Lighting device and projector

Abstract

To provide a lighting device capable of detecting information on the intensity of color light emitted from a light source and being easily configured in a small size.SOLUTION: According to this embodiment, a lighting device includes a first light source for emitting first light of a first wavelength band, a second light source for emitting second light of a second wavelength band different from the first wavelength band, a color synthesizing element having a first surface and a second surface different from the first surface, and a light-receiving sensor for receiving first light and second light. The color synthesizing element has a substrate and a reflection film laminated on the substrate. Transmittance in the first wavelength band in the reflection film is greater than reflectance, and the reflectance in the first wavelength band is larger than 0%. Transmittance in the second wavelength band in the reflection film is smaller than reflectance, and the reflectance in the second wavelength band is larger than 0%. First light is incident on the first surface, and second light is incident on the second surface. A light-receiving sensor receives light reflected at the first surface of the first light, and light transmitted through the second surface of the second light.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002]

[0003] Conventionally, there has been known a projector that includes a light source that emits colored light, a light modulation device that modulates the colored light emitted from the light source in accordance with image information to generate image light, and a projection optical system that enlarges and projects the image light emitted from the light modulation device onto a projection surface such as a screen. The projector includes, for example, a light source device that includes a blue light source that emits blue light, an excitation light source that is provided separately from the blue light source and also emits blue light, and a phosphor that is excited by the blue light emitted from the excitation light source and emits yellow light. In such a projector, white light containing blue light and yellow light is emitted from the light source device, and each colored light contained in the white light is converted into image light by a common light modulation device or a light modulation device provided for each colored light.

[0003] The above-mentioned projectors use, for example, laser diodes (LDs) or light-emitting diodes (LEDs) as blue light sources or excitation light sources. The brightness and intensity of the light emitted from the LDs or LEDs of the light source device change depending on factors such as the length of time the projector and light source device have been in use, the temperature during use, and the applied voltage. Changes in the brightness and intensity of the light from the light source device affect the color balance and image quality of the image enlarged and projected onto the projection surface. Therefore, a configuration has been proposed that detects the brightness and intensity of a portion of the colored light emitted from the light source device and determines the condition and degree of deterioration of the light source in the projector.

[0004] For example, Patent Document 1 discloses a projector equipped with a detection device that detects the luminance of a portion of each of blue light and red light. In the projector of Patent Document 1, red light and green light emitted from a first light source unit and blue light emitted from a second light source unit are superimposed on the same optical path, and then separated onto different optical paths for each color by a filter that separates light within a predetermined wavelength range. The detection device detects the luminance of the blue light that has passed through the reflecting mirror after being separated onto the optical path of the blue light by the filter, and detects the luminance of the red light that has passed through the reflecting mirror after being separated onto an optical path different from that of the blue light by the filter. In the projector of Patent Document 1, the color balance of the projected image is adjusted based on information regarding the luminance of the blue light and the luminance of the red light obtained by the detection device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-114738 Summary of the Invention [Problem to be solved by the invention]

[0006] In the technology disclosed in the above-mentioned Patent Document 1, a detection device is disposed on each of a reflecting mirror through which a portion of incident blue light passes and a reflecting mirror through which a portion of incident red light passes, which may result in an increase in the size of the projector and a complex configuration. In other words, there has been a demand for a small, easily configured lighting device that can detect information regarding the intensity of colored light emitted from a light source, and a projector equipped with such a lighting device. [Means for solving the problem]

[0007] An illumination device according to one embodiment of the present invention includes a first light source that emits first light in a first wavelength band, a second light source that emits second light in a second wavelength band different from the first wavelength band, a color combining element having a first surface and a second surface different from the first surface, and a light receiving sensor that receives the first light and the second light. reflective film and. The transmittance of the reflective film in a first wavelength band is greater than the reflectance, and the reflectance in the first wavelength band is greater than 0%. The transmittance of the reflective film in a second wavelength band is less than the reflectance, and the transmittance in the second wavelength band is greater than 0%. The first light is incident on the first surface, and the second light is incident on the second surface. The light-receiving sensor receives the first light reflected by the first surface and the second light transmitted by the second surface. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a projector according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram of an illumination device of the projector of FIG. [Figure 3] 3 is a schematic diagram showing the transmittance and reflectance of a reflective film of a color combining element of the lighting device of FIG. 2. [Figure 4] 3 is a schematic diagram showing the transmittance and reflectance of a reflective film made of a metal thin film when the reflective film is provided on the color combining element of the lighting device of FIG. 2. FIG. [Figure 5] 3 is a schematic diagram of an electrical signal output from a light-receiving sensor of the lighting device of FIG. 2. FIG. [Figure 6] 10 is a schematic diagram illustrating an electrical signal output from a light-receiving sensor of a conventional lighting device. [Figure 7] 3 is a schematic diagram showing the spectrum of yellow light emitted from the light source of the lighting device of FIG. 2. [Figure 8] FIG. 10 is a schematic diagram of a lighting device according to a second embodiment. [Figure 9] FIG. 10 is a schematic diagram of a lighting device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each drawing, the scale of the dimensions of some components may be changed to make the components easier to see.

[0010] [First embodiment] First, a first embodiment of the present invention will be described with reference to FIGS.

[0011] (projector) FIG. 1 is a schematic diagram showing the configuration of a projector 1000 according to a first embodiment of the present invention. The projector 1000 is a projection-type display device that displays an image or video on a screen SCR. The projector 1000 includes an illumination device 100, a color separation optical system 200, field lenses 300R, 300G, and 300B, light modulation devices 400R, 400G, and 400B, a color synthesis optical system 500, and a projection optical system 600. The projector 1000 is a three-plate projector having three light modulation devices.

[0012] The illumination device 100 emits white light WL containing blue light BL, green light GL, and red light RL toward the color separation optical system 200. The red light RL, green light GL, and blue light BL are illumination lights in the projector 1000. In the following description, at least one of the blue light BL, green light GL, and red light RL emitted from the illumination device 100 may be referred to as colored light. The configuration of the illumination device 100 will be described later.

[0013] The color separation optical system 200 separates incident white light WL into red light RL, green light GL, and blue light BL, and separates each color light onto a separate optical path. The color separation optical system 200 includes, for example, dichroic mirrors 210 and 220, total reflection mirrors 230, 240, and 250, and relay lenses 260 and 270.

[0014] The dichroic mirror 210 is disposed on the optical path of the white light WL emitted from the illumination device 100. The dichroic mirror 210 transmits the red light RL and reflects the green light GL and blue light BL. Of the white light WL incident on the dichroic mirror 210, the red light RL and the green light GL and blue light BL are separated into different optical paths. The red light RL is transmitted through the dichroic mirror 210 and emitted toward the total reflection mirror 230. The green light GL and blue light BL are reflected by the dichroic mirror 210 and emitted toward the dichroic mirror 220.

[0015] The dichroic mirror 220 is disposed on a common optical path of the green light GL and blue light BL emitted from the dichroic mirror 210. The dichroic mirror 220 transmits the blue light BL and reflects the green light GL. The green light GL and blue light BL incident on the dichroic mirror 220 are separated into different optical paths. The green light GL is reflected by the dichroic mirror 220 and emitted toward the light modulation device 400G. The blue light BL is transmitted through the dichroic mirror 220 and emitted toward the total reflection mirror 240.

[0016] Total reflection mirror 230 is disposed on the optical path of red light RL emitted from dichroic mirror 210, and reflects the incident red light RL toward optical modulation device 400R. Total reflection mirror 240 is disposed on the optical path of blue light BL emitted from dichroic mirror 210, and reflects the incident blue light BL toward total reflection mirror 250. Total reflection mirror 250 is disposed on the optical path of blue light BL emitted from total reflection mirror 240, and reflects the incident blue light BL toward optical modulation device 400B.

[0017] The relay lens 260 is disposed on the optical path of the blue light BL between the dichroic mirror 220 and the total reflection mirror 240. The relay lens 270 is disposed on the optical path of the blue light BL between the total reflection mirror 240 and the total reflection mirror 250. The optical path length of the blue light BL from the dichroic mirror 210 to the optical modulation device 400B is longer than the optical path length of the red light RL from the dichroic mirror 210 to the optical modulation device 400R and the optical path length of the green light GL from the dichroic mirror 210 to the optical modulation device 400G. If a relay lens were not disposed on the optical path of the blue light BL, the optical loss of the blue light BL would be greater than the optical losses of the red light RL and the green light GL. By disposing the relay lenses 260 and 270 as described above, the optical loss of the blue light BL is compensated for.

[0018] Field lens 300R is disposed on the optical path of red light RL emitted from total reflection mirror 230. Field lens 300R aligns the traveling direction of light in a peripheral region of red light RL, which has an illuminance lower than a predetermined illuminance, on a plane intersecting the optical axis of the incident red light RL, thereby suppressing a reduction in the amount of light in the peripheral region, and emits red light RL toward optical modulation device 400R.

[0019] Field lens 300G is disposed on the optical path of green light GL emitted from dichroic mirror 220. Field lens 300G aligns the traveling direction of light in a peripheral region of green light GL, which has an illuminance lower than a predetermined illuminance, on a plane intersecting the optical axis of the incident green light GL, thereby suppressing a reduction in the amount of light in the peripheral region, and emits green light GL toward optical modulation device 400G.

[0020] Field lens 300B is disposed on the optical path of blue light BL emitted from total reflection mirror 250. Field lens 300B aligns the traveling direction of light in a peripheral region of blue light BL, which has an illuminance lower than a predetermined illuminance, on a plane intersecting the optical axis of the incident blue light BL, thereby suppressing a reduction in the amount of light in the peripheral region, and emits blue light BL toward optical modulation device 400B.

[0021] Light modulation device 400R is disposed on the optical path of red light RL that is reflected by total reflection mirror 230 and emitted from field lens 300R. Light modulation device 400R modulates the incident red light RL in accordance with image information input from an image output device (not shown), converts it into red image light, and emits the red image light toward color synthesis optical system 500. The image output device is, for example, a personal computer or a portable terminal device.

[0022] Light modulation device 400G is disposed on the optical path of green light GL that is reflected by dichroic mirror 220 and emitted from field lens 300G. Light modulation device 400G modulates the incident green light GL in accordance with image information input from an image output device (not shown), converts it into green image light, and emits the green image light toward color synthesis optical system 500.

[0023] Light modulation device 400B is disposed on the optical path of blue light BL that is reflected by total reflection mirror 250 and emitted from field lens 300B. Light modulation device 400B modulates the incident blue light BL in accordance with image information input from an image output device (not shown), converts it into blue image light, and emits the blue image light toward color synthesis optical system 500.

