LIGHT SOURCE DEVICE AND PROJECTOR

A light source device includes a first laser emitter configured to emit first light, a light transmissive member having a first surface and a second surface, the first light emitted from the first laser emitter being incident on the second surface, a base having a first support part configured to support the first laser emitter and a second support part configured to support the light transmissive member, and a wavelength converter arranged on the first surface and configured to convert the first light into second light. The wavelength converter has an incident surface including an incident area where the first light enters and an emission surface disposed at an opposite side to the incident surface and configured to emit the second light. The second support part supports the second surface of the light transmissive member in an area corresponding to the incident area.

The present application is based on, and claims priority from JP Application Serial Number 2022-052359, filed Mar. 28, 2022, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

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

2. Related Art

In the past, there has been a light source device which makes excitation light emitted from a laser element enter a wavelength converter from a reverse surface, and then emits fluorescence generated by the wavelength converter from an obverse surface of the wavelength converter (see, e.g., JP-A-2021-106299). In this light source device, a periphery of a transparent radiator substrate provided with the wavelength converter is supported with a radiator member shaped like a frame. The heat of the wavelength converter is released to the radiator member via a light transmissive member.

However, in the light source device described above, since a radiation path from the wavelength converter to the radiation member is long, there is a problem that the temperature of the wavelength converter rises to thereby deteriorate luminous efficiency.

SUMMARY

In view of the problems described above, a light source device according to the present disclosure includes a first laser emitter configured to emit first light in a first wavelength band, a light transmissive member having a first surface and a second surface opposite to the first surface, the first light emitted from the first laser emitter being incident on the second surface, a base having a first support part configured to support the first laser emitter, and a second support part configured to support the light transmissive member, and a wavelength converter arranged on the first surface of the light transmissive member and configured to convert the first light into second light in a second wavelength band different from the first wavelength band. The wavelength converter has an incident surface including an incident area where the first light enters and an emission surface disposed at an opposite side to the incident surface and configured to emit the second light. The second support part supports the second surface of the light transmissive member in an area corresponding to the incident area.

A projector according to the present disclosure includes the light source device described above, a light modulation device configured to modulate the light emitted from the light source device, and a projection optical device configured to project the light modulated by the light modulation device.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Some embodiments of the present disclosure will hereinafter be described in detail with reference to the drawings.

It should be noted that the drawings used in the following description show characteristic parts in an enlarged manner in some cases for the sake of convenience in order to make the features easy to understand, and the dimensional ratios between the constituents and so on are not necessarily the same as actual ones.

First Embodiment

An example of a projector according to the present embodiment will be described.

FIG.1is a diagram showing a schematic configuration of the projector according to the present embodiment.

As shown inFIG.1, the projector1according to the present embodiment is a projection-type image display device for displaying a color image on a screen SCR. The projector1is provided with a color separation optical system3, a light modulation device4R, a light modulation device4G, a light modulation device4B, a combining optical system5, a projection optical device6, and an illumination device2.

The color separation optical system3separates illumination light WL having a white color from the illumination device2into red light LR, green light LG, and blue light LB. The color separation optical system3is provided with a first dichroic mirror7aand a second dichroic mirror7b, a first reflecting mirror8a, a second reflecting mirror8b, and a third reflecting mirror8c, and a first relay lens9aand a second relay lens9b.

The first dichroic mirror7aseparates the illumination light WL from the illumination device2into the red light LR and the rest of the light, namely the green light LG and the blue light LB. The first dichroic mirror7atransmits the red light LR separated, and at the same time, reflects the rest of the light. The second dichroic mirror7breflects the green light LG, and at the same time, transmits the blue light LB.

The first reflecting mirror8areflects the red light LR toward the light modulation device4R. The second reflecting mirror8band the third reflecting mirror8cguide the blue light LB to the light modulation device4B. The green light LG is reflected by the second dichroic mirror7btoward the light modulation device4G.

The first relay lens9ais disposed in a posterior stage of the second dichroic mirror7bin the light path of the blue light LB. The second relay lens9bis disposed in a posterior stage of the second reflecting mirror8bin the light path of the blue light LB.

The light modulation device4R modulates the red light LR in accordance with image information to form image light corresponding to the red light LR. The light modulation device4G modulates the green light LG in accordance with the image information to form image light corresponding to the green light LG. The light modulation device4B modulates the blue light LB in accordance with the image information to form image light corresponding to the blue light LB.

As the light modulation device4R, the light modulation device4G, and the light modulation device4B, there are used, for example, transmissive liquid crystal panels. Further, at the incident side and the exit side of the liquid crystal panel, there are respectively disposed polarization plates not shown, and thus, there is formed the configuration of transmitting only the linearly-polarized light having a specific direction.

At the incident side of the light modulation device4R, the light modulation device4G, and the light modulation device4B, there are disposed a field lens10R, a field lens10G, and a field lens10B, respectively. The field lens10R, the field lens10G, and the field lens10B collimate the principal rays of the red light LR, the green light LG, and the blue light LB which enter the light modulation device4R, the light modulation device4G, and the light modulation device4B, respectively.

The combining optical system5combines the image light corresponding to the red light LR, the image light corresponding to the green light LG, and the image light corresponding to the blue light LB with each other in response to incidence of the image light respectively emitted from the light modulation device4R, the light modulation device4G, and the light modulation device4B, and then emits the image light thus synthesized toward the projection optical device6. As the combining optical system5, there is used, for example, a cross dichroic prism.

The projection optical device6is constituted by a plurality of lenses. The projection optical device6projects the image light having been synthesized by the combining optical system5toward the screen SCR in an enlarged manner. Thus, an image is displayed on the screen SCR.

Illumination Device

FIG.2is a schematic configuration diagram of the illumination device2.

As shown inFIG.2, the illumination device2is provided with a light source device20, a pickup optical system34, an integrator optical system35, a polarization converter36, and a superimposing lens37.

