Projector

Abstract

To reduce the number of components to suppress an increase in size in a projector.SOLUTION: A projector includes: a first light source that emits first light; a second light source that emits second light in a wavelength band different from that of the first light; a first light guide element having a first incident end on which the first light from the first light source is incident and a first emission end from which the first light is emitted; a second light guide element having a second incident end on which the second light from the second light source is incident and a second emission end from which the second light is emitted; a first light modulation element that modulates the first light from the first light guide element on the basis of image information; a second light modulation element that modulates the second light from the second light guide element on the basis of the image information; a photosynthetic element that combines and emits the first light from the first light modulation element and the second light from the second light modulation element; and a projection optical system that projects the light emitted from the photosynthetic element. The spectral reflectance of the second light guide element is the same as the spectral reflectance of the first light guide element.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, a projector equipped with three liquid crystal panels as a light modulation device for generating image light of each of the three primary colors, i.e., a three-panel projector, has been known. For example, Patent Document 1 discloses a projector equipped with a light source device having a light source unit and a separation / combination element, an illumination optical system, a color separation / combination optical system, and a projection optical system. The light source unit emits excitation light for a phosphor. The separation / combination element causes a portion of the light emitted from the light source unit to be incident on the phosphor, and causes another portion 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 / combination optical system performs color separation and color combination on the light emitted from the illumination optical system. The projection optical system enlarges and projects the color-combined image light onto an image display surface such as a screen. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-079820 Summary of the Invention [Problem to be solved by the invention]

[0004] In the three-chip projector disclosed in Patent Document 1, after white light is generated by a light source device, the white light is separated into individual colors by a color separation / combination optical system located downstream of the light source device. Therefore, the projector disclosed in Patent Document 1 must further include a color separation / combination optical system in addition to the light source device. This increases the number of components, potentially leading to an increase in the size of the projector. Therefore, measures are needed to reduce the number of components and prevent the projector from becoming too large in three-chip 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 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, 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 emitted, a first light modulation element that modulates the first light emitted from the first light guide element based on image information, a second light modulation element that modulates the second light emitted from the second light guide element based on image information, a light combining element that combines the first light emitted from the first light modulation element and the second light emitted from the second light modulation element and emits the combined light, and a projection optical system that projects the light emitted from the light combining element. The spectral reflectance of the second reflective film is the same as that of the first reflective film. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of a projector according to an embodiment. [Figure 2] 2 is a perspective view of a light guide element of a blue light emitting section of the projector in FIG. 1. FIG. [Figure 3] 3 is a schematic diagram of a plate-like member and a reflective film of the light guide element of FIG. 2. FIG. [Figure 4] 2 is a schematic diagram of a green light emitting section of the projector in FIG. 1. [Figure 5] 2 is a schematic diagram of a green light output section and an incident-side polarizing element of the projector in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0007] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each drawing, the scale of the dimensions of some components may be changed to make the components 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 equipped with 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 output unit 101, a green light output unit 102, a red light output unit 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 of the D1 direction is referred to as the -D1 side, and the side opposite the -D1 side of the D1 direction is referred to as the +D1 side. The 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 of the D2 direction is referred to as the -D2 side, and the side opposite the -D2 side of the D2 direction is referred to as the +D2 side. The 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 toward the +D1 side along the D1 direction.

[0010] The blue light output unit 101 includes a light source 121, a light guide element 141, and a collimating element 161. The light source 121 is supported by a substrate 111. The light source 121 is provided on a +D1-side 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 substantially parallel to the plane including the D2 and D3 directions, and is a surface of the light source 121 opposite in the D1 direction from a surface of the light source 121 that is in contact with the +D1-side surface of the substrate 111. The light source 121 corresponds to a first light source and outputs blue light LB in a blue wavelength band within 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 at a predetermined radiation angle around an axis that passes through the center of the light emitting surface of the light source 121 and is parallel to the D1 direction, and is output to the +D1 side. The blue wavelength band is, for example, a wavelength band of 430 nm to 500 nm, and preferably includes 467 nm.

[0011] The light source 121 is composed of, for example, a light emitting diode (LED) that emits blue light LB. The LED that emits blue light LB contains, as a light emitter, a gallium nitride (GaN)-based semiconductor material that has excellent light extraction efficiency. The light source 121 may be composed of one LED or a plurality of LEDs. 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 light source 121 may be configured with a laser diode (LD) containing a GaN-based semiconductor material. When an LED is used for the light source 121, the cost of the light source 121 is reduced and speckle noise of the blue light LB in the image light IM projected onto the screen SCR is reduced. On the other hand, when an LD is used for the light source 121, the blue light LB emitted from the light source 121 can be made higher in output and efficiency.

[0013] The substrate 111 is made of, for example, 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 into the external space.

[0014] 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 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.

[0015] 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, specifically, oblong. The size of the light emitting surface of the light source 121 in the D2 and D3 directions is, for example, 0.25 mm or more and 10 mm or less. The area of ​​the light emitting surface of the light source 121 when viewed along the D1 direction is, for example, 0.25 mm 2 ~10mm x 10mm 2 is.

[0016] The size of incident end 141a in the plane including the D2 and D3 directions may be equal to the size of the light-emitting surface of 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 light source 121 in the plane including the D2 and D3 directions. The dimension along the long side parallel to the D2 direction of opening API 141, through which blue light LB enters at incident end 141a, is 1 mm or more and 3 mm or less, and preferably about 2 mm.

[0017] The exit end 141b corresponds to the first exit end, extends parallel to a plane including the D2 and D3 directions, and is larger than the entrance end 141a. The shape of the exit end 141b when viewed from the D1 direction is the same as the modulation surface of the light modulation element 181 when viewed from the same direction, e.g., rectangular. The size of the exit end 141b in the plane including the D2 and D3 directions is equal to the size of the modulation surface of the light modulation element 181 in the plane including the D2 and D3 directions. The dimension along the long side parallel to the D2 direction of the opening APE141 through which the blue light LB is emitted at the exit end 141b is 14 mm or more and 16 mm or less, preferably about 15 mm. The size of the modulation surface of the light modulation element 181 in the long side direction, i.e., the D2 direction, is, for example, 15 mm. The size of the modulation surface of the light modulation element 181 may be appropriately selected within a range from 6.48 mm×11.52 mm for a 0.52 inch type to 19.44 mm×34.56 mm for a 1.5 inch type.

[0018] The side surface 141s and the reflecting surface 141r connect the periphery of the entrance end 141a to the periphery of the exit end 141b in the direction D1.

[0019] 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, an internal space SP141 surrounded by the incident end 141a, the exit end 141b, and the reflecting surface 141r is a region through which the blue light LB propagates. The size of the internal space SP141 in a plane including the D2 and D3 directions increases as one progresses from the −D1 side to the +D1 side in the D1 direction. The shape of the internal space SP141 in a plane including the D2 and D3 directions changes from the shape of the light-emitting surface of the light source 121 as viewed from the D1 direction to the shape of the modulation surface of the light modulation element 181 as one progresses from the −D1 side to the +D1 side.

[0020] 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 within a plane including the D2 and D3 directions as the light moves 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 through an internal space SP141 surrounded by the incident end 141a, the exit end 141b, and the reflecting surface 141r.

[0021] The modulation surface of the light modulator 181 has a rectangular shape when viewed along the D1 direction, and the light source 121 has a rectangular shape when viewed along the D1 direction. The predetermined angle α, i.e., the taper angle, formed by the side surface 141s and the reflecting surface 141r, including the short side of the rectangular shape parallel to the D3 direction, with respect to the virtual line and the optical axis, is within a range of 7° to 22°. The predetermined angle β, i.e., the taper angle, formed by the side surface 141s and the reflecting surface 141r, including the long side of the rectangular shape parallel to the D2 direction, with respect to the virtual line and the optical axis, is within a range of 14° to 36°. The preferred ranges of the angles α and β are appropriately set by a numerical simulation based on the configuration of the blue light output unit 101 and ray tracing so that the reflective film 251 of the light guide element 141 has a desired spectral reflectance, as will be described later.

[0022] A portion 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, and does not enter the reflecting surface 141r even once, but propagates directly from the incident end 141a to the exit end 141b. The remaining portion 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, and 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 internal space SP141 varies depending on the angle of incidence on the incident end 141a, and follows multiple paths that are reflected by the reflecting surface 141r a different number of times.

[0023] The illuminance distribution of the blue light LB propagating through the internal space SP141 toward the +D1 side is uniform within a plane including the D2 and D3 directions. That is, the light-guiding element 141 uniforms the illuminance distribution of the incident blue light LB within a plane including the D2 and D3 directions. The blue light LB with its uniform illuminance distribution is emitted toward the +D1 side from the emission end 141b.

[0024] The light guide element 141 is, for example, a reflector, and is formed as a hollow member. FIG. 2 is a perspective view of the light guide element 141. As shown in FIG. 2, the light guide element 141 is formed, for example, in a rectangular shape when viewed along the D1 direction, and narrows from the exit end 141b toward the entrance end 141a. 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 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 shape of a different size from the -D1 side end.

[0025] The light-guiding element 141 is composed of, for example, a plate-shaped member 241 and a reflective film 251. The plate-shaped member 241 corresponds to a first substrate. The reflective film 251 corresponds to a first reflective film. As described above, if the shapes of the incident end 141a and the exit end 141b when viewed from the D1 direction are rectangular, the reflector is composed of four trapezoidal plate-shaped members 241A, 241B, 241C, and 241D and the reflective film 251. The edges of the plate-shaped members 241A and 241C corresponding to the upper bases of the trapezoids are parallel to the D2 direction and aligned along the long sides of the incident end 141a. The edges of the plate-shaped members 241A and 241C corresponding to the lower bases of the trapezoids are parallel to the D2 direction and aligned along the long sides of the exit end 141b. The edges corresponding to the upper bases of the trapezoidal shapes of the plate-shaped members 241B and 241D are parallel to the D3 direction and are aligned along the short sides of the incident end 141a. The edges corresponding to the lower bases of the trapezoidal shapes of the plate-shaped members 241B and 241D are parallel to the D3 direction and are aligned along the short sides of the exit end 141b.

[0026] The width, i.e., dimension, of the side parallel to the D2 or D3 direction on the -D1 side corresponding to the upper base of the plate-like members 241A, 241B, 241C, and 241D is set in accordance with the size, in the D2 or D3 direction, of the incident end 141a and the light-emitting surface of the light source 121. The width, i.e., dimension, of the side parallel to the D2 or D3 direction on the +D1 side corresponding to the lower base of the plate-like members 241A, 241B, 241C, and 241D is set in accordance with the size, in the D2 or D3 direction, of the exit end 141b and the modulation surface of the light modulation element 181.

