor 25a, another part of the fluorescence YL is emitted to the outside of the phosphor 25a without passing through the reflective layer 25b. In this manner, the fluorescence YL is emitted from the wavelength conversion element 25.

[0022] The fluorescence YL emitted from the phosphor 25a is unpolarized light. The fluorescence YL passes through the first light collecting optical system 23 and then enters the optical element 22. The fluorescence YL is reflected by the optical element 22 and travels toward the lens integrator 31.

[0023] On the other hand, a light ray Es, which is an S-polarized component of the blue light ray E emitted from the optical element 22, is incident on the second phase difference element 27. The second phase difference element 27 is composed of a quarter-wave plate arranged in the optical path between the optical element 22 and the diffusion element 26. Therefore, the S-polarized light ray Es emitted from the optical element 22 is converted by the second phase difference element 27 into, for example, right-handed circularly polarized blue light Bc1, and then is incident on the second focusing optical system 24. The second focusing optical system 24 is composed of, for example, a pair of lenses 24a and 24b, and causes the blue light Bc1 to be incident on the diffusion element 26 in a focused state.

[0024] The diffusion element 26 diffuses and reflects the blue light Bc1 emitted from the second light collecting optical system 24 toward the optical element 22. It is preferable to use a diffusion element 26 that reflects the blue light Bc1 in a Lambertian manner without disturbing the polarization state. Note that the diffusion element 26 may be configured to rotate a circular diffusion reflector.

[0025] Hereinafter, the light diffusely reflected by the diffusion element 26 is referred to as blue light Bc2. According to this embodiment, blue light Bc2 having a substantially uniform illuminance distribution is obtained by diffusing and reflecting blue light Bc1. For example, right-handed circularly polarized blue light Bc1 is reflected as left-handed circularly polarized blue light Bc2. The blue light Bc2 is converted into parallel light by the second focusing optical system 24 and then enters the second phase difference element 27 again.

[0026] The left-handed circularly polarized blue light Bc2 is converted into P-polarized blue light B by the second phase difference element 27. The P-polarized blue light B passes through the optical element 22 and is emitted towards the lens integrator 31.

[0027] In this embodiment, the optical element 22 emits, in the same direction, the blue light B incident from the diffusion element 26 and the fluorescence YL incident from the wavelength conversion element 25. Therefore, the blue light B and the fluorescence YL are combined with each other by the optical element 22 to generate white illumination light WL.

[0028] The illumination light WL combined by the optical element 22 is incident on the lens integrator 31. The lens integrator 31 has a first multi-lens 31a and a second multi-lens 31b. The first multi-lens 31a has a plurality of first small lenses 31am for splitting the illumination light WL into a plurality of partial ray bundles.

[0029] The surface of the first small lenses 31am, which is the lens surface of the first multi-lens 31a, and the image forming areas of the light modulation devices 140R, 140G, and 140B are conjugate with each other. Therefore, the shape of each of the first small lenses 31am is approximately similar to the shape of the image forming areas of the light modulation devices 140R, 140G, and 140B. As a result, each of the partial light beams emitted from the first multi-lens 31a is efficiently incident on the image forming areas of the light modulation devices 140R, 140G, and 140B.

[0030] The second multi-lens 31b has a plurality of second small lenses 31bm corresponding to the plurality of first small lenses 31am of the first multi-lens 31a. The second multi-lens 31b, together with the superimposing lens 33, forms an image of each of the first small lenses 31am of the first multi-lens 31a in the vicinity of the image forming area of ​​each of the light modulation devices 140R, 140G, and 140B.

[0031] The illumination light WL transmitted through the lens integrator 31 is incident on the polarization conversion element 32 . The polarization conversion element 32 is configured by arranging a polarization separation film and a retardation plate (1 / 2 retardation plate) in an array. The polarization conversion element 32 converts the illumination light WL into a predetermined polarized component. More specifically, the polarization conversion element 32 converts the polarization direction of the red light LR and the green light LG separated from the illumination light WL as described later into a polarization direction that transmits through an incident-side polarizing plate arranged on the light incident side of the optical modulation devices 140R and 140G described later. The polarization conversion element 32 also converts the polarization direction of the blue light LB separated from the illumination light WL into a first polarized component that is reflected by a first polarizing element 135 arranged in front of the optical modulation device 140B described later. By aligning the polarization direction of the illumination light WL using the polarization conversion element 32 in this manner, the loss that occurs when the illumination light WL is polarized and separated can be reduced, as described below, thereby making it possible to further increase the light utilization efficiency.

[0032] The illumination light WL transmitted through the polarization conversion element 32 is incident on the superimposing lens 33. The superimposing lens 33 cooperates with the lens integrator 31 to homogenize the illuminance distribution of the illumination light WL in the illuminated area.

[0033] Returning to Fig. 1, the color separation optical system 130 separates the illumination light WL into red light LR, green light LG, and blue light LB. The red light LR and green light LG are each separated from the yellow fluorescence YL contained in the illumination light WL. The blue light LB corresponds to the blue light B contained in the illumination light WL.

[0034] The color separation optical system 130 includes a first dichroic mirror 131, a first mirror 132, a second dichroic mirror 133, a second mirror 134, a first polarizing element 135, a first relay lens 136, and a second relay lens 137.

[0035] The first dichroic mirror 131 is disposed on the optical path of the illumination light WL emitted from the illumination device 120, and separates the incident illumination light WL into red light LR, green light LG, and blue light LB. The first dichroic mirror 131 transmits the red light LR and reflects the green light LG and blue light LB. The first mirror 132 is disposed on the optical path of the red light LR emitted from the first dichroic mirror 131, and reflects the red light LR toward the optical modulation device 140R.

[0036] The second dichroic mirror 133 is disposed on a common optical path of the green light LG and the blue light LB emitted from the first dichroic mirror 131, and separates the green light LG from the blue light LB. The second dichroic mirror 133 transmits the blue light LB and reflects the green light LG. The green light LG enters the light modulation device 140G from the second dichroic mirror 133.

[0037] The second mirror 134 is disposed on the optical path of the blue light LB emitted from the second dichroic mirror 133, and reflects the blue light LB toward the first polarizing element 135. The first polarizing element 135 reflects a predetermined polarized component of the blue light LB and causes it to enter the light modulation device 140B.

[0038] The blue light LB corresponds to laser light in the blue wavelength band of the illumination light WL, which is light emitted from the light source 2. That is, the blue light LB in this embodiment corresponds to "first laser light in a first wavelength band" in the claims.

[0039] The first polarizing element 135 of this embodiment is made of a dielectric multilayer film, and separates the incident blue light LB into an S-polarized component and a P-polarized component for the transmissive liquid crystal panel 40B of the light modulation device 140B. The first polarizing element 135 is disposed at an angle of 45° with respect to the principal ray of the incident blue light LB. With this configuration, it is easy to control the exit direction of the S-polarized component separated by the first polarizing element 135, so that the separated light can be efficiently incident on the light modulation device 140B. In the following description, unless otherwise specified, the notations of S-polarized light and P-polarized light in the blue light LB refer to the polarization direction with respect to the transmissive liquid crystal panel 40B.

[0040] FIG. 3 is a graph showing the spectral characteristics of the first polarizing element 135. As shown in FIG. 3, the first polarizing element 135 has the spectral characteristics of transmitting P-polarized light of blue light LB in the blue wavelength band (first wavelength band) of 445 nm to 460 nm and reflecting S-polarized light of the blue light LB.