The light source device20emits the illumination light WL having a white color toward the pickup optical system34.

The pickup optical system34is constituted by, for example, pickup lenses34a,34b. The pickup optical system34has a function of picking up and then collimating the illumination light WL emitted from the light source device20.

The illumination light WL collimated by the pickup optical system34enters the integrator optical system35. The integrator optical system35is constituted by, for example, a first lens array35aand a second lens array35b.

The first lens array35aincludes a plurality of first small lenses35am, and the second lens array35bincludes a plurality of second small lenses35bm.

The first lens array35aseparates the illumination light WL into a plurality of small pencils. The first small lenses35amform images of the small pencils on the corresponding second small lenses35bm, respectively. The integrator optical system35cooperates with the superimposing lens37described later to thereby homogenize an illuminance distribution of each of the image formation areas of the light modulation devices4R,4G shown inFIG.1as the illumination target areas.

The illumination light WL having passed through the integrator optical system35enters the polarization converter36. The polarization converter36is constituted by, for example, a polarization separation film and a retardation plate (a ½ wave plate). The polarization converter36converts a polarization direction in fluorescence YL into one polarization component.

The illumination light WL having passed through the polarization converter36enters the superimposing lens37. The illumination light WL having been emitted from the superimposing lens37enters the color separation optical system3. The superimposing lens37superimposes the plurality of small pencils described above forming the illumination light WL on each other in illumination target areas, namely image formation areas, of the light modulation devices4R,4G to thereby homogenously illuminate the image formation areas.

A configuration of the light source device20will hereinafter be described in detail. In the following drawings, each of the constituents of the light source device20will be described using an XYZ coordinate system as needed. The Z axis is an axis parallel to an optical axis ax of the light source device20, the X axis is an axis which is perpendicular to the optical axis ax, and is parallel to a normal line of a base21constituting the light source device20, and the Y axis and the Z axis are axes which are perpendicular to each other, and are perpendicular to the X axis. It should be noted that the optical axis ax of the light source device20coincides with an illumination light axis ax1of the illumination device2shown inFIG.2.

FIG.3is a plan view of the light source device20.FIG.3is a diagram of the light source device20viewed from a direction (the Z-axis direction) along the optical axis ax.

As shown inFIG.3, the light source device20is provided with the base21, a plurality of laser emitters22, a wavelength converter24, and a light transmissive member25.

The base21supports the plurality of laser emitters22, the wavelength converter24, and the light transmissive member25. The base21is a metal plate excellent in radiation performance made of, for example, aluminum or copper.

When making a plan view viewed from the Z-axis direction along the optical axis ax (hereinafter simply referred to as a plan view), the plurality of laser emitters22is arranged in a circumferential direction around the optical axis ax. In the case of the present embodiment, the plurality of laser emitters22includes eight laser emitters22. The plurality of laser emitters22is arranged so that a pair of elements are opposed to each other across the optical axis ax.

In the present embodiment, the plurality of laser emitters22includes a first laser emitter22aand a second laser emitter22b. The first laser emitter22aand the second laser emitter22bare arranged on the base21so as to be opposed to each other across the optical axis ax. The first laser emitter22ais arranged at a −Y side with respect to the optical axis ax, and the second laser emitter22bis arranged at a +Y side with respect to the optical axis ax.

The first laser emitter22aand the second laser emitter22bare hereinafter simply referred to as the laser emitters22in some cases when being not discriminated from the rest of the laser emitters.

FIG.4is a cross-sectional view of the light source device20.FIG.4is a cross-sectional view according to an arrow view along the line IV-IV inFIG.3, and is a cross-sectional view of the light source device20along a plane which includes the optical axis ax and is perpendicular to an X-Y plane. It should be noted thatFIG.4is a cross-sectional view along a plane including the first laser emitter22aand the second laser emitter22bout of the plurality of laser emitters22. InFIG.4, in order to simplify the description, only the principal rays are illustrated with respect to excitation light E emitted from the first laser emitter22aand the second laser emitter22b.

As shown inFIG.3andFIG.4, the base21has a first support part210for supporting the plurality of laser emitters22including the first laser emitter22aand the second laser emitter22b, and a second support part211for supporting the light transmissive member25.

Each of the laser emitters22is thermally coupled to the base21via the first support part210, and the light transmissive member25is thermally coupled to the base21via the second support part211. In other words, the base21functions as a radiator member for releasing the heat of the laser emitters22and the light transmissive member25.

The base21has a base part212and a protruding part213. The base part212is a plate-like region. The protruding part213is a region protruding from one surface212aof the base part212. The protruding part213of the base21has a polygonal outer shape such as an octagonal outer shape in the plan view. The protruding part213is configured by chamfering an apex of an eight-sided pyramid. The protruding part213has eight side surfaces213aeach having a trapezoidal shape, and a top surface213bhaving an octagonal shape.

On the side surfaces213aof the protruding part213, there are respectively arranged the laser emitters22. The side surfaces213aof the protruding part213constitute the first support part210for supporting the plurality of laser emitters including the first laser emitter22aand the second laser emitter22b. On the top surface213bof the protruding part213, there is arranged the light transmissive member25. In the present embodiment, the protruding part213constitutes a second support part211for supporting the light transmissive member25.

The laser emitters22each include the light emitting part220and a sub-mount221. The light emitting part220emits the excitation light (first light) E in a first wavelength band. The first wavelength band is, for example, a wavelength band from a blue color to a violet color of 400 nm through 480 nm, and has a peak wavelength of, for example, 455 nm.

The sub-mounts221are each formed of a ceramic material such as aluminum nitride or alumina. The sub-mounts221each relax a thermal stress caused by a difference in linear expansion coefficient between the base21and the light emitting part220. The sub-mounts221are each bonded to the first support part210(the side surface213a) of the base21with a bonding material such as a silver brazing material or gold-tin solder.

