JP6369037B2 - Light source device, projector - Google Patents

Description

  The present invention relates to a light source device and a projector.

  2. Description of the Related Art Conventionally, a projector that illuminates a light modulation device with light emitted from a light source device and enlarges and projects the image light modulated and emitted by the light modulation device onto a screen using a projection optical system is widely known.

  As a light source for a projector, a laser light source such as a semiconductor laser (LD) capable of obtaining light with high luminance and high output has attracted attention. In a projector using a laser light source, excitation light (blue light) emitted from a semiconductor laser and fluorescent light (yellow light) generated by exciting a phosphor with this excitation light are used as illumination light. It has been known.

  Patent Document 1 discloses a projector including a light source device including a phosphor layer and a convex meniscus lens that suppresses the spread of light emitted from the light source device.

JP 2011-128482 A

  In the projector shown in Patent Document 1, a phosphor layer is disposed on a plurality of bases having a rectangular shape in cross section. Although the phosphor layer excited by the semiconductor laser that can obtain light with high luminance and high output becomes very high temperature, the structure of the conventional literature is insufficiently cooled. This may lead to deterioration of the phosphor layer and a decrease in luminous efficiency of the phosphor layer.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a light source device and a projector that can improve the cooling efficiency of the phosphor layer.

A light source device according to one aspect of the present invention includes a light source, a substrate having a first surface, a convex portion provided on the first surface and having an inclined surface inclined with respect to the first surface, and the convex A phosphor layer that is provided on the part and generates light of a second wavelength band different from the light of the first wavelength band by being excited by light of the first wavelength band emitted from the light source; A meniscus lens disposed on the opposite side of the phosphor layer from the convex portion and having a light incident surface facing the light exit surface of the phosphor layer as a concave surface, and the inclined surface includes the meniscus curved so as to follow the curvature of the light incident surface of the lens, characterized in Rukoto.

  According to the light source device which is an embodiment of the present invention, the convex portion including the phosphor layer is configured to include the inclined surface, and thus air smoothly flows between the convex portion and the meniscus lens, The body layer can be efficiently cooled. Moreover, since the surface area of the convex portion is increased by providing the inclined surface, it is possible to enhance the heat dissipation effect on the phosphor layer.

In the light source device according to one aspect of the present invention, the meniscus lens may be configured such that a maximum incident angle of light rays from the center of the phosphor layer to the light incident surface is less than 60 °. .
According to the light source device which is an embodiment of the present invention, Fresnel loss of light incident on the concave surface of the meniscus lens can be reduced, and the incident efficiency of light emitted from the phosphor layer can be increased.

In the light source device according to one aspect of the present invention, the convex portion may have a flat surface, and the phosphor layer may be provided on the flat surface.
According to the light source device which is one form of this invention, a fluorescent substance layer is easy to provide on a convex part, and manufacture becomes easy.

In the light source device according to one embodiment of the present invention, the phosphor layer may be provided on the inclined surface.
According to the light source device according to one aspect of the present invention, the phosphor layer is formed so as to follow the inclined surface of the convex portion, so that air flows more smoothly on the surface of the phosphor layer. . Thereby, the cooling efficiency of the phosphor layer is improved.

In the light source device according to one aspect of the present invention, the meniscus lens has an end surface that intersects an optical axis of the meniscus lens outside the light incident surface, and the end surface is located on the substrate rather than the phosphor layer. It is good also as a structure located in the side.
According to the light source device which is an embodiment of the present invention, the light incident surface of the meniscus lens and the phosphor layer can be arranged close to each other, so that most of the light emitted from the phosphor layer is incident on the meniscus lens. It becomes possible.

The light source device which is one form of this invention WHEREIN: It is good also as a structure by which the reflection preventing structure is given to the said light-incidence surface of the said meniscus lens.
According to the light source device which is an embodiment of the present invention, Fresnel loss of light incident on the concave surface of the meniscus lens can be reduced, and the incident efficiency of light emitted from the phosphor layer can be increased.

The light source device which is one form of this invention WHEREIN: It is good also as a structure by which the said convex part and the said meniscus lens which make a planar view circular shape are arrange | positioned coaxially.
According to the light source device according to one aspect of the present invention, since the convex portion having the inclined surface and the meniscus lens are arranged coaxially, a space between the convex portion and the meniscus lens is uniformly formed around the axis. Is done. Thereby, air smoothly flows through the space between the convex portion (phosphor layer) and the meniscus lens.

The light source device which is one form of this invention WHEREIN: It is good also as a structure by which the said convex part and the said board | substrate are integrally formed.
According to the light source device which is one form of this invention, the adhesive agent which adhere | attaches a convex part and a board | substrate becomes unnecessary. Thereby, since it becomes possible to form a convex part and a board | substrate using a material with high heat conductivity, the heat dissipation of a fluorescent substance layer improves. Therefore, it is possible to prevent the phosphor layer from being deteriorated and the luminous efficiency from being lowered.

The light source device which is one form of this invention WHEREIN: It is good also as a structure by which the said convex part is comprised from copper.
According to the light source device which is one form of this invention, the heat dissipation with respect to a fluorescent substance layer can be improved by forming a convex part using copper with high heat conductivity.

In the light source device according to one aspect of the present invention, the phosphor layer may have a rectangular planar shape.
According to the light source device which is one form of this invention, it is easy to manufacture a fluorescent substance layer. In addition, for example, when irradiating the irradiated region via an optical system such as a multi-lens array having a rectangular lens in plan view, the light emitted from the rectangular phosphor layer has the shape of the multi-lens array. In general, they match and the loss of irradiation light is reduced.

A projector according to an aspect of the present invention includes an illumination device that illuminates illumination light, a light modulation device that modulates the illumination light according to image information to form image light, and a projection optical system that projects the image light And the light source device is used as the illumination device.
According to the light source device which is an embodiment of the present invention, a projector with high reliability can be obtained by including the light source device with high cooling efficiency for the phosphor layer.

