JPWO2018198201A1 - Solid-state light source device and headlight device - Google Patents

Abstract

High light conversion efficiency is obtained in a light source device that excites a phosphor with excitation light to obtain desired light. Light source device In order to efficiently irradiate the excitation light from the excitation light source to the phosphor in order to efficiently obtain the light source light, an antireflection film is provided on the surface of the phosphor layer to reduce the reflection in the phosphor layer by using the excitation light as P-polarized light. By increasing the light receiving area, the cooling efficiency is improved and the light conversion efficiency is improved. Furthermore, in order to greatly reduce the density of voids between the phosphor and the binder constituting the phosphor layer, the phosphor and the binder are fired to prevent reflection at the phosphor-vacuum (or air) interface. I do. In addition, the structure provided with the phosphor layer is provided with a groove portion, and the opening shape of the groove portion has a cross-sectional shape in which a part or the whole decreases in a depth direction in a cross-sectional direction in the drawing. By providing a reflection film having a visible light reflectance of 90% or more on the surface, light captured in a desired direction can be emitted, so that the light use efficiency of the illumination optical system can be increased.

Description

  The present invention relates to a light source device that obtains a luminescent color by exciting a phosphor with a blue laser light source, and a headlight device using the same.

  With the remarkable development of solid-state light-emitting elements such as LEDs in recent years, lighting devices that use the solid-state light-emitting elements as light sources are small, lightweight, low power consumption, and long-life light sources with excellent environmental protection. It has been widely used in various types of lighting equipment, and has been used as a vehicle headlight device with excellent visibility that can be controlled in various ways as an in-vehicle electronic device, and also as a light source of a projection display device. I have.

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

  Further, according to Patent Document 2, as a new light source device, a highly efficient and small solid-state light source device using a laser light source as a light source is disclosed. Specifically, a configuration is disclosed in which a green laser, a red phosphor, or a yellow phosphor is excited by blue laser light to efficiently obtain white light in combination with blue laser light, which is excitation light.

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

  An LED, which is a solid light source, has been effectively used as a light source in a headlamp device for a vehicle as its luminous efficiency has been improved. However, the above-mentioned prior art and Patent Document 1 do not disclose specific technical means for improving the light use efficiency.

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

  Thus, the present invention provides a light source device that can be easily used as a modular planar light source for illumination, in which an LED light source, in particular, a vehicle having high utilization efficiency of excitation light from a blue LED and light emitted from the excitation light. It is an object of the present invention to provide a headlight device for a camera and a light source for a blue laser projector.

  According to the present invention, as a first embodiment for achieving the above object, there is provided a vehicle headlight device that is attached to a part of a vehicle and irradiates illumination light on a road surface on which the vehicle runs. As a light source device for generating the illumination light, a blue LED is used as an excitation light source to excite a phosphor to obtain white light.

  Further, as a projector light source according to the second embodiment, blue laser light is focused on a phosphor to excite the phosphor to reduce the light emission point, reduce etendue, and increase the efficiency of the illumination optical system. At this time, even if the excitation light is condensed and the amount of heat generated is large, the amount of heat radiation is large, and the divergence of light inside the phosphor, the reflection of the excitation light on the phosphor surface, and the reflection of the fluorescence light surface are reduced. A light source device with high luminous efficiency is provided.

