JP6701681B2 - Lighting device and projector - Google Patents

Description

  The present invention relates to a lighting device and a projector.

2. Description of the Related Art Conventionally, there is known a projector that modulates illumination light emitted from a light source device to form an image according to image information, and enlarges and projects the image on a projection surface such as a screen (see, for example, Patent Document 1). ).
The projector described in Patent Document 1 includes an illumination device, a color separation device, a light modulation device, a photosynthesis device, and a projection optical device. Of these, the illumination device includes a solid-state light source device, a condensing optical system, a rotating fluorescent plate, a motor, a collimating optical system, a first lens array, a second lens array, a polarization conversion element, and a superimposing lens. In this illuminating device, the light emitted from the solid-state light source device is condensed by the condensing optical system and is incident on the rotating fluorescent plate rotated by the motor. Then, the light incident on the rotating fluorescent plate is emitted as fluorescence from the rotating fluorescent plate and becomes light collimated by the collimating optical system, and the light is passed through the first lens array and the second lens array to the polarization conversion element. It is incident. This polarization conversion element has a configuration in which a plurality of polarization separation layers and reflection layers are alternately arranged along one direction in a plane orthogonal to the optical axis, and the light whose polarization directions are aligned by the polarization conversion element is superimposed. The light is superimposed by the lens and is emitted as illumination light from the illumination device.

JP, 2011-197212, A

  However, in the illumination device for a projector described in Patent Document 1, the light passing through the first lens array and the second lens array is incident on the polarization conversion element. Therefore, the size of the second lens array and the size of the polarization conversion element are large. And are set to be substantially the same. Therefore, there is a problem that the polarization conversion element becomes large and it is difficult to miniaturize the illumination device. Further, in the polarization conversion element of the projector described in Patent Document 1, the configuration in which the polarization separation layers and the reflection layers are alternately arranged along one direction in the plane orthogonal to the optical axis is adopted as described above. Therefore, there is a problem that the configuration becomes complicated.

  The present invention has an object to solve at least a part of the above-mentioned problems, and an object thereof is to provide a lighting device and a projector which can be simplified in structure and can be downsized.

  An illumination device according to a first aspect of the present invention is a light source device that emits light, a polarization conversion element that aligns the polarization directions of light emitted from the light source device, and a central axis of light that is incident from the polarization conversion element. A homogenizing device for homogenizing illuminance in a plane orthogonal to the polarization conversion element, wherein the polarization conversion element transmits one polarized light of the light emitted from the light source device and reflects the other polarized light. A polarized light separating layer, and a reflective layer that reflects the other polarized light reflected by the polarized light separating layer in the same direction as the traveling direction of the one polarized light that has passed through the polarized light separating layer; A retardation layer that is disposed on the optical path of one of the one polarized light transmitted through the layer and the other polarized light reflected by the reflective layer and that converts the polarization direction of the polarized light. And the polarization conversion element has one set of the polarization separation layer, the reflection layer, and the retardation layer.

As the light source device, in addition to a laser light source and an LED (Light Emitting Diode), a laser light source that emits excitation light such as blue light or ultraviolet light, an LED, and a phosphor that receives the excitation light and performs wavelength conversion, Therefore, a light source that emits yellow light can be exemplified. Further, as the above-mentioned phosphor, a YAG phosphor can be exemplified.
According to the first aspect, since the pair of polarization conversion elements is arranged between the light source device and the homogenizing device, the size of the polarization conversion element can be reduced as compared with the case where the polarization converting element is arranged in the latter stage of the homogenizing device. it can.
Further, since the polarization conversion element has only one set of the polarization separation layer, the reflection layer, and the retardation layer, the polarization directions of the incident light can be aligned, so that the plurality of polarization separation layers and the retardation layers are orthogonal to the optical axis. The configuration of the polarization conversion element can be simplified as compared with the configuration having a plurality in one direction in the plane.

In the first aspect, in the homogenizing device, a plurality of first lenses are arranged in a plane orthogonal to a central axis of the incident light flux, and the light flux incident by the plurality of first lenses is divided into a plurality of partial light fluxes. A first lens array to be divided, a second lens array in which a plurality of second lenses corresponding to the plurality of first lenses are arranged in the orthogonal plane, and a light emitting side of the second lens array, And a superimposing lens that superimposes the plurality of partial light beams that are divided by the first lens array and are incident through the plurality of second lenses on an illuminated region.
According to the first aspect, the homogenizing device splits the incident light flux, which is incident through the light source device and the polarization conversion element, into the plurality of partial light fluxes by the first lens array, and emits the partial light flux through the second lens array. Since the plurality of partial light fluxes are superimposed on the illuminated area by the superimposing lens, each of the partial light fluxes can be adjusted so as to illuminate the entire illuminated area. Therefore, the light emitted from the lighting device can be made uniform and can be effectively used.
Here, like the illumination device in the projector described in Patent Document 1, after passing through the first lens array and the second lens array, along the polarization separation layer and the reflection layer along one direction in the plane orthogonal to the optical axis. When aligning the polarization directions of light with the plurality of polarization conversion elements arranged alternately, it is necessary to decenter the plurality of first lenses of the first lens array with respect to the second lens array. On the other hand, according to the first aspect, since the polarization conversion element is arranged between the light source device and the homogenizing device, the plurality of first lenses of the first lens array are arranged with respect to the second lens array. Since it is not necessary to decenter it, for example, the first lens array and the second lens array can be formed by the same member. Therefore, the number of parts of the lighting device and the manufacturing cost can be reduced.

