JP7228010B2 - solid state light source - Google Patents

Description

The present invention relates to a solid-state light source device that obtains luminescent color by exciting phosphors with a blue laser light source.

With the remarkable development of solid-state light-emitting devices such as LEDs in recent years, lighting devices that use such solid-state light-emitting devices as light sources have become small, lightweight, low-power, environmentally friendly, and long-life light sources. It has been widely used in various lighting fixtures, and has been used as a headlight device for vehicles with excellent visibility that can be controlled in various ways as an in-vehicle electronic device, and as a light source for projection display devices. there is

For example, conventionally, a headlight device for a vehicle includes a low beam LED light source array, a high beam LED light source array, and a first optical light guide that receives and collimates the low beam light and the high beam light from these LED light sources. A vehicle headlamp that includes a second optical light guide or the like that diffuses low beam light and high beam light as a combination of diffusion patterns, and that mechanically supports these arrays and optical light guides in a casing is disclosed in the following patent documents. 1.

As a new light source device, Patent Document 2 discloses a highly efficient and compact solid-state light source device that uses a laser light source as a light source. Specifically, a configuration is disclosed in which white light is efficiently obtained by exciting green, red, or yellow phosphors with blue laser light in combination with blue laser light, which is excitation light.

Japanese Patent Publication No. 2008-532250 JP 2015-121606 A

As the luminous efficiency of LEDs, which are solid-state light sources, has improved, it has become effective to use them as luminous sources in vehicle headlamp devices. However, the above-described prior art, Patent Document 1, does not disclose specific technical means for improving the light utilization efficiency.

On the other hand, as a light source for a projector, as shown in Patent Document 2, a system has been proposed in which the étendille is reduced by exciting a phosphor with a blue laser beam to increase the light utilization efficiency of the illumination system. No specific technical means for improving the luminous efficiency of the phosphor is disclosed.

Therefore, the present invention provides a light source device that can be easily used as a modularized planar light source for illumination, and has a high utilization efficiency of excitation light from an LED light source, particularly a blue LED, and light emitted from the excitation light. The object of the present invention is to provide a headlight device for a vehicle and a light source for a blue laser projector.

As a first embodiment for achieving the above object, according to the present invention, there is provided a solid-state light-emitting portion that generates excitation light, and a light-collecting portion that collects the excitation light from the solid-state light-emitting portion into a point. and a reflection/scattering/fluorescence emission unit that alternately repeats reflection/scattering of the excitation light and emission of fluorescent light excited by the excitation light in the vicinity of the focal point of the excitation light collected into a point by the light collecting unit. , wherein the solid-state light emitting unit includes a phosphor layer coated with a phosphor, and an excitation light source that excites the phosphor, and the excitation light from the excitation light source is light of a specific polarized wave. It is configured to illuminate the phosphor layer at an angle of incidence in the range of 40 degrees to 70 degrees with respect to the phosphor layer.

According to the above-described present invention, it is possible to realize a light source device that has a high luminous efficiency of a light source that excites a phosphor using blue light as excitation light, that can be manufactured at low cost, that is small and that can be easily modularized, and that consumes low power. Therefore, it is possible to realize a headlight device for a vehicle and a light source device for a projector which are excellent in environmental protection and have a long life.