  According to the present invention described above, a light source device that excites a phosphor with blue light as excitation light has high luminous efficiency, can be manufactured at low cost, and can be realized as a small-sized and easily modularized light source device. Thus, a headlight device for a vehicle and a light source device for a projector that is excellent in environmental protection and has a long life can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration (a) in which a vehicle headlight device as a first embodiment of a light source device of the present invention is applied as a headlight of an automobile, and a perspective view (b) of a light source unit. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration (a) of a vehicle headlight device as a first embodiment of a light source device of the present invention, and a cross-sectional view (b) illustrating a light source unit thereof. FIG. 6 is a diagram illustrating an overall configuration of a projector as a second embodiment of the light source device of the present invention. 6 is a first embodiment of a light source unit of an illumination optical system of a projector. 9 is a second embodiment of the light source unit of the illumination optical system of the projector. FIG. 11 is a diagram illustrating a modification in which a total reflection lens is used as a reflector in the first embodiment of the light source unit of the illumination optical system of the projector. FIG. 3 is a detailed cross-sectional view showing the principle of a light source unit according to the present invention, showing an embodiment of an excitation light reflection type in which excitation light is incident from the same direction as the emission direction of fluorescent light. FIG. 3 is a detailed cross-sectional view illustrating the principle of a light source unit according to the present invention, showing an embodiment of an excitation light transmission type in which excitation light is incident from a direction different from the emission direction of fluorescent light. FIG. 3 is a detailed cross-sectional view showing a light source unit according to the present invention, showing an embodiment of an excitation light reflection type in which excitation light is made incident from the same direction as the emission direction of fluorescent light. FIG. 3 is a detailed cross-sectional view showing a light source unit according to the present invention, showing an embodiment 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 the principle of a light source unit according to the present invention, showing an embodiment of an excitation light reflection type in which excitation light according to the prior art is made to enter from the same direction as the emission direction of fluorescent light. FIG. 4 is a detailed cross-sectional view showing the principle of a light source unit according to the present invention showing an embodiment of an excitation light transmission type in which excitation light according to the related art is made to enter from a direction different from the emission direction of fluorescent light. FIG. 3 is a diagram illustrating a relationship between an incident angle and a reflection angle of excitation light on a phosphor. It is a figure which shows an example of the angle characteristic of the reflectance with respect to the substance of the refractive index 1.5 with respect to 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 angle dependence of excitation light on the output of fluorescent light. FIG. 4 is a characteristic diagram showing the dependence of the excitation light on the incident angle to the phosphor, which is an example of the present invention. It is a figure which shows the light conversion efficiency with respect to the incident angle to the phosphor layer for every polarization direction of excitation light. It is a figure which shows the ratio of the light conversion efficiency by the polarization direction with respect to the excitation light incident angle with respect to a phosphor layer.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following description, and various changes and modifications by those skilled in the art are possible within the scope of the technical idea disclosed in the present specification. In the drawings for describing the present invention, components having the same function are denoted by the same reference numerals, and a repeated description thereof may be omitted.

  First, FIG. 1 shows a vehicle 1 equipped with a vehicle headlight device using a solid-state light emitting device according to an embodiment of the present invention by a perspective view and a partially enlarged view thereof. FIG. 1A shows an entire vehicle 1 on which a vehicle headlight device 1000 of the present invention is mounted, and FIG. 1B shows an enlarged view of a headlight device portion of the vehicle. .

  FIG. 2A is a side cross-sectional view of the headlight device 1000 shown in FIG. 1B, and FIG. 2B shows a structural cross-section of the light source portion. In addition, FIG. 3 employs the light source device according to an embodiment of the present invention as a light source, that is, information including the traveling direction of the vehicle in front of the vehicle using the light source device of the headlight device. FIG. 1 is a diagram illustrating an overall structure of a vehicle projector for projecting and displaying.

(Example 1)
As shown in these drawings, the headlight device 1000 shown in FIG. 1 basically transmits a visible light illumination unit 10 as a light source device and illumination light emitted from the illumination unit to a space in front of the vehicle 1. And an optical system for irradiating on a road surface on which the vehicle 1 travels, and includes a so-called projector lens 51. Further, the projection optical property may be configured by using a reflection mirror 60 instead of the projector lens 51. Alternatively, as illustrated in FIG. By doing so, the distribution of the irradiation light on the road surface may be controlled with high accuracy, and the volume of the entire headlight device may be reduced.