In the first aspect, it is preferable that the first lens array includes an afocal lens that is disposed on the light incident side and that expands the beam diameter of the incident light and emits it.
Here, in order to reduce the size, the light source device is provided with a condenser lens, and when a compact lens having a short focal length is adopted as the condenser lens, the condenser lens is used to collect light. When the generated light is directly incident on the homogenizing device, the light source image becomes too large, so that the light cannot be effectively used.
On the other hand, according to the first aspect, since the focal length can be lengthened by the afocal lens and the size of the light source image can be adjusted, the light source image formed on each of the plurality of second lenses of the second lens array. Can be made smaller. Thereby, the utilization efficiency of light in the lighting device can be improved.

According to the first aspect, it is preferable that the afocal lens has a light converging property.
According to the first aspect, since the light incident on the afocal lens can be condensed, the spread of the light emitted from the afocal lens can be reduced, so that the sizes of the first lens array and the second lens array can be reduced. The optical path from the afocal lens to a predetermined irradiation target (for example, a light modulation device if the lighting device is used in a projector) can be shortened. As a result, the light reaching efficiency of the predetermined irradiation target can be improved, and the light emitting efficiency of the light emitted from the light source device can be improved. Therefore, the lighting device can be downsized.

In the first aspect, the afocal lens preferably has an anamorphic lens surface.
According to the first aspect, the spread of the light rays of the light emitted from the afocal lens can be optimized independently in two directions on the plane orthogonal to the optical axis. Therefore, since the optical path can be shortened, the lighting device can be downsized.

In the first aspect, it is preferable that an optical element having an anamorphic lens surface is provided on the light incident side of the first lens array.
According to the first aspect, as in the case where the afocal lens has the anamorphic lens surface, the spread of the light beam of the light emitted from the afocal lens can be optimized independently in two directions. Therefore, since the optical path can be shortened, the lighting device can be downsized.

In the first aspect, it is preferable that a prism having a cylindrical lens surface is provided on the light incident side of the first lens array.
According to the first aspect, the spread of the light rays of the light emitted from the afocal lens can be optimized independently in two directions. Therefore, since the optical path can be shortened, the lighting device can be downsized.

In the first aspect, the light source device includes a light source unit, a condensing lens that condenses the light incident from the light source unit, and a wavelength conversion element that wavelength-converts a part of the light from the condensing lens. A collimator lens for collimating light from the light emitting region of the wavelength conversion element, wherein the aspect ratio of the light emitting region of the wavelength conversion element is equal to each of the plurality of second lenses of the second lens array. It is preferable that the aspect ratio of the shape divided into two in the direction in which the polarization separation layer and the reflection layer are arranged is substantially the same.
According to the first aspect, the light flux emitted from the wavelength conversion element in the light source device is doubled in the direction in which the polarization separation layer and the reflection layer are aligned when passing through the polarization conversion element. The expanded light flux is incident on the second lens array via the first lens array. Therefore, by passing through the polarization conversion element, the light flux from the light source device in the second lens of the second lens array becomes twice the aspect ratio of the light emitting region of the wavelength conversion element, and the second lens array of the second lens array. It is almost the same as the aspect ratio of the lens shape. Therefore, the utilization efficiency of the light emitted from the light source device can be further improved.

In the first aspect, the polarization conversion element has a prism that fixes the polarization separation layer from both sides, and has an air layer between the prism and the reflection layer that are arranged on the reflection layer side. Is preferred.
According to the first aspect, the light transmitted through the prism disposed on the reflective layer side is totally reflected if it exceeds the critical angle at the interface between the prism and the air layer. The light emitted toward the air layer can be incident on the polarization separation layer. Therefore, the utilization efficiency of the light incident on the polarization separation layer can be increased, and the polarization separation function of the polarization conversion element can be improved.

A projector according to a second aspect of the present invention includes the lighting device, a light modulation device that modulates light emitted from the lighting device, and a projection optical device that projects light modulated by the light modulation device. It is preferable to provide.
According to the second aspect, the same effect as that of the illumination device according to the first aspect can be obtained. Further, since the lighting device can be downsized, the projector can also be downsized.

1 is a schematic diagram showing a schematic configuration of a projector according to a first embodiment of the invention. 1 is a schematic diagram showing a schematic configuration of a lighting device of a projector according to the first embodiment. FIG. 3 is a schematic diagram showing a lens configuration between an illumination device and a light modulation device in the projector according to the first embodiment. FIG. 6 is a schematic diagram showing a lens configuration between an illumination device and a light modulation device in a projector according to a second embodiment of the invention. FIG. 9 is a schematic diagram showing a lens configuration between an illumination device and a light modulation device in a projector according to a third embodiment of the invention. The schematic diagram which shows the lens structure between the illuminating device and the light modulator in the projector which concerns on 4th Embodiment of this invention.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
[Schematic configuration of projector]
FIG. 1 is a schematic diagram showing a schematic configuration of the projector 1 according to the first embodiment.
The projector 1 is a display device that modulates a light flux emitted from a light source provided inside to form an image according to image information and projects the image on a projection surface such as the screen SC1 in an enlarged manner.
As shown in FIG. 1, the projector 1 includes an exterior housing 2, an optical unit 3 housed in the exterior housing 2, a controller for controlling the projector 1 and a cooling unit, although not shown. A cooling device that cools the target and a power supply device that supplies power to the electronic components that configure the projector 1 are provided.