[0024] Each of the light modulation devices 400B, 400G, and 400R uses, for example, a transmissive liquid crystal panel. Polarizing plates are arranged in each of the incident-side and exit-side regions of the liquid crystal panel. That is, each of the light modulation devices 400R, 400G, and 400B has an incident-side polarizing plate, a liquid crystal panel, and an exit-side polarizing plate arranged in this order from the incident side to the exit side along the optical path of the incident color light.

[0025] The incident-side polarizers of the optical modulation devices 400B, 400G, and 400R are arranged on the optical paths of the red light RL, green light GL, and blue light BL emitted from the field lenses 300R, 300G, and 300B. The incident-side polarizers emit a predetermined polarized component of the incident colored light and block components of the colored light other than the predetermined polarized component. The predetermined polarized component is, for example, a polarizer that blocks a colored light incident on the incident-side polarizer such that the vibration plane of the colored light is the same as the plane of incidence of the incident-side polarizer. parallel to The incident-side polarizer is, for example, an absorptive or reflective polarizer having a transmission axis for a predetermined polarization. In order to suppress return light and stray light from the incident-side polarizer to field lenses 300R, 300G, and 300B, the incident-side polarizer is preferably an absorptive polarizer.

[0026] The liquid crystal panels of the optical modulation devices 400B, 400G, and 400R have a display area and a peripheral area surrounding the display area in a plane intersecting the optical axis of the incident color light. The display area has a plurality of pixels arranged two-dimensionally in a plane intersecting the optical axis of the incident color light.

[0027] The liquid crystal panels of the optical modulation devices 400B, 400G, and 400R have a counter substrate (not shown), a liquid crystal layer, and an element substrate, which are arranged in this order along the direction in which the colored light travels. The counter substrate has a surface facing the liquid crystal layer in the display area on which counter electrodes for a plurality of pixels and various wirings are formed. The element substrate has a surface facing the liquid crystal layer in the display area on which multiple element electrodes, switching elements, and various wirings corresponding to the multiple counter electrodes are formed. The switching elements are, for example, polysilicon thin film transistors (TFTs).

[0028] Each pixel of the liquid crystal panel of the optical modulation devices 400B, 400G, and 400R modulates the vibration direction of the incident red light RL, green light GL, and blue light BL by the operation of a switching element in response to an electrical signal corresponding to the image information of the color light. The optical modulation devices 400R, 400G, and 400B generate red image light, green image light, and blue image light by the operation of the switching element.

[0029] The exit-side polarizing plates of the optical modulation devices 400B, 400G, and 400R are arranged on the optical paths of the red image light, green image light, and blue image light emitted from the liquid crystal panels arranged corresponding to each color light. The exit-side polarizing plate emits a predetermined polarized component of the incident image light and blocks components of the image light other than the predetermined polarized component. The predetermined polarized component is, for example, a polarized component that is polarized when the vibration plane of the color light incident on the exit-side polarizing plate is the same as the incident plane of the exit-side polarizing plate. parallel to The light emitted from the exit side is polarized light P. The exit side polarizer is, for example, an absorptive or reflective polarizer having a transmission axis for a predetermined polarized light. In order to suppress return light and stray light from the exit side polarizer to the liquid crystal panel, the exit side polarizer is preferably an absorptive polarizer.

[0030] The color combining optical system 500 is disposed in a region where the optical path of the red image light emitted from the exit-side polarizing plate of the light modulation device 400R, the optical path of the green image light emitted from the exit-side polarizing plate of the light modulation device 400G, and the optical path of the blue image light emitted from the exit-side polarizing plate of the light modulation device 400B intersect. The color combining optical system 500 combines the incident three-color image light and emits the generated full-color image light toward the projection optical system 600.

[0031] The color combining optical system 500 is configured, for example, by a cross dichroic prism. The cross dichroic prism is configured by four right-angle prisms and two reflective films (not shown) and forms a rectangular parallelepiped. The reflective films are configured, for example, by a dielectric multilayer film. The cross dichroic prism has three entrance surfaces onto which three-color image light enters, an exit surface from which full-color image light exits, a first reflecting surface, and a second reflecting surface. The three entrance surfaces of the cross dichroic prism form three side surfaces of the rectangular parallelepiped and face the exit surfaces of the exit-side polarizers of the light modulation devices 400B, 400G, and 400R. The exit surface of the cross dichroic prism forms the remaining side surface of the rectangular parallelepiped and faces the entrance surface of the projection optical system 600. The first reflecting surface is located on one diagonal when the rectangular parallelepiped is viewed in a plane, and is arranged so as to form a 45° angle with the entrance surface of the cross dichroic prism facing the exit surface of the exit-side polarizing plate of the light modulation device 400B and the exit surface of the cross dichroic prism. The first reflecting surface transmits incident red and green image light and reflects blue image light. The second reflecting surface is located on the other diagonal when the rectangular parallelepiped is viewed in a plane, and is arranged so as to form a 45° angle with the entrance surface of the cross dichroic prism facing the exit surface of the exit-side polarizing plate of the light modulation device 400R and the exit surface of the cross dichroic prism. The second reflecting surface reflects incident red image light and transmits green and blue image light.

[0032] The red image light emitted from the exit surface of the exit-side polarizing plate of the light modulation device 400R enters the cross dichroic prism, transmits a portion of the first reflecting surface, and is reflected by the second reflecting surface toward the exit surface. The green image light emitted from the exit surface of the exit-side polarizing plate of the light modulation device 400G enters the cross dichroic prism, transmits the first and second reflecting surfaces, and proceeds toward the exit surface. The blue image light emitted from the exit surface of the exit-side polarizing plate of the light modulation device 400B enters the cross dichroic prism, transmits a portion of the second reflecting surface, and is reflected by the first reflecting surface toward the exit surface. The red image light reflected by the second reflecting surface, the green image light transmitted through the first and second reflecting surfaces, and the blue image light reflected by the first reflecting surface are combined together to generate full-color image light.

[0033] The projection optical system 600 is disposed on the optical path of the image light emitted from the color combining optical system 500. The projection optical system 600 projects the incident image light onto a screen SCR, and enlarges and displays the image transmitted from an image forming device (not shown) to the light modulation devices 400B, 400G, and 400R on the screen SCR. The projection optical system 600 is composed of one or more optical lenses. Examples of optical lenses include a plano-convex lens, a plano-concave lens, a biconvex lens, a biconcave lens, a meniscus lens, an aspherical lens, and a free-form lens.

[0034] (Lighting equipment) 2 is a schematic diagram showing the configuration of the illumination device 100 of the first embodiment. As shown in FIG. 2, the illumination device 100 includes a light source 40, optical lenses 52, 54, and 56, a light source 20, optical lenses 32, 34, and 36, a color combining element 60, a light-receiving sensor 90, a first lens array 71, a second lens array 76, a polarization conversion element 80, a superimposing lens 82, and a control device 120.

[0035] The light source 40 includes a light-emitting element 50. The light-emitting element 50 is disposed on the +X side and the -Y side of the light source 20 and the optical lenses 32, 34, 36, and overlaps with the light source 20 and the optical lenses 32, 34, 36 in the Z direction. The light source 40 corresponds to a first light source.

[0036] The light-emitting element 50 emits blue light BL from its light-emitting surface 50e toward the +Y side along the Y direction and the optical axis AX2. The blue light BL emitted from the light-emitting element 50 corresponds to the first light. The optical axis AX2 of the blue light BL emitted from the light-emitting element 50 is perpendicular to the optical axis AX1 of the fluorescence FL emitted from the light source 20. The light-emitting surface 50e of the light-emitting element 50 is an end face of the light-emitting element 50 extending substantially parallel to the XZ plane on the +Y side. An optical element such as a lens or a diffuser (not shown) may be disposed on the +Y side of the light-emitting element 50. The blue wavelength band of the blue light BL emitted from the light-emitting element 50 is different from the yellow wavelength band and corresponds to the first wavelength band. The blue wavelength band of the blue light BL emitted from the light-emitting element 50 is the same blue wavelength band as the blue light BL incident on the color separation optical system 200 described with reference to FIG. 1, e.g., a wavelength band of 400 nm to 470 nm. The light-emitting element 50 is, for example, an LED that emits blue light BL. The blue light BL emitted from the light emitting element 50 is unpolarized and randomly polarized.

[0037] The number of light-emitting elements 50 is appropriately determined depending on the amount of blue light BL required for the projector 1000 and the color balance of the image projected by the projector 1000. When the illumination device 100 has a plurality of light-emitting elements 50, for example, the plurality of light-emitting elements 50 are arranged at intervals from one another within a region (not shown) in the XZ plane centered on the optical axis AX2 of the blue light BL.

[0038] As shown in FIG. 2, the optical lenses 52, 54, and 56 are disposed on the optical path of the blue light BL emitted from the light source 40, are disposed on the +Y side of the light source 40, and overlap with the light source 40 in the X and Z directions. The optical lenses 52, 54, and 56 are disposed sequentially along the Y direction from the -Y side to the +Y side, with intervals between them. The optical axis of the blue light BL passing through the optical lenses 52, 54, and 56 is parallel to the optical axis AX2 of the blue light BL emitted from the light source 40 and is aligned in a straight line with the optical axis AX2. The optical lenses 52, 54, and 56 collimate the blue light BL emitted from the light source 40 along the Y direction. That is, the blue light BL parallel to the Y direction is emitted from the +Y side exit surface of the optical lens 56.

[0039] The entrance surface of each of the optical lenses 52, 54, and 56 is a flat surface parallel to the XZ plane. The exit surface of each of the optical lenses 52, 54, and 56 is a convex surface protruding toward the +Y side. That is, each of the optical lenses 52, 54, and 56 is a plano-convex lens having a convex surface toward the +Y side. Note that, as long as the blue light BL can be collimated along the Y direction, at least one of the optical lenses 52, 54, and 56 may be a biconvex lens, a biconcave lens, a meniscus lens, an aspherical lens, a free-form lens, or the like, other than a plano-convex lens. As long as the blue light BL can be collimated along the Y direction, one or two of the optical lenses 52, 54, and 56 may be omitted, or another optical lens may be added to the optical lenses 52, 54, and 56.

[0040] The light source 20 includes a wavelength conversion member 22, a plurality of light emitting elements 10, mirrors 24 and 26, and an angle conversion member 28. The light source 20 corresponds to a second light source.