  As apparent from these figures, in the headlight device 1000 according to the present invention, the illumination light from the visible light illumination unit 10 emits the fluorescent light by irradiating the excitation light from the excitation light source 12 to the phosphor. Is obtained. In the light source device, for example, when white light is obtained, as shown in FIG. 2B, the phosphor 19 excited by the blue light flux 13 as the excitation light from the excitation light source 12 is yellow or green and red. , And white light can be obtained by mixing with excitation light blue. That is, it is preferable to emit a light beam in a wavelength region having a complementary color relationship with the excitation light with respect to white. The obtained irradiation light beam is bent in a predetermined direction by the reflection mirror 60 as shown in FIG. This allows more precise control of the irradiation direction and intensity depending on the degree of freedom of the shape of the reflecting surface.

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

<Light source unit>
In order to obtain white light, the visible light illumination unit 10 which is a light source device of the present invention has one or a plurality of solid-state light sources, which will be described later, such as a semiconductor light source element LED (Light Emitting Diode) or LASER ( Using Light Amplification by Stimulated Emission of Radiation, a desired white light is obtained by mixing the excitation light with the light obtained by exciting the phosphor 19 that emits yellow or green and red light. As shown in FIG. 2B, a method of irradiating the mixed color light from the emission direction to reflect the fluorescent light and the excitation light on the reflection surface 17 and emit the light in a desired direction (hereinafter referred to as a “reflection method”). There is a method in which an excitation light source is arranged on the bottom surface of the groove in which the phosphor 19 is arranged (not shown, hereinafter referred to as a “transmission method”), but a transmission method is adopted to make the entire headlight device compact. Often.

  Hereinafter, focusing on the reflection method shown in FIG. 2B and for convenience of explanation, the structure and effect obtained in a method using blue laser light as the excitation light will be described.

The inventors have derived through experiments that the following three factors are effective in efficiently obtaining light source light from the light source unit.
(1) The phosphor is efficiently irradiated with the excitation light 13 from the excitation light source 12.
(2) The fluorescence generated by the phosphor 19 is efficiently emitted in a desired direction.
(3) Increase the luminous efficiency of the phosphor.

  In order to realize the above (1), the phosphor layer including the phosphor 19 is irradiated with the excitation light flux 13. At this time, an antireflection film 21 is provided on the surface of the phosphor layer to reduce reflection on the surface. Further, for the excitation light 13, the output of the fluorescent light was obtained by experiment with respect to the same input energy of the excitation light as shown in FIG. 13 showing the relationship between the incident angle to the phosphor layer and the reflection angle. As a result, as shown in FIG. 19, it was found that light conversion efficiency (outgoing light energy / incident light energy) was higher when using P-polarized light than when using S-polarized light. FIG. 20 shows the ratio between the efficiency when using P-polarized light and the light conversion efficiency when using S-polarized light, using the incident angle of the excitation light as a parameter. It was found that the P-polarized light had higher efficiency, and the efficiency was highest near the incident angle of 30 degrees. This is due to 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 have changed the configuration of the phosphor layer to the configuration according to the prior art in which a gap exists between the phosphor 19 and the binder 23 shown in FIGS. 11 and 12, and as shown in FIGS. In order to greatly reduce the density of the voids, the phosphor 19 and the binder 23 are baked to adopt a structure for preventing reflection at the phosphor-vacuum (or air) interface. At this time, as the phosphor used, LuAG: Ce (refractive index: 1.85) was used as the green light-emitting phosphor, YAG: Ce (refractive index: 1.82) was used as the yellow phosphor, and the binder was: A comparative study was conducted using aluminum oxide (alumina) (refractive index 1.76) and titanium oxide (refractive index 2.5) having high transparency and thermal conductivity. As a result, when aluminum oxide having a small difference in the refractive index between the phosphor 19 and the binder 23 is used as the binder 23, the method according to the prior art in which the generation of the scattered light 21 inside the phosphor is reduced is provided. 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 (2), as shown also in FIGS. 9 and 10, groove portions 16 are provided in the structures 15 and 18 on which the phosphor layers are provided, and the opening shape of the groove portions 16 is In the cross-sectional direction, a cross-sectional shape (a so-called “mortar shape”) in which a part or the whole decreases in the depth direction. At this time, by providing the reflective films 17 and 20 having a visible light reflectance of 90% or more on the contact surface between the structure 18 and the phosphor 19, light obtained in a desired direction can be emitted. Further, when the phosphor 19 and the binder are fired on the structure 18, shrinkage occurs during cooling. As a result, an air or vacuum interface is generated between the reflecting surface and the phosphor layer. However, since the average refractive index of the phosphor layer is about 1.75, some light is totally reflected and is directed in a desired direction. Since the light is emitted, light can be efficiently extracted for the subsequent optical system.