[Optical unit configuration]
The optical unit 3 includes an illumination device 31, a color separation device 32, a collimating lens 33, a plurality of light modulation devices 34, a color synthesis device 35, and a projection optical device 36.
The illuminating device 31 emits the illumination light WL. The configuration of the lighting device 31 will be described later.
The color separation device 32 separates the illumination light WL incident from the illumination device 31 into three color lights of red light LR, green light LG, and blue light LB. The color separation device 32 includes dichroic mirrors 321, 322, total reflection mirrors 323, 324, 325 and relay lenses 326, 327.

The dichroic mirror 321 separates the illumination light WL from the illumination device 31 into blue light LB and yellow light LY including other colored light (green light LG and red light LR). The dichroic mirror 321 reflects the blue light LB and transmits the yellow light LY including the green light LG and the red light LR.
The dichroic mirror 322 separates the yellow light LY, which is one of the lights separated by the dichroic mirror 321, into a green light LG and a red light LR. Specifically, the dichroic mirror 322 reflects the green light LG and transmits the red light LR.

The total reflection mirror 323 is arranged in the optical path of the blue light LB, and reflects the blue light LB reflected by the dichroic mirror 321 toward the light modulator 34 (34B). On the other hand, the total reflection mirrors 324 and 325 are arranged in the optical path of the red light LR and reflect the red light LR transmitted through the dichroic mirror 322 toward the light modulator 34 (34R). The green light LG is reflected by the dichroic mirror 322 toward the light modulator 34 (34G).
The relay lenses 326 and 327 are arranged downstream of the dichroic mirror 322 in the optical path of the red light LR. The relay lenses 326 and 327 have a function of compensating the optical loss of the red light LR due to the optical path length of the red light LR being longer than the optical path lengths of the blue light LB and the green light LG.

  The collimating lens 33 collimates the light incident on the light modulator 34 described later. The collimating lenses for the red, green, and blue lights are 33R, 33G, and 33B, respectively. Further, the light modulators for red, green, and blue lights are 34R, 34G, and 34B, respectively.

The plurality of light modulators 34 (34R, 34G, 34B) are separated by the dichroic mirror 321 and the dichroic mirror 322, and modulate the respective incident color lights LR, LG, LB to generate a color image according to image information. Form. These light modulators 34 are composed of liquid crystal panels that modulate incident light.
Further, an incident side polarization plate 341 and an emission side polarization plate 342 are arranged on the incident side and the emission side of the light modulators 34R, 34G, 34B, respectively. The incident-side polarization plates for the red, green, and blue color lights are 341R, 341G, and 341B, and the emission-side polarization plates for the red, green, and blue color lights are 342R, 342G, and 342B, respectively. ..

Image light from the light modulators 34R, 34G, and 34B is incident on the color synthesizer 35. The color combining device 35 combines the image lights corresponding to the respective color lights LR, LG, and LB, and emits the combined image lights toward the projection optical device 36. In this embodiment, the color synthesizing device 35 is composed of a cross dichroic prism.
The projection optical device 36 projects the image light combined by the color combining device 35 onto the projection surface such as the screen SC1. With such a configuration, the enlarged image is projected on the screen SC1.

[Configuration of lighting device]
FIG. 2 is a schematic diagram showing the configuration of the illumination device 31 in the projector 1 of the present embodiment.
The illumination device 31 emits the illumination light WL toward the color separation device 32 as described above. As shown in FIG. 2, the lighting device 31 includes a light source device 31A, a polarization conversion element 4, an afocal device 31B, and a homogenizing device 31C.

[Configuration of light source device]
The light source device 31A emits light to the polarization conversion element 4. The light source device 31A includes a light source unit 311, a condenser lens 312, a wavelength conversion element 313, and a collimator optical system 314.
The light source unit 311 includes an array light source 311A and a collimator lens group 311B. The array light source 311A is composed of a plurality of semiconductor lasers 3111. Specifically, the array light source 311A is formed by arranging a plurality of semiconductor lasers 3111 in an array in one plane orthogonal to the light flux emitted from the array light source 311A.

  The semiconductor laser 3111 forming the array light source 311A emits excitation light (blue light BL) having a peak wavelength in the wavelength region of 440 to 480 nm, for example. The blue light BL emitted from the semiconductor laser 3111 is coherent linearly polarized light in which s-polarized light and p-polarized light are mixed, and is emitted toward the condenser lens 312. Then, the blue light BL emitted from the array light source 311A is incident on the collimator lens group 311B.

The collimator lens group 311B converts the blue light BL emitted from the array light source 311A into parallel light. The collimator lens group 311B is composed of, for example, a plurality of collimator lenses 3112 arranged in an array corresponding to each semiconductor laser 3111. The blue light BL converted into parallel light by passing through the collimator lens group 311B is incident on the condenser lens 312.
The condenser lens 312 condenses the incident blue light BL. The blue light BL condensed by the condenser lens 312 is incident on the phosphor layer 3132 via the base material 3131 of the wavelength conversion element 313.