1 is a diagram illustrating a schematic configuration of a projector according to a first embodiment. The figure which shows schematic structure of the light source device in 1st Embodiment. The figure which shows each structural example of the fluorescent substance layer with which a fluorescence light emitting element is provided. The figure which shows a fluorescence light emitting element and the periphery structure. The perspective view which shows schematic structure of a fluorescence light emitting element. The figure which shows the Lambert divergence angle (theta) in a fluorescent substance layer. (A) is a figure which shows the flow of the air around the fluorescent substance layer in 1st Embodiment, (B) is a figure which shows the flow of the air around the fluorescent substance layer in the conventional structure. The figure which shows the comparison with the effective diameter of the 1st pick-up lens in 1st Embodiment, and the effective diameter of the conventional 1st pick-up lens. (A) is a figure which shows the maximum incident angle of the light ray which injects into a meniscus lens from a fluorescent substance layer, (B) is a figure which shows the maximum incident angle with respect to the conventional plano-convex lens. The figure which shows the structure of the 1st pick-up lens provided with the antireflection film in 2nd Embodiment. The figure which shows the reflection characteristic at the time of forming the conventional anti-reflective film on a glass substrate (nd = 1.7723). The figure which shows the structure at the time of providing a moth-eye sheet | seat as another antireflection structure. The figure which shows the example of a shape of the convex part in the fluorescence light emitting element in 3rd Embodiment. The figure which shows the example of a shape of the convex part in the fluorescence light emitting element in 4th Embodiment. The figure which shows the example of a shape of the convex part in the fluorescence light emitting element in 5th Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

[projector]
First, an example of the projector according to the first embodiment of the invention will be described.
FIG. 1 is a diagram illustrating a schematic configuration of a projector according to the first embodiment.

  As shown in FIG. 1, the projector 1 is a projection-type image display device that displays a color image (image) on a screen (projected surface) SCR, and includes an illumination device 20A, a color separation optical system 3, and a light modulation device. 4R, a light modulation device 4G, a light modulation device 4B, a synthesis optical system 5, and a projection optical system 6 are roughly provided.

  The light modulation device 4R, the light modulation device 4G, and the light modulation device 4B are three light modulation devices corresponding to each color light of the red light LR, the green light LG, and the blue light LB. The illumination device 20A uses, as a light source, a semiconductor laser (laser light source) 21a (FIG. 2) that can obtain light with high luminance and high output.

  The illuminating device 20A mixes excitation light (blue light) emitted from the semiconductor laser 21a with fluorescent light (yellow light) generated by exciting the phosphor with this excitation light, thereby illuminating light (white light). ) WL is obtained. The illuminating device 20A irradiates the color separation optical system 3 with the illumination light WL adjusted to have a uniform illuminance distribution.

  The color separation optical system 3 includes a first dichroic mirror 7a and a second dichroic mirror 7b, a first reflection mirror 8a, a second reflection mirror 8b and a third reflection mirror 8c, a first relay lens 9a and a second relay lens 9b. And roughly.

  Among these, the first dichroic mirror 7a has a function of separating the illumination light WL from the illumination device 20A into the red light LR and other color lights (green light LG, blue light LB), and the separated red light LR. , And other color light (green light LG, blue light LB) is reflected.

  On the other hand, the second dichroic mirror 7b has a function of separating the other color light (green light LG, blue light LB) into green light LG and blue light LB, reflects the separated green light LG, and is blue. Transmits light LB.

  The first reflection mirror 8a is disposed in the optical path of the red light LR, and reflects the red light LR transmitted through the first dichroic mirror 7a toward the light modulation device 4R.

  On the other hand, the second reflection mirror 8b and the third reflection mirror 8c are arranged in the optical path of the blue light LB, and reflect the blue light LB transmitted through the second dichroic mirror 7b toward the light modulation device 4B. Note that it is not necessary to dispose a reflection mirror in the optical path of the green light LG, and the green light LG is reflected from the second dichroic mirror 7b toward the light modulation device 4G.

  The first relay lens 9a and the second relay lens 9b are disposed downstream of the second reflection mirror 8b in the optical path of the blue light LB. The first relay lens 9a and the second relay lens 9b have a function of compensating for the optical loss of the blue light LB due to the optical path length of the blue light LB being longer than the optical path lengths of the red light LR and the green light LG. Yes.

  Each of the light modulation devices 4R, 4G, and 4B includes a liquid crystal panel, and forms image light obtained by modulating the color lights LR, LG, and LB according to image information while passing the color lights LR, LG, and LB. . In addition, a pair of polarizing plates (not shown) are arranged on the incident side and the emission side of each of the light modulation devices 4R, 4G, 4B, and a mechanism that allows only linearly polarized light in a specific direction to pass therethrough. It has become.

  Further, on the light incident surface side of each of the light modulation devices 4R, 4G, and 4B, a field lens 10R, a field lens 10G, and a parallel lens that collimates the color lights LR, LG, and LB incident on the light modulation devices 4R, 4G, and 4B. A field lens 10B is disposed.

  The combining optical system 5 is composed of a cross dichroic prism. When the image light from each of the light modulation devices 4R, 4G, and 4B is incident, the combining optical system 5 combines the image light corresponding to each color light LR, LG, and LB and combines them. The emitted image light is emitted toward the projection optical system 6.

  The projection optical system 6 includes a projection lens group, and enlarges and projects the image light combined by the combining optical system 5 toward the screen SCR. Thereby, an enlarged color video (image) is displayed on the screen SCR.

[Light source device]
FIG. 2 is a diagram illustrating a schematic configuration of the light source device according to the first embodiment.
As illustrated in FIG. 2, the illumination device 20 </ b> A of the present embodiment schematically includes a light source device 2, an integrator optical system 29, a polarization conversion element 30, and a superimposing optical system 31.
The light source device 2 includes an array light source (light source) 21, a collimator optical system 22, an afocal optical system 23, a homogenizer optical system 24, a first reflecting unit 60, an optical element 25A including a polarization separation element 50A, A first retardation plate 26, a pickup optical system 27, a fluorescent light emitting element 28, and a heat sink 34 are provided.

  The array light source 21 has an optical axis ax1. Assuming that the optical axis of the fluorescent light YL emitted from the fluorescent light emitting element 28 is ax2, the optical axis ax1 and the optical axis ax2 are in the same plane and are orthogonal to each other.