[0027] Considering the size of the light source 121, the width d1 of the edge parallel to the D2 direction on the -D1 side of the plate-shaped members 241A and 241C is 1 mm or more and 3 mm or less, and preferably 2 mm. The width d2 of the edge parallel to the D2 direction on the +D1 side of the plate-shaped members 241A and 241C is 14 mm or more and 16 mm or less, and preferably 15 mm. The length h1 in the D1 direction of the plate-shaped members 241A, 241B, 241C, and 241D from the incident end 141a to the exit end 141b is 5 mm or more and 25 mm or less.

[0028] 3 is a schematic diagram of a substrate having a plate-shaped member 241 and a reflective film 251. The plate-shaped members 241A, 241B, 241C, and 241D are cut into a trapezoidal shape from a base material 248 in which a reflective film 251 is formed on one plate surface of a plate-shaped substrate 245 made of the same material as the plate-shaped member 241. Of the four plate-shaped members 241A, 241B, 241C, and 241D cut out as described above, the side corresponding to one leg of the plate-shaped member 241A is connected to the side corresponding to one leg of the plate-shaped member 241B. The side corresponding to the other leg of the plate-shaped member 241B is connected to the side corresponding to one leg of the plate-shaped member 241C. The side corresponding to the other leg of the plate-shaped member 241C is connected to the side corresponding to one leg of the plate-shaped member 241D. The side portion corresponding to the leg on the other side of the plate-shaped member 241D is connected to the side portion corresponding to the leg on the other side of the plate-shaped member 241A.

[0029] The material of the plate-shaped member 241 and the plate-shaped substrate 245 includes at least one of aluminum (Al) and silver (Ag), which are metals, and glass, ie, silicon dioxide (SiO 2 ), which is a transparent material.

[0030] In the light guide element 141, in order to increase the reflectance of the blue light LB incident from the incident end 141a into the light guide element 141 near the side surface 141s, a reflective film 251 made of a dielectric multilayer film or the like is provided on the plate surface facing the internal space SP141 of each of the plate-like members 241A, 241B, 241C, and 241D constituting the reflector. A part of the blue light LB incident from the incident end 141a into the internal space of the reflector of the light guide element 141 is reflected by the reflective film 251 and travels toward the +D1 side.

[0031] The intensity of the blue light LB reflected by 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 number of low-refractive index layers and high-refractive index layers constituting the dielectric multilayer film, the refractive index of the low-refractive index layers, the refractive index of the high-refractive index layers, and the difference in refractive index between the low-refractive index layers and the high-refractive index layers. When the reflective film 251 is made of a metal 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 density of metal particles.

[0032] The wavelength at which the reflective film 251 has the maximum spectral reflectance in the visible wavelength band is a wavelength in the green wavelength band, preferably a wavelength in the range of 500 nm to 560 nm, and more preferably 555 nm. The wavelength at which the reflective film 251 has the maximum spectral reflectance is the wavelength at which human luminosity is maximized, thereby improving the visibility of images projected by the projector 301. The reflective film 251 has the spectral reflectance in the visible wavelength band of 80% to 100%, preferably 85% to 100%, and more preferably 90% to 100%. The spectral reflectance of the reflective film 251 and the wavelength at which the reflectance is maximized can be effectively controlled by adjusting the parameters of the dielectric multilayer film and metal film that make up the reflective film 251.

[0033] As described above, for example, when angle α is within a range of 7° to 22° and angle β is within a range of 14° to 36°, reflective film 251 is designed so that the angle of incidence of blue light LB, at which the intensity of blue light LB emitted from reflective surface 141r is highest, is within a range of 60° to 90°, and parameters such as the total number of low-refractive-index layers and high-refractive-index layers constituting the dielectric multilayer film and the refractive index difference between the low-refractive-index layers and the high-refractive-index layers are appropriately determined. The relationship between the angle of incidence of blue light LB on reflective surface 141r and reflective film 251 and the intensity of blue light LB emitted from reflective surface 141r and reflective film 251 is obtained by a numerical simulation based on the configuration of blue light emitting unit 101 and ray tracing.

[0034] 1, 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 and at a position overlapping with the light guide element 141 in the D2 and D3 directions. The collimating element 161 collimates the blue light LB emitted from the light guide element 141 along the D1 direction.

[0035] The collimating element 161 is, for example, a plano-convex lens, and has an incident surface formed of a flat surface perpendicular to the D1 direction and an exit surface formed 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, 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-guiding element 141. The incident surface of the plano-convex lens of the collimating element 161 is in contact with the exit end 141b of the light-guiding element 141. Since the collimating element 161 is in contact with the exit end 141b, the blue light LB exited from the exit end 141b of the light-guiding element 141 is taken in by the collimating element 161 to the maximum extent, thereby minimizing loss of the blue light LB. However, the collimating element 161 may be an optical lens other than a plano-convex lens that can collimate the incident blue light LB, and may be disposed at an appropriate distance from the light guide element 141 in the D1 direction.

[0036] The incident-side polarizing element 171 is provided on the optical path of the blue light LB emitted from the collimating element 161, and is disposed on the +D1 side of the collimating element 161 at a position overlapping with the collimating element 161 in the D2 and D3 directions. 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 distance from the light modulation element 181 in the D1 direction. The incident-side polarizing element 171 emits a predetermined polarized light of the blue light LB emitted from the collimating element 161 toward the +D1 side along the D1 direction. The predetermined polarized light is, for example, S-polarized light.

[0037] The incident-side polarizing element 171 is, for example, a reflective polarizing plate or an absorptive polarizing plate having a plate surface parallel to a plane including the D2 and D3 directions. The incident-side polarizing element 171 transmits a portion of the incident blue light LB having a predetermined polarization to the +D1 side, and reflects or absorbs the other portion of the blue light LB to the -D1 side. Note that, if it is desired to suppress return light and stray light to the light source 121, it is desirable that the incident-side polarizing element 171 be an absorptive polarizing plate.

[0038] The blue light LB emitted from the light source 121 includes at least P-polarized light and S-polarized light, and is, for example, randomly polarized. The P-polarized component of the blue light LB emitted from the light source 121 passes sequentially through the light-guiding element 141 and the collimating element 161 as described above, is transmitted through the incident-side polarizing element 171, and is emitted on the +D1 side of the incident-side polarizing element 171. The S-polarized component of the blue light LB, like the P-polarized component, passes sequentially through the light-guiding element 141 and the collimating element 161, but is reflected by the incident surface of the incident-side polarizing element 171 and is emitted on the −D1 side of the incident-side polarizing element 171, or is absorbed by the incident-side polarizing element 171.

[0039] Light modulation element 181 is provided on the optical path of blue light LB emitted from incident-side polarizing element 171, and is disposed on the +D1 side of incident-side polarizing element 171 at a position where it overlaps with incident-side polarizing element 171 in the D2 and D3 directions. Light modulation element 181 corresponds to a first light modulation element, and modulates blue light LB emitted from incident-side polarizing element 171 based on image information transmitted from an image forming device such as a computer (not shown) that is connected to light modulation element 181 from the outside.

[0040] 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 is equipped with a switching element. The switching element is, for example, a polysilicon thin film transistor (TFT). An electrical signal corresponding to the brightness of blue 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 blue light LB incident from the incident-side polarizing element 171 by the operation of the switching element in response to the electrical signal, thereby generating 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 toward the +D1 side along the D1 direction.

[0041] 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 and D3 directions. 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 distance from the light modulation element 181 in the D1 direction. The exit-side polarizing element 175 exits 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 is, for example, P-polarized light.

[0042] 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. The exit-side polarizing element 175 transmits a portion of the incident image light IB containing a predetermined polarization to the +D1 side, and reflects or absorbs another portion of the image light IB to the -D1 side. Note that, 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.

[0043] 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.

[0044] The green light output unit 102 includes a light source 122, a light-guiding element 142, and a collimating element 162. FIG. 4 is a schematic diagram of the green light output unit 102, as viewed along the D3 direction. FIG. 5 is a schematic diagram of the green light output unit 102 and the incident-side polarizing element 172, as viewed along the D3 direction. The light source 122 is supported by a substrate 112. The light source 122 is provided on the +D2 side of the substrate 112, a surface parallel to a plane including the D1 and D3 directions. The light-emitting surface 122a of the light source 122 is disposed substantially parallel to the plane including the D1 and D3 directions, and is located on the opposite side of the light source 122 in the D2 direction from the surface of the light source 122 that contacts the +D2 side of the substrate 112. The light source 122 corresponds to a second light source and emits green light LG in the green wavelength band in the visible wavelength band. The green wavelength band is, for example, a wavelength band from 500 nm to 590 nm, and preferably includes 532 nm.

[0045] The light source 122 is composed of, for example, 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 with a built-in phosphor, and has an LED body 125 made of a semiconductor and a phosphor 124.

[0046] The LED body 125 is provided on the +D2 side surface of the substrate 112. The LED body 125 may be, for example, an LED that emits blue light LB, similar to the light source 121. The LED body 125 includes a GaN-based semiconductor material that has excellent light extraction efficiency.

[0047] The light source 122 may have an LD containing a GaN-based semiconductor material that emits blue light LB as excitation light, instead of the LED body 125. When the light source 122 has the LED body 125, the cost of the light source 122 can be reduced. On the other hand, when the light source 122 is equipped with an LD instead of the LED body 125, the output and efficiency of the excitation light can be increased, and the amount of green light LG emitted from the light source 122 can be increased.

[0048] The phosphor 124 is laminated on an 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. When the LED body 125 emits blue light LB as described above, the phosphor 124 is, for example, cerium-doped yttrium aluminum garnet (YAG:Ce), which is a translucent ceramic. 3+ ) may also be included.

[0049] The light source 122 may be configured with one LED or a plurality of LEDs as a whole, similar to the light source 121. When the light source 122 is configured with 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.

[0050] The substrate 112 is made of, for example, metal, and also functions as a heat dissipation member that receives heat from the light source 122 that emits the green light LG and dissipates the heat to the external space.

[0051] 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 at a position overlapping with the light source 122 in the D1 and D3 directions. 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.