The wavelength conversion element 313 includes a base material 3131, a phosphor layer 3132, and a motor 3133. The base material 3131 is made of a translucent member that transmits incident light, and is formed into a substantially disc shape. A phosphor layer 3132 is formed in a donut shape on the disk-shaped base material 3131.
The phosphor layer 3132 is, for example, a wavelength conversion element including a YAG phosphor, and part of the blue light BL incident on the phosphor layer 3132 is emitted as the fluorescence YL including the red light LR and the green light LG. It In addition, part of the blue light BL passes through the phosphor layer 3132 as the blue light BL without being converted into the fluorescence YL.
The motor 3133 is attached to the base material 3131, and the base material 3131 is rotated by driving the motor 3133. As a result, the temperature rise of the phosphor layer 3132 is reduced.

  The collimator optical system 314 includes a toric lens 3141 and a collimator lens 3142. Of these, the toric lens 3141 adjusts the shape of the incident light to be substantially the same as the light incident surface of the light modulator 34. The collimator lens 3142 collimates the incident light. The fluorescence YL and the blue light BL that have passed through the phosphor layer 3132 enter the polarization conversion element 4 via the toric lens 3141 and the collimator lens 3142.

[Configuration of polarization conversion element]
The polarization conversion element 4 has a function of aligning the polarization directions of incident light. As shown in FIG. 2, the polarization conversion element 4 includes a polarization beam splitter 41, a retardation plate 42, and a reflection member 43. The polarization beam splitter 41, the phase difference plate 42, and the reflection member 43 are integrated by a fixing member or the like (not shown). That is, the polarization conversion element 4 is a set of devices in which the polarization beam splitter 41, the phase difference plate 42, and the reflection member 43 are integrated.
Of these, the polarization beam splitter 41 is a so-called prism type polarization beam splitter, and transmits one polarized light of p-polarized light and s-polarized light and reflects the other polarized light. The polarization beam splitter 41 includes prisms 411 and 412 and a polarization separation layer 413. Each of the prisms 411 and 412 is formed in a substantially triangular prism shape, has an inclined surface that makes an angle of 45° with the illumination optical axis Ax, and forms an angle of 45° with the illumination optical axis Ax. There is.

  The polarization separation layer 413 is provided on the inclined surfaces of the prisms 411 and 412. In other words, the polarization separation layer 413 has both surfaces fixed by the prisms 411 and 412. The polarization separation layer 413 has a polarization separation function of separating the fluorescence YL and the blue light BL that have entered the polarization separation layer 413 into an s polarization component and a p polarization component. The polarization separation layer 413 reflects the s-polarized component of the fluorescence YL and the blue light BL toward the reflecting member 43, and transmits the p-polarized component of the fluorescence YL and the blue light BL.

  The retardation plate 42 corresponds to the retardation layer of the present invention and has a function of converting the fluorescence YL of the p polarization component and the blue light BL transmitted through the polarization separation layer 413 into the light of the s polarization component. The retardation plate 42 is fixed to the surface (light emission surface) of the prism 412 of the polarization beam splitter 41 in the direction along the illumination optical axis Ax. As a result, the fluorescence YL of the p-polarized component and the blue light BL that have entered the retardation plate 42 via the prism 411 of the polarization beam splitter 41 are emitted toward the reflection member 43 as light of the s-polarized component.

The reflection member 43 corresponds to the reflection layer of the present invention, has a function of reflecting incident light, and is configured by a rectangular plate-shaped total reflection mirror in the present embodiment. The reflecting member 43 is arranged with an air layer between the polarizing beam splitter 41 and the reflecting member 43. As a result, the s-polarized component fluorescence YL and the blue light BL are incident on the reflecting member 43, reflected by the reflecting member 43, and emitted toward the afocal device 31B.
That is, the fluorescence YL of the s-polarized component and the blue light BL are emitted toward the afocal device 31B from substantially the entire surface of the polarization conversion element 4 facing the afocal device 31B.

[Configuration of afocal device]
The afocal device 31B has a function of expanding the beam system of the fluorescence YL and the blue light BL incident from the polarization conversion element 4. Specifically, the afocal device 31B is displayed on the second lens 3171 of the second lens array 317 based on the fluorescence YL and the blue light BL that are incident via the light source device 31A and the polarization conversion element 4. Adjust the size of the light source image.
The afocal device 31B includes an afocal lens 315 including a concave lens 3151 and a convex lens 3152. The concave lens 3151 diffuses the fluorescence YL and the blue light BL that have entered, and emits them toward the convex lens 3152. The convex lens 3152 collimates the fluorescent light YL and the blue light BL which are diffused and entered from the concave lens 3151 and emit the parallelized fluorescent light toward the homogenizing device 31C.

[Configuration of homogenizer]
The homogenizer 31C has a function of homogenizing the light incident from the afocal device 31B. The homogenizing device 31C includes a first lens array 316, a second lens array 317, and a superimposing lens 318.
The first lens array 316 has a plurality of first lenses 3161 arranged in an array in a plane orthogonal to the central axis of the light (light flux) emitted from the afocal device 31B (the illumination optical axis Ax). The first lens array 316 divides the light beam incident on the first lens array 316 into a plurality of partial light beams by the plurality of first lenses 3161 of the first lens array 316.
The second lens array 317 has a plurality of second lenses 3171 corresponding to the plurality of first lenses 3161 of the first lens array 316 arranged in an array in a plane orthogonal to the illumination optical axis Ax. The second lens array 317 transmits the partial light flux split by the first lens 3161 by the plurality of second lenses 3171.