1A and 1B are a perspective view of a light source unit and an overall configuration (a) in which a vehicle headlight device as Embodiment 1 of the light source device of the present invention is applied as a headlight of an automobile. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing (b) which shows the whole structure (a) of the headlight apparatus for vehicles as Example 1 of the light source device of this invention, and its light source part. FIG. 6 is a diagram showing the overall configuration of a projector as a second embodiment of the light source device of the present invention; It is a first embodiment of the light source section of the illumination optical system of the projector. It is a second embodiment of the light source section of the illumination optical system of the projector. FIG. 10 is a diagram showing a modification in which a total reflection lens is used as a reflector in the first implementation of the light source section of the illumination optical system of the projector; FIG. 4 is a detailed cross-sectional view showing the principle of the light source unit according to the present invention, showing an example of an excitation light reflection type in which excitation light is incident in the same direction as the emission direction of fluorescent light. FIG. 4 is a detailed cross-sectional view showing the principle of the light source unit according to the present invention, showing an example of an excitation light transmission type in which excitation light is incident from a direction different from the emission direction of fluorescent light. FIG. 4 is a detailed cross-sectional view showing a light source section according to the present invention, showing an example of an excitation light reflection type in which excitation light is incident in the same direction as the emission direction of fluorescent light. FIG. 4 is a detailed cross-sectional view showing a light source section according to the present invention, showing an example of an excitation light transmission type in which excitation light is incident from a direction different from the emission direction of fluorescent light. It is a detailed cross-sectional view showing the principle of the light source unit according to the present invention, showing an example of an excitation light reflection type in which excitation light is incident in the same direction as the emission direction of fluorescent light according to the prior art. FIG. 10 is a detailed cross-sectional view showing the principle of the light source unit according to the present invention, showing an example of an excitation light transmission type in which excitation light according to the prior art is incident from a direction different from the emission direction of fluorescent light. It is a figure which shows the relationship between the incident angle of the excitation light to fluorescent substance, and a reflection angle. FIG. 4 is a diagram showing an example of angular characteristics of reflectance for a substance with a refractive index of 1.5 for P-polarized light and S-polarized light. FIG. 4 is a characteristic diagram showing excitation light incident angle characteristics of conversion efficiency of green fluorescent light to blue excitation light. FIG. 4 is a characteristic diagram showing the incident angle dependence of excitation light on a phosphor layer for each polarized light. FIG. 4 is a characteristic diagram showing the angular dependence of excitation light on the output of fluorescent light; FIG. 3 is a characteristic diagram showing excitation light incident angle dependence on a phosphor that is an example of the present invention. It is a figure which shows the light conversion efficiency with respect to the incident angle for each excitation light polarization direction to a fluorescent substance layer. FIG. 4 is a diagram showing the ratio of light conversion efficiency depending on the polarization direction with respect to the angle of incidence of excitation light on the phosphor layer.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited to the following description, and various changes and modifications can be made by those skilled in the art within the scope of the technical ideas disclosed in this specification. In addition, in the drawings for explaining the present invention, parts having the same function are denoted by the same reference numerals, and repeated description thereof may be omitted.

First, FIG. 1 shows a perspective view and a partially enlarged view of a vehicle 1 equipped with a vehicle headlight device using solid-state light-emitting devices according to an embodiment of the present invention. FIG. 1(a) shows the entire vehicle 1 equipped with a vehicle headlight device 1000 of the present invention, and FIG. 1(b) shows an enlarged view of the headlight device portion of the vehicle. .

FIG. 2(a) is a cross-sectional side view of the headlight device 1000 shown in FIG. 1(b), and FIG. 2(b) shows a structural cross-section of the light source portion thereof. In addition, FIG. 3 shows a display in which the light source device according to the embodiment of the present invention is used as a light source, that is, information including the traveling direction of the vehicle is displayed in front of the vehicle by using the light source device of the above headlight device. It is a figure which shows the whole projector structure for vehicles which projects and displays.

(Example 1)
As shown in these figures, the headlight device 1000 shown in FIG. 1 is basically composed of a visible light lighting unit 10 as a light source device, and a space in front of the vehicle 1, which emits illumination light from the lighting unit. and an optical system for irradiating the road surface on which the vehicle 1 is running, which is a so-called projector lens 51 . Furthermore, instead of the projector lens 51, a reflection mirror 60 may be used to form the projection optics. Alternatively, as shown in FIG. By doing so, the distribution of the irradiation light on the road surface can be controlled with high accuracy, and the volume of the entire headlight device can be reduced.

As is clear from these figures, in the headlight device 1000 according to the present invention, the illumination light from the visible light illumination unit 10 is converted into fluorescent light by irradiating the phosphor with the excitation light from the excitation light source 12. It is configured to obtain In the light source device, as an example, when white light is obtained, as shown in FIG. white light can be obtained by mixing with the blue excitation light. That is, it is preferable to emit a light beam in a wavelength range that is complementary to the excitation light with respect to white. The obtained irradiation light flux is bent in a predetermined direction by the reflecting mirror 60 as shown in FIG. 2(a). As a result, more precise control of irradiation direction and intensity becomes possible due to the degree of freedom in the shape of the reflecting surface.