The light transmissive member25is arranged at a light exit side of the laser emitters22. The light transmissive member25has a circular shape in the plan view. The light transmissive member25is a plate-like member having an obverse surface (a first surface)25aand a reverse surface (a second surface)25bopposite to the obverse surface25a. A part of the reverse surface25bof the light transmissive member25is supported by the second support part211(the top surface213b) of the base21.

As a material forming the light transmissive member25, there can be cited glass such as borosilicate glass, quartz glass, or quart glass, quartz crystal, sapphire, and so on. It should be noted that it is possible to form the light transmissive member25from a high thermal conductive member such as sapphire to thereby make the light transmissive member25function as a radiator member for releasing the heat of the wavelength converter24.

The base21and the light transmissive member25are bonded to each other with a bonding material such as an organic adhesive, a metal bonding material, or an inorganic bonding material. As the organic adhesive, there is preferably used, for example, a silicone-based adhesive, an epoxy resin-based adhesive, or an acrylic resin-based adhesive. As the metal bonding material, there is preferably used, for example, a silver brazing material or gold-tin solder. As the inorganic bonding material, there is preferably used, for example, low-melting-point glass.

The reverse surface25bof the light transmissive member25is opposed to the light exit surface of each of the laser emitters22in an area different from an area where the light transmissive member25is supported by the second support part211. Therefore, the excitation light E emitted from each of the laser emitters22enters the reverse surface25bof the light transmissive member25.

On the obverse surface25aof the light transmissive member25, there is arranged the wavelength converter24.

The wavelength converter24has a plane of incidence24aincluding an incident area SP which the excitation light E enters, and an exit surface24bfor emitting the fluorescence YL. In the wavelength converter24in the present embodiment, the exit surface24bis a surface disposed at an opposite side to the plane of incidence24a. In other words, the wavelength converter24in the present embodiment is a so-called transmissive wavelength converter which emits light from the exit surface24bopposite to the plane of incidence24aalong an incident direction of the excitation light E to the plane of incidence24a.

In the light source device20according to the present embodiment, an uneven structure26is formed on the plane of incidence24aof the wavelength converter24. The uneven structure26has contact with the obverse surface25aof the light transmissive member25. Thus, it is possible to provide fine gaps between the plane of incidence24aof the wavelength converter24and the obverse surface25aof the light transmissive member25without using a member such as a spacer. An air layer exists in the fine gap. In other words, in the present embodiment, the air layer A is disposed between the plane of incidence24aof the wavelength converter24and the obverse surface25aof the light transmissive member25. Specifically, the air layer A is provided to the uneven structure26formed on the plane of incidence24aof the wavelength converter24. Such an uneven structure26is formed by performing, for example, a sandblast treatment on the plane of incidence24a.

It should be noted that although there is cited when forming the uneven structure26on the plane of incidence24aof the wavelength converter24to thereby dispose the air layer A between the plane of incidence24aof the wavelength converter24and the obverse surface25aof the light transmissive member25as an example in the present embodiment, it is possible to dispose an air layer in an uneven structure formed in an area opposed to the plane of incidence24ain the obverse surface25aof the light transmissive member25.

The wavelength converter24includes a phosphor for converting the excitation light E into the fluorescence (second light) YL in a second wavelength band different from the first wavelength band. The second wavelength band is a yellow wavelength band of, for example, 550 through 640 nm. As such a phosphor, there can be used, for example, a YAG (yttrium aluminum garnet) based phosphor. It should be noted that the constituent material of the phosphor can be unique, or it is also possible to use a mixture of the particles formed using two or more types of materials as the phosphor.

Then, there will be described when emitting the illumination light WL from the light source device20according to the present embodiment.

First, the excitation light E is emitted from each of the laser emitters22arranged so as to surround the periphery of the wavelength converter24toward the reverse surface25bof the light transmissive member25. It should be noted that the excitation light E emitted from each of the laser emitters22exhibits the same behavior in the light transmissive member25. Therefore, the description will hereinafter be presented citing the behavior of the excitation light E emitted from the first laser emitter22aas an example.

The first laser emitter22aemits the excitation light E toward the reverse surface25bof the light transmissive member25. The first laser emitter22aemits the excitation light E in an oblique direction with respect to the reverse surface25bof the light transmissive member25. When the excitation light E enters the reverse surface25bof the light transmissive member25, the excitation light E is refracted and then enters wavelength converter24disposed on the obverse surface25aof the light transmissive member25. It should be noted that inFIG.4, in order to make the drawing eye-friendly, the refraction of the excitation light E is not expressed, but the excitation light E is shown as if being transmitted straight through the reverse surface25b.

Here, when the excitation light E obliquely enters the wavelength converter24, there is a possibility that the light intensity of the excitation light E reflected by the surface of the wavelength converter24increases. Such excitation light E as being reflected by the surface of the wavelength converter24is high in deviation of the angular characteristic, and is high in probability of becoming stray light which is not available as the illumination light. Further, the stray light component is absorbed by other optical members and so on in the device to thereby cause a local rise in temperature to become a cause breakage in some cases.

In contrast, in the wavelength converter24in the present embodiment, by scattering the excitation light E with the uneven structure26formed on the plane of incidence24aof the wavelength converter24, it is possible to suppress the light intensity of the excitation light E to be reflected by the surface of the plane of incidence24a. Further, since the excitation light E is scattered by the uneven structure26to suppress the deviation of the angular characteristic even when the excitation light E is supposedly reflected by the plane of incidence24a, it is possible to prevent an occurrence of a problem such as a deterioration of a light use efficiency and heat generation due to the stray light.

FIG.5is a cross-sectional view showing a configuration of an essential part of the wavelength converter24.

As shown inFIG.5, the wavelength converter24emits, from the exit surface24b, the illumination light WL having a white color and including the fluorescence YL obtained by performing the wavelength conversion on the excitation light E entering the wavelength converter24from the plane of incidence24aand a part of the excitation light E not converted into the fluorescence.