The first lens array 316 and the second lens array 317 have the same shape, that is, the same member. The light that has passed through the first lens array 316 and the second lens array 317 as described above is emitted toward the superimposing lens 318.
The superimposing lens 318 superimposes the illumination light WL in the illuminated area to make the illuminance distribution in the illuminated area uniform. In this way, the fluorescence YL and the blue light BL are combined by the superimposing lens 318, and emitted from the lighting device 31 toward the dichroic mirror 321 as the illumination light WL having a uniform illuminance distribution.

[Lens structure and optical path from lighting device to light modulator]
FIG. 3 is a schematic diagram showing a lens configuration and light rays from the illumination device 31 to the light modulation device 34. In addition, in FIG. 3, in order to facilitate the description of the light beam (optical path) incident on the light modulation device 34, the light modulation device 34G is shown, and each component is positioned on a straight line along the illumination optical axis Ax. It is described as a thing.
As described above, the light (blue light BL) emitted from the array light source 311A is condensed by the condenser lens 312 and is incident on the wavelength conversion element 313, as shown in FIG. The light (blue light BL and fluorescence YL) that has entered the wavelength conversion element 313 and has been emitted from the wavelength conversion element 313 is collimated via the collimator optical system 314 and then enters the polarization conversion element 4.

Here, in the projector described in Patent Document 1, even if the polarization conversion element is arranged at the same position as the polarization conversion element 4, since the irradiation area of the light emitted from the collimator optical system 314 is small, the afocal The amount of light incident on the lens 315 decreases.
On the other hand, in the present embodiment, since the polarization conversion element 4 includes the polarization beam splitter 41, the phase difference plate 42, and the reflection member 43, of the light incident on the polarization conversion element 4, the polarization beam splitter 41 The s-polarized light reflected by the polarization separation layer 413 is reflected by the reflection member 43, and the p-polarized light transmitted through the polarization separation layer 413 is also converted into s-polarized light by the retardation plate 42. As a result, the s-polarized light in the irradiation area approximately twice the irradiation area of the light incident on the polarization conversion element 4 can be emitted toward the afocal lens 315.
The aspect ratio of the blue light BL emitted from the wavelength conversion element 313 in the light source device 31A in the wavelength conversion element 313 is such that the polarization separation layer 413 and the reflection member 43 are arranged in each of the second lenses 3171 of the second lens array 317. The aspect ratio of the shape divided into two parts is substantially the same.

  In this way, the light incident on the afocal lens 315 (afocal device 31B) is expanded in the beam system of the incident light, and after the focal length is adjusted, the first light forming the homogenizing device 31C. It is incident on the lens array 316. Then, the light incident on the superimposing lens 318 via the first lens array 316 and the second lens array 317 is reflected by the dichroic mirror 322 via the dichroic mirror 321 as uniformized illumination light WL, and is collimated. The light is incident on the light modulator 34 (34G) via the lens 33 and the incident side polarization plate 341.

[Effects of First Embodiment]
The projector 1 according to the present embodiment described above has the following effects.
Since the pair of polarization conversion elements 4 is arranged between the light source device 31A and the homogenization device 31C, the size can be reduced as compared with the case where the polarization conversion element 4 is arranged in the latter stage of the homogenization device 31C.
Further, since the polarization conversion element 4 has only one set of the polarization separation layer 413, the reflection member 43, and the retardation plate 42, the polarization directions of the incident light can be aligned, so that the plurality of polarization separation layers and the retardation layer are provided. The configuration of the polarization conversion element 4 can be simplified as compared with a configuration in which a plurality of are provided in one direction within a plane orthogonal to the illumination optical axis Ax.

The homogenizing device 31C splits the incident light flux that has been incident through the first lens array 316 through the light source device 31A and the polarization conversion element 4 into a plurality of partial light fluxes, and emits the light through the second lens array 317. Since the partial light fluxes of 1 are superimposed on the illuminated area by the superimposing lens 318, the partial light fluxes can be adjusted so as to illuminate the entire illuminated area. Therefore, the illuminance of the light emitted from the light source device 31A can be made uniform and can be effectively used.
Here, like the illumination device in the projector described in Patent Document 1, after passing through the first lens array and the second lens array, along the polarization separation layer and the reflection layer along one direction in the plane orthogonal to the optical axis. When aligning the polarization directions of light with the plurality of polarization conversion elements arranged alternately, it is necessary to decenter the plurality of first lenses of the first lens array with respect to the second lens array.
On the other hand, according to the present embodiment, since the polarization conversion element 4 is arranged between the light source device 31A and the homogenizing device 31C (afocal device 31B), the plurality of first lens arrays 316 of the first lens array 316 are arranged. Since it is not necessary to decenter the lens 3161 with respect to the second lens array 317, the first lens array 316 and the second lens array 317 can be configured by the same member. Therefore, the number of parts and the manufacturing cost of the lighting device 31 can be reduced.

Here, in this embodiment, a compact condenser lens 312 having a short focal length is adopted as the condenser lens of the light source device 31A in order to achieve miniaturization. Therefore, when the light condensed by the condenser lens 312 directly enters the homogenizing device 31C, the light source image becomes too large, and the light cannot be effectively used.
On the other hand, according to the present embodiment, since the focal length can be lengthened by the afocal lens 315 and the size of the light source image can be adjusted, an image is formed on each of the plurality of second lenses 3171 of the second lens array 317. The light source image can be made smaller. As a result, the utilization efficiency of light in the lighting device 31 can be improved.