Next, details of each component of the headlight device 1000 according to the present invention described above will be described below.

<Light source unit>
In order to obtain white light, the visible light illumination unit 10, which is the light source device of the present invention, uses one or more semiconductor light source elements LED (Light Emitting Diode) or LASER (which are solid-state light sources to be described later) as the excitation light source 12 to obtain white light. Light Amplification by Stimulated Emission of Radiation) is used to mix the light obtained by exciting the phosphor 19 emitting yellow or green and red light with the excitation light to obtain desired white light. As shown in FIG. 2(b), a method (hereinafter referred to as a “reflection method”) in which the fluorescent light and the excitation light are emitted from the direction in which the mixed color light is emitted and the fluorescent light and the excitation light are reflected by the reflecting surface 17 and emitted in a desired direction. , There is a method of arranging the excitation light source on the bottom surface of the groove in which the phosphor 19 is arranged (not shown, hereinafter referred to as "transmission method"), but the transmission method is adopted in order to make the whole headlight device compact. often.

In the following, focusing on the reflection system shown in FIG. 2(b), and for convenience of explanation, the configuration and the effects obtained will be described for the system in which blue laser light is used as the excitation light.

The inventors have found through experiments that it is effective to reduce the following three factors in order to efficiently obtain the light source light from the light source unit.
(1) The excitation light 13 from the excitation light source 12 is efficiently applied to the phosphor.
(2) Efficiently emit the fluorescence generated by the phosphor 19 in a desired direction.
(3) Increase the luminous efficiency of the phosphor.

In order to realize the above (1), the phosphor layer containing the phosphor 19 is irradiated with the excitation light flux 13 . At this time, an antireflection film 21 is provided on the surface to reduce reflection on the surface of the phosphor layer. Furthermore, for the excitation light 13, the output of fluorescent light was determined by experiment with respect to the same input energy of excitation light as in FIG. 13 showing the relationship between the angle of incidence on the phosphor layer and the angle of reflection. As a result, as shown in FIG. 19, it was found that the light conversion efficiency (output light energy/incident light energy) is higher when using P-polarized light than when using S-polarized light, and light can be extracted. FIG. 20 shows the ratio of the efficiency when P-polarized light is used and the light conversion efficiency when S-polarized light is used, using the incident angle of excitation light as a parameter. It was found that P-polarized light has a higher efficiency, and that the efficiency is highest when the incident angle is around 30 degrees. This was caused by both the difference in reflectance at the interface due to the difference between the P wave and the S wave shown in FIG. 14 and the improvement in luminous efficiency due to cooling of the phosphor, which will be described in detail below.

Further, the inventors changed the structure of the phosphor layer to the conventional structure in which a gap exists between the phosphor 19 and the binder 23 shown in FIGS. 11 and 12, as shown in FIGS. In order to greatly reduce the density of the voids, the phosphor 19 and the binder 23 are baked to form a structure that prevents reflection at the interface between the phosphor and the vacuum (or air). LuAG:Ce (refractive index: 1.85) was used as the green phosphor, and YAG:Ce (refractive index: 1.82) was used as the yellow phosphor. A comparison was made using aluminum oxide (alumina) (refractive index 1.76) and titanium oxide (refractive index 2.5), which have high transparency and thermal conductivity. As a result, when aluminum oxide having a small refractive index difference between the phosphor 19 and the binder 23 is used as the binder 23, the generation of the scattered light 21 inside the phosphor is reduced. As a result, the light output was improved by 6% or more. That is, it was found that it is preferable to use a member having a refractive index difference of 0.2 or less from the phosphor as the binder.

