JP2022066298A - Light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device which reduces color shading and light emission irregularity while suppressing conversion efficiency of a phosphor part from decreasing.

SOLUTION: A light-emitting device according to the present invention comprises a semiconductor laser element 10, a light reflection part 20 provided with a light reflection surface 21, and a phosphor part 30 having a light irradiation surface. A region, irradiated with radiant light, of the light reflection surface 21 has a first region 21a and a second region 21b, which are so provided that on the light irradiation surface of the phosphor part 30, radiant light, reflected on a side close to the second region 21b, of radiant light reflected in the first region 21a and radiant light, reflected on a side far away from the first region 21a, of radiant light reflected in the second region 21b overlap each other and radiant light, reflected on a side far away from the second region 21b, of the radiant light reflected in the first region 21a and radiant light, reflected on a side close to the first region 21a, of the radiant light reflected in the second region 21b overlap each other.

SELECTED DRAWING: Figure 5

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a light emitting device.

The light emitting device described in Patent Document 1 includes a semiconductor laser element, a mirror member on which a total reflection film is formed, and a fluorescent unit arranged above the mirror member. The synchrotron radiation from the semiconductor laser element is reflected by the fluorescent unit by a total reflection mirror provided on the mirror member (see, for example, FIG. 3 of Patent Document 1).

JP-A-2010-251686

In such a light emitting device, the light intensity of the synchrotron radiation radiated to the light irradiation surface of the fluorescent portion is higher in the central portion than in the surroundings. In this case, the calorific value of the fluorescent portion irradiated with the central portion of the synchrotron radiation increases, which may reduce the conversion efficiency of the fluorescent portion. In addition, there is a possibility that the emission intensity and color unevenness of the light extracted from the fluorescent portion may occur.

The light emitting device according to one embodiment of the present invention comprises a semiconductor laser element having an elliptical farfield pattern of emitted light, a light reflecting portion provided with a light reflecting surface for reflecting the emitted light, and the light reflecting surface. It has a light irradiation surface to which the reflected emitted light is irradiated, and includes a fluorescent unit that emits fluorescence when the emitted light is irradiated to the light irradiation surface. In this light emitting device, the region on the light reflecting surface to be irradiated with the radiated light is the first region corresponding to one end of the region obtained by dividing the elliptical furfield pattern into two or more in the longitudinal direction. It has a region and a second region corresponding to a region located at the other end, and the first region and the second region are radiation reflected in the first region on the light irradiation surface of the fluorescent unit. The radiated light reflected on the side of the light near the second region and the radiated light reflected on the side of the radiated light reflected in the second region far from the first region are overlapped with each other. , The radiated light reflected in the first region on the side far from the second region and the radiated light reflected in the second region on the side closer to the first region. It is provided so as to overlap with the reflected radiant light.

The light emitting device according to another embodiment of the present invention includes a semiconductor laser element having an elliptical farfield pattern of emitted light, a light reflecting portion provided with a light reflecting surface for reflecting the emitted light, and the light reflecting surface. It has a light irradiation surface on which the radiation light reflected in the above is irradiated, and includes a fluorescent unit that emits light when the light irradiation surface is irradiated with the radiation light. In this light emitting device, the region on the light reflecting surface to be irradiated with the radiated light is a region in which the elliptical furfield pattern is divided into three in the longitudinal direction, and is a first region corresponding to a region located at one end. It has a second region corresponding to a region located at the other end and a third region located between the first region and the second region, and the first region is the light of the fluorescent unit. On the irradiation surface, the radiated light reflected in the first region is the radiated light reflected in the side closer to one of the first region or the second region of the radiated light reflected in the third region. The second region is provided so as to overlap, and the radiated light reflected in the second region on the light irradiation surface of the fluorescent unit is the second of the radiated light reflected in the third region. It is provided so as to overlap with the radiated light reflected on the side close to the other of one region or the second region.