  When passing through the polarization conversion element 4, the light flux emitted from the light emitting region of the wavelength conversion element 313 in the light source device 31A is doubled in the direction in which the polarization separation layer 413 and the reflection member 43 are aligned, and doubled. The expanded light flux enters the second lens array 317 via the afocal device 31B and the first lens array 316. Therefore, by passing through the polarization conversion element 4, the light flux from the light source device 31A in the second lens 3171 of the second lens array 317 becomes twice the aspect ratio of the emission region of the wavelength conversion element 313, and The aspect ratio of the shape of the second lens 3171 of the lens array 317 is substantially the same. Therefore, it is possible to further improve the utilization efficiency of the light emitted from the wavelength conversion element 313 in the light source device 31A.

  The light transmitted through the prism 412 arranged on the reflecting member 43 side is totally reflected if it exceeds the critical angle at the interface between the prism 412 and the air layer. The emitted light can be incident on the polarization separation layer 413. Therefore, the utilization efficiency of the light incident on the polarization separation layer 413 can be improved, and the polarization separation function of the polarization conversion element 4 can be improved.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.
The projector according to the present embodiment has the same configuration as the projector 1 described above, but the configuration of the optical unit, specifically, the shape of the lens forming the afocal lens forming the afocal device is different, Different from the projector 1. In the following description, the same or substantially the same parts as those already described are designated by the same reference numerals and the description thereof will be omitted.

FIG. 4 is a schematic diagram showing a lens configuration and light rays between the illumination device and the light modulation device 34 in the projector according to the second embodiment. Note that, in FIG. 4, as in the case of FIG. 3, the light modulation device 34R is shown in addition to the light modulation device 34R so as to facilitate the description of the light beam (optical path) incident on the light modulation device 34, and along the illumination optical axis Ax. It is described that each component is located on a straight line.
An afocal lens 315A forming an afocal device in the optical unit 3A according to the present embodiment includes the concave lens 3151 and the convex lens 5. As shown in FIG. 4, the convex lens 5 has a function of slightly collecting incident light. That is, the afocal lens 315A according to this embodiment has a light condensing property.
As a result, the fluorescence YL and the blue light BL emitted from the polarization conversion element 4 enter the convex lens 5 in a state of being diffused by the concave lens 3151, are condensed by the convex lens 5, and are emitted toward the homogenizing device 31C. To be done.

[Effects of Second Embodiment]
According to the first aspect, since the light incident on the afocal lens 315A can be condensed by the convex lens 5, the spread of the light emitted from the afocal lens 315A can be reduced, so that the first lens array 316 and the first lens array 316 can be formed. The size of the two-lens array 317 can be reduced, and the optical path from the afocal lens 315A to the light modulator 34 can be shortened. Therefore, the arrival efficiency of light to the light modulation device 34 can be improved, and the utilization efficiency of the light emitted from the light source device 31A can be improved.
Therefore, it is possible to reduce the size of the lighting device 31, and thus the projector 1.

[Third Embodiment]
Next, a third embodiment of the present invention will be described.
The projector according to the present embodiment has the same configuration as the projector 1 described above, but the configuration of the optical unit, specifically, the shape of the lens forming the afocal lens forming the afocal device is different, Different from the projector 1. In the following description, the same or substantially the same parts as those already described are designated by the same reference numerals and the description thereof will be omitted.

FIG. 5 is a schematic diagram showing a lens configuration and light rays between the illumination device and the light modulation device in the projector according to the third embodiment. Note that, in FIG. 5, similarly to FIGS. 3 and 4, the light modulation device 34R is shown in addition to the light modulation device 34R so as to facilitate the description of the light beam (optical path) incident on the light modulation device 34. It is described that each component is located on a straight line along Ax.
The afocal device in the optical unit 3B according to this embodiment includes an afocal lens 315B including a concave lens 3151 and a convex lens 6. The concave lens 3151 diffuses the fluorescence YL and the blue light BL that have entered, and emits them toward the convex lens 6. The convex lens 6 has an anamorphic lens surface 61. The anamorphic lens surface 61 has a function of extending the incident light into a light source image in a direction orthogonal to the illumination optical axis Ax. As a result, the fluorescent light YL and the blue light BL diffused and entered from the concave lens 3151 are emitted toward the homogenizing device 31C in a state where the light source image is extended in the above direction by the convex lens 6.
In the present embodiment, the anamorphic lens surface 61 is composed of, for example, a toric lens surface, but it may be a cylindrical lens surface or a prism surface.

[Effects of Third Embodiment]
The projector according to the present embodiment has the following effects in addition to the same effects as the projector 1.
In the present embodiment, since the convex lens 6 has the anamorphic lens surface 61, the spread of the light beam of the light emitted from the afocal lens 315B can be optimized independently in two directions on the plane orthogonal to the illumination optical axis Ax. Therefore, the optical path to the light modulator 34 can be shortened as compared with the first embodiment, and the illumination device 31 can be downsized.
Further, the optical path length of the illuminating device 31 can be shortened as compared with the case where an optical element having an anamorphic lens surface, which will be described later, is arranged. Therefore, the projector can be downsized.