Next, in order to realize the above-mentioned (2), groove portions 16 are provided in structures 15 and 18 provided with phosphor layers as shown in FIGS. In the cross-sectional direction of , it has a cross-sectional shape (so-called “mortar shape”) in which a part or the whole becomes smaller in the depth direction. At this time, by providing reflective films 17 and 20 having a visible light reflectance of 90% or more on the contact surfaces of the structure 18 and the phosphor 19, the obtained light can be emitted in a desired direction. Also, when the phosphor 19 and the binder are fired in the structure 18, shrinkage occurs during cooling. As a result, an air or vacuum interface is generated between the reflective surface and the phosphor layer. Since the light is emitted, the light can be efficiently extracted to the subsequent optical system.

Finally, regarding the technical means for realizing the above-mentioned (3), the inventors investigated the relationship between the phosphor temperature and the photoconversion efficiency in the state of being irradiated with the excitation light, and found that the photoconversion due to the temperature rise of the phosphor. I've found that it's less efficient. Therefore, in order to reduce the temperature of the phosphor, the above structure is made of metal with high thermal conductivity, and the reflective surface of the groove portion is made of aluminum or silver alloy, which has high reflectance even with a metallic reflective film. By providing the film, the light conversion efficiency was improved by 8% or more. At this time, the phosphor 19 and the binder 23 made of aluminum oxide are baked and thermally bonded to reduce the temperature rise of the phosphor caused by the excitation light, thereby achieving high efficiency.

In addition, as another means for reducing the temperature rise, by obliquely irradiating the phosphor layer with the excitation light, the energy density of the excitation light incident on the phosphor layer is reduced, and the heat conduction efficiency after heat reception is improved. It has been found that the light output of excitation light and fluorescence light can be improved. The results are shown in FIG. The horizontal axis represents the angle of incidence of the excitation light on the phosphor layer, and the vertical axis represents the outputs of the excitation light and the fluorescence light. In FIG. 18, the horizontal axis represents the angle of incidence of the excitation light on the phosphor layer, and the vertical axis represents the output when the excitation light is perpendicularly incident on the phosphor layer, relative to the excitation light when the relative value is 1.00. As described above, the energy density of the excitation light incident on the phosphor layer is reduced by irradiating the phosphor layer with the excitation light obliquely. The light output of the excitation light and the fluorescence light was improved by increasing the heat conduction efficiency afterward. From the above results, it is particularly preferable that the excitation light beam is P-polarized light and that the incident angle is in the range of 40 degrees to 70 degrees.

As described above, the visible light illumination unit 10 as the light source device of the present invention uses, as the excitation light source 12, one or more semiconductor light source elements LED (Light Emitting Diode) or LASER, which are solid light sources to be described later, to obtain white light. (Light Amplification by Stimulated Emission of Radiation), the light obtained by exciting the phosphor 19 emitting yellow or green and red light and the excitation light are mixed to obtain desired white light. Further, as shown in FIG. 2B, in the embodiment, the fluorescent light and the excitation light are reflected by the reflecting surfaces 17 and 20 and emitted in the desired direction by irradiating from the emitting direction of the mixed color. The method (hereinafter referred to as “reflection method”) has been described. However, the present invention is not limited to them, and as shown in FIGS. Reflection loss is reduced by providing an antireflection film also on the light exit surface from which part of the fluorescent light and the excitation light are mixed and emitted. Needless to say, these examples have no other structural differences, and similar effects can be obtained with similar structures.

(Example 2)
<Projector>
A vehicle projector employing a light source unit as another embodiment of the present invention as a light source will be described below with reference to FIG. This figure shows the overall structure of the projector, and in particular, the method of modulating the light intensity according to the video signal by a so-called transmissive liquid crystal panel will be described. In the same figure, in order to distinguish the elements arranged on the optical paths of the respective colored lights, the symbols R, G, and B indicating the colored lights are added after the reference numerals, and the suffixes for the colored lights are omitted when there is no need to distinguish them. In addition, in order to clarify the polarization directions, a right-handed orthogonal coordinate system will be used in the following description. That is, the Z axis is the optical axis 101, the Y axis is the axis parallel to the paper surface of FIG. A direction parallel to the Y direction and the X axis is referred to as the X direction. Further, in order to distinguish between the polarization directions, X-polarized light will be referred to as X-polarized light, and Y-polarized light will be referred to as Y-polarized light.