The light emitting device according to another embodiment of the present invention includes a semiconductor laser element having an elliptical farfield pattern of emitted light, a light reflecting portion provided with a light reflecting surface for reflecting the emitted light, and the light reflecting surface. It has a light irradiation surface on which the radiation light reflected in the above is irradiated, and includes a fluorescent unit that emits light when the light irradiation surface is irradiated with the radiation light. In this light emitting device, the light reflecting surface is a curved surface, and corresponds to regions located at both ends in the longitudinal direction of the elliptical farfield pattern so that the intensity distribution of the emitted light on the light irradiation surface approaches uniformly. The divergence angle of the radiated light reflected in the region is provided so as to be smaller than the divergence angle of the radiated light reflected in the region corresponding to the region located at the center in the longitudinal direction.

According to the light emitting device according to each form, it is possible to reduce the decrease in the conversion efficiency of the fluorescent unit and to reduce the color unevenness and the light emitting unevenness of the light extracted from the fluorescent unit.

FIG. 1 is a perspective view of a light emitting device according to the first embodiment. FIG. 2 is a top view of the light emitting device according to the first embodiment. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. FIG. 4 is a perspective view of an optical element included in the light emitting device according to the first embodiment. FIG. 5 illustrates the movement of the synchrotron radiation until the synchrotron radiation emitted from the semiconductor laser element is reflected by the light reflecting surface and irradiated to the light irradiation surface of the phosphor in the light emitting device according to the first embodiment. It is a figure for. FIG. 6 is a diagram measured by simulating the light intensity distribution of the synchrotron radiation reflected by the conventional light reflecting surface. FIG. 7 is a diagram showing the light intensity distribution in the straight line connecting VII and VII of FIG. FIG. 8 is a perspective view for explaining the inside of the recess of the substrate in the light emitting device according to the first embodiment. FIG. 9 is a top view for explaining the inside of the recess of the substrate in the light emitting device according to the first embodiment. FIG. 10 is a diagram obtained by simulating and measuring the light intensity distribution of synchrotron radiation on the light irradiation surface of the fluorescent portion in the light emitting device according to the first embodiment. FIG. 11 is a diagram showing the light intensity distribution in the straight line connecting XI and XI in FIG. FIG. 12 is a diagram obtained by simulating the light intensity distribution of the synchrotron radiation reflected in the first region on the light irradiation surface of the fluorescent portion in the light emitting device according to the first embodiment. FIG. 13 is a diagram showing the light intensity distribution in the straight line connecting XIII-XIII in FIG. FIG. 14 is a diagram obtained by simulating the light intensity distribution of the synchrotron radiation reflected in the second region on the light irradiation surface of the fluorescent portion in the light emitting device according to the first embodiment. FIG. 15 is a diagram showing the light intensity distribution in the straight line connecting XV-XV of FIG. FIG. 16 is a diagram obtained by simulating the light intensity distribution of the synchrotron radiation reflected in the third region on the light irradiation surface of the fluorescent portion in the light emitting device according to the first embodiment. FIG. 17 is a diagram showing the light intensity distribution in the straight line connecting XVII-XVII of FIG. FIG. 18 is a cross-sectional view for explaining the light emitting device according to the second embodiment. FIG. 19 is a perspective view for explaining the inside of the recess of the substrate in the light emitting device according to the third embodiment. FIG. 20 is a top view for explaining the inside of the recess of the substrate in the light emitting device according to the third embodiment. FIG. 21 is a diagram obtained by simulating and measuring the light intensity distribution of synchrotron radiation on the light irradiation surface of the fluorescent portion in the light emitting device according to the third embodiment. FIG. 22 describes the movement of the synchrotron radiation until the synchrotron radiation emitted from the semiconductor laser element is reflected by the light reflecting surface and irradiated to the light irradiation surface of the fluorescent portion in the light emitting device according to the fourth embodiment. It is a figure for. FIG. 23 describes the movement of the synchrotron radiation until the synchrotron radiation emitted from the semiconductor laser element is reflected by the light reflecting surface and radiated to the light irradiation surface of the fluorescent portion in the light emitting device according to the fifth embodiment. It is a figure for.

A mode for carrying out the present invention will be described below with reference to the drawings. However, the embodiments shown below are for embodying the technical idea of the present invention and do not limit the present invention. The size and positional relationship of the members shown in each drawing may be exaggerated for the sake of clarity.