  The array light source 21 is composed of a plurality of semiconductor lasers 21a arranged. Specifically, the array light source 21 is configured by arranging a plurality of semiconductor lasers 21a in an array in a plane orthogonal to the optical axis ax1.

  On the optical axis ax1, the array light source 21, the collimator optical system 22, the afocal optical system 23, the homogenizer optical system 24, and the optical element 25A are arranged in this order. On the other hand, on the optical axis ax2, the fluorescent light reflecting portion 32b, the phosphor layer 32, the excitation light transmitting / reflecting portion 32a, the pickup optical system 27, the first phase difference plate 26, the optical element 25A, the integrator, and the like. The optical system 29, the polarization conversion element 30, and the superimposing optical system 31 are arranged in this order.

  The semiconductor laser 21a emits excitation light (blue light) BL having a peak wavelength in a wavelength region of 440 to 480 nm, for example, as a first light flux in the first wavelength band. The excitation light BL emitted from each semiconductor laser 21a is coherent linearly polarized light, and is emitted in parallel with the optical axis ax1 toward the polarization separation element 50A.

  In the array light source 21, the polarization direction of the excitation light BL emitted from each semiconductor laser 21a is matched with the polarization direction of the polarization component (eg, S polarization component) reflected by the polarization separation element 50A. The excitation light BL emitted from the array light source 21 enters the collimator optical system 22.

  The collimator optical system 22 converts the excitation light BL emitted from the array light source 21 into parallel light. For example, it comprises a plurality of collimator lenses 22a arranged in an array corresponding to each semiconductor laser 21a. The excitation light BL converted into parallel light by passing through the collimator optical system 22 enters the afocal optical system 23.

  The afocal optical system 23 adjusts the size (spot diameter) of the excitation light BL, and is composed of, for example, two afocal lenses 23a and afocal lenses 23b. The excitation light BL whose size is adjusted by passing through the afocal optical system 23 is incident on the homogenizer optical system 24.

  The homogenizer optical system 24 converts the light intensity distribution of the excitation light BL into a uniform state (so-called top hat distribution). For example, it consists of a pair of multi-lens array 24a and multi-lens array 24b. The excitation light BL that has been converted to a uniform light intensity distribution by the homogenizer optical system 24 is incident on the fluorescent light-emitting element 28 via the polarization separation element 50A.

  The optical element 25A is composed of, for example, a dichroic prism having wavelength selectivity, and the dichroic prism has an inclined surface K that forms an angle of 45 ° with respect to the optical axis ax1. Further, the inclined surface K forms an angle of 45 ° with respect to the optical axis ax2. Furthermore, the optical element 25A is arranged so that the intersection of the optical axes ax1 and ax2 orthogonal to each other and the optical center of the inclined surface K coincide. On the inclined surface K, a polarization separation element 50A having wavelength selectivity is provided.

The polarization separation element 50A converts the excitation light BL of the first wavelength band incident on the polarization separation element 50A into an S polarization component (one polarization component) and a P polarization component (the other polarization component) for the polarization separation element 50A. It has a polarization separation function to separate. The polarization separation element 50A reflects the S-polarized component of the excitation light BL and transmits the P-polarized component of the excitation light BL. In addition, the polarization separation element 50A has a color separation function of transmitting light having a second wavelength band different from the first wavelength band from light incident on the polarization separation element 50A regardless of the polarization state. ing.
The optical element 25A is not limited to a prism shape such as a dichroic prism, and a parallel plate dichroic mirror may be used.

  The excitation light BL incident on the polarization separation element 50A is reflected toward the fluorescent light-emitting element 28 as S-polarized excitation light BLs because the polarization direction thereof coincides with the S-polarization component.

  The first retardation plate 26 is disposed in the optical path between the polarization separation element 50A and the excitation light transmitting / reflecting portion 32a. As the first retardation plate 26, for example, a ¼ wavelength plate (λ / 4 plate) can be used. S-polarized (linearly polarized) excitation light BLs incident on the first retardation plate 26 is converted into circularly-polarized excitation light BLc and then incident on the pickup optical system 27.

  The pickup optical system 27 collects the excitation light BLc toward the phosphor layer 32, and includes, for example, a first pickup lens 27a, a second pickup lens 27b, and a third pickup lens 27c.

The fluorescent light emitting element 28 includes a phosphor layer 32 and a support portion 33 that supports the phosphor layer 32. The support portion 33 includes a holding substrate 35 and a convex portion 36 provided on the first surface 35 a of the holding substrate 35. The phosphor layer 32 is fixed to the convex portion 36 with an adhesive (not shown) in a state where the surface opposite to the surface on which the excitation light BLc is incident is in contact with the convex portion 36. As the phosphor layer 32, it is preferable to use a layer excellent in heat resistance and surface processability.
The configuration of the fluorescent light emitting element 28 will be described in detail later.

  The heat sink 34 is fixed to the holding substrate 35 of the fluorescent light emitting element 28, and has a heat radiating plate 34A and a plurality of heat radiating fins 34B. The heat sink 34 prevents heat deterioration of the phosphor layer 32 by radiating heat of the phosphor layer 32.

FIG. 3A, FIG. 3B, and FIG. 3C are diagrams illustrating examples of the configuration of the phosphor layer included in the fluorescent light-emitting element. Hereinafter, a description will be given with reference to FIGS.
As shown in FIG. 3A, FIG. 3B, and FIG. 3C, an excitation light transmitting / reflecting portion 32a is provided on the light emission surface 32A side of the phosphor layer 32. The excitation light transmitting / reflecting unit 32a makes a part of the excitation light BLc incident from the pickup optical system 27 shown in FIG. 2 incident on the polarization separation element 50A via the first phase plate 26. The other part of light (first wavelength band light) BLc2 of the excitation light BLc incident from the pickup optical system 27 is diffusely reflected and transmitted toward the phosphor layer 32. The excitation light transmitting / reflecting part 32a transmits light (second wavelength band light) BLc2 from the phosphor layer 32.

