Projector

Abstract

The invention provides a projector, which reduces the number of components and suppresses enlargement in a three-plate projector. In a projector of the present invention, first light of a first wavelength band emitted from a first light source passes through a first light guide element and a first parallelization element in this order and is incident on a light synthesis element. Second light of a second wave band emitted from the second light source sequentially passes through the second light guide element and the second parallelization element and enters the light synthesis element. Third light of a third wave band emitted from the third light source sequentially passes through the third light guide element and the third parallelization element and enters the light synthesis element. A first focal length of the first parallelization element is longer than a first length from a first incident end to a first exit end of the first light guide element, and a second focal length of the second parallelization element is longer than a second length from a second incident end to a second exit end of the second light guide element. A third focal length of the third parallelization element is longer than a third length from a third incident end to a third exit end of the third light guide element.

Description

Technical Field

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

[0002] In the past, as a light modulator that generates image light of each color of three primary colors, a projector having three liquid crystal panels, that is, a three-panel projector, is known. For example, Patent Document 1 discloses a projector that includes: a light source device having a light source unit and a separation and synthesis element; an illumination optical system; a color separation and synthesis optical system; and a projection optical system. The light source unit emits excitation light of a fluorescent body. The separation and synthesis element causes a part of the light emitted from the light source unit to be incident on the fluorescent body, and causes another part of the light emitted from the light source unit to be incident on a diffuser and reflected by the diffuser. The illumination optical system illuminates the light emitted from the light source device. The color separation and synthesis optical system performs color separation and color synthesis on the light emitted from the illumination optical system. The projection optical system amplifies the color-synthesized image light and projects it onto an image display surface such as a screen.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-079820

[0004] In the three-panel projector disclosed in Patent Document 1, after white light is generated by a light source device, the white light is separated into each color light by a color separation and synthesis optical system arranged at a later stage than the light source device. Therefore, the projector disclosed in Patent Document 1 needs to have a color separation and synthesis optical system in addition to the light source device. As a result, the number of components increases, which may lead to an increase in the size of the projector. That is, in a three-panel projector, a countermeasure to reduce the number of components and suppress the increase in size is desired. Summary of the invention

[0005] A projector according to one embodiment of the present invention comprises: a first light source that emits first light of a first wavelength band; a second light source that emits second light of a second wavelength band different from the first wavelength band; a third light source that emits third light of a third wavelength band different from the first wavelength band and the second wavelength band; a first light guide element that has a first incident end for the first light emitted from the first light source to be incident and a first exit end for emitting the first light, so that the in-plane illumination of the first light is uniform; a second light guide element that has a second incident end for the second light emitted from the second light source to be incident and a second exit end for emitting the second light, so that the in-plane illumination of the second light is uniform; a third light guide element that has a third incident end for the third light emitted from the third light source to be incident and a third exit end for emitting the third light, so that the in-plane illumination of the third light is uniform; and a first parallelizing element , which parallelizes the first light emitted from the first light guide element; a second parallelizing element, which parallelizes the second light emitted from the second light guide element; a third parallelizing element, which parallelizes the third light emitted from the third light guide element; a first light modulating element, which modulates the first light emitted from the first parallelizing element based on image information; a second light modulating element, which modulates the second light emitted from the second parallelizing element based on image information; a third light modulating element, which modulates the third light emitted from the third parallelizing element based on image information; a light synthesizing element, which synthesizes the first light emitted from the first light modulating element, the second light emitted from the second light modulating element, and the third light emitted from the third light modulating element and emits them; and a projection optical system, which projects the light emitted from the light synthesizing element. The first focal length of the first parallelizing element is longer than the first length from the first incident end to the first emission end, the second focal length of the second parallelizing element is longer than the second length from the second incident end to the second emission end, and the third focal length of the third parallelizing element is longer than the third length from the third incident end to the third emission end. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 This is a schematic diagram showing the structure of a projector according to one embodiment.

[0007] Figure 2 yes Figure 1 Schematic diagram of the green light emitting portion of the projector.

[0008] Figure 3 yes Figure 1 Schematic diagram of the green light emitting section and incident-side polarizing element of a projector.

[0009] Figure 4 yes Figure 1 Schematic diagram of the green light emitting section, incident-side polarization element, and light modulation element of the projector.

[0010] Figure 5 yes Figure 1 A schematic diagram of a modified example of the green light emitting portion of a projector.

[0011] Figure 6 yes Figure 1 A schematic diagram of a modified example of the green light emitting portion of a projector.

[0012] Figure 7 yes Figure 1 A schematic diagram of a modified example of the green light emitting portion of a projector.

[0013] Figure 8 yes Figure 1 A schematic diagram of a modified example of the green light emitting portion of a projector.

[0014] Fig. 9 yes Figure 1 Schematic diagram of the main parts of the green light emitting section of the projector.

[0015] Description of symbols

[0016] 121: light source (first light source); 122: light source (second light source); 123: light source (third light source); 141: light guiding element (first light guiding element); 142: light guiding element (second light guiding element); 143: light guiding element (third light guiding element); 161: parallelizing element (first parallelizing element); 162: parallelizing element (second parallelizing element); 163: parallelizing element (third parallelizing element); 181: light modulating element (first light modulating element); 182: light modulating element (second light modulating element); 183: light modulating element (third light modulating element); 200: photosynthesizing element; 301: projector. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each of the drawings, in order to make each component easier to see, the scale of the dimensions may be changed depending on the component.

[0018] First, refer to Figures 1 to 5 One embodiment of the present invention will be described. Figure 1 2 is a schematic diagram showing the structure of a projector 301 according to an embodiment of the present invention. The projector 301 is an image display device having three liquid crystal panels as light modulation devices, and is a so-called three-panel projector. Figure 1 As shown, the projector 301 has a blue light emitting unit 101, a green light emitting unit 102, a red light emitting unit 103, incident-side polarization elements 171, 172, 173, light modulation elements 181, 182, 183, emitting-side polarization elements 175, 176, 177, a photosynthetic element 200, and a projection optical system 250.

[0019] The blue light emitting section 101 emits blue light LB. In the following description, an axis parallel to the optical axis of the blue light LB emitted from the blue light emitting section 101 is set as the D1 direction. One side in the D1 direction is set as the -D1 side, and the side opposite to the -D1 side in the D1 direction is set as the +D1 side. A direction perpendicular to the D1 direction within a plane including the optical axis of the blue light LB is set as the D2 direction. One side in the D2 direction is set as the -D2 side, and the side opposite to the -D2 side in the D2 direction is set as the +D2 side. A direction perpendicular to the D1 direction and the D2 direction is set as the D3 direction. The blue light LB emitted from the blue light emitting section 101 travels toward the +D1 side along the D1 direction.

[0020] The blue light emitting unit 101 includes a light source 121, a light guide element 141, and a parallelizing element 161. The light source 121 is supported by a substrate 111. The light source 121 is disposed on the substrate 111 on a plate surface on the +D1 side of a plate surface parallel to a surface including the D2 direction and the D3 direction. The light emitting surface of the light source 121 is arranged substantially parallel to the surface including the D2 direction and the D3 direction, and is a surface on the opposite side of the surface of the light source 121 in contact with the plate surface on the +D1 side of the substrate 111 in the D1 direction. The light source 121 is equivalent to a first light source, and emits blue light LB in a blue band in a visible band. The blue band is equivalent to a first band. The blue light LB is equivalent to the first light. The blue light LB is divergent from the light emitting surface of the light source 121 according to a predetermined radiation angle, with an axis passing through the center of the light emitting surface of the light source 121 and parallel to the D1 direction, and is emitted to the +D1 side. The blue band is, for example, a band of 420 nm to 500 nm.

[0021] The light source 121 is composed of, for example, a light emitting diode (LED) that emits blue light LB. In addition, 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.

[0022] The substrate 111 is made of metal, for example, and also functions as a heat dissipation member that receives heat from the light source 121 that emits the blue light LB and releases the heat to an external space.

[0023] The light guide element 141 is disposed on the optical path of the blue light LB emitted from the light source 121, and is arranged at a position closer to the +D1 side than the light source 121 and overlapping with the light source 121 in the D2 direction and the D3 direction. The light guide element 141 is equivalent to a first light guide element, and has an incident end 141a on the -D1 side of the D1 direction, an emission end 141b on the +D1 side, and a side surface 141s and a reflection surface 141r extending between the incident end 141a and the emission end 141b in the D1 direction. The incident end 141a is equivalent to a first incident end, and extends parallel to a plane including the D2 direction and the D3 direction. 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, for example, a rectangle. The size of the incident end 141a in the plane including the D2 direction and the D3 direction may be equal to the size of the light emitting surface of the light source 121 in the plane including the D2 direction and the D3 direction, but is preferably moderately larger than the size of the light emitting surface of the light source 121 in the plane including the D2 direction and the D3 direction. The emission end 141b corresponds to the first emission end, extends parallel to the plane including the D2 direction and the D3 direction, and is larger than the incident end 141a. The shape of the emission end 141b when viewed from the D1 direction is the same as the modulation surface of the light modulator 181 when viewed from the same direction, for example, a rectangle. The size of the emission end 141b in the plane including the D2 direction and the D3 direction is equal to the size of the modulation surface of the light modulator 181 in the plane including the D2 direction and the D3 direction. The side surface 141s and the reflection surface 141r connect the peripheral portion of the incident end 141a and the peripheral portion of the emission end 141b in the D1 direction.

[0024] The blue light LB emitted from the light source 121 enters the light guide element 141 from the incident end 141a. In the light guide element 141, the area surrounded by the incident end 141a, the emission end 141b and the reflection surface 141r is the area that propagates the blue light LB. The size of the area surrounded by the incident end 141a, the emission end 141b and the reflection surface 141r in the plane including the D2 direction and the D3 direction increases as it moves from the -D1 side to the +D1 side of the D1 direction. In addition, as it moves from the -D1 side to the +D1 side, the shape of the area surrounded by the incident end 141a, the emission end 141b and the reflection surface 141r on the plane including the D2 direction and the D3 direction changes from the shape of the light emitting surface of the light source 121 when viewed from the D1 direction to the shape of the modulation surface of the light modulation element 181.

[0025] The side surface 141s of the light guide element 141 and the reflecting surface 141r provided on the side surface 141s as described later form a predetermined angle with respect to the imaginary line perpendicular to the incident end 141a and the optical axis, and move away from the imaginary line in a plane including the D2 direction and the D3 direction as moving 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 in the area surrounded by the incident end 141a, the emission end 141b, and the reflecting surface 141r.

[0026] When the shape of the modulation surface of the light modulator 181 when observed along the D1 direction is a rectangle, the shape of the light emitting surface of the light source 121 when observed along the D1 direction is also consistent with the rectangle. In this case, the prescribed angle α, that is, the cone angle, formed by the side surface 141s and the reflecting surface 141r including the short side of the rectangle relative to the above-mentioned imaginary line and the optical axis is preferably in the range of 7° to 22°. The prescribed angle β, that is, the cone angle, formed by the side surface 141s and the reflecting surface 141r including the long side of the rectangle relative to the above-mentioned imaginary line and the optical axis is preferably in the range of 14° to 36°. The preferred ranges of the angles α and β are confirmed by numerical simulation based on the structure of the blue light emitting portion 101 and ray tracing.

[0027] A portion of the blue light LB incident on the light guide element 141 forms an angle smaller than a specified angle with respect to the aforementioned virtual axis and the optical axis, and does not enter the reflection surface 141r once, but directly propagates from the incident end 141a to the emission end 141b. The remaining portion of the blue light LB incident on the light guide element 141 forms an angle greater than a specified angle with respect to the aforementioned virtual axis and the optical axis, enters the reflection surface 141r from the incident end 141a more than one time, and reaches the emission end 141b after being reflected by the reflection surface 141r. The path of the blue light LB in the area surrounded by the incident end 141a, the emission end 141b, and the reflection surface 141r varies depending on the angle of incidence to the incident end 141a, involving multiple paths with different numbers of reflections at the reflection surface 141r. Thus, the illuminance distribution of the blue light LB propagating in the area surrounded by the incident end 141a, the emission end 141b and the reflection surface 141r is uniformed in the plane including the D2 direction and the D3 direction. That is, the light guide element 141 makes the illuminance distribution of the incident blue light LB uniform in the plane including the D2 direction and the D3 direction. The blue light LB with uniform illuminance distribution is emitted from the emission end 141b to the +D1 side.

[0028] The light guide element 141 is a reflector made of a transparent material such as optical glass. The reflector has a frame and is formed as a hollow component. When viewed along the D1 direction, the end of the reflector frame on the -D1 side has the same shape and size as the incident end 141a and the light emitting surface of the light source 121, for example, it is formed into a rectangular frame. The end of the reflector frame on the +D1 side has the same shape and size as the emission end 141b and the modulation surface of the light modulation element 181, for example, it is formed into a rectangular frame of a size different from that of the end on the -D1 side.