[0052] The incident end 142a corresponds to a second incident end, and extends parallel to a plane including the D1 and D3 directions. 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, specifically, oblong. The size of the light emitting surface 122a of the light source 122 in the D1 and D3 directions is, for example, 0.25 mm or more and 10 mm or less. The area of ​​the light emitting surface of the light source 121 when viewed along the D2 direction is, for example, 0.25 mm 2 ~10mm x 10mm 2 The size of the modulation surface of the light modulation element 182 in the long side direction, i.e., in the D1 direction, is, for example, 15 mm. The size of the modulation surface of the light modulation element 182 is approximately the same as the size of the modulation surface of the light modulation element 181, and may be selected appropriately within a range from, for example, 6.48 mm × 11.52 mm for a 0.52-inch type to 19.44 mm × 34.56 mm for a 1.5-inch type.

[0053] The size of incident end 142a in the plane including the D1 and D3 directions may be equal to the size of light-emitting surface 122a of light source 122 in the plane including the D1 and D3 directions, but is preferably appropriately larger than the size of light-emitting surface 122a in the plane including the D1 and D3 directions. The dimension along the long side parallel to the D1 direction of opening API 142, through which green light LG enters at incident end 142a, is 1 mm or more and 3 mm or less, and preferably about 2 mm.

[0054] The exit end 142b corresponds to a second exit end, extends parallel to a plane including the D1 and D3 directions, and is larger than the entrance end 142a. The shape of the exit end 142b when viewed from the D2 direction is the same as 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 equal to the size of the modulation surface of the light modulation element 182 in the plane including the D1 and D3 directions. The dimension along the long side parallel to the D1 direction of the opening APE142 through which the green light LG is emitted at the exit end 142b is 14 mm or more and 16 mm or less, and preferably about 15 mm.

[0055] The side surface 142s and the reflecting surface 142r connect the periphery of the entrance end 142a and the periphery of the exit end 142b in the direction D2.

[0056] Green light LG emitted from the light source 122 enters the light-guiding element 142 from the incident end 142a. In the light-guiding element 142, an internal space SP142 surrounded by the incident end 142a, the exit end 142b, and the reflecting surface 142r is a region through which the green light LG propagates. The size of the internal space SP142 in a plane including the D1 and D3 directions increases as one progresses from the −D2 side to the +D2 side in the D2 direction. Furthermore, the shape of the internal space SP142 in a plane including the D1 and D3 directions changes from the shape of the light-emitting surface 122a of the light source 122 as viewed from the D2 direction to the shape of the modulation surface of the light modulation element 182 as one progresses from the −D2 side to the +D2 side.

[0057] A side surface 142s of the light-guiding element 142 and a reflecting surface 142r provided on the side surface 142s as described below form a predetermined angle with respect to the optical axis and a virtual line VX perpendicular to the incident end 142a, and move away from the virtual line VX within a plane including the D2 and D3 directions as the light moves from the -D2 side to the +D2 side. The green light LG incident on the light-guiding element 142 propagates through the internal space SP142 from the -D2 side to the +D2 side.

[0058] The modulation surface of the light modulation element 182 has a rectangular shape when viewed along the D2 direction, and the light-emitting surface 122a of the light source 122 has a rectangular shape when viewed along the D2 direction. The predetermined angle α formed by the side surface 142s and the reflecting surface 142r of the rectangular shape, including the short side parallel to the D3 direction, with respect to the virtual line VX and the optical axis, is within a range of 7° to 22°. The predetermined angle β formed by the side surface 141s and the reflecting surface 141r of the rectangular shape, including the long side parallel to the D2 direction, with respect to the virtual line and the optical axis, is within a range of 14° to 36°. The preferred ranges of the angles α and β are appropriately set by a numerical simulation based on the configuration of the green light output unit 102 and ray tracing so that the reflective film 252 of the light guide element 142 has a desired spectral reflectance, as will be described later.

[0059] A ray Lg1, which is a portion of the green light LG incident on the light-guiding element 142, forms an angle with respect to the virtual line VX and the optical axis that is smaller than the angle α or the angle β, and propagates directly from the incident end 142a to the exit end 142b without being incident on the reflecting surface 142r even once. A ray Lg2, which is the remaining portion of the green light LG incident on the light-guiding element 142, forms an angle with respect to the virtual line VX and the optical axis that is equal to or larger than the angle α or the angle β, and propagates from the incident end 142a to the reflecting surface 142r once, is reflected by the reflecting surface 142r, and then reaches the exit end 142b. The remaining rays of the green light LG incident on the light-guiding element 142, other than the ray Lg2, are incident from the incident end 142a to the reflecting surface 142r two or more times, are repeatedly reflected by the reflecting surface 142r, and then reach the exit end 142b.

[0060] The path of the green light LG in the internal space SP142 varies depending on the angle of incidence at the incident end 142a, and extends over multiple paths with different numbers of reflections at the reflecting surface 142r. As a result, the illuminance distribution of the green light LG propagating through the internal space SP142 is homogenized within a plane including the D1 and D3 directions. That is, the light-guiding element 142 homogenizes the illuminance distribution of the incident green light LG within a plane including the D1 and D3 directions. The green light LG with its homogenized illuminance distribution is emitted from the exit end 142b to the +D2 side.

[0061] The light guide element 142 is a hollow reflector made of a plate-like member, similar to the light guide element 141. When viewed along the D2 direction, the end on the -D2 side of the frame of the reflector has the same shape and size as the incident end 142a and the light emitting surface 122a of the light source 122, and is formed, for example, in a rectangular shape. The end on 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 shape with a different size from the end on the -D2 side.

[0062] The light guide element 142 is composed of a plate-shaped member 242 and a reflective film 252. The plate-shaped member 242 corresponds to a second base material. The light guide element 142 is composed of four trapezoidal plate-shaped members 242, each with its legs connected to one another. The width, i.e., dimensions, of the sides parallel to the D1 or D3 direction on the -D2 side, which corresponds to the upper base of each of the four plate-shaped members 242, are set according to the size of the incident end 142a and the light-emitting surface 122a in the D1 or D3 direction. The width, i.e., dimensions, of the sides parallel to the D1 or D3 direction on the +D2 side, which corresponds to the lower base of each of the four plate-shaped members 242, are set according to the size of the exit end 142b and the modulation surface of the light modulation element 182 in the D1 or D3 direction.

[0063] Considering the size of the light source 122, the width, i.e., dimension, of the edge parallel to the D1 direction on the -D2 side of two opposing plate-like members 242A, 242C in a plane including the D1 and D3 directions is 1 mm or more and 3 mm or less, preferably 2 mm. The width, i.e., dimension, of the edge parallel to the D1 direction on the +D2 side of two opposing plate-like members 242A, 242C is 14 mm or more and 16 mm or less, preferably 15 mm. The length in the D2 direction of each of the plate-like members 242A, 242B, 242C, and 242D from the incident end 142a to the exit end 142b is 5 mm or more and 25 mm or less. The shape of the light guide element 142 is the same as that of the light guide element 141.

[0064] The material of the plate-shaped member 242 contains at least one of Al, Ag, and glass, ie, SiO 2 , and is preferably the same as the material of the plate-shaped member 241 .

[0065] The four plate-shaped members 242 are cut into trapezoidal shapes from a base material in which a reflective film 252 is formed on one plate surface of a plate-shaped substrate made of the same material as the plate-shaped member 242. As described above, if the material of the plate-shaped member 242 is the same as the material of the plate-shaped member 241 and the configuration of the reflective film 252 is the same as the configuration of the reflective film 251, the plate-shaped member 242 is cut out from the same base material 248 as the plate-shaped member 241. As described above, of the four plate-shaped members 242 cut out, a side portion corresponding to one leg of a first plate-shaped member 242 is connected to a side portion corresponding to one leg of a second plate-shaped member 242. A side portion corresponding to the other leg of the second plate-shaped member 242 is connected to a side portion corresponding to one leg of a third plate-shaped member 242. A side portion corresponding to the other leg of the third plate-shaped member 242 is connected to a side portion corresponding to one leg of a fourth plate-shaped member 242. The side portion of the fourth plate-shaped member 242 corresponding to the leg on the other side is connected to the side portion of the first plate-shaped member 242 corresponding to the leg on the other side.

[0066] 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 into the light-guiding element 142 near the side surface 142s, a reflective film 252 such as a dielectric multilayer film is provided on the plate surface of the plate-like member constituting the reflector opposite to the side surface 142s, i.e., the plate surface facing the internal space SP142. Some rays of the green light LG, including the light ray Lg2 incident from the incident end 142a into the internal space SP142 of the light-guiding element 142, are reflected by the reflective film 252 and travel toward the +D2 side.

[0067] The intensity of the green light LG reflected by 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 number of low-refractive index layers and high-refractive index layers constituting the dielectric multilayer film, the refractive index of the low-refractive index layers, the refractive index of the high-refractive index layers, and the difference in refractive index between the low-refractive index layers and the high-refractive index layers. When the reflective film 252 is made of a metal 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 density of metal particles.

[0068] The reflective film 252 of the light guide element 142 has the same spectral reflectance as the reflective film 251 of the light guide element 141. Specifically, the wavelength at which the reflective film 252 has the maximum reflectance in the visible wavelength band is a wavelength in the green wavelength band, similar to the reflective film 251, preferably a wavelength in the range of 500 nm to 560 nm, and more preferably 555 nm. The spectral reflectance of the reflective film 252 in the visible wavelength band is 80% to 100%, preferably 85% to 100%, and more preferably 90% to 100%.

[0069] During the manufacturing process of the reflective films 251 and 252, manufacturing errors may occur in the parameters of the dielectric multilayer film. For example, if there is an error in the thickness of each layer of the low-refractive-index layers and high-refractive-index layers of the dielectric multilayer film constituting the reflective films 251 and 252 on the surface to be formed, the spectral reflectance of the manufactured dielectric multilayer film may have a distribution similar to the expected spectral reflectance, but may deviate by several nanometers from the expected overall spectral reflectance distribution. Furthermore, even if the thicknesses of the low-refractive-index layers and high-refractive-index layers of the dielectric multilayer film constituting the reflective films 251 and 252 are accurate and uniform, the spectral reflectance of the manufactured dielectric multilayer film may deviate by several percent from the expected spectral reflectance due to the presence or amount of impurities, etc. Even if manufacturing errors occur in the dielectric multilayer film of the reflective films 251 and 252, the wavelength difference between the wavelength at which the spectral reflectance of the reflective film 251 is maximized and the wavelength at which the spectral reflectance of the reflective film 252 is maximized is at least 5 nm or less, preferably 3 nm or less. The difference between the maximum spectral reflectance of reflective film 251 and the maximum spectral reflectance of reflective film 252 is at least 3%. Within this range, the spectral reflectance of reflective film 252 can be said to be the same as the spectral reflectance of reflective film 251.