  Further, a fluorescent light reflecting portion 32b is provided on the opposite side of the phosphor layer 32 from the excitation light transmitting / reflecting portion 32a. The fluorescent light reflecting portion 32b is made of a specular reflection surface. The specular reflection surface can be formed by providing the reflection film 32c. In addition, when the convex portion 36 that supports the phosphor layer 32 has light reflection characteristics, the specular reflection surface can be formed by mirroring the surface of the convex portion 36 that faces the phosphor layer 32.

  The phosphor layer 32 in the present embodiment includes a phosphor that is excited by absorbing light BLc2 that is light in the first wavelength band, and fluorescence that is excited by this light (light in the first wavelength band) BLc2. The body generates fluorescent light (yellow light YL) having a peak wavelength in a wavelength range of 500 to 700 nm, for example, as light of a second wavelength band different from the first wavelength band.

  The fluorescent light reflecting section 32b reflects a part of the fluorescent light YL1 generated in the fluorescent material layer 32 and emits the fluorescent light YL1 to the outside of the fluorescent material layer 32, to the polarization separation element 50A (FIG. 2). Make it incident. Further, the fluorescent light reflecting section 32b reflects the component of the light BLc2 that has not been absorbed by the phosphor layer 32 so as to enter the polarization separation element 50A via the first retardation plate 26 (FIG. 2). . Of the fluorescent light generated in the fluorescent layer 32, another part of the fluorescent light YL2 is emitted outside the fluorescent layer 32 without passing through the fluorescent light reflecting portion 32b.

  As described above, the fluorescent light (yellow light) YL (YL1, YL2) generated in the phosphor layer 32 and the components of the light BLc2 that are not absorbed by the phosphor layer 32 cause the excitation light transmitting / reflecting part 32a. The light passes through and enters the pickup optical system 27 together with the light BLc1.

  As shown in FIG. 2, the fluorescent light (yellow light) YL incident on the pickup optical system 27 further passes through the first retardation plate 26. At this time, since the fluorescent light YL is non-polarized light whose polarization direction is not uniform, after passing through the first phase difference plate 26, the fluorescent light YL is incident on the polarization separation element 50A without being polarized. Then, the fluorescent light YL passes through the polarization separation element 50A.

  Since the light BLc1 is light diffusely reflected by the excitation light transmitting / reflecting unit 32a, the polarization state of the light BLc1 is disturbed by diffuse reflection. Further, the polarization state of the component of the light BLc 2 that has not been absorbed by the phosphor layer 32 is disturbed by the phosphor layer 32. Therefore, the component of the excitation light that has not been absorbed by the phosphor layer 32 and the light BLc 1 behave the same after entering the pickup optical system 27. Therefore, the behavior of the light BLc1 will be described below.

  The light (blue light) BLc1 reflected by the excitation light transmitting / reflecting portion 32a passes through the pickup optical system 27 and the first retardation plate 26 again. The first retardation plate 26 has a function of converting circularly polarized light into linearly polarized light. However, since the polarization state of the light BLc1 is disturbed, the light BLc1 includes light that is converted into P-polarized blue light BLp and light that is converted into S-polarized blue light BLs'.

  The P-polarized blue light BLp that has passed through the first phase plate 26 passes through the polarization separation element 50A and is used as illumination light WL. On the other hand, the S-polarized blue light BLs ′ that has passed through the first retardation plate 26 is reflected by the polarization separation element 50 </ b> A and is incident on the first reflector 60. The first reflecting unit 60 reflects the incident light so as to enter the polarization separation element 50A. Thus, the first reflection unit 60 reflects at least a part of the light traveling from the excitation light reflection unit via the polarization separation element 50A toward the array light source 21 so as to enter the polarization separation element 50A. To do.

  The first reflecting unit 60 includes a plurality of mirrors 61. The plurality of mirrors 61 are provided at positions different from the positions through which the excitation light BL traveling from the array light source 21 to the polarization separation element 50A passes. Accordingly, the first reflecting unit 60 efficiently reflects the blue light BLs ′ reflected by the polarization separation element 50A toward the polarization separation element 50A without blocking the excitation light BL emitted from the array light source 21. be able to. Accordingly, it is possible to obtain the blue light BLs ′ having a uniform illuminance distribution while reflecting the blue light BLs ′.

  The blue light BLs ′ is used as the illumination light WL together with the fluorescent light YL transmitted through the polarization separation element 50A. That is, the blue light BLs' and the fluorescent light YL are emitted from the polarization separation element 50A in the same direction. Thereby, white illumination light WL obtained by combining the blue light BLs ′ and the fluorescent light (yellow light) YL is obtained.

The illumination light WL emitted from the polarization separation element 50A enters the integrator optical system 29. The integrator optical system 29 makes the illuminance distribution of the illumination light WL uniform. The integrator optical system 29 includes, for example, a lens array 29a and a lens array 29b.
The lens arrays 29a and 29b are made up of a plurality of microlenses arranged in an array.

  The illumination light WL that has passed through the integrator optical system 29 enters the polarization conversion element 30. The polarization conversion element 30 aligns the polarization direction of the illumination light WL. The polarization conversion element 30 includes, for example, a polarization separation film, a phase difference plate, and a mirror. The polarization conversion element 30 aligns the polarization direction of the fluorescent light YL whose polarization direction is not aligned with the polarization direction of the S-polarized blue light BLs ′, so that the other polarization component is changed to one polarization component, for example, a P polarization component. Is converted to an S-polarized component.

  The illumination light WL whose polarization direction is aligned by passing through the polarization conversion element 30 enters the superimposing optical system 31. The superimposing optical system 31 superimposes the illumination light WL emitted from the polarization conversion element 30. The superposition optical system 31 is composed of, for example, a superposition lens. The illumination light WL superimposed by passing through the superimposing optical system 31 is emitted from the light source device 2 with its luminance distribution made uniform.

Next, the configuration of the fluorescent light emitting element 28 and its periphery will be described in detail.
FIG. 4 is a diagram showing a configuration of the fluorescent light emitting element and its periphery. FIG. 5 is a perspective view showing a schematic configuration of the fluorescent light emitting device.
As shown in FIGS. 4 and 5, the fluorescent light emitting element 28 includes a fluorescent layer 32 that is rectangular in a plan view and a support portion 33 that supports the fluorescent layer 32.