  Finally, with regard to the technical means for realizing the above (3), the inventors investigated the relationship between the phosphor temperature and the light conversion efficiency in the state where the excitation light was irradiated, and found that the light conversion by increasing the temperature of the phosphor. We found that the efficiency declined. Therefore, in order to reduce the phosphor temperature, the above-mentioned structure is made of a metal having high thermal conductivity, and the reflection surface of the groove portion is made of aluminum or silver alloy having high reflectance even with a metallic reflection 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 fired and thermally bonded, so that the temperature rise of the phosphor due to the excitation light is reduced, and high efficiency is realized.

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

  As described above, in order to obtain white light, the visible light illumination unit 10 as the light source device of the present invention employs, as the excitation light source 12, one or a plurality of solid-state light sources described later, such as a semiconductor light source element LED (Light Emitting Diode) or LASER. By using (Light Amplification by Stimulated Emission of Radiation), a desired white light is obtained by mixing the excitation light and the light obtained by exciting the phosphor 19 emitting yellow or green and red. Further, as shown in FIG. 2B, in the embodiment, the fluorescent light and the excitation light are irradiated from the mixed color emission direction to be reflected by the reflection surfaces 17 and 20, and emitted in a desired direction. The method (hereinafter referred to as “reflection method”) has been described. However, the present invention is not limited to these. As shown in FIGS. 8 and 10, in a transmission system in which an excitation light source is disposed on the bottom surface of a groove in which a phosphor 19 is disposed, the excitation light beam φ2 is incident on the incident side. The reflection loss is reduced by providing an antireflection film on the light exit surface from which a part of the fluorescence light and the excitation light are mixed and emitted. In these examples, there is no other difference in the configuration, and it goes without saying that the same effect can be obtained with the same configuration.

(Example 2)
<Projector>
Hereinafter, a vehicle projector employing a light source unit as a light source according to another embodiment of the present invention will be described with reference to FIG. This figure shows the entire configuration of the projector. In particular, a system in which light intensity modulation according to a video signal is performed by a so-called transmissive liquid crystal panel will be described. In the figure, R, G, and B indicating the color light are attached after the reference numerals to distinguish the elements arranged in the optical path of each color light, and the suffix of the color light is omitted when there is no need to distinguish. In addition, in order to clarify the polarization direction, the drawing will be described using a right-handed orthogonal coordinate system in FIG. That is, the optical axis 101 is the Z axis, the axis parallel to the plane of FIG. 3 in the plane perpendicular to the Z axis is the Y axis, the axis from the back of the plane of the figure to the front is the X axis, and the plane parallel to the Y axis is the plane. A direction parallel to the Y direction and the X axis is referred to as an X direction. In order to further distinguish the polarization directions, the polarized light having the X direction is referred to as X polarized light, and the polarized light having the Y direction is referred to as Y polarized light.

  3, the optical system of the projector includes an illumination optical system 100, a light separation 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 a light combining means, and a projection lens 300 as a projection means. The liquid crystal panel 60 includes an incident-side polarizing plate 50 (50R, 50G, 50B) on the light incident side, and includes an output-side polarizing plate 80 (80R, 80G, 80B) on the light emitting side. These optical elements are mounted on a base 550 to form an optical unit 500. The optical unit 500 is mounted on a housing (not shown) together with a drive circuit 570 for driving the liquid crystal panel 60, a cooling fan 580 for cooling the liquid crystal panel 60 and the like, and a power supply circuit 560 for supplying power to each circuit. Constitute.