[0029] The reflector is formed, for example, by a plate-like component made of a transparent material. As described above, if the shape of the incident end 141a and the emission end 141b when viewed from the D1 direction is a rectangle, the reflector is formed by four plate-like components having a trapezoidal shape. The length of the side parallel to the D2 direction or the D3 direction on the -D1 side corresponding to the upper base of the four plate-like components is set according to the size of the incident end 141a and the light-emitting surface of the light source 121 in the D2 direction or the D3 direction. The length of the side parallel to the D2 direction or the D3 direction on the +D1 side corresponding to the lower base of the four plate-like components is set according to the size of the emission end 141b and the modulation surface of the light modulation element 181 in the D2 direction or the D3 direction. Among the four plate-like components, the side of one of the two plate-like components corresponding to the leg on one side is connected to the side of the other plate-like component corresponding to the leg on the other side.

[0030] As described above, when the reflector is formed by a plate-like member formed by a transparent member, the side surface 141s, that is, the plate surface of the plate-like member facing the external space of the reflector functions as a reflection surface 141r. In the reflector of the light guide element 141, in order to increase the reflectivity of the blue light LB incident on the light guide element 141 from the incident end 141a near the side surface 141s, a reflection film 251 composed of a dielectric multilayer film or the like is provided on the plate surface of the plate-like member constituting the reflector facing the internal space. A portion of the blue light LB incident on the internal space of the reflector of the light guide element 141 from the incident end 141a is reflected by the reflection film 251 and travels to the +D1 side.

[0031] The intensity of the blue light LB reflected by the reflective film 251 and emitted from the reflective film 251 sometimes depends on the incident angle of the blue light LB incident on the reflective film 251. In the case where the reflective film 251 is composed of a dielectric multilayer film, for example, the incident angle dependence of the intensity of the blue light LB emitted from the reflective film 251 changes according to parameters such as the refractive index of the plurality of films included in the dielectric multilayer film, the thickness of the film, and the number of films. As described above, for example, when the angle α is in the range of 7° to 22° and the angle β is in the range of 14° to 36°, the reflective film 251 is designed so that the incident angle of the blue light LB with the highest intensity emitted from the reflective surface 141r is in the range of 60° to 90°, and the parameters of the dielectric multilayer film are appropriately determined. The relationship between the incident angle of the blue light LB to the reflective surface 141r and the reflective film 251 and the intensity of the blue light LB emitted from the reflective surface 141r and the reflective film 251 is obtained by numerical simulation based on the structure of the blue light emitting unit 101 and ray tracing.

[0032] In addition, when the reflector is composed of a plate-like component composed of a transparent component, and the plate surface of the plate-like component facing the external space of the reflector acts as a reflecting surface 141r, a portion of the blue light LB that is incident on the internal space of the reflector of the light-guiding element 141 from the incident end 141a is incident on the plate-like component from the plate surface of the plate-like component facing the internal space of the reflector and is refracted, is reflected by the plate surface facing the external space of the reflector, propagates again in the plate-like component, is refracted by the plate surface facing the internal space of the reflector, is emitted into the internal space of the reflector, and travels toward the +D1 side.

[0033] The parallelization element 161 is disposed on the optical path of the blue light LB emitted from the light guide element 141, and is arranged at a position closer to the +D1 side than the light guide element 141 and overlapping with the light guide element 141 in the D2 direction and the D3 direction. The parallelization element 161 is equivalent to a first parallelization element, and parallelizes the blue light LB emitted from the light guide element 141 along the D1 direction.

[0034] The parallelizing element 161 is, for example, a plano-convex lens, and has an incident surface composed of a flat surface perpendicular to the D1 direction and an exit surface composed of a convex surface protruding toward the exit side of the blue light LB. The focal point of the plano-convex lens constituting the parallelizing element 161 is located at least on the -D1 side of the parallelizing element 161 and on the side opposite to the +D1 side from which the blue light LB is emitted from the parallelizing element 161, and further on the -D1 side of the light guiding element 141. The incident surface of the plano-convex lens of the parallelizing element 161 is in contact with the exit end 141b of the light guiding element 141. By making the parallelizing element 161 in contact with the exit end 141b, the blue light LB emitted from the exit end 141b of the light guiding element 141 is taken into the parallelizing element 161 to the maximum extent, and the loss of the blue light LB can be suppressed. However, the parallelizing element 161 may be an optical lens other than a plano-convex lens capable of parallelizing the incident blue light LB, and may be disposed at an appropriate interval from the light guide element 141 in the D1 direction.

[0035] The focal length f1 of the parallelization element 161 is equivalent to the first focal length, which is longer than the length g1 from the incident end 141a to the emission end 141b of the light-guiding element 141 in the direction D1. The length g1 is equivalent to the first length. Specifically, the focal length f1 of the parallelization element 161 is preferably greater than 1.1 times the length g1 of the light-guiding element 141. The focal length f1 is more preferably greater than 1.1 times the length g1 and less than 2.0 times the length g1. By setting the focal length f1 within the above range, the blue light LB emitted from the light source 121 is efficiently parallelized, and the utilization efficiency of the blue light LB is improved. The preferred range of the focal length f1 is confirmed by numerical simulation based on the structure of the blue light emitting portion 101 and ray tracing.

[0036] When the focal length f1 of the parallelization element 161 is shorter than 1.1 times the length g1 of the light guide element 141, the illumination range of the blue light LB emitted from the parallelization element 161 is excessively reduced, and when the image light converted by the subsequent light modulator 181 is projected and enlarged and displayed on the screen SC, a part of the original image may not be displayed. On the other hand, when the focal length f1 is longer than 2.0 times the length g1, a part of the blue light LB emitted from the parallelization element 161 will not be incident on the light modulator 181 arranged at a later stage than the parallelization element 161. As a result, the utilization efficiency of the blue light LB may be reduced.

[0037] The incident side polarization element 171 is disposed on the optical path of the blue light LB emitted from the parallelization element 161, and is arranged at a position closer to the +D1 side than the parallelization element 161 and overlapping with the parallelization element 161 in the D2 direction and the D3 direction. The incident side polarization element 171 contacts the light modulator 181, for example, from the -D1 side, but can also be arranged at an appropriate interval from the light modulator 181 in the D1 direction. The incident side polarization element 171 is equivalent to a first polarization element, which causes a specified polarized light in the blue light LB emitted from the parallelization element 161 to be emitted toward the +D1 side along the D1 direction. The specified polarized light is equivalent to the first polarized light component, for example, S polarized light. The incident side polarization element 171 is, for example, a reflective polarizer having a plate surface parallel to a surface including the D2 direction and the D3 direction. The incident side polarization element 171 causes a portion of the incident blue light LB including the specified polarized light to pass toward the +D1 side, and reflects another portion of the blue light LB toward the -D1 side.

[0038] The light modulator 181 is disposed on the optical path of the blue light LB emitted from the incident-side polarizer 171, and is disposed at a position closer to the +D1 side than the incident-side polarizer 171 and overlapping with the incident-side polarizer 171 in the D2 direction and the D3 direction. The light modulator 181 is equivalent to a first light modulator, and modulates the blue light LB emitted from the incident-side polarizer 171 according to image information sent from an image forming device such as a computer (not shown) externally connected to the light modulator 181.

[0039] The light modulator 181 is, for example, a transmissive liquid crystal panel. The liquid crystal panel constituting the light modulator 181 has a plurality of pixels not shown. Each pixel is provided with a switching element. The switching element is, for example, a polysilicon thin film transistor (TFT). An electrical signal corresponding to the brightness of the blue light at the relative position of each pixel in the modulation surface of the light modulator 181 in the image projected by the projector 301 is supplied to the switching element of each pixel. Each pixel modulates the vibration direction of the blue light LB incident from the incident side polarization element 171 by the action of the switching element corresponding to the above-mentioned electrical signal, thereby generating a blue image light IB. The image light IB is equivalent to the first light. The light modulator 181 emits the image light IB generated by the liquid crystal panel to the +D1 side along the D1 direction.

[0040] The emission-side polarization element 175 is disposed on the optical path of the image light IB emitted from the light modulator 181, and is arranged at a position closer to the +D1 side than the light modulator 181 and overlapping with the light modulator 181 in the D2 direction and the D3 direction. The emission-side polarization element 175 contacts the light modulator 181 from the +D1 side, for example, but may also be arranged at an appropriate interval from the light modulator 181 in the D1 direction. The emission-side polarization element 175 is equivalent to a fourth polarization element, and emits a specified polarization light in the image light IB emitted from the light modulator 181 to the +D1 side along the D1 direction. The specified polarization light is equivalent to the fourth polarization light component, for example, P polarization light. The emission-side polarization element 175 is, for example, a reflective polarizer or an absorptive polarizer having a plate surface parallel to a surface including the D2 direction and the D3 direction. In addition, in the case where it is desired to suppress return light and stray light to the light modulator 181, it is preferable to use an absorptive polarizer as the emission-side polarization element 175. The output-side polarization element 175 transmits a portion of the incident image light IB including predetermined polarized light toward the +D1 side, and reflects the other portion of the image light IB toward the −D1 side.

[0041] The green light emitting section 102 is arranged closer to the +D1 side and the -D2 side than the blue light emitting section 101, and is arranged in a region overlapping the blue light emitting section 101 in the D3 direction. The green light emitting section 102 emits green light LG. The green light LG emitted from the green light emitting section 102 travels toward the +D2 side along the D2 direction.

[0042] The green light emitting unit 102 includes a light source 122 , a light guide element 142 , and a parallelizing element 162 . Figure 2 2 is a schematic diagram of the green light emitting section 102 , and is a diagram when the green light emitting section 102 is viewed along the direction D3 . Figure 3 1 is a schematic diagram of the green light emitting section 102 and the incident-side polarizing element 172, and is a diagram when the green light emitting section 102 and the incident-side polarizing element 172 are observed along the D3 direction. Figures 1 to 3 As shown, the light source 122 is supported by the substrate 112. The light source 122 is provided on the substrate 112 on the board surface on the +D2 side of the board surface parallel to the surface including the D1 direction and the D3 direction. The light emitting surface 122a of the light source 122 is arranged substantially parallel to the surface including the D1 direction and the D3 direction, and is the surface on the opposite side of the surface of the light source 122 in contact with the board surface on the +D2 side of the substrate 112 in the D2 direction. The light source 122 is equivalent to the second light source, and emits green light LG in the green band in the visible band. The green band is, for example, a band of 500nm to 600nm.

[0043] The light source 122 is composed of, for example, an LED that emits green light LG. In the green light emitting section 102, in order to optimize the green wavelength band and intensity of the green light LG relative to the blue wavelength band and intensity of the blue light LB emitted by the blue light emitting section 101 and the red wavelength band and intensity of the red light LR emitted by the red light emitting section 103, the light source 122 is composed of an LED with a built-in phosphor, and has an LED main body 125 and a phosphor 124 composed of a semiconductor. The LED main body 125 is provided on the board surface on the +D2 side of the substrate 112. The LED main body 125 may also be, for example, an LED that emits blue light LB like the light source 121. The phosphor 124 is stacked on the emission surface 125a on the +D2 side of the LED main body 125. The phosphor 124 is excited by the light emitted from the LED main body 125 as excitation light, and emits the 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.

[0044] The light source 122 may be composed of one LED or a plurality of LEDs as in the case of the light source 121. When the light source 122 is composed of a plurality of LEDs, the plurality of LEDs are arranged in a region occupied by the light source 122 in a plane including the directions D1 and D3.

[0045] The substrate 112 is made of metal, for example, and also functions as a heat dissipation member that receives heat from the light source 122 that emits the green light LG and releases the heat to an external space.

[0046] The light guide element 142 is disposed on the optical path of the green light LG emitted from the light source 122, and is arranged at a position closer to the +D2 side than the light source 122 and overlapping with the light source 122 in the D1 direction and the D3 direction. The light guide element 142 is equivalent to a second light guide element, and has an incident end 142a on the -D2 side of the D2 direction, an emission end 142b on the +D2 side, and a side surface 142s and a reflection surface 142r extending between the incident end 142a and the emission end 142b in the D2 direction. The incident end 142a is equivalent to a second incident end, and extends parallel to a plane including the D1 direction and the D3 direction. The shape of the incident end 142a when viewed from the D2 direction is the same as the shape of the light emitting surface 122a of the light source 122 when viewed from the same direction, for example, a rectangle. The size of the incident end 142a in the plane including the D1 direction and the D3 direction may be equal to the size of the light emitting surface 122a of the light source 122 in the plane including the D1 direction and the D3 direction, but is preferably moderately larger than the size of the light emitting surface 122a in the plane including the D1 direction and the D3 direction. The emission end 142b corresponds to the second emission end, extends parallel to the plane including the D1 direction and the D3 direction, and is larger than the incident end 142a. The shape of the emission end 142b when viewed from the D2 direction is the same as the modulation surface of the light modulator 182 when viewed from the same direction, for example, a rectangle. The size of the emission end 142b in the plane including the D1 direction and the D3 direction is equal to the size of the modulation surface of the light modulator 182 in the plane including the D1 direction and the D3 direction. The side surface 142s and the reflection surface 142r connect the peripheral portion of the incident end 142a and the peripheral portion of the emission end 142b in the D2 direction.

