Projector

Abstract

To reduce the number of components and suppress an increase in size of a three-plate type projector.SOLUTION: In a projector of the present invention, first light in a first wavelength range emitted from a first light source sequentially passes through a first light guide element and a first collimation element, and is incident on a light composition element. Second light in a second wavelength range emitted from a second light source sequentially passes through a second light guide element and a second collimation element, and is incident on the light composition element. Third light in a third wavelength range emitted from a third light source sequentially passes through a third light guide element and a third collimation element, and is incident on the light composition element. A first focal length of the first collimation element is longer than a first length from a first incident end to a first emission end of the first light guide element. A second focal length of the second collimation element is longer than a second length from a second incident end to a second emission end of the second light guide element. A third focal length of the third collimation element is longer than a third length from a third incident end to a third emission end of the third light guide element.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Conventionally, a projector having three liquid crystal panels as a light modulation device for generating image light of each of the three primary colors, that is, a three-panel projector, is known. For example, Patent Document 1 discloses a projector including a light source device having a light source unit and a separation / synthesis element, an illumination optical system, a color separation / synthesis optical system, and a projection optical system. The light source unit emits excitation light for a phosphor. The separation / synthesis element causes a part of the light emitted from the light source unit to be incident on the phosphor, and causes another part of the light emitted from the light source unit to be incident on a diffuser and reflected by the diffuser. The illumination optical system illuminates the light emitted from the light source unit. The color separation / synthesis optical system performs color separation and color synthesis on the light emitted from the illumination optical system. The projection optical system enlarges and projects the color-synthesized image light onto an image display surface such as a screen. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-079820 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the three-plate projector disclosed in Patent Document 1, after white light is generated by the light source device, the white light is separated into color lights by a color separation / synthesis optical system arranged downstream of the light source device. Therefore, the projector disclosed in Patent Document 1 needs to further include a color separation / synthesis optical system in addition to the light source device. As a result, the number of parts increases, which may lead to an increase in the size of the projector. In other words, measures to reduce the number of parts and prevent the projector from becoming larger are desired in three-plate projectors. [Means for solving the problem]

[0005] A projector according to one aspect of the present invention includes a first light source that emits first light in a first wavelength band, a second light source that emits second light in a second wavelength band different from the first wavelength band, a third light source that emits third light in a third wavelength band different from the first wavelength band and the second wavelength band, a first light-guiding element having a first entrance end into which the first light emitted from the first light source is incident and a first exit end from which the first light is emitted, and uniforming an in-plane illuminance of the first light, a second light-guiding element having a second entrance end into which the second light emitted from the second light source is incident and a second exit end from which the second light is emitted, and uniforming an in-plane illuminance of the second light, a third light-guiding element having a third entrance end into which the third light emitted from the third light source is incident and a third exit end from which the third light is emitted, and uniforming an in-plane illuminance of the third light, and the first light-guiding element the first light-guiding element for collimating the first light emitted from the first light-guiding element, the second light-guiding element for collimating the second light emitted from the second light-guiding element, the third light-guiding element for collimating the third light emitted from the third light-guiding element, a first light-modulating element for modulating the first light emitted from the first collimating element based on image information, a second light-modulating element for modulating the second light emitted from the second collimating element based on image information, a third light-modulating element for modulating the third light emitted from the third collimating element based on image information, a light-combining element for combining and outputting the first light emitted from the first light-modulating element, the second light emitted from the second light-modulating element, and the third light emitted from the third light-modulating element, and a projection optical system for projecting the light emitted from the light-combining element. A first focal length of the first collimating element is longer than a first length from the first incident end to the first exit end, a second focal length of the second collimating element is longer than a second length from the second incident end to the second exit end, and a third focal length of the second collimating element is longer than a third length from the third incident end to the third exit end. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of a projector according to an embodiment. [Diagram 2] 2 is a schematic diagram of a green light emission section of the projector in FIG. 1. [Diagram 3]2 is a schematic diagram of a green light output section and an entrance-side polarizing element of the projector in FIG. 1. [Figure 4] 2 is a schematic diagram of a green light emitting section, an incident-side polarizing element, and a light modulation element of the projector in FIG. [Diagram 5] 1. FIG. 4 is a schematic diagram of a modified example of the green light output section of the projector in FIG. [Figure 6] 1. FIG. 4 is a schematic diagram of a modified example of the green light output section of the projector in FIG. [Figure 7] 1. FIG. 4 is a schematic diagram of a modified example of the green light output section of the projector in FIG. [Figure 8] 1. FIG. 4 is a schematic diagram of a modified example of the green light output section of the projector in FIG. [Figure 9] 2 is a schematic diagram of a main part of a green light emitting section of the projector in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the scale of the dimensions of some components may be changed in order to make each component easier to see.

[0008] First, an embodiment of the present invention will be described with reference to Figs. 1 to 5. Fig. 1 is a schematic diagram showing the configuration of a projector 301 according to an embodiment of the present invention. The projector 301 is an image display device having three liquid crystal panels as light modulation devices, and is a so-called three-panel projector. As shown in Fig. 1, the projector 301 includes a blue light emission section 101, a green light emission section 102, a red light emission section 103, incident side polarizing elements 171, 172, and 173, light modulation elements 181, 182, and 183, exit side polarizing elements 175, 176, and 177, a light combining element 200, and a projection optical system 250.

[0009] The blue light output unit 101 outputs blue light LB. In the following description, the direction of an axis parallel to the optical axis of the blue light LB output from the blue light output unit 101 is referred to as the D1 direction. One side in the D1 direction is referred to as the -D1 side, and the opposite side of the -D1 side in the D1 direction is referred to as the +D1 side. A direction perpendicular to the D1 direction in a plane including the optical axis of the blue light LB is referred to as the D2 direction. One side in the D2 direction is referred to as the -D2 side, and the opposite side of the -D2 side in the D2 direction is referred to as the +D2 side. A direction perpendicular to the D1 direction and the D2 direction is referred to as the D3 direction. The blue light LB output from the blue light output unit 101 travels to the +D1 side along the D1 direction.

[0010] The blue light emitting unit 101 has a light source 121, a light guide element 141, and a collimating element 161. The light source 121 is supported by the substrate 111. The light source 121 is provided on a plate surface on the +D1 side of the plate surface of the substrate 111 that is parallel to a plane including the D2 and D3 directions. The light emitting surface of the light source 121 is disposed approximately parallel to the plane including the D2 and D3 directions, and is a surface on the opposite side in the D1 direction to a surface of the light source 121 that is in contact with the plate surface on the +D1 side of the substrate 111. The light source 121 corresponds to a first light source, and emits blue light LB in a blue wavelength band in the visible wavelength band. The blue wavelength band corresponds to a first wavelength band. The blue light LB corresponds to a first light. The blue light LB diverges from the light emitting surface of the light source 121 according to a predetermined radiation angle around an axis that passes through the center of the light emitting surface of the light source 121 and is emitted to the +D1 side. The blue wavelength band is, for example, a wavelength band from 420 nm to 500 nm.

[0011] The light source 121 is composed of, for example, a light emitting diode (LED) that emits blue light LB. The light source 121 may be composed of one LED or a plurality of LEDs as a whole. When the light source 121 is composed of a plurality of LEDs, the plurality of LEDs are arranged in an area occupied by the light source 121 in a plane including the D2 direction and the D3 direction.

[0012] The substrate 111 is made of, for example, a metal, and also functions as a heat dissipation member that receives heat from the light source 121 that emits the blue light LB and dissipates the heat to the external space.

[0013] The light guide element 141 is provided on the optical path of the blue light LB emitted from the light source 121, and is disposed on the +D1 side of the light source 121 and at a position overlapping with the light source 121 in the D2 and D3 directions. The light guide element 141 corresponds to a first light guide element, and has an incident end 141a on the -D1 side in the D1 direction, an exit end 141b on the +D1 side, and a side surface 141s and a reflecting surface 141r extending between the incident end 141a and the exit end 141b in the D1 direction. The incident end 141a corresponds to a first incident end, and extends parallel to a plane including the D2 and D3 directions. The shape of the incident end 141a when viewed from the D1 direction is the same as the shape of the light emitting surface of the light source 121 when viewed from the same direction, and is, for example, rectangular. The size of the incident end 141a in the plane including the D2 and D3 directions may be equivalent to the size of the light emitting surface of the light source 121 in the plane including the D2 and D3 directions, but is preferably appropriately larger than the size of the light emitting surface of the light source 121 in the plane including the D2 and D3 directions. The exit end 141b corresponds to the first exit end, extends parallel to the plane including the D2 and D3 directions, and is larger than the incident end 141a. The shape of the exit end 141b when viewed from the D1 direction is similar to the modulation surface of the light modulation element 181 when viewed from the same direction, and is, for example, rectangular. The size of the exit end 141b in the plane including the D2 and D3 directions is equivalent to the size of the modulation surface of the light modulation element 181 in the plane including the D2 and D3 directions. The side surface 141s and the reflecting surface 141r connect the peripheral portion of the incident end 141a and the peripheral portion of the exit end 141b in the D1 direction.

[0014] The blue light LB emitted from the light source 121 enters the light guide element 141 from the incident end 141a. In the light guide element 141, the area surrounded by the incident end 141a, the exit end 141b, and the reflecting surface 141r is the area through which the blue light LB propagates. The size of the area surrounded by the incident end 141a, the exit end 141b, and the reflecting surface 141r in the plane including the D2 and D3 directions increases as it progresses from the -D1 side to the +D1 side in the D1 direction. In addition, the shape of the area surrounded by the incident end 141a, the exit end 141b, and the reflecting surface 141r in the plane including the D2 and D3 directions changes from the shape of the light emitting surface of the light source 121 when viewed from the D1 direction to the shape of the modulation surface of the light modulation element 181 as it progresses from the -D1 side to the +D1 side.

[0015] A side surface 141s of the light guide element 141 and a reflecting surface 141r provided on the side surface 141s as described below form a predetermined angle with respect to a virtual line perpendicular to the incident end 141a and the optical axis, and move away from the virtual line in a plane including the D2 and D3 directions as they move from the -D1 side to the +D1 side. The blue light LB incident on the light guide element 141 propagates from the -D1 side to the +D1 side within a region surrounded by the incident end 141a, the exit end 141b, and the reflecting surface 141r.

[0016] When the shape of the modulation surface of the light modulation element 181 is rectangular when viewed in the D1 direction, the shape of the light emitting surface of the light source 121 when viewed in the D1 direction is also rectangular. In this case, the predetermined angle α, i.e., the taper angle, that the side surface 141s and the reflecting surface 141r including the short side of the rectangular shape make with respect to the virtual line and the optical axis is preferably within a range of 7° to 22°. The predetermined angle β, i.e., the taper angle, that the side surface 141s and the reflecting surface 141r including the long side of the rectangular shape make with respect to the virtual line and the optical axis is preferably within a range of 14° to 36°. The preferred ranges of the angles α and β have been confirmed by a numerical simulation based on the configuration of the blue light emitting unit 101 and ray tracing.

[0017] A part of the blue light LB incident on the light guide element 141 forms an angle smaller than a predetermined angle with respect to the virtual axis and the optical axis described above, does not enter the reflecting surface 141r even once, and propagates directly from the incident end 141a to the exit end 141b. A remaining part of the blue light LB incident on the light guide element 141 forms an angle equal to or larger than a predetermined angle with respect to the virtual axis and the optical axis described above, enters the reflecting surface 141r from the incident end 141a one or more times, is reflected by the reflecting surface 141r, and then reaches the exit end 141b. The path of the blue light LB in the area surrounded by the incident end 141a, the exit end 141b, and the reflecting surface 141r varies depending on the angle of incidence on the incident end 141a, and extends along a plurality of paths that are reflected by the reflecting surface 141r a different number of times. As a result, the illuminance distribution of the blue light LB propagating through the region surrounded by the incident end 141a, the exit end 141b, and the reflecting surface 141r is uniformized within a plane including the D2 and D3 directions. That is, the light guide element 141 uniformizes the illuminance distribution of the incident blue light LB within a plane including the D2 and D3 directions. The blue light LB with the uniform illuminance distribution is emitted from the exit end 141b to the +D1 side.

[0018] The light guide element 141 is a reflector made of a transparent material such as optical glass. The reflector has a frame and is formed as a hollow member. When viewed along the D1 direction, the -D1 side end of the frame of the reflector has the same shape and size as the entrance end 141a and the light emitting surface of the light source 121, and is formed, for example, in a rectangular frame shape. The +D1 side end of the frame of the reflector has the same shape and size as the exit end 141b and the modulation surface of the light modulation element 181, and is formed, for example, in a rectangular frame shape of a different size from the end on the -D1 side.

[0019] The reflector is composed of, for example, a plate-like member made of a transparent material. As described above, if the shape of the incident end 141a and the exit end 141b when viewed from the D1 direction is rectangular, the reflector is composed of four plate-like members having a trapezoidal shape. The length of the side parallel to the D2 direction or the D3 direction on the -D1 side corresponding to the upper base of the four plate-like members is set according to the incident end 141a and the size of the light-emitting surface of the light source 121 in the D2 direction or the D3 direction. The length of the side parallel to the D2 direction or the D3 direction on the +D1 side corresponding to the lower base of the four plate-like members is set according to the exit end 141b and the size of the modulation surface of the light modulation element 181 in the D2 direction or the D3 direction. Of the four plate-like members, the side corresponding to the leg on one side of one of the two plate-like members is connected to the side corresponding to the leg on the other side of the other plate-like member.