[0070] The wavelength at which the spectral reflectance of the reflective film 252 is maximized is also the wavelength at which human visual sensitivity is maximized, thereby improving the visibility of the image projected by the projector 301. By adjusting the parameters of the dielectric multilayer film and metal film that make up the reflective film 252, the spectral reflectance of the reflective film 252 and the wavelength at which the reflectance is maximized can be effectively controlled.

[0071] As described above, for example, when angle α is within the range of 7° to 22° and angle β is within the range of 14° to 36°, reflective film 252 is designed and parameters of the dielectric multilayer film are appropriately determined so that the angle of incidence of green light LG at which the intensity of green light LG emitted from reflective surface 142r and reflective film 252 is highest is within the range of 60° to 90°. The relationship between the angle of incidence of green light LG on reflective film 252 and the intensity of green light LG emitted from reflective film 252 is also obtained by a numerical simulation based on the configuration of green light emitting unit 102 and ray tracing.

[0072] The collimating 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 collimating element 162 collimates the green light LG emitted from the light guide element 142 along the D2 direction.

[0073] The collimating element 162 is, for example, a plano-convex lens, and has an incident surface 162a consisting of a flat surface perpendicular to the D2 direction, and an exit surface 162b consisting 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 162 is at least on the -D2 side of the collimating element 162, 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 having the collimating element 162 in contact with the exit end 142b, the green light LG exiting from the exit end 142b of the light-guiding element 142 is taken in by the collimating element 162 to the maximum extent, thereby minimizing loss of the green light LG. However, the collimating element 162 may be an optical lens other than a plano-convex lens that can collimate the incident green light LG, and may be disposed at an appropriate distance from the light-guiding element 142 in the D2 direction.

[0074] 5, a light ray Lg1, which is a part of the green light LG incident on the light-guiding element 142, propagates directly from the incident end 142a to the exit end 142b without ever hitting the reflecting surface 142r. A light ray Lg2, which is the remaining part of the green light LG incident on the light-guiding element 142, propagates from the incident end 142a to the reflecting surface 142r once, is reflected by the reflecting surface 142r, and then reaches the exit end 142b. As described above, there are many other paths of the green light LG propagating inside the light-guiding element 142 in addition to the paths of the light rays Lg1 and Lg2.

[0075] 1 and 5, 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 with an appropriate gap between it and the light modulation element 182 in the D2 direction.

[0076] The incident-side polarizing element 172 emits a predetermined polarized light of the green light LG emitted from the parallelizing element 162 toward the +D2 side along the D2 direction. The predetermined polarized light is, for example, S-polarized light. The incident-side polarizing element 172 is, for example, a reflective polarizing plate or an absorptive polarizing plate having a plate surface parallel to a plane including the D1 and D3 directions. The incident-side polarizing element 172 transmits a portion of the incident green light LG that includes the predetermined polarized light toward the +D2 side, and reflects or absorbs the other portion of the green light LG toward the -D2 side.

[0077] Incidentally, if it is desired to suppress stray light and return light to light source 122, it is desirable that incident-side polarizing element 172 be an absorptive polarizing plate. However, if light source 122 has phosphor 124, as in green light emitting unit 102, incident-side polarizing element 172 may be a reflective polarizing plate because light reflected from the reflective polarizing plate can be utilized to excite phosphor 124.

[0078] As shown in FIG. 5, 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 the S-polarized component of the green light LG emitted from the light source 122, and the green light LGP, which is the P-polarized component of the green light LG, pass through the light-guiding element 142, where the illuminance distribution is homogenized by the light-guiding element 142 in a plane including the D1 direction and the D3 direction, and the green light LGS and LGP are emitted toward the +D2 side of the light-guiding element 142. The green light LGS and LGP pass through the collimating element 162 and are collimated by the collimating element 162. The collimated green light 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 toward the +D2 side of the incident-side polarizing element 172. The green light LGP is reflected by the incident surface 172 a of the incident-side polarizing element 172 and is emitted to the −D 2 side of the incident-side polarizing element 172 , or is absorbed by the incident-side polarizing element 172 .

[0079] The green light LGP reflected from the incident-side polarizing element 172 toward the -D2 side passes sequentially through the collimating element 162 and the light-guiding element 142, travels along the D2 direction toward the -D2 side, is collected within a plane including the D1 and D3 directions, 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 toward the -D2 side, and emits green light LG containing the green light LGS and LGP again toward the +D2 side from the emission surface 124a. Because the incident-side polarizing element 172 is configured as 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.

[0080] 1, light modulation element 182 is provided on the optical path of green light LG emitted from incident-side polarizing element 172, and is disposed on the +D2 side of incident-side polarizing element 172 at a position where it overlaps with incident-side polarizing element 172 in the D1 and D3 directions. Light modulation element 182 corresponds to a second light modulation element, and modulates green light LG emitted from incident-side polarizing element 172 based on image information transmitted from an external image forming device such as a computer (not shown) connected to light modulation element 182.

[0081] 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 equipped with a switching element. The switching element is, for example, a TFT. An electrical signal corresponding to the brightness of 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 green light LG incident from the incident-side polarizing element 172 by operation of the switching element in response to the electrical signal, thereby generating 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 toward the +D2 side along the D2 direction.

[0082] 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 with an appropriate gap between it and the light modulation element 182 in the D2 direction. The exit-side polarizing element 176 exits predetermined polarized light of the image light IG exiting from the light modulation element 182 toward the +D2 side along the D2 direction. The predetermined polarized light is, for example, P-polarized light.

[0083] 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 or absorbs the other portion of the image light IG to the -D2 side. Note that, if it is desired to suppress return light and stray light to the light modulation element 182, it is desirable to employ an absorptive polarizing plate as the exit-side polarizing element 176.

[0084] 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.

[0085] The red light output 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 113. The light source 123 is provided on a surface of the substrate 113 on the -D1 side of a surface parallel to a plane including the D2 and D3 directions. The light emitting surface of the light source 123 is disposed substantially parallel to the plane including the D2 and D3 directions, and is the surface of the light source 123 on the opposite side in the D1 direction from the surface of the light source 123 that is in contact with the surface of the substrate 113 on the +D2 side. The light source 123 corresponds to a third light source and outputs red light LR in a red wavelength band within the visible wavelength band. The red wavelength band is, for example, a wavelength band of 590 nm to 700 nm, and preferably includes 630 nm.

[0086] The light source 123 is composed of, for example, an LED that emits red light LR. The LED that emits red light LR contains aluminum gallium indium phosphide (AlGaInP) as a light emitter, which has excellent light extraction efficiency. The light source 123 may be composed of one LED or 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.

[0087] The light source 123 may be configured with an LD containing AlGaInP. When an LED is used for the light source 123, the cost of the light source 123 is reduced and speckle noise of the red light LR in the image light IM projected onto the screen SCR is reduced. On the other hand, when an LD is used for the light source 123, the red light LR emitted from the light source 123 can be made higher in output and efficiency.

[0088] The substrate 113 is made of, for example, 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 into the external space.

[0089] 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 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.

[0090] 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, specifically, oblong. The size of the light emitting surface of the light source 123 in the D2 and D3 directions is, for example, 0.25 mm or more and 10 mm or less. The area of ​​the light emitting surface of the light source 123 when viewed along the D1 direction is, for example, 0.25 mm 2 ~10mm x 10mm 2 is.

[0091] The size of incident end 143a in the plane including the D2 and D3 directions may be equal to the size of the light-emitting surface of light source 123 in the plane including the D2 and D3 directions, but is preferably appropriately larger than the size of the light-emitting surface of light source 123 in the plane including the D2 and D3 directions. The dimension along the long side parallel to the D2 direction of the opening into which red light LR is incident at incident end 143a is 1 mm or more and 3 mm or less, and preferably about 2 mm.

[0092] The exit end 143b corresponds to the third exit end, extends parallel to a plane including the D2 and D3 directions, and is larger than the entrance 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, e.g., rectangular. The size of the exit end 143b in the plane including the D2 and D3 directions is equivalent to the size of the modulation surface of the light modulation element 183 in the plane including the D2 and D3 directions. The dimension along the long side parallel to the D2 direction of the opening through which the red light LR is emitted at the exit end 143b is 14 mm or more and 16 mm or less, preferably approximately 15 mm. The size of the modulation surface of the light modulation element 183 in the long side direction, i.e., the D2 direction, is, for example, 15 mm. The size of the modulation surface of the light modulation element 183 may be appropriately selected within a range from 6.48 mm×11.52 mm for a 0.52 inch type to 19.44 mm×34.56 mm for a 1.5 inch type.

[0093] The side surface 143s and the reflecting surface 143r connect the periphery of the entrance end 143a to the periphery of the exit end 143b in the direction D1.

[0094] Red light LR emitted from the light source 123 enters the light-guiding element 143 from the incident end 143a. In the light-guiding element 143, the internal space surrounded by the incident end 143a, the exit end 143b, and the reflecting surface 143r is the region through which the red light LR propagates. The size of the internal space surrounded by the incident end 143a, the exit end 143b, and the reflecting surface 143r in a plane including the D2 and D3 directions increases as the distance from the +D1 side to the -D1 side in the D1 direction increases. Furthermore, the shape of the internal space surrounded by the incident end 143a, the exit end 143b, and the reflecting surface 143r in a plane including the D2 and D3 directions changes from the shape of the light-emitting surface of the light source 123 as viewed from the D1 direction to the shape of the modulation surface of the light modulation element 183 as the distance from the +D1 side to the -D1 side increases.

[0095] A side surface 143s of the light-guiding 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 perpendicular to the incident end 143a and the optical axis, and move away from the virtual line within 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-guiding element 142 propagates from the -D2 side to the +D2 side through an internal space surrounded by the incident end 143a, the exit end 143b, and the reflecting surface 143r.

[0096] The shape of the modulation surface of the light modulator 183 when viewed along the D1 direction is rectangular, and the shape of the light source 123 when viewed along the D1 direction is rectangular. The predetermined angle α formed by the side surface 143s and the reflecting surface 143r of the rectangular shape, including the short side parallel to the D3 direction, with respect to the virtual line and the optical axis, is preferably within a range of 7° to 22°. The predetermined angle β formed by the side surface 143s and the reflecting surface 143r of the rectangular shape, including the long side parallel to the D2 direction, with respect to the virtual line and the optical axis, is preferably within a range of 14° to 36°. The preferable ranges of the angles α and β are appropriately set by a numerical simulation based on the configuration of the red light output unit 103 and ray tracing so that the reflective film 253 of the light guide element 143 has a desired spectral reflectance, as will be described later.