  The support portion 33 includes a holding substrate (substrate) 35 having a first surface 35a, and a convex portion 36 provided substantially at the center on the first surface 35a. In the present embodiment, the holding substrate 35 and the convex portion 36 are integrally formed and are made of pure copper having high thermal conductivity.

  The convex portion 36 has a bottom surface 36b in contact with the first surface 35a, an inclined surface 36c inclined with respect to the first surface 35a, and a flat surface (end surface) 36a parallel to the first surface 35a. The planar shapes of the bottom surface 36b and the flat surface 36a of the convex portion 36 are circular, and the area of the flat surface 36a is smaller than the area of the bottom surface 36b. Further, the inclined surface 36c that connects the flat surface 36a and the bottom surface 36b is a curved surface that is curved outward in a sectional view.

The phosphor layer 32 is held on the flat surface 36 a of the convex portion 36. The phosphor layer 32 is fixed to the approximate center of the flat surface 36a with an adhesive (not shown). The material of the adhesive is not particularly limited, but it is preferable to use an adhesive having excellent thermal conductivity. Thereby, the heat generated in the phosphor layer 32 is easily dissipated through the convex portion 36, the holding substrate 35, and the adhesive.
In addition, by providing the flat surface 36 a on the convex portion 36, the phosphor layer 32 can be easily aligned with the convex portion 36.

  The phosphor layer 32 converts the wavelength of the excitation light from the semiconductor laser 21a (FIG. 2), a phosphor (not shown) that is excited by absorbing the excitation light having a wavelength of 446 nm, and a binder containing the phosphor. (Not shown). As such a phosphor layer 32, for example, a phosphor layer in which a phosphor is dispersed in an inorganic binder such as alumina is preferably used. Alternatively, a phosphor layer obtained by sintering a phosphor without using a binder can be used.

When viewed from the normal direction of the holding substrate 35, the planar shapes of the holding substrate 35 and the phosphor layer 32 are both rectangular. The planar dimension of the phosphor layer 32 is smaller than the planar dimension of the holding substrate 35. The planar shape of the phosphor layer 32 is preferably rectangular, but more preferably square. Thereby, manufacture of the fluorescent substance layer 32 becomes easy.
Note that the planar shape of the phosphor layer 32 is not limited to the above, and may be a circle.

The light emitted from the phosphor layer 32 is a diverging light having an angular distribution close to Lambert radiation.
FIG. 6 is a diagram showing a divergence angle θ of light emitted from the phosphor layer. About 98% of the light emitted from the phosphor layer is emitted at a divergence angle θ within 160 °. Therefore, in the present embodiment, light having a divergence angle θ of 160 ° or less among the light from the phosphor layer 32 is efficiently incident on the first pickup lens 27a.

Returning to FIG. 4, the first pickup lens 27 a in the present embodiment faces the phosphor layer 32 and the support portion 33 and is concentrically (coaxially) with the convex portion 36 of the support portion 33 in plan view. Has been placed. The first pickup lens 27a is a meniscus lens in which a light incident surface 27A (a lens surface on which light from the phosphor layer 32 is incident) facing the light emission surface 32A of the phosphor layer 32 is a concave surface, and is made of glass or Made of quartz, plastic, etc. The convex part 36 mentioned above is comprised so that the inclined surface 36c may follow the inclination of 27 A of light-incidence surfaces which comprise the concave surface of the 1st pick-up lens 27a. That is, when viewed from these cross-sectional directions, the inclined surface 36c of the convex portion 36 and the light incident surface 27A of the first pickup lens 27a are inclined in the same direction.
Here, it is more preferable that the curvature of the inclined surface 36c and the curvature of the light incident surface 27A substantially coincide.

  The first pickup lens 27a is disposed at a predetermined distance from the phosphor layer 32 and the support portion 33, and a space for allowing air to flow between the phosphor layer 32 and the first pickup lens 27a. 38 is formed. When the phosphor layer 32 is fixed as in the present embodiment, air tends to stay around the phosphor layer 32. Therefore, in the present embodiment, the structure is such that air smoothly flows between the fluorescent light emitting element 28 and the first pickup lens 27a disposed opposite to the fluorescent light emitting element 28.

  As described above, the inclined surface 36c of the convex portion 36 holding the phosphor layer 32 is curved so as to follow the curvature of the light incident surface 27A of the first pickup lens 27a made of a meniscus lens. Furthermore, since the arrangement of the convex portion 36 and the first pickup lens 27a is a substantially concentric relationship, there is an effect that the air resistance is small in the space 38 formed between them and the air easily flows. That is, the structure is such that air does not easily stay around the phosphor layer 32. Thereby, since air flows smoothly in the space 38, the light emission surface 32A of the phosphor layer 32 is always exposed to new cooling air, and the cooling effect of the phosphor layer 32 is improved.

FIG. 7A is a diagram showing air flow paths around the phosphor layer in the present embodiment, and FIG. 7B is a diagram showing air flow paths around the phosphor layer in the conventional configuration.
In the case of the conventional configuration in which the phosphor layer 32 is provided on the convex portion 51 having a rectangular cross section as shown in FIG. 7B, the vicinity of the boundary between the convex portion 51 and the holding substrate 35 and the flat end surface 51 a of the convex portion 51. A turbulent air flow occurs in the vicinity of the corner formed by the side 51c. Then, air does not flow smoothly in the space 48, and air stays around the phosphor layer 32.

  On the other hand, in the configuration of the present embodiment shown in FIG. 7A, the convex portion 36 that holds the phosphor layer 32 has an inclined surface 36c that is substantially equal to the curvature of the light incident surface 27A of the first pickup lens 27a. doing. Therefore, air smoothly flows in the space 38 formed between the convex portion 36 (phosphor layer 32) and the first pickup lens 27a. As a result, air does not stay around the phosphor layer 32.

  Further, the first pickup lens 27a in the present embodiment has an edge portion 27B. Furthermore, the end surface 11 that intersects the optical axis of the first pickup lens 27a that is a meniscus lens is provided outside the light incident surface 27A. The first pickup lens 27 a is disposed so that the end surface 11 is positioned closer to the holding substrate 35 than the light emission surface 32 </ b> A of the phosphor layer 32.