[0020] As described above, when the reflector is formed of a plate-like member made of a transparent member, the side surface 141s, i.e., the plate surface of the plate-like member facing the external space of the reflector, acts as the reflection surface 141r. In the reflector of the light guide element 141, in order to increase the reflectance of the blue light LB incident on the light guide element 141 from the incident end 141a near the side surface 141s, a reflection film 251 made of a dielectric multilayer film or the like is provided on the plate surface facing the internal space of the plate-like member constituting the reflector. A part of the blue light LB incident on the internal space of the reflector of the light guide element 141 from the incident end 141a is reflected by the reflection film 251 and proceeds to the +D1 side.

[0021] The intensity of the blue light LB reflected by the reflective film 251 and emitted from the reflective film 251 may depend on the angle of incidence of the blue light LB incident on the reflective film 251. When the reflective film 251 is made of a dielectric multilayer film, the incidence angle dependency of the intensity of the blue light LB emitted from the reflective film 251 changes depending on parameters such as the refractive index, thickness, and number of films of the multiple films included in the dielectric multilayer film. As described above, the reflective film 251 is designed and the parameters of the dielectric multilayer film are appropriately determined so that, for example, when the angle α is within the range of 7° to 22° and the angle β is within the range of 14° to 36°, the incidence angle of the blue light LB at which the intensity of the blue light LB emitted from the reflective surface 141r is the highest is within the range of 60° to 90°. The relationship between the angle of incidence of the blue light LB on the reflective surface 141r and the reflective film 251 and the intensity of the blue light LB emitted from the reflective surface 141r and the reflective film 251 is obtained by a numerical simulation based on the configuration of the blue light emitting unit 101 and ray tracing.

[0022] In addition, when the reflector is composed of a plate-like member made of a transparent material, and the plate surface of the plate-like member facing the external space of the reflector acts as the reflecting surface 141r, a portion of the blue light LB incident on the incident end 141a into the internal space of the reflector of the light-guiding element 141 enters the plate-like member from the plate surface facing the internal space of the reflector, refracts, is reflected by the plate surface facing the external space of the reflector, propagates through the plate-like member again, refracts by the plate surface facing the internal space of the reflector, is emitted into the internal space of the reflector, and proceeds toward the +D1 side.

[0023] The collimating element 161 is provided on the optical path of the blue light LB emitted from the light guide element 141, and is disposed on the +D1 side of the light guide element 141 at a position overlapping with the light guide element 141 in the D2 and D3 directions. The collimating element 161 corresponds to a first collimating element, and collimates the blue light LB emitted from the light guide element 141 along the D1 direction.

[0024] The collimating element 161 is, for example, a plano-convex lens, and has an entrance surface made of a flat surface perpendicular to the D1 direction, and an exit surface made of a convex curved surface protruding toward the exit side of the blue light LB. The focal point of the plano-convex lens constituting the collimating element 161 is at least on the -D1 side of the collimating element 161, and is opposite to the +D1 side from which the blue light LB is exited from the collimating element 161, and is further on the -D1 side of the light guide element 141. The entrance surface of the plano-convex lens of the collimating element 161 is in contact with the exit end 141b of the light guide element 141. By the collimating element 161 being in contact with the exit end 141b, the blue light LB exited from the exit end 141b of the light guide element 141 is taken in by the collimating element 161 to the maximum extent, and loss of the blue light LB is suppressed. However, the parallelizing element 161 may be an optical lens other than a plano-convex lens that can parallelize the incident blue light LB, and may be disposed at an appropriate distance from the light guide element 141 in the D1 direction.

[0025] The focal length f1 of the collimating element 161 corresponds to a first focal length and is longer than the length g1 from the incident end 141a to the exit end 141b of the light guide element 141 in the D1 direction. The length g1 corresponds to a first length. Specifically, the focal length f1 of the collimating element 161 is preferably 1.1 times or more the length g1 of the light guide element 141. It is more preferable that the focal length f1 is 1.1 times or more and 2.0 times or less the length g1. By setting the focal length f1 within the above-mentioned range, the blue light LB emitted from the light source 121 is efficiently collimated, and the utilization efficiency of the blue light LB is improved. The preferable range of the focal length f1 has been confirmed by a numerical simulation based on the configuration of the blue light emitting unit 101 and ray tracing.

[0026] When the focal length f1 of the collimating element 161 is shorter than 1.1 times the length g1 of the light guide element 141, the illumination range of the blue light LB emitted from the collimating element 161 is excessively reduced, and when the image light converted by the downstream light modulation element 181 is projected and enlarged and displayed on the screen SC, there is a possibility that a part of the original image will not be displayed. On the other hand, when the focal length f1 is longer than 2.0 times the length g1, a part of the blue light LB emitted from the collimating element 161 will not enter the light modulation element 181 arranged downstream of the collimating element 161. As a result, there is a possibility that the utilization efficiency of the blue light LB will decrease.

[0027] The incident side polarizing element 171 is provided on the optical path of the blue light LB emitted from the parallelizing element 161, and is disposed on the +D1 side of the parallelizing element 161 and at a position overlapping with the parallelizing element 161 in the D2 direction and the D3 direction. The incident side polarizing element 171 is in contact with the light modulation element 181 from the -D1 side, for example, but may be disposed at an appropriate interval from the light modulation element 181 in the D1 direction. The incident side polarizing element 171 corresponds to a first polarizing element, and emits a predetermined polarized light of the blue light LB emitted from the parallelizing element 161 to the +D1 side along the D1 direction. The predetermined polarized light corresponds to a first polarized component, and is, for example, S-polarized light. The incident side polarizing element 171 is, for example, a reflective polarizing plate having a plate surface parallel to a plane including the D2 direction and the D3 direction. The incident-side polarizing element 171 transmits a portion of the incident blue light LB that contains a predetermined polarization to the +D1 side, and reflects the other portion of the blue light LB to the -D1 side.

[0028] The light modulation element 181 is provided on the optical path of the blue light LB emitted from the incident-side polarizing element 171, and is disposed on the +D1 side of the incident-side polarizing element 171 at a position overlapping with the incident-side polarizing element 171 in the D2 and D3 directions. The light modulation element 181 corresponds to a first light modulation element, and modulates the blue light LB emitted from the incident-side polarizing element 171 based on image information transmitted from an image forming device such as a computer (not shown) connected to the light modulation element 181 from the outside.

[0029] The light modulation element 181 is, for example, a transmissive liquid crystal panel. The liquid crystal panel constituting the light modulation element 181 has a plurality of pixels (not shown). Each pixel includes a switching element. The switching element is, for example, a polysilicon thin film transistor (TFT). An electrical signal corresponding to the brightness of red light at the relative position of each pixel on the modulation surface of the light modulation element 181 in the image projected by the projector 301 is supplied to the switching element of each pixel. Each pixel modulates the vibration direction of the blue light LB incident from the incident side polarizing element 171 by the operation of the switching element corresponding to the electrical signal, and generates blue image light IB. The image light IB corresponds to the first light. The light modulation element 181 emits the image light IB generated by the liquid crystal panel to the +D1 side along the D1 direction.

[0030] The exit side polarizing element 175 is provided on the optical path of the image light IB exiting from the light modulation element 181, and is disposed on the +D1 side of the light modulation element 181 and at a position overlapping with the light modulation element 181 in the D2 direction and the D3 direction. The exit side polarizing element 175 is in contact with the light modulation element 181 from the +D1 side, for example, but may be disposed at an appropriate interval from the light modulation element 181 in the D1 direction. The exit side polarizing element 175 corresponds to a fourth polarizing element, and emits a predetermined polarized light of the image light IB exiting from the light modulation element 181 to the +D1 side along the D1 direction. The predetermined polarized light corresponds to the fourth polarized component, and is, for example, P polarized light. The exit side polarizing element 175 is, for example, a reflective polarizing plate or an absorptive polarizing plate having a plate surface parallel to a plane including the D2 direction and the D3 direction. In addition, when it is desired to suppress return light and stray light to the light modulation element 181, it is desirable to employ an absorptive polarizing plate as the exit-side polarizing element 175. The exit-side polarizing element 175 transmits a portion of the incident image light IB, which includes a predetermined polarization, to the +D1 side, and reflects the other portion of the image light IB to the -D1 side.

[0031] The green light emitting portion 102 is disposed on the +D1 side and the -D2 side of the blue light emitting portion 101, and is disposed in a region overlapping with the blue light emitting portion 101 in the D3 direction. The green light emitting portion 102 emits green light LG. The green light LG emitted from the green light emitting portion 102 travels toward the +D2 side along the D2 direction.

[0032] The green light emitting unit 102 has a light source 122, a light guide element 142, and a parallelizing element 162. FIG. 2 is a schematic diagram of the green light emitting unit 102, and is a diagram of the green light emitting unit 102 when viewed along the D3 direction. FIG. 3 is a schematic diagram of the green light emitting unit 102 and the incident side polarizing element 172, and is a diagram of the green light emitting unit 102 and the incident side polarizing element 172 when viewed along the D3 direction. As shown in FIGS. 1 to 3, the light source 122 is supported by the substrate 112. The light source 122 is provided on the plate surface on the +D2 side of the plate surface of the substrate 112 that is parallel to the plane including the D1 direction and the D3 direction. The light emitting surface 122a of the light source 122 is disposed approximately parallel to the plane including the D1 direction and the D3 direction, and is a surface on the opposite side in the D2 direction from the surface of the light source 122 that contacts the plate surface on the +D2 side of the substrate 112. The light source 122 corresponds to a second light source, and emits green light LG in a green wavelength band in the visible wavelength band. The green wavelength band is, for example, a wavelength band of 500 nm to 600 nm.

[0033] The light source 122 is, for example, composed of an LED that emits green light LG. In the green light emitting unit 102, in order to optimize the blue wavelength band and intensity of the blue light LB emitted by the blue light emitting unit 101 and the green wavelength band and intensity of the green light LG relative to the red wavelength band and intensity of the red light LR emitted by the red light emitting unit 103, the light source 122 is composed of an LED that incorporates a phosphor, and has an LED body 125 made of a semiconductor and a phosphor 124. The LED body 125 is provided on the plate surface on the +D2 side of the substrate 112. The LED body 125 may be, for example, an LED that emits blue light LB like the light source 121. The phosphor 124 is laminated on the emission surface 125a on the +D2 side of the LED body 125. The phosphor 124 is excited by the light emitted from the LED body 125 as excitation light, and emits green light LG as fluorescence from the emission surface 124a. The type and material of the LED body 125 and the type and material of the phosphor 124 are appropriately selected so that the phosphor 124 excited by the light emitted from the LED body 125 emits green light LG in the green wavelength band.

[0034] Similarly to the light source 121, the light source 122 may be composed of one LED or may be composed of a plurality of LEDs. When the light source 122 is composed of a plurality of LEDs, the plurality of LEDs are arranged in an area occupied by the light source 122 in a plane including the D1 direction and the D3 direction.

[0035] The substrate 112 is made of, for example, a metal, and also functions as a heat dissipation member that receives heat from the light source 122 emitting the green light LG and dissipates the heat to the external space.

[0036] The light guide element 142 is provided on the optical path of the green light LG emitted from the light source 122, and is disposed on the +D2 side of the light source 122 and at a position overlapping with the light source 122 in the D1 direction and the D3 direction. The light guide element 142 corresponds to a second light guide element, and has an incident end 142a on the -D2 side in the D2 direction, an exit end 142b on the +D2 side, and a side surface 142s and a reflecting surface 142r extending between the incident end 142a and the exit end 142b in the D2 direction. The incident end 142a corresponds to a second incident end, and extends parallel to a plane including the D1 direction and the D3 direction. The shape of the incident end 142a when viewed from the D2 direction is the same as the shape of the light emitting surface 122a of the light source 122 when viewed from the same direction, and is, for example, rectangular. The size of the incident end 142a in the plane including the D1 and D3 directions may be equivalent to the size of the light emitting surface 122a of the light source 122 in the plane including the D1 and D3 directions, but is preferably moderately larger than the size of the light emitting surface 122a in the plane including the D1 and D3 directions. The exit end 142b corresponds to a second exit end, extends parallel to the plane including the D1 and D3 directions, and is larger than the incident end 142a. The shape of the exit end 142b when viewed from the D2 direction is similar to the modulation surface of the light modulation element 182 when viewed from the same direction, and is, for example, rectangular. The size of the exit end 142b in the plane including the D1 and D3 directions is equivalent to the size of the modulation surface of the light modulation element 182 in the plane including the D1 and D3 directions. The side surface 142s and the reflecting surface 142r connect the peripheral portion of the entrance end 142a and the peripheral portion of the exit end 142b in the direction D2.