[0041] Here, the blue light LB made of laser light emitted from the illumination device 120 is emitted as S-polarized light, but since it passes through multiple optical components before entering the first polarizing element 135, there is a slight disturbance in the polarization direction. Therefore, although the blue light LB is mainly composed of S-polarized light, it also contains a small amount of P-polarized light.

[0042] The first polarizing element 135 transmits blue light LBp, which is a P-polarized component of the incident blue light LB, and reflects blue light LBs, which is an S-polarized component of the blue light LB. Note that the amount of blue light LBp transmitted through the first polarizing element 135 is very small, and is blocked by a light blocking member (not shown), so it does not become a cause of stray light.

[0043] As a result, the first polarizing element 135 separates the blue light LBs, which is the S-polarized component that is the first polarized component of the blue light LB, and causes it to be incident on the optical modulation device 140B. That is, in this embodiment, the blue light LBs corresponds to the "first polarized component of the first laser light" in the claims.

[0044] The first relay lens 136 is disposed on the optical path of the blue light LB between the second dichroic mirror 133 and the second mirror 134. The second relay lens 137 is disposed on the optical path of the blue light LB between the second mirror 134 and the first polarizing element 135. By disposing the first relay lens 136 and the second relay lens 137, the optical loss of the blue light LB is compensated for. The optical loss of the blue light LB is caused by the optical path length of the blue light LB from the first dichroic mirror 131 to the optical modulation device 140B being longer than the optical path length of the red light LR from the first dichroic mirror 131 to the optical modulation device 140R and the optical path length of the green light LG from the first dichroic mirror 131 to the optical modulation device 140G.

[0045] A field lens 42R is disposed on the optical path of the red light LR between the first mirror 132 and the optical modulation device 140R. The field lens 42R allows the red light LR to be efficiently incident on the optical modulation device 140R. A field lens 42G is disposed on the optical path of the green light LG between the second dichroic mirror 133 and the optical modulation device 140G. The field lens 42G allows the green light LG to be efficiently incident on the optical modulation device 140G. A field lens 42B is disposed on the optical path of the blue light LB between the first polarizing element 135 and the optical modulation device 140B. The blue light LB is efficiently incident on the optical modulation device 140B by the field lens 42B.

[0046] The light modulation device 140 R is disposed on the optical path of the red light LR that is reflected by the second dichroic mirror 133 and emerges from the second dichroic mirror 133 . The light modulation device 140R is composed of a transmissive liquid crystal panel 40R, an incident side polarizing plate 43R, and an exit side polarizing plate 41R. The transmissive liquid crystal panel 40R modulates the incident red light LR in accordance with image information input from an image input device (not shown) to form and emit red image light. The image input device may be, for example, a personal computer or a portable terminal device. The incident-side polarizing plate 43R is provided on the light incident side of the transmissive liquid crystal panel 40R. As described above, the red light LR is light obtained by separating the red wavelength band of the fluorescence YL, which is unpolarized, and is therefore unpolarized light like the fluorescence YL. For this reason, the incident-side polarizing plate 43R transmits a predetermined linearly polarized component contained in the red light LR and allows it to enter the transmissive liquid crystal panel 40R. The exit side polarizing plate 41R is provided on the light exit side of the transmissive liquid crystal panel 40R. The entrance side polarizing plate 43R and the exit side polarizing plate 41R are arranged so that their polarization axes are perpendicular to each other.

[0047] The light modulation device 140G is disposed on the optical path of the green light LG that is reflected by the second mirror 133 and emitted from the second mirror 133. The light modulation device 140G is composed of a transmissive liquid crystal panel 40G, an incident side polarizing plate 43G, and an exit side polarizing plate 41G. The transmissive liquid crystal panel 40G modulates the incident green light LG in accordance with image information input from an image input device (not shown) to form and emit green image light. The incident-side polarizing plate 43G is provided on the light incident side of the transmissive liquid crystal panel 40G. As described above, the green light LG is light obtained by separating the green wavelength band of the fluorescence YL, which is unpolarized, and is therefore unpolarized light like the fluorescence YL. Therefore, the incident-side polarizing plate 43G transmits a predetermined linearly polarized component contained in the green light LG and allows it to enter the transmissive liquid crystal panel 40G. The exit side polarizing plate 41G is provided on the light exit side of the transmissive liquid crystal panel 40G. The entrance side polarizing plate 43G and the exit side polarizing plate 41G are arranged so that their polarization axes are perpendicular to each other.

[0048] The light modulation device 140B is disposed on the optical path of the blue light LBs separated by the first polarizing element 135. The light modulation device 140B is composed of a transmissive liquid crystal panel 40B and an exit-side polarizing plate 41 B. The transmissive liquid crystal panel 40B modulates the incident blue light LBs in accordance with image information input from an image input device (not shown), forms blue image light, and emits it.

[0049] Here, a case will be described where, instead of the first polarizing element 135, the blue light LB is reflected by a mirror and made to enter the transmissive liquid crystal panel 40B. In this case, an incident-side polarizing plate is required to remove the P-polarized light contained in the blue light LB. Since the blue light LBs in this embodiment is laser light, it is preferable to use a polarizing plate with a wire grid structure, which has excellent light resistance, as the incident-side polarizing plate. However, when a polarizing plate with a wire grid structure transmits light of a predetermined polarization direction, loss occurs due to interfacial reflection on the surface, which causes a problem of reduced light utilization efficiency.

[0050] In contrast, in the present embodiment, the blue light LBs incident on the light modulation device 140B is reflected by the first polarizing element 135 and separated from the blue light LB, and is then incident on the transmissive liquid crystal panel 40B as linearly polarized light. Since the blue light LBs is separated by being reflected from the blue light LB in this manner, the separated blue light LBs can be easily guided to the light modulation device 140B. This makes it easier to layout each component.

[0051] In the projector 100 of this embodiment, the first polarizing element 135 functions as a light incident side polarizing plate for the transmissive liquid crystal panel 40B, so there is no need to provide a separate polarizing plate on the light incident side of the transmissive liquid crystal panel 40G. In other words, unlike the other light modulation devices 140R and 140G, the light modulation device 140B of this embodiment does not include an incident side polarizing plate, and only includes an exit side polarizing plate 41B on the light exit side of the transmissive liquid crystal panel 40B. The polarization axis of the exit side polarizing plate 41B is set to be perpendicular to the polarization axis of the blue light LBs incident from the first polarizing element 135. Since the first polarizing element 135 is composed of a dielectric multilayer film as described above, losses such as interfacial reflection that occur when separating blue light LBs from blue light LB are reduced compared to the case where a polarizing plate with a wire grid structure is used, and the light utilization efficiency of the blue light LB can be improved.

[0052] The color synthesis optical system 150 is disposed across the optical path of the red image light emitted from the light modulation device 140R, the optical path of the green image light emitted from the light modulation device 140G, and the optical path of the blue image light emitted from the light modulation device 140B. When viewed from the top or side as shown in FIG. 1, the synthesis position of the color light in the color synthesis optical system 150 overlaps with the intersection of the optical path of the red image light, the optical path of the green image light, and the optical path of the blue image light. In the color synthesis optical system 150, the red image light, the green image light, and the blue image light are synthesized with each other to form color image light. The color synthesis optical system 150 emits color image light. For example, a cross dichroic prism is used for the color synthesis optical system 150.