A part of the fluorescence YL proceeds toward the plane of incidence24aof the wavelength converter24. In the case of the present embodiment, it is possible to reflect the fluorescence YL toward the exit surface24bby the air layer A disposed between the plane of incidence24aof the wavelength converter24and the obverse surface25aof the light transmissive member25.

In the present embodiment, it is preferable to make the contact area between the plane of incidence24aof the wavelength converter24and the obverse surface25aof the light transmissive member25as small as possible. When the contact area between the plane of incidence24aand the obverse surface25adecreases, the surface area of the air layer A having contact with the plane of incidence24aincreases. When the surface area of the air layer A having contact with the plane of incidence24aincreases as described above, the total reflection of the fluorescence YL by an interface between the air layer A described above and the plane of incidence24abecomes more apt to occur. Therefore, it is possible to more efficiently take out the fluorescence YL as the illumination light WL.

In the light source device20according to the present embodiment, the wavelength converter24generates heat when generating the excitation light E. In the case of the present embodiment, it is preferable to make the thickness of the air layer A as thin as possible. In other words, it is preferable to make the depth of the unevenness of the uneven structure26shallower. Since the thinner the air layer A is made as described above, the easier it becomes to transfer the heat of the wavelength converter24toward the light transmissive member25, the performance of cooling the wavelength converter24is enhanced.

In the present embodiment, as shown inFIG.4, the top surface213bof the protruding part213forming the second support part211supports an area corresponding to the incident area SP out of the reverse surface25bof the light transmissive member25. The top surface213bof the protruding part213is a support surface for supporting the light transmissive member25in the second support part211.

In the present embodiment, the area corresponding to the incident area SP out of the reverse surface25bmeans an area overlapping the incident area SP of the excitation light E in the plan view in the plane of incidence24aof the wavelength converter24out of the reverse surface25bwhen making the plan view. Generally, the excitation light E enters a part of the plane of incidence24a, the area of the incident area SP becomes smaller than the area of the plane of incidence24a.

In the wavelength converter24, the temperature becomes the highest in the incident area SP out of the plane of incidence24a. Therefore, in the light transmissive member25, the temperature on the obverse surface25aopposed to the incident area SP of the wavelength converter24becomes the highest, and the heat of the obverse surface25ais transferred to an area opposed to the incident area SP out of the reverse surface25b.

As shown inFIG.4, in the light source device20according to the present embodiment, the reverse surface25bin a portion corresponding to the incident area SP which becomes the highest in temperature in the obverse surface25ais supported by the second support part211of the base21. Further, in the case of the present embodiment, the area of a support surface (the top surface213b) of the light transmissive member25in the second support part211is larger than the area of the incident area SP of the wavelength converter24. Therefore, since the heat of the wavelength converter24is efficiently transferred to the base21via the light transmissive member25, it is possible to further enhance the performance of cooling the wavelength converter24.

In such a manner, the light source device20emits the illumination light WL having a white color including a part of the excitation light E and the fluorescence YL from the exit surface24bof the wavelength converter24.

According to the light source device20related to the present embodiment described hereinabove, the following advantages are exerted.

The light source device20according to the present embodiment is provided with the plurality of laser emitters22including the first laser emitter22afor emitting the excitation light E, the light transmissive member25which has the obverse surface25aand the reverse surface25b, and the reverse surface25bwhich the excitation light E emitted from the first laser emitter22aenters, the base21having the first support part210for supporting the first laser emitter22aand the second support part211for supporting the light transmissive member25, and the wavelength converter24which is arranged on the obverse surface25aof the light transmissive member25, and which converts the excitation light E into the fluorescence YL in the yellow wavelength band. The wavelength converter24has the plane of incidence24aincluding the incident area SP which the excitation light E enters, and the exit surface24bwhich is disposed at an opposite side to the plane of incidence24a, and which emits the fluorescence YL. The second support part211supports the area corresponding to the incident area SP out of the reverse surface25bof the light transmissive member25.

In the light source device20according to the present embodiment, the reverse surface25bof the light transmissive member25corresponding to the incident area SP which becomes the highest in temperature in the plane of incidence24aof the wavelength converter24is supported by the base21. Therefore, the heat having been transferred from the incident area SP of the wavelength converter24toward the reverse surface25bof the light transmissive member25can efficiently be released from the second support part211of the base21. Therefore, since the rise in temperature of the wavelength converter24is suppressed, and thus the fluorescence conversion efficiency increases, it is possible to take out the fluorescence YL high in luminance as the illumination light WL.

In the light source device20according to the present embodiment, the air layer A is disposed between the plane of incidence24aof the wavelength converter24and the obverse surface25aof the light transmissive member25.

According to this configuration, due to the air layer A disposed between the plane of incidence24aof the wavelength converter24and the obverse surface25aof the light transmissive member25, it is possible to reflect the fluorescence YL proceeding toward the plane of incidence24ainside the wavelength converter24to emit the fluorescence YL from the exit surface24b. Thus, it is possible to increase the intensity of the fluorescence YL taken out as the illumination light WL.

In the light source device20according to the present embodiment, the uneven structure26is formed on the plane of incidence24aof the wavelength converter24, and the air layer A is provided to the uneven structure26.

According to this configuration, by using the uneven structure26formed on the plane of incidence24a, it is possible to easily realize the configuration of disposing the air layer A between the plane of incidence24aof the wavelength converter24and the obverse surface25aof the light transmissive member25.

In the light source device20according to the present embodiment, the second support part211has the top surface213bfor supporting the reverse surface25bof the light transmissive member25, and the area of the top surface213bis larger than the area of the incident area SP of the wavelength converter24.