[Modification of Third Embodiment]
In the third embodiment, the convex lens 6 has the anamorphic lens surface 61. However, the present invention is not limited to this, and an optical element having an anamorphic lens surface may be provided on the light incident side of the first lens array 316, that is, between the first lens array 316 and the convex lens 3152. Even in this case, the same effect as that of the third embodiment can be obtained. Further, in this case, since it is not necessary to process the lens surface of the convex lens forming the afocal lens 315B, the normal afocal lens 315 can be adopted.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described.
The projector according to the present embodiment has the same configuration as the projector 1 described above, but the projector has the same configuration as the optical unit, specifically, in that the prism has a prism in addition to the afocal lens constituting the afocal device. Different from 1. In the following description, the same or substantially the same parts as those already described are designated by the same reference numerals and the description thereof will be omitted.

FIG. 6 is a schematic diagram showing a lens configuration and light rays between the illumination device and the light modulation device 34 in the projector according to the fourth embodiment. Note that, in FIG. 6, similarly to FIGS. 3 to 5, the light modulation device 34R is shown in addition to the light modulation device 34R so as to facilitate the description of the light beam (optical path) incident on the light modulation device 34. It is described that each component is located on a straight line along Ax.
The afocal device in the optical unit 3C according to this embodiment includes the afocal lens 315 and the prism 7. The prism 7 is arranged on the light emitting side of the convex lens 3152 that constitutes the afocal lens 315. The prism 7 includes a cylindrical lens surface 71 that optimizes incident light in two directions. As a result, the fluorescence YL and the blue light BL emitted from the polarization conversion element 4 are incident on the prism 7 via the afocal lens 315, optimized by the cylindrical lens surface 71 of the prism 7, and the homogenizing device 31C. It is emitted toward.

[Effects of Fourth Embodiment]
The projector according to the present embodiment described above has the following effects in addition to the same effects as the projector 1.
In the present embodiment, since the prism 7 having the cylindrical lens surface 71 is provided, the spread of the light rays of the light emitted from the afocal lens 315 can be optimized independently in two directions by the prism 7. Thereby, the light reaching efficiency of the light modulator 34 can be improved, and the light emitting efficiency of the light emitted from the light source device 31A can be improved. Therefore, the illumination device 31 can be downsized as compared with the first embodiment, and the projector can be downsized.

[Modification of Fourth Embodiment]
In the fourth embodiment, the prism 7 has the cylindrical lens surface 71. However, the present invention is not limited to this, and a prism having no cylindrical lens surface 71 may be provided. Even in this case, the same effect as that of the projector according to the fourth embodiment can be obtained.

[Modification of Embodiment]
The present invention is not limited to the above-described embodiments, but includes modifications and improvements as long as the object of the present invention can be achieved.
In each of the above-described embodiments, the optical unit 3 includes a plurality of light modulators 34R, 34G, 34B. However, the present invention is not limited to this. For example, one light modulator may be provided. In this case, since the afocal device 31B does not have to be provided, the lighting device 31 can be downsized.

In each of the above-described embodiments, the homogenizing device 31C includes the first lens array 316 and the second lens array 317. However, the present invention is not limited to this. For example, a rod integrator may be adopted instead of the first lens array 316 and the second lens array 317.
In each of the above-described embodiments, the homogenizing device 31C includes the superimposing lens 318. However, the present invention is not limited to this. For example, the superimposing lens 318 may not be provided. In this case, since the superimposing lens 318 is not provided, the homogenizing device 31C and thus the lighting device 31 can be downsized.

  In each of the above embodiments, the aspect ratio of the light emitting region of the wavelength conversion element 313 in the light source device 31A is such that the second lens 3171 of the second lens array 317 is divided into two in the direction in which the polarization separation layer 413 and the reflection member 43 are arranged. It has been decided that the aspect ratio is approximately the same. However, the present invention is not limited to this. For example, the aspect ratio of the light emitted from the light emitting region of the wavelength conversion element 313 in the light source device 31A and the aspect ratio of the shape obtained by dividing the first lens array 316 into two in the above direction may not substantially match.

  In each of the above-described embodiments, the polarization conversion element 4 includes the prism type polarization beam splitter 41. However, the present invention is not limited to this. For example, the polarization conversion element 4 may include a plate-type polarization beam splitter instead of the prism-type polarization beam splitter 41. Even in this case, the same effects as those of the above-described embodiments can be obtained.

  In each of the above-described embodiments, the phase difference plate 42 constituting the polarization conversion element 4 is attached to a position for converting the fluorescence YL of the p polarization component and the polarization component of the blue light BL transmitted through the polarization separation layer 413, that is, the prism 411. It was decided that it was done. However, the present invention is not limited to this. For example, the retardation plate 42 may be attached to a position for converting the fluorescence YL of the s-polarized component reflected by the polarization separation layer 413 and the polarization component of the blue light BL, that is, the prism 412. Even in this case, the same effect as that of each of the above-described embodiments can be obtained.