[0053] The projection optical system 160 is disposed on the optical path of the color image light emitted from the color synthesis optical system 150. The color image light emitted from the color synthesis optical system 150 corresponds to the light modulated by the light modulation devices 140R, 140G, and 140B. The projection optical system 160 enlarges and projects the color image light emitted from and incident on the color synthesis optical system 150 toward the screen SCR. The color image light enlarged and projected from the projection optical system 160 is displayed as a color image on a display surface of the screen SCR facing the emission surface of the projection optical system 160.

[0054] The projection optical system 160 is composed of, for example, a plurality of optical lenses, but may be composed of a single optical lens. The optical lens includes various lenses, such as a plano-convex lens, a biconvex lens, a meniscus lens, an aspheric lens, a rod lens, and a free curved lens.

[0055] As described above, the projector 100 of this embodiment includes a light source 2 that emits illumination light WL including blue light LB in the blue wavelength band, a first polarizing element 135 formed of a dielectric multilayer film that separates blue light LBs that is an S-polarized component from the incident blue light LB, a transmissive liquid crystal panel 40B that modulates the blue light LBs separated by the first polarizing element 135, and a projection optical system 160 that projects the light modulated by the transmissive liquid crystal panel 40B.

[0056] According to the projector 100 of this embodiment, the blue light LBs polarized and separated from the blue light LB by the first polarizing element 135 made of a dielectric multilayer film is incident on the transmissive liquid crystal panel 40B, so that the light utilization efficiency of the blue light LB can be improved. Therefore, the transmissive liquid crystal panel 40B can modulate bright image light. Therefore, the projector 100 of this embodiment can project a bright image by efficiently utilizing the illumination light WL emitted from the illumination device 120.

[0057] Second embodiment Next, a projector according to a second embodiment will be described. The difference between this embodiment and the first embodiment is the layout of the lighting device and the first polarizing element, etc., and the configuration of each component according to the difference in layout, and the other configurations are common. Therefore, the configuration related to the difference in layout will be described below, and the same reference numerals will be used for the components common to the above embodiment, and detailed description will be omitted.

[0058] FIG. 4 is a diagram showing a schematic configuration of a projector 102 according to the present embodiment. 4, the projector 102 of this embodiment includes an illumination device 120, a color separation optical system 230, light modulation devices 140R, 140G, and 140B, a color synthesis optical system 150, and a projection optical system 160. In the projector 102 of this embodiment, the positions of the light modulation devices 140R, 140G, and 140B relative to the color synthesis optical system 150 are interchanged with respect to the positional relationship in the projector 100 of the first embodiment. In addition, the projector 102 of this embodiment has a different incident direction of illumination light WL relative to the color separation optical system 230 compared to the projector 100 of the first embodiment.

[0059] The color separation optical system 230 of this embodiment includes a first polarizing element 135, a first mirror 232, a first dichroic mirror 233, a third dichroic mirror 234, a second mirror 235, a first relay lens 236, and a second relay lens 237.

[0060] The first polarizing element 135 is disposed on the optical path of the illumination light WL emitted from the lighting device 120, and separates the incident illumination light WL into red light LR, green light LG, and blue light LB. Specifically, the first polarizing element 135 transmits the green light LG and red light LR of the illumination light WL. In addition, with regard to the blue light LB, the first polarizing element 135 transmits blue light LBp, which is a P-polarized component, and reflects blue light LBs, which is an S-polarized component.

[0061] The first mirror 232 is disposed on the optical path of the blue light LBs reflected by the first polarizing element 135, and reflects the blue light LBs toward the light modulation device 140B.

[0062] The first dichroic mirror 233 is disposed on the optical path of the blue light LBp, red light LR, and green light LG transmitted through the first polarizing element 135, and separates the blue light LBp, red light LR, and green light LG. The first dichroic mirror 233 transmits the blue light LBp and red light LR, and reflects the green light LG. The green light LG is incident on the optical modulation device 140G from the first dichroic mirror 233.

[0063] The third dichroic mirror 234 is disposed on the optical path of the blue light LBp and the red light LR emitted from the first dichroic mirror 233, and separates the blue light LBp from the red light LR. The third dichroic mirror 234 transmits the blue light LBp and reflects the red light LR. Note that the amount of blue light LBp transmitted through the third dichroic mirror 234 is very small, and is blocked by a light blocking member (not shown), so it does not become a cause of stray light.

[0064] The second mirror 235 is disposed on the optical path of the red light LR reflected by the third dichroic mirror 234, and reflects the red light LR toward the optical modulation device 140R. The first relay lens 236 is disposed on the optical path of the red light LR between the first dichroic mirror 233 and the third dichroic mirror 234. The second relay lens 237 is disposed on the optical path of the red light LR between the third dichroic mirror 234 and the second mirror 235. By disposing the first relay lens 236 and the second relay lens 237, optical loss caused by the difference in optical path length of the red light LR is compensated for.

[0065] In the projector 102 of this embodiment as well, the blue light LBs polarized and separated from the blue light LB by the first polarizing element 135 made of a dielectric multilayer film is made incident on the transmissive liquid crystal panel 40B, so that the light utilization efficiency of the blue light LB can be improved. Therefore, in the projector 102 of this embodiment as well, the illumination light WL is efficiently utilized to project a bright image.

[0066] 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 illumination device and the color separation optical system, and the other configurations are the same. Therefore, the following mainly describes the configuration of the illumination device and the color separation optical system, and the same reference numerals are used for the members common to the above embodiments, and detailed description is omitted.

[0067] FIG. 5 is a diagram showing a schematic configuration of a projector 103 according to the present embodiment. 5, the projector 103 of this embodiment includes an illumination device 320, a color separation optical system 330, light modulation devices 140R, 140G, and 140B, a color synthesis optical system 150, and a projection optical system 160. The positional relationship of the light modulation devices 140R, 140G, and 140B with respect to the color synthesis optical system 150 in the projector 103 of this embodiment is equal to the positional relationship in the projector 102 of the second embodiment. Note that some of the components of the color separation optical system 330 are common to some of the components of the color separation optical system 230 of the second embodiment, and therefore the common components are denoted by the same reference numerals and description thereof will be omitted.

[0068] As shown in FIG. 5, the illumination device 320 includes a light source 3, a lens integrator 31, a polarization conversion element 32, and a superimposing lens 33. The light source 3 has a light-emitting element 20a, a first phase difference element 21, a first optical element 122, a first focusing optical system 23, a second focusing optical system 24, a wavelength conversion element 29, a diffusion element 26, a second phase difference element 27, another light-emitting element 50, a first focusing lens 51, a diffusion element 52, a second focusing lens 53, and a second optical element 123.

[0069] The light emitting element 20a, the first phase difference element 21, the first optical element 122, the first light collecting optical system 23, and the wavelength conversion element 25 are arranged in sequence on the optical axis ax1. The diffusion element 26, the second focusing optical system 24, the second phase difference element 27, the first optical element 122, the second optical element 123, the lens integrator 31, the polarization conversion element 32, and the superimposing lens 33 are arranged in sequence on the illumination optical axis ax2. The optical axis ax1 and the illumination optical axis ax2 are in the same plane and are perpendicular to each other. Further, the other light-emitting element 50, the first condenser lens 51, the diffusion element 52, the second condenser lens 53, and the second optical element 123 are sequentially arranged in a line on the optical axis ax3. The optical axis ax3 is the optical axis of the other light-emitting element 50, and is in the same plane as the optical axis ax1 and the illumination optical axis ax2, and is an axis parallel to the optical axis ax1.