  With the first pickup lens 27 a having the edge portion 27 </ b> B, the light incident surface 27 </ b> A can be disposed close to the light emitting surface 32 </ b> A of the phosphor layer 32. Further, by providing the edge portion 27B on the outer periphery of the lens, the handling of the first pickup lens 27a is improved.

FIG. 8 is a diagram showing a comparison between the effective diameter D1 of the first pickup lens 27a in the first embodiment and the effective diameter D of the first pickup lens 54 of the comparative example.
In the drawing, the first pickup lens 27a in the present embodiment is indicated by a solid line, and the first pickup lens 54 of the comparative example is indicated by a two-dot chain line or a broken line. Here, a lens having no edge portion is shown as the first pickup lens 54 of the comparative example. Further, light emitted from the center of the phosphor layer 32 at a divergence angle of 160 ° is indicated by a dashed arrow.

  When trying to receive most of the light emitted from the phosphor layer 32, the effective diameter D of the lens increases as in the first pickup lens 54 of the comparative example shown in FIG. 8, which increases the size of the light source device. Connected. Further, the conventional first pickup lens 54 is difficult to handle because it has no edge portion.

  In the present embodiment, the first pickup lens 27a is disposed closer to the phosphor layer 32 than the first pickup lens 54 of the comparative example. As indicated by a broken line in the figure, when the first pickup lens 54 is arranged so that the phosphor layer 32 enters the space in the concave portion of the light incident surface 54A, an unnecessary portion 54b where light from the phosphor layer 32 does not enter. (The portion indicated by hatching in the figure) becomes unnecessary. By removing the unnecessary portion 54b, the edge portion 27B can be formed. Accordingly, the effective diameter D1 of the first pickup lens 27a is reduced, and the entire lens can be reduced in size. In addition, since the lens occupying area can be made smaller than in the prior art, the distance between the light emitting surface 32A of the phosphor layer 32 and the light incident surface 27A of the first pickup lens 27a in the optical axis direction becomes shorter, and as a result, the light source This leads to downsizing of the entire device 2. Furthermore, in the present embodiment, the first pickup lens 27a is arranged so that the end surface 11 of the edge portion 27B is positioned closer to the holding substrate 35 than the light emission surface 32A of the phosphor layer 32. Thereby, the size of the first pickup lens 27a can be made compact without significantly reducing the incident efficiency of light from the phosphor layer 32.

  Depending on the shape and the like of the first pickup lens 27a, the end surface 11 of the light incident surface 27A and the light exit surface 32A of the phosphor layer 32 may be arranged to coincide with each other in the optical axis direction.

  FIG. 9A is a diagram showing the maximum incident angle of light rays that enter the meniscus lens from the phosphor layer, and FIG. 9B is a diagram showing the maximum incident angle with respect to a conventional plano-convex lens. Here, the maximum incident angle refers to the normal of the light incident surface at the position where the light emitted from the center of the phosphor layer 32 with the maximum divergence angle is incident on the light incident surface of the lens and the traveling direction of the incident light. It is an angle to make.

  As shown in FIG. 9A, the first pickup lens 27a in the present embodiment is configured such that the maximum incident angle β is less than 60 °. Thereby, total reflection of incident light on the light incident surface 27A is suppressed, and most of the light emitted from the phosphor layer 32 can be incident on the first pickup lens 27a.

  On the other hand, when the plano-convex lens 57 is used as shown in FIG. 9B, the light incident surface 57A of the plano-convex lens 57 is arranged in parallel with the light exit surface 32A of the phosphor layer 32. Therefore, the maximum incident angle β ′ to the plano-convex lens 57 is about 80 °, and Fresnel loss is likely to occur.

  From the above, in the present embodiment, a meniscus lens having a light incident surface 27A as a concave surface is used as the first pickup lens 27a disposed to face the phosphor layer 32.

The projector 1 in this embodiment includes the light source device 2 as described above. The light source device 2 in this embodiment is particularly characterized by the fluorescent light emitting element 28 and the first pickup lens 27a.
As described above, as the first pickup lens 27a, a meniscus lens in which the light incident surface 27A facing the phosphor layer 32 forms a concave surface is used. On the other hand, in the fluorescent light emitting element 28, the convex portion 36 that holds the phosphor layer 32 has an inclined surface 36c along the concave surface of the light incident surface 27A of the first pickup lens 27a. As a result, a space 38 having a predetermined thickness is formed between the convex portion 36 and the first pickup lens 27a. By forming the inclined surface 36c of the convex portion 36 and the light incident surface 27A of the first pickup lens 27a to have a similar curved shape, there is no space 38 (channel) where there is no air stagnation between them. Is formed.
Further, since the convex portion 36 and the first pickup lens 27a having a circular shape in plan view are arranged coaxially, the space 38 is uniformly formed around the optical axis ax2, and the space 38 becomes extremely narrow. Nor.

  With such a configuration, it is possible to effectively cool the phosphor layer 32 (in particular, the light emission surface 32A side) that generates heat by smoothly flowing air in the space 38. Moreover, since the surface area of the convex portion 36 made of pure copper is increased by providing the inclined surface 36 c on the convex portion 36 that holds the phosphor layer 32, it is possible to enhance the heat dissipation effect on the phosphor layer 32.

  In the present embodiment, a meniscus lens having a concave light incident surface 27A is used as the first pickup lens 27a so that the maximum incident angle of light incident on the light incident surface 27A is less than 60 °. It is configured. Thereby, the total reflection of the light beam on the light incident surface 27A is suppressed, and the incident efficiency of the light emitted from the phosphor layer 32 can be increased.

  Thus, the projector 1 with high reliability can be obtained by including the light source device 2 that is excellent in the efficiency of capturing light from the phosphor layer 32 with respect to the first pickup lens 27a and has high cooling efficiency with respect to the phosphor layer 32. .

[Second Embodiment]
Next, the configuration of the light source device in the second embodiment will be described.
The basic configuration of the light source device in the present embodiment is substantially the same as that in the first embodiment, but differs in the configuration of the first pickup lens. Therefore, in the following description, the configuration of the first pickup lens will be described in detail, and description of common parts will be omitted. Moreover, in each drawing used for description, the same code | symbol shall be attached | subjected to the same component as FIGS.