[0037] The green light LG emitted from the light source 122 enters the light guide element 142 from the incident end 142a. In the light guide element 142, the area surrounded by the incident end 142a, the exit end 142b, and the reflecting surface 142r is the area through which the green light LG propagates. The size of the area surrounded by the incident end 142a, the exit end 142b, and the reflecting surface 142r in the plane including the D1 and D3 directions increases as it progresses from the -D2 side to the +D2 side in the D2 direction. In addition, the shape of the area surrounded by the incident end 142a, the exit end 142b, and the reflecting surface 142r in the plane including the D1 and D3 directions changes from the shape of the light emitting surface 122a of the light source 122 when viewed from the D2 direction to the shape of the modulation surface of the light modulation element 182 as it progresses from the -D2 side to the +D2 side.

[0038] A side surface 142s of the light guide element 142 and a reflecting surface 142r provided on the side surface 142s as described below form a predetermined angle with respect to a virtual line VX perpendicular to the incident end 142a and the optical axis, and move away from the virtual line in a plane including the D2 and D3 directions as one moves from the -D2 side to the +D2 side. The green light LG incident on the light guide element 142 propagates from the -D2 side to the +D2 side within a region surrounded by the incident end 142a, the exit end 142b, and the reflecting surface 142r.

[0039] When the shape of the modulation surface of the light modulation element 182 is rectangular when viewed in the D2 direction, the shape of the light emitting surface 122a of the light source 122 when viewed in the D2 direction is also rectangular. In this case, the predetermined angle α that the side surface 142s including the short side of the rectangle and the reflecting surface 142r make with the virtual line and the optical axis is preferably within a range of 7° to 22°. The predetermined angle β that the side surface 141s including the long side of the rectangle and the reflecting surface 141r make with the virtual line and the optical axis is preferably within a range of 14° to 36°.

[0040] A light ray Lg1, which is a part of the green light LG incident on the light guide element 142, forms an angle smaller than the angle α or the angle β with respect to the virtual axis VX and the optical axis, and does not enter the reflecting surface 142r even once, and propagates directly from the incident end 142a to the exit end 142b. A light ray Lg2, which is a part of the green light LG incident on the light guide element 142, forms an angle equal to or larger than the angle α or the angle β with respect to the virtual axis VX and the optical axis, and enters the reflecting surface 142r once from the incident end 142a, and reaches the exit end 142b after being reflected by the reflecting surface 142r. The light rays other than the light ray Lg2, which is a part of the green light LG incident on the light guide element 142, enter the reflecting surface 142r from the incident end 142a two or more times, and reach the exit end 142b after being repeatedly reflected by the reflecting surface 142r. The path of the green light LG in the area surrounded by the incident end 142a, the exit end 142b, and the reflecting surface 142r varies depending on the angle of incidence to the incident end 142a, and extends over a number of paths with different numbers of reflections at the reflecting surface 142r. As a result, the illuminance distribution of the green light LG propagated through the area surrounded by the incident end 142a, the exit end 142b, and the reflecting surface 142r is uniformized within a plane including the D1 and D3 directions. That is, the light guide element 142 uniformizes the illuminance distribution of the incident green light LG within a plane including the D1 and D3 directions. The green light LG with the uniform illuminance distribution is emitted from the exit end 142b to the +D2 side.

[0041] The light guide element 142 is a hollow reflector made of a plate-like member made of a transparent material such as optical glass, similar to the light guide element 141. When viewed along the D2 direction, the end of the -D2 side of the frame of the reflector has the same shape and size as the entrance end 142a and the light emitting surface 122a of the light source 122, and is formed, for example, in a rectangular frame shape. The end of the +D2 side of the frame of the reflector has the same shape and size as the exit end 142b and the modulation surface of the light modulation element 182, and is formed, for example, in a rectangular frame shape of a different size from the end of the -D2 side.

[0042] The reflector of the light guide element 142 is formed by connecting the sides corresponding to the legs of four plate-like members having a trapezoid shape. The length of the side parallel to the D1 direction or the D3 direction on the -D2 side corresponding to the upper base of the four plate-like members is set according to the size of the entrance end 142a and the light-emitting surface 122a in the D1 direction or the D3 direction. The length of the side parallel to the D1 direction or the D3 direction on the +D2 side corresponding to the lower base of the four plate-like members is set according to the size of the exit end 142b and the modulation surface of the light modulation element 182 in the D1 direction or the D3 direction.

[0043] In the reflector of the light-guiding element 142, in order to increase the reflectance of the green light LG incident from the incident end 142a in the vicinity of the side surface 142s, a reflective film 252 such as a dielectric multilayer film is provided on the plate surface opposite to the side surface 142s in the plate member constituting the reflector, i.e., the plate surface facing the internal space of the plate member. Some of the light rays of the green light LG including the light ray Lg2 incident from the incident end 142a into the internal space of the reflector of the light-guiding element 142 are reflected by the reflective film 252 and proceed toward the +D1 side.

[0044] The intensity of the green light LG reflected by the reflective film 252 and emitted from the reflective film 252 may depend on the angle of incidence of the green light LG incident on the reflective film 252. When the reflective film 252 is made of a dielectric multilayer film, the incidence angle dependency of the intensity of the green light LG emitted from the reflective film 252 changes depending on parameters such as the refractive index, thickness, and number of films of the multiple films included in the dielectric multilayer film. As described above, the reflective film 252 is designed and the parameters of the dielectric multilayer film are appropriately determined so that, for example, when the angle α is within the range of 7° to 22° and the angle β is within the range of 14° to 36°, the incidence angle of the green light LG at which the intensity of the green light LG emitted from the reflective surface 142r and the reflective film 252 is the highest is within the range of 60° to 90°. The relationship between the angle of incidence of the green light LG to the reflective film 252 and the intensity of the green light LG emitted from the reflective film 252 is also obtained by a numerical simulation based on the configuration of the green light emitting unit 102 and ray tracing.

[0045] The parallelizing element 162 is provided on the optical path of the green light LG emitted from the light guide element 142, and is disposed on the +D2 side of the light guide element 142 and at a position overlapping with the light guide element 142 in the D1 and D3 directions. The parallelizing element 162 corresponds to a second parallelizing element, and parallelizes the green light LG emitted from the light guide element 142 along the D2 direction.

[0046] The collimating element 162 is, for example, a plano-convex lens, and has an incident surface 162a made of a flat surface perpendicular to the D2 direction, and an exit surface 162b made of a convex curved surface protruding toward the exit side of the blue light LB. The focal point F2 of the plano-convex lens constituting the collimating element 162 is at least on the -D2 side of the collimating element 162, and is opposite to the +D2 side from which the green light LG is exited from the collimating element 162, and is further on the -D2 side of the light-guiding element 142. The incident surface 162a of the collimating element 162 is in contact with the exit end 142b of the light-guiding element 142. By the collimating element 162 being in contact with the exit end 142b, the green light LG exited from the exit end 142b of the light-guiding element 142 is taken in to the collimating element 162 to the maximum extent, and loss of the green light LG is suppressed. However, the parallelizing element 162 may be an optical lens other than a plano-convex lens that can parallelize the incident green light LG, and may be disposed at an appropriate interval from the light guide element 142 in the D2 direction.

[0047] The focal length f2 of the collimating element 162 corresponds to a second focal length, and is longer than the length g2 in the direction D2 from the incident end 142a to the exit end 142b of the light guide element 142. The length g2 corresponds to the second length.

[0048] As shown in detail in FIG. 2, a light ray Lg1, which is a part of the green light LG incident on the light guide element 142, does not enter the reflecting surface 142r even once, and propagates directly from the incident end 142a to the exit end 142b. A light ray Lg2, which is a part of the remaining green light LG incident on the light guide element 142, enters the reflecting surface 142r once from the incident end 142a, is reflected by the reflecting surface 142r, and then reaches the exit end 142b. The resultant vector VG of the light rays Lg1 and Lg2 emitted from the exit end 142b to the +D2 side, ignoring the action of the parallelizing element 162, is represented by a dashed line. When the resultant vector VG at the exit end 142b is extended from the base end on the -D2 side in parallel with the resultant vector VG to the -D2 side, the focal point F2 is located at the position where it intersects with the center line and optical axis including the D1 direction and D3 direction of the parallelizing element 162 and the light guide element 142. As described above, the green light LG propagating inside the light guide element 142 has many paths other than the paths of the light rays Lg1 and Lg2. When the resultant vector of the multiple light rays contained in the green light LG emitted from the emission end 142b to the +D2 side is extended to the -D2 side assuming that the action of the collimating element 162 is ignored, the positions where the parallelizing element 162 intersects with the center line and the optical axis of the light guide element 142 do not fit strictly at one point, but are scattered within a region of a small width in the D2 direction, including the focus F2 caused by the resultant vector VG. As a result, the focus F2 of the plano-convex lens of the collimating element 162 has a slight spread in the D2 direction, but macroscopically forms one point.

[0049] As in the green light emitting unit 102, in the above-mentioned blue light emitting unit 101, when the resultant vector of multiple light rays contained in the blue light LB emitted from the emission end 141b to the +D1 side is extended to the -D1 side assuming that the action of the collimating element 161 is ignored, the positions at which the collimating element 161 and the center line and the optical axis of the light guiding element 141 intersect do not fit strictly at one point, but are scattered within an area of ​​a small width in the D1 direction. As a result, the focal point F1 of the plano-convex lens of the collimating element 161 has a slight spread in the D1 direction, but macroscopically forms one point.

[0050] Since the focal length f2 of the collimating element 162 is set on the -D2 side of the light guide element 142 and longer than the length g2 of the light guide element 142 based on the position of the focus F2 based on the above-mentioned principle, the multiple light rays included in the green light LG are efficiently collimated in the D2 direction as shown by the thick line. Note that, although the relationship between the focal length f2 of the collimating element 162 and the length g2 of the light guide element 142 and the actions resulting from the focal length f2 and the length g2 have been described with reference to Fig. 2, the description also applies similarly to the relationship between the focal length f1 of the collimating element 161 of the blue light emitting unit 101 and the length g1 of the light guide element 141 and the actions resulting from the focal length f1 and the length g1.

[0051] Specifically, the focal length f2 of the collimating element 162 is preferably 1.1 times or more the length g2 of the light-guiding element 142. It is more preferable that the focal length f2 is 1.1 times or more the length g2 and 2.0 times or less the length g1. By setting the focal length f2 within the above-mentioned range, the green light LG emitted from the light source 122 is efficiently collimated, and the utilization efficiency of the green light LG is improved. The preferable range of the focal length f2 has also been confirmed by a numerical simulation based on the configuration of the green light emitting unit 102 and ray tracing.

[0052] If the focal length f2 of the collimating element 162 is shorter than 1.1 times the length g2 of the light guide element 142, the illumination range of the green light LG emitted from the collimating element 162 is excessively reduced, and when the image light is converted by the downstream light modulation element 182 and then projected and enlarged and displayed on the screen SC, there is a possibility that a part of the original image will not be displayed. On the other hand, if the focal length f2 is longer than 2.0 times the length g2, a part of the green light LG emitted from the collimating element 162 will not enter the light modulation element 182 arranged downstream of the collimating element 162. As a result, there is a possibility that the utilization efficiency of the green light LG will decrease.

[0053] 1 to 3, the incident-side polarizing element 172 is provided on the optical path of the green light LG emitted from the collimating element 162, and is disposed on the +D2 side of the collimating element 162 and at a position overlapping with the collimating element 162 in the D1 and D3 directions. The incident-side polarizing element 172 is in contact with the light modulation element 182 from the +D2 side, for example, but may be disposed at an appropriate interval from the light modulation element 182 in the D2 direction.

[0054] The incident side polarizing element 172 corresponds to a second polarizing element, and emits a predetermined polarized light of the green light LG emitted from the parallelizing element 162 to the +D2 side along the D2 direction. The predetermined polarized light corresponds to the second polarized light component, for example, S-polarized light. The incident side polarizing element 172 is, for example, a reflective polarizing plate having a plate surface parallel to a plane including the D1 direction and the D3 direction. The incident side polarizing element 172 transmits a portion of the incident green light LG that includes the predetermined polarized light to the +D2 side, and reflects the other portion of the green light LG to the -D2 side.

[0055] As shown in detail in FIG. 3, the green light LG emitted from the light source 122 is randomly polarized light including at least P-polarized light and S-polarized light. The green light LGS, which is an S-polarized component of the green light LG emitted from the light source 122, and the green light LGP, which is a P-polarized component of the green light LG, pass through the light guide element 142, and the illuminance distribution is uniformized by the light guide element 142 in a plane including the D1 direction and the D3 direction, and the green light LGS and LGP are emitted to the +D2 side of the light guide element 142. The green lights LGS and LGP pass through the parallelizing element 162 and are parallelized by the parallelizing element 162. The parallelized green lights LGS and LGP enter the incident side polarizing element 172 from the -D2 side. The green light LGS passes through the incident side polarizing element 172 and is emitted to the +D2 side of the incident side polarizing element 172. The green light LGP is reflected by the incident surface 172a of the incident side polarizing element 172 and is emitted to the -D2 side of the incident side polarizing element 172.