[0047] The green light LG emitted from the light source 122 enters the light guide element 142 from the incident end 142a. In the light guide element 142, the area surrounded by the incident end 142a, the emission end 142b, and the reflection surface 142r is the area that propagates the green light LG. The size of the area surrounded by the incident end 142a, the emission end 142b, and the reflection surface 142r in the plane including the D1 direction and the D3 direction increases as it moves from the -D2 side to the +D2 side of the D2 direction. In addition, as it moves from the -D2 side to the +D2 side, the shape of the area surrounded by the incident end 142a, the emission end 142b, and the reflection surface 142r in the plane including the D1 direction and the D3 direction changes from the shape of the light emitting surface 122a of the light source 122 when viewed from the D2 direction to the shape of the modulation surface of the light modulation element 182.

[0048] The side surface 142s of the light guide element 142 and the reflecting surface 142r provided on the side surface 142s as described later form a predetermined angle with respect to the imaginary line VX perpendicular to the incident end 142a and the optical axis, and move away from the imaginary line in a plane including the D2 direction and the D3 direction as moving from the -D2 side to the +D2 side. The green light LG incident on the light guide element 142 propagates from the -D2 side to the +D2 side in the area surrounded by the incident end 142a, the emission end 142b, and the reflecting surface 142r.

[0049] When the shape of the modulation surface of the light modulator 182 when viewed along the D2 direction is a rectangle, the shape of the light emitting surface 122a of the light source 122 when viewed along the D2 direction is also consistent with the rectangle. In this case, the side surface 142s including the short side of the rectangle and the reflection surface 142r with respect to the above-mentioned imaginary line and the optical axis preferably form a predetermined angle α in the range of 7° to 22°. The side surface 142s including the long side of the rectangle and the reflection surface 142r with respect to the above-mentioned imaginary line and the optical axis preferably form a predetermined angle β in the range of 14° to 36°.

[0050] A part of the light Lg1 of the green light LG incident on the light guide element 142 forms an angle smaller than the angle α or the angle β with respect to the imaginary axis VX and the optical axis, and does not enter the reflection surface 142r once, but directly propagates from the incident end 142a to the emission end 142b. The remaining part of the light Lg2 of the green light LG incident on the light guide element 142 forms an angle greater than the angle α or the angle β with respect to the imaginary axis VX and the optical axis, enters the reflection surface 142r from the incident end 142a once, is reflected by the reflection surface 142r, and reaches the emission end 142b. The remaining light of the green light LG incident on the light guide element 142, except for the part of the light Lg2, enters the reflection surface 142r from the incident end 142a more than two times, and reaches the emission end 142b after being repeatedly reflected by the reflection surface 142r. The path of the green light LG in the area surrounded by the incident end 142a, the emission end 142b and the reflection surface 142r is different depending on the incident angle to the incident end 142a, involving multiple paths with different numbers of reflections at the reflection surface 142r. As a result, the illuminance distribution of the green light LG propagating in the area surrounded by the incident end 142a, the emission end 142b and the reflection surface 142r is uniformized in the plane including the D1 direction and the D3 direction. That is, the light guide element 142 uniformizes the illuminance distribution of the incident green light LG in the plane including the D1 direction and the D3 direction. The green light LG with uniform illuminance distribution is emitted from the emission end 142b to the +D2 side.

[0051] The light guide element 142 is similar to the light guide element 141, and is a hollow reflector formed by a plate-like member made of a transparent material such as optical glass. When observed along the D2 direction, the end of the reflector frame on the -D2 side 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 into a rectangular frame shape, for example. The end of the reflector frame on the +D2 side has the same shape and size as the emission end 142b and the modulation surface of the light modulation element 182, and is formed into a rectangular frame shape of a size different from the end on the -D2 side.

[0052] The reflector of the light guide element 142 is formed by connecting the sides of the four plate-like parts corresponding to the legs to each other. The length of the side parallel to the D1 direction or the D3 direction on the -D2 side corresponding to the upper base of the four plate-like parts is set according to the size of the incident end 142a and the light emitting surface 122a in the D1 direction or the D3 direction. The length of the side parallel to the D1 direction or the D3 direction on the +D2 side corresponding to the lower base of the four plate-like parts is set according to the size of the emission end 142b and the modulation surface of the light modulation element 182 in the D1 direction or the D3 direction.

[0053] In the reflector of the light guide element 142, in order to improve the reflectivity of the green light LG incident on the light guide element 142 from the incident end 142a near the side surface 142s, a reflective film 252 such as a dielectric multilayer film is also provided on the plate surface of the plate-like member constituting the reflector on the side opposite to the side surface 142s, that is, the plate surface of the plate-like member facing the internal space. A part of the green light LG incident on the internal space of the reflector of the light guide element 142 from the incident end 142a, including the light Lg2, is reflected by the reflective film 252 and travels to the +D2 side.

[0054] The intensity of the green light LG reflected by the reflective film 252 and emitted from the reflective film 252 may depend on the incident angle of the green light LG incident on the reflective film 252. When the reflective film 252 is composed of a dielectric multilayer film, the incident angle dependency of the intensity of the green light LG emitted from the reflective film 252 changes, for example, depending on the parameters such as the refractive index, the thickness of the film, and the number of films included in the dielectric multilayer film. As described above, for example, when the angle α is in the range of 7° to 22° and the angle β is in the range of 14° to 36°, the reflective film 252 is designed so that the incident angle of the green light LG with the highest intensity emitted from the reflecting surface 142r and the reflective film 252 is within the range of 60° to 90°, and the parameters of the dielectric multilayer film are appropriately determined. The relationship between the incident angle of the green light LG to the reflective film 252 and the intensity of the green light LG emitted from the reflective film 252 is also obtained by numerical simulation based on the structure of the green light emitting unit 102 and ray tracing.

[0055] The parallelizing element 162 is disposed on the optical path of the green light LG emitted from the light guide element 142, and is arranged at a position closer to the +D2 side than the light guide element 142 and overlapping with the light guide element 142 in the D1 direction and the D3 direction. The parallelizing element 162 is equivalent to a second parallelizing element, and parallelizes the green light LG emitted from the light guide element 142 along the D2 direction.

[0056] The parallelizing element 162 is, for example, a plano-convex lens, and has an incident surface 162a formed of a flat surface perpendicular to the D2 direction and an exit surface 162b formed of a convex curved surface protruding toward the exit side of the green light LG. The focus F2 of the plano-convex lens constituting the parallelizing element 162 is at least located on the -D2 side of the parallelizing element 162, and on the side opposite to the +D2 side from which the green light LG is emitted from the parallelizing element 162, and further on the -D2 side of the light guide element 142. The incident surface 162a of the parallelizing element 162 is in contact with the exit end 142b of the light guide element 142. Since the parallelizing element 162 is in contact with the exit end 142b, the green light LG emitted from the exit end 142b of the light guide element 142 is taken into the parallelizing element 162 to the maximum extent, and the loss of the green light LG can be suppressed. However, the parallelizing element 162 may be an optical lens other than a plano-convex lens capable of parallelizing the incident green light LG, and may be arranged at an appropriate interval from the light guiding element 142 in the D2 direction.

[0057] The focal length f2 of the parallelizing element 162 corresponds to the second focal length and is longer than the length g2 from the incident end 142a to the emitting end 142b of the light guide element 142 in the direction D2. The length g2 corresponds to the second length.

[0058] like Figure 2As shown in detail, the light ray Lg1 of a part of the green light LG incident on the light guide element 142 does not enter the reflection surface 142r once, but propagates directly from the incident end 142a to the emission end 142b. The light ray Lg2 of the remaining part of the green light LG incident on the light guide element 142 enters the reflection surface 142r once from the incident end 142a, is reflected by the reflection surface 142r, and reaches the emission end 142b. Ignoring the effect of the parallelization element 162, the synthetic vector VG of the light rays Lg1 and Lg2 emitted from the emission end 142b to the +D2 side is represented by a dotted line. When the synthetic vector VG at the emission end 142b is extended from the base end on the -D2 side to the -D2 side in parallel with the synthetic vector VG, there is a focus F2 at a position where the center line of the plane including the D1 direction and the D3 direction of the parallelization element 162 and the light guide element 142 and the optical axis intersect. As described above, the path of the green light LG propagating inside the light guide element 142 is generated in addition to the paths of the light rays Lg1 and Lg2. When the synthetic vector of the multiple light rays included in the green light LG emitted from the emission end 142b to the +D2 side is extended to the -D2 side under the assumption that the effect of the parallelization element 162 is ignored, the position intersecting the center line and the optical axis of the parallelization element 162 and the light guide element 142 does not strictly converge to a point, but the focus F2 caused by the synthetic vector VG is dispersed in a small width area in the D2 direction. As a result, the focus F2 of the plano-convex lens of the parallelization element 162 is slightly expanded in the D2 direction, but it constitutes a point macroscopically.

[0059] In addition, similarly to the green light emitting section 102, in the above-mentioned blue light emitting section 101, when the synthetic vector of a plurality of light rays included in the blue light LB emitted from the emission end 141b to the +D1 side is extended to the -D1 side under the assumption that the effect of the parallelizing element 161 is ignored, the position intersecting the center line and the optical axis of the parallelizing element 161 and the light guide element 141 does not strictly converge to a single point, but is spread over a region of a small width in the D1 direction. As a result, the focus F1 of the plano-convex lens of the parallelizing element 161 slightly expands in the D1 direction, but constitutes a single point macroscopically.

[0060] Since the focal length f2 of the parallelizing element 162 is set to be closer to -D2 than the light guide element 142 and longer than the length g2 of the light guide element 142 according to the position of the focal point F2 based on the above principle, the multiple light rays included in the green light LG are efficiently parallelized relative to the D2 direction as shown by the thick lines. Figure 2, the relationship between the focal length f2 of the parallelization element 162 and the length g2 of the light-guiding element 142, and the effects caused by the focal length f2 and the length g2 are explained, but the contents described are also applicable to the relationship between the focal length f1 of the parallelization element 161 of the above-mentioned blue light emitting portion 101 and the length g1 of the light-guiding element 141, and the effects caused by the focal length f1 and the length g1.

[0061] Specifically, the focal length f2 of the parallelization element 162 is preferably greater than or equal to 1.1 times the length g2 of the light guide element 142. The focal length f2 is more preferably greater than or equal to 1.1 times the length g2 and less than or equal to 2.0 times the length g2. By setting the focal length f2 within the above range, the green light LG emitted from the light source 122 is efficiently parallelized, and the utilization efficiency of the green light LG is improved. The preferred range of the focal length f2 is also confirmed by numerical simulation based on the structure of the green light emitting portion 102 and ray tracing.

[0062] If the focal length f2 of the parallelizing element 162 is shorter than 1.1 times the length g2 of the light guide element 142, the illumination range of the green light LG emitted from the parallelizing element 162 is excessively reduced, and when the image light is converted by the subsequent light modulating element 182 and projected and enlarged and displayed on the screen SC, a part of the original image may not be displayed. On the other hand, when the focal length f2 is longer than 2.0 times the length g2, a part of the green light LG emitted from the parallelizing element 162 will not be incident on the light modulating element 182 disposed at a later stage than the parallelizing element 162. As a result, the utilization efficiency of the green light LG may be reduced.

[0063] like Figures 1 to 3 As shown, the incident-side polarizing element 172 is provided on the optical path of the green light LG emitted from the parallelizing element 162, and is arranged at a position closer to the +D2 side than the parallelizing element 162 and overlapping with the parallelizing element 162 in the D1 direction and the D3 direction. The incident-side polarizing element 172 contacts the light modulating element 182 from the -D2 side, for example, but may also be arranged at an appropriate interval from the light modulating element 182 in the D2 direction.

[0064] The incident-side polarizing element 172 is equivalent to a second polarizing element, and causes a predetermined polarized light in the green light LG emitted from the parallelizing element 162 to be emitted toward the +D2 side along the D2 direction. The predetermined polarized light is equivalent to the second polarized light component, and is, for example, S polarized light. The incident-side polarizing element 172 is, for example, a reflective polarizing plate having a plate surface parallel to a surface including the D1 direction and the D3 direction. The incident-side polarizing element 172 causes a portion of the incident green light LG including the predetermined polarized light to pass toward the +D2 side, and reflects another portion of the green light LG toward the -D2 side.

[0065] like Figure 3As shown in detail, the green light LG emitted from the light source 122 is a randomly polarized light including at least P polarized light and S polarized light. The S polarized light component in the green light LG emitted from the light source 122, i.e., the green light LGS, and the P polarized light component in the green light LG, i.e., the green light LGP, pass through the light guide element 142, and the illumination distribution is uniformed in the plane including the D1 direction and the D3 direction by means of the light guide element 142, and are emitted to the +D2 side of the light guide element 142. The green light LGS and LGP pass through the parallelizing element 162 and are parallelized by the parallelizing element 162. The parallelized green light LGS and LGP are incident on the incident side polarizing element 172 from the -D2 side. The green light LGS passes through the incident side polarizing element 172 and is emitted to the +D2 side of the incident side polarizing element 172. The green light LGP is reflected by the incident surface 172a of the incident side polarizing element 172 and is emitted to the -D2 side of the incident side polarizing element 172.