According to this configuration, since it is possible to efficiently release the heat from the wavelength converter24to the base21, it is possible to further enhance the performance of cooling the wavelength converter24. Thus, it is possible to take out the fluorescence YL higher in luminance as the illumination light WL by increasing the fluorescence conversion efficiency of the wavelength converter24.

According to the projector1related to the present embodiment described hereinabove, the following advantages are exerted.

The projector1according to the present embodiment is provided with the light source device20, the light modulation devices4B,4G, and4R, and the projection optical device6, wherein the light modulation devices4B,4G, and4R modulate the blue light LB, the green light LG, and the red light LR from the light source device20to thereby form the image light, and the projection optical device6projects the image light described above.

According to the projector1related to the present embodiment, since there is provided the light source device20for generating the illumination light WL including the fluorescence YL high in luminance, it is possible to form and then project an image high in luminance.

Second Embodiment

Then, a configuration of a light source device according to a second embodiment of the present disclosure will be described. It should be noted that in the present embodiment, constituents or members common to the first embodiment will be denoted by the same reference symbols, and the detailed description thereof will be omitted.

FIG.6is a diagram showing the configuration of the light source device according to the present embodiment.

As shown inFIG.6, the light source device200according to the present embodiment is provided with the base21, the plurality of laser emitters22, a wavelength converter124, the light transmissive member25, a spacer27, a first reflector28, and a second reflector29.

In the light source device200according to the present embodiment, the wavelength converter124is disposed on the obverse surface25aof the light transmissive member25via the spacer27. In other words, the spacer27is disposed between a plane of incidence124aof the wavelength converter124and the obverse surface25aof the light transmissive member25. No uneven structure is formed on the plane of incidence124aof the wavelength converter124in the present embodiment. Therefore, the plane of incidence124ais formed of a flat surface.

It should be noted that the spacer27is disposed at a position where the spacer27does not overlap the incident area SP which the excitation light E enters in the plane of incidence124aof the wavelength converter124. Further, by using a high thermal conductive material such as metal or ceramics as the material of the spacer27, it is possible to release the heat of the wavelength converter24to the light transmissive member25via the spacer27.

In the present embodiment, the air layer A is disposed between the plane of incidence124aof the wavelength converter124and the obverse surface25aof the light transmissive member25. Specifically, the air layer A is disposed in a space formed by the spacer27between the plane of incidence124aand the obverse surface25a.

The first reflector28is arranged in an area different from the wavelength converter24on the obverse surface25aof the light transmissive member25. The second reflector29is arranged between the second support part211and the reverse surface25bof the light transmissive member25. The first reflector28and the second transmissive member29are each formed of a mirror such as a metal film or a dielectric multilayer film.

The first reflector28reflects the excitation light E emitted from each of the laser emitters22toward the second reflector29. The excitation light E reflected by the first reflector28is reflected by the second reflector29toward the wavelength converter24.

Then, there will be described when emitting the illumination light WL from the light source device200according to the present embodiment. The description will hereinafter be presented citing the behavior of the excitation light E emitted from the first laser emitter22aas an example.

The excitation light E emitted from the first laser emitter22aenters an inside of the light transmissive member25from the reverse surface25b, and enters the first reflector28disposed on the obverse surface25aof the light transmissive member25. The first reflector28reflects the excitation light beams E toward the second reflector29. The second reflector29reflects the excitation light E toward the wavelength converter124.

According to the light source device200related to the present embodiment, when making the excitation light E enter the obverse surface25aof the light transmissive member25at a small incident angle, it is possible to make the excitation light E enter the wavelength converter124by the first reflector28and the second reflector29reflecting and propagating the excitation light E even when arranging the incident position of the excitation light E and the wavelength converter124so as to be separated from each other. Therefore, the degree of freedom of an arrangement of the laser emitters22and the wavelength converter24increases.

Further, according to the light source device200related to the present embodiment, since the excitation light E enters the obverse surface25aof the light transmissive member25at a small incident angle, it is possible to prevent the reflection of the excitation light E by the obverse surface25aof the light transmissive member25. Therefore, by efficiently taking the excitation light E in the light transmissive member25and making the excitation light E enter the wavelength converter124, it is possible to efficiently take out the fluorescence YL as the illumination light WL.

Further, in the case of the present embodiment, the excitation light E is reflected twice until the excitation light E emitted from the laser emitter22enters the wavelength converter124. Here, the number of times of the reflection of the excitation light E until the excitation light enters the wavelength converter124becomes four or more, the light density of the excitation light E increases due to an influence of a variation in mounting the laser emitters22to thereby raise the temperature of the wavelength converter124, and there is a possibility that the deterioration of the fluorescence conversion efficiency and the breakage due to the heat occur. In contrast, in the case of the present embodiment, by setting the number of times of the reflection of the excitation light E to two, it is possible to minimize the influence of the variation in mounting the laser emitters22described above.

It should be noted that it is possible to scatter the excitation light E on the plane of incidence124ato thereby increase the efficiency of taking the excitation light E into the wavelength converter124by disposing the uneven structure26on the plane of incidence124aof the wavelength converter124instead of the spacer27in the light source device200according to the present embodiment. Further, it is possible to dispose both of the spacer27and the uneven structure26.

Third Embodiment

Then, a configuration of a light source device according to a third embodiment of the present disclosure will be described. It should be noted that in the present embodiment, constituents or members common to the second embodiment will be denoted by the same reference symbols, and the detailed description thereof will be omitted.

FIG.7is a diagram showing the configuration of the light source device according to the present embodiment.

As shown inFIG.7, the light source device201according to the present embodiment is provided with the base21, the plurality of laser emitters22, the wavelength converter124, the light transmissive member25, the spacer27, the first reflector28, the second reflector29, and an optical element30.

In the light source device201according to the present embodiment, the laser emitters22are arranged on the surface212aof the base part212of the base21so as to surround the periphery of the protruding part213. In other words, in the case of the present embodiment, the laser emitters22each emit the excitation light E along the surface212aof the base part212. In the present embodiment, the base part212of the base21constitutes the first support part210for supporting the plurality of laser emitters22.