[0056] The green light LGP reflected from the incident side polarizing element 172 to the -D2 side passes through the collimating element 162 and the light guide element 142 in sequence, proceeds along the D2 direction to the -D2 side, is collected in a plane including the D1 direction and the D3 direction, and enters the phosphor 124 of the light source 122 from the +D2 side. The phosphor 124 is re-excited by the green light LGP emitted from the incident side polarizing element 172 to the -D2 side, and emits the green light LG including the green light LGS and LGP from the emission surface 124a to the +D2 side again. Since the incident side polarizing element 172 is composed of a reflective polarizing plate, the polarized light of the green light LG that does not pass through the incident side polarizing element 172 re-enters the phosphor 124 of the light source 122 and contributes to the excitation and light emission of the phosphor 124. As a result, the utilization efficiency of the green light LG in the green light emitting unit 102 and the projector 301 is improved.

[0057] The light modulation element 182 is provided on the optical path of the green light LG emitted from the incident-side polarizing element 172, and is disposed on the +D2 side of the incident-side polarizing element 172 at a position overlapping with the incident-side polarizing element 172 in the D1 and D3 directions. The light modulation element 182 corresponds to a second light modulation element, and modulates the green light LG emitted from the incident-side polarizing element 172 based on image information transmitted from an image forming device such as a computer (not shown) connected to the light modulation element 182 from the outside.

[0058] The light modulation element 182 is, for example, a transmissive liquid crystal panel. The liquid crystal panel constituting the light modulation element 182 has a plurality of pixels (not shown). Each pixel is provided with a switching element. The switching element is, for example, a TFT. An electrical signal corresponding to the brightness of the green light at the relative position of each pixel on the modulation surface of the light modulation element 182 in the image projected by the projector 301 is supplied to the switching element of each pixel. Each pixel modulates the vibration direction of the green light LG incident from the incident side polarizing element 172 by the operation of the switching element corresponding to the aforementioned electrical signal, and generates green image light IG. The image light IG corresponds to the second light. The light modulation element 182 emits the image light IG generated by the liquid crystal panel to the +D2 side along the D2 direction.

[0059] The exit side polarizing element 176 is provided on the optical path of the image light IG exiting from the light modulation element 182, and is disposed on the +D2 side of the light modulation element 182 and at a position overlapping with the light modulation element 182 in the D1 direction and the D3 direction. The exit side polarizing element 176 is in contact with the light modulation element 182 from the +D2 side, for example, but may be disposed at an appropriate interval from the light modulation element 182 in the D2 direction. The exit side polarizing element 176 corresponds to a fifth polarizing element, and emits a predetermined polarized light of the image light IG exiting from the light modulation element 182 to the +D2 side along the D2 direction. The predetermined polarized light corresponds to the fifth polarized component, and is, for example, P polarized light. The exit side polarizing element 176 is, for example, a reflective polarizing plate or an absorptive polarizing plate having a plate surface parallel to a plane including the D1 direction and the D3 direction. The exit side polarizing element 176 transmits a portion of the incident image light IG that contains a predetermined polarization to the +D2 side, and reflects the other portion of the image light IG to the -D2 side.

[0060] 1, the red light emitting portion 103 is disposed on the +D1 side of the green light emitting portion 102, and is disposed in a region overlapping with the blue light emitting portion 101 in the D2 and D3 directions. The red light emitting portion 103 emits red light LR. The red light LR emitted from the red light emitting portion 103 travels toward the -D1 side along the D1 direction.

[0061] The red light emitting unit 103 includes a light source 123, a light guide element 143, and a collimating element 163. The light source 123 is supported by the substrate 112. The light source 123 is provided on a plate surface on the -D1 side of the plate surface of the substrate 113 that is parallel to a plane including the D2 and D3 directions. The light emitting surface of the light source 123 is disposed approximately parallel to the plane including the D2 and D3 directions, and is a surface on the opposite side in the D1 direction to a surface of the light source 123 that is in contact with the plate surface on the +D2 side of the substrate 113. The light source 123 corresponds to a third light source, and emits red light LR in a red wavelength band in the visible wavelength band. The red wavelength band is, for example, a wavelength band of 610 nm to 700 nm.

[0062] The light source 123 is composed of, for example, an LED that emits red light LR. The light source 123 may be composed of one LED or may be composed of a plurality of LEDs. When the light source 123 is composed of a plurality of LEDs, the plurality of LEDs are arranged in an area occupied by the light source 123 in a plane including the D2 direction and the D3 direction.

[0063] The substrate 113 is made of, for example, a metal, and also functions as a heat dissipation member that receives heat from the light source 123 that emits the red light LR and dissipates the heat to the external space.

[0064] The light guide element 143 is provided on the optical path of the red light LR emitted from the light source 123, and is disposed on the -D1 side of the light source 123 and at a position overlapping with the light source 123 in the D2 and D3 directions. The light guide element 143 corresponds to a third light guide element, and has an incident end 143a on the +D1 side in the D1 direction, an exit end 143b on the -D1 side, and a side surface 143s and a reflecting surface 143r extending between the incident end 143a and the exit end 143b in the D1 direction. The incident end 143a corresponds to a third incident end, and extends parallel to a plane including the D2 and D3 directions. The shape of the incident end 143a when viewed from the D1 direction is the same as the shape of the light emitting surface of the light source 123 when viewed from the same direction, and is, for example, rectangular. The size of the incident end 143a in the plane including the D2 direction and the D3 direction may be equivalent to the size of the light emitting surface of the light source 123 in the plane including the D2 direction and the D3 direction, but is preferably moderately larger than the size of the light emitting surface of the light source 123 in the plane including the D2 direction and the D3 direction. The exit end 143b corresponds to the third exit end, spreads parallel to the plane including the D2 direction and the D3 direction, and is larger than the incident end 143a. The shape of the exit end 143b when viewed from the D1 direction is similar to the modulation surface of the light modulation element 183 when viewed from the same direction, and is, for example, rectangular. The size of the exit end 143b in the plane including the D2 direction and the D3 direction is equivalent to the size of the modulation surface of the light modulation element 183 in the plane including the D2 direction and the D3 direction. The side surface 143s and the reflecting surface 143r connect the peripheral portion of the incident end 143a and the peripheral portion of the exit end 143b in the D1 direction.

[0065] The red light LR emitted from the light source 123 enters the light guide element 143 from the incident end 143a. In the light guide element 143, the area surrounded by the incident end 143a, the exit end 143b, and the reflecting surface 143r is the area through which the red light LR propagates. The size of the area surrounded by the incident end 143a, the exit end 143b, and the reflecting surface 143r in the plane including the D2 and D3 directions increases as it progresses from the +D1 side to the -D1 side in the D1 direction. In addition, the shape of the area surrounded by the incident end 143a, the exit end 143b, and the reflecting surface 143r in the plane including the D2 and D3 directions changes from the shape of the light emitting surface of the light source 123 when viewed from the D1 direction to the shape of the modulation surface of the light modulation element 183 as it progresses from the +D1 side to the -D1 side.

[0066] A side surface 143s of the light guide element 143 and a reflecting surface 143r provided on the side surface 143s as described below form a predetermined angle with respect to a virtual line VX perpendicular to the incident end 143a and the optical axis, and move away from the virtual line in a plane including the D2 and D3 directions as moving from the -D2 side to the +D2 side. The green light LG incident on the light guide element 142 propagates from the -D2 side to the +D2 side within a region surrounded by the incident end 143a, the exit end 143b, and the reflecting surface 143r.

[0067] When the shape of the modulation surface of the light modulation element 183 is rectangular when viewed in the D1 direction, the shape of the light emitting surface of the light source 123 when viewed in the D1 direction is also rectangular. In this case, the predetermined angle α that the side surface 143s including the short side of the rectangle and the reflecting surface 143r make with the virtual line and the optical axis is preferably within a range of 7° to 22°. The predetermined angle β that the side surface 143s including the long side of the rectangle and the reflecting surface 143r make with the virtual line and the optical axis is preferably within a range of 14° to 36°.

[0068] A part of the red light LR incident on the light guide element 143 forms an angle smaller than a predetermined angle with respect to the virtual axis and the optical axis, does not enter the reflecting surface 143r even once, and propagates directly from the incident end 143a to the exit end 143b. A remaining part of the red light LR incident on the light guide element 143 forms an angle equal to or larger than a predetermined angle with respect to the virtual axis and the optical axis, enters the reflecting surface 143r from the incident end 143a one or more times, is reflected by the reflecting surface 143r, and then reaches the exit end 143b. The path of the ray of the red light LR in the area surrounded by the incident end 143a, the exit end 143b, and the reflecting surface 143r varies depending on the angle of incidence on the incident end 143a, and extends over a plurality of paths that are reflected by the reflecting surface 143r a different number of times. As a result, the illuminance distribution of the red light LR propagating through the region surrounded by the incident end 143a, the exit end 143b, and the reflecting surface 143r is uniformized within a plane including the D2 and D3 directions. That is, the light guide element 143 uniforms the illuminance distribution of the incident red light LR within a plane including the D2 and D3 directions. The red light LR with the uniform illuminance distribution is emitted from the exit end 143b to the -D1 side.

[0069] The light guide element 143 is a hollow reflector made of a plate-like member made of a transparent material such as optical glass, similar to the light guide elements 141 and 142. When viewed along the D1 direction, the end on the +D1 side of the frame of the reflector has the same shape and size as the entrance end 143a and the light emitting surface of the light source 123, and is formed, for example, in a rectangular frame shape. The end on the -D1 side of the frame of the reflector has the same shape and size as the exit end 143b and the modulation surface of the light modulation element 183, and is formed, for example, in a rectangular frame shape of a different size from the end on the +D1 side.

[0070] The reflector of the light guide element 143 is configured by connecting the sides corresponding to the legs of four plate-like members having a trapezoid shape. The length of the side parallel to the D2 direction or the D3 direction on the +D1 side corresponding to the upper base of the four plate-like members is set according to the entrance end 143a and the size of the light emitting surface of the light source 123 in the D2 direction or the D3 direction. The length of the side parallel to the D2 direction or the D3 direction on the -D1 side corresponding to the lower base of the four plate-like members is set according to the exit end 143b and the size of the modulation surface of the light modulation element 183 in the D2 direction or the D3 direction.

[0071] In the reflector of the light-guiding element 143, in order to increase the reflectance of the red light LR incident from the incident end 143a into the light-guiding element 143 near the side surface 143s, a reflective film 253 made of a dielectric multilayer film or the like is provided on a plate surface opposite to the side surface 143s in the plate member constituting the reflector, i.e., on the plate surface facing the internal space of the plate member. A part of the red light LR incident from the incident end 143a into the internal space of the reflector of the light-guiding element 143 is reflected by the reflective film 253 and travels toward the +D1 side.

[0072] The intensity of the red light LR reflected by the reflective film 253 may depend on the angle of incidence of the red light LR incident on the reflective film 253. When the reflective film 253 is made of a dielectric multilayer film, the incidence angle dependency of the intensity of the red light LR emitted from the reflective film 253 changes depending on parameters such as the refractive index, thickness, and number of films of the multiple films included in the dielectric multilayer film. As described above, the reflective film 253 is designed and the parameters of the dielectric multilayer film are appropriately determined so that, for example, when the angle α is within the range of 7° to 22° and the angle β is within the range of 14° to 36°, the incidence angle of the red light LR at which the intensity of the red light LR emitted from the reflection surface 143r and the reflective film 253 is the highest is within the range of 60° to 90°. The relationship between the angle of incidence of the red light LR to the reflective film 253 and the intensity of the red light LR emitted from the reflective film 253 is also obtained by a numerical simulation based on the configuration of the red light emitting unit 103 and ray tracing.

[0073] The collimating element 163 is provided on the optical path of the red light LR emitted from the light guide element 143, and is disposed on the -D1 side of the light guide element 143 and at a position overlapping with the light guide element 143 in the D2 direction and the D3 direction. The collimating element 163 corresponds to a third collimating element, and collimates the red light LR emitted from the light guide element 143 along the D1 direction.

[0074] The collimating element 163 is, for example, a plano-convex lens, and has an entrance surface made of a flat surface perpendicular to the D1 direction, and an exit surface made of a convex curved surface protruding toward the exit side of the red light LR. The focal point of the plano-convex lens constituting the collimating element 163 is at least on the +D1 side of the collimating element 163, and is opposite to the -D1 side from which the red light LR is exited from the collimating element 163, and is further on the +D1 side of the light-guiding element 143. The entrance surface of the collimating element 163 is in contact with the exit end 143b of the light-guiding element 143. By the collimating element 163 being in contact with the exit end 143b, the red light LR exited from the exit end 143b of the light-guiding element 143 is taken in to the collimating element 163 to the maximum extent, and loss of the red light LR is suppressed. However, the parallelizing element 163 may be an optical lens other than a plano-convex lens capable of parallelizing the incident red light LR, and may be disposed at an appropriate interval from the light guide element 143 in the D1 direction.

[0075] The focal length f3 of the collimating element 163 corresponds to a third focal length, and is longer than the length g3 in the D1 direction from the incident end 143a to the exit end 143b of the light guide element 143. The length g3 corresponds to a third length.