[0041] The wavelength conversion member 22 is formed in an elongated quadrangular prism shape and has four side surfaces including side surfaces 22a and 22b, and two end surfaces 22c and 22d. In the following description of the lighting device 100, the direction in which the wavelength conversion member 22 extends is referred to as the X direction, a direction perpendicular to the X direction is referred to as the Y direction, and a direction perpendicular to the X and Y directions is referred to as the Z direction. One side in the X direction is referred to as the -X side, and the other side in the X direction is referred to as the +X side. One side in the Y direction is referred to as the -Y side, and the other side in the Y direction is referred to as the +Y side. One side in the Z direction is referred to as the -Z side, and the other side in the Z direction is referred to as the +Z side.

[0042] The sides of the wavelength conversion member 22 parallel to the X direction are longer than the sides of the wavelength conversion member 22 parallel to the Y direction and the sides of the wavelength conversion member 22 parallel to the Z direction. The sides of the wavelength conversion member 22 parallel to the Y direction and the Z direction have the same length. The side surfaces 22a and 22b of the wavelength conversion member 22 extend parallel to the XZ plane including the X and Z directions and have a rectangular shape with long sides parallel to the X direction. The side surface 22a is located on the -Y side of the side surface 22b. The end surfaces 22c and 22d of the wavelength conversion member 22 extend parallel to the YZ plane including the Y and Z directions and have a square shape. The end surface 22c is located on the -X side of the end surface 22d.

[0043] The wavelength conversion member 22 contains a phosphor and emits fluorescence FL when irradiated with excitation light EL. That is, the wavelength conversion member 22 converts the incident excitation light EL into fluorescence FL having a wavelength band different from that of the excitation light EL. In this embodiment, the wavelength conversion member 22 converts the excitation light EL in a blue wavelength band into fluorescence FL in a yellow wavelength band. The yellow wavelength band corresponds to the second wavelength band and includes a green wavelength band that is the same as the green light GL incident on the color separation optical system 200 described with reference to FIG. 1 and a red wavelength band that is the same as the red light RL. The green wavelength band is a wavelength band that is visually recognized as green in the visible wavelength band, for example, a wavelength band of 490 nm to 600 nm. The red wavelength band is a wavelength band that is visually recognized as red in the visible wavelength band, for example, a wavelength band of 600 nm to 740 nm.

[0044] The wavelength conversion member 22 includes a ceramic phosphor made of a polycrystalline phosphor that converts the wavelength of the excitation light EL into fluorescence FL. Specifically, the material of the wavelength conversion member 22 is, for example, YAG:Ce, which includes an yttrium-aluminum-garnet (YAG)-based phosphor and contains cerium (Ce) as an activator. Examples of materials that can be used for the wavelength conversion member 22 include a material obtained by mixing and solid-phase reaction raw material powders containing constituent elements such as yttrium oxide (YO), aluminum oxide (AlO), and cerium oxide (CeO); Y-Al-O amorphous particles obtained by a wet method such as coprecipitation or a sol-gel method; or YAG particles obtained by a gas-phase method such as spray drying, flame pyrolysis, or a thermal plasma method.

[0045] Note that the wavelength conversion member 22 may include a single crystal phosphor that converts the wavelength of the excitation light EL into fluorescence FL instead of the polycrystalline phosphor described above. The wavelength conversion member 22 may be made of fluorescent glass that converts the wavelength of the excitation light EL into fluorescence FL. The wavelength conversion member 22 may be made of a material in which a large number of phosphor particles are dispersed in a binder made of glass or resin, and may convert the wavelength of the excitation light EL into fluorescence FL.

[0046] 2, the plurality of light-emitting elements 10 are arranged at the same positions in the Y direction on the -Y side of the side surface 22a of the wavelength conversion member 22, are arranged at intervals in the X direction on the XZ plane, and are arranged at the same positions in the Z direction. The plurality of light-emitting elements 10 are supported by a substrate or a support member (not shown) on which wiring or the like for supplying electrical signals or the like to the light-emitting elements 10 is provided.

[0047] Each light-emitting element 10 emits excitation light EL from its light-emitting surface 10e toward the +Y side along the Y direction. The light-emitting surface 10e of the light-emitting element 10 is an end face extending substantially parallel to the XZ plane on the +Y side of the light-emitting element 10 and faces the side surface 22a of the wavelength conversion member 22. In the Y direction, an optical element such as a lens or a diffuser (not shown) may be disposed between the light-emitting element 10 and the wavelength conversion member 22. As described above, the blue wavelength band of the excitation light EL is a wavelength band that can excite the wavelength conversion member 22 to emit fluorescence FL, for example, a wavelength band of 400 nm to 480 nm. The peak wavelength of the excitation light EL is, for example, 445 nm, which is equivalent to the excitation wavelength of the wavelength conversion member 22. The light-emitting element 10 is, for example, an LED that emits excitation light EL. The excitation light EL emitted from the light-emitting element 10 is unpolarized and randomly polarized.

[0048] When excitation light EL emitted from the light emitting element 10 enters the wavelength conversion member 22 from the side surface 22a, the phosphor inside the wavelength conversion member 22 is excited, and fluorescence FL is emitted in multiple directions from light-emitting points generated inside the wavelength conversion member 22. The fluorescence FL emitted from the phosphor inside the wavelength conversion member 22 is repeatedly totally reflected by the side surfaces 22a and 22b and by the side surfaces extending parallel to the XY plane including the X and Y directions, and travels toward the end surfaces 22c and 22d. The wavelength conversion member 22 acts as a light-guiding member for the fluorescence FL.

[0049] The mirror 24 is disposed on the +Y side of the side surface 22b of the wavelength conversion member 22 and abuts against the side surface 22b. The mirror 24 reflects part of the excitation light EL that enters the inside of the wavelength conversion member 22 from the side surface 22a, travels inside the wavelength conversion member 22, and reaches the end surface 22c from the -Y side. The excitation light EL reflected at the side surface 22b by the mirror 24 is reused for exciting the wavelength conversion member 22. The mirror 24 may also reflect the fluorescence FL that is guided inside the wavelength conversion member 22 and enters the side surface 22b from the -Y side. The mirror 24 is made of, for example, a dielectric multilayer film or a metal thin film formed separately from the wavelength conversion member 22, and is formed directly on the +Y side of the side surface 22b.

[0050] If the amount of excitation light EL that can enter the wavelength conversion member 22 from the side surface 22a and then exit from the side surface 22b to the +Y side is small, the mirror 24 may be omitted.

[0051] The mirror 26 is disposed on the -X side of the end face 22c of the wavelength conversion member 22 and abuts against the end face 22c. The mirror 26 reflects the fluorescence FL that is guided inside the wavelength conversion member 22 and reaches the end face 22c from the +X side. The fluorescence FL reflected by the mirror 26 at the end face 22c is guided again inside the wavelength conversion member 22 and travels toward the end face 22d. The mirror 26 is made of, for example, a dielectric multilayer film or a metal thin film formed separately from the wavelength conversion member 22, and is formed directly on the -X side of the end face 22c. The mirror 26 may also be made of a substrate made of glass or the like and a reflective film such as a dielectric multilayer film or a metal film formed on one surface of the substrate.

[0052] Angle conversion member 28 is disposed on the +X side of end surface 22d of wavelength conversion member 22. Angle conversion member 28 is formed, for example, in the shape of a truncated quadrangular pyramid. Angle conversion member 28 has an end surface on the -X side, an end surface on the +X side, and four side surfaces. Fluorescence FL, which is guided from the -X side to end surface 22d of wavelength conversion member 22 and emitted from end surface 22d, is incident on the -X side end surface of angle conversion member 28. Fluorescence FL is emitted as yellow light YL from the +X side end surface of angle conversion member 28.

[0053] At least a portion of the fluorescence FL emitted from end face 22d of wavelength conversion member 22 to the +X side at a wide angle centered on the X direction is totally reflected by the four side faces of angle conversion member 28 toward the +X side end face of angle conversion member 28. The optical axis AX1 of the fluorescence FL in angle conversion member 28 is parallel to the X direction. The cross section of angle conversion member 28 orthogonal to the optical axis AX1 expands from the -X side end face toward the +X side end face. That is, the +X side end face of angle conversion member 28 is larger than the -X side end face.

[0054] The fluorescence FL incident on the angle conversion member 28 changes its direction so as to approach a direction parallel to the optical axis AX1 while propagating inside the angle conversion member 28 and undergoes total reflection at the side surface, as described above. The angle conversion member 28 converts the emission angle distribution of the fluorescence FL emitted from the end surface 22d of the wavelength conversion member 22. Specifically, the etendue of light, which is defined as the product of the area of ​​the light emission region and the solid angle of the light, i.e., the maximum emission angle, is preserved, and therefore the etendue of the fluorescence FL is preserved both before it enters the angle conversion member 28 and after it is emitted from the angle conversion member 28. As described above, because the area of ​​the +X side end surface of the angle conversion member 28 is larger than the area of ​​the -X side end surface, from the perspective of etendue preservation, the angle conversion member 28 makes the maximum emission angle of the fluorescence FL from the +X side end surface smaller than the maximum incident angle of the fluorescence FL to the -X side end surface.

[0055] The -X side end face of the angle conversion member 28 faces the end face 22d of the wavelength conversion member 22 and is fixed to the wavelength conversion member 22 via an optical adhesive (not shown). That is, the angle conversion member 28 and the wavelength conversion member 22 are connected to each other in the X direction via the optical adhesive, and no gap is provided between the wavelength conversion member 22 and the angle conversion member 28. The angle conversion member 28 is made of a transparent material such as optical glass. The refractive index of the angle conversion member 28 is preferably close to the refractive index of the wavelength conversion member 22.

[0056] The angle conversion member 28 may be configured by a compound parabolic concentrator (CPC) instead of the truncated quadrangular pyramid-shaped member as described above and shown in the drawings. If the etendue of the fluorescence FL emitted from the wavelength conversion member 22 is within the range of the conditions, the angle conversion member 28 may be omitted.

[0057] Fluorescence FL is emitted in the X direction as yellow light YL from the end face on the +X side of the angle conversion member 28. The yellow light YL emitted from the light source 20 is unpolarized light, for example, randomly polarized light, and corresponds to the second light.