[0070] The first optical element 122 is disposed to form an angle of 45° with respect to the optical axis ax1 and the illumination optical axis ax2. The first optical element 122 has a polarization separation function that separates the blue light ray E into a light ray Es having an S-polarized component and a light ray Ep having a P-polarized component with respect to the first optical element 122. The first optical element 122 has a color separation function that reflects the fluorescence GL, which has a different wavelength band from the blue light ray E, regardless of its polarization state.

[0071] The wavelength conversion element 29 has a reflective layer 29b, a phosphor 29a, and a substrate 29c. The phosphor 29a converts the light Ep, which is excitation light, into fluorescence GL having a second wavelength band different from the first wavelength band. The phosphor 29a contains a ceramic phosphor made of a polycrystalline phosphor that converts the wavelength of the light Ep into fluorescence GL. The second wavelength band of the fluorescence GL is, for example, a green wavelength band of 500 to 570 nm. In other words, the fluorescence GL is green fluorescence containing a green light component.

[0072] As such a green phosphor 29a, for example, Lu3Al5O 12 :Ce 3+ Phosphor, Y3O4:Eu 2+ Phosphor, (Ba,Sr)2SiO4:Eu2+ Ba3Si6O phosphor 12 N2:Eu 2+ Phosphor of the (Si,Al)6(O,N)8:Eu system 2+ Phosphor materials such as ZnO-based phosphors are used.

[0073] The reflection layer 29b reflects a component of the fluorescence GL generated by the phosphor 29a that travels toward the substrate 29c. A part of the fluorescence GL generated by the phosphor 29a is reflected by the reflection layer 29b and emitted to the outside of the phosphor 29a. Another part of the fluorescence GL generated by the phosphor 29a is emitted to the outside of the phosphor 29a without passing through the reflection layer 29b. In this manner, the fluorescence GL is emitted from the wavelength conversion element 29. After passing through the first focusing optical system 23, the fluorescence GL is incident on the first optical element 122. The fluorescence GL is reflected by the first optical element 122 and travels toward the second optical element 123.

[0074] The first optical element 122 emits the blue light B incident thereon from the diffusion element 26 and the fluorescence GL incident thereon from the wavelength conversion element 29 toward the second optical element 123.

[0075] The other light emitting element 50 is composed of a semiconductor laser. The other light emitting element 50 emits a red light beam ER in a red wavelength band, for example, having a wavelength band of 640 nm to 650 nm. Note that, as the other light emitting element 50, a semiconductor laser that emits a laser beam in a wavelength band other than the above may also be used. Note that the number of the other light emitting elements 50 is not particularly limited and may be one or more.

[0076] The red light ER emitted from the other light-emitting element 50 is collected by the first collecting lens 51 and enters the diffusing element 52, where it is diffused and collimated by the second collecting lens 53. In this manner, the second collecting lens 53 emits the red light R consisting of parallel light toward the second optical element 123.

[0077] The second optical element 123 is disposed to form an angle of 45° with respect to the optical axis ax3 and the illumination optical axis ax2. The second optical element 123 is composed of a dichroic mirror having optical properties of reflecting red light R and transmitting fluorescence GL and blue light B incident from the first optical element 122. The second optical element 123 emits red light R, fluorescence GL, and blue light B in the same direction. Therefore, the red light R, fluorescence GL, and blue light B are combined together by the second optical element 123 to generate white illumination light WL1.

[0078] The illumination light WL1 passes through the lens integrator 31, the polarization conversion element 32, and the superimposing lens 33 and enters the color separation optical system 330. Note that a description of the actions of the lens integrator 31, the polarization conversion element 32, and the superimposing lens 33 on the illumination light WL1 will be omitted.

[0079] The color separation optical system 330 separates the illumination light WL1 into red light LR, green light LG, and blue light LB. The red light LR corresponds to the red light R contained in the illumination light WL1, the green light LG corresponds to the green fluorescence GL contained in the illumination light WL1, and the blue light LB corresponds to the blue light B contained in the illumination light WL1. In other words, the green light LG in this embodiment corresponds to the "second light in the second wavelength band" in the claims, and the red light LR in this embodiment corresponds to the "second laser light in the fourth wavelength band" in the claims.

[0080] The color separation optical system 330 includes a first polarizing element 135, a first mirror 232, a first dichroic mirror 233, a third dichroic mirror 234, a second polarizing element 335, a first relay lens 236, and a second relay lens 237.

[0081] The first polarizing element 135 is disposed on the optical path of the illumination light WL1 emitted from the lighting device 320, and separates the incident illumination light WL1 into red light LR, green light LG, and blue light LB. Specifically, the first polarizing element 135 transmits the green light LG and red light LR of the illumination light WL1. In addition, with regard to the blue light LB, the first polarizing element 135 transmits blue light LBp, which is a P-polarized component, and reflects blue light LBs, which is an S-polarized component. In this manner, the first polarizing element 135 transmits the green light LG and the red light LR, thereby separating the green light LG and the red light LR from the blue light LBs.

[0082] The first mirror 232 is disposed on the optical path of the blue light LBs reflected by the first polarizing element 135, and reflects the blue light LBs toward the light modulation device 140B.

[0083] The first dichroic mirror 233 separates the blue light LBp, the red light LR, and the green light LG transmitted through the first polarizing element 135 into the blue light LBp, the red light LR, and the green light LG. The first dichroic mirror 233 transmits the blue light LBp and the red light LR, and reflects the green light LG. That is, the first dichroic mirror 233 reflects the green light LG and transmits the blue light LBp and the red light LR, thereby separating the green light LG and the red light LR. In this way, the green light LG is incident on the light modulation device 140G from the first dichroic mirror 233. That is, the first dichroic mirror 233 in this embodiment corresponds to the "light separation element" in the claims.

[0084] The third dichroic mirror 234 separates the blue light LBp and the red light LR emitted from the first dichroic mirror 233. The third dichroic mirror 234 transmits the blue light LBp and reflects the red light LR. Note that the amount of blue light LBp transmitted through the third dichroic mirror 234 is very small, and is blocked by a light blocking member (not shown), so it does not become a cause of stray light.

[0085] The second polarizing element 335 is disposed on the optical path of the red light LR reflected by the third dichroic mirror 234. The second polarizing element 335 reflects a predetermined polarized component of the red light LR and causes it to enter the light modulation device 140R.

[0086] The second polarizing element 335 of this embodiment is made of a dielectric multilayer film, and separates the incident red light LR into an S-polarized component and a P-polarized component for the transmissive liquid crystal panel 40R of the light modulation device 140R. The second polarizing element 335 is disposed at an angle of 45° with respect to the principal ray of the incident red light LR. With this configuration, it is easy to control the exit direction of the S-polarized component separated by the second polarizing element 335, so that the separated light can be efficiently incident on the light modulation device 140R. In the following description, unless otherwise specified, the notations S-polarized light and P-polarized light for the red light LR refer to the polarization direction with respect to the transmissive liquid crystal panel 40R.

[0087] FIG. 6 is a graph showing the spectral characteristics of the second polarizing element 335. As shown in FIG. 6, the second polarizing element 335 has the spectral characteristics of transmitting P-polarized light of red light LR in a red wavelength band (fourth wavelength band) of 640 nm to 650 nm and reflecting S-polarized light of red light LR.

[0088] Here, the red light LR composed of laser light emitted from the illumination device 320 is emitted as S-polarized light, but since it passes through multiple optical components before entering the second polarizing element 335, there is a slight disturbance in the polarization direction. Therefore, although the red light LR is mainly composed of S-polarized light, it also contains a small amount of P-polarized light.