The optical element30is opposed to the laser emitters22disposed at the light exit side of the laser emitters22, and folds the light paths of the excitation light E emitted from the laser emitters22toward the reverse surface25bof the light transmissive member25. The optical element30includes a plurality of triangular prisms30a. The triangular prisms30aare disposed so as to correspond respectively to the laser emitters22. The triangular prisms30aare disposed on the surface212aof the base part212so as to be opposed to the light exit side of the respective laser emitters22. Since the triangular prism30ais constituted by flat surfaces, it becomes easy to mount the triangular prism30aon the surface212aof the base part212.

The triangular prisms30aeach fold the light path of the excitation light E emitted from the corresponding laser emitter22toward the reverse surface25bof the light transmissive member25. The triangular prisms30aeach have a reflecting surface30alfor reflecting the excitation light E toward the first reflector28.

In the light source device201according to the present embodiment, the excitation light E emitted from each of the laser emitters22is reflected by the reflecting surface30alof the triangular prism30a, and then enters the light transmissive member25. The excitation light E enters the first reflector28disposed on the obverse surface25aof the light transmissive member25from the reverse surface25bof the light transmissive member25. The first reflector28reflects the excitation light E toward the second reflector29. The second reflector29reflects the excitation light E toward the wavelength converter124.

According to the light source device201related to the present embodiment, it is possible to bend the light path of the excitation light E emitted from each of the laser emitters22supported on the base part212of the base21using the triangular prism30ato make the excitation light E enter the light transmissive member25. Therefore, since the first support part210on which the laser emitters22are mounted is provided to the base part212of the base21, the heat of each of the laser emitters22is released to the base part212without passing the protruding part213. As described above, according to the light source device201related to the present embodiment, since the thermal resistance of the base21decreases, it is possible to enhance the cooling performance of the laser emitters22.

Further, since the base21releases the heat of the triangular prisms30a, it is possible to prevent the breakage of the triangular prisms30adue to the heat.

It should be noted that it is possible to scatter the excitation light E on the plane of incidence124ato thereby increase the efficiency of taking the excitation light E into the wavelength converter124by disposing the uneven structure26on the plane of incidence124aof the wavelength converter124instead of the spacer27in the light source device202according to the present embodiment. Further, it is possible to dispose both of the spacer27and the uneven structure26.

Fourth Embodiment

Then, a configuration of a light source device according to a fourth embodiment of the present disclosure will be described. It should be noted that in the present embodiment, constituents or members common to the second embodiment will be denoted by the same reference symbols, and the detailed description thereof will be omitted.

FIG.8is a diagram showing the configuration of the light source device according to the present embodiment.

As shown inFIG.8, the light source device202according to the present embodiment is provided with the base21, the plurality of laser emitters22, the wavelength converter124, the light transmissive member25, the spacer27, the first reflector28, the second reflector29, the optical element30, a side plate part31, and an optical layer19.

The light source device202according to the present embodiment has a package structure in which the plurality of laser emitters22is housed in the space S constituted by the base21, the side plate part31, and the light transmissive member25. It should be noted that it is desirable for the space S to be airtightly sealed.

The side plate part31surrounds the outer edge of the base21so as to form a frame-like shape to support the light transmissive member25. The side plate part31is disposed so as to protrude toward one surface of the base21. The side plate part31has an annular shape in the plan view. The side plate part31keeps a distance (clearance) between the base21and the light transmissive member25constant. Therefore, it is preferable for the side plate part31to have predetermined rigidity.

It is preferable for the side plate part31to be formed of a material having a linear expansion coefficient lower than the linear expansion coefficient of the base21and higher than the linear expansion coefficient of the light transmissive member25. As the material of the side plate part31, there is preferably used a metal material such as Kovar, or a ceramic material such as alumina, silicon carbide, or silicon nitride, and there is particularly preferably used Kovar or alumina.

The optical layer19is arranged between the plane of incidence124aof the wavelength converter124and the obverse surface25aof the light transmissive member25. In the case of the present embodiment, the optical layer19is disposed on the obverse surface25aof the light transmissive member25. Specifically, the optical layer19is disposed in an area opposed to the plane of incidence124aof the wavelength converter124out of the obverse surface25aof the light transmissive member25. The optical layer19is formed of a dichroic film which transmits the excitation light E and reflects the fluorescence YL.

According to the light source device202related to the present embodiment, since the optical layer19is disposed on the plane of incidence124aof the wavelength converter124, it is possible to prevent the deterioration of the efficiency of taking out the fluorescence YL caused by the fact that the fluorescence YL obtained by the wavelength conversion in the wavelength converter124is emitted from the plane of incidence124ato return toward the obverse surface25aof the light transmissive member25.

Further, since the light transmissive member25also functions as a sealing substrate for airtightly sealing the laser emitters22, additional members for sealing becomes unnecessary, and therefore, it is possible to reduce the manufacturing cost.

It should be noted that in the light source device202according to the present embodiment, the optical layer19can be disposed on the plane of incidence124aof the wavelength converter124.

Further, it is possible to scatter the excitation light E on the plane of incidence124ato thereby increase the efficiency of taking the excitation light E into the wavelength converter124by disposing the uneven structure26on the plane of incidence124aof the wavelength converter124instead of the spacer27in the light source device202according to the present embodiment. Further, it is possible to dispose both of the spacer27and the uneven structure26.

Further, in the light source device202according to the present embodiment, it is possible to make the excitation light E directly enter the wavelength converter as in the first embodiment without using the first reflector28and the second reflector29.

Fifth Embodiment

Then, a configuration of a light source device according to a fifth embodiment of the present disclosure will be described. It should be noted that in the present embodiment, constituents or members common to the second embodiment will be denoted by the same reference symbols, and the detailed description thereof will be omitted.