[0076] Although not shown, in the red light emitting unit 103 as in the green light emitting unit 102, when the resultant vector of multiple light rays contained in the red light LR emitted from the emission end 143b to the -D1 side is extended to the +D1 side assuming that the action of the collimating element 163 is ignored, the positions at which the parallelizing element 163 and the center line and the optical axis of the light guiding element 143 intersect do not fit strictly at one point, but are scattered within an area of ​​a small width in the D1 direction. As a result, the focal point F3 of the plano-convex lens of the collimating element 163 has a slight spread in the D1 direction, but macroscopically forms one point.

[0077] Since the focal length f3 of the parallelizing element 163 is set on the +D1 side of the light-guiding element 143 in consideration of the position of the focus F3 and is longer than the length g3 of the light-guiding element 143, the multiple light rays contained in the red light LR are efficiently parallelized in the D1 direction.

[0078] Specifically, the focal length f3 of the collimating element 163 is preferably 1.1 times or more the length g3 of the light-guiding element 143. It is more preferable that the focal length f3 is 1.1 times or more and 2.0 times or less the length g3. By setting the focal length f3 within the above-mentioned range, the red light LR emitted from the light source 123 is efficiently collimated, and the utilization efficiency of the red light LR is improved. The preferable range of the focal length f3 has also been confirmed by a numerical simulation based on the configuration of the red light emitting unit 103 and ray tracing.

[0079] When the focal length f3 of the collimating element 163 is shorter than 1.1 times the length g3 of the light guide element 143, the illumination range of the red light LR emitted from the collimating element 163 is excessively reduced, and when the image light converted by the downstream light modulation element 183 is projected and enlarged and displayed on the screen SC, there is a possibility that a part of the original image will not be displayed. On the other hand, when the focal length f3 is longer than 2.0 times the length g3, a part of the red light LR emitted from the collimating element 163 will not enter the light modulation element 183 arranged downstream of the collimating element 163. As a result, there is a possibility that the utilization efficiency of the red light LR will decrease.

[0080] The incident-side polarizing element 173 is provided on the optical path of the red light LR emitted from the collimating element 163, and is disposed on the -D1 side of the collimating element 163 and at a position overlapping with the collimating element 163 in the D2 and D3 directions. The incident-side polarizing element 173 is in contact with the light modulation element 183 from the +D1 side, for example, but may be disposed at an appropriate interval from the light modulation element 183 in the D1 direction.

[0081] The incident side polarizing element 173 corresponds to a third polarizing element, and emits a predetermined polarized light of the red light LR emitted from the parallelizing element 163 to the -D1 side along the D1 direction. The predetermined polarized light corresponds to a third polarized light component, for example, S-polarized light. The incident side polarizing element 173 is, for example, a reflective polarizing plate having a plate surface parallel to a plane including the D2 direction and the D3 direction. The incident side polarizing element 173 transmits a portion of the incident red light LR that includes the predetermined polarized light to the -D1 side, and reflects the other portion of the red light LR to the +D1 side.

[0082] The red light LR emitted from the light source 123 includes at least P-polarized light and S-polarized light, and is, for example, randomly polarized light. The P-polarized component of the red light LR emitted from the light source 123 passes through the light guide element 143 and the parallelizing element 163 in this order, as described above, passes through the incident-side polarizing element 173, and is emitted toward the -D1 side of the incident-side polarizing element 173. The S-polarized component of the red light LR, like the P-polarized component, passes through the light guide element 143 and the parallelizing element 163 in this order, but is reflected by the incident surface of the incident-side polarizing element 173 and is emitted toward the +D1 side of the incident-side polarizing element 173.

[0083] The light modulation element 183 is provided on the optical path of the red light LR emitted from the incident-side polarizing element 173, and is disposed on the -D1 side of the incident-side polarizing element 173 and at a position overlapping with the incident-side polarizing element 173 in the D2 and D3 directions. The light modulation element 183 corresponds to a third light modulation element, and modulates the red light LR emitted from the incident-side polarizing element 173 based on image information transmitted from an image forming device such as a computer (not shown) connected to the light modulation element 183 from the outside.

[0084] The light modulation element 183 is, for example, a transmissive liquid crystal panel. The liquid crystal panel constituting the light modulation element 183 has a plurality of pixels (not shown). Each pixel includes a switching element. The switching element is, for example, a TFT. An electrical signal corresponding to the brightness of the red light at the relative position of each pixel on the modulation surface of the light modulation element 183 in the image projected by the projector 301 is supplied to the switching element of each pixel. Each pixel modulates the vibration direction of the red light LR incident from the incident side polarizing element 173 by the operation of the switching element corresponding to the electrical signal, and generates red image light IR. The image light IR corresponds to the third light. The light modulation element 183 emits the image light IR generated by the liquid crystal panel to the -D1 side along the D1 direction.

[0085] The exit side polarizing element 177 is provided on the optical path of the image light IR exiting from the light modulation element 183, and is disposed on the -D1 side of the light modulation element 183 and at a position overlapping with the light modulation element 183 in the D2 direction and the D3 direction. The exit side polarizing element 177 is in contact with the light modulation element 183 from the -D1 side, for example, but may be disposed at an appropriate interval from the light modulation element 183 in the D1 direction. The exit side polarizing element 177 corresponds to a sixth polarizing element, and emits a predetermined polarized light of the image light IR exiting from the light modulation element 183 to the -D1 side along the D1 direction. The predetermined polarized light corresponds to a sixth polarized component, and is, for example, P polarized light. The exit side polarizing element 177 is, for example, a reflective polarizing plate or an absorptive polarizing plate having a plate surface parallel to a plane including the D2 direction and the D3 direction. The exit side polarizing element 177 transmits a portion of the incident image light IR that includes a predetermined polarization to the +D2 side, and reflects the other portion of the green light LG to the -D2 side.

[0086] The light combining element 200 is disposed in a region where the optical path of the red image light IR emitted from the emission side polarizing element 175, the optical path of the green image light IG emitted from the emission side polarizing element 176, and the optical path of the red image light IR emitted from the emission side polarizing element 177 intersect. The light combining element 200 combines the image lights IB, IG, and IR emitted from the emission side polarizing elements 175, 176, and 177, and emits the combined light to the +D2 side along the D2 direction.

[0087] The light combining element 200 is, for example, a cross dichroic prism 210. The cross dichroic prism 210 has an incident surface 210c facing the exit surface of the exit side polarizing element 175, an incident surface 210d facing the exit surface of the exit side polarizing element 176, an incident surface 210e facing the exit surface of the exit side polarizing element 177, an exit surface 210b, and two reflective films 211 and 212. The incident surfaces 210c and 210e are parallel to a plane including the D2 direction and the D3 direction, and overlap each other in the D2 direction and the D3 direction. The incident surface 210d and the exit surface 210b are parallel to a plane including the D1 direction and the D3 direction, and overlap each other in the D1 direction and the D3 direction.

[0088] The reflective film 211 is arranged so that, when viewed along the D3 direction, it moves from +D2 side to -D2 side as it moves from -D1 side to +D1 side. The reflective film 212 is arranged so that, when viewed along the D3 direction, it moves from -D2 side to +D2 side as it moves from -D1 side to +D1 side. The reflective films 211 and 212 overlap with the incident surfaces 210c and 210e in the D2 direction, and overlap with the incident surfaces 210b and 210d in the D3 direction. The reflective film 211 reflects light in the blue wavelength band and transmits light in the green and red wavelength bands. The reflective film 212 reflects light in the red wavelength band and transmits light in the blue and green wavelength bands.

[0089] The cross dichroic prism 210 is configured by bonding together the right-angled surfaces of four right-angled prisms with their right-angle apexes aligned with the center position of the light combining element 200 when viewed from the D3 direction. The four right-angled prisms of the cross dichroic prism 210 are formed of a transparent material that transmits light of visible wavelengths. The reflective film 211 is disposed on the right-angled surface of the four right-angled prisms that moves from the +D2 side to the -D2 side as it moves from the -D1 side to the +D1 side as described above, and is configured, for example, of a dielectric multilayer film. The reflective film 212 is disposed on the right-angled surface of the four right-angled prisms that moves from the -D2 side to the +D2 side as it moves from the -D1 side to the +D1 side as described above.

[0090] The P-polarized light of the blue image light IB emitted from the emission-side polarizing element 175 enters the inside of the cross dichroic prism 210 from the incident surface 210c toward the +D1 side along the D1 direction, passes through the reflective film 211, is reflected by the reflective film 212, and proceeds toward the +D2 side. The P-polarized light of the green image light IG emitted from the emission-side polarizing element 176 enters the inside of the cross dichroic prism 210 from the incident surface 210d toward the +D2 side along the D2 direction, passes through the reflective films 211 and 212, and proceeds straight toward the +D2 side. The P-polarized light of the red image light IR emitted from the emission-side polarizing element 177 enters the inside of the cross dichroic prism 210 from the incident surface 210e toward the -D1 side along the D1 direction, passes through the reflective film 212, is reflected by the reflective film 211, and proceeds toward the +D2 side. The image light beams IB, IG, and IR emitted from the reflective films 211 and 212 of the cross dichroic prism 210 to the +D2 side are combined together to generate full-color image light IM. The cross dichroic prism 210 emits the full-color image light IM from the emission surface 210b to the +D2 side along the D2 direction.

[0091] The projection optical system 250 is disposed on the optical path of the image light IM emitted from the light combining element 200. The projection optical system 250 projects the image light IM emitted from the projection optical system 250 onto a screen SC disposed on the +D2 side, and enlarges and displays the image transmitted from the image forming device to the light modulation elements 181, 182, and 183 on the screen SC.

[0092] The projection optical system 250 is composed of, for example, one or more optical lenses arranged along the direction D2. The optical lenses include, for example, a plano-convex lens, a plano-concave lens, a biconvex lens, a biconcave lens, a meniscus lens, an aspheric lens, a free-form lens, and the like.

[0093] The projector 301 of the present embodiment described above includes a light source (first light source) 121, a light source (second light source) 122, a light source (third light source) 123, a light guide element (first light guide element) 141, a light guide element (second light guide element) 142, a light guide element (third light guide element) 143, a parallelizing element (first parallelizing element) 161, a parallelizing element (second parallelizing element) 162, a parallelizing element (third parallelizing element) 163, a light modulation element (first light modulation element) 181, a light modulation element (second light modulation element) 182, a light modulation element (third light modulation element) 183, a light combining element 200, and a projection optical system 250. The light source 121 emits blue light (first light) LB in a blue wavelength band (first wavelength band). The light source 122 emits green light (second light) LG in a green wavelength band (second wavelength band) different from the blue wavelength band. The light source 123 emits red light (third light) LR in a red wavelength band (third wavelength band) different from the blue wavelength band and the green wavelength band. The light guide element 141 has an entrance end (first entrance end) 141a into which the blue light LB emitted from the light source 121 is incident and an exit end (first exit end) 141b from which the blue light LB is emitted, and uniforms the illuminance (in-plane illuminance) in a plane including the D2 direction and the D3 direction of the blue light LB. The light guide element 142 has an entrance end (second entrance end) 142a into which the green light LG emitted from the light source 122 is incident and an exit end (second exit end) 142b from which the green light LG is emitted, and uniforms the illuminance (in-plane illuminance) in a plane including the D1 direction and the D3 direction of the green light LG. The light guide element 143 has an entrance end (third entrance end) 143a into which the red light LR emitted from the light source 123 is incident, and an exit end (third exit end) 143b from which the red light LR is emitted, and uniformizes the illuminance (in-plane illuminance) in a plane including the D1 and D3 directions of the red light LR. The light modulation element (first light modulation element) 181 modulates the blue light LB emitted from the collimating element 161 based on image information. The light modulation element (second light modulation element) 182 modulates the green light LG emitted from the collimating element 162 based on image information. The light modulation element (third light modulation element) 183 modulates the red light LR emitted from the collimating element 163 based on image information. The light combining element 200 combines and emits image light (first light) IB emitted from the light modulation element 181, image light (second light) IG emitted from the light modulation element 182, and image light (third light) IR emitted from the light modulation element 183.The projection optical system 250 projects the image light (light) IM emitted from the light combining element 200. In the projector 301 of this embodiment, the focal length (first focal length) f1 of the collimating element 161 is longer than the length (first length) g1 in the D1 direction from the incident end 141a to the exit end 141b of the light guide element 141. The focal length (second focal length) f2 of the collimating element 162 is longer than the length (second length) g2 in the D2 direction from the incident end 142a to the exit end 142b of the light guide element 142. The focal length (third focal length) f3 of the collimating element 163 is longer than the length (third length) g3 in the D1 direction from the incident end 143a to the exit end 143b of the light guide element 143.

[0094] In the projector 301 of this embodiment, three color lights emitted from the light sources 121, 122, 123, i.e., blue light LB, green light LG, and red light LR, are directly converted into image lights IB, IG, IR by the light modulation elements 181, 182, 183, the image lights IB, IG, IR are combined by the light combining element 200, and the generated full-color image light IM is projected. On the other hand, in a conventional projector, white light is generated, the white light is separated into three color lights by a color separation element or a color separation optical system, each color light is converted into image light by the light modulation element, the image lights are combined into full-color image light by the light combining element, and the full-color image light is projected. In the projector 301 of the present embodiment, since it is not necessary to provide a color combining element or color combining optical system that combines the three color lights into white light, and a color separating element or color separating optical system that separates the white light into three color lights, in the stage preceding the light modulation element corresponding to the three color lights, it is possible to reduce the number of parts and devices, and to reduce the size, compared to conventional projectors. The projector 301 of the present embodiment can be made smaller than conventional projectors.