<First Embodiment>
FIG. 1 shows a perspective view of the light emitting device 200 according to the first embodiment, FIG. 2 shows a top view of the light emitting device 200, and FIG. 3 shows a cross-sectional view taken along the line III-III of FIG. Further, FIG. 4 is a perspective view of the optical element 20 which is the light reflecting unit 20 in the light emitting device 200. Further, FIG. 5 is for explaining the movement of the synchrotron radiation in the light emitting device 200 until the synchrotron radiation emitted from the semiconductor laser element 10 is reflected by the light reflecting surface 21 and irradiated to the light irradiation surface of the fluorescent unit 30. It is a figure of.

As shown in FIGS. 1 to 5, the light emitting device 200 reflects the synchrotron radiation to the semiconductor laser element 10 having an elliptical far field pattern (hereinafter referred to as “FFP (Far Field Pattern)”). It has a light reflecting unit 20 provided with a light reflecting surface 21 and a light irradiation surface on which the synchrotron radiation reflected by the light reflection surface 21 is irradiated, and fluorescence is emitted by irradiating the light irradiation surface with the synchrotron radiation. A fluorescent unit 30 that emits light is provided. In the light emitting device 200, the region to be irradiated with the synchrotron radiation on the light reflecting surface 21 is the first region 21a corresponding to the region located at one end of the regions in which the elliptical FFP is divided into two or more in the longitudinal direction. It has a second region 21b corresponding to a region located at the other end. Further, the first region 21a and the second region 21b are the radiated light reflected on the light irradiation surface of the fluorescent unit 30 on the side of the radiated light reflected by the first region 21a closer to the second region 21b. The radiated light reflected in the second region 21b overlaps with the radiated light reflected on the side far from the first region 21a, and at the same time, from the second region 21b of the radiated light reflected in the first region 21a. The radiated light reflected on the distant side and the radiated light reflected on the side closer to the first region 21a of the radiated light reflected in the second region 21b are provided so as to overlap each other.

According to the light emitting device 200, it is possible to reduce the emission intensity unevenness and the color unevenness of the light extracted from the fluorescent unit 30 while reducing the decrease in the conversion efficiency of the fluorescent unit 30. This point will be described below.

The emitted light of the semiconductor laser element 10 (hereinafter referred to as “LD (Laser Diode) element 10”) is the length in the stacking direction of a plurality of semiconductor layers including the active layer on a surface parallel to the light emitting surface of the LD element 10. It has an elliptical FFP whose length is longer than its length perpendicular to it. The FFP referred to here is a measurement of the light intensity distribution of synchrotron radiation on a surface that is separated from the light emitting surface of the LD element 10 to some extent and is parallel to the light emitting surface, and is, for example, 1 / from the peak intensity value. It is specified as a shape in strength when it drops to an arbitrary strength such as ^e2 . At this time, in the synchrotron radiation, the intensity of the central portion in the ellipse is higher than the intensity of the portion far from the central portion in the ellipse. In the conventional light emitting device, for example, the synchrotron radiation emitted from the LD element is reflected by the light reflecting surface inclined by 45 degrees to irradiate the light irradiation surface of the fluorescent portion. In this case, the light irradiation surface of the fluorescent portion is irradiated while maintaining the light intensity distribution of FFP. This is clear from the results of simulation and measurement of the light intensity distribution of the light irradiation surface in the conventional light emitting device shown in FIGS. 6 and 7. FIG. 7 is a diagram showing the light intensity distribution in the straight line connecting VII and VII of FIG. 6, in which the light intensity at the central portion is clearly higher than the light intensity at the edge portion. When this light is applied to the fluorescent portion, the calorific value of the fluorescent portion in the region where the light intensity is high becomes larger than the calorific value of the surroundings, so that the conversion efficiency of the fluorescent portion is lowered. Further, due to the difference in the intensity of the synchrotron radiation radiated to the fluorescent portion, there is a possibility that the light emitting device has uneven emission intensity and uneven color.