[0066] The green light LGP reflected from the incident-side polarizing element 172 to the -D2 side passes through the parallelizing element 162 and the light guide element 142 in sequence, travels to the -D2 side along the D2 direction, converges in a plane including the D1 direction and the D3 direction, and enters the phosphor 124 of the light source 122 from the +D2 side. The phosphor 124 is excited again by the green light LGP emitted from the incident-side polarizing element 172 to the -D2 side, and emits the green light LG including the green light LGS and LGP to the +D2 side from the emission surface 124a. The incident-side polarizing element 172 is composed of a reflective polarizing plate, and thus the polarized light of the green light LG that does not pass through the incident-side polarizing element 172 enters the phosphor 124 of the light source 122 again, which contributes to the excitation and emission of the phosphor 124. As a result, the utilization efficiency of the green light LG in the green light emitting unit 102 and the projector 301 is improved.

[0067] The light modulator 182 is disposed on the optical path of the green light LG emitted from the incident-side polarizer 172, and is disposed at a position closer to the +D2 side than the incident-side polarizer 172 and overlapping with the incident-side polarizer 172 in the D1 direction and the D3 direction. The light modulator 182 is equivalent to a second light modulator, and modulates the green light LG emitted from the incident-side polarizer 172 based on image information sent from an image forming device such as a computer (not shown) externally connected to the light modulator 182.

[0068] The light modulator 182 is, for example, a transmissive liquid crystal panel. The liquid crystal panel constituting the light modulator 182 has a plurality of pixels not shown. Each pixel is provided with a switching element. The switching element is, for example, a TFT. An electrical signal corresponding to the brightness of the green light at the relative position of each pixel in the modulation surface of the light modulator 182 in the image projected by the projector 301 is supplied to the switching element of each pixel. Each pixel modulates the vibration direction of the green light LG incident from the incident side polarization element 172 by the action of the switching element corresponding to the above electrical signal, thereby generating green image light IG. The image light IG is equivalent to the second light. The light modulator 182 emits the image light IG generated by the liquid crystal panel to the +D2 side along the D2 direction.

[0069] The emission-side polarization element 176 is disposed on the optical path of the image light IG emitted from the light modulator 182, and is arranged at a position closer to the +D2 side than the light modulator 182 and overlapping with the light modulator 182 in the D1 direction and the D3 direction. The emission-side polarization element 176 contacts the light modulator 182 from the +D2 side, for example, but may also be arranged at an appropriate interval from the light modulator 182 in the D2 direction. The emission-side polarization element 176 is equivalent to a fifth polarization element, and emits a predetermined polarized light in the image light IG emitted from the light modulator 182 to the +D2 side along the D2 direction. The predetermined polarized light is equivalent to the fifth polarized light component, for example, P polarized light. The emission-side polarization element 176 is, for example, a reflective polarizer or an absorptive polarizer having a plate surface parallel to a surface including the D1 direction and the D3 direction. The emission-side polarization element 176 transmits a portion of the incident image light IG including the predetermined polarized light to the +D2 side, and reflects another portion of the image light IG to the -D2 side.

[0070] like Figure 1 As shown, the red light emitting section 103 is arranged at a position closer to the +D1 side than the green light emitting section 102, and is arranged in a region overlapping with the blue light emitting section 101 in the D2 direction and the D3 direction. The red light emitting section 103 emits red light LR. The red light LR emitted from the red light emitting section 103 travels toward the -D1 side along the D1 direction.

[0071] The red light emitting unit 103 includes a light source 123, a light guide element 143, and a parallelizing element 163. The light source 123 is supported by the substrate 113. The light source 123 is disposed on the substrate 113 on a plate surface on the -D1 side of a plate surface parallel to a surface including the D2 direction and the D3 direction. The light emitting surface of the light source 123 is arranged substantially parallel to the surface including the D2 direction and the D3 direction, and is a surface on the opposite side of the surface of the light source 123 in contact with the plate surface on the -D1 side of the substrate 113 in the D1 direction. The light source 123 is equivalent to a third light source, and emits red light LR in a red band in the visible band. The red band is, for example, a band of 610 nm to 700 nm.

[0072] The light source 123 is composed of, for example, an LED that emits red light LR. In addition, 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.

[0073] The substrate 113 is made of metal, for example, and also functions as a heat dissipation member that receives heat from the light source 123 that emits the red light LR and releases the heat to an external space.

[0074] The light guide element 143 is disposed on the optical path of the red light LR emitted from the light source 123, and is arranged at a position closer to the -D1 side than the light source 123 and overlapping with the light source 123 in the D2 direction and the D3 direction. The light guide element 143 is equivalent to a third light guide element, and has an incident end 143a on the +D1 side of the D1 direction, an emission end 143b on the -D1 side, and a side surface 143s and a reflection surface 143r extending between the incident end 143a and the emission end 143b in the D1 direction. The incident end 143a is equivalent to the third incident end, and extends parallel to the plane including the D2 direction and the D3 direction. 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, for example, a rectangle. The size of the incident end 143a in the plane including the D2 direction and the D3 direction may be equal to the size of the light emitting surface of the light source 123 in the plane including the D2 direction and the D3 direction, but is preferably moderately larger than the size of the light emitting surface of the light source 123 in the plane including the D2 direction and the D3 direction. The emission end 143b corresponds to the third emission end, extends parallel to the plane including the D2 direction and the D3 direction, and is larger than the incident end 143a. The shape of the emission end 143b when viewed from the D1 direction is the same as the modulation surface of the light modulator 183 when viewed from the same direction, for example, a rectangle. The size of the emission end 143b in the plane including the D2 direction and the D3 direction is equal to the size of the modulation surface of the light modulator 183 in the plane including the D2 direction and the D3 direction. The side surface 143s and the reflection surface 143r connect the peripheral edge of the incident end 143a and the peripheral edge of the emission end 143b in the D1 direction.

[0075] The red light LR emitted from the light source 123 enters the light guide element 143 from the incident end 143a. In the light guide element 143, the area surrounded by the incident end 143a, the emission end 143b and the reflection surface 143r is the area that propagates the red light LR. The size of the area surrounded by the incident end 143a, the emission end 143b and the reflection surface 143r in the plane including the D2 direction and the D3 direction increases as it moves from the +D1 side to the -D1 side of the D1 direction. In addition, as it moves from the +D1 side to the -D1 side, the shape of the area surrounded by the incident end 143a, the emission end 143b and the reflection surface 143r on the plane including the D2 direction and the D3 direction changes from the shape of the light emitting surface of the light source 123 when viewed from the D1 direction to the shape of the modulation surface of the light modulation element 183.

[0076] The side surface 143s of the light guide element 143 and the reflecting surface 143r provided on the side surface 143s as described later form a predetermined angle with respect to the imaginary line VX perpendicular to the incident end 143a and the optical axis, and move away from the imaginary line in a plane including the D2 direction and the D3 direction as moving from the +D1 side to the -D1 side. The red light LR incident on the light guide element 143 propagates from the +D1 side to the -D1 side in the area surrounded by the incident end 143a, the emission end 143b and the reflecting surface 143r.

[0077] When the shape of the modulation surface of the light modulator 183 when viewed along the D1 direction is a rectangle, the shape of the light emitting surface of the light source 123 when viewed along the D1 direction is also consistent with the rectangle. In this case, the side surface 143s including the short side of the rectangle and the reflection surface 143r with respect to the above-mentioned imaginary line and the optical axis preferably form a predetermined angle α in the range of 7° to 22°. The side surface 143s including the long side of the rectangle and the reflection surface 143r with respect to the above-mentioned imaginary line and the optical axis preferably form a predetermined angle β in the range of 14° to 36°.

[0078] A portion of the red light LR incident on the light guide element 143 forms an angle smaller than a predetermined angle with respect to the imaginary axis and the optical axis, and does not enter the reflection surface 143r once, but directly propagates from the incident end 143a to the emission end 143b. The remaining portion of the red light LR incident on the light guide element 143 forms an angle greater than a predetermined angle with respect to the imaginary axis and the optical axis, enters the reflection surface 143r from the incident end 143a more than once, and reaches the emission end 143b after being reflected by the reflection surface 143r. The path of the light of the red light LR in the area surrounded by the incident end 143a, the emission end 143b, and the reflection surface 143r varies depending on the incident angle to the incident end 143a, and involves a plurality of paths with different numbers of reflections at the reflection surface 143r. Thus, the illuminance distribution of the red light LR propagating in the area surrounded by the incident end 143a, the emission end 143b, and the reflection surface 143r is uniformized in the plane including the D2 direction and the D3 direction. That is, the light guide element 143 makes the illuminance distribution of the incident red light LR uniform in the plane including the D2 direction and the D3 direction. The red light LR with uniform illuminance distribution is emitted from the emission end 143b to the -D1 side.

[0079] The light guide element 143 is similar to the light guide elements 141 and 142, and is a hollow reflector formed by a plate-like member made of a transparent material such as optical glass. When viewed along the D1 direction, the end of the reflector frame on the +D1 side has the same shape and size as the incident end 143a and the light emitting surface of the light source 123, and is formed into a rectangular frame shape, for example. The end of the reflector frame on the -D1 side has the same shape and size as the emission end 143b and the modulation surface of the light modulation element 183, and is formed into a rectangular frame shape of a size different from that of the end on the +D1 side.

[0080] The reflector of the light guide element 143 is formed by connecting the sides of the four plate-like parts corresponding to the legs to each other. The length of the side parallel to the D2 direction or the D3 direction on the +D1 side corresponding to the upper base of the four plate-like parts is set according to the size of the incident end 143a and the light emitting surface of the light source 123 in the D2 direction or the D3 direction. The length of the side parallel to the D2 direction or the D3 direction on the -D1 side corresponding to the lower base of the four plate-like parts is set according to the size of the emission end 143b and the modulation surface of the light modulation element 183 in the D2 direction or the D3 direction.

[0081] In the reflector of the light guide element 143, in order to improve the reflectivity of the red light LR incident on the light guide element 143 from the incident end 143a near the side surface 143s, a reflective film 253 composed of a dielectric multilayer film or the like is also provided on the plate surface of the plate-like member constituting the reflector on the side opposite to the side surface 143s, that is, the plate surface of the plate-like member facing the internal space. A portion of the red light LR incident on the internal space of the reflector of the light guide element 143 from the incident end 143a is reflected by the reflective film 253 and travels to the -D1 side.

[0082] The intensity of the red light LR reflected by the reflective film 253 sometimes depends on the incident angle of the red light LR incident on the reflective film 253. In the case where the reflective film 253 is composed of a dielectric multilayer film, the incident angle dependence of the intensity of the red light LR emitted from the reflective film 253 changes, for example, depending on the parameters such as the refractive index of the multiple films included in the dielectric multilayer film, the thickness of the film, and the number of films. As described above, for example, when the angle α is in the range of 7° to 22° and the angle β is in the range of 14° to 36°, the reflective film 253 is designed in such a way that the incident angle of the red light LR with the highest intensity emitted from the reflecting surface 143r and the reflective film 253 is in the range of 60° to 90°, and the parameters of the dielectric multilayer film are appropriately determined. The relationship between the incident angle of the red light LR to the reflective film 253 and the intensity of the red light LR emitted from the reflective film 253 is also obtained by numerical simulation based on the structure of the red light emitting portion 103 and ray tracing.

[0083] The parallelizing element 163 is disposed on the optical path of the red light LR emitted from the light guide element 143, and is arranged at a position closer to the -D1 side than the light guide element 143 and overlapping with the light guide element 143 in the D2 direction and the D3 direction. The parallelizing element 163 is equivalent to a third parallelizing element, and parallelizes the red light LR emitted from the light guide element 143 along the D1 direction.

[0084] The parallelizing element 163 is, for example, a plano-convex lens, and has an incident surface composed of a flat surface perpendicular to the D1 direction and an exit surface composed 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 parallelizing element 163 is at least located on the +D1 side of the parallelizing element 163, and on the side opposite to the -D1 side from which the red light LR is emitted from the parallelizing element 163, and further located on the +D1 side of the light guide element 143. The incident surface of the parallelizing element 163 is in contact with the exit end 143b of the light guide element 143. By making the parallelizing element 163 contact with the exit end 143b, the red light LR emitted from the exit end 143b of the light guide element 143 is taken into the parallelizing element 163 to the maximum extent, and the loss of the red light LR can be suppressed. However, the parallelizing element 163 may be an optical lens other than a plano-convex lens capable of parallelizing the incident red light LR, and may be disposed at an appropriate interval from the light guiding element 143 in the D1 direction.