[0095] In the projector 301 of this embodiment, the focal length f1 of the parallelizing element 161 is longer than the length g1 of the light-guiding element 141, the focal length f2 of the parallelizing element 162 is longer than the length g2 of the light-guiding element 142, and the focal length f3 of the parallelizing element 163 is longer than the length g3 of the light-guiding element 143. Therefore, the parallelism of the blue light LB, green light LG, and red light LR emitted from the light-guiding elements 141, 142, and 143 can be improved, and these colored lights can be efficiently incident on the parallelizing elements 161, 162, and 163, thereby improving the utilization efficiency of the colored lights.

[0096] In the projector 301 of this embodiment, the cross-sectional shape of the light guide elements 141 and 143 perpendicular to the optical axis and the D1 direction is rectangular, and the cross-sectional shape of the light guide element 142 perpendicular to the optical axis and the D2 direction is rectangular.

[0097] In the projector 301 of this embodiment, it is possible to easily generate blue light LB, green light LG, and red light LR that are rectangular and have uniform illuminance in a plane perpendicular to the optical axis of the colored light by the light guide elements 141, 142, and 143. According to the projector 301 of this embodiment, it is possible to easily generate colored light that matches the rectangular modulation surfaces of the light modulation elements 181, 182, and 183.

[0098] The projector 301 of this embodiment further includes an incident side polarizing element (first polarizing element) 171, an incident side polarizing element (second polarizing element) 172, and an incident side polarizing element (third polarizing element) 173. The incident side polarizing element 171 is disposed between the parallelizing element 161 and the light modulation element 181, and transmits a part of the blue light LB having an S polarized component (first polarized component), and reflects the other part of the blue light LB, the P polarized component. In the projector 301 of this embodiment, the incident side polarizing element 172 is disposed between the parallelizing element 162 and the light modulation element 182, and transmits a part of the green light LG having an S polarized component (second polarized component), and reflects the other part of the green light LG, the P polarized component. The incident side polarizing element 173 is disposed between the parallelizing element 163 and the light modulation element 183, and transmits a part of the red light LR having an S polarized component (third polarized component), and reflects the other part of the red light LR, the P polarized component. In the projector 301 of this embodiment, another portion of the blue light LB enters the light guide element 141 and travels toward the light source 121. Another portion of the green light LG enters the light guide element 142 and travels toward the light source 122. Another portion of the red light LR enters the light guide element 143 and travels toward the light source 123.

[0099] In the projector 301 of the present embodiment, the other parts of the blue light LB, the green light LG, and the red light LR reflected by the incident-side polarizing elements 171, 172, and 173 and emitted from the incident-side polarizing elements 171, 172, and 173 can be made incident on the light sources 121, 122, and 123. When the light source 122 among the light sources 121, 122, and 123 has a phosphor 124, for example, the other part of the green light LG toward the light source 122 is incident on the phosphor 124 and contributes to the excitation of the phosphor 124. When the substrates 111, 112, and 113 of the light sources 121, 122, and 123 are reflective, the other parts of the blue light LB, the green light LG, and the red light LR toward the light sources 121, 122, and 123 are reflected by the substrates 111, 112, and 113, re-enter the light guide elements 141, 142, and 143, and are used. According to the projector 301 of this embodiment, other portions of the blue light LB, green light LG, and red light LR reflected by the incident side polarizing elements 171, 172, and 173 are re-entered into the light-guiding elements 141, 142, and 143, thereby improving the utilization efficiency of the blue light LB, green light LG, and red light LR.

[0100] In the projector 301 of this embodiment, the cross-sectional area including the D2 and D3 directions of the exit end 141b of the light guide element 141 is larger than the cross-sectional area including the same directions of the entrance end 141a of the light guide element 141. The cross-sectional area including the D1 and D3 directions of the exit end 142b of the light guide element 142 is larger than the cross-sectional area including the same directions of the entrance end 142a of the light guide element 142. The cross-sectional area including the D2 and D3 directions of the exit end 143b of the light guide element 143 is larger than the cross-sectional area including the same directions of the entrance end 143a of the light guide element 143.

[0101] FIG. 4 is a schematic diagram of the green light emission unit 102, the incident side polarizing element 172, and the light modulation element 182, as an example. Note that in FIG. 3 and FIG. 4, as a modified example of the projector 301 of the present embodiment, the incident side polarizing element 172 is disposed at an interval from the parallelizing element 162 in the D2 direction, and the light modulation element 182 is disposed at an interval from the incident side polarizing element 172. As shown in FIG. 4 and described above, for example, the width w142A of the incident end 142a of the light guide element 142 in the D1 direction is set according to the width w122 of the light emitting surface 122a of the light source 122 in the D1 direction. The width w142B of the exit end 142b of the light guide element 142 in the D1 direction is larger than the width w142A of the incident end 142a. Although not shown, the width and cross-sectional area of ​​the emission end 142b of the light guide element 142 in the direction D2 are greater than the width and cross-sectional area of ​​the incidence end 142a in the direction D2.

[0102] In the projector 301 of this embodiment, the illuminance distribution of the blue light LB, green light LG, and red light LR is uniformized and the irradiation area of ​​each color light is expanded before the blue light LB, green light LG, and red light LR enter the light guide elements 141, 142, and 143 from the entrance ends 141a, 142a, and 143a and exit from the exit ends 141b, 142b, and 143b. According to the projector 301 of this embodiment, the size of the surface perpendicular to the optical axis of the blue light LB, green light LG, and red light LR emitted from the light sources 121, 122, and 123 whose light emitting surfaces are smaller than the modulation surfaces of the light modulation elements 181, 182, and 183, that is, the irradiation area, can be easily expanded to match the modulation surfaces of the light modulation elements 181, 182, and 183.

[0103] In the projector 301 of this embodiment, the length from the incident end 141a to the exit end 141b of the light guide element 141 is 8 mm or more and 25 mm or less. A second distance from the incident end 142a to the exit end of the light guide element 142 is 8 mm or more and 25 mm or less. The length from the incident end 143a to the exit end 143b of the light guide element 143 is 8 mm or more and 25 mm or less.

[0104] According to the projector 301 of this embodiment, it is possible to improve the extraction efficiency of the blue light LB, green light LG, and red light LR by the light guide elements 141, 142, and 143, and to uniformize the illuminance distribution of the blue light LB, green light LG, and red light LR.

[0105] In the projector 301 of this embodiment, the length g1 of the light guide element 141 and the focal length f1 of the collimating element 161 are such that 1.1×g1≦f1≦2.0×g1. The length g2 of the light guide element 142 and the focal length f2 of the collimating element 162 are such that 1.1×g2≦f2≦2.0×g2. The length g3 of the light guide element 143 and the focal length f3 of the collimating element 163 are such that 1.1×g3≦f3≦2.0×g3.

[0106] According to the projector 301 of this embodiment, the blue light LB, green light LG, and red light LR emitted from the light-guiding elements 141, 142, and 143 can be more efficiently incident on the parallelizing elements 161, 162, and 163, thereby improving the utilization efficiency of the blue light LB, green light LG, and red light LR.

[0107] In the projector 301 of this embodiment, the focus F1 of the collimating element 161 is located on the -D1 side of the light source 121, that is, on the opposite side to the emission side of the blue light LB of the light source 121. The focus F2 of the collimating element 162 is located on the -D2 side of the light source 122, that is, on the opposite side to the emission side of the green light LG of the light source 122. The focus F3 of the collimating element 163 is located on the +D2 side of the light source 123, that is, on the opposite side to the emission side of the red light LR of the light source 123.

[0108] According to the projector 301 of this embodiment, the blue light LB, green light LG, and red light LR emitted from the light-guiding elements 141, 142, and 143 can be efficiently incident on the parallelizing elements 161, 162, and 163, thereby improving the utilization efficiency of the blue light LB, green light LG, and red light LR.

[0109] In the projector 301 of this embodiment, when the length g1 of the light guide element 141 is 1, the distance in the D1 direction between the position of the focal point F1 of the collimating element 161 and the light exit surface from which the blue light LB is emitted in the light source 121 is 0.1 or more and 0.5 or less. When the length g2 of the light guide element 142 is 1, the distance in the D2 direction between the position of the focal point F2 of the collimating element 162 and the light emitting surface (light exit surface) 122a from which the green light LG is emitted in the light source 122 is 0.1 or more and 0.5 or less. Refer to FIG. 2. When the length g3 of the light guide element 143 is 1, the distance in the D1 direction between the position of the focal point F3 of the collimating element 163 and the light exit surface from which the red light LR is emitted in the light source 123 is 0.1 or more and 0.5 or less.

[0110] According to the projector 301 of this embodiment, the blue light LB, green light LG, and red light LR that are eclipsed by the parallelizing elements 161, 162, and 163 and not captured can be reduced, and the utilization efficiency of the blue light LB, green light LG, and red light LR can be improved.

[0111] In the projector 301 of this embodiment, the light guide elements 141, 142, and 143 are made of glass such as optical glass or metallic glass.

[0112] As described above, in the projector 301 of this embodiment, the light guide elements 141, 142, and 143 are configured with plate-like members made of a transparent material containing glass such as optical glass. According to the projector 301 of this embodiment, the heat dissipation property and heat resistance of the light guide elements 141, 142, and 143 can be improved.

[0113] As a modified example of the projector 301 of the present embodiment, the plate-like members constituting the light guide elements 141, 142, and 143 may be made of metal. That is, the reflectors of the light guide elements 141, 142, and 143 may be made of a plate-like member made of a reflective material such as a metal material that reflects the blue light LB, the green light LG, and the red light LR, for example. In this case, similar to the case where a reflective film is provided on the plate surface facing the internal space of the plate-like member made of a transparent material, the plate surface facing the internal space of the reflector in the plate-like member acts as the reflection surface 141r, 142r, and 143r. A part of each of the blue light LB, the green light LG, and the red light LR that enter the internal space of the reflector of the light guide elements 141, 142, and 143 from the entrance end 141a, 142a, and 143a is reflected by the plate surface facing the internal space of the reflector in the plate-like member, and travels along the optical axis. In the modified example of the projector 301 of this embodiment as well, the heat dissipation properties and heat resistance of the light guide elements 141, 142, and 143 can be improved.

[0114] In the projector 301 of this embodiment, the light guide elements 141, 142, and 143 are hollow, and reflective films 251, 252, and 253 are provided on the surfaces (inner surfaces) of the plate-like members constituting the light guide elements 141, 142, and 143 that face the internal space.

[0115] In the projector 301 of this embodiment, a portion of each of the blue light LB, green light LG, and red light LR incident on the light guide elements 141, 142, and 143 is specularly reflected by the reflective films 251, 252, and 253, and propagates through the internal space of the light guide elements 141, 142, and 143. According to the projector 301 of this embodiment, the loss of the blue light LB, green light LG, and red light LR inside the light guide elements 141, 142, and 143 can be reduced.

[0116] As another modification of the projector 301 of the present embodiment, the light guide elements 141, 142, and 143 may be solid and made of a transparent material such as optical glass. In this case, the plate surfaces of the reflectors constituting the light guide elements 141, 142, and 143 facing the external space, i.e., the side surfaces 141s, 142s, and 143s, act as the reflecting surfaces 141r, 142r, and 143r. A part of each of the blue light LB, the green light LG, and the red light LR incident on the reflectors of the light guide elements 141, 142, and 143 from the incident ends 141a, 142a, and 143a is totally reflected by the reflecting surfaces 141r, 142r, and 143r facing the external space of the reflectors, and travels along the optical axis. Furthermore, the light guide elements 141, 142, and 143 may be solid and made of a transparent material such as optical glass, and the reflective films 251, 252, and 253 may be provided on the side surfaces 141s, 142s, and 143s. In this other modified example of the projector 301 of the present embodiment, the loss of the blue light LB, the green light LG, and the red light LR inside the light guide elements 141, 142, and 143 can also be reduced.

[0117] In the projector 301 of this embodiment, when viewed along the optical axis of the collimating element 161, that is, when the collimating element 161 is viewed along the D1 direction, the collimating element 161 covers the exit end 141b of the light guide element 141 from the +D1 side. When viewed along the optical axis of the collimating element 162, that is, when the collimating element 162 is viewed along the D2 direction, the collimating element 162 covers the exit end 142b of the light guide element 142 from the +D2 side. When viewed along the optical axis of the collimating element 163, that is, when the collimating element 163 is viewed along the D1 direction, the collimating element 163 covers the exit end 143b of the light guide element 143 from the -D1 side.

[0118] According to the projector 301 of this embodiment, the blue light LB, green light LG, and red light LR that are emitted from the emission ends 141b, 142b, and 143b of the light-guiding elements 141, 142, and 143 and are blocked by the parallelizing elements 161, 162, and 163 and not captured can be reduced, thereby improving the utilization efficiency of the blue light LB, green light LG, and red light LR.