[0058] The optical lenses 32, 34, and 36 are disposed on the optical path of the fluorescence FL emitted from the light source 20, are disposed on the +X side of the light source 20, and overlap with the light source 20 in the Y and Z directions. The optical lenses 32, 34, and 36 are disposed sequentially along the X direction from the -X side to the +X side, with intervals between them. The optical axis of the fluorescence FL passing through the optical lenses 32, 34, and 36 is parallel to the optical axis AX1 of the fluorescence FL emitted from the light source 20 and aligned in a straight line with the optical axis AX1. The optical lenses 32, 34, and 36 collimate the fluorescence FL emitted from the light source 20 along the X direction. That is, the fluorescence FL is emitted as yellow light YL, i.e., fluorescence FL parallel to the X direction, from the +X side exit surface of the optical lens 36.

[0059] The entrance surface of each of the optical lenses 32, 34, and 36 is a flat surface parallel to the YZ plane. The exit surface of each of the optical lenses 32, 34, and 36 is a convex surface protruding toward the +X side. That is, each of the optical lenses 32, 34, and 36 is a plano-convex lens having a convex surface toward the +X side. Note that, as long as the fluorescence FL can be collimated along the X direction, at least one of the optical lenses 32, 34, and 36 may be a biconvex lens, a biconcave lens, a meniscus lens, an aspherical lens, a free-form lens, or the like, other than a plano-convex lens. As long as the fluorescence FL can be collimated along the X direction, one or two of the optical lenses 32, 34, and 36 may be omitted, or other optical lenses may be added to the optical lenses 32, 34, and 36.

[0060] The optical axes AX1 and AX2 intersect at a predetermined position on the +X side of the optical lens 36 and on the +Y side of the optical lens 56. The color combining element 60 is disposed in a region that includes the predetermined position where the optical axes AX1 and AX2 intersect, and where yellow light YL emitted from the optical lens 36 to the +X side along the X direction and blue light BL emitted from the optical lens 56 to the +Y side along the Y direction overlap. The color combining element 60 includes a substrate 62 and a reflective film 64, and has reflective surfaces 60a and 60b.

[0061] The substrate 62 is formed of a material that transmits light in the visible wavelength range and is translucent to light in the visible wavelength range. When viewed along the Z direction, the plate surface of the substrate 62 is inclined at 45° with respect to the Y and X directions and at 45° with respect to the YZ and XZ planes. The plate surface of the substrate 62 moves from the -Y side to the +Y side as it moves from the -X side to the +X side. The size of the substrate 62 and the reflective film 64 in the X direction is approximately the same as the size in the X direction of blue light BL that passes through the substrate 62 from the -Y side and enters the reflective film 64, with an appropriate margin on the periphery. Similarly, the size of the substrate 62 and the reflective film 64 in the Y direction is approximately the same as the size in the Y direction of yellow light YL that enters the reflective film 64 from the -X side, with an appropriate margin on the periphery. The Z-direction size of the substrate 62 and the reflective film 64 is approximately the same as the larger of the Z-direction size of the yellow light YL incident on the reflective film 64 from the -X side and the Z-direction size of the blue light BL incident on the reflective film 64 through the substrate 62 from the -Y side, and is set with a moderate margin around the periphery.

[0062] The reflective film 64 is disposed on the +Y side surface of the substrate 62 of the color combining element 60 and abuts against the +Y side plate surface of the substrate 62. The reflective film 64 reflects a portion of the yellow light YL incident from the -X side along the X direction by the reflective surface 60b toward the +Y side along the Y direction, and transmits at least a portion of the remaining light. The reflective film 64 transmits a portion of the blue light BL incident from the -Y side along the Y direction, and reflects at least a portion of the remaining light toward the +X side along the X direction by the reflective surface 60a. The color combining element 60 combines the blue light BL that transmits through the reflective film 64 with the yellow light YL reflected by the reflective film 64 to generate white light WL, i.e., illumination light.

[0063] The reflective film 64 is, for example, a yellow reflective dichroic mirror (YDM) made of a dielectric multilayer film. The transmittance and reflectance of the reflective film 64 in the blue wavelength band and the yellow wavelength band, respectively, are controlled with high precision by adjusting conditions such as the refractive index difference between the low refractive index layers and the high refractive index layers that make up the dielectric multilayer film, the thickness of the low refractive index layers, the thickness of the high refractive index layers, and the number of layers.

[0064] The reflectance of the reflective film 64 in the blue wavelength band is at least greater than 0% but smaller than the transmittance of the reflective film 64 in the blue wavelength band. The reflectance of the reflective film 64 in the blue wavelength band is preferably 0.01% or greater and 10.00% or less, and more preferably 1.0% or greater and 5.0% or less. In the above case, the transmittance of the reflective film in the blue wavelength band is approximately 90.0% or greater and 99.0% or less. The transmittance of the reflective film 64 in the yellow wavelength band is at least greater than 0% but smaller than the reflectance of the reflective film 64 in the yellow wavelength band. The transmittance of the reflective film 64 in the yellow wavelength band is preferably 0.01% or greater and 10.00% or less, and more preferably 1.0% or greater and 5.0% or less. In the above case, the reflectance of the reflective film in the yellow wavelength band is approximately 90.0% or greater and 99.0% or less. These factors ensure that the amount of white light WL, i.e., illumination light, emitted from the lighting device 100 is sufficient, and the light-receiving sensor 90 can obtain sufficient information regarding the amount of each of the blue light BL and yellow light YL in the white light WL.

[0065] The lower limit of the reflectance of the reflective film 64 in the blue wavelength band is determined by the minimum light intensity ratio of the blue light BL incident on the color combining element 60 that can be clearly distinguished from background and noise and detected by the detection unit 91 of the light-receiving sensor 90. Similarly, the lower limit of the transmittance of the reflective film 64 in the yellow wavelength band is determined by the minimum light intensity ratio of the yellow light YL incident on the color combining element 60 that can be clearly distinguished from background and noise and detected by the detection unit 91 of the light-receiving sensor 90. If the reflectance of the reflective film 64 in the blue wavelength band exceeds the above-mentioned upper limit, the loss of the amount of white light WL emitted from the lighting device 100 will be excessively large. If the transmittance of the reflective film 64 in the yellow wavelength band exceeds the above-mentioned upper limit, the loss of the amount of white light WL emitted from the lighting device 100 will also be excessively large.

[0066] FIG. 3 is a schematic diagram showing the wavelength dependence of the transmittance and reflectance of colored light in a reflective film 64 made of YDM. Because there is almost no internal absorption in the substrate 62 and the reflective film 64, the sum of the transmittance and reflectance of colored light in the reflective film 64 can be considered to be 1, or 100%, as shown in FIG. 3. The transmittance of blue light BL and the reflectance of yellow light YL in the reflective film 64 are controlled with high precision during manufacturing. That is, because the reflective film 64 is made of YDM, the transmittance of colored light, which is proportional to the thickness of each layer constituting the dielectric multilayer film as YDM, is controlled with high precision during manufacturing. Therefore, the amount of blue light BL and yellow light YL emitted from the reflective film 64 toward the light-receiving sensor 90 is prevented from deviating from a predetermined range, improving the production yield of the light-receiving sensor 90. Furthermore, if the reflectance of yellow light YL or blue light BL from the +Y side surface of the reflective film 64, i.e., the reflective surface 60b, is measured, the transmittance of blue light BL or yellow light YL from the -Y side surface of the substrate 62, i.e., the reflective surface 60b, can be accurately determined by calculation without measurement.

[0067] As described above, since there is no internal absorption in the dielectric multilayer film serving as YDM, a large amount of yellow light YL is transmitted, i.e., a large amount of yellow light YL is incident on the light-receiving sensor 90, improving the signal-to-noise ratio of the light-receiving sensor 90. This simplifies measures to deal with stray light in the lighting device 100.

[0068] FIG. 4 is a schematic diagram showing the wavelength dependence of the transmittance and reflectance of colored light when a metal thin film is disposed on the +Y side surface of the substrate 62. In this case, the reflectance of colored light is approximately constant regardless of wavelength. Even if the thickness of the metal thin film changes, the reflectance of colored light remains constant, but the transmittance of colored light changes significantly. Within a given range of metal thin film thickness, the transmittance of colored light decreases dramatically as the thickness increases. Therefore, when a metal thin film is disposed on the +Y side surface of the substrate 62, it is difficult to control the thickness of the metal thin film and the transmittance of colored light during manufacturing, which reduces the production yield of the light-receiving sensor.

[0069] The -Y side surface of the reflective film 64 faces the exit surface of the optical lens 56 and the light receiving surface of the light receiving sensor 90, forms the reflective surface 60a of the color combining element 60, and corresponds to the first surface. The +Y side surface of the reflective film 64 faces the exit surface of the optical lens 36 and the light receiving surface of the first lens array 71, forms the reflective surface 60b of the color combining element 60, and corresponds to the second surface.

[0070] The light receiving sensor 90 is disposed on the optical axis AX1 on the +X side of the color combining element 60, and overlaps with the light source 20 and the color combining element 60 in the Y and Z directions. The light receiving sensor 90 is disposed on the optical path of the blue light BL and yellow light YL emitted from the color combining element 60 to the +X side along the X direction and the optical axis AX1.

[0071] The light-receiving sensor 90 includes a multicolor sensor capable of measuring the amount of light of multiple colors, i.e., multiple wavelength bands. Specifically, the light-receiving sensor 90 includes detection units 91, 92, and 93 capable of detecting colored light of different wavelength bands. The detection unit 91 detects the light intensity or amount of incident blue light BL. The detection unit 92 detects the light intensity or amount of green light GL contained in the incident yellow light YL. The detection unit 93 detects the light intensity or amount of red light RL contained in the incident yellow light YL. That is, in the lighting device 100, the amount of blue light BL and the amount of each of green light GL and red light RL contained in the yellow light YL are measured by a single multicolor sensor.

[0072] As described above, the light-receiving sensor 90 of this embodiment detects blue light BL in the blue wavelength band using one detector 91 and detects yellow light YL in the yellow wavelength band using two detectors 92 and 93. The light-receiving sensor 90 may also detect blue light BL using multiple detectors capable of detecting blue light in different wavelength bands within the blue wavelength band. In other words, the light-receiving sensor 90 may have multiple detectors capable of detecting colored light in different wavelength bands within a single color wavelength band. This allows complex fluctuations in the spectrum of colored light, including blue light BL and yellow light YL, to be detected as changes in the integral value. In a multicolor sensor, color filters or the like can be used to separately detect the integral of the light output within the measurement range of green light GL (i.e., the green light integral value) and the integral of the light output within the measurement range of red light RL (i.e., the red light integral value).