[0085] The focal length f3 of the parallelizing element 163 corresponds to the third focal length, and is longer than the length g3 from the incident end 143a to the emitting end 143b of the light guide element 143 in the direction D1. The length g3 corresponds to the third length.

[0086] Although not shown, similarly to the green light emitting section 102, in the red light emitting section 103, when the synthetic vector of a plurality of light rays included in the red light LR emitted from the emission end 143b to the -D1 side is extended to the +D1 side under the assumption that the effect of the parallelizing element 163 is ignored, the position intersecting the center line and the optical axis of the parallelizing element 163 and the light guide element 143 does not strictly converge to a single point, but is spread over a region of a small width in the D1 direction. As a result, the focus F3 of the plano-convex lens of the parallelizing element 163 slightly expands in the D1 direction, but constitutes a single point macroscopically.

[0087] Since the focal length f3 of the parallelizing element 163 is set to the +D1 side of the light guide element 143 and longer than the length g3 of the light guide element 143 according to the position of the focus F3 , the plurality of light beams included in the red light LR are efficiently parallelized with respect to the D1 direction.

[0088] Specifically, the focal length f3 of the parallelization element 163 is preferably greater than or equal to 1.1 times the length g3 of the light-guiding element 143. The focal length f3 is more preferably greater than or equal to 1.1 times the length g3 and less than or equal to 2.0 times the length g3. By setting the focal length f3 within the above range, the red light LR emitted from the light source 123 is efficiently parallelized, and the utilization efficiency of the red light LR is improved. The preferred range of the focal length f3 is also confirmed by numerical simulation based on the structure of the red light emitting portion 103 and ray tracing.

[0089] When the focal length f3 of the parallelizing element 163 is shorter than 1.1 times the length g3 of the light guide element 143, the illumination range of the red light LR emitted from the parallelizing element 163 is excessively reduced, and when the image light converted by the subsequent light modulating element 183 is projected and enlarged and displayed on the screen SC, a part of the original image may not be displayed. On the other hand, when the focal length f3 is longer than 2.0 times the length g3, a part of the red light LR emitted from the parallelizing element 163 will not be incident on the light modulating element 183 arranged at a later stage than the parallelizing element 163. As a result, the utilization efficiency of the red light LR may be reduced.

[0090] The incident-side polarizing element 173 is disposed on the optical path of the red light LR emitted from the parallelizing element 163, and is arranged at a position closer to the -D1 side than the parallelizing element 163 and overlapping with the parallelizing element 163 in the D2 direction and the D3 direction. The incident-side polarizing element 173 contacts the light modulating element 183 from the +D1 side, for example, but may also be arranged at an appropriate interval from the light modulating element 183 in the D1 direction.

[0091] The incident-side polarizing element 173 is equivalent to a third polarizing element, and causes the prescribed polarized light in the red light LR emitted from the parallelizing element 163 to be emitted toward the -D1 side along the D1 direction. The prescribed polarized light is equivalent to the third polarized light component, for example, S polarized light. The incident-side polarizing element 173 is, for example, a reflective polarizing plate having a plate surface parallel to a surface including the D2 direction and the D3 direction. The incident-side polarizing element 173 causes a portion of the incident red light LR including the prescribed polarized light to pass toward the -D1 side, and reflects another portion of the red light LR toward the +D1 side.

[0092] The red light LR emitted from the light source 123 includes at least P polarized light and S polarized light, for example, randomly polarized light. The P polarized light component in the red light LR emitted from the light source 123 passes through the light guide element 143 and the parallelization element 163 in sequence as described above, passes through the incident side polarization element 173, and is emitted to the -D1 side of the incident side polarization element 173. The S polarized light component in the red light LR is the same as the P polarized light component, passes through the light guide element 143 and the parallelization element 163 in sequence, but is reflected by the incident surface of the incident side polarization element 173, and is emitted to the +D1 side of the incident side polarization element 173.

[0093] The light modulator 183 is disposed on the optical path of the red light LR emitted from the incident-side polarizing element 173, and is arranged at a position closer to the -D1 side than the incident-side polarizing element 173 and overlapping with the incident-side polarizing element 173 in the D2 direction and the D3 direction. The light modulator 183 is equivalent to a third light modulator, and modulates the red light LR emitted from the incident-side polarizing element 173 based on image information sent from an image forming device such as a computer (not shown) externally connected to the light modulator 183.

[0094] The light modulator 183 is, for example, a transmissive liquid crystal panel. The liquid crystal panel constituting the light modulator 183 has a plurality of pixels not shown. Each pixel is provided with a switching element. The switching element is, for example, a TFT. An electrical signal corresponding to the brightness of the red light at the relative position of each pixel in the modulation surface of the light modulator 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 polarization element 173 by the action of the switching element corresponding to the above-mentioned electrical signal, thereby generating red image light IR. The image light IR is equivalent to the third light. The light modulator 183 emits the image light IR generated by the liquid crystal panel to the -D1 side along the D1 direction.

[0095] The emission-side polarization element 177 is provided on the optical path of the image light IR emitted from the light modulator 183, and is arranged at a position closer to the -D1 side than the light modulator 183 and overlapping with the light modulator 183 in the D2 direction and the D3 direction. The emission-side polarization element 177 contacts the light modulator 183 from the -D1 side, for example, but may also be arranged at an appropriate interval from the light modulator 183 in the D1 direction. The emission-side polarization element 177 is equivalent to the sixth polarization element, and emits the prescribed polarization light in the image light IR emitted from the light modulator 183 to the -D1 side along the D1 direction. The prescribed polarization light is equivalent to the sixth polarization light component, for example, P polarization light. The emission-side polarization element 177 is, for example, a reflective polarizer or an absorptive polarizer having a plate surface parallel to a surface including the D2 direction and the D3 direction. The emission-side polarization element 177 transmits a part of the incident image light IR including the prescribed polarization light to the -D1 side, and reflects the other part of the green light LG to the +D1 side.

[0096] The photosynthesizing element 200 is disposed in a region where the optical path of the blue image light IB emitted from the emission-side polarizing element 175, the optical path of the green image light IG emitted from the emission-side polarizing element 176, and the optical path of the red image light IR emitted from the emission-side polarizing element 177 intersect. The photosynthesizing element 200 synthesizes the image lights IB, IG, and IR emitted from the emission-side polarizing elements 175, 176, and 177, and emits the image lights to the +D2 side along the D2 direction.

[0097] The photosynthesizing element 200 is, for example, a cross dichroic prism 210. The cross dichroic prism 210 includes an incident surface 210c facing the exit surface of the exit-side polarizing element 175, an incident surface 210d facing the exit surface of the exit-side polarizing element 176, an incident surface 210e facing the exit surface of the exit-side polarizing element 177, an exit surface 210b, and two reflective films 211 and 212. The incident surfaces 210c and 210e are parallel to a plane including the D2 direction and the D3 direction, and overlap each other in the D2 direction and the D3 direction. The incident surface 210d and the exit surface 210b are parallel to a plane including the D1 direction and the D3 direction, and overlap each other in the D1 direction and the D3 direction.

[0098] When viewed along the D3 direction, the reflective film 211 is configured to move from the +D2 side to the -D2 side as it moves from the -D1 side to the +D1 side. When viewed along the D3 direction, the reflective film 212 is configured to move from the -D2 side to the +D2 side as it moves from the -D1 side to the +D1 side. The reflective films 211 and 212 overlap with the incident surfaces 210c and 210e in the D2 direction, and overlap with the emitting 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.

[0099] The cross dichroic prism 210 is constructed as follows: when viewed from the D3 direction, the four right-angle prisms align their right-angle vertices with the center position of the photosynthesizing element 200 so that the right-angled constituting surfaces are attached to each other. 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 arranged on the right-angled constituting surface of the four right-angle prisms, which moves from the +D2 side to the -D2 side as it moves from the -D1 side to the +D1 side as described above, and is composed of, for example, a dielectric multilayer film. The reflective film 212 is arranged on the right-angled constituting surface of the four right-angle prisms, which moves from the -D2 side to the +D2 side as it moves from the -D1 side to the +D1 side as described above.

[0100] The P-polarized light of the blue image light IB emitted from the emission-side polarizing element 175 enters the interior of the cross dichroic prism 210 from the incident surface 210c along the D1 direction toward the +D1 side, passes through the reflection film 211, is reflected by the reflection film 212, and travels toward the +D2 side. The P-polarized light of the green image light IG emitted from the emission-side polarizing element 176 enters the interior of the cross dichroic prism 210 from the incident surface 210d along the D2 direction toward the +D2 side, passes through the reflection films 211 and 212, and travels straight toward the +D2 side. The P-polarized light of the red image light IR emitted from the emission-side polarizing element 177 enters the interior of the cross dichroic prism 210 from the incident surface 210e along the D1 direction toward the -D1 side, passes through the reflection film 212, is reflected by the reflection film 211, and travels toward the +D2 side. The image lights IB, IG, and IR emitted toward the +D2 side from the reflection films 211 and 212 of the cross dichroic prism 210 are combined to generate full-color image light IM. The cross dichroic prism 210 emits full-color image light IM toward the +D2 side along the D2 direction from the emission surface 210b.

[0101] The projection optical system 250 is arranged on the optical path of the image light IM emitted from the photosynthesizing element 200. The projection optical system 250 projects the image light IM emitted from the projection optical system 250 onto the screen SC arranged on the +D2 side, and enlarges and displays the image sent from the image forming device to the light modulation elements 181, 182, and 183 on the screen SC.

[0102] The projection optical system 250 is composed of, for example, one or more optical lenses arranged along the D2 direction. The optical lenses include, for example, plano-convex lenses, plano-concave lenses, bi-convex lenses, bi-concave lenses, meniscus lenses, aspherical lenses, free-form surface lenses, and the like.

[0103] The projector 301 of the present embodiment described above includes a light source (first light source) 121, a light source (second light source) 122, a light source (third light source) 123, a light guide element (first light guide element) 141, a light guide element (second light guide element) 142, a light guide element (third light guide element) 143, a parallelizing element (first parallelizing element) 161, a parallelizing element (second parallelizing element) 162, a parallelizing element (third parallelizing element) 163, a light modulating element (first light modulating element) 181, a light modulating element (second light modulating element) 182, a light modulating element (third light modulating element) 183, a photosynthesizing element 200, and a projection optical system 250. The light source 121 emits blue light (first light) LB in a blue wavelength band (first wavelength band). The light source 122 emits green light (second light) LG in a green wavelength band (second wavelength band) different from the blue wavelength band. The light source 123 emits red light (third light) LR in a red wavelength band (third wavelength band) different from the blue wavelength band and the green wavelength band. The light guide element 141 has an incident end (first incident end) 141a for the blue light LB emitted from the light source 121 to be incident and an emission end (first emission end) 141b for emitting the blue light LB, so as to make the illuminance (in-plane illuminance) in a plane including the D2 direction and the D3 direction of the blue light LB uniform. The light guide element 142 has an incident end (second incident end) 142a for the green light LG emitted from the light source 122 to be incident and an emission end (second emission end) 142b for emitting the green light LG, so as to make the illuminance (in-plane illuminance) in a plane including the D1 direction and the D3 direction of the green light LG uniform. The light guide element 143 has an incident end (third incident end) 143a for the red light LR emitted from the light source 123 to be incident and an emission end (third emission end) 143b for emitting the red light LR, so as to make the illumination (in-plane illumination) of the red light LR in the plane including the D1 direction and the D3 direction uniform. The light modulator (first light modulator) 181 modulates the blue light LB emitted from the parallelization element 161 according to the image information. The light modulator (second light modulator) 182 modulates the green light LG emitted from the parallelization element 162 according to the image information. The light modulator (third light modulator) 183 modulates the red light LR emitted from the parallelization element 163 according to the image information. The light synthesizing element 200 synthesizes the image light (first light) IB emitted from the light modulator 181, the image light (second light) IG emitted from the light modulator 182, and the image light (third light) IR emitted from the light modulator 183 and emits them. The projection optical system 250 projects the image light (light) IM emitted from the photosynthesizing element 200. In the projector 301 of this embodiment, the focal length (first focal length) f1 of the parallelizing element 161 is longer than the length (first length) g1 in the D1 direction from the incident end 141a to the emission end 141b of the light guide element 141.The focal length (second focal length) f2 of the parallelizing element 162 is longer than the length (second length) g2 in the D2 direction from the incident end 142a to the emitting end 142b of the light guide element 142. The focal length (third focal length) f3 of the parallelizing element 163 is longer than the length (third length) g3 in the D1 direction from the incident end 143a to the emitting end 143b of the light guide element 143.