[0097] A portion of the red light LR incident on the light-guiding element 143 forms an angle with respect to the virtual axis and the optical axis that is smaller than a predetermined angle, and propagates directly from the incident end 143a to the exit end 143b without being incident on the reflecting surface 143r even once. The remaining portion of the red light LR incident on the light-guiding element 143 forms an angle with respect to the virtual axis and the optical axis that is equal to or larger than a predetermined angle, and is incident on the reflecting surface 143r from the incident end 143a one or more times, and reaches the exit end 143b after being reflected by the reflecting surface 143r. The path of the red light LR in the internal space 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 follows multiple paths that are reflected by the reflecting surface 143r a different number of times.

[0098] The illuminance distribution of the red light LR propagating through the internal space 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-guiding 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 its uniform illuminance distribution is emitted from the exit end 143b to the -D1 side.

[0099] The light guide element 143 is a reflector, similar to the light guide elements 141 and 142, and is formed as a hollow member. When viewed along the D1 direction, the end on the +D1 side of the light guide element 143 has the same shape and size as the incident end 143a and the light emitting surface of the light source 123, and is formed, for example, in a rectangular shape. The end on the -D1 side of the light guide element 143 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 shape with a different size from the end on the +D1 side.

[0100] The reflector of the light guide element 143 is composed of four plate-like members 243 and a reflective film 253. The four plate-like members 243 correspond to a third base material. The reflector is composed of four trapezoidal plate-like members 243, each with its legs connected to one another. The width, i.e., dimensions, of the sides parallel to the D2 or D3 direction on the +D1 side, which corresponds to the upper base of each of the four plate-like members 243, are set according to the incident end 143a and the size of the light-emitting surface of the light source 123 in the D2 or D3 direction. The width, i.e., dimensions, of the sides parallel to the D2 or D3 direction on the -D1 side, which corresponds to the lower base of each of the four plate-like members 243, are set according to the exit end 143b and the size of the modulation surface of the light modulation element 183 in the D2 or D3 direction.

[0101] Considering the size of the light source 123, the width, i.e., dimension, of the edge of the plate-shaped member 243 on the +D1 side parallel to the D2 direction is 1 mm or more and 3 mm or less, and preferably 2 mm. The width, i.e., dimension, of the edge of the plate-shaped member 243 on the -D1 side parallel to the D2 direction is 14 mm or more and 16 mm or less, and preferably 15 mm. The length of the plate-shaped member 243 in the D1 direction from the incident end 143a to the exit end 143b is 5 mm or more and 25 mm or less. The shape of the light-guiding element 143 is the same as the shapes of the light-guiding elements 141 and 142.

[0102] The material of the plate-shaped member 243 contains at least one of Al, Ag, and glass, ie, SiO 2 , and is preferably the same as the material of the plate-shaped members 241 and 242 .

[0103] The four plate-shaped members 243 are cut into trapezoidal shapes from a base material in which a reflective film 253 is formed on one plate surface of a plate-shaped substrate made of the same material as the plate-shaped member 243. As described above, if the material of the plate-shaped member 243 is the same as the material of the plate-shaped member 241 and the configuration of the reflective film 253 is the same as the configuration of the reflective film 251, the plate-shaped member 243 is cut out from the same base material 248 as the plate-shaped member 241. As described above, of the four plate-shaped members 243 cut out, a side portion corresponding to one leg of a first plate-shaped member 243 is connected to a side portion corresponding to one leg of a second plate-shaped member 243. A side portion corresponding to the other leg of the second plate-shaped member 243 is connected to a side portion corresponding to one leg of a third plate-shaped member 243. A side portion corresponding to the other leg of the third plate-shaped member 243 is connected to a side portion corresponding to one leg of a fourth plate-shaped member 243. The side portion of the fourth plate-shaped member 243 corresponding to the leg on the other side is connected to the side portion of the first plate-shaped member 243 corresponding to the leg on the other side.

[0104] 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 the plate surface opposite the side surface 143s of the plate-like member constituting the reflector, i.e., the plate surface facing the internal space of the reflector. 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.

[0105] The intensity of the red light LR reflected by the reflective film 253 and emitted from 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 number of low-refractive-index layers and high-refractive-index layers constituting the dielectric multilayer film, the refractive index of the low-refractive-index layers, the refractive index of the high-refractive-index layers, and the difference in refractive index between the low-refractive-index layers and the high-refractive-index layers. When the reflective film 253 is made of a metal 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 density of metal particles.

[0106] The reflective film 253 of the light guide element 143 has the same spectral reflectance as the reflective film 251 of the light guide element 141 and the reflective film 252 of the light guide element 142. Specifically, the wavelength at which the reflective film 253 has the maximum reflectance in the visible wavelength band is a wavelength in the green wavelength band, preferably a wavelength in the range of 500 nm to 560 nm, and more preferably 555 nm, similar to the reflective films 251 and 252. The spectral reflectance of the reflective film 253 in the visible wavelength band is 80% to 100%, preferably 85% to 100%, and more preferably 90% to 100%.

[0107] During the manufacturing process of the reflective film 253, manufacturing errors may occur in the parameters of the dielectric multilayer film. For example, if there is an error in the thickness of each layer of the low-refractive index layers and high-refractive index layers of the dielectric multilayer film constituting the reflective film 253 on the surface to be formed, the spectral reflectance of the manufactured dielectric multilayer film may have a distribution similar to the expected spectral reflectance, but may deviate by several nanometers from the expected overall spectral reflectance distribution. Furthermore, even if the thicknesses of the low-refractive index layers and high-refractive index layers of the dielectric multilayer film constituting the reflective film 253 are accurate and uniform, the spectral reflectance of the manufactured dielectric multilayer film may deviate by several percent from the expected spectral reflectance due to the presence or amount of impurities, etc. Even if manufacturing errors occur in the dielectric multilayer film of the reflective film 253, the wavelength difference between the wavelength at which the spectral reflectance of the reflective film 253 is maximized and the wavelength at which the spectral reflectance of the reflective films 251 and 252 is maximized is at least 5 nm or less, preferably 3 nm or less. The difference between the maximum spectral reflectance of the reflective film 253 and the maximum spectral reflectance of the reflective films 251 and 252 is at least 3%. Within this range, the spectral reflectance of the reflective film 253 can be said to be the same as the spectral reflectance of the reflective films 251 and 252.

[0108] The wavelength at which the spectral reflectance of the reflective film 253 is maximized is also the wavelength at which human visual sensitivity is maximized, thereby improving the visibility of the image projected by the projector 301. By adjusting the parameters of the dielectric multilayer film and metal film that make up the reflective film 253, the spectral reflectance of the reflective film 253 and the wavelength at which the reflectance is maximized can be effectively controlled.

[0109] As described above, for example, when the angle α is within a range of 7° to 22° and the angle β is within a range of 14° to 36°, the reflective film 253 is designed, and the parameters of the dielectric multilayer film are appropriately determined, so that the angle of incidence of the red light LR at which the intensity of the red light LR emitted from the reflective surface 143r and the reflective film 253 is highest is within a range of 60° to 90°. The relationship between the angle of incidence of the red light LR on 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.

[0110] 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 and D3 directions. The collimating element 163 collimates the red light LR emitted from the light guide element 143 along the D1 direction.

[0111] The collimating element 163 is, for example, a plano-convex lens, and has an incident surface formed of a flat surface perpendicular to the D1 direction and an exit surface formed 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, 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 incident surface of the collimating element 163 is in contact with the exit end 143b of the light-guiding element 143. By having the collimating element 163 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 by the collimating element 163 to the maximum extent, thereby suppressing loss of the red light LR. However, the parallelizing element 163 may be an optical lens other than a plano-convex lens that can parallelize the incident red light LR, and may be disposed at an appropriate distance from the light-guiding element 143 in the D1 direction.

[0112] 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.

[0113] The incident-side polarizing element 173 emits a predetermined polarized light of the red light LR emitted from the parallelizing element 163 toward the -D1 side along the D1 direction. The predetermined polarized light is, for example, S-polarized light. The incident-side polarizing element 173 is, for example, a reflective polarizing plate or an absorptive polarizing plate having a plate surface parallel to a plane including the D2 and D3 directions. The incident-side polarizing element 173 transmits a portion of the incident red light LR that contains the predetermined polarized light toward the -D1 side, and reflects or absorbs the other portion of the red light LR toward the +D1 side. Note that, if it is desired to suppress return light and stray light to the light source 123, it is desirable that the incident-side polarizing element 173 be an absorptive polarizing plate.

[0114] 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 sequentially through the light-guiding element 143 and the collimating element 163 as described above, is transmitted through the incident-side polarizing element 173, and is emitted on 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 sequentially through the light-guiding element 143 and the collimating element 163, but is reflected by the incident surface of the incident-side polarizing element 173 and is emitted on the +D1 side of the incident-side polarizing element 173, or is absorbed by the incident-side polarizing element 173.

[0115] 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 where it overlaps 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.

[0116] 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 is equipped with a switching element. The switching element is, for example, a 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 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 in response to the electrical signal, thereby generating 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 toward the -D1 side along the D1 direction.

[0117] 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 distance from the light modulation element 183 in the D1 direction. The exit-side polarizing element 177 exits 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 is, for example, P-polarized light.

[0118] 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 containing a predetermined polarization to the +D2 side, and reflects or absorbs the other portion of the green light LG to the -D2 side. Note that, if it is desired to suppress return light and stray light to the light modulation element 183, it is desirable that the exit-side polarizing element 177 be an absorptive polarizing plate.

[0119] Light combining element 200 is disposed in a region where the optical path of red image light IR emitted from emission-side polarizing element 175, the optical path of green image light IG emitted from emission-side polarizing element 176, and the optical path of red image light IR emitted from emission-side polarizing element 177 intersect. Light combining element 200 combines image light IB, IG, and IR emitted from emission-side polarizing elements 175, 176, and 177, and emits the combined light to the +D2 side along the D2 direction.

[0120] 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 and D3 directions and overlap each other in the D2 and D3 directions. The incident surface 210d and the exit surface 210b are parallel to a plane including the D1 and D3 directions and overlap each other in the D1 and D3 directions.

[0121] The reflective film 211 is arranged such that, when viewed along the D3 direction, the reflective film 211 changes from +D2 side to -D2 side as it moves from -D1 side to +D1 side. The reflective film 212 is arranged such that, when viewed along the D3 direction, the reflective film 212 changes 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 exit surface 210b and the incident surface 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.