3, the optical system of the projector includes an illumination optical system 100, a light separating optical system 30, a relay optical system 40, three field lenses 29 (29R, 29G, 29B), and three transmissive liquid crystal panels 60 (60R, 60G, 60B), a light combining prism 200 as light combining means, and a projection lens 300 as projection means. The liquid crystal panel 60 has an incident side polarizing plate 50 (50R, 50G, 50B) on the light incident side and an output side polarizing plate 80 (80R, 80G, 80B) on the light emitting side. These optical elements are mounted on a substrate 550 to form the optical unit 500 . The optical unit 500 is mounted in a housing (not shown) together with a drive circuit 570 that drives the liquid crystal panel 60, a cooling fan 580 that cools the liquid crystal panel 60 and the like, and a power supply circuit 560 that supplies power to each circuit. Configure.

The details of each part constituting the projector described above will be described below. An illumination optical system 100 for uniformly illuminating the liquid crystal panel 60, which is an image display element, comprises a visible light illumination unit 10 composed of solid state light emitting elements that emit substantially white light as described above, and first and second lenses that constitute an optical integrator. It includes arrays 21 and 22 , a polarization conversion element 25 and a condensing lens (superimposition lens) 27 .

A photo-decomposing optical system 30 for photo-decomposing the substantially white light from the illumination optical system 100 into three primary color lights includes two dichroic mirrors 31 and 32 and a reflecting mirror 33 for changing the direction of the optical path. The relay optical system 40 includes a first relay lens 41 that is a field lens, a second relay lens 42 that is a relay lens, and optical path folding mirrors 45 and 46 .

In such a configuration, a light beam substantially parallel to an optical axis 101 indicated by a dashed line in FIG. The light emitted from the light source unit 10 enters the polarization conversion integrator. This polarization conversion integrator consists of an optical integrator that realizes uniform illumination consisting of a first array lens 21 and a second array lens 22, and a polarized light for aligning the polarization direction of light to a predetermined polarization direction and converting it into linearly polarized light. and a polarization conversion element 25 consisting of a beam splitter array. That is, in the polarization conversion integrator described above, the light from the second array lens 22 is aligned by the polarization conversion element 25 into a predetermined polarization direction, for example, X-polarized light of linearly polarized light.

Projected images of the lens cells of the first array lens 21 are superimposed on the respective liquid crystal panels 60 by the condenser lens 27, the field lenses 29G and 29B, the relay optical system 40 and the field lens 29R. In this manner, the liquid crystal panel is uniformly illuminated while aligning the light from the solid-state light source with random polarization directions into a predetermined polarization direction (here, X-polarized light).

On the other hand, the light separating optical system 30 separates the substantially white light emitted from the illumination optical system 100 into B light (light in the blue band), G light (light in the green band), and R light (light in the red band). Then, the light is guided to respective optical paths (B optical path, G optical path, R optical path) toward the corresponding liquid crystal panels 60 (60R, 60G, 60B). That is, the B light reflected by the dichroic mirror 31 is reflected by the reflecting mirror 33, passes through the field lens 29B and the incident side polarizing plate 50B, and enters the liquid crystal panel 60B for B light (B optical path). Also, the G light and the R light pass through the dichroic mirror 31 and are separated into the G light and the R light by the dichroic mirror 32 . The G light is reflected by the dichroic mirror 32 and enters the liquid crystal panel 60G for G light through the field lens 29G and the incident side polarizing plate 50G (G optical path). The R light passes through the micromirror 32 and enters the relay optical system 40 . The R light incident on the relay optical system 40 is condensed (converged) in the vicinity of the second relay lens 42 via the reflecting mirror 45 by the first relay lens 41 of the field lens, and diverges toward the field lens 29R. . Then, the light is made substantially parallel to the optical axis by the field lens 29R, passes through the incident side polarizing plate 50R, and enters the liquid crystal panel 60R for R light (R optical path).