[0119] As another variant of projector 301 of this embodiment, light-guiding elements 141, 142, and 143 may be hollow, with at least a portion of collimating element 161 housed in light-guiding element 141, at least a portion of collimating element 162 housed in light-guiding element 142, and at least a portion of collimating element 163 housed in light-guiding element 143.

[0120] In the above-described modified example of the projector 301 of this embodiment, the parallelizing elements 161, 162, 163 may be configured as plano-convex lenses having a flat surface and a convex curved surface protruding toward the incident side of the blue light LB, green light LG, and red light LR, or as biconvex lenses having convex curved surfaces protruding toward the incident side and the exit side of the blue light LB, green light LG, and red light LR.

[0121] 5 and 6 are schematic diagrams of the green light emission unit 102 in another modified example of the projector 301 of this embodiment. In the modified example shown in FIG. 5, a light guide element 146 is provided instead of the light guide element 142, and the light guide element 146 is solid and made of a transparent material. In the modified example shown in FIG. 5, the emission end 142b of the light guide element 146 is made of a convex curved surface that protrudes toward the -D3 side, i.e., the incident side of the green light LG. In the modified example shown in FIG. 5, a collimating element 166 is disposed instead of the collimating element 162. The collimating element 166 is a plano-convex lens, and has an entrance surface 166a made of a convex curved surface that protrudes toward the -D3 side, i.e., the incident side of the green light LG, and an exit surface 166b that is parallel to a plane including the D1 direction and the D3 direction. The exit surface 166b of the collimating element 166 is in contact with the exit end 146b opposite to the entrance end 146a of the light guide element 146 in the D2 direction, and is disposed substantially in the same manner as a part of the entrance side of the green light LG in the collimating element 166 is accommodated in the light guide element 146. According to the modification shown in FIG. 5, the green light LG exited from the exit end 146b of the light guide element 146 can be efficiently taken into the collimating element 166, and the green light LG that is vignetted by the collimating element 166 and not taken in can be reduced as much as possible, thereby improving the utilization efficiency of the green light LG. The configuration shown in FIG. 5 is applicable to the blue light exit section 101 and the red light exit section 103 of the projector 301 of this embodiment.

[0122] In the modification shown in Fig. 6, the light guide element 142 is hollow, a collimating element 166 is disposed instead of the collimating element 162, and a part of the incident side of the collimating element 162 for the green light LG is accommodated in the internal space of the light guide element 142. According to the modification shown in Fig. 6, the green light LG emitted from the emission end 142b of the light guide element 142 is efficiently taken into the collimating element 166 on the -D2 side, and the green light LG that is vignetted by the collimating element 166 and not taken in is reduced as much as possible, thereby improving the utilization efficiency of the green light LG. The configuration shown in Fig. 6 can also be applied to the blue light emission section 101 and the red light emission section 103 of the projector 301 of this embodiment.

[0123] As another modified example of projector 301 of this embodiment, the incident side polarizing element (first polarizing element) of blue light emitting section 101 may be fixed to collimating element 161. The incident side polarizing element (second polarizing element) of green light emitting section 102 may be fixed to collimating element 162. The incident side polarizing element (third polarizing element) of red light emitting section 103 may be fixed to collimating element 163.

[0124] 7 and 8 are schematic diagrams of the green light emitting section 102 in the above-mentioned modified example of the projector 301 of the present embodiment. In the modified example shown in FIG. 7, an incident side polarizing element (second polarizing element) 272 is provided instead of the incident side polarizing element 172. The incident side polarizing element 272 is a reflective polarizing layer or polarizing film having the same effect as the incident side polarizing element 172. The incident side polarizing element 272 is fixed to the parallelizing element 162 by being formed on the exit surface 162b of the parallelizing element 162. According to the modified example shown in FIG. 7, the space between the parallelizing element 162 and the incident side polarizing element 272 can be eliminated, and the green light emitting section 102 and the projector 301 can be prevented from becoming large. According to the modified example shown in FIG. 7, an interface between the air outside the parallelizing element 162 and the incident side polarizing element 272 is not generated, so that the loss of the green light LG can be reduced as much as possible and the utilization efficiency of the green light LG can be increased. The configuration shown in FIG. 7 can also be applied to the blue light emitting section 101 and the red light emitting section 103 of the projector 301 of this embodiment.

[0125] In the modified example shown in FIG. 8, an incident side polarizing element 272 is provided in the configuration shown in FIG. 5. The incident side polarizing element 272 is fixed to the parallelizing element 166 by being formed on the flat exit surface 166b of the parallelizing element 166. In the modified example shown in FIG. 8, the space between the parallelizing element 166 and the incident side polarizing element 272 can be eliminated, and the size of the green light emitting unit 102 and the projector 301 can be prevented from increasing. According to the modified example shown in FIG. 7, since an interface between the air outside the parallelizing element 166 and the incident side polarizing element 272 is not generated, the loss of the green light LG can be reduced as much as possible and the utilization efficiency of the green light LG can be increased. The configuration shown in FIG. 8 can also be applied to the blue light emitting unit 101 and the red light emitting unit 103 of the projector 301 of this embodiment.

[0126] 9 is a schematic diagram of the light source 122 and the light guide element 142 of the green light emission unit 102. In the projector 301 of this embodiment, the cross-sectional shape of the light guide elements 141, 142, and 143 is rectangular. When the gradient angle of the side surface including the short side of the light guide elements 141, 142, and 143, that is, the angle with respect to the optical axis, is α, 7°≦α≦22°. When the gradient angle of the side surface including the long side of the light guide elements 141, 142, and 143 is β, 14°≦β≦36°. Reflecting films 251, 252, and 253 are provided on the surfaces (inner surfaces) of the hollow light guide elements 141, 142, and 143 facing the internal space of the plate-like member. As illustrated in FIG. 9, the angle of incidence of light incident on the reflective films 251, 252, and 253 when the reflectance of each of the blue light LB, the green light LG, and the red light LR at the reflective films 251, 252, and 253 is the highest is defined as θ in When θ is 60° or less, in ≦90°.

[0127] In the projector 301 of this embodiment, light is emitted from the light sources 121, 122, and 123 and enters the light guide elements 141, 142, and 143 radially from the entrance ends 141a, 142a, and 143a at a predetermined angle with respect to the optical axis. Since the reflective films 251, 252, and 253 are designed as described above, the blue light LB, green light LG, and red light LR reflected by the reflective films 251, 252, and 253 have high intensities. According to the projector 301 of this embodiment, the loss of the blue light LB, green light LG, and red light LR in the light guide elements 141, 142, and 143 can be reduced as much as possible, and the utilization efficiency of the blue light LB, green light LG, and red light LR can be increased.

[0128] The projector 301 of this embodiment further includes an emission side polarizing element (fourth polarizing element) 175, an emission side polarizing element (fifth polarizing element) 176, and an emission side polarizing element (sixth polarizing element) 177. The emission side polarizing element 175 is disposed between the light modulation element 181 and the light combining element 200, and transmits a part of the image light (light) IB emitted from the light modulation element 181 that has a P polarized component (fourth polarized component), and absorbs the other part of the image light IB other than the P polarized component. The emission side polarizing element 176 is disposed between the light modulation element 182 and the light combining element 200, and transmits a part of the image light (light) IB emitted from the light modulation element 182 that has a P polarized component (fifth polarized component), and absorbs the other part of the image light IB other than the P polarized component. The exit side polarizing element 177 is disposed between the light modulation element 183 and the light combining element 200, and transmits a portion of the image light (light) IR emitted from the light modulation element that has a P polarized component (sixth polarized component), and absorbs the other portion of the image light IR that is not the P polarized component.

[0129] In the projector 301 of this embodiment, the exit side polarizing elements 175, 176, and 177, which are made of, for example, an absorptive polarizing plate or polarizing element, cause the P polarized component of the image light IB, IG, and IR to enter the light combining element 200, and absorb the other part of the image light IB, IG, and IR other than the P polarized component, thereby suppressing return light and stray light due to the other part of the image light IB, IG, and IR to the light modulation elements 181, 182, and 183.

[0130] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0131] For example, in the same manner as in the green light emitting unit 102, the LEDs constituting the light sources 121, 123 in the blue light emitting unit 101 and the red light emitting unit 103 may include a phosphor that is excited by light from the LED body to emit blue light LB and red light LR. Also, the LED of the light source 122 in the green light emitting unit 102 may not have the phosphor 124, and the light source 122 may be constituted by an LED that directly emits green light LG. Also, the polarized components transmitted by the incident-side polarizing plates arranged in the optical paths of the color lights may or may not be common components.

[0132] [Summary of this disclosure] The following is a summary of this disclosure. (Note 1) A first light source that emits a first light in a first wavelength band, a second light source that emits a second light in a second wavelength band different from the first wavelength band, a third light source that emits a third light in a third wavelength band different from the first wavelength band and the second wavelength band, a first light guiding element having a first entrance end into which the first light emitted from the first light source is incident and a first exit end from which the first light is emitted, and which homogenizes an in-plane illuminance of the first light, and a second entrance end into which the second light emitted from the second light source is incident and a second exit end from which the second light is emitted, a second light guide element having a second exit end that emits light and that uniforms an in-plane illuminance of the second light; a third light guide element having a third entrance end into which the third light emitted from the third light source is incident and a third exit end that emits the third light and that uniforms an in-plane illuminance of the third light; a first collimating element that collimates the first light emitted from the first light guide element; a second collimating element that collimates the second light emitted from the second light guide element; a third collimating element that collimates a first light beam emitted from the first collimating element based on image information; a first light modulation element that modulates the first light emitted from the first collimating element based on image information; a second light modulation element that modulates the second light emitted from the second collimating element based on image information; a third light modulation element that modulates the third light emitted from the third collimating element based on image information; a light combining element that combines the first light emitted from the first light modulation element, the second light emitted from the second light modulation element, and the third light emitted from the third light modulation element and emits the combined light; and a projection optical system that projects the light emitted from the light combining element, wherein a first focal length of the first collimating element is longer than a first length from the first incident end to the first exit end, a second focal length of the second collimating element is longer than a second length from the second incident end to the second exit end, and a third focal length of the third collimating element is longer than a third length from the third incident end to the third exit end.

[0133] The configuration of Appendix 1 does not require optical components for generating white light or for separating light into individual colored lights, so the number of components is reduced, the size of a 3-chip projector is prevented from increasing, and a compact projector can be realized.

[0134] (Supplementary Note 2) The projector of Supplementary Note 1, wherein the first light guide element has a rectangular cross-sectional shape, the second light guide element has a rectangular cross-sectional shape, and the third light guide element has a rectangular cross-sectional shape.

[0135] The configuration of Supplementary Note 2 makes it possible to easily generate rectangular illumination light with a uniform illuminance distribution.

[0136] (Supplementary Note 3) The projector of Supplementary Note 1 or Supplementary Note 2, comprising: a first polarizing element disposed between the first parallelizing element and the first light modulation element, transmitting a portion of the first light having a first polarization component and reflecting another portion; a second polarizing element disposed between the second parallelizing element and the second light modulation element, transmitting a portion of the second light having a second polarization component and reflecting the other portion; and a third polarizing element disposed between the third parallelizing element and the third light modulation element, transmitting a portion of the third light having a third polarization component and reflecting the other portion, wherein the other portion of the first light enters the first light guide element, the other portion of the second light enters the second light guide element, and the other portion of the third light enters the third light guide element.

[0137] With the configuration of Supplementary Note 3, the first light, the second light, and the third light reflected by the first polarizing element, the second polarizing element, and the third polarizing element can be made to re-enter the first light guide element, the second light guide element, and the third light guide element, thereby improving the utilization efficiency of the first light, the second light, and the third light.

[0138] (Appendix 4) Any of the projectors of Appendix 1 to Appendix 3, wherein a cross-sectional area of ​​the first exit end is larger than a cross-sectional area of ​​the first entrance end, a cross-sectional area of ​​the second exit end is larger than a cross-sectional area of ​​the second entrance end, and a cross-sectional area of ​​the third exit end is larger than a cross-sectional area of ​​the third entrance end.

[0139] With the configuration of Appendix 4, the size of the irradiation area of ​​the first light, second light, and third light emitted from the first light source, second light source, and third light source can be matched to the size of the modulation surfaces of the first light modulation element, second light modulation element, and third light modulation element, thereby making the illuminance distribution of the first light, second light, and third light uniform and expanded.

[0140] (Appendix 5) Any of the projectors of appendix 1 to appendix 4, wherein a first length from the first entrance end to the first exit end is 8 mm or more and 25 mm or less, a second length from the second entrance end to the second exit end is 8 mm or more and 25 mm or less, and a third length from the third entrance end to the third exit end is 8 mm or more and 25 mm or less.

[0141] The configuration of Supplementary Note 5 can increase the extraction efficiency of the first light, the second light, and the third light, and can achieve good uniformity of the first light, the second light, and the third light.

[0142] (Supplementary Note 6) Any of the projectors according to Supplementary Note 1 to Supplementary Note 5, wherein, when the first length is g1 and the first focal length is f1, 1.1×g1≦f1≦2.0×g1 holds; when the second length is g2 and the second focal length is f2, 1.1×g2≦f2≦2.0×g2 holds; and when the third length is g3 and the third focal length is f3, 1.1×g3≦f3≦2.0×g3 holds.