FIG. 10 is a diagram showing a configuration of the first pickup lens provided with the antireflection film in the second embodiment.
As shown in FIG. 10, an antireflection film 39 made of an AR (Anti Reflect) coat film is provided on the light incident surface 27A of the first pickup lens 27a of the present embodiment as an example of an antireflection structure.

Examples of the antireflection film 39 include an MgF ₂ film, a Ta ₂ O ₅ film, and a SiO ₂ multilayer film, and can be formed using a known vapor deposition process. The antireflection film 39 is adjusted to match the emission wavelength of the phosphor layer 32. Thereby, it is possible to prevent the light emitted from the phosphor layer 32 from being reflected on the light incident surface 27A of the first pickup lens 27a, and to reduce the loss of light when entering the first pickup lens 27a. .

Next, the reason why the maximum incident angle of light from the center of the phosphor layer 32 to the first pickup lens 27a is less than 60 ° will be described.
FIG. 11 is a diagram showing the reflection characteristics when a conventional antireflection film is formed on a glass substrate (nd = 1.723). However, in FIG. 11, the straight line (a), the straight line (b), and the straight line (c) are reflection characteristics when the antireflection film is not formed. The straight line (a) is a reflection characteristic with respect to incident light having an incident angle of 60 °, the straight line (b) is a reflection characteristic with respect to incident light having an incident angle of 70 °, and the straight line (c) is incident with an incident angle of 80 °. This is a reflection characteristic for light.

As shown in FIG. 11, when the incident angle of incident light is in the range of 0 ° to less than 60 °, the reflectance is about 3% or less in a wide wavelength region within the visible region.
On the other hand, when the incident angle is 60 ° or more, the reflectance suddenly increases. For example, the reflectance in the wavelength range of 400 nm to 700 nm is about 3 to 4% at an incident angle of 60 °, about 10 to 20% at an incident angle of 70 °, and about 30 to 42% at an incident angle of 80 °.

Compared with the case where the antireflection film 39 is not formed, by forming the antireflection film 39, the reflectance with respect to incident light having an incident angle of 60 ° to 80 ° can be reduced by about 10%.
However, the reflectivity for incident light with an incident angle of 60 ° or more and 80 ° or less is significantly larger than the reflectivity for light with an incident angle of less than 60 °.

  Therefore, in this embodiment, the curvature of the light incident surface 27A is set so that the light incident on the first pickup lens 27a has an incident angle of less than 60 °. The light incident rate of the light emitted from the phosphor layer 32 with respect to the first pickup lens 27a is expected to be approximately 90% or more, and the antireflection film 39 is applied to the light incident surface 27A of the first pickup lens 27a. Is expected to have a transmittance of 95% or more.

  Next, when a meniscus lens is provided as the first pickup lens 27a (hereinafter, the first pickup lens 27a may be referred to as a meniscus lens 27a), and a plano-convex lens 57 as shown in FIG. A comparison of the incident efficiency with the case where it is provided will be described. Here, when no antireflection film is provided on the light incident surface of each lens, when a single-layer antireflection film is provided, and when a three-layer antireflection film is provided, the difference in reflectance of incident light in each case Is also explained.

First, the incidence efficiency in a state where the anti-reflection treatment is not applied to each light incident surface of the meniscus lens and the plano-convex lens will be described.
In this case, the incident efficiency of light on the light incident surface 57A of the plano-convex lens 57 is 67.73%, whereas the incident efficiency of light on the light incident surface 27A of the meniscus lens 27a is 72.55%. The incident efficiency of 27a is approximately 1.07 times the incident efficiency of the plano-convex lens 57.

Next, the incident efficiency of each light when a single-layer AR coating is applied to the light incident surface of each lens will be described.
In this case, the light incident efficiency on the light incident surface 57A of the plano-convex lens 57 provided with the single-layer AR coating was 92.25%. On the other hand, the incident efficiency of light on the light incident surface 27A of the meniscus lens 27a provided with the single-layer AR coating is 95.93%, and the incident efficiency of the meniscus lens is about 1.04 times the incident efficiency of the plano-convex lens 57. is there.

Next, the incident efficiency of each light when the AR coating composed of a multilayer film of three layers is applied to the light incident end face of each lens will be described.
Here, as the AR coating film having a three-layer structure, an SiO ₂ film, a ZrO ₂ film, and an MgF ₂ film were laminated in this order on the light incident surface. Details of each layer are, for example, SiO ₂ film (refractive index: 1.7, thickness: 80.88 nm), ZrO ₂ film (refractive index: 2.1, thickness: 130.95 nm), MgF ₂ film (refractive index: 1.38, thickness: 99.64 nm).

  In this case, the incident efficiency of light on the light incident surface 57A of the plano-convex lens 57 to which the AR coating made of the multilayer film is applied is 93.23%, whereas the meniscus lens to which the AR coating made of the multilayer film is applied. The incident efficiency of light on the light incident surface 27A of 27a is 97.22%, and the incident efficiency of the meniscus lens is about 1.04 times the incident efficiency of the plano-convex lens 57.

  From the above, the light incident efficiency is greatly improved by using a meniscus lens having a concave surface instead of the conventional plano-convex lens 57 as the first pickup lens 27a for making the light from the phosphor layer 32 incident. Further, by providing an antireflection film on the light incident surface 27A, it is possible to further improve the incident efficiency. At this time, it is possible to sufficiently increase the light incidence efficiency even with a single-layer antireflection film, but by providing an antireflection film composed of a three-layer multilayer film, all incident light on the light incident surface 27A can be obtained. The reflection is further suppressed, and more light can be taken into the first pickup lens 27a.

  The AR coating described above is an example of an antireflection structure, and another antireflection structure may be applied to the first pickup lens 27a (light incident surface 27A). For example, as shown in FIG. 12, a moth-eye sheet 40 or the like in which a plurality of fine conical protrusions 40a are periodically arranged may be provided on the light incident surface 27A.