[0073] FIG. 5 is a schematic diagram showing an example of electrical signals, i.e., data, output from the light-receiving sensor 90. The light-receiving sensor 90 continuously outputs, in time series, an electrical signal SB indicating the amount of blue light BL detected by the detector 91, an electrical signal SG indicating the amount of green light GL detected by the detector 92, and an electrical signal SR indicating the amount of red light RL detected by the detector 93 to the control device 120. As shown in FIG. 5, the light-receiving sensor 90 does not generate a wait time between the output of the electrical signals SB and SG in one set and between the output of the electrical signals SG and SR in one set. If the brightness CL1 of the blue light BL and yellow light YL in one set is 100%, the brightness CL2 of the blue light BL and yellow light YL in the next set will vary from 100% to, for example, 85%. Between the time when the electrical signal SR is output and the time when the electrical signal SB in the next set is output, a data transfer time IT1 and a wait time IT2 for switching the detectors occur. This minimizes the time required for transmitting the electrical signals SB, SG, and SR in time series.

[0074] FIG. 6 is a schematic diagram showing an example of an electrical signal, i.e., data, output from a conventional light-receiving sensor. The conventional light-receiving sensor includes two sensors configured separately from each other. The two sensors include a first sensor for obtaining an electrical signal related to the amount of blue light and a second sensor for obtaining an electrical signal related to the amount of red light. As shown in FIG. 6, when the conventional light-receiving sensor is used, the time difference between the first and second sensors in the time series and the sum of the transfer time IT1 and waiting time IT2 at each sensor result in a longer transfer time for the electrical signals SB, SG, and SR in the time series compared to when the light-receiving sensor 90 of this embodiment is used.

[0075] The first lens array 71 is disposed on the optical axis AX2 on the +Y side of the color combining element 60, and overlaps with the light source 20 and the color combining element 60 in the X and Z directions. The first lens array 71 is disposed on the optical path of the blue light BL and yellow light YL emitted from the color combining element 60 to the +Y side along the Y direction and the optical axis AX2.

[0076] The first lens array 71 includes a plurality of microlenses 72. The microlenses 72 are arranged in a matrix within an XZ plane centered on the optical axis AX2. The microlenses 72 split the white light WL emitted from the color combining element 60 and incident from the -Y side into a plurality of partial beams within the XZ plane. When viewed along the Y direction, each microlens 72 has a rectangular shape that is approximately similar to the shape of the image forming area of ​​each of the light modulation devices 400B, 400R, and 400G, where multiple images are arranged. This allows each of the partial beams emitted from the first lens array 71 to efficiently enter the image forming area of ​​each of the light modulation devices 400B, 400G, and 400R. The microlenses 72 are, for example, plano-convex lenses with a convex surface on the +Y side.

[0077] The second lens array 76 is disposed on the +Y side of the first lens array 71, and overlaps with the first lens array 71 in the X and Z directions. The second lens array 76 is disposed on the optical path of the white light WL, which includes blue light BL and yellow light YL, emitted from the first lens array 71 to the +Y side along the Y direction and the optical axis AX2.

[0078] The second lens array 76 has a plurality of microlenses 77. The plurality of microlenses 72 are arranged in a matrix within an area of ​​the XZ plane centered on the optical axis AX2, and face the plurality of microlenses 72. The plurality of microlenses 77 correspond to the plurality of microlenses 72 of the first lens array 71. The second lens array 76 cooperates with the superimposing lens 82 to form each image of the plurality of microlenses 72 of the first lens array 71 near the image forming area of ​​each of the light modulation devices 400B, 400G, and 400R. The microlenses 77 are, for example, plano-convex lenses having a convex surface on the -Y side.

[0079] Each microlens 77 of the second lens array 76 has the same size in the XZ plane as each microlens 72 of the first lens array 71. However, the sizes in the XZ plane of the microlenses 72, 77 may be different from each other. Furthermore, the microlenses 72 of the first lens array 71 and the microlenses 77 corresponding to the microlenses 72 in the second lens array 72 are arranged in positions where the optical axes of the colored lights coincide with each other, but they may be arranged eccentrically from each other.

[0080] The polarization conversion element 80 is disposed on the +Y side of the second lens array 76 and overlaps with the second lens array 76 in the X and Z directions. The polarization conversion element 80 is disposed on the optical path of the white light WL emitted from the second lens array 76 to the +Y side along the Y direction and the optical axis AX2. The polarization conversion element 80 converts the polarization direction of the white light WL emitted from the second lens array 76. Specifically, the polarization conversion element 80 converts a partial beam of the white light WL emitted from the second lens array 76 into linearly polarized light.

[0081] The polarization conversion element 80 has a polarization separation layer, a reflection layer, and a phase difference layer (not shown). The polarization separation layer transmits one linearly polarized component of the polarized components contained in the white light WL emitted from the second lens array 76, and reflects the other linearly polarized component in a direction perpendicular to the optical axis AX2. The reflection layer reflects the other linearly polarized component reflected by the polarization separation layer in a direction parallel to the optical axis AX2. The phase difference layer converts the other linearly polarized component reflected by the reflection layer into one linearly polarized component.

[0082] The superimposing lens 82 is disposed on the +Y side of the polarization conversion element 80, and overlaps with the polarization conversion element 80 in the X and Z directions. The superimposing lens 82 is, for example, a biconvex lens having convex surfaces on both the -Y and +Y sides. Note that the superimposing lens 82 may be a plano-convex lens, a meniscus lens, an aspherical lens, a free-form lens, or the like, other than a biconvex lens.

[0083] The first lens array 71, the second lens array 76, and the superimposing lens 82 constitute an integrator optical system. The integrator optical system homogenizes the light intensity distribution of the yellow light YL emitted from the light source 20 and the light intensity distribution of the blue light BL emitted from the light source 40 in a plane perpendicular to the optical axis of incidence on each of the light modulation devices 400B, 400G, and 400R, which are the illuminated areas, and functions as a uniform illumination optical system.

[0084] The white light WL emitted from the superimposing lens 82 travels along the optical axis AX2 toward the +Y side and enters the color separation optical system 200 shown in FIG.

[0085] The control device 120 is electrically connected to the light-receiving sensor 90 and receives, via wire or wireless, the electrical signal output from the light-receiving sensor 90. The control device 120 adjusts the voltage or current supplied to the light-emitting element 50 of the light source 40 and the voltage or current supplied to the plurality of light-emitting elements 10 of the light source 20 according to the strength and relative relationship of the electrical signal output from the light-receiving sensor 90.

[0086] Specifically, the control device 120 receives an electrical signal SB related to the light intensity or light amount of the blue light BL incident on the detection unit 91 of the light-receiving sensor 90, and an electrical signal SY related to the light intensity or light amount of the yellow light YL incident on the detection units 92 and 93 of the light-receiving sensor 90. The control device 120 supplies, to the light-emitting element 50, an electrical signal S1 related to the voltage or current that will achieve the desired light intensity or light amount of the blue light BL. The control device 120 supplies, to the multiple light-emitting elements 10, an electrical signal S1 related to the voltage or current that will achieve the desired light intensity or light amount of the yellow light YL.

[0087] For example, when the intensity of the electric signal SB is less than a predetermined value, the control device 120 increases the intensity of the electric signal S1 to increase the voltage or current supplied to the light-emitting element 50 of the light source 40. When the intensity of the electric signal SB is greater than another predetermined value, the control device 120 decreases the intensity of the electric signal S1 to decrease the voltage or current supplied to the light-emitting element 50 of the light source 40. Similarly, when the intensity of the electric signal SY is less than a predetermined value, the control device 120 increases the intensity of the electric signal S2 to increase the voltage or current supplied to the light-emitting element 10 of the light source 20. When the intensity of the electric signal SY is greater than another predetermined value, the control device 120 decreases the intensity of the electric signal S2 to decrease the voltage or current supplied to the light-emitting element 10 of the light source 20. The range of predetermined values ​​of the intensity of the electrical signal SB related to the blue light BL and the range of predetermined values ​​of the intensity of the electrical signal SY related to the yellow light YL are set in accordance with the color balance of the white light WL, i.e., the illumination light, and the desired color balance required for the image projected from the projection optical system 600 of the projector 1000.

[0088] The spectrum of the yellow light YL emitted from the light source 20 changes depending on the usage time and usage environment of the lighting device 100. The yellow light YL includes green light GL in a green wavelength band included in the yellow wavelength band, and red light RL in a red wavelength band included in the yellow wavelength band but different from the green wavelength band. The green wavelength band corresponds to the third wavelength band. The green light GL corresponds to the third light. The red wavelength band corresponds to the fourth wavelength band. The red light RL corresponds to the fourth light.

[0089] FIG. 7 is a schematic diagram of the spectrum of yellow light YL emitted from the light source 20. For example, as shown in FIG. 7, there are cases where, of the green light GL and red light RL contained in the yellow light YL, only the spectrum of the green light GL changes within the measurement range, while the spectrum of the red light RL remains almost unchanged within the measurement range. The change in the spectrum of the green light GL is detected as an integral value by the detection unit 92 of the light-receiving sensor 90. As described above, the light source 20 uses multiple light-emitting elements 10 composed of LEDs arranged along the X direction. Therefore, the spectrum of the yellow light YL emitted from the light source 20 is more likely to change over time and with the usage environment than a light source of yellow light YL that has a fixed or wheel-type wavelength conversion element that uses a laser diode (LD) as the light source of excitation light.

[0090] In controlling the color balance of the illumination light of the lighting device 100 by the control device 120, the ratio of the light intensity or light quantity of the blue light BL emitted from the light emitting element 50 of the light source 40 to the light intensity or light quantity of the green light GL emitted from the light source 20 to the light intensity or light quantity of the red light RL is maintained within a certain range. For example, in conventional color balance control of illumination light, the integral of the light output over the measurement range of the yellow light YL, i.e., the yellow light integral, is estimated from the red light integral, and the estimated yellow light integral and the measured blue light integral are sometimes used. In this case, if the spectrum of the yellow light YL changes in a complex manner, as illustrated in FIG. 7, an error may occur in the estimated yellow light integral, resulting in illumination light with an incorrect color balance, i.e., an unexpected color balance, being emitted from the lighting device. In contrast, in the lighting device 100 of this embodiment, the green light integral and the red light integral are determined separately by the detectors 92 and 93. As a result, the color balance of the white light WL, i.e., the illumination light, emitted from the superimposing lens 82 located downstream can be accurately adjusted.

[0091] The control device 120 is, for example, a computer or a tablet terminal, and is configured with a processor having a built-in program for performing the above-mentioned processing. The control device 120 may further have a function of outputting an electrical signal related to an image to be projected to each of the light modulation devices 400B, 400G, and 400R of the projector 1000.