[0143] In the configuration of Appendix 6, the first light, the second light, and the third light emitted from the first light-guiding element, the second light-guiding element, and the third light-guiding element are efficiently incident on the first collimating element, the second collimating element, and the third collimating element, thereby improving the utilization efficiency of the first light, the second light, and the third light, and making it possible to miniaturize the projector.

[0144] (Supplementary Note 7) Any of the projectors of Supplementary Note 1 to Supplementary Note 6, wherein a focal point of the first parallelizing element is located on the opposite side to the emission side of the first light of the first light source, a focal point of the second parallelizing element is located on the opposite side to the emission side of the second light of the second light source, and a focal point of the third parallelizing element is located on the opposite side to the emission side of the third light of the third light source.

[0145] In the configuration of Appendix 7, the focal lengths of the first collimating element, the second collimating element, and the third collimating element are appropriately positioned on the light incident side, thereby increasing the utilization efficiency of the first light, the second light, and the third light, and enabling the projector to be made smaller.

[0146] (Appendix 8) Any of the projectors according to appendix 1 to appendix 7, wherein when the first length is 1, the distance between the focal position of the first parallelizing element and a light emission surface from which the first light is emitted in the first light source is 0.1 or more and 0.5 or less.

[0147] In the configuration of Supplementary Note 8, the efficiency of using the first light, the second light, and the third light can be improved, and the projector can be made smaller.

[0148] (Supplementary Note 9) The projector according to any one of Supplementary Notes 1 to 8, wherein the first light guide element, the second light guide element, and the third light guide element are made of glass or metal.

[0149] In the configuration of Supplementary Note 9, the heat dissipation and heat resistance of the first light guide element, the second light guide element, and the third light guide element can be improved.

[0150] (Supplementary Note 10) Any of the projectors according to Supplementary Note 1 to Supplementary Note 9, wherein the first light guide element, the second light guide element, and the third light guide element are hollow, and a reflective film is provided on the inner surfaces of the first light guide element, the second light guide element, and the third light guide element.

[0151] In the configuration of Supplementary Note 10, losses of the first light, the second light, and the third light occurring in the first light guide element, the second light guide element, and the third light guide element can be reduced, and the utilization efficiency of the first light, the second light, and the third light can be improved.

[0152] (Supplementary Note 11) Any of the projectors of Supplementary Note 1 to Supplementary Note 10, wherein when viewed along the optical axis of the first parallelizing element, the first parallelizing element covers the first exit end, when viewed along the optical axis of the second parallelizing element, the second parallelizing element covers the second exit end, and when viewed along the optical axis of the third parallelizing element, the third parallelizing element covers the third exit end.

[0153] In the configuration of Appendix 11, the amounts of the first light, the second light, and the third light eclipsed by the first collimating element, the second collimating element, and the third collimating element can be reduced, thereby improving the utilization efficiency of the first light, the second light, and the third light.

[0154] (Supplementary Note 12) Any of the projectors according to Supplementary Note 1 to Supplementary Note 11, wherein the first light guide element, the second light guide element, and the third light guide element are hollow, at least a portion of the first collimating element is housed in the first light guide element, at least a portion of the second collimating element is housed in the second light guide element, and at least a portion of the third collimating element is housed in the third light guide element.

[0155] In the configuration of Supplementary Note 12, the amounts of the first light, the second light, and the third light diverged by the first collimating element, the second collimating element, and the third collimating element can be reduced, and the efficiency of use of the first light, the second light, and the third light can be improved. Also, in the configuration of Supplementary Note 12, the distances between the first light guide element, the second light guide element, and the third light guide element and the first collimating element, the second collimating element, and the third collimating element in the direction along the optical axes of the first light, the second light, and the third light can be reduced, and an increase in the size of the projector can be suppressed.

[0156] (Appendix 13) The projector of Appendix 3, wherein the first polarizing element is fixed to the first parallelizing element, the second polarizing element is fixed to the second parallelizing element, and the third polarizing element is fixed to the third parallelizing element.

[0157] In the configuration of Appendix 13, the distance between the first parallelizing element, the second parallelizing element, and the third parallelizing element and the first polarizing element, the second polarizing element, and the third polarizing element is reduced, thereby reducing loss of the first light, the second light, and the third light, thereby increasing the utilization efficiency of the first light, the second light, and the third light, and also preventing the projector from becoming larger.

[0158] (Supplementary Note 14) The projector of Supplementary Note 5, wherein a cross-sectional shape of the first light guide element is rectangular, a cross-sectional shape of the second light guide element is rectangular, and a cross-sectional shape of the third light guide element is rectangular, and when a gradient angle of a side surface including a short side of the first light guide element, the second light guide element, and the third light guide element is α, 7°≦α≦22°, and when a gradient angle of a side surface including a long side of the first light guide element, the second light guide element, and the third light guide element is β, 14°≦β≦36°, a reflective film is provided on an inner surface of the first light guide element, the second light guide element, and the third light guide element, and when an incident angle of light incident on the reflective film when the reflectance of the reflective film is highest is θin, 60°≦β≦90°.

[0159] In the configuration of Appendix 14, it is possible to reduce loss of the first light, the second light, and the third light that are reflected in the first light-guiding element, the second light-guiding element, and the third light that are emitted from the first exit end, the second exit end, and the third exit end, and to increase the utilization efficiency of the first light, the second light, and the third light.

[0160] (Appendix 15) The projector of Appendix 3, comprising: a fourth polarizing element disposed between the first light modulation element and the light combining element, the fourth polarizing element transmitting a portion of the light output from the first light modulation element having a fourth polarized component and absorbing the remaining portion; a fifth polarizing element disposed between the second light modulation element and the light combining element, the fifth polarizing element transmitting a portion of the light output from the second light modulation element having a fifth polarized component and absorbing the remaining portion; and a sixth polarizing element disposed between the third light modulation element and the light combining element, the sixth polarizing element transmitting a portion of the light output from the third light modulation element having a sixth polarized component and absorbing the remaining portion.

[0161] In the configuration of Appendix 15, a portion of the light emitted from the first light modulation element, the second light modulation element, and the third light modulation element, which has the fourth polarization component, the fifth polarization component, and the sixth polarization component, is incident on the light combining element, and the fourth polarizing element, the fifth polarizing element, and the sixth polarizing element absorb a portion of the light emitted from the first light modulation element, the second light modulation element, and the third light modulation element other than the fourth polarization component, the fifth polarization component, and the sixth polarization component, thereby suppressing return light and stray light to the first light modulation element, the second light modulation element, and the third light modulation element due to the portion of the light other than the fourth polarization component, the fifth polarization component, and the sixth polarization component. [Explanation of symbols]

[0162] 121...light source (first light source), 122...light source (second light source), 123...light source (third light source), 141...light guiding element (first light guiding element), 142...light guiding element (second light guiding element), 143...light guiding element (third light guiding element), 161...parallelizing element (first parallelizing element), 162...parallelizing element (second parallelizing element), 163...parallelizing element (third parallelizing element), 181...light modulation element (first light modulation element), 162...light modulation element (second light modulation element), 163...light modulation element (third light modulation element), 200...light combining element, 301...projector.

Claims

1. a first light source that emits a first light in a first wavelength band; a second light source that emits second light in a second wavelength band different from the first wavelength band; a third light source that emits third light in a third wavelength band different from the first wavelength band and the second wavelength band; a first light guide element having a first incident end into which the first light emitted from the first light source is incident and a first exit end from which the first light is emitted, the first light guide element making an in-plane illuminance of the first light uniform; a second light guide element having a second incident end into which the second light emitted from the second light source is incident and a second exit end from which the second light is exited, the second light guide element making an in-plane illuminance of the second light uniform; a third light guide element having a third incident end into which the third light emitted from the third light source is incident and a third exit end from which the third light is emitted, and which uniformizes an in-plane illuminance of the third light; a first collimating element that collimates the first light emitted from the first light guide element; a second collimating element that collimates the second light emitted from the second light guide element; a third collimating element that collimates the third light emitted from the third light guide element; a first light modulation element that modulates the first light emitted from the first collimating element based on image information; a second light modulation element that modulates the second light emitted from the second collimating element based on image information; a third light modulation element that modulates the third light emitted from the third collimating element based on image information; a light combining element that combines the first light emitted from the first light modulation element, the second light emitted from the second light modulation element, and the third light emitted from the third light modulation element, and outputs the combined light; a projection optical system that projects the light emitted from the light combining element; Equipped with a first focal length of the first collimating element is longer than a first length from the first incident end to the first exit end; a second focal length of the second collimating element is longer than a second length from the second input end to the second output end; a third focal length of the third collimating element is longer than a third length from the third entrance end to the third exit end; projector.

2. The first light guide element has a rectangular cross-sectional shape, The second light guide element has a rectangular cross-sectional shape, The cross-sectional shape of the third light guide element is rectangular. The projector according to claim 1 .

3. a first polarizing element disposed between the first collimating element and the first light modulation element, which transmits a portion of the first light having a first polarization component and reflects another portion of the first light; a second polarizing element disposed between the second collimating element and the second light modulation element, which transmits a portion of the second light having a second polarization component and reflects the other portion; a third polarizing element disposed between the third parallelizing element and the third light modulation element, which transmits a portion of the third light having a third polarization component and reflects the other portion; Equipped with Another portion of the first light is incident on the first light guide element, Another portion of the second light is incident on the second light guide element, Another part of the third light is incident on the third light guide element. The projector according to claim 1 or 2.

4. a cross-sectional area of ​​the first exit end is larger than a cross-sectional area of ​​the first entrance end; a cross-sectional area of ​​the second exit end is larger than a cross-sectional area of ​​the second entrance end; The cross-sectional area of ​​the third exit end is larger than the cross-sectional area of ​​the third entrance end. The projector according to claim 1 or 2.

5. a first length from the first entrance end to the first exit end is 8 mm or more and 25 mm or less; a second length from the second input end to the second output end is 8 mm or more and 25 mm or less; a third length from the third input end to the third output end is 8 mm or more and 25 mm or less; The projector according to claim 1 or 2.

6. When the first length is g1 and the first focal length is f1, 1.1×g1≦f1≦2.0×g1; When the second length is g2 and the second focal length is f2, 1.1×g2≦f2≦2.0×g2 is satisfied; When the third length is g3 and the third focal length is f3, 1.1×g3≦f3≦2.0×g3 is satisfied. The projector according to claim 1 or 2.

7. a focal point of the first collimating element is located on an opposite side to an emission side of the first light of the first light source, a focal point of the second collimating element is located on an opposite side to an emission side of the second light of the second light source, A focal point of the third collimating element is located on the opposite side to the emission side of the third light of the third light source. The projector according to claim 1 or 2.

8. When the first length is 1, a distance between a focal position of the first collimating element and a light exit surface from which the first light is exited in the first light source is 0.1 or more and 0.5 or less. The projector according to claim 7.

9. The first light guide element, the second light guide element, and the third light guide element are made of glass or metal. The projector according to claim 1 or 2.

10. the first light guide element, the second light guide element, and the third light guide element are hollow; A reflective film is provided on an inner surface of the first light guide element, the second light guide element, and the third light guide element. The projector according to claim 1 or 2.

11. When viewed along an optical axis of the first collimating element, the first collimating element covers the first exit end, When viewed along an optical axis of the second collimating element, the second collimating element covers the second exit end, When viewed along the optical axis of the third collimating element, the third collimating element covers the third exit end. The projector according to claim 1 or 2.

12. the first light guide element, the second light guide element, and the third light guide element are hollow; At least a portion of the first parallelizing element is accommodated in the first light guide element; At least a portion of the second parallelizing element is accommodated in the second light guide element, At least a portion of the third parallelizing element is accommodated in the third light guide element. The projector according to claim 1 or 2.

13. the first polarizing element is fixed to the first collimating element; the second polarizing element is fixed to the second collimating element; the third polarizing element is fixed to the third collimating element; The projector according to claim 3 .

14. The first light guide element has a rectangular cross-sectional shape, The second light guide element has a rectangular cross-sectional shape, The third light guide element has a rectangular cross-sectional shape, When a gradient angle of a side surface including a short side of each of the first light guide element, the second light guide element, and the third light guide element is α, 7°≦α≦22° is satisfied; When a gradient angle of a side surface including a long side of each of the first light guide element, the second light guide element, and the third light guide element is β, 14°≦β≦36° is satisfied; A reflective film is provided on an inner surface of the first light guide element, the second light guide element, and the third light guide element, The angle of incidence of light incident on the reflective film when the reflectance of the reflective film is the highest is defined as θ ｉｎ When 60°≦θ ｉｎ ≦90°; The projector according to claim 5 .

15. a fourth polarizing element disposed between the first light modulation element and the light combining element, which transmits a portion of the light having a fourth polarization component out of the light emitted from the first light modulation element and absorbs the other portion; a fifth polarizing element disposed between the second light modulation element and the light combining element, which transmits a portion of the light having a fifth polarization component out of the light emitted from the second light modulation element and absorbs the other portion; a sixth polarizing element disposed between the third light modulation element and the light combining element, which transmits a portion of the light having a sixth polarization component out of the light emitted from the third light modulation element and absorbs the other portion; Equipped with The projector according to claim 3 .

Images