[0089] The second polarizing element 335 transmits red light LRp, which is a P-polarized component of the incident red light LR, and reflects red light LRs, which is an S-polarized component of the red light LR. Note that the amount of red light LRp transmitted through the second polarizing element 335 is very small, and is blocked by a light blocking member (not shown), so it does not become a cause of stray light.

[0090] The first relay lens 236 is disposed on the optical path of the red light LR between the first dichroic mirror 233 and the third dichroic mirror 234. The second relay lens 237 is disposed on the optical path of the red light LR between the third dichroic mirror 234 and the second polarizing element 335. By disposing the first relay lens 236 and the second relay lens 237, optical loss caused by the difference in optical path length of the red light LR is compensated for.

[0091] In this way, the second polarizing element 335 separates the red light LRs, which is the S-polarized component that is the first polarization component of the red light LR, and causes it to enter the transmissive liquid crystal panel 40R of the light modulation device 140R. The transmissive liquid crystal panel 40R of this embodiment corresponds to the "second transmissive liquid crystal panel" in the claims.

[0092] The light modulation device 140R of this embodiment is composed of a transmissive liquid crystal panel 40R and an exit side polarizing plate 41R. Since the second polarizing element 335 functions as a light incident side polarizing plate of the transmissive liquid crystal panel 40R, it is not necessary to separately provide a polarizing plate on the light incident side of the transmissive liquid crystal panel 40R. In other words, like the light modulation device 140B, the light modulation device 140R of this embodiment does not include an incident side polarizing plate, and only includes an exit side polarizing plate 41B on the light exit side of the transmissive liquid crystal panel 40R. The polarization axis of the exit side polarizing plate 41R is set to be perpendicular to the polarization axis of the red light LRs incident from the second polarizing element 335. Since the second polarizing element 335 is composed of a dielectric multilayer film as described above, losses such as interfacial reflection that occur when separating the red light LR from the red light LRs are reduced compared to the case where a polarizing plate with a wire grid structure is used, and the light utilization efficiency of the red light LR can be improved.

[0093] According to the projector 103 of the present embodiment, in addition to the action of the first polarizing element 135, the second polarizing element 335 made of a dielectric multilayer film can polarized and separated red light LRs from the red light LR and cause it to enter the transmissive liquid crystal panel 40R. This can improve the light utilization efficiency of the blue light LB and the red light LR. Thus, the projector 103 of the present embodiment can project a brighter image by efficiently utilizing the illumination light WL1 emitted from the illumination device 320.

[0094] (Fourth embodiment) Next, a projector according to a fourth embodiment will be described. The difference between this embodiment and the first embodiment is the configuration of the illumination device and the color separation optical system, and the other configurations are the same. Therefore, the following mainly describes the configuration of the illumination device and the color separation optical system, and the same reference numerals are used for the members common to the above embodiments, and detailed description is omitted.

[0095] FIG. 7 is a diagram showing a schematic configuration of a projector 103 according to the present embodiment. 7, the projector 104 of this embodiment includes an illumination device 420, a color separation optical system 430, light modulation devices 140R, 140G, and 140B, a color synthesis optical system 150, and a projection optical system 160. The positional relationship of the light modulation devices 140R, 140G, and 140B with respect to the color synthesis optical system 150 in the projector 104 of this embodiment is equal to the positional relationship in the projector 102 of the second embodiment. Note that some of the components of the color separation optical system 430 are common to some of the components of the color separation optical system 230 of the second embodiment, and therefore the common components are denoted by the same reference numerals and description thereof will be omitted.

[0096] 7, the illumination device 420 includes a light source 4, a lens integrator 31, a polarization conversion element 32, and a superimposing lens 33. The illumination device 420 of this embodiment differs from the above-described embodiments in that it emits illumination light consisting of laser light.

[0097] The light source 4 of the present embodiment has a light-emitting element section 60, a first condensing lens 61, a diffusion element 62, and a second condensing lens 63. The light-emitting element section 60, the first condensing lens 61, the diffusion element 62, and the second condensing lens 63 are sequentially arranged on the optical axis ax4 of the light-emitting element section 60.

[0098] The light emitting element section 60 has a red light emitting section 60R, a green light emitting section 60G, and a blue light emitting section 60B. The red light emitting section 60R is composed of a semiconductor laser that emits red laser light Rr in a red wavelength band having a wavelength band of, for example, 640 nm to 650 nm. The green light emitting section 60G is composed of a semiconductor laser that emits green laser light Gg in a green wavelength band having a wavelength band of, for example, 520 nm to 545 nm. The blue light emitting section 60B is composed of a semiconductor laser that emits blue laser light Bb in a blue wavelength band having a wavelength band of, for example, 445 nm to 460 nm. The light emitting element section 60 of this embodiment has a unit structure in which the red light emitting section 60R, the green light emitting section 60G, and the blue light emitting section 60B are mounted on the same substrate. Based on this configuration, the light emitting element section 60 is adapted to emit white illumination light WL2 containing red laser light Rr, green laser light Gg, and blue laser light Bb.

[0099] The illumination light WL2 emitted from the light-emitting element section 60 is collected by the first collecting lens 61 and enters the diffusing element 62, where it is diffused and collimated by the second collecting lens 63. In this manner, the second collecting lens 63 emits the illumination light WL2 consisting of parallel light toward the lens integrator 31.

[0100] The illumination light WL2 passes through the lens integrator 31, the polarization conversion element 32, and the superimposing lens 33 and enters the color separation optical system 330. Note that a description of the actions of the lens integrator 31, the polarization conversion element 32, and the superimposing lens 33 on the illumination light WL2 will be omitted.

[0101] The color separation optical system 430 separates the illumination light WL2 into red light LR, green light LG, and blue light LB. The red light LR corresponds to the red laser light Rr contained in the illumination light WL2, the green light LG corresponds to the green laser light Gg contained in the illumination light WL2, and the blue light LB corresponds to the blue laser light Bb contained in the illumination light WL2. In other words, the blue light LB of this embodiment corresponds to the "first laser light in the first wavelength band" in the claims, the green light LG of this embodiment corresponds to the "second laser light in the third wavelength band" in the claims, and the red light LR of this embodiment corresponds to the "third laser light in the fourth wavelength band" in the claims.

[0102] The color separation optical system 430 includes a first dichroic mirror 431, a first polarizing element 432, a second polarizing element 433, a second dichroic mirror 434, a third polarizing element 435, a first relay lens 236, and a second relay lens 237.

[0103] The first dichroic mirror 431 is disposed on the optical path of the illumination light WL2 emitted from the illumination device 420, and separates the incident illumination light WL2 into red light LR, green light LG, and blue light LB. Specifically, the first dichroic mirror 431 reflects the blue light LB of the illumination light WL2 and transmits the green light LG and red light LR. In other words, the first dichroic mirror 431 in this embodiment corresponds to a "light separating element" in the claims.

[0104] The first polarizing element 432 is disposed on the optical path of the blue light LB reflected by the first dichroic mirror 431. The first polarizing element 432 of this embodiment is made of a dielectric multilayer film, and separates the incident blue light LB into an S-polarized component and a P-polarized component for the transmissive liquid crystal panel 40B of the light modulation device 140B. The first polarizing element 432 of this embodiment has the same spectral characteristics as the first polarizing element 135 of the projector 100 of the first embodiment. That is, the first polarizing element 432 transmits blue light LBp, which is the P-polarized component, and reflects blue light LBs, which is the S-polarized component, of the blue light LB.