FIG.9is a diagram showing the configuration of the light source device according to the present embodiment.

As shown inFIG.9, the light source device203according to the present embodiment is provided with the base21, the plurality of laser emitters22, the wavelength converter124, the light transmissive member25, the spacer27, the first reflector28, the second reflector29, the optical element30, and a plurality of collimator lenses23.

In the light source device203according to the present embodiment, the plurality of collimator lenses23is disposed so as to correspond to the plurality of laser emitters22. The collimator lenses23are each arranged between the laser emitter22and the light transmissive member25, and each collimate the excitation light E emitted from the corresponding laser emitter22. The collimator lenses23are each supported by the first support part210via a lens holder123.

The collimator lenses23are each formed of, for example, a spherical lens. It should be noted that it is also possible for the collimator lens23to be formed of a diffraction-type lens. Since the diffraction-type lens is shaped like a plane, a burden of ensuring the mounting accuracy is reduced, and therefore, it is possible to obtain equivalent advantages as the spherical lens as described above.

In the present embodiment, the plurality of collimator lenses23includes a first collimator lens (a first optical system)23acorresponding to the first laser emitter22a, and a second collimator lens (a second optical system)23bcorresponding to the second laser emitter22b. In the present embodiment, the collimator lenses23are separated from each other, and are arranged at a distance from each other.

According to the light source device203related to the present embodiment, by arranging the collimator lenses23for substantially collimating the excitation light E between the respective laser emitters22and the light transmissive member25, it is possible to control the intensity distribution of the excitation light E entering the wavelength converter124. Thus, it is possible to suppress the light which fails to enter the wavelength converter124, and thus becomes the stray light, and the light which is reflected by the surface of the wavelength converter124, and thus becomes the stray light. Therefore, it is possible to efficiently use the excitation light E for the excitation of the fluorescence YL.

Further, it is possible to scatter the excitation light E on the plane of incidence124ato thereby increase the efficiency of taking the excitation light E into the wavelength converter124by disposing the uneven structure26on the plane of incidence124aof the wavelength converter124instead of the spacer27in the light source device203according to the present embodiment. Further, it is possible to dispose both of the spacer27and the uneven structure26.

Further, in the light source device203according to the present embodiment, it is possible to make the excitation light E directly enter the wavelength converter as in the first embodiment without using the first reflector28and the second reflector29.

There is cited when the collimator lenses23are formed separately from each other as an example in the light source device203according to the present embodiment, but it is possible to dispose an integrated optical system230corresponding to the laser emitters22as shown in FIG.10.

According to this configuration, since it becomes easy to adjust the positions of the laser emitters22and the optical system230, it is possible to prevent a decrease in light use efficiency of the excitation light E due to a mounting error of the laser emitters22.

It should be noted that although the description is presented illustrating the embodiments of the present disclosure, the present disclosure is not necessarily limited to the embodiments described above, but a variety of modifications can be added within the scope or the spirit of the present disclosure.

First Modified Example

For example, in the light source device200according to the second embodiment, it is possible to dispose a diffuser in a light path of the excitation light E from each of the laser emitters22to the plane of incidence24aof the wavelength converter24.

FIG.11Ais a diagram showing a configuration of an essential part of a light source device200A according to the present modified example.

As shown inFIG.11A, the light source device200A according to the present modified example is further provided with the diffuser40. The diffuser40is arranged in an area where the excitation light E enters on the reverse surface25bof the light transmissive member25. The diffuser40is formed of an uneven structure formed by performing, for example, a sandblast treatment on the reverse surface25b.

According to the light source device200A related to the present modified example, it is possible to scatter the excitation light E when passing through the diffuser40. Thus, since the homogeneity of the light intensity distribution of the excitation light E is enhanced, it is possible to prevent the decrease in fluorescence conversion efficiency and the breakage due to the heat generation in the wavelength converter124.

It should be noted that it is possible to form the diffuser40in the area where the excitation light E enters on the reverse surface25bby applying the present modified example to the light source device20according to the first embodiment.

Further, although the diffuser40is formed on the reverse surface25bof the light transmissive member25in the present modified example, it is possible to arrange a diffuser element as a separate member from the light transmissive member25between the reverse surface25band the laser emitter22.

Second Modified Example

FIG.11Bis a diagram showing a configuration of an essential part of a light source device200B according to the present modified example.

As shown inFIG.11B, the light source device200B according to the present modified example is further provided with a diffuser41. The diffuser41is formed on a reflecting surface of the second reflector29. The diffuser41is formed of an uneven structure formed by performing, for example, a sandblast treatment on the reverse surface25bof the light transmissive member25forming the reflecting surface of the second reflector29.

According to the light source device200B related to the present modified example, when reflecting the excitation light E with the second reflector29, it is possible to reflect the excitation light E in a scattered state due to the diffuser41. Thus, since the homogeneity of the light intensity distribution of the excitation light E is enhanced, it is possible to prevent the decrease in fluorescence conversion efficiency and the breakage due to the heat generation in the wavelength converter124.

Third Modified Example

FIG.11Cis a diagram showing a configuration of an essential part of a light source device200C according to the present modified example.

As shown inFIG.11C, the light source device200C according to the present modified example is further provided with a diffuser42. The diffuser42is formed on a reflecting surface of the first reflector28. The diffuser42is formed of an uneven structure formed by performing, for example, a sandblast treatment on the obverse surface25aof the light transmissive member25forming the reflecting surface of the first reflector28.

According to the light source device200C related to the present modified example, when reflecting the excitation light E with the first reflector28, it is possible to reflect the excitation light E in a scattered state due to the diffuser42. Thus, since the homogeneity of the light intensity distribution of the excitation light E is enhanced, it is possible to prevent the decrease in fluorescence conversion efficiency and the breakage due to the heat generation in the wavelength converter124.