Each liquid crystal panel 60 (60R, 60G, 60B) constituting the light intensity modulation section is driven by a drive circuit 570, and the degree of polarization is increased by the incident side polarizing plate 50 (50R, 50G, 50B) having a transmission axis in the X direction. , modulates the X-polarized color light incident from the light separating optical system 30 in accordance with the color image to form a Y-polarized optical image.

The Y-polarized optical image of each color light formed as described above enters the output polarizing plate 80 (80R, 80G, 80B). The incident-side polarizing plates 80R, 80G, and 80B are polarizing plates having a transmission axis in the Y direction, thereby removing unnecessary polarized light components (here, X-polarized light) and improving the contrast. The optical images of each color light formed by the above-described method are incident on the combining prism 200, which is light combining means, and combined to obtain a color image, which is enlarged and projected by the projection lens 300, for example, onto the road surface.

<Light source unit for projector>
FIG. 4 is a diagram for explaining another configuration of the solid-state light source device that is one of the embodiments of the present invention, particularly the principle of the light source unit 10 of the vehicle projector. The unit 10 includes a semiconductor laser element group 110 in which a plurality of semiconductor laser elements or light emitting diodes that emit light in the blue band (B color), which are solid-state light emitting sources, are arranged on a substantially disk-shaped substrate; A reflecting mirror (reflector) 130 having, for example, a parabolic surface, which is inclined at an angle of approximately 45 degrees facing the laser light emitting surface of the element group 110, and rotates in the vicinity of the focal point (F) of the reflecting mirror. A disc (wheel) member 140 that rotates and drives the member to rotate at a desired rotational speed, such as an electric motor 150 .

A light source unit as a second embodiment of the present invention will be described with reference to FIG. A first reflecting mirror (reflector) 130 is configured to have a smaller diameter than a second reflecting mirror (reflector) 130', and white light can be obtained from the first reflecting mirror (reflector) 130. FIG. The excitation light from the semiconductor laser element group 110 is incident on the outer peripheral portion of the disc (wheel) member 140 . A spherical reflector 149 is provided for reflecting the fluorescent light emitted from the vicinity of the focal point F that does not reach the reflecting surface 131 of the reflector 130 . With such a spherical reflector 149, almost all of the fluorescent light emitted from the vicinity of the focal point F can be output through the reflector 130, so that the light utilization efficiency can be improved. 9 and 10 is provided on the emission side surface (upper surface) of the substrate 142', the emission direction of the emitted light from the phosphor 19 can be controlled. , the energy conversion efficiency is improved by increasing the light capture rate of the subsequent illumination optical system (not shown).

In the above description, the fluorescent surface formed on the base material and the reflection diffusion surface or the transmission diffusion surface are sequentially switched over time with respect to the excitation light condensed near the focal point F from the reflector. By dividing the surface of the disk-shaped base material into a plurality of segments and rotating it, it is possible to improve the heat dissipation effect and reduce the damage to the phosphor. However, the present invention is not limited to this. Alternatively, by adopting a structure in which the relative position with respect to the focal point F can be changed, excitation light is condensed at one point on the phosphor, thereby reducing damage to the phosphor.

FIG. 6 shows a configuration using a so-called total reflection lens 135 as a reflecting mirror (reflector), in which a total reflection surface and a condensing lens are made up of one member. According to such a configuration, the excitation light (blue laser beam) near the optical axis passes through the condensing lens 136, while the excitation light (blue laser beam) at a position away from the optical axis is totally reflected by the total reflection portion 137. All the rays are reflected and condensed to a point on the disk (wheel) member 140, and then the blue light is reflected and diffused as it is, or the yellow light is converted and diffused. Then, of the blue light and yellow light diffused from one point of the disk (wheel) member 140, the rays near the optical axis pass through the condenser lens 136 again, and both rays become rays parallel to the optical axis. Further, it is reflected by the separation mirror 120 and enters the illumination optical system 100 of the projector. A reflecting film may be formed on the surface of the total reflection portion 137, and the surface shape of the reflector may be a curved surface such as a paraboloid or an ellipsoid, similar to the reflector. (surface) is desirable. That is, with such a configuration, similarly to the above, white illumination light can be obtained, and the influence of focus movement (axial chromatic aberration) due to color can be suppressed to a practically negligible level.