[0104] In the projector 301 of the present embodiment, three color lights, i.e., blue light LB, green light LG, and red light LR, emitted from the light sources 121, 122, and 123 are directly converted into image lights IB, IG, and IR by the light modulators 181, 182, and 183, and the image lights IB, IG, and IR are synthesized by the light synthesizer 200, and the generated full-color image light IM is projected. On the other hand, in conventional projectors, white light is generated, the white light is separated into three color lights by a color separation element or a color separation optical system, each color light is converted into image light by a light modulator, the image light is synthesized into full-color image light by a light synthesizer, and the full-color image light is projected. In the projector 301 of the present embodiment, a color synthesizer element and a color synthesizer optical system for synthesizing the three color lights into white light and a color separation element and a color separation optical system for separating the white light into three color lights are not required in the preceding stage of the light modulator element corresponding to the three color lights, so that the number of parts, the number of devices, and the size can be suppressed compared with conventional projectors. According to the projector 301 of this embodiment, it is possible to achieve miniaturization compared with conventional projectors.

[0105] In the projector 301 of this embodiment, the focal length f1 of the parallelization element 161 is longer than the length g1 of the light guiding element 141, the focal length f2 of the parallelization element 162 is longer than the length g2 of the light guiding element 142, and the focal length f3 of the parallelization element 163 is longer than the length g3 of the light guiding element 143. Therefore, the parallelism of the blue light LB, the green light LG and the red light LR emitted from the light guiding elements 141, 142 and 143 can be improved, so that these colored lights are efficiently incident on the parallelization elements 161, 162 and 163, thereby improving the utilization efficiency of the colored lights.

[0106] In the projector 301 of this embodiment, the cross-sectional shape of the light guide elements 141 and 143 perpendicular to the optical axis and the D1 direction is a rectangle, and the cross-sectional shape of the light guide element 142 perpendicular to the optical axis and the D2 direction is a rectangle.

[0107] In the projector 301 of this embodiment, rectangular blue light LB, green light LG, and red light LR with uniform illumination can be easily generated in a plane perpendicular to the optical axis of the colored light by the light guide elements 141, 142, and 143. According to the projector 301 of this embodiment, colored light consistent with the rectangular modulation surface of the light modulator elements 181, 182, and 183 can be easily generated.

[0108] The projector 301 of this embodiment further includes an incident-side polarization element (first polarization element) 171, an incident-side polarization element (second polarization element) 172, and an incident-side polarization element (third polarization element) 173. The incident-side polarization element 171 is disposed between the parallelization element 161 and the light modulator 181, and transmits a portion of the blue light LB having the S polarization component (first polarization component) and reflects the other portion of the blue light LB, namely the P polarization component. In the projector 301 of this embodiment, the incident-side polarization element 172 is disposed between the parallelization element 162 and the light modulator 182, and transmits a portion of the green light LG having the S polarization component (second polarization component) and reflects the other portion of the green light LG, namely the P polarization component. The incident-side polarization element 173 is disposed between the parallelization element 163 and the light modulator 183, and transmits a portion of the red light LR having the S polarization component (third polarization component) and reflects the other portion of the red light LR, namely the P polarization component. In projector 301 of this embodiment, another part of blue light LB enters light guide element 141 and travels toward light source 121. Another part of green light LG enters light guide element 142 and travels toward light source 122. Another part of red light LR enters light guide element 143 and travels toward light source 123.

[0109] In the projector 301 of the present embodiment, another part of each of the blue light LB, green light LG, and red light LR reflected by the incident-side polarization elements 171, 172, 173 and emitted from the incident-side polarization elements 171, 172, 173 can be incident on the light sources 121, 122, 123. In the case where, for example, the light source 122 has a fluorescent body 124 among the light sources 121, 122, 123, another part of the green light LG directed toward the light source 122 is incident on the fluorescent body 124, and contributes to the excitation of the fluorescent body 124. In addition, in the case where the substrates 111, 112, 113 of the light sources 121, 122, 123 have reflectivity, another part of each of the blue light LB, green light LG, and red light LR directed toward the light sources 121, 122, 123 is reflected by the substrates 111, 112, 113, and is incident on the light guide elements 141, 142, 143 again to be used. According to the projector 301 of this embodiment, another part of the blue light LB, green light LG and red light LR reflected by the incident side polarization elements 171, 172, 173 is again incident on the light guiding elements 141, 142, 143, thereby improving the utilization efficiency of the blue light LB, green light LG and red light LR.

[0110] In the projector 301 of the present embodiment, the cross-sectional area of ​​the emission end 141b of the light guide element 141 including the D2 direction and the D3 direction is larger than the cross-sectional area of ​​the incident end 141a of the light guide element 141. The cross-sectional area of ​​the emission end 142b of the light guide element 142 including the D1 direction and the D3 direction is larger than the cross-sectional area of ​​the incident end 142a of the light guide element 142. The cross-sectional area of ​​the emission end 143b of the light guide element 143 including the D2 direction and the D3 direction is larger than the cross-sectional area of ​​the incident end 143a of the light guide element 143 including the D2 direction and the D3 direction.

[0111] Figure 4 1 is a schematic diagram of the green light emitting unit 102, the incident-side polarizing element 172, and the light modulating element 182 as an example. Figure 3 and Figure 4 In the embodiment, as a modified example of the projector 301 of the present embodiment, in the direction D2, the incident-side polarization element 172 is arranged at a distance from the parallelization element 162, and the light modulation element 182 is arranged at a distance from the incident-side polarization element 172. Figure 4As shown, as described above, for example, the width w142A of the incident end 142a of the light guide element 142 in the D1 direction is set according to the width w122 of the light emitting surface 122a of the light source 122 in the D1 direction. The width w142B of the emitting end 142b of the light guide element 142 in the D1 direction is greater than the width w142A of the incident end 142a. Although not shown in the figure, the width and cross-sectional area of ​​the emitting end 142b of the light guide element 142 in the D2 direction are greater than the width and cross-sectional area of ​​the incident end 142a in the D2 direction.

[0112] In the projector 301 of the present embodiment, the illumination distribution of the blue light LB, the green light LG, and the red light LR is uniformized before entering from the incident ends 141a, 142a, 143a of the light guide elements 141, 142, 143 and emitting from the emission ends 141b, 142b, 143b, and the irradiation area of ​​each color light is expanded. According to the projector 301 of the present embodiment, the size of the blue light LB, the green light LG, and the red light LR emitted from the light sources 121, 122, 123 having a smaller light emitting surface than the modulation surface of the light modulators 181, 182, 183 on the plane perpendicular to the optical axis, that is, the irradiation area can be easily expanded in accordance with the modulation surface of each light modulator 181, 182, 183.

[0113] In the projector 301 of the present embodiment, the length from the incident end 141a to the emission end 141b of the light guide element 141 is greater than 8 mm and less than 25 mm. The length from the incident end 142a to the emission end of the light guide element 142 is greater than 8 mm and less than 25 mm. The length from the incident end 143a to the emission end 143b of the light guide element 143 is greater than 8 mm and less than 25 mm.

[0114] According to the projector 301 of this embodiment, the extraction efficiency of the light guide elements 141 , 142 , 143 for the blue light LB, green light LG, and red light LR can be improved, and the illuminance distribution of the blue light LB, green light LG, and red light LR can be made uniform.

[0115] In the projector 301 of the present embodiment, regarding the length g1 of the light guide element 141 and the focal length f1 of the parallelization element 161, 1.1×g1≤f1≤2.0×g1. Regarding the length g2 of the light guide element 142 and the focal length f2 of the parallelization element 162, 1.1×g2≤f2≤2.0×g2. Regarding the length g3 of the light guide element 143 and the focal length f3 of the parallelization element 163, 1.1×g3≤f3≤2.0×g3.

[0116] According to the projector 301 of this embodiment, the blue light LB, green light LG and red light LR emitted from the light guide elements 141, 142, 143 can be more efficiently incident on the parallelization elements 161, 162, 163, thereby improving the utilization efficiency of the blue light LB, green light LG and red light LR.

[0117] In the projector 301 of the present embodiment, the focus F1 of the parallelizing element 161 is located on the -D1 side of the light source 121, that is, on the side opposite to the emission side of the blue light LB of the light source 121. The focus F2 of the parallelizing element 162 is located on the -D2 side of the light source 122, that is, on the side opposite to the emission side of the green light LG of the light source 122. The focus F3 of the parallelizing element 163 is located on the +D1 side of the light source 123, that is, on the side opposite to the emission side of the red light LR of the light source 123.

[0118] According to the projector 301 of this embodiment, the blue light LB, green light LG and red light LR emitted from the light guide elements 141, 142, 143 can be efficiently incident on the parallelization elements 161, 162, 163, thereby improving the utilization efficiency of the blue light LB, green light LG and red light LR.

[0119] In the projector 301 of the present embodiment, when the length g1 of the light guide element 141 is set to 1, the distance between the position of the focus F1 of the parallelization element 161 in the D1 direction and the light emitting surface of the light source 121 emitting blue light LB is greater than 0.1 and less than 0.5. When the length g2 of the light guide element 142 is set to 1, the distance between the position of the focus F2 of the parallelization element 162 in the D2 direction and the light emitting surface (light emitting surface) 122a emitting green light LG from the light source 122 is greater than 0.1 and less than 0.5. Figure 2 When the length g3 of the light guide element 143 is set to 1, the distance between the position of the focus F3 of the parallelizing element 163 and the light emitting surface of the light source 123 emitting the red light LR in the direction D1 is greater than or equal to 0.1 and less than or equal to 0.5.

[0120] According to the projector 301 of this embodiment, the blue light LB, green light LG, and red light LR that are not blocked by the parallelizing elements 161 , 162 , and 163 and are taken in can be reduced, thereby improving the utilization efficiency of the blue light LB, green light LG, and red light LR.

[0121] In the projector 301 of the present embodiment, the light guide elements 141 , 142 , and 143 are made of glass such as optical glass or metallic glass.

[0122] In the projector 301 of this embodiment, as described above, the light guide elements 141, 142, 143 are formed of a plate-like member made of a transparent material including glass such as optical glass. According to the projector 301 of this embodiment, the heat dissipation and heat resistance of the light guide elements 141, 142, 143 can be improved.

[0123] In addition, as a modification of the projector 301 of the present embodiment, the plate-like components constituting the light guide elements 141, 142, and 143 may also be made of metal. That is, the reflectors of the light guide elements 141, 142, and 143 may also be made of a plate-like component, which is made of a reflective material such as a metal material that reflects the blue light LB, the green light LG, and the red light LR. In this case, as in the case where a reflective film is provided on the plate surface of the plate-like component made of a transparent material that faces the internal space, the plate surface of the plate-like component that faces the internal space of the reflector functions as the reflective surface 141r, 142r, and 143r. A portion of the blue light LB, the green light LG, and the red light LR that enter the internal space of the reflector of the light guide elements 141, 142, and 143 from the incident ends 141a, 142a, and 143a is reflected by the plate surface of the plate-like component that faces the internal space of the reflector and travels along the optical axis. In the modification of the projector 301 of the present embodiment, the heat dissipation and heat resistance of the light guide elements 141 , 142 , and 143 can also be improved.

[0124] In the projector 301 of the present embodiment, the light guide elements 141 , 142 , 143 are hollow, and reflective films 251 , 252 , 253 are provided on the surfaces (inner surfaces) of the plate-like members constituting the light guide elements 141 , 142 , 143 that face the internal space.

[0125] In the projector 301 of the present embodiment, a portion of each of the blue light LB, green light LG, and red light LR incident on the light guide elements 141, 142, and 143 is specularly reflected by the reflective films 251, 252, and 253, and propagates in the internal space of the light guide elements 141, 142, and 143. According to the projector 301 of the present embodiment, the loss of the blue light LB, green light LG, and red light LR inside the light guide elements 141, 142, and 143 can be reduced.

[0126] In addition, as another variation of the projector 301 of the present embodiment, the light guide elements 141, 142, 143 may also be solid and made of a transparent material such as optical glass. In this case, the plate surfaces, i.e., the side surfaces 141s, 142s, 143s, of the reflectors of the light guide elements 141, 142, 143 that face the external space function as the reflection surfaces 141r, 142r, 143r. A portion of the blue light LB, the green light LG, and the red light LR that enter the reflectors of the light guide elements 141, 142, 143 from the incident ends 141a, 142a, 143a are totally reflected by the reflection surfaces 141r, 142r, 143r of the reflectors that face the external space, and travel along the optical axis. In addition, the light guide elements 141, 142, 143 may be solid and made of transparent materials such as optical glass, and reflective films 251, 252, 253 may be provided on the side surfaces 141s, 142s, 143s. In other variations of the projector 301 of the present embodiment, the loss of the blue light LB, the green light LG, and the red light LR inside the light guide elements 141, 142, 143 may also be reduced.

[0127] In the projector 301 of the present embodiment, when the parallelizing element 161 is observed along the optical axis, that is, when the parallelizing element 161 is observed along the D1 direction, the parallelizing element 161 covers the emission end 141b of the light guide element 141 from the +D1 side. When the parallelizing element 162 is observed along the optical axis, that is, when the parallelizing element 162 is observed along the D2 direction, the parallelizing element 162 covers the emission end 142b of the light guide element 142 from the +D2 side. When the parallelizing element 163 is observed along the optical axis, that is, when the parallelizing element 163 is observed along the D1 direction, the parallelizing element 163 covers the emission end 143b of the light guide element 143 from the -D1 side.