[0122] When viewed from the D3 direction, the cross dichroic prism 210 is configured by four right-angle prisms bonded together at their right-angle surfaces, with their right-angle vertices aligned at the center of the light combining element 200. The four right-angle prisms of the cross dichroic prism 210 are formed of a transparent material that transmits light in the visible wavelength range. The reflective film 211 is disposed on one of the right-angle surfaces of the four right-angle prisms, which moves from the +D2 side to the -D2 side as one moves from the -D1 side to the +D1 side, as described above, and is formed of, for example, a dielectric multilayer film. The reflective film 212 is disposed on one of the right-angle surfaces of the four right-angle prisms, which moves from the -D2 side to the +D2 side as one moves from the -D1 side to the +D1 side, as described above.

[0123] The P-polarized light of 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 along the D1 direction toward the +D1 side, passes through the reflective film 211, is reflected by the reflective film 212, and travels toward the +D2 side. The P-polarized light of 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 along the D2 direction toward the +D2 side, passes through the reflective films 211 and 212, and travels straight toward the +D2 side. The P-polarized light of 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 along the D1 direction toward the −D1 side, passes through the reflective film 212, is reflected by the reflective film 211, and travels 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 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.

[0124] 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 SCR 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 SCR.

[0125] The projection optical system 250 is configured, for example, by 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 aspherical lens, a free-form lens, and the like.

[0126] 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 guide element (first light guide element) 141, a light guide element (second light guide element) 142, a light modulation element (first light modulation element) 181, a light modulation element (second light modulation element) 182, 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 guide element 141 has an incident end (first incident 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. The light guide element 141 uniforms the illuminance of the blue light LB in a plane including the D2 and D3 directions. The light guide element 142 has an incident end (second incident 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. The light guide element 142 uniforms the illuminance of the green light LG in a plane including the D1 and D3 directions. The light modulation element 181 modulates the blue light LB emitted from the light guide element 141 based on image information. The light modulation element 182 modulates the green light LG emitted from the light guide element 142 based on image information. The light combining element 200 combines the image light (first light) IB emitted from the light modulation element 181 and the image light (second light) IG emitted from the light modulation element 182, and emits the combined light. 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 spectral reflectance of the light guide element 142 is the same as the spectral reflectance of the light guide element 141.

[0127] In the projector 301 of this embodiment, two colored lights emitted from the light sources 121 and 122, i.e., blue light LB and green light LG, are directly converted into image lights IB and IG by the light modulation elements 181 and 182, and the image lights IB and IG are combined by the light combining element 200 and projected onto the screen SCR. In conventional projectors, white light is generated and separated into colored lights, such as blue light and green light, by a color separation element or a color separation optical system. Each colored light is converted into image light by a light modulation element, and the image light is combined by the light combining element and projected. In contrast, the projector 301 of this embodiment does not require a color combining element or a color combining optical system that combines the colored lights, or a color separation element or a color separation optical system that separates the colored lights, before the light modulation elements corresponding to each colored light. Therefore, the projector 301 of this embodiment can reduce the number of parts and devices, and can be smaller in size, compared to conventional projectors. The projector 301 of this embodiment can be made more compact than conventional projectors.

[0128] The spectral reflectance of the light-guiding element 141 includes both a spectral reflectance that is substantially independent of the spectral reflectance of the plate-shaped member 241 and is attributable solely to the spectral reflectance of the reflective film 251, as in the embodiment of the present invention, and a spectral reflectance that is attributable to the spectral reflectance of the plate-shaped member 241 and the spectral reflectance of the reflective film 251, as a result of adjusting the transmittance of blue light LB, etc., in the reflective film 251. In the latter case where the transmittance of blue light LB, etc., in the reflective film 251 is adjusted, for example, parameters of the dielectric multilayer film that constitutes the reflective film 251 are adjusted, and the spectral reflectance of the plate-shaped member 241 is corrected by the spectral reflectance of the reflective film 251 depending on the adjustment amount of the parameters. Similarly, the spectral reflectance of the light-guiding element 142 includes both a spectral reflectance that is substantially independent of the spectral reflectance of the plate-shaped member 242 and is attributable solely to the spectral reflectance of the reflective film 252, as in the embodiment of the present invention, and a spectral reflectance that is attributable to the spectral reflectance of the plate-shaped member 242 and the spectral reflectance of the reflective film 252, as a result of adjusting the transmittance of green light LG, etc., in the reflective film 252. The spectral reflectance of light-guiding element 142 being the same as the spectral reflectance of light-guiding element 141 means that, even taking into account manufacturing errors of reflective films 251 and 252, the wavelength difference between the wavelength at which the spectral reflectance of light-guiding element 141 is maximized and the wavelength at which the spectral reflectance of light-guiding element 142 is maximized is 5 nm or less, and the difference between the maximum reflectance of the spectral reflectance of light-guiding element 141 and the maximum reflectance of the spectral reflectance of light-guiding element 142 is 3% or less.

[0129] In the projector 301 of this embodiment, if the spectral reflectance of the reflective film 251 of the light guide element 141 and the spectral reflectance of the reflective film 252 of the light guide element 142 are the same, a common reflective film can be disposed on the plate surface of the plate-shaped member 241 of the light guide element 141 that faces the internal space SP141 and the plate surface of the plate-shaped member 242 of the light guide element 142 that faces the internal space SP142. According to the projector 301 of this embodiment, it is possible to reduce the time, effort, and cost required to manufacture the reflective films 251 and 252, while optimizing the efficiency of use of the blue light LB and green light LG emitted from the light guide elements 141 and 142, the illuminance ratio on the screen SCR, and other optical characteristics.

[0130] The projector 301 of this embodiment further includes a light source (third light source) 123, a light guide element (third light guide element) 143, and a light modulation element (first light modulation element) 181. 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 143 has an incident end (third incident 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. The light guide element 143 homogenizes the illuminance of the red light LR in a plane including the D1 and D3 directions. The light modulation element 183 modulates the red light LR emitted from the light guide element 143 based on image information. The light combining element 200 further combines the image lights IB and IG with image light (third light) IR emitted from the light modulation element 183 and emits the combined light. In the projector 301 of this embodiment, the spectral reflectance of the light guide element 143 is the same as the spectral reflectance of the light guide element 141 and the spectral reflectance of the light guide element 142.

[0131] In the projector 301 of this embodiment, blue light LB, green light LG, and red light LR emitted from the light sources 121, 122, and 123 are directly converted into image light IB, IG, and IR by the light modulation elements 181, 182, and 183, and the image light IB, IG, and IR are combined by the light combining element 200 to project three-color image light IM. The projector 301 of this embodiment does not require a color combining element or color combining optical system that combines the respective color lights, or a color separating element or color separating optical system that separates the respective color lights, in a stage preceding the light modulation elements corresponding to the three color lights. Therefore, the projector 301 of this embodiment can further reduce the number of parts and devices, and the size, compared to conventional projectors. The three-plate projector 301 of this embodiment can be made smaller than conventional projectors.

[0132] The spectral reflectance of the light guide element 143 includes both a spectral reflectance that is substantially independent of the spectral reflectance of the plate-shaped member 243 and is attributable solely to the spectral reflectance of the reflective film 253, as in the embodiment, and a spectral reflectance that is attributable to the spectral reflectance of the plate-shaped member 243 and the spectral reflectance of the reflective film 253, with the transmittance of red light LR, etc., adjusted in the reflective film 253. The phrase "the spectral reflectance of the light guide element 143 is the same as the spectral reflectance of the light guide elements 141 and 142" means that, even taking into account manufacturing errors of the reflective film 253, the wavelength difference between the wavelength at which the reflectance of the light guide element 143 is maximized and the wavelength at which the reflectance of the light guide elements 141 and 142 is maximized is 5 nm or less, and the difference between the maximum reflectance of the light guide element 143 and the maximum reflectance of the light guide elements 141 and 142 is 3% or less.

[0133] In the projector 301 of this embodiment, if the spectral reflectance of the reflective film 253 of the light guide element 143 is the same as the spectral reflectance of the reflective films 251 and 252, a reflective film common to the plate surface of the plate member 243 of the light guide element 143 facing the internal space, the plate surface of the plate member 241 of the light guide element 141 facing the internal space SP141, and the plate surface of the plate member 242 of the light guide element 142 facing the internal space SP142, can be disposed. According to the projector 301 of this embodiment, it is possible to further reduce the manufacturing time, effort, and manufacturing cost of the reflective films 251, 252, and 253 while optimizing the optical characteristics such as the utilization efficiency of the blue light LB, green light LG, and red light LR emitted from the light guide elements 141, 142, and 143, and the illuminance ratio on the screen SCR.

[0134] In the projector 301 of this embodiment, the first light is blue light LB. The second light is green light LG. The third light is red light LR. The projector 301 of this embodiment can generate and project image light IM with high color reproducibility.

[0135] In the projector 301 of this embodiment, the first wavelength band includes 467 nm. The second wavelength band includes 532 nm. The third wavelength band includes 630 nm. In the projector 301 of this embodiment, the first wavelength band, the second wavelength band, and the third wavelength band include the primary color wavelengths of ITU-R Recommendation BT.2020 or Rec.2020, which are representative color standards. The projector 301 of this embodiment excels in color reproduction and compliance with color standards.

[0136] In the projector 301 of this embodiment, the wavelength (wavelength band) at which the reflectance is maximum in the spectral reflectance of the light guide elements 141, 142, and 143 includes 555 nm.

[0137] In the projector 301 of this embodiment, the wavelength at which the spectral reflectance of the light-guiding elements 141, 142, and 143 and the spectral reflectance of the reflective films 251, 252, and 253 are maximum coincides with the wavelength at which human visual sensitivity is maximum, thereby improving the visibility of the projected image.

[0138] In the projector 301 of this embodiment, the light guide element 141 includes a plurality of plate-shaped members (first base materials) 241 each having a reflective film (first reflective film) 251 that reflects blue light LB, and is configured with, for example, four plate-shaped members 241A, 241B, 241C, and 241D. The light guide element 142 includes a plurality of plate-shaped members (second base materials) 242 each having a reflective film (second reflective film) 252 that reflects green light LG, and is configured with, for example, four plate-shaped members 242. The light guide element 143 includes a plurality of plate-shaped members (third base materials) 243 each having a reflective film (third reflective film) 253 that reflects red light LR, and is configured with, for example, four plate-shaped members 243. The spectral reflectance of the reflective film 251 of the light guide element 141, the spectral reflectance of the reflective film 252 of the light guide element 142, and the spectral reflectance of the reflective film 253 of the light guide element 143 are the same.