  Hereinafter, the details of each unit constituting the projector described above will be described. The illumination optical system 100 for uniformly irradiating the liquid crystal panel 60 as a video display element includes the above-described visible light illumination unit 10 composed of a solid-state light-emitting element that emits substantially white light, and first and second lenses that constitute an optical integrator. It is configured to include arrays 21 and 22, a polarization conversion element 25, and a condenser lens (superimposed lens) 27.

  The photodecomposition optical system 30 for photodecomposing substantially white light from the illumination optical system 100 into three primary color lights includes two dichroic mirrors 31 and 32 and a reflection mirror 33 for changing the direction of an 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 turning mirrors 45 and 46.

  In such a configuration, a light beam substantially parallel to the optical axis 101 indicated by a broken line in FIG. 3 is emitted from the light source unit 10 including the solid state light emitting elements. Then, the light emitted from the light source unit 10 enters the polarization conversion integrator. The polarization conversion integrator includes an optical integrator for realizing uniform illumination comprising a first array lens 21 and a second array lens 22, and a polarization for aligning the polarization direction of light to a predetermined polarization direction and converting the light to linearly polarized light. And a polarization conversion element 25 composed of a beam splitter array. That is, in the above-described polarization conversion integrator, 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 linearly polarized light.

  Then, the projection images of the respective 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 way, the liquid crystal panel is uniformly illuminated while aligning the light having a random polarization direction from the solid-state light source with a predetermined polarization direction (here, X-polarized light).

  On the other hand, the light separation optical system 30 separates the substantially white light emitted from the illumination optical system 100 into B light (light in a blue band), G light (light in a green band), and R light (light in a red band). Then, the light is guided to each optical path (B optical path, G optical path, and R optical path) toward the corresponding liquid crystal panel 60 (60R, 60G, 60B). That is, the B light reflected by the dichroic mirror 31 is reflected by the reflection mirror 33, passes through the field lens 29B and the incident side polarization plate 50B, and enters the liquid crystal panel 60B for B light (B optical path). The G light and the R light pass through the dichroic mirror 31 and are separated by the dichroic mirror 32 into G light and R light. The G light is reflected by the dichroic mirror 32 and enters the G light liquid crystal panel 60G through the field lens 29G and the incident side polarization plate 50G (G light path). The R light passes through the micro mirror 32 and enters the relay optical system 40. The R light incident on the relay optical system 40 is condensed (converged) near the second relay lens 42 via the reflection 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 R light liquid crystal panel 60R (R light path).

  Each of the liquid crystal panels 60 (60R, 60G, 60B) constituting the light intensity modulator is driven by the drive circuit 570, and the degree of polarization is increased by the incident side polarizing plate 50 (50R, 50G, 50B) having the transmission axis in the X direction. The X-polarized color light incident from the light separation optical system 30 is modulated according to a color image to form a Y-polarized optical image.

  The Y-polarized optical image of each color light formed as described above is incident on the output polarizer 80 (80R, 80G, 80B). The incident-side polarizing plates 80R, 80G, and 80B are polarizing plates having the transmission axis in the Y direction, whereby unnecessary polarization components (here, X-polarized light) are removed, and the contrast is improved. The optical image of each color light formed by the above-described method is incident on a synthesizing prism 200 which is a light synthesizing means, is synthesized to obtain a color image, and is enlarged and projected by a projection lens 300 on, for example, a running road surface.

<Light source unit for projector>
FIG. 4 is a diagram for explaining the principle of the light source unit 10 of the vehicle projector, as another configuration of the solid-state light source device according to one embodiment of the present invention. 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 a blue band (color B), which are light-emitting sources of solid-state elements, are arranged on a substantially disk-shaped substrate. A reflecting mirror (reflector) 130 having, for example, a parabolic surface, which is arranged at an angle of approximately 45 degrees so as to face the laser light emitting surface of the element group 110, and rotates near the focal point (F) of the reflecting mirror. A disk (wheel) member 140 to be driven and driving means for rotating the member at a desired rotation speed, for example, an electric motor 150 are provided.