[0128] According to the projector 301 of this embodiment, the blue light LB, green light LG and red light LR emitted from the emission ends 141b, 142b, 143b of the light guiding elements 141, 142, 143 but not blocked and taken in by the parallelization elements 161, 162, 163 can be reduced, and the utilization efficiency of the blue light LB, green light LG and red light LR can be improved.

[0129] As another variation of the projector 301 of the present embodiment, the light guiding elements 141, 142, and 143 may be hollow, at least a portion of the parallelization element 161 may be housed in the light guiding element 141, at least a portion of the parallelization element 162 may be housed in the light guiding element 142, and at least a portion of the parallelization element 163 may be housed in the light guiding element 143.

[0130] In the above-mentioned variation example of the projector 301 of the present embodiment, the parallelization elements 161, 162, and 163 may also be composed of a plano-convex lens having a flat surface and a convex surface protruding toward the incident side of the blue light LB, the green light LG, and the red light LR, or a double convex lens having convex surfaces protruding toward the incident side and the emitting side of the blue light LB, the green light LG, and the red light LR.

[0131] Figure 5 and Figure 6 FIG. 1 is a schematic diagram of the green light emitting unit 102 in another modified example of the projector 301 of the present embodiment. Figure 5 In the illustrated modification, a light guide element 146 is provided in place of the light guide element 142. The light guide element 146 is solid and formed of a transparent material. Figure 5 In the modified example shown, the emission end 142b of the light guide element 146 is formed of a convex surface that protrudes toward the -D2 side, that is, the incident side of the green light LG. Figure 5 In the variation shown, a parallelizing element 166 is provided instead of the parallelizing element 162. The parallelizing element 166 is a plano-convex lens having: an incident surface 166a which is composed of a convex curved surface protruding toward the -D2 side, i.e., the incident side of the green light LG; and an exit surface 166b which is parallel to the plane including the D1 direction and the D3 direction. The incident surface 166a of the parallelizing element 166 is in contact with the exit end 146b on the opposite side of the incident end 146a of the light-guiding element 146 in the D2 direction, and is substantially configured in the same manner as in the state in which a portion of the incident side of the green light LG in the parallelizing element 166 is housed in the light-guiding element 146. According to Figure 5 The modified example shown can efficiently take the green light LG emitted from the emission end 146b of the light guide element 146 into the parallelizing element 166, minimize the green light LG that is not blocked by the parallelizing element 166 and taken in, and improve the utilization efficiency of the green light LG. Figure 5 The illustrated structure can be applied to the blue light emitting section 101 and the red light emitting section 103 of the projector 301 of the present embodiment.

[0132] exist Figure 6 In the illustrated modification, the light guide element 142 is hollow, and a parallelizing element 166 is provided instead of the parallelizing element 162. A portion of the incident side of the green light LG in the parallelizing element 166 is accommodated in the internal space of the light guide element 142. Figure 6 The modified example shown can efficiently take the green light LG emitted from the emission end 142b of the light guide element 142 on the -D2 side into the parallelization element 166, minimize the green light LG that is not blocked by the parallelization element 166 and taken in, and improve the utilization efficiency of the green light LG. Figure 6The illustrated structure can also be applied to the blue light emitting section 101 and the red light emitting section 103 of the projector 301 of the present embodiment.

[0133] As another modification of the projector 301 of this embodiment, the incident side polarization element (first polarization element) of the blue light emitting section 101 may be fixed to the parallelization element 161. The incident side polarization element (second polarization element) of the green light emitting section 102 may be fixed to the parallelization element 162. The incident side polarization element (third polarization element) of the red light emitting section 103 may be fixed to the parallelization element 163.

[0134] Figure 7 and Figure 8 FIG. 1 is a schematic diagram of the green light emitting unit 102 in the above-mentioned modification of the projector 301 according to the present embodiment. Figure 7 In the modified example shown, an incident-side polarizing element (second polarizing element) 272 is provided instead of the incident-side polarizing element 172. The incident-side polarizing element 272 is a reflective polarizing layer or a polarizing film having the same effect as the incident-side polarizing element 172. The incident-side polarizing element 272 is fixed to the parallelizing element 162 by being formed on the emission surface 162b of the parallelizing element 162. Figure 7 In the modified example shown, the space between the parallelizing element 162 and the incident-side polarizing element 272 can be removed, and the size increase of the green light emitting unit 102 and the projector 301 can be suppressed. Figure 7 In the modified example shown, no interface is generated between the air outside the parallelizing element 162 and the incident-side polarizing element 272 , and therefore, the loss of the green light LG can be reduced as much as possible, thereby improving the utilization efficiency of the green light LG. Figure 7 The illustrated structure can also be applied to the blue light emitting section 101 and the red light emitting section 103 of the projector 301 of the present embodiment.

[0135] exist Figure 8 In the variation shown, Figure 5 In the structure shown in FIG. 1 , an incident-side polarizing element 272 is provided. The incident-side polarizing element 272 is fixed to the parallelizing element 166 by being formed on the flat emission surface 166 b of the parallelizing element 166 . Figure 8 In the modified example shown, the space between the parallelizing element 166 and the incident-side polarizing element 272 can be eliminated, and the size increase of the green light emitting unit 102 and the projector 301 can be suppressed. Figure 7 In the modified example shown, no interface is generated between the air outside the parallelizing element 166 and the incident-side polarizing element 272 , and therefore, the loss of the green light LG can be reduced as much as possible, thereby improving the utilization efficiency of the green light LG. Figure 8The illustrated structure can also be applied to the blue light emitting section 101 and the red light emitting section 103 of the projector 301 of the present embodiment.

[0136] Fig. 9 It is a schematic diagram of the light source 122 and the light guide element 142 of the green light emitting unit 102. In the projector 301 of the present embodiment, the cross-sectional shape of the light guide elements 141, 142, 143 is a rectangle. When the inclination angle of the side surface including the short side of the light guide elements 141, 142, 143, that is, the angle relative to the optical axis is α, 7°≤α≤22°. When the inclination angle of the side surface including the long side of the light guide elements 141, 142, 143 is β, 14°≤β≤36°. Reflective films 251, 252, 253 are provided on the surface (inner surface) of the plate-like parts of the hollow light guide elements 141, 142, 143 that face the internal space. As Fig. 9 As shown in the example, when the reflectivity of the blue light LB, the green light LG, and the red light LR of the reflective films 251, 252, and 253 is the highest, the incident angle of the light incident on the reflective films 251, 252, and 253 is θ in When 60°≤θ in ≤90°.

[0137] In the projector 301 of the present embodiment, the light emitted from the light sources 121, 122, 123 is incident radially from the incident ends 141a, 142a, 143a at a predetermined angle relative to the optical axis into the light guide elements 141, 142, 143. By designing the reflective films 251, 252, 253 as described above, the intensity of the blue light LB, green light LG, and red light LR reflected by the reflective films 251, 252, 253 is high. According to the projector 301 of the present embodiment, the loss of the blue light LB, green light LG, and red light LR in the light guide elements 141, 142, 143 can be minimized, and the utilization efficiency of the blue light LB, green light LG, and red light LR can be improved.

[0138] The projector 301 of this embodiment further includes an output-side polarization element (fourth polarization element) 175, an output-side polarization element (fifth polarization element) 176, and an output-side polarization element (sixth polarization element) 177. The output-side polarization element 175 is disposed between the light modulator 181 and the photosynthesizing element 200, and transmits a portion of the image light (light) IB output from the light modulator 181 that has a P-polarized light component (fourth polarized light component), and absorbs the other portion of the image light IB except the P-polarized light component. The output-side polarization element 176 is disposed between the light modulator 182 and the photosynthesizing element 200, and transmits a portion of the image light (light) IG output from the light modulator 182 that has a P-polarized light component (fifth polarized light component), and absorbs the other portion of the image light IG except the P-polarized light component. The emission-side polarization element 177 is arranged between the light modulator 183 and the photosynthetic element 200, and transmits a portion of the image light (light) IR emitted from the light modulator having the P polarized light component (sixth polarized light component), and absorbs another portion of the image light IR except the P polarized light component.

[0139] In the projector 301 of the present embodiment, the P-polarized light component in the image lights IB, IG, IR is made incident on the photosynthetic element 200 through the output side polarization elements 175, 176, 177, for example, which are composed of an absorption-type polarizer or polarization element, and the other part of the image lights IB, IG, IR except the P-polarized light component is absorbed, thereby suppressing the return light and stray light to the light modulating elements 181, 182, 183 caused by the other part of the image lights IB, IG, IR.

[0140] As mentioned above, although the preferred embodiment of the present invention is described in detail, the present invention is not limited to this specific embodiment, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

[0141] In the blue light emitting section 101 or the red light emitting section 103, for example, the LEDs constituting the light sources 121 and 123 may have phosphors that are excited by light from the LED body and emit blue light LB and red light LR, as in the green light emitting section 102. In addition, the LED of the light source 122 of the green light emitting section 102 may not have the phosphor 124, and the light source 122 may be composed of an LED that directly emits green light LG. In addition, the polarized light components transmitted by the incident side polarizers arranged in the optical paths of the respective colored lights may be common components or may not be common components.

[0142] [Summary of the present disclosure]

[0143] The following is a summary of the present disclosure.

[0144] (Note 1)

[0145] A projector, comprising: a first light source, which emits a first light of a first wavelength band; a second light source, which emits a second light of a second wavelength band different from the first wavelength band; a third light source, which emits a third light of a third wavelength band different from the first wavelength band and the second wavelength band; a first light guide element, which has a first incident end for the first light emitted from the first light source to be incident and a first exit end for emitting the first light, so as to make the in-plane illumination of the first light uniform; a second light guide element, which has a second incident end for the second light emitted from the second light source to be incident and a second exit end for emitting the second light, so as to make the in-plane illumination of the second light uniform; a third light guide element, which has a third incident end for the third light emitted from the third light source to be incident and a third exit end for emitting the third light, so as to make the in-plane illumination of the third light uniform; a first parallelizing element, which parallelizes the first light emitted from the first light guide element; a second parallelizing element, which parallelizes the second light emitted from the second light guide element; a third parallelizing element, It parallelizes the third light emitted from the third light-guiding element; a first light modulating element, which modulates the first light emitted from the first parallelizing element based on image information; a second light modulating element, which modulates the second light emitted from the second parallelizing element based on image information; a third light modulating element, which modulates the third light emitted from the third parallelizing element based on image information; a photosynthetic element, which synthesizes the first light emitted from the first light modulating element, the second light emitted from the second light modulating element and the third light emitted from the third light modulating element and emits them; and a projection optical system, which projects the light emitted from the photosynthetic element, the first focal length of the first parallelizing element is longer than the first length from the first incident end to the first emission end, the second focal length of the second parallelizing element is longer than the second length from the second incident end to the second emission end, and the third focal length of the third parallelizing element is longer than the third length from the third incident end to the third emission end.

[0146] According to the structure of Supplementary Note 1, optical components for generating white light and optical components for separating light for each color light are unnecessary, so the number of components is small, and the enlargement of the three-panel projector can be suppressed, thereby realizing a compact projector.

[0147] (Supplementary Note 2) The projector according to Supplementary Note 1, wherein the cross-sectional shape of the first light guide element is a rectangle, the cross-sectional shape of the second light guide element is a rectangle, and the cross-sectional shape of the third light guide element is a rectangle.

[0148] According to the configuration of Supplementary Note 2, it is possible to easily generate rectangular illumination light with uniform illuminance distribution.

[0149] (Supplementary Note 3) A projector according to Supplementary Note 1 or 2, wherein the projector comprises: a first polarizing element, which is arranged between the first parallelizing element and the first light modulating element, so that a part of the first light having the first polarized light component is transmitted therethrough, and another part is reflected therethrough; a second polarizing element, which is arranged between the second parallelizing element and the second light modulating element, so that a part of the second light having the second polarized light component is transmitted therethrough, and another part is reflected therethrough; and a third polarizing element, which is arranged between the third parallelizing element and the third light modulating element, so that a part of the third light having the third polarized light component is transmitted therethrough, and another part is reflected therethrough, and another part of the first light is incident on the first light guiding element, another part of the second light is incident on the second light guiding element, and another part of the third light is incident on the third light guiding element.

[0150] According to the structure of Note 3, the first light, second light and third light reflected by the first polarization element, the second polarization element and the third polarization element can be incident on the first light guide element, the second light guide element and the third light guide element again, thereby improving the utilization efficiency of the first light, the second light and the third light.

[0151] (Note 4) A projector according to any one of Notes 1 to 3, wherein the cross-sectional area of ​​the first emission end is larger than the cross-sectional area of ​​the first incident end, the cross-sectional area of ​​the second emission end is larger than the cross-sectional area of ​​the second incident end, and the cross-sectional area of ​​the third emission end is larger than the cross-sectional area of ​​the third incident end.