The color separation mirror 120 shown in FIG. 6 is provided with a polarization separation film that transmits P-polarized light and reflects S-polarized light on the excitation (blue laser) light source side of the base material 121, and the reflection on the opposite side. A dichroic coat that transmits blue light and reflects yellow light is deposited on the mirror (reflector) side. The P-polarized blue laser light enters the separation mirror, passes through the polarization separation coated surface, dichroic coated surface, and enters the reflecting mirror (reflector). Excitation light (blue laser light) incident on the reflector is condensed at one point on the disk (wheel) member, part of the blue light excites the phosphor and emits yellow light, and part of the blue light The light has its polarization rotated by 90 degrees and is diffused into S-polarized light. After that, the yellow light and the blue light, which have been collimated by a reflector and aligned with the yellow light and the S-polarized light, enter the separation mirror 120 again.

On the other hand, the S-polarized blue light passes through the dichroic coat surface, is reflected by the polarization separation coat surface, and enters the illumination system of the projector.

The light source unit described above is not limited to the light source unit for the vehicle projector described above, and can also be employed as the visible light illumination unit 10 that is the light source device of the headlight device 1000 described above. . According to this, similarly to the light source unit described above, light obtained by exciting the phosphor 19 emitting yellow or green and red light using a semiconductor light source element LED or LASER is mixed with the excitation light. Therefore, it is possible to obtain a solid-state light source device that can obtain desired white light and is excellent in light emission intensity and heat dissipation effect. In addition, the light source unit is not limited to a vehicle projector, and can be used as a light source for general projectors that project and display various images on a surface such as a screen. It will be clear to those skilled in the art.

The light sources and light source devices according to various embodiments of the present invention have been described above. However, the present invention is not limited only to the above-described embodiments, and is a specific technical means for improving the luminous efficiency of phosphors and improving the utilization efficiency in an illumination optical system. It is also possible to add the configuration of other embodiments to the configuration of . Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

Reference Signs List 1 vehicle 1000 headlight device 10 visible light illumination unit 12 excitation light source 13 excitation light (blue light flux) 17 reflective surface 15, 18 structure 17, 20 reflective film, DESCRIPTION OF SYMBOLS 19... Phosphor, 23... Binder, 21, 22... Lens array, 25... Polarization conversion element, 27... Condensing lens, 29... Field lens, 30... Light separation optical system, 31, 32... Dichroic mirror, 33... Reflection Mirror 40 Relay lens optical system 50 Incidence side polarizing plate 60 Liquid crystal panel 80 Output side polarizing plate 100 Illumination optical system 200 Light combining prism 300 Projection lens 500 Optical unit 550 Base 560 Power supply circuit 570 Drive circuit 580 LED collimator unit outside cooling fan 51 Projector lens 60 Reflecting mirror

Claims (5)

a solid-state light emitting unit that generates excitation light and fluorescent light excited by the excitation light ;
a condensing unit that collects the excitation light and the fluorescent light from the solid-state light emitting unit into a point ,
The solid-state light emitting unit includes a phosphor layer coated with a phosphor and a semiconductor laser element that excites the phosphor,
The phosphor layer is formed by firing the phosphor and a binder, and the binder is a member having a refractive index difference of 0.2 or less from the phosphor,
A solid-state light source device , wherein the excitation light from the semiconductor laser element is configured to irradiate the phosphor layer with an incident angle of 40 degrees to 70 degrees with respect to the phosphor layer. The solid-state light source device according to claim 1,
The solid-state light source device, wherein the solid-state light emitting unit is configured by arranging a plurality of semiconductor laser elements in a plane. In the solid-state light source device according to claim 1,
The solid-state light source device, wherein the phosphor emits a light beam in a wavelength range that is complementary to the excitation light with respect to white. In the solid-state light source device according to claim 3,
The solid-state light source device, wherein the excitation light from the solid-state light emitting unit is blue light. The solid-state light source device according to claim 1 ,
A solid-state light source device using P-polarized light as the excitation light.

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