[0105] The first polarizing element 432 is disposed so as to form an angle of 45° with respect to the principal ray of the incident blue light LB. With this configuration, it is easy to control the exit direction of the S-polarized component separated by the first polarizing element 432, so that the separated blue light LBs can be efficiently incident on the light modulation device 140B.

[0106] The second polarizing element 433 is disposed on the optical path of the red light LR and the green light LG transmitted through the first dichroic mirror 431. The second polarizing element 433 transmits the red light LR and reflects the green light LG. The second polarizing element 433 reflects a predetermined polarized component of the green light LG and causes it to enter the light modulation device 140G.

[0107] The second polarizing element 433 of this embodiment is made of a dielectric multilayer film, and separates the incident green light LG into an S-polarized component and a P-polarized component for the transmissive liquid crystal panel 40G of the light modulation device 140G. The second polarizing element 433 is disposed at an angle of 45° with respect to the principal ray of the incident green light LG. With this configuration, it is easy to control the exit direction of the S-polarized component separated by the second polarizing element 433, so that the separated light can be efficiently incident on the light modulation device 140G. In the following description, unless otherwise specified, the notations S-polarized light and P-polarized light for the green light LG refer to the polarization direction with respect to the transmissive liquid crystal panel 40G.

[0108] FIG. 8 is a graph showing the spectral characteristics of the second polarizing element 433. As shown in FIG. 8, the second polarizing element 433 has the spectral characteristics of transmitting P-polarized light of green light LG in a green wavelength band (third wavelength band) of 520 nm to 545 nm and reflecting S-polarized light of the green light LG.

[0109] Here, the green light LG consisting of laser light emitted from the illumination device 420 is emitted as S-polarized light, but since it passes through multiple optical components before entering the second polarizing element 433, slight disturbance occurs in the polarization direction. Therefore, although the green light LG is mainly composed of S-polarized light, it also contains a small amount of P-polarized light.

[0110] The second polarizing element 433 transmits green light LGp, which is a P-polarized component of the incident green light LG, and reflects green light LGs, which is an S-polarized component of the green light LG. Note that the amount of green light LGp transmitted through the second polarizing element 433 is very small, and is blocked by a light blocking member (not shown), so it does not become a cause of stray light.

[0111] In this way, the second polarizing element 433 separates the green light LGs, which is the S-polarized component that is the first polarization component of the green light LG, and causes it to enter the transmissive liquid crystal panel 40G of the optical modulation device 140G. The transmissive liquid crystal panel 40G of this embodiment corresponds to the "second transmissive liquid crystal panel" in the claims.

[0112] The second dichroic mirror 434 separates the green light LGp and the red light LR emitted from the second polarizing element 433. The second dichroic mirror 434 transmits the blue light LBp and reflects the red light LR. Note that the amount of blue light LBp transmitted through the second dichroic mirror 434 is very small, and is blocked by a light blocking member (not shown), so it does not become a cause of stray light.

[0113] The third polarizing element 435 is disposed on the optical path of the red light LR reflected by the second dichroic mirror 434. The third polarizing element 435 reflects a predetermined polarized component of the red light LR and causes it to enter the light modulation device 140R.

[0114] The third polarizing element 435 of this embodiment has the same spectral characteristics as the second polarizing element 335 of the third embodiment shown in Fig. 6. Therefore, the third polarizing element 435 separates the red light LRs, which is the S-polarized component that is the first polarized component of the red light LR, and causes it to enter the transmissive liquid crystal panel 40R of the light modulation device 140R. The transmissive liquid crystal panel 40R of this embodiment corresponds to the "third transmissive liquid crystal panel" in the claims.

[0115] The first relay lens 236 is disposed on the optical path of the red light LR between the second polarizing element 433 and the second dichroic mirror 434. The second relay lens 237 is disposed on the optical path of the red light LR between the second dichroic mirror 434 and the third polarizing element 435. By disposing the first relay lens 236 and the second relay lens 237, optical loss caused by the difference in optical path length of the red light LR is compensated for.

[0116] In the case of the projector 104 of this embodiment, none of the light modulation devices 140R, 140G, and 140B has an incident side polarizing plate, and only has an exit side polarizing plate 41R, 41G, and 41B on the light exit side of the transmissive liquid crystal panels 40R, 40G, and 40B. According to the projector 104 of the present embodiment, the red light LRs, green light LGs, and blue light LBs, which are respectively polarized and separated from the red light LR, green light LG, and blue light LB of the laser light by the polarization element formed of a dielectric multilayer film, can be made to enter the liquid crystal panels 40R, 40G, and 40B. Therefore, the projector 104 of the present embodiment can project a bright color image by efficiently using the illumination light WL2 emitted from the illumination device 420.

[0117] 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 illumination device and the color separation optical system, and the other configurations are common. The illumination device of this embodiment is also common to the illumination device 320 of the third embodiment. The configurations of the illumination device and the color separation optical system will be mainly described below, and the same reference numerals will be used for the members common to the above embodiments, and detailed description will be omitted.

[0118] FIG. 9 is a diagram showing a schematic configuration of a projector 105 according to the present embodiment. 9, the projector 105 of this embodiment includes an illumination device 320, a color separation optical system 530, light modulation devices 140R, 140G, and 140B, a color synthesis optical system 150, and a projection optical system 160. The positional relationship of the light modulation devices 140R, 140G, and 140B with respect to the color synthesis optical system 150 in the projector 105 of this embodiment is equal to the positional relationship in the projector 103 of the third embodiment. Note that some of the components of the color separation optical system 530 are common to some of the components of the color separation optical system 530 of the third embodiment, and therefore the common components are denoted by the same reference numerals and description thereof will be omitted.

[0119] As shown in Fig. 9, the illumination device 320 emits illumination light WL1 toward the color separation optical system 530. The color separation optical system 530 separates the illumination light WL1 into red light LR, green light LG, and blue light LB. The red light LR corresponds to the red light R contained in the illumination light WL1, the green light LG corresponds to the green fluorescence GL contained in the illumination light WL1, and the blue light LB corresponds to the blue light B contained in the illumination light WL1. In other words, the green light LG in this embodiment corresponds to the "second light in the second wavelength band" in the claims, and the red light LR in this embodiment corresponds to the "second laser light in the fourth wavelength band" in the claims.

[0120] The color separation optical system 530 includes a first polarizing element 531 , a first dichroic mirror 532 , a second dichroic mirror 533 , a third dichroic mirror 234 , a mirror 534 , a first relay lens 236 , and a second relay lens 237 .

[0121] The first polarizing element 531 is disposed on the optical path of the illumination light WL1 emitted from the lighting device 320, and separates the incident illumination light WL1 into red light LR, green light LG, and blue light LB. Specifically, the first polarizing element 531 transmits the green light LG of the illumination light WL1. In addition, the first polarizing element 531 transmits blue light LBp, which is a P-polarized component of the blue light LB, and reflects blue light LBs, which is an S-polarized component. In addition, the first polarizing element 531 transmits red light LRp, which is a P-polarized component of the red light LR, and reflects red light LRs, which is an S-polarized component.