[0092] The lighting device 100 of the first embodiment described above includes a light source (first light source) 40, a light source (second light source) 20, a color combining element 60, and a light-receiving sensor 90. The light source 40 emits blue light (first light) BL in a blue wavelength band (first wavelength band). The light source 20 emits yellow light (second light) YL in a yellow wavelength band (second wavelength band) different from the blue wavelength band. The color combining element 60 has a reflective surface (first surface) 60a disposed on the +Y side and a reflective surface (second surface) 60b disposed on the -Y side different from the reflective surface 60a. The light-receiving sensor 90 receives at least a portion of the yellow light YL and at least a portion of the blue light BL. The color combining element 60 has a substrate 62 and a reflective film 64 made of a dielectric multilayer film stacked on the substrate. The transmittance of the reflective film 64 for blue light BL in the blue wavelength band is greater than the reflectance of the blue light BL in the reflective film 64. The reflectance of the reflective film 64 for blue light BL is greater than 0%. The transmittance of the reflective film 64 for yellow light YL in the yellow wavelength band is less than the reflectance of the yellow light YL in the reflective film 64. The transmittance and reflectance of the blue light BL in the reflective film 64 are greater than 0%. In the lighting device 100 of the first embodiment, the blue light BL emitted from the light source 40 is incident on the reflective surface 60a. The yellow light YL emitted from the light source 20 is incident on the reflective surface 60b. The light receiving sensor 90 receives the blue light (light) BL reflected by the reflective surface 60a out of the blue light BL incident on the color combining element 60, and the yellow light (light) YL transmitted through the reflective surface 60b of the color combining element 60 out of the yellow light YL.

[0093] According to the lighting device 100 of the first embodiment, it is not necessary to arrange the light-receiving sensors 90 corresponding to the blue light BL and the yellow light YL separately, which enables the lighting device 100 to be made smaller, configured simply, and cost-effective. Furthermore, with the lighting device 100 of the first embodiment, it is not necessary to arrange a reflecting element or a light-guiding element that guides a portion of the illumination light to the light-receiving sensor 90 on the optical path of the white light WL, i.e., the illumination light, emitted from the superimposing lens 82, which is arranged at the rearmost stage on the optical path of the colored light in the lighting device 100. Therefore, according to the lighting device 100 of the first embodiment, it is possible to suppress the occurrence of shadows on the illumination light that would occur if a reflecting element or a light-guiding element were arranged.

[0094] The lighting device 100 of the first embodiment further includes a control device 120 that controls the color balance of white light (light) WL, which is a composite light including blue light BL reflected by the reflective film 64 and yellow light YL transmitted by the reflective film 64. The control device 120 is connected to the light-receiving sensor 90, and receives an electrical signal related to the intensity of the blue light BL and an electrical signal related to the intensity of the yellow light YL output from the light-receiving sensor 90.

[0095] According to the lighting device 100 of the first embodiment, the color balance of the white light WL, which is the combined light, i.e., the illumination light, can be controlled according to the detection results of the light receiving sensor 90 for the intensities of the blue light BL and the yellow light YL.

[0096] In the lighting device 100 of the first embodiment, the blue light BL incident on the reflecting surface 60a of the color combining element 60 and the yellow light YL incident on the reflecting surface 60b are randomly polarized light. The reflecting film 64 is a YDM (dichroic mirror).

[0097] According to the lighting device 100 of the first embodiment, the white light WL and illumination light emitted from the lighting device 100 are colored lights obtained by combining blue light BL and yellow light YL, and are randomly polarized, so that interference noise caused by the illumination light can be reduced.

[0098] In the lighting device 100 of the first embodiment, the light source 40 includes an LED as the light emitting element 50. The light source 20 includes an LED as the light emitting element .

[0099] According to the lighting device 100 of the first embodiment, randomly polarized light can be easily generated as the blue light BL and the yellow light YL.

[0100] In the lighting device 100 of the first embodiment, the reflectance of the reflective film 64 in the blue wavelength band is 0.01% or more and 10.0% or less, and the transmittance of the reflective film 64 in the yellow wavelength band is 0.01% or more and 10.0% or less.

[0101] According to the lighting device 100 of the first embodiment, the amount of white light WL emitted from the lighting device 100, that is, the amount of illumination light, can be ensured, and the light receiving sensor 90 can acquire information about the amount of blue light BL and yellow light YL.

[0102] In the lighting device 100 of the first embodiment, the light source 20 includes a light-emitting element 10 and a wavelength conversion member 22. The light-emitting element 10 emits excitation light EL in a blue wavelength band toward the wavelength conversion member 22. The wavelength conversion member 22 contains a phosphor and converts the excitation light EL into fluorescence FL, which is yellow light YL in a yellow wavelength band. The wavelength conversion member 22 has an end face (first end face) 22c and an end face (second end face) 22d located opposite each other in the X direction (longitudinal direction), and a side face connecting the end faces 22c and 22d along the X direction. The end face 22c is the end face on the -X side of the wavelength conversion member 22. The end face 22d is the end face on the +XZ side of the wavelength conversion member 22. The end face 22d is located closer to the reflecting surface 60b of the color combining element 60 in the X direction than the end face 22c. The yellow light YL is emitted from the end face 22d of the wavelength conversion member 22.

[0103] According to the lighting device 100 of the first embodiment, the thermal load when the excitation light EL is incident on the wavelength conversion member 22 that is long along the X direction can be reduced, and the durability of the light source 20 can be increased.

[0104] In the lighting device 100 of the first embodiment, the light receiving sensor 90 separately receives green light (third light) GL in a green wavelength band (third wavelength band) included in the yellow wavelength band, and red light (fourth light) RL in a red wavelength band (fourth wavelength band) included in the yellow wavelength band but different from the green wavelength band.

[0105] The lighting device 100 of the first embodiment can detect complex fluctuations in the spectrum of at least one of the green light GL and red light RL contained in the yellow light YL emitted from the light source 20. As a result, the color balance and the like of the white light WL emitted from the lighting device 100, i.e., the illumination light, can be controlled with high precision in accordance with the fluctuations in the spectrum of at least one of the green light GL and red light RL.

[0106] In the lighting device 100 of the first embodiment, the light receiving sensor 90 has multiple detection units 91, 92, and 93. The multiple detection units 91, 92, and 93 can detect blue light BL in the blue wavelength band, green light GL in the green wavelength band, and red light RL in the red wavelength band, which are different colors from one another. The multiple detection units 91, 92, and 93 continuously output electrical signals (data) related to the amounts of the blue light BL, green light GL, and red light RL detected by each unit in chronological order.

[0107] In the lighting device 100 of the first embodiment, electrical signals related to the light intensities of multiple colored lights, i.e., the light intensities of blue light BL, green light GL, and red light RL, are continuously output from an interface within the light-receiving sensor 90, which is configured as a single multi-color sensor. The lighting device 100 of the first embodiment eliminates the need for a waiting time when switching between the detection units 91, 92, and 93 in a chronological order, thereby shortening the transfer time of the electrical signals related to the light intensities of the colored lights. As a result, information on the light intensity ratio between the blue light BL, green light GL, and red light RL of the illumination light in the lighting device 100 can be obtained more quickly and accurately than in conventional lighting devices.

[0108] Although not shown, as a modified example of the illumination device 100 of the first embodiment, the positions of the light source 40 and the light source 20 may be interchanged. That is, the light source 40 may emit blue light BL toward the +X side along the X direction and the optical axis AX1. The light source 20 may emit yellow light YL toward the +Y side along the Y direction and the optical axis AX2. In such an arrangement, the light source 20 corresponds to the first light source, the yellow light YL corresponds to the first light, and the yellow wavelength band corresponds to the first wavelength band. The light source 40 corresponds to the second light source, the blue light BL corresponds to the second light, and the blue wavelength band corresponds to the second wavelength band. Furthermore, the +Y side surface of the reflective film 64 of the color combining element 60 forms the reflective surface 60a and corresponds to the first surface. The -Y side surface of the reflective film 64 of the color combining element 60 forms the reflective surface 60b and corresponds to the second surface. Even with such an apparatus configuration, the same effects as those of the illumination device 100 of the first embodiment can be obtained.

[0109] The projector 1000 of the first embodiment includes the above-described illumination device 100, light modulation devices 400B, 400G, and 400R, and a projection optical system 600. The light modulation devices 400B, 400G, and 400R modulate blue light (colored light) BL, green light (colored light) GL, and red light (colored light) RL emitted from the illumination device 100 according to image information, and emit blue image light, green image light, and red image light. The projection optical system 600 projects the blue image light, green image light, and red image light emitted from the light modulation devices 400B, 400G, and 400R onto a screen SCR.

[0110] According to the projector 1000 of the first embodiment, it is possible to provide a projector including the illumination device 100, which can be configured more compactly and simply than conventional illumination devices. Furthermore, according to the projector 1000 of the first embodiment, it is possible to acquire with high accuracy information on the intensity and light amount of each of the blue light BL and yellow light YL contained in the white light WL emitted from the illumination device 100, i.e., the illumination light.

[0111] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to Fig. 8. In the second embodiment, the content common to the first embodiment will be omitted, and only the content different from the first embodiment will be described. Among the components of the projector and lighting device 102 of the second embodiment, the components common to the projector 1000 and lighting device 100 of the first embodiment will be assigned the same reference numerals as the common components of the projector 1000 and lighting device 100, and detailed description thereof will be omitted.

[0112] Although not shown, the projector of the second embodiment is equipped with the lighting device 102 of the second embodiment instead of the lighting device 100 of the first embodiment, and further has the same configuration as the projector 1000 of the first embodiment other than the lighting device 100.

[0113] Fig. 8 is a schematic diagram showing the configuration of an illumination device 102 according to the second embodiment. As shown in Fig. 8, the illumination device 102 includes light sources 43 and 44, a dichroic mirror 38, a color combining element 60, a light-receiving sensor 90, a first lens array 71, a second lens array 76, a polarization conversion element 80, a superimposing lens 82, and a control device 120. Note that optical lenses 52, 54, and 56 are omitted from Fig. 8.

[0114] The light sources 43 and 44 and the dichroic mirror 38 in the illumination device 102 constitute a light source that emits yellow light YL, similar to the light source 20 in the illumination device 100.