  As in the present embodiment, by providing the antireflection film 39 on the light incident surface 27A of the first pickup lens 27a, reflection of light on the light incident surface 27A can be further prevented, and radiation from the phosphor layer 32 can be achieved. The incident efficiency of the emitted light can be further increased.

[Third Embodiment]
Next, the configuration of the light source device in the third embodiment will be described.
The basic configuration of the light source device in the present embodiment is substantially the same as that of the first embodiment, but differs in the shape of the convex portion that holds the phosphor layer 32. Therefore, in the following description, the configuration of the convex portion will be described in detail, and description of common portions will be omitted. Moreover, in each drawing used for description, the same code | symbol shall be attached | subjected to the same component as FIGS.

FIG. 13 is a diagram illustrating an example of the shape of the protrusions in the fluorescent light emitting device according to the third embodiment.
As shown in FIG. 13, the convex portion 41 in the present embodiment has a conical shape in which an inclined surface 41 c that connects the bottom surface 41 b of the convex portion 41 and the flat surface 41 a is not curved in the radial direction.
Even in such a configuration, air smoothly flows in the space 38 formed between the inclined surface 41c of the convex portion 41 and the light incident surface 27A of the first pickup lens 27a. It can be cooled efficiently.

[Fourth Embodiment]
Next, the configuration of the light source device in the fourth embodiment will be described.
The basic configuration of the light source device in the present embodiment is substantially the same as that of the first embodiment, but differs in the shape of the convex portion that holds the phosphor layer 32. Therefore, in the following description, the configuration of the convex portion will be described in detail, and description of common portions will be omitted. Moreover, in each drawing used for description, the same code | symbol shall be attached | subjected to the same component as FIGS.

FIG. 14 is a diagram showing an example of the shape of the convex portion in the fluorescent light emitting device in the fourth embodiment.
As shown in FIG. 14, the convex portion 42 in the present embodiment is not provided with a flat surface (a flat surface parallel to the bottom surface 42b) facing the light incident surface 27A of the first pickup lens 27a on the surface thereof. The entire surface has an inclined surface 42c that is curved. The phosphor layer 32 is provided on the top of the inclined surface 42c (the portion farthest from the bottom surface 42b), and is entirely curved following the shape of the inclined surface 42c.

  Even in such a configuration, air smoothly flows in the space 38 formed between the inclined surface 42c of the convex portion 42 and the light incident surface 27A of the first pickup lens 27a, and the phosphor layer 32 is It can be cooled efficiently.

[Fifth Embodiment]
Next, the configuration of the light source device in the fifth embodiment will be described.
The basic configuration of the light source device in the present embodiment is substantially the same as that of the first embodiment, but differs in the shape of the convex portion that holds the phosphor layer 32. Therefore, in the following description, the configuration of the convex portion will be described in detail, and description of common portions will be omitted. Moreover, in each drawing used for description, the same code | symbol shall be attached | subjected to the same component as FIGS.

FIG. 15 is a diagram illustrating an example of the shape of the protrusions in the fluorescent light emitting device according to the fifth embodiment.
As shown in FIG. 15, the convex portion 43 in the present embodiment has a cylindrical shape as a whole, and has a shape having an inclined surface 43 c that chamfers the peripheral portion of the flat surface 43 a. By providing the inclined surface 43c around the flat surface 43a holding the phosphor layer 32, the inside of the space 38 formed between the inclined surface 43c of the convex portion 43 and the light incident surface 27A of the first pickup lens 27a is formed. The air flows smoothly, and the phosphor layer 32 can be efficiently cooled.
Moreover, since the surface area of the convex part 43 increases by providing the inclined surface 43c, compared with the case where it is only a cylindrical shape, the heat dissipation effect is improved.

  As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  The shape of the convex portion in the fluorescent light emitting element is not limited to the above-described shape, and may be another shape.

  DESCRIPTION OF SYMBOLS 1 ... Projector, 2 ... Light source device (illuminating device), 36c, 41c, 42c, 43c ... Inclined surface, 11 ... End surface, 21 ... Array light source (light source), 27A, 57A ... Light incident surface, 27B ... Edge, 27c ... Third pickup lens, meniscus lens, 32 ... phosphor layer, 32A ... light emission surface, 35 ... holding substrate (substrate), 35a ... first surface, 36, 41, 42, 43 ... convex portion, 36a ... flat surface ( End face), YL ... yellow light, fluorescent light (light in the second wavelength band), BLc2 ... light (light in the first wavelength band)

Claims (11)

A light source;
A substrate having a first surface;
A convex portion provided on the first surface and having an inclined surface inclined with respect to the first surface;
A phosphor that is provided on the convex portion and is excited by light of the first wavelength band emitted from the light source to generate light of a second wavelength band different from the light of the first wavelength band Layers,
A meniscus lens disposed on the opposite side of the convex portion of the phosphor layer and having a concave light incident surface facing the light emission surface of the phosphor layer ,
The inclined surface is a light source device characterized that you have curved so as to follow the curvature of the light incident surface of the meniscus lens.   The light source device according to claim 1, wherein the meniscus lens is configured such that a maximum incident angle of a light beam from a center of the phosphor layer to the light incident surface is less than 60 °. The convex portion has a flat surface,
The light source device according to claim 1, wherein the phosphor layer is provided on the flat surface.   The light source device according to claim 1, wherein the phosphor layer is provided on the inclined surface.   5. The meniscus lens has an end surface that intersects the optical axis of the meniscus lens outside the light incident surface, and the end surface is located on the substrate side with respect to the phosphor layer. The light source device according to any one of the above.   The light source device according to claim 1, wherein the light incident surface of the meniscus lens includes an antireflection structure. The convex portion has a circular shape in plan view,
The light source device according to claim 1, wherein the convex portion and the meniscus lens are coaxially arranged.   The light source device according to claim 1, wherein the convex portion and the substrate are integrally formed.   The light source device according to claim 1, wherein the convex portion is made of copper.   The light source device according to claim 1, wherein a planar shape of the phosphor layer is rectangular. An illumination device for illuminating illumination light;
A light modulation device that modulates the illumination light according to image information to form image light;
A projection optical system for projecting the image light,
11. A projector using the light source device according to claim 1 as the illumination device.

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