[0122] The first polarizing element 531 includes a first surface M1 on which the illumination light WL1 is incident and a second surface M2 opposite to the first surface M1. The first polarizing element 531 has a first film 531a arranged on the first surface M1 side, a second film 531b arranged on the second surface M2 side, and a transparent base material 531c that supports the first film 531a and the second film 531b. In other words, the surface of the first film 531a opposite to the transparent base material 531c corresponds to the first surface M1, and the surface of the second film 531b opposite to the transparent base material 531c corresponds to the second surface M2.

[0123] The first film 531a is made of a dielectric multilayer film and has an optical property of transmitting the red light LR of the illumination light WL1 while reflecting the blue light LBs, which is a first polarization component of the blue light LB. The first film 531a also has an optical property of transmitting the blue light LBp, which is a second polarization component of the blue light LB. The blue light LBs reflected by the first film 531a is emitted toward the first dichroic mirror 532. The red light LR and the blue light LBp are transmitted through the transparent base material 531c and enter the second film 531b.

[0124] The second film 531b is made of a dielectric multilayer film and has the optical property of reflecting the red light LRs, which is the first polarization component of the red light LR, while transmitting the blue light LBp of the blue light LB. The red light LRs reflected by the second film 531b is transmitted through the transparent base material 531c and the first film 531a and emitted toward the first dichroic mirror 532.

[0125] The first dichroic mirror 532 is disposed on the optical path of the blue light LBs and the red light LRs reflected by the first polarizing element 531. The first dichroic mirror 532 separates the blue light LBs and the red light LRs by reflecting the blue light LBs and transmitting the red light LRs. In this manner, the blue light LBs enters the optical modulation device 140B from the first dichroic mirror 532. That is, the first dichroic mirror 532 in this embodiment corresponds to the "light separating element" in the claims.

[0126] The second dichroic mirror 533 separates the blue light LBp, red light LRp, and green light LG transmitted through the first polarizing element 531 into the blue light LBp, red light LRp, and green light LG. The second dichroic mirror 533 transmits the blue light LBp and red light LRp, and reflects the green light LG. That is, the second dichroic mirror 533 reflects the green light LG and transmits the blue light LBp and red light LRp, thereby separating the green light LG from the red light LRp and blue light LBp. In this way, the green light LG is incident on the light modulation device 140G from the first dichroic mirror 233.

[0127] The third dichroic mirror 234 is disposed on the optical path of the blue light LBp and the red light LR emitted from the second dichroic mirror 533, and separates the blue light LBp from the red light LR. The third dichroic mirror 234 transmits the blue light LBp and reflects the red light LR. Note that the amount of blue light LBp transmitted through the third dichroic mirror 234 is very small, and is blocked by a light blocking member (not shown), so it does not become a cause of stray light.

[0128] The mirror 534 is disposed on the optical path of the red light LRs emitted from the third dichroic mirror 234, and reflects the red light LRs toward the light modulation device 140R. In this manner, the red light LRs, which is the S-polarized component that is the first polarization component of the red light LR, is incident on the transmissive liquid crystal panel 40R of the light modulation device 140R. The transmissive liquid crystal panel 40R of this embodiment corresponds to the "second transmissive liquid crystal panel" in the claims.

[0129] The first relay lens 236 is disposed on the optical path of the red light LR between the second dichroic mirror 533 and the third dichroic mirror 234. The second relay lens 237 is disposed on the optical path of the red light LR between the third dichroic mirror 234 and the mirror 534. By disposing the first relay lens 236 and the second relay lens 237, optical loss caused by the difference in optical path length of the red light LR is compensated for.

[0130] According to the projector 105 of this embodiment, the polarization directions of the blue light LB and the red light LR are aligned in the first polarizing element 531, so that a bright image can be projected by reducing the number of polarizing elements used in the color separation optical system 530 while increasing the light utilization efficiency.

[0131] 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. The specific description of the shape, number, arrangement, material, and the like of each component of the projector shown in the above embodiment is not limited to the above embodiment and can be changed as appropriate.

[0132] For example, in the first embodiment of the projector 100, a case has been given in which the blue light LB contained in the illumination light WL is generated by laser light, and the green light LG and red light LR are generated by fluorescence, but the present invention is also applicable to a case in which either one of the green light LG and the red light LR is generated by laser light, and the other two colors of light are generated by fluorescence.

[0133] In addition, in the third embodiment of the projector 103, an example is given in which the green light LG contained in the illumination light WL1 is generated by fluorescence and the red light LR is generated by laser light, but the present invention is also applicable to cases in which the green light LG is generated by laser light and the red light LR is generated by fluorescence.

[0134] The following is a summary of this disclosure. (Appendix 1) a light source that emits light including a first laser beam in a first wavelength band; a first polarizing element formed of a dielectric multilayer film and configured to separate a first polarized component of the first laser light incident thereon; a first transmissive liquid crystal panel that modulates the first polarized component of the first laser light separated by the first polarizing element; a projection optical system that projects light modulated by the first transmissive liquid crystal panel; Equipped with the first polarizing element separates the first polarized component of the first laser light and causes the first polarized component to be incident on the first transmissive liquid crystal panel; projector.

[0135] According to the projector having this configuration, the first polarized component polarized and separated from the first laser light by the first polarizing element made of a dielectric multilayer film is incident on the first transmissive liquid crystal panel, so that the light utilization efficiency of the first laser light can be improved. Therefore, the first transmissive liquid crystal panel can modulate bright image light. Therefore, the projector having this configuration can project a bright image by efficiently utilizing the first laser light emitted from the light source.

[0136] (Appendix 2) Further comprising a polarization conversion element that converts the light emitted from the light source into the first polarization component. 2. The projector according to claim 1.

[0137] According to this configuration, the illumination light emitted from the light source is converted into the first polarized component by the polarization conversion element, so that the loss that occurs when the illumination light is polarized and separated can be reduced, and the light utilization efficiency can be further improved.

[0138] (Appendix 3) the light emitted from the light source further includes a second light consisting of fluorescence in a second wavelength band different from the first wavelength band, the first polarizing element separates the first polarized component of the first laser light from the second light by transmitting the second light incident thereon; 1. The projector according to claim 1 or 2.

[0139] According to this configuration, even when the illumination light emitted from the light source contains the second light made of fluorescent light, it is possible to separate the first polarized component of the first laser light from the illumination light.

[0140] (Appendix 4) the light emitted from the light source further includes a second laser light in a third wavelength band different from the first wavelength band; a light separation element that separates the first laser light from the second laser light by reflecting the first laser light and transmitting the second laser light; a second polarizing element formed of a dielectric multilayer film and configured to separate the first polarized component of the second laser light incident from the light separating element by reflecting the first polarized component; a second transmissive liquid crystal panel that modulates the first polarized component of the second laser light separated by the second polarizing element; 1. The projector according to claim 1 or 2.

[0141] According to this configuration, since the second polarizing element made of a dielectric multilayer film is provided, the first polarized component polarized and separated from the second laser light can be made incident on the second transmissive liquid crystal panel. Therefore, when the illumination light emitted from the light source contains the first laser light and the second laser light in different wavelength bands, it is possible to project a bright color image by efficiently using the illumination light.

[0142] (Appendix 5) the light emitted from the light source further includes a third laser light in a fourth wavelength band different from the first laser light and the second laser light, the second polarizing element separates an optical path of the first polarized component of the second laser light from an optical path of the third laser light by transmitting the third laser light; 5. The projector according to claim 4.

[0143] According to this configuration, even if the illumination light emitted from the light source contains the third laser light, it is possible to separate the first polarized component of the second laser light from the illumination light.