  A light source unit according to a second embodiment of the present invention will be described with reference to FIG. The first reflecting mirror (reflector) 130 has a smaller diameter than the second reflecting mirror (reflector) 130 ′, and white light can be obtained from the first reflecting mirror (reflector) 130. Excitation light from the semiconductor laser element group 110 is incident on the outer periphery of the disk (wheel) member 140. A spherical reflector 149 is provided for reflecting light that does not reach the reflecting surface 131 of the reflecting mirror (reflector) 130 from the vicinity of the focal point F. According to 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 reflecting mirror (reflector) 130, so that the light use efficiency can be improved. The emission direction of the emission light from the phosphor 19 can be controlled by providing a fine concave portion having a mortar-shaped cross section shown in FIGS. 9 and 10 on the emission side surface (upper surface) of the base material 142 ′. The energy conversion efficiency is improved by increasing the light capture rate of the illumination optical system (not shown) at the subsequent stage.

  In the above description, the fluorescent surface and the reflection / diffusion surface or the transmission / diffusion surface formed on the base material are sequentially switched over time with respect to the excitation light collected from the reflector (reflector) in the vicinity of the focal point F. By rotating the surface of the substrate on the disk in a plurality of segments, the heat radiation effect can be improved and the damage to the phosphor can be reduced. However, the present invention is not limited to this. For example, a surface of a rectangular substrate having a rectangular shape and a reflection / diffusion surface or a transmission / diffusion surface are formed and vibrated at a specific period or an irregular period. Alternatively, by adopting a structure in which the relative position with respect to the focal point F can be changed, damage to the phosphor due to the excitation light being condensed at one point of the phosphor can be reduced.

  FIG. 6 shows a configuration using a so-called total reflection lens 135 in which a total reflection surface and a condenser lens are formed as a single member as a reflection mirror (reflector). According to this configuration, the excitation light (blue laser beam) near the optical axis passes through the condenser lens 136, while the excitation light (blue laser beam) at a position away from the optical axis is totally reflected by the total reflection unit 137. The light is reflected, and all the light rays are condensed at one point on the disk (wheel) member 140, and then reflected and diffused as blue light or converted to yellow light and diffused. Then, among the blue light and the yellow light diffused from one point of the disk (wheel) member 140, the light rays near the optical axis pass through the condenser lens 136 again, and all the light rays become parallel to the optical axis. Further, the light is reflected by the separation mirror 120 and enters the illumination optical form 100 of the projector. In addition, a reflection film may be formed on the surface of the total reflection section 137, and the surface shape of the reflection mirror 137 has a curved surface such as a parabolic surface or an elliptical surface similarly to the above-mentioned reflector (reflector). (Surface) is desirable. That is, even with this configuration, similarly to the above, white illumination light can be obtained, and the influence of focal shift (on-axis chromatic aberration) due to color can be suppressed to a level at which there is no practical problem.

  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 side of the excitation (blue laser) light source of the substrate 121, and reflects light on the opposite side. A dichroic coat that transmits blue light and reflects yellow light is deposited on the mirror (reflector) side. The blue laser light adjusted to the P-polarized light enters the separation mirror, passes through the polarization separation coat surface dichroic coat surface, and enters the reflection mirror (reflector). The excitation light (blue laser light) incident on the reflector is focused on one point of the disk (wheel) member, and part of the blue light excites the phosphor to emit yellow light, and part of the blue light The light is rotated by 90 degrees to be S-polarized and diffused. After that, the light becomes parallel by a reflecting mirror (reflector), and the yellow light and the blue light adjusted to S-polarized light again enter the separation mirror 120.

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

  In addition, the light source unit described above is not limited to the light source unit for the projector of the vehicle described above, and may 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 above-described light source unit, light obtained by exciting the phosphor 19 that emits yellow or green and red using the semiconductor light source element LED or LASER is mixed with the excitation light. Thus, it is possible to obtain a solid-state light source device that can obtain a desired white light and is excellent in light emission intensity and heat radiation effect. In addition, the light source unit is not limited to a vehicle projector, and can be used as a light source of a general projector that projects and displays various images on a surface such as a screen. It will be clear to those skilled in the art.