[0139] In the projector 301 of this embodiment, a reflective structure such as a common dielectric multilayer film is formed as the reflective films 251, 252, and 253, and preferably, members made of a common material are used for the plate-like members 241, 242, and 243 that are elements that constitute the light guide elements 141, 142, and 143. According to the projector 301 of this embodiment, it is possible to reduce the time, effort, and cost required to manufacture the light guide elements 141, 142, and 143.

[0140] In the projector 301 of this embodiment, the light guide elements 141, 142, and 143 contain at least one of Al, Ag, and glass.

[0141] Al and Ag have a high reflectance of approximately 90% or more in the visible wavelength range, and exhibit excellent spectral reflectance when used as the plate-shaped members of the light guide elements 141, 142, and 143. In the projector 301 of this embodiment, if Al or Ag is used as the material for the plate-shaped members 241, 242, and 243, the spectral reflectance in the visible wavelength range common to the light guide elements 141, 142, and 143 can be easily achieved by correcting the spectral reflectance of the light guide elements 141, 142, and 143 based on the spectral reflectance of Al or Ag. Furthermore, Al and Ag have excellent heat dissipation and heat resistance, and therefore can form the light guide elements 141, 142, and 143 having these excellent properties. Glass is easy to mold and has high surface precision. In the projector 301 of this embodiment, if glass is used as the material for the plate-like members 241, 242, and 243, the shape precision of the light guide elements 141, 142, and 143 is improved, and the characteristics of the reflective films 251, 252, and 253 are ensured. According to the projector 301 of this embodiment, the light guide elements 141, 142, and 143 are configured to have excellent heat dissipation properties and heat resistance, which makes it easier to design the reflective films 251, 252, and 253, and ensures optical characteristics including spectral reflectance.

[0142] In the projector 301 of this embodiment, the light guide elements 141, 142, and 143 have the same shape.

[0143] If the light guide elements 141, 142, and 143 have a common shape, if the plate-like members 241, 242, and 243 are made of a common material, and if the reflective films 251, 252, and 253 are made of a common material and structure, the light guide elements 141, 142, and 143 can be made of common materials and members. According to the projector 301 of this embodiment, the manufacturing time, effort, and manufacturing cost of the light guide elements 141, 142, and 143 can be reduced.

[0144] In the projector 301 of this embodiment, the cross-sectional shapes of the light guide elements 141 and 143 perpendicular to the optical axis and the D1 direction are rectangular, and the cross-sectional shape of the light guide element 142 perpendicular to the optical axis and the D2 direction is rectangular.

[0145] The projector 301 of this embodiment can easily generate rectangular blue light LB, green light LG, and red light LR with uniform illuminance in a plane perpendicular to the optical axis of the colored light by the light guide elements 141, 142, and 143. The projector 301 of this embodiment can easily generate rectangular colored light that matches the modulation surfaces of the light modulation elements 181, 182, and 183.

[0146] 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 incident 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 incident 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 incident end 143a of the light guide element 143.

[0147] In the projector 301 of this embodiment, the illuminance distributions of the blue light LB, green light LG, and red light LR are uniformized and the irradiation area of ​​each color light is expanded from the time when they enter the light guide elements 141 a, 142 a, and 143 a through the incident ends 141 b, 142 b, and 143 b and exit through the exit ends 141 b, 142 b, and 143 b. According to the projector 301 of this embodiment, the illuminance distributions of the blue light LB, green light LG, and red light LR emitted from the light sources 121, 122, and 123 can be uniformized in a plane perpendicular to the optical axis, and the sizes of the blue light LB, green light LG, and red light LR in the plane perpendicular to the optical axis, i.e., the irradiation areas, can be easily expanded to match the modulation surfaces of the light modulation elements 181, 182, and 183.

[0148] In the projector 301 of this embodiment, the distance in the D1 direction from the incident end 141a to the exit end 141b of the light guide element 141 is 5 mm or more and 25 mm or less. The distance in the D2 direction from the incident end 142a to the exit end 142b of the light guide element 142 is 5 mm or more and 25 mm or less. The distance in the D1 direction from the incident end 143a to the exit end 143b of the light guide element 143 is 5 mm or more and 25 mm or less.

[0149] In the projector 301 of this embodiment, the lengths of the light-guiding elements 141, 142, and 143 in the direction along the optical axis of the colored light are appropriately set, so that the illuminance distribution in the plane perpendicular to the optical axis of each of the blue light LB, green light LG, and red light LR guided by the light-guiding elements 141, 142, and 143 can be efficiently uniformed, and the blue light LB, green light LG, and red light LR can be expanded.

[0150] In the projector 301 of this embodiment, the incident end 141a of the light guide element 141 has a width (dimension) d1 in the direction D2 along the long side of the opening API 141 through which the blue light LB enters. The width d1 of the incident end 141a is 1 mm or more and 3 mm or less. The exit end 141b of the light guide element 141 has a width (dimension) d2 in the direction D2 along the long side of the opening APE 141 through which the blue light LB exits. The width d2 of the exit end 141b is 14 mm or more and 16 mm or less. The incident end 142a of the light guide element 142 has a width (dimension) in the direction D1 along the long side of the opening API 142 through which the green light LG enters. The width of the incident end 142a in the direction D1 is 1 mm or more and 3 mm or less. The exit end 142b of the light-guiding element 142 has a width (dimension) in the D1 direction along the long side of the opening APE142 through which the green light LG is emitted. The width of the exit end 142b in the D1 direction is 14 mm or more and 16 mm or less. The incident end 143a of the light-guiding element 143 has a width (dimension) in the D2 direction along the long side of the opening through which the red light LR is incident. The width of the incident end 143a in the D2 direction is 1 mm or more and 3 mm or less. The exit end 143b of the light-guiding element 143 has a width (dimension) in the D2 direction along the long side of the opening through which the red light LR is emitted. The width of the exit end 143b in the D2 direction is 14 mm or more and 16 mm or less.

[0151] In the projector 301 of this embodiment, the widths of the incident end 141a and the exit end 141b of the light guide element 141 are appropriately set. Similarly, the widths of the incident end 142a and the exit end 142b of the light guide element 142 are appropriately set, and the widths of the incident end 143a and the exit end 143b of the light guide element 143 are appropriately set. According to the projector 301 of this embodiment, it is possible to increase the extraction efficiency of the blue light LB and the efficiency of uniforming the illuminance distribution in the light guide element 141. Furthermore, according to the projector 301 of this embodiment, it is possible to increase the extraction efficiency of the green light LG and the efficiency of uniforming the illuminance distribution in the light guide element 142, and it is possible to increase the extraction efficiency of the red light LR and the efficiency of uniforming the illuminance distribution in the light guide element 143.

[0152] In the projector 301 of this embodiment, the gradient angles of the side surfaces 141s, 142s, and 143s including the short sides of the light guide elements 141, 142, and 143, i.e., the angle α formed with respect to the optical axis, are 7° or more and 22° or less. The gradient angles of the side surfaces 141s, 142s, and 143s including the long sides of the light guide elements 141, 142, and 143, i.e., the angle β formed with respect to the optical axis, are 14° or more and 36° or less.

[0153] In the projector 301 of this embodiment, blue light LB, green light LG, and red light LR are emitted from the light sources 121, 122, and 123 and radially enter the light guide elements 141, 142, and 143 from the incident ends 141a, 142a, and 143a at a predetermined angle relative to the optical axis. The projector 301 of this embodiment minimizes loss of the blue light LB, green light LG, and red light LR in the light guide elements 141, 142, and 143, thereby improving the utilization efficiency of the blue light LB, green light LG, and red light LR. The projector 301 of this embodiment can improve the efficiency of uniforming the illuminance distribution of the blue light LB, green light LG, and red light LR in the light guide elements 141, 142, and 143.

[0154] In the projector 301 of this embodiment, the light sources 121 and 122 contain a GaN-based semiconductor material as a light emitter. The light source 123 contains AlGaInP as a light emitter. The light source 122 has a phosphor 124, and green light LG is emitted from the phosphor 124. The light source 121 that emits blue light LB and the light source 123 that emits red light LR are equipped with LEDs or LDs without containing a phosphor. Therefore, it is highly likely that the luminous efficiency of the green light LG emitted from the light source 122 is lower than the luminous efficiency of the blue light LB emitted from the light source 121 and the luminous efficiency of the red light LR emitted from the light source 123. If the wavelength band with the maximum reflectance in the spectral reflectance of the reflective films 251, 252, and 253 is the green wavelength band, even if the luminous efficiency of the light source 122 is lower than the luminous efficiency of the light sources 121 and 123, the difference in luminous efficiency between the light sources can be corrected by the difference in reflectance of color light in the light-guiding elements 141, 142, and 143, and image light IM with high color reproducibility and good color balance and brightness can be projected.

[0155] However, depending on the characteristics of the materials, the amount of red light LR emitted from the light source 123 containing AlGaInP may be relatively smaller than the amount of blue light LB emitted from the light source 121 containing a GaN-based semiconductor material and the amount of green light LG emitted from the light source 122 containing a GaN-based semiconductor material. As a modified design example of the projector 301 of this embodiment, the wavelength band with the maximum reflectance among the spectral reflectances of the light guide elements 141, 142, and 143 and the reflective films 251, 252, and 253 may be the red wavelength band. According to this modified design example of the projector 301 of this embodiment, even if the luminous efficiency of the red light LR from the light source 123 is lower than the luminous efficiency of the blue light LB from the light source 121 and the luminous efficiency of the red light LR from the light source 123, the difference in luminous efficiency between the light sources is corrected by the difference in the reflectance of the color light in the light guide elements 141, 142, and 143, and image light IM with high color reproducibility and good color balance and brightness can be projected.

[0156] 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 as described in the claims.

[0157] For example, in the blue light emitting unit 101 and the red light emitting unit 103, the LEDs constituting the light sources 121 and 123 may include a phosphor that is excited by light from the LED body and emits blue light LB and red light LR, similar to the green light emitting unit 102. Conversely, the LED of the light source 122 of the green light emitting unit 102 may not include the phosphor 124, and the light source 122 may be configured by an LED that directly emits green light LG. Furthermore, the polarization components transmitted by the incident-side polarizing plates arranged in the optical paths of the color lights may or may not be common components.

[0158] Summary of this disclosure A summary of this disclosure is provided below. (Supplementary Note 1) 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 first light-guiding 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, and that uniforms in-plane illuminance of the first light; a second light-guiding 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 emitted, and that uniforms in-plane illuminance of the second light; a first light modulation element that modulates the first light emitted from the second light guide element based on image information; a second light modulation element that modulates the second light emitted from the second light guide element based on image information; a light combining element that combines the first light emitted from the first light modulation element and the second light emitted from the second light modulation element and emits the combined light; and a projection optical system that projects the light emitted from the light combining element, wherein the spectral reflectance of the second light guide element is the same as the spectral reflectance of the first light guide element.