[0144] (Appendix 6) a third polarizing element formed of a dielectric multilayer film and configured to separate the first polarized component of the third laser light incident upon the third polarizing element by reflecting the first polarized component; a third transmissive liquid crystal panel that modulates the first polarized component of the third laser light separated by the third polarizing element; 6. The projector according to claim 5.

[0145] According to this configuration, since the third polarizing element made of a dielectric multilayer film is provided, the first polarized component polarized and separated from the third laser light can be made incident on the third transmissive liquid crystal panel. Therefore, a bright color image can be projected by efficiently using the illumination light including the three different color laser lights.

[0146] (Appendix 7) the first laser light is a blue laser light, the second laser light is a green laser light, The third laser light is a red laser light. 7. The projector according to claim 6.

[0147] According to this configuration, it is possible to realize a projector that projects bright full-color images by efficiently using illumination light that includes RGB laser light.

[0148] (Appendix 8) the light emitted from the light source further includes a second laser light in a fourth wavelength band different from the first wavelength band; a light separation element that separates the second light from the second laser light by reflecting the second light and transmitting the second laser light; a second polarizing element formed of a dielectric multilayer film and configured to separate the first polarized component of the second laser light incident from the light separating element by reflecting the first polarized component; a second transmissive liquid crystal panel that modulates the first polarized component of the second laser light separated by the second polarizing element; 4. The projector according to claim 3.

[0149] According to this configuration, when the illumination light emitted from the light source contains the second light composed of fluorescence and the second laser light, the first polarized component of the second laser light separated from the illumination light can be made to enter the second transmissive liquid crystal panel. Therefore, a bright color image can be projected by efficiently using the illumination light containing the laser lights of two different colors.

[0150] (Appendix 9) the light emitted from the light source further includes a second laser light in a fourth wavelength band different from the first wavelength band; The first polarizing element is a first film that is disposed on a first surface side to which the light emitted from the light source is incident, and that transmits the second laser light while reflecting the first polarization component of the first laser light; a second film that is disposed on a second surface side opposite to the first surface and reflects the first polarized component of the second laser light while transmitting a second polarized component having a polarization direction different from that of the first polarized component of the first laser light and the second polarized component of the second laser light; a light separation element that separates the first polarization component of the first laser light and the first polarization component of the second laser light by reflecting the first polarization component of the first laser light incident from the first polarization element and transmitting the first polarization component of the second laser light incident from the first polarization element; a second transmissive liquid crystal panel that modulates the second polarized component of the second laser light that has passed through the second film of the first polarizing element, 1. The projector according to claim 1 or 2.

[0151] With this configuration, the polarization directions of the first laser light and the second laser light are aligned in the first polarizing element, thereby realizing a projector that projects bright images by reducing the number of polarizing elements used in the color separation optical system while increasing light utilization efficiency.

[0152] (Appendix 10) The first polarizing element separates the first polarized component from the first laser light by reflecting it. 10. The projector according to claim 1 ,

[0153] According to this configuration, since the first polarized component is separated by reflection from the first laser light, the separated first polarized component can be easily guided to the first transmissive liquid crystal panel side, which makes it easier to layout each member.

[0154] (Appendix 11) The first polarizing element is disposed at an angle of 45 degrees with respect to a principal ray of the first laser light incident thereon. 11. The projector according to claim 10.

[0155] According to this configuration, it is easy to control the emission direction of the first polarized component separated by the first polarizing element, so that the separated light can be made to efficiently enter the first transmissive liquid crystal panel. [Explanation of symbols]

[0156] 2,3,4...light source, 32...polarization conversion element, 40B,40G,40R...transmissive LCD panel, 40R...LCD panel, 100,102,103,104,105...projector, 135,432,531...first polarizing element, 160...projection optical system, 335,433...second polarizing element, 435...third polarizing element, 531a...first film, 531b...second film, Bb...blue laser light, Ep,Es...light ray, Gg...green laser light, GL,YL...fluorescence, M1...first surface, M2...second surface, orG...R fluorescence, Rr...red laser light.

Claims

1. a light source that emits light including a first laser beam in a first wavelength band; a first polarizing element formed of a dielectric multilayer film and configured to separate a first polarized component of the first laser light incident thereon; a first transmissive liquid crystal panel that modulates the first polarized component of the first laser light separated by the first polarizing element; a projection optical system that projects light modulated by the first transmissive liquid crystal panel; Equipped with the first polarizing element separates the first polarized component of the first laser light and causes the first polarized component to be incident on the first transmissive liquid crystal panel; projector.

2. Further comprising a polarization conversion element that converts the light emitted from the light source into the first polarization component. The projector according to claim 1 .

3. the light emitted from the light source further includes second light consisting of fluorescence in a second wavelength band different from the first wavelength band, the first polarizing element separates the first polarized component of the first laser light from the second light by transmitting the second light incident thereon; The projector according to claim 1 .

4. the light emitted from the light source further includes a second laser light in a third wavelength band different from the first wavelength band, a light separation element that separates the first laser light from the second laser light by reflecting the first laser light and transmitting the second laser light; a second polarizing element formed of a dielectric multilayer film and configured to separate the first polarized component of the second laser light incident from the light separating element by reflecting the first polarized component; a second transmissive liquid crystal panel that modulates the first polarized component of the second laser light separated by the second polarizing element, The projector according to claim 1 .

5. the light emitted from the light source further includes a third laser light in a fourth wavelength band different from the first laser light and the second laser light, the second polarizing element separates an optical path of the first polarized component of the second laser light from an optical path of the third laser light by transmitting the third laser light; The projector according to claim 4.

6. a third polarizing element formed of a dielectric multilayer film and configured to separate the first polarized component of the third laser light incident upon the third polarizing element by reflecting the first polarized component; a third transmissive liquid crystal panel that modulates the first polarized component of the third laser light separated by the third polarizing element, The projector according to claim 5 .

7. the first laser light is a blue laser light, the second laser light is a green laser light, The third laser light is a red laser light. The projector according to claim 6.

8. the light emitted from the light source further includes a second laser light in a fourth wavelength band different from the first wavelength band, a light separation element that separates the second light from the second laser light by reflecting the second light and transmitting the second laser light; a second polarizing element formed of a dielectric multilayer film and configured to separate the first polarized component of the second laser light incident from the light separating element by reflecting the first polarized component; a second transmissive liquid crystal panel that modulates the first polarized component of the second laser light separated by the second polarizing element, The projector according to claim 3 .

9. the light emitted from the light source further includes a second laser light in a fourth wavelength band different from the first wavelength band, The first polarizing element is a first film disposed on a first surface side to which the light emitted from the light source is incident, the first film transmitting the second laser light while reflecting the first polarized component of the first laser light; a second film that is disposed on a second surface side opposite to the first surface and reflects the first polarized component of the second laser light while transmitting a second polarized component having a polarization direction different from that of the first polarized component of the first laser light and the second polarized component of the second laser light, a light separation element that separates the first polarization component of the first laser light and the first polarization component of the second laser light by reflecting the first polarization component of the first laser light incident from the first polarization element and transmitting the first polarization component of the second laser light incident from the first polarization element; a second transmissive liquid crystal panel that modulates the second polarized component of the second laser light that has passed through the second film of the first polarizing element, The projector according to claim 1 .

10. The first polarizing element separates the first polarization component from the first laser light by reflecting the first polarization component. The projector according to claim 1 .

11. The first polarizing element is disposed at an angle of 45 degrees with respect to a principal ray of the first laser light incident thereon. The projector according to claim 10.

Images