Fourth Modified Example

FIG.11Dis a diagram showing a configuration of an essential part of a light source device200D according to the present modified example.

As shown inFIG.11D, the light source device200D according to the present modified example is further provided with a diffuser43. The diffuser43is arranged between the plane of incidence124aof the wavelength converter124and the obverse surface25aof the light transmissive member25. Specifically, the diffuser43is formed in an area opposed to the plane of incidence124aof the wavelength converter124out of the obverse surface25aof the light transmissive member25. The diffuser43is formed of an uneven structure formed by performing, for example, a sandblast treatment on the obverse surface25a.

According to the light source device200D related to the present modified example, it is possible to scatter the excitation light E when passing through the diffuser43. Thus, since it is possible to make the excitation light E enhanced in homogeneity of the light intensity distribution enter the plane of incidence124aof the wavelength converter124, it is possible to prevent the decrease in fluorescence conversion efficiency and the breakage due to the heat generation in the wavelength converter124.

It should be noted that it is possible for the light source device to adopt a structure obtained by combining two or more of the diffusers40,41,42, and43in the first modified example through the fourth modified example.

Further, in the light source devices according to the embodiments and modified examples described above, there is cited when emitting the illumination light WL having a white color including the excitation light E and the fluorescence YL as an example, it is possible to arrange that yellow light including only the fluorescence YL is taken out as the illumination light by adjusting the thickness of the wavelength converter24,124and the light intensity of the excitation light E. In this case, by forming a dichroic film for reflecting the excitation light E and transmitting the fluorescence YL on the exit surface of the wavelength converter24,124, it is possible to efficiently take out only the fluorescence YL as the illumination light.

Further, in the light source devices according to the embodiments and the modified examples described above, there is cited when the plurality of laser emitters22is provided as an example, the number of the laser emitters22is not a limitation, and it is possible to adopt a configuration including only the first laser emitter22a.

Further, although in the embodiments described above, there is illustrated the projector1provided with the three light modulation devices4R,4G, and4B, the present disclosure can also be applied to a projector for displaying a color picture with a single light modulation device. Further, the light modulation device is not limited to the liquid crystal panel described above, but a digital mirror device, for example, can also be used.

Further, although in the embodiments described above, there is described the example of applying the light source device according to the present disclosure to the projector, this is not a limitation. The light source device according to the present disclosure can also be applied to lighting equipment such as a headlight for a vehicle.

A light source device according to an aspect of the present disclosure may have the following configuration.

The light source device according to an aspect of the present disclosure includes a first laser emitter configured to emit first light in a first wavelength band, a light transmissive member which has a first surface and a second surface opposite to the first surface, and the second surface which the first light emitted from the first laser emitter enters, a base having a first support part configured to support the first laser emitter, and a second support part configured to support the light transmissive member, and a wavelength converter which is arranged on the first surface of the light transmissive member, and which is configured to convert the first light into second light in a second wavelength band different from the first wavelength band, wherein the wavelength converter has a plane of incidence including an incident area where the first light enters, and an exit surface which is disposed at an opposite side to the plane of incidence, and which is configured to emit the second light, and the second support part supports an area corresponding to the incident area out of the second surface of the light transmissive member.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration in which an air layer is disposed between the plane of incidence of the wavelength converter and the first surface of the light transmissive member.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration in which one of the plane of incidence of the wavelength converter and an area opposed to the plane of incidence in the first surface of the light transmissive member is provided with an uneven structure, and the air layer is provided to the uneven structure.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration further including a spacer arranged between the plane of incidence of the wavelength converter and the first surface of the light transmissive member, wherein the air layer is disposed in a space formed by the spacer between the plane of incidence and the first surface.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration further including an optical element which is opposed to the first laser emitter disposed at a light exit side of the first laser emitter, and which is configured to fold a light path of the first light emitted from the first laser emitter toward the second surface of the light transmissive member.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration further including a first reflector arranged in an area different from the wavelength converter on the first surface, and a second reflector arranged between the second support part and the second surface of the light transmissive member, wherein the first reflector reflects the first light emitted from the first laser emitter toward the second reflector, and the second reflector reflects the first light reflected by the first reflector, toward the wavelength converter.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration further including a diffuser configured to diffuse the first light, wherein the diffuser is formed on at least one of a reflecting surface of the first reflector and a reflecting surface of the second reflector.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration further including a diffuser configured to diffuse the first light, wherein the diffuser is arranged in a light path of the first light from the first laser emitter to the plane of incidence of the wavelength converter.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration in which the diffuser is arranged in an area where the first light emitted from the first laser emitter enters on the second surface of the light transmissive member.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration in which the diffuser is arranged between the plane of incidence of the wavelength converter and the first surface of the light transmissive member.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration further including an optical layer which is arranged between the plane of incidence of the wavelength converter and the first surface of the light transmissive member, and which is configured to transmit the first light and reflect the second light.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration further including a first optical system which is arranged between the first laser emitter and the light transmissive member, and which is configured to collimate the first light emitted from the first laser emitter.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration further including a second laser emitter configured to emit the first light, and a second optical system configured to collimate the first light emitted from the second laser emitter, wherein the first optical system and the second optical system are separated from each other, and are arranged at a distance from each other.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration further including a second laser emitter configured to emit the first light, and a second optical system configured to collimate the first light emitted from the second laser emitter, wherein the first optical system and the second optical system are integrally formed.

In the light source device according to the aspect of the present disclosure, there may be adopted a configuration in which the second support part has a support surface configured to support the second surface of the light transmissive member, and the support surface is larger in area than the incident area of the wavelength converter.

A projector according to an aspect of the present disclosure may have the following configuration.

The projector according to the aspect of the present disclosure includes the light source device according to one of the above aspects of the present disclosure, a light modulation device configured to modulate the light from the light source device, and a projection optical device configured to project the light modulated by the light modulation device.