[0159] The configuration of Supplementary Note 1 eliminates the need for optical components used to generate white light or optical components for separating light into individual colored lights, thereby reducing the number of components and preventing the three-plate projector from becoming larger, thereby enabling a compact projector to be realized. The configuration of Supplementary Note 1 reduces the manufacturing time, labor, and cost of the first light guide element and the second light guide element.

[0160] (Supplementary Note 2) The projector of Supplementary Note 1 further includes: 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 third light guide element that has 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 that homogenizes in-plane illuminance of the third light; and a third light modulation element that modulates the third light emitted from the third light guide element based on image information, wherein the light combining element further combines and emits the third light emitted from the third light modulation element, and the spectral reflectance of the third light guide element is the same as the spectral reflectance of the first light guide element and the spectral reflectance of the second light guide element.

[0161] The configuration of Supplementary Note 2 reduces the number of parts, prevents the three-plate projector from becoming larger, and realizes a compact projector. The configuration of Supplementary Note 2 reduces the manufacturing time, labor, and manufacturing costs of the first light guide element, the second light guide element, and the third light guide element.

[0162] (Appendix 3) The projector of Appendix 2, wherein the first light is blue light, the second light is green light, and the third light is red light.

[0163] The configuration of Supplementary Note 3 makes it possible to generate image light with high color reproducibility.

[0164] (Appendix 4) The projector of Appendix 3, wherein the first wavelength band includes 467 nm, the second wavelength band includes 532 nm, and the third wavelength band includes 630 nm.

[0165] With the configuration of Supplementary Note 4, the first waveband, the second waveband, and the third waveband include the primary color wavelengths of BT.2020, a representative color standard, and therefore color reproduction can be compliant with the standard.

[0166] (Supplementary Note 5) The projector according to Supplementary Note 4, wherein the wavelength range in which the spectral reflectance of the first light guide element is at its maximum includes 555 nm.

[0167] With the configuration of Supplementary Note 5, the wavelength at which the spectral reflectance of the first light guide element is at its maximum coincides with the wavelength at which human visibility is at its maximum, thereby improving the visibility of the projected image.

[0168] (Supplementary Note 6) The projector according to any one of Supplementary Notes 3 to 5, wherein the first light source and the second light source contain a gallium nitride semiconductor material, the third light source contains aluminum gallium indium phosphide, the wavelength band in which the spectral reflectance of the first light guide element has the maximum reflectance is a red wavelength band, the wavelength band in which the spectral reflectance of the second light guide element has the maximum reflectance is a red wavelength band, and the wavelength band in which the spectral reflectance of the third light guide element has the maximum reflectance is a red wavelength band.

[0169] The configuration of Appendix 6 makes it possible to improve the color balance and brightness of the projected image light even when the luminous efficiency of the third light in the third light source is lower than the luminous efficiency of the first light in the first light source and the luminous efficiency of the second light in the second light source.

[0170] (Appendix 7) The projector according to any one of Appendices 2 to 6, wherein the first light-guiding element has a plurality of first substrates having a first reflective film that reflects the first light, the second light-guiding element has a plurality of second substrates having a second reflective film that reflects the second light, and the third light-guiding element has a plurality of third substrates having a third reflective film that reflects the third light, and the first reflective film, the second reflective film, and the third reflective film have the same spectral reflectance.

[0171] The configuration of Supplementary Note 7 allows the first light guide element, the second light guide element, and the third light guide element to use the same components, making it possible to easily manufacture these light guide elements and reduce manufacturing costs.

[0172] (Supplementary Note 8) The projector according to any one of Supplementary Note 1 to Supplementary Note 7, wherein the first light guide element and the second light guide element include at least one of aluminum, silver, and glass.

[0173] The configuration of Supplementary Note 8 makes it possible to configure the first light guide element and the second light guide element with excellent heat dissipation properties and heat resistance, thereby facilitating the design of the first reflective film and the second reflective film and ensuring optical characteristics including spectral reflectance.

[0174] (Supplementary Note 9) The projector according to any one of Supplementary Notes 1 to 8, wherein the first light guide element and the second light guide element have the same shape.

[0175] According to the configuration of Supplementary Note 9, the first light guide element and the second light guide element are made of the same material and members, and the manufacturing time, effort, and cost can be reduced.

[0176] (Supplementary Note 10) The projector according to Supplementary Note 9, wherein the first light guide element has a rectangular cross-sectional shape, and the second light guide element has a rectangular cross-sectional shape.

[0177] The configuration of Supplementary Note 10 makes it possible to easily generate rectangular first and second lights with uniform illuminance distribution as illumination light.

[0178] (Supplementary Note 11) The projector of Supplementary Note 9 or Supplementary Note 10, wherein a cross-sectional area of ​​the first exit end is larger than a cross-sectional area of ​​the first entrance end, and a cross-sectional area of ​​the second exit end is larger than a cross-sectional area of ​​the second entrance end.

[0179] The configuration of Appendix 11 allows the size of the irradiation area of ​​the first light emitted from the first light source to be matched to the size of the modulation surface of the first light modulation element, making it easy to uniformize the illuminance distribution of the first light, and the size of the irradiation area of ​​the second light emitted from the second light source to be matched to the size of the modulation surface of the second light modulation element, making it easy to uniformize the illuminance distribution of the second light.

[0180] (Supplementary Note 12) The projector according to any one of Supplementary Note 9 to Supplementary Note 11, wherein the length from the first entrance end to the first exit end is 5 mm or more and 25 mm or less.

[0181] The configuration of Supplementary Note 12 makes it possible to efficiently uniformize the illuminance distribution of the first light emitted from the first light source, to efficiently uniformize the illuminance distribution of the second light emitted from the second light source, and to expand the first light and the second light toward the emission side.

[0182] (Appendix 13) The projector of Appendix 12, wherein the first incident end has a dimension along the long side of the opening through which the first light enters, the dimension of the first incident end being 1 mm or more and 3 mm or less, and the first exit end has a dimension along the long side of the opening through which the first light exits, the dimension of the first exit end being 14 mm or more and 16 mm or less.

[0183] The configuration of Supplementary Note 13 can improve the efficiency of taking in the first light into the first light guide element and the efficiency of uniforming the first light, and can improve the efficiency of taking in the second light into the second light guide element and the efficiency of uniforming the second light.

[0184] (Supplementary Note 14) The slope angle of the side surface including the short side of the first light guide element is 7° or more and 22° or less, The projector of Appendix 9, wherein a slope angle of a side surface including a long side of the first light guide element is 14° or more and 36° or less.

[0185] The configuration of Supplementary Note 14 can improve the efficiency of taking in the first light into the first light guide element and the efficiency of uniforming the first light, and can improve the efficiency of taking in the second light into the second light guide element and the efficiency of uniforming the second light. [Explanation of symbols]

[0186] 121...light source (first light source), 122...light source (second light source), 123...light source (third light source), 141...light guide element (first light guide element), 142...light guide element (second light guide element), 143...light guide element (third light guide element), 181...light modulation element (first light modulation element), 182...light modulation element (second light modulation element), 183...light modulation element (third light modulation element), 200...light combining element, 301...projector.

Claims

1. 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 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 emitting end from which the first light is emitted; 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 emitting end from which the second light is emitted; a first light modulation element that modulates the first light emitted from the first light guide element based on image information; a second light modulation element that modulates the second light emitted from the second light guide element based on image information; a light combining element that combines the first light emitted from the first light modulation element and the second light emitted from the second light modulation element and emits the combined light; a projection optical system that projects the light emitted from the light combining element; Equipped with The spectral reflectance of the second light guide element is the same as the spectral reflectance of the first light guide element. projector.

2. 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 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; a third light modulation element that modulates the third light emitted from the third light guide element based on image information; Furthermore, the light combining element further combines the third light beams emitted from the third light modulation element and emits the combined light; the spectral reflectance of the third light guide element is the same as the spectral reflectance of the first light guide element and the spectral reflectance of the second light guide element; The projector according to claim 1 .

3. the first light is blue light; the second light is green light; the third light is red light; The projector according to claim 2 .

4. the first wavelength band includes 467 nm; the second wavelength band includes 532 nm; the third wavelength band includes 630 nm; The projector according to claim 3 .

5. The wavelength band in which the reflectance is maximum in the spectral reflectance of the first light guide element includes 555 nm. The projector according to claim 4 .

6. the first light source and the second light source include a gallium nitride based semiconductor material; the third light source includes aluminum gallium indium phosphide; a wavelength band in which the reflectance of the first light guide element is maximum is a red wavelength band; a wavelength band in which the reflectance of the second light guide element is maximum is a red wavelength band; The wavelength band in which the reflectance is maximum in the spectral reflectance of the third light guide element is a red wavelength band.

5. The projector according to claim 3 or claim 4.

7. the first light guide element includes a plurality of first substrates each having a first reflective film that reflects the first light; the second light guide element includes a plurality of second substrates each having a second reflective film that reflects the second light; the third light guide element includes a plurality of third substrates each having a third reflective film that reflects the third light; the first reflective film, the second reflective film, and the third reflective film have the same spectral reflectance; The projector according to any one of claims 2 to 5.

8. the first light guide element and the second light guide element include at least one of aluminum, silver, and glass; The projector according to claim 1 .

9. The first light guide element and the second light guide element have the same shape. The projector according to claim 1 .

10. The first light guide element has a rectangular cross-sectional shape, The cross-sectional shape of the second light guide element is rectangular. The projector according to claim 9.

11. a cross-sectional area of ​​the first exit end is larger than a cross-sectional area of ​​the first entrance end; The cross-sectional area of ​​the second exit end is larger than the cross-sectional area of ​​the second entrance end. The projector according to claim 9.

12. a length from the first incident end to the first exit end of the optical fiber is 5 mm or more and 25 mm or less; The projector according to claim 9.

13. the first incident end has a dimension along a long side of an opening into which the first light is incident, the dimension of the first incident end is 1 mm or more and 3 mm or less; the first exit end has a dimension along a long side of an opening through which the first light is emitted, the dimension of the first emission end is equal to or greater than 14 mm and equal to or less than 16 mm; The projector according to claim 12.

14. a slope angle of a side surface including a short side of the first light guide element is equal to or greater than 7° and equal to or less than 22°; The inclination angle of the side surface including the long side of the first light guide element is 14° or more and 36° or less. The projector according to claim 9.

Images