[0115] The light source 43 includes a light-emitting element 14. The light-emitting element 14 is disposed on the -X side of the light source 40 and the optical lenses 32, 34, and 36, and overlaps with the light source 40 in the Y and Z directions. The light source 43 corresponds to a first sub-light source. The light-emitting element 14 emits green light GL from the light-emitting surface 14e toward the +Y side along the Y direction and the optical axis AX3. The optical axis AX3 is parallel to the optical axis AX2 and is located on the -X side of the optical axis AX2.

[0116] The green light GL emitted from the light-emitting element 14 corresponds to the third light. The light-emitting surface 14e of the light-emitting element 14 is an end face extending approximately parallel to the XZ plane on the +Y side of the light-emitting element 14. An optical element such as a lens or a diffuser (not shown) may be disposed on the +Y side of the light-emitting element 14. The green wavelength band of the green light GL emitted from the light-emitting element 14 is included in the yellow wavelength band and is a wavelength band that is a part of the yellow wavelength band, and corresponds to the third wavelength band. The green wavelength band of the green light GL emitted from the light-emitting element 14 is the same green wavelength band as the green light GL that enters the color separation optical system 200 described with reference to FIG. 1. The light-emitting element 14 is, for example, an LED that emits green light GL. The green light GL emitted from the light-emitting element 14 is unpolarized and randomly polarized.

[0117] The number of light-emitting elements 14 is appropriately determined depending on the amount of light of the green light GL required for the projector 1000 and the color balance of the image projected by the projector 1000. When the lighting device 100 has a plurality of light-emitting elements 14, for example, the plurality of light-emitting elements 14 are arranged at intervals from one another within a region (not shown) of the XZ plane centered on the optical axis AX3 of the green light GL.

[0118] 8, the light source 44 includes a light-emitting element 12. The light-emitting element 12 is disposed on the −X side and +Y side of the light-emitting element 14 of the light source 43, is disposed on the optical axis AX1, and overlaps with the light source 43 in the Z direction. The light source 44 corresponds to a second sub-light source. The light-emitting element 12 emits red light RL from the light-emitting surface 12e toward the +X side along the X direction and the optical axis AX1.

[0119] The red light RL emitted from the light-emitting element 12 corresponds to the fourth light. The light-emitting surface 12e of the light-emitting element 12 is an end face extending substantially parallel to the YZ plane on the +X side of the light-emitting element 12. An optical element such as a lens or a diffuser (not shown) may be disposed on the +X side of the light-emitting element 12. The red wavelength band of the red light RL emitted from the light-emitting element 12 is included in the yellow wavelength band, is a wavelength band that is a part of the yellow wavelength band, and is different from the green wavelength band, and corresponds to the fourth wavelength band. The red wavelength band of the red light RL emitted from the light-emitting element 12 is the same red wavelength band as the red light RL incident on the color separation optical system 200 described with reference to FIG. 1. The light-emitting element 12 is, for example, an LED that emits red light RL. The red light RL emitted from the light-emitting element 12 is unpolarized and randomly polarized.

[0120] The number of light-emitting elements 12 is appropriately determined depending on the amount of light of the red light RL required for the projector 1000 and the color balance of the image projected by the projector 1000. When the lighting device 100 has a plurality of light-emitting elements 12, for example, the plurality of light-emitting elements 12 are arranged at intervals from one another within an area (not shown) in the YZ plane centered on the optical axis AX1 of the red light RL.

[0121] The optical axis AX1 of the red light RL emitted from the light-emitting element 12 of the light source 44 is perpendicular to the optical axis AX3 of the green light GL emitted from the light-emitting element 14 of the light source 43 at a predetermined position. The predetermined position is located on the −X side of the position where the optical axes AX1 and AX2 intersect.

[0122] Dichroic mirror 38 is disposed in a region that includes a predetermined position where optical axes AX1 and AX3 intersect, and where red light RL emitted from light source 44 to the +X side along the X direction and green light GL emitted from light source 43 to the +Y side along the Y direction overlap. Dichroic mirror 38 is a green reflective dichroic mirror (GDM), has a reflective surface, and is made of a dielectric multilayer film.

[0123] The reflective surface of dichroic mirror 38 transmits red light RL incident from the -X side along the X direction toward the +X side, and reflects green light GL incident from the -Y side along the Y direction toward the +X side along the X direction. The reflective surface of dichroic mirror 38 moves from the -Y side to the +Y side as it moves from the -X side to the +X side. Dichroic mirror 38 combines the reflected green light GL and the transmitted red light RL to generate yellow light YL.

[0124] In the lighting device 102, instead of the electrical signal S2, the control device 120 supplies to the light-emitting element 14 an electrical signal S3 related to a voltage or current that realizes the light intensity or light amount required for the green light GL, and supplies to the light-emitting element 12 an electrical signal S4 related to a voltage or current that realizes the light intensity or light amount required for the red light RL.

[0125] In the lighting device 102 of the second embodiment described above, the light source (second light source) 20 includes a light source (first sub-light source) 43 and a light source (second sub-light source) 44. The light source 43 emits green light (third light) GL in a green wavelength band (third wavelength band) included in the yellow wavelength band. The light source 44 emits red light (fourth light) RL in a red wavelength band (fourth wavelength band) included in the yellow wavelength band but different from the green wavelength band.

[0126] In the second embodiment of the lighting device 102, three light sources 40, 43, and 44 generate three colors of light consisting of blue light BL, green light GL, and red light RL, thereby expanding the color gamut of the white light WL and illumination light emitted from the superimposing lens 82 located at the subsequent stage.

[0127] The lighting device 102 of the second embodiment provides the same effects as those of the lighting device 100 of the first embodiment due to the common arrangement.

[0128] Although not shown, as a modified example of the illumination device 102 of the second embodiment, the positions of the light source 43 and the light source 44 may be interchanged. That is, the light source 43 may emit green light GL toward the +X side along the X direction and the optical axis AX1. The light source 44 may emit red light RL toward the +Y side along the Y direction and the optical axis AX3. In this arrangement, the reflective surface of the dichroic mirror 38 transmits green light GL incident from the -X side along the X direction to the +X side, and reflects red light RL incident from the -Y side along the Y direction to the +X side along the X direction. The dichroic mirror 38 combines the transmitted red light RL with the reflected red light RL to generate yellow light YL. This arrangement provides the same effects as the illumination device 102 of the second embodiment.

[0129] [Third embodiment] Next, a second embodiment of the present invention will be described with reference to Fig. 9. In the third embodiment, content common to the first and second embodiments will be omitted, and only content different from the first and second embodiments will be described. Of the components of the projector and lighting device 104 of the third embodiment, components common to the projector 1000 and lighting device 100 of the first embodiment will be assigned the same reference numerals as the components of the common projector 1000 and lighting device 100, and detailed description thereof will be omitted.

[0130] Although not shown, the projector of the third embodiment is equipped with the illumination device 104 of the third embodiment instead of the illumination device 100 of the first embodiment, and further has the same configuration as the projector 1000 of the first embodiment other than the illumination device 100.

[0131] Fig. 9 is a schematic diagram showing the configuration of an illumination device 104 of the third embodiment. As shown in Fig. 9, the illumination device 104, like the illumination device 102 of the second embodiment, includes light sources 43 and 44, a dichroic mirror 38, a color combining element 60, a light-receiving sensor 90, a first lens array 71, a second lens array 76, a polarization conversion element 80, a superimposing lens 82, and a control device 120. Note that the optical lenses 52, 54, and 56 are also omitted from Fig. 9.

[0132] The light source 40 includes a light-emitting element 58 instead of the light-emitting element 50. The light-emitting element 58 emits blue light BL from a light-emitting surface 58e toward the +X side along the Y direction and the optical axis AX2. The light-emitting element 58 is, for example, an LD that emits blue light BL. The blue light BL emitted from the light-emitting element 58 is linearly polarized light, for example, P-polarized light. The polarization direction of the blue light BL is parallel to the X direction.

[0133] The light source 43 includes a light-emitting element 16 instead of the light-emitting element 14. The light-emitting element 16 emits green light GL from its light-emitting surface 16e toward the +Y side along the Y direction and optical axis AX3. The light-emitting element 16 is an LD that emits green light GL. The light source 44 includes a light-emitting element 18 instead of the light-emitting element 12. The light-emitting element 18 emits red light RL from its light-emitting surface 18e toward the +X side along the X direction and optical axis AX1. The light-emitting element 18 is an LD that emits red light RL. The green light GL emitted from the light-emitting element 16 and the red light RL emitted from the light-emitting element 18 are linearly polarized light. The yellow light YL combined by the dichroic mirror 38 is, for example, S-polarized light. The polarization direction of the blue light BL is parallel to the X direction.

[0134] The color combining element 60 is, for example, a cube-shaped polarizing beam splitter, and has two rectangular prisms 62A and 62B and a reflective film 64. The reflective film 64 is disposed on the joint surface between the inclined faces of the two rectangular prisms 62A and 62B. The reflective film 64 is disposed on the inclined face of the rectangular prism 62A, and the rectangular prism 62A functions as a substrate in the color combining element 60.

[0135] The rectangular prisms 62A and 62B are formed of a material that transmits light in the visible wavelength band and is translucent for light in the visible wavelength band. When viewed along the Z direction, the slopes of the rectangular prisms 62A and 62B are inclined at 45° with respect to the Y and X directions and at 45° with respect to the YZ and XZ planes. The slopes of the rectangular prisms 62A and 62B move from the -Y side to the +Y side as they move from the -X side to the +X side.

[0136] The X-direction sizes of the rectangular prisms 62A, 62B and the reflective film 64 are approximately the same as the X-direction size of the blue light BL incident on the reflective film 64 through the rectangular prism 62A from the -Y side, with an appropriate margin provided around the periphery. Similarly, the Y-direction sizes of the rectangular prisms 62A, 62B and the reflective film 64 are approximately the same as the Y-direction size of the yellow light YL incident on the reflective film 64 through the rectangular prism 62B from the -X side, with an appropriate margin provided around the periphery. The Z-direction sizes of the rectangular prisms 62A, 62B and the reflective film 64 are approximately the larger of the Z-direction size of the yellow light YL incident on the reflective film 64 through the rectangular prism 62B from the -X side and the Z-direction size of the blue light BL incident on the reflective film 64 through the rectangular prism 62A from the -Y side, with an appropriate margin provided around the periphery.

[0137] The white light WL, i.e., illumination light, combined by the color combining element 60 includes P-polarized blue light BL and S-polarized yellow light YL, and is incident as unpolarized or randomly polarized light on the first lens array 71. As with the illumination device 100 of the first embodiment and the illumination device 102 of the second embodiment, the white light WL is converted into linearly polarized light by the polarization conversion element 80 of the illumination device 104 and is emitted from the superimposing lens 82.