[0152] According to the structure of Note 4, the size of the irradiation area of ​​the first light, the second light and the third light emitted from the first light source, the second light source and the third light source can be made consistent with the size of the modulation surface of the first light modulator, the second light modulator and the third light modulator, and the illumination distribution of the first light, the second light and the third light can be uniformly expanded.

[0153] (Note 5) A projector according to any one of Notes 1 to 4, wherein a first length from the first incident end to the first emission end is greater than 8 mm and less than 25 mm, a second length from the second incident end to the second emission end is greater than 8 mm and less than 25 mm, and a third length from the third incident end to the third emission end is greater than 8 mm and less than 25 mm.

[0154] According to the configuration of Supplementary Note 5, the extraction efficiency of the first light, the second light, and the third light can be improved, and the first light, the second light, and the third light can be well uniformed.

[0155] (Note 6) A projector according to any one of Notes 1 to 5, wherein, when the first length is g1 and the first focal length is f1, 1.1×g1≤f1≤2.0×g1, when the second length is g2 and the second focal length is f2, 1.1×g2≤f2≤2.0×g2, and when the third length is g3 and the third focal length is f3, 1.1×g3≤f3≤2.0×g3.

[0156] In the structure of Note 6, the first light, the second light and the third light emitted from the first light guiding element, the second light guiding element and the third light guiding element can be efficiently incident on the first parallelization element, the second parallelization element and the third parallelization element, thereby improving the utilization efficiency of the first light, the second light and the third light and realizing the miniaturization of the projector.

[0157] (Note 7) A projector according to any one of Notes 1 to 6, wherein the focus of the first parallelization element is located on the side of the first light source opposite to the emission side of the first light, the focus of the second parallelization element is located on the side of the second light source opposite to the emission side of the second light, and the focus of the third parallelization element is located on the side of the third light source opposite to the emission side of the third light.

[0158] In the structure of Note 7, the focal lengths of the first parallelizing element, the second parallelizing element, and the third parallelizing element can be appropriately arranged on the incident side of light, thereby improving the utilization efficiency of the first light, the second light, and the third light and achieving miniaturization of the projector.

[0159] (Note 8) A projector according to any one of Notes 1 to 7, wherein, when the first length is set to 1, the distance between the position of the focus of the first parallelization element and the light emitting surface of the first light source emitting the first light is greater than 0.1 and less than 0.5.

[0160] In the structure of Supplementary Note 8, the utilization efficiency of the first light, the second light, and the third light can be improved, and the projector can be miniaturized.

[0161] (Supplementary Note 9) The projector according to any one of Supplementary Notes 1 to 8, wherein the first light guide element, the second light guide element, and the third light guide element are made of glass or metal.

[0162] In the structure of Supplementary Note 9, the heat dissipation and heat resistance of the first light guide element, the second light guide element, and the third light guide element can be improved.

[0163] (Supplement 10) A projector according to any one of Supplements 1 to 9, wherein the first light guide element, the second light guide element and the third light guide element are hollow, and a reflective film is provided on the inner side surfaces of the first light guide element, the second light guide element and the third light guide element.

[0164] In the structure of Supplementary Note 10, the loss of the first light, the second light, and the third light generated in the first light guide element, the second light guide element, and the third light guide element can be suppressed, thereby improving the utilization efficiency of the first light, the second light, and the third light.

[0165] (Note 11) A projector according to any one of Notes 1 to 10, wherein, when observed along the optical axis of the first parallelization element, the first parallelization element covers the first emission end, when observed along the optical axis of the second parallelization element, the second parallelization element covers the second emission end, and when observed along the optical axis of the third parallelization element, the third parallelization element covers the third emission end.

[0166] In the structure of Supplementary Note 11, the amount of the first light, the second light, and the third light that are not blocked by the first parallelizing element, the second parallelizing element, and the third parallelizing element and are taken in can be suppressed, thereby improving the utilization efficiency of the first light, the second light, and the third light.

[0167] (Note 12) A projector according to any one of Notes 1 to 11, wherein the first light guiding element, the second light guiding element and the third light guiding element are hollow, at least a portion of the first parallelization element is housed in the first light guiding element, at least a portion of the second parallelization element is housed in the second light guiding element, and at least a portion of the third parallelization element is housed in the third light guiding element.

[0168] In the structure of Supplement 12, the amount of the first light, the second light, and the third light that are not blocked by the first parallelization element, the second parallelization element, and the third parallelization element and are taken in can be suppressed, thereby improving the utilization efficiency of the first light, the second light, and the third light. In addition, in the structure of Supplement 12, the spacing between the first light-guiding element, the second light-guiding element, and the third light-guiding element and the first parallelization element, the second parallelization element, and the third parallelization element in the direction along the optical axis of the first light, the second light, and the third light can be suppressed, thereby suppressing the enlargement of the projector.

[0169] (Supplementary Note 13) The projector according to Supplementary Note 3, wherein the first polarization element is fixed to the first parallelizing element, the second polarization element is fixed to the second parallelizing element, and the third polarization element is fixed to the third parallelizing element.

[0170] In the structure of Note 13, the spacing between the first parallelization element, the second parallelization element, and the third parallelization element and the first polarization element, the second polarization element, and the third polarization element can be suppressed, the loss of the first light, the second light, and the third light can be suppressed to improve the utilization efficiency of the first light, the second light, and the third light, and the size of the projector can be suppressed.

[0171] (Supplementary Note 14) The projector according to Supplementary Note 5, wherein the cross-sectional shape of the first light guide element is a rectangle, the cross-sectional shape of the second light guide element is a rectangle, and the cross-sectional shape of the third light guide element is a rectangle, and when the inclination angle of the side surfaces including the short sides of the first light guide element, the second light guide element, and the third light guide element is α, 7°≤α≤22°, and when the inclination angle of the side surfaces including the long sides of the first light guide element, the second light guide element, and the third light guide element is β, 14°≤β≤36°, and a reflective film is provided on the inner side surfaces of the first light guide element, the second light guide element, and the third light guide element, and when the reflectivity of the reflective film is the highest, the incident angle of light incident on the reflective film is θ in When 60°≤θ in ≤90°.

[0172] In the structure of Note 14, the loss of the first light, the second light, and the third light reflected in the first light guide element, the second light guide element, and the third light guide element and emitted from the first emission end, the second emission end, and the third emission end can be suppressed, thereby improving the utilization efficiency of the first light, the second light, and the third light.

[0173] (Note 15) A projector according to Note 3, wherein the projector comprises: a fourth polarization element, which is arranged between the first light modulator and the photosynthetic element, and allows a part of the light emitted from the first light modulator to pass through with the fourth polarization component, and absorbs another part; a fifth polarization element, which is arranged between the second light modulator and the photosynthetic element, and allows a part of the light emitted from the second light modulator to pass through with the fifth polarization component, and absorbs another part; and a sixth polarization element, which is arranged between the third light modulator and the photosynthetic element, and allows a part of the light emitted from the third light modulator to pass through with the sixth polarization component, and absorbs another part.

[0174] In the structure of Note 15, a part of the light emitted from the first light modulator, the second light modulator and the third light modulator having the fourth polarization component, the fifth polarization component and the sixth polarization component can be made incident on the photosynthetic element, and the other part of the light emitted from the first light modulator, the second light modulator and the third light modulator other than the fourth polarization component, the fifth polarization component and the sixth polarization component can be absorbed by the fourth polarization element, the fifth polarization element and the sixth polarization element, thereby suppressing the return light and stray light to the first light modulator, the second light modulator and the third light modulator caused by the other part other than the fourth polarization component, the fifth polarization component and the sixth polarization component.

Claims

1. A projector, comprising: A first light source emitting a first light of a first wavelength band; A second light source emitting second light of a second wavelength band different from the first wavelength band; A third light source emitting third light of a third wavelength band different from the first wavelength band and the second wavelength band; a first light guide element having a first incident end for the first light emitted from the first light source to be incident and a first emitting end for emitting the first light, so as to make the in-plane illumination of the first light uniform; a second light guide element having a second incident end for the second light emitted from the second light source to be incident and a second emitting end for emitting the second light, so as to make the in-plane illumination of the second light uniform; a third light guide element having a third incident end for the third light emitted from the third light source to be incident and a third emission end for emitting the third light, so as to make the in-plane illumination of the third light uniform; a first parallelizing element for parallelizing the first light emitted from the first light guiding element; a second parallelizing element for parallelizing the second light emitted from the second light guiding element; a third parallelizing element, which parallelizes the third light emitted from the third light guiding element; a first light modulation element that modulates the first light emitted from the first parallelization element based on image information; a second light modulation element that modulates the second light emitted from the second parallelization element based on image information; a third light modulation element that modulates the third light emitted from the third parallelization element based on image information; a light synthesizing element that synthesizes the first light emitted from the first light modulating element, the second light emitted from the second light modulating element, and the third light emitted from the third light modulating element, and emits the synthesized light; as well as a projection optical system that projects the light emitted from the photosynthetic element, A first focal length of the first parallelizing element is longer than a first length from the first incident end to the first emission end, A second focal length of the second parallelizing element is longer than a second length from the second incident end to the second emitting end, A third focal length of the third parallelizing element is longer than a third length from the third incident end to the third emitting end.

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

3. The projector according to claim 1 or 2, wherein: The projector has: A first polarizing element, which is disposed between the first parallelizing element and the first light modulating element, transmits a portion of the first light having a first polarized light component and reflects another portion; a second polarizing element disposed between the second parallelizing element and the second light modulating element, transmitting a portion of the second light having the second polarized light component and reflecting another portion; as well as a third polarizing element disposed between the third parallelizing element and the third light modulating element, transmitting a portion of the third light having a third polarized light component and reflecting another portion; Another part of the first light is incident on the first light guide element, Another part of the second light is incident on the second light guide element, Another portion of the third light is incident on the third light guiding element.

4. The projector according to claim 1 or 2, wherein: The cross-sectional area of ​​the first emission end is larger than the cross-sectional area of ​​the first incident end, The cross-sectional area of ​​the second emission end is larger than the cross-sectional area of ​​the second incident end, A cross-sectional area of ​​the third emission end is greater than a cross-sectional area of ​​the third incident end.

5. The projector according to claim 1 or 2, wherein: A first length from the first incident end to the first emission end is greater than or equal to 8 mm and less than or equal to 25 mm, A second length from the second incident end to the second emission end is greater than or equal to 8 mm and less than or equal to 25 mm, A third length from the third incident end to the third emission end is greater than or equal to 8 mm and less than or equal to 25 mm.

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

7. The projector according to claim 1 or 2, wherein: The focus of the first parallelizing element is located on the side of the first light source opposite to the emission side of the first light, The focus of the second parallelizing element is located on the side of the second light source opposite to the emission side of the second light, The focus of the third parallelizing element is located on a side of the third light source opposite to an emission side of the third light.

8. The projector according to claim 7, wherein: When the first length is 1, the distance between the position of the focus of the first parallelizing element and the light emitting surface of the first light source from which the first light is emitted is greater than or equal to 0.1 and less than or equal to 0.

5.

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

10. The projector according to claim 1 or 2, wherein: The first light guide element, the second light guide element and the third light guide element are hollow. Reflective films are provided on inner side surfaces of the first light guide element, the second light guide element, and the third light guide element.

11. The projector according to claim 1 or 2, wherein: When viewed along the optical axis of the first parallelizing element, the first parallelizing element covers the first emission end. When viewed along the optical axis of the second parallelizing element, the second parallelizing element covers the second emission end, When viewed along the optical axis of the third parallelizing element, the third parallelizing element covers the third emission end.

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

13. The projector according to claim 3, wherein: The first polarizing element is fixed to the first parallelizing element, The second polarizing element is fixed to the second parallelizing element, The third polarization element is fixed to the third parallelizing element.

14. The projector according to claim 5, wherein: The cross-sectional shape of the first light guide element is rectangular, The cross-sectional shape of the second light guide element is rectangular, The cross-sectional shape of the third light guide element is rectangular, When the inclination angle of the side surfaces including the short sides of the first light guide element, the second light guide element and the third light guide element is α, 7°≤α≤22°, When the inclination angle of the side surfaces including the long sides of the first light guide element, the second light guide element and the third light guide element is β, 14°≤β≤36°, A reflective film is provided on the inner side surfaces of the first light guide element, the second light guide element and the third light guide element. When the reflectivity of the reflective film is the highest, the incident angle of the light incident on the reflective film is θ in When 60°≤θ in ≤90°.

15. The projector according to claim 3, wherein: The projector has: a fourth polarizing element disposed between the first light modulating element and the light synthesizing element, transmitting a portion of the light emitted from the first light modulating element having a fourth polarized light component and absorbing another portion; a fifth polarizing element disposed between the second light modulating element and the light combining element, transmitting a portion of the light emitted from the second light modulating element having a fifth polarized light component and absorbing the other portion; and The sixth polarizing element is disposed between the third light modulator and the photosynthesizing element, and transmits a portion of the light having the sixth polarized light component among the light emitted from the third light modulator and absorbs the other portion.

Images