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

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 1000 ... Headlight device, 10 ... Visible light illumination unit, 12 ... Excitation light source, 13 ... Excitation light (blue luminous flux), 17 ... Reflection surface, 15, 18 ... Structure, 17, 20 ... Reflection film, 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: incident side polarizing plate, 60: liquid crystal panel, 80: output side polarizing plate, 100: illumination optical system, 200: photosynthetic prism, 300: projection lens, 500: optical unit, 550 ... Substrate, 560 ... Power supply circuit, 570 ... Drive circuit, 580 ... LED collimator unit outside cooling fan, 51 ... Projector lens, 60 ... Reflection mirror

Claims (10)

A vehicle headlight device attached to a part of a vehicle and irradiating illumination light on a road surface on which the vehicle travels,
Equipped with a light source device,
The light source device that generates the illumination light includes a phosphor layer coated with a phosphor, and an excitation light source that excites the phosphor.
A headlight device, wherein the excitation light from the excitation light source is configured to irradiate the phosphor layer with light having a specific polarization at an incident angle in a range of 40 degrees to 70 degrees with respect to the phosphor layer.   The headlight device according to claim 1, wherein the phosphor layer is formed by firing the phosphor and a binder, and P-polarized light is used as the excitation light.   The headlight device according to claim 1, wherein YAG: Ce (refractive index 1.82) is used as the phosphor, and a member having a refractive index difference of 0.2 or less from the phosphor is used as a binder. A vehicle headlight device attached to a part of a vehicle and irradiating illumination light on a road surface on which the vehicle travels,
Equipped with a light source device,
The light source device that generates the illumination light includes a phosphor layer coated with a phosphor, and an excitation light source that excites the phosphor.
The structure to which the phosphor constituting the light source device that generates the illumination light is applied has a groove portion in which the phosphor layer is provided, and an opening shape of the groove portion is directed to a depth direction in a cross-sectional direction. A reflection film having a reflectance of 90% or more for visible light is provided on a contact surface between the structure and the phosphor layer, and an air-side interface of the phosphor layer is provided on a contact surface between the structure and the phosphor layer. A headlight device formed by forming an anti-reflection film.   The headlight device according to claim 4, wherein an interface of air or vacuum is provided between the structure, the phosphor layer obtained by firing the phosphor with a binder, and the reflective film. A solid-state light-emitting portion that generates excitation light, light-condensing means that condenses the excitation light from the solid-state light-emitting portion in a point-like manner, in the vicinity of the focal point of the excitation light condensed in a point-like manner by the light-condensing means, A reflection scattering / fluorescence emission unit that alternately repeats the reflection scattering of the excitation light and the emission of the fluorescence light excited by the excitation light; and the excitation light reflected by the reflection scattering / fluorescence emission unit and the reflection scattering / fluorescence emission unit. Output means for extracting the excitation light whose wavelength has been converted by the fluorescent light emitting means on the same optical path and outputting white light emitted from a substantially point-like light source,
The solid-state light-emitting unit includes a phosphor layer coated with a phosphor, and an excitation light source that excites the phosphor.
The solid-state light source device, wherein the excitation light from the excitation light source irradiates the phosphor layer with light having a specific polarization at an incident angle in a range of 40 degrees to 70 degrees with respect to the phosphor layer.   The solid-state light source device according to claim 6, wherein the solid-state light emitting unit is configured by arranging a plurality of semiconductor laser elements in a plane.   The solid-state light source device according to claim 6, wherein the emission color of the phosphor emits a light flux in a wavelength region that has a complementary color relationship with the excitation light with respect to white.   The solid-state light source device according to claim 8, wherein the excitation light from the solid-state light emitting unit is blue light whose polarization plane is aligned in one direction.   The solid-state light source device according to claim 6, wherein the phosphor layer is formed by firing the phosphor and a binder, and uses P-polarized light as the excitation light.

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