[0138] In the lighting device 104 of the third embodiment described above, the blue light BL incident on the reflective surface 60a of the color combining element 60 and the yellow light YL incident on the reflective surface 60b are linearly polarized light. The color combining element 60 is configured, for example, by a cube-type polarizing beam splitter. The reflective film 64 of the color combining element 60 is configured by a dielectric multilayer film disposed between the two rectangular prisms 62A and 62B of the cube-type polarizing beam splitter.

[0139] In the illumination device 104 of the third embodiment, the intensity of the colored light incident on each of the detection sections 91, 92, and 93 of the light receiving sensor 90 can be easily adjusted depending on the amount of shift in the polarization axes of blue light BL, green light GL, and red light RL, which are linearly polarized light relative to the directions of the S-polarized and P-polarized axes in the polarizing beam splitter.

[0140] The lighting device 104 of the third embodiment can achieve the same effects as those achieved by the arrangement common to the lighting device 100 of the first embodiment and the lighting device 102 of the second embodiment. Furthermore, the lighting device 104 of the third embodiment may also employ the modified examples described for the lighting device 102 of the second embodiment.

[0141] Although a cube-type polarizing beam splitter has been exemplified as the color combining element 60 in the lighting device 104 of the third embodiment, a plate-type polarizing beam splitter having a substrate and a reflective film 64 may be used instead of the cube-type polarizing beam splitter.

[0142] Although not shown, the polarizing beam splitter may use a nonlinear optical crystal. The color combining element 60 in the illumination device 104 of the third embodiment may be, for example, a prism made of a birefringent material or a combination of a Glan-Taylor prism and a wedge prism. Even when such a configuration is used, the intensity of the colored light incident on each of the detection units 91, 92, and 93 of the light receiving sensor 90 can be easily adjusted depending on the amount of deviation of the polarization axis of the colored light from the axes of S-polarized light and P-polarized light in the polarizing beam splitter and the color combining element 60.

[0143] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as set forth in the claims. Furthermore, the configurations of multiple embodiments and modifications of the embodiments may be combined as appropriate.

[0144] Summary of this disclosure A summary of this disclosure is provided below. (Supplementary Note 1) A color combining device including a first light source that emits first light in a first wavelength band, a second light source that emits second light in a second wavelength band different from the first wavelength band, a color combining element having a first surface and a second surface different from the first surface, and a light receiving sensor that receives the first light and the second light, wherein the color combining element includes a substrate and a light receiving element stacked on the substrate. reflective film the reflecting film has a transmittance in the first wavelength band that is greater than a reflectance and a reflectance in the first wavelength band that is greater than 0%, the reflecting film has a transmittance in the second wavelength band that is less than the reflectance and a transmittance in the second wavelength band that is greater than 0%, the first light is incident on the first surface, the second light is incident on the second surface, and the light-receiving sensor receives light of the first light reflected by the first surface and light of the second light transmitted by the second surface.

[0145] The configuration of Supplementary Note 1 makes it possible to miniaturize the lighting device, simplify the configuration of the lighting device, and reduce overall costs including manufacturing and installation costs. In addition, it is possible to suppress the occurrence of shadows in the illumination light that occur when a reflecting element or a light-guiding element is disposed as in conventional lighting devices.

[0146] (Appendix 2) The lighting device of Appendix 1, further comprising a control device for controlling the color balance of a combined light including the first light reflected by the reflective film and the second light transmitted by the reflective film.

[0147] The configuration of Supplementary Note 2 makes it possible to control the color balance of the illumination light, which is the combined light emitted from the lighting device, according to the detection results of the intensities of the first light and the second light by the light receiving sensor.

[0148] (Supplementary Note 3) The illumination device according to Supplementary Note 1 or Supplementary Note 2, wherein the first light incident on the first surface and the second light incident on the second surface are randomly polarized light, and the reflective film is a dichroic mirror.

[0149] The configuration of Supplementary Note 3 can reduce interference noise caused by illumination light emitted from the lighting device.

[0150] (Supplementary Note 4) The lighting device of any one of Supplementary Notes 1 to 3, wherein the first light source and the second light source include LEDs.

[0151] The configuration of Supplementary Note 4 makes it easy to generate the first light and the second light of random polarization.

[0152] (Appendix 5) The lighting device according to any one of Appendices 1 to 4, wherein the reflectance of the reflective film in the first wavelength band is 0.01% or more and 10.00% or less, and the transmittance of the reflective film in the second wavelength band is 0.01% or more and 10.00% or less.

[0153] The configuration of Supplementary Note 5 ensures the amount of illumination light emitted from the lighting device, and also makes it possible to obtain information about the intensity or amount of the first light and the second light by the light receiving sensor.

[0154] (Supplementary Note 6) The lighting device of any one of Supplementary Notes 1 to 5, wherein the second light source comprises a light-emitting element that emits excitation light, and a wavelength conversion member that includes a phosphor and converts the excitation light into the second light, the wavelength conversion member having a first end face and a second end face located opposite each other in a longitudinal direction, and a side face that connects the first end face and the second end face along the longitudinal direction, the second end face being disposed at a position closer to the second face than the first end face in the longitudinal direction, and the second light being emitted from the second end face.

[0155] The configuration of Supplementary Note 6 can reduce the thermal load when excitation light is incident on a long wavelength conversion member, and can increase the durability of the light source 20.

[0156] (Supplementary Note 7) The lighting device of Supplementary Note 6, wherein the light receiving sensor receives third light in a third wavelength band included in the second wavelength band and fourth light in a fourth wavelength band included in the second wavelength band and different from the third wavelength band.

[0157] The configuration of Supplementary Note 7 makes it possible to detect complex fluctuations in the spectrum of at least one of the colored light of the third light and the fourth light contained in the second light emitted from the second light source. As a result, it is possible to control the color balance and the like of the illumination light emitted from the lighting device with high precision in accordance with the fluctuations in the spectrum of at least one of the colored light of the third light and the fourth light.

[0158] (Appendix 8) The lighting device according to any one of Appendices 1 to 7, wherein the light receiving sensor has a plurality of detection units capable of detecting light of wavelength bands of different colors, and the plurality of detection units output data on the amount of colored light detected continuously in time series.

[0159] The configuration of Supplementary Note 8 eliminates the need for waiting time when switching between multiple detection units in time series, thereby shortening the transfer time of electrical signals related to the intensity or amount of colored light. As a result, information on the light amount ratio of colored light contained in the illumination light of the illumination device can be obtained more quickly and accurately than with conventional illumination devices.

[0160] (Appendix 9) The lighting device of any one of Appendices 1 to 8, wherein the second light source includes a first sub-light source that emits third light in a third wavelength band included in the second wavelength band, and a second sub-light source that emits fourth light in a fourth wavelength band included in the second wavelength band and different from the third wavelength band.

[0161] With the configuration of Appendix 9, the first light source, the first sub-light source, and the second sub-light source individually generate three colors of light to be combined into illumination light, thereby expanding the color gamut of the illumination light emitted from the lighting device compared to when only the first light source and the second light source are used.

[0162] (Appendix 10) A projector comprising: an illumination device according to any one of appendices 1 to 9; a light modulation device that modulates color light emitted from the illumination device in accordance with image information; and a projection optical system that projects the image light emitted from the light modulation device.

[0163] The configuration of Supplementary Note 10 makes it possible to provide a projector equipped with an illumination device that is smaller and can be configured more simply than conventional illumination devices. [Explanation of symbols]

[0164] 20...light source (second light source), 40...light source (first light source), 60...color combining element, 62...substrate, 64...reflective film, 90...light receiving sensor, 100...illumination device, 120...control device, 1000...projector, BL...blue light (first light), YL...yellow light (second light).

Claims

1. a first light source that emits first light in a first wavelength band; a second light source that emits second light in a second wavelength band different from the first wavelength band; a color combining element having a first surface and a second surface different from the first surface; a light-receiving sensor that receives the first light and the second light; Equipped with The color combining element is A substrate; a reflective film laminated on the substrate; and the transmittance of the reflective film in the first wavelength band is greater than the reflectance, and the reflectance in the first wavelength band is greater than 0%, the transmittance of the reflective film in the second wavelength band is smaller than the reflectance, and the transmittance of the reflective film in the second wavelength band is greater than 0%; the first light is incident on the first surface, the second light is incident on the second surface, the light-receiving sensor receives the first light reflected by the first surface and the second light transmitted by the second surface; Lighting equipment.

2. a control device for controlling a color balance of a combined light including the first light reflected by the reflective film and the second light transmitted by the reflective film, The lighting device according to claim 1 .

3. the first light incident on the first surface and the second light incident on the second surface are randomly polarized light; The reflective film is a dichroic mirror.

3. The lighting device according to claim 1 or 2.

4. the first light source and the second light source comprise light emitting diodes; 3. The lighting device according to claim 1 or 2.

5. the reflectance of the reflective film in the first wavelength band is 0.01% or more and 10.00% or less, the transmittance of the reflective film in the second wavelength band is 0.01% or more and 10.00% or less; 3. The lighting device according to claim 1 or 2.

6. The second light source is a light emitting element that emits excitation light; a wavelength conversion member that includes a phosphor and converts the excitation light into the second light; and the wavelength conversion member has a first end surface and a second end surface located opposite to each other in a longitudinal direction, and a side surface connecting the first end surface and the second end surface along the longitudinal direction, the second end surface is disposed at a position closer to the second surface than the first end surface in the longitudinal direction, The second light is emitted from the second end surface.

3. The lighting device according to claim 1 or 2.

7. the light receiving sensor receives third light in a third wavelength band included in the second wavelength band and fourth light in a fourth wavelength band included in the second wavelength band and different from the third wavelength band; 7. The lighting device according to claim 6.

8. the light receiving sensor has a plurality of detection units capable of detecting light in wavelength bands of different colors, the plurality of detection units output data relating to the light amounts of the colored lights detected continuously in time series; 3. The lighting device according to claim 1 or 2.

9. the second light source includes a first sub-light source that emits third light in a third wavelength band that is included in the second wavelength band, and a second sub-light source that emits fourth light in a fourth wavelength band that is included in the second wavelength band and different from the third wavelength band; 3. The lighting device according to claim 1 or 2.

10. The lighting device according to claim 1 or 2; a light modulation device that modulates the color light emitted from the illumination device in accordance with image information; a projection optical system that projects image light emitted from the light modulation device; Equipped with projector.

Images