  In each of the above embodiments, the lighting device 31 includes the array light source 311A as a solid-state light source, and the phosphor layer 3132 includes the YAG phosphor. However, the present invention is not limited to this. For example, the phosphor layer 3132 may include an RG phosphor instead of the YAG phosphor. Further, as the solid-state light source, a UV light source for irradiating UV light may be provided instead of the array light source 311A. In this case, RGB phosphors may be provided as phosphors. Further, for example, an LED (Light Emitting Diode) that emits white light may be provided instead of the array light source 311A. In this case, the wavelength conversion element 313 does not have to be provided, and the second lens 3171 of the second lens array 317 is divided into two in the direction in which the polarization separation layer 413 and the reflection member 43 are arranged, and the aspect ratio of the LED and the light emitting region of the LED. The aspect ratio may be substantially the same.

  In each of the above-described embodiments, the arrangement of each optical component in the optical unit 3 has the configuration shown in FIG. However, the present invention is not limited to this. The arrangement of such an optical unit 3 can be appropriately changed, and for example, a configuration having a substantially L shape in a plan view or a configuration having a substantially U shape in a plan view may be adopted.

In each of the above embodiments, the projector 1 includes the three light modulation devices 34 (34R, 34G, 34B), but the present invention is not limited to this. That is, the present invention can be applied to a projector using two or less or four or more light modulators.
Further, as the light modulator, a light modulator other than liquid crystal such as a digital micromirror device may be used.

  DESCRIPTION OF SYMBOLS 1... Projector, 31... Illumination device, 31A... Light source device, 311... Light source part, 3111... Semiconductor laser, 3112... Collimator lens, 311A... Array light source, 311B... Collimator lens group 312... Condensing lens, 313... Wavelength conversion element 3131... Base material, 3132... Phosphor layer, 3133... Motor, 314... Collimator optical system, 3142... Collimator lens, 315... Afocal lens, 3151... Concave lens, 3152... Convex lens, 315A... Afocal Lens 315B... Afocal lens, 316... First lens array, 3161... First lens, 317... Second lens array, 3171... Second lens, 318... Superimposing lens, 31A... Light source device, 31B... Afocal device, 31C... Homogenizing device, 4... Polarization conversion element, 41... Polarization beam splitter, 411... Prism, 412... Prism, 413... Polarization separation layer, 42... Retardation plate (retardation layer), 43... Reflection member (reflection layer) ), 61... Anamorphic lens surface, 7... Prism, 71... Cylindrical lens surface, Ax... Illumination optical axis, BL... Blue light, WL... Illumination light, YL... Fluorescence.

Claims (4)

A light source device for emitting light,
A polarization conversion element that aligns the polarization directions of the light emitted from the light source device,
A homogenizing device for homogenizing the illuminance in the plane orthogonal to the central axis of the light incident from the polarization conversion element,
A prism having a cylindrical lens surface, which is provided between the polarization conversion element and the homogenizing device,
The polarization conversion element,
Of the light emitted from the light source device, a polarization separation layer that transmits one polarized light and reflects the other polarized light,
The other polarized light reflected by the polarization separation layer, a reflection layer that reflects in the same direction as the traveling direction of the one polarized light transmitted through the polarization separation layer,
It is arranged on the optical path of one of the one polarized light transmitted through the polarization separation layer and the other polarized light reflected by the reflection layer, and converts the polarization direction of the polarized light. And a retardation layer,
The polarization conversion element has one set of the polarization separation layer, the reflection layer and the retardation layer,
The homogenizing device,
A first lens array in which a plurality of first lenses are arranged in a plane orthogonal to a central axis of an incident light flux, and the light flux incident by the plurality of first lenses is divided into a plurality of partial light fluxes;
A second lens array in which a plurality of second lenses corresponding to the plurality of first lenses are arranged in the orthogonal plane;
A superimposing lens that is disposed on the light emission side of the second lens array, and that superimposes the plurality of partial light beams that are divided by the first lens array and are incident through the plurality of second lenses on an illuminated region; An illuminating device comprising: A light source device for emitting light,
A polarization conversion element that aligns the polarization directions of the light emitted from the light source device,
A homogenizing device for homogenizing the illuminance in the plane orthogonal to the central axis of the light incident from the polarization conversion element,
The polarization conversion element,
Of the light emitted from the light source device, a polarization separation layer that transmits one polarized light and reflects the other polarized light,
The other polarized light reflected by the polarization separation layer, a reflection layer that reflects in the same direction as the traveling direction of the one polarized light transmitted through the polarization separation layer,
It is arranged on the optical path of one of the one polarized light transmitted through the polarization separation layer and the other polarized light reflected by the reflection layer, and converts the polarization direction of the polarized light. A retardation layer,
A prism for fixing the polarization separation layer from both sides,
The polarization conversion element has one set of the polarization separation layer, the reflection layer and the retardation layer,
An illumination device, wherein an air layer is provided between the prism arranged on the reflection layer side and the reflection layer. The illumination device according to claim 1 ,
The light source device,
A light source section,
A condenser lens for condensing light incident from the light source unit,
A wavelength conversion element for converting a part of the light from the condenser lens into a wavelength,
A collimator lens for collimating light from the light emitting region of the wavelength conversion element,
The aspect ratio of the light emitting region of the wavelength conversion element is substantially equal to the aspect ratio of a shape obtained by dividing each of the plurality of second lenses of the second lens array in the direction in which the polarization separation layer and the reflection layer are arranged. A lighting device characterized by the above. A lighting device according to any one of claims 1 to 3 ,
A light modulator for modulating the light emitted from the lighting device;
A projection optical device that projects the light modulated by the light modulation device.

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