Therefore, in the light emitting device 200, the region where the radiated light is irradiated on the light reflecting surface 21 is first so that the radiated light reflected by the light reflecting surface 21 approaches a uniform light intensity distribution on the light irradiating surface of the fluorescent unit 30. One region 21a and a second region 21b are provided. At this time, as shown in FIG. 5, the first region 21a and the second region 21b are the radiated light having a low emission intensity among the radiated light reflected in the first region 21a (the first region 21a shown in FIG. 5). (Radiation light reflected near the left end) and radiation with high emission intensity among the radiation reflected in the second region 21b (radiation light reflected near the left end of the second region 21b shown in FIG. 5). , And of the radiated light reflected in the first region 21a, the radiated light with high emission intensity (radiated light reflected near the right end of the first region 21a shown in FIG. 5) and the second region 21b. Of the reflected radiated light, the radiated light having a low emission intensity (the radiated light reflected near the right end of the second region 21b shown in FIG. 5) is provided so as to overlap with each other. As a result, the light intensity distribution of the synchrotron radiation radiated to the light irradiation surface of the fluorescence unit 30 can be made uniform, so that the decrease in the conversion efficiency of the fluorescence unit 30 can be reduced, and the unevenness of the emission intensity and the color unevenness can be reduced. It can be a light emitting device.

Hereinafter, the components of the light emitting device 200 will be described.

(Hypokeimenon 40)
The substrate 40 mounts the LD element 10. In FIG. 3, a substrate 40 provided with a recess is used, and the LD element 10 is arranged on the bottom surface of the recess.

As the substrate 40, one containing ceramics can be used. Examples of the ceramics include aluminum oxide, aluminum nitride, silicon nitride, and silicon carbide. When the substrate 40 and the lid 80 are fixed by welding, the portion in contact with the lid 80 (welded portion 43) is made of a material containing iron as a main component.

As shown in FIGS. 8 and 9, the substrate 40 provided with the recess includes a main body 41 made of an insulator, and wiring portions 42a and 42b exposed from the main body 41 on the upper surface of the substrate 40 and the bottom surface of the recess. It has a welded portion 43 in contact with the lid 80. By exposing the wiring portion 42a electrically connected to the outside from a surface other than the lower surface of the main body 41, the entire lower surface of the substrate 40 can be used as a surface to be mounted on another member such as a heat sink, so that light is emitted. The heat generated by the device 200 is easily dissipated to the heat sink.

As the substrate, a substrate having a base portion and a frame portion arranged on the upper surface of the base portion may be used. In this case, the LD element is arranged on the upper surface of the base portion and inside the frame portion. At this time, it is preferable that the wiring portion is provided on the upper surface of the base portion on the outside of the frame portion in consideration of the heat dissipation of the light emitting device.

(Semiconductor laser element 10)
The LD element 10 has an FFP whose synchrotron radiation has an elliptical shape. The LD element 10 is arranged so that its light emitting surface is perpendicular to the lower surface of the substrate 40 and the longitudinal direction of the ellipse of the FFP is perpendicular to the lower surface of the substrate 40. As a result, the surface of the LD element 10 having a large area can be arranged in parallel with the lower surface of the substrate 40, so that the heat generated by the LD element 10 is easily dissipated to the substrate 40 and the heat sink. It should be noted that the term "vertical" here includes the inclination due to the degree of deviation at the time of mounting.

As the LD element 10, one having an emission peak wavelength in the range of 320 nm to 530 nm, typically 430 nm to 480 nm can be used. Since the LD element 10 in the above range is synchrotron radiation of relatively high energy, the conversion efficiency of the fluorescent unit 30 is likely to decrease, and the effect of adopting the light reflecting surface 21 or the like of the present embodiment is remarkable. This is to become. As the LD element 10 in the above range, for example, it is preferable to use a material containing a nitride semiconductor, and examples thereof include those containing at least one of GaN, InGaN, and AlGaN.

The LD element 10 is mounted on the substrate 40 via the submount 50. As a result, the distance from the light emitting point on the light emitting surface of the LD element 10 to the mounting surface of the LD element 10 on the substrate 40 (the bottom surface of the recess in the light emitting device 200) can be increased by the thickness of the submount 50. The synchrotron radiation of the LD element can be efficiently applied to the light reflecting surface 21. The LD element 10 can be fixed to the submount 50 by using a conductive layer 60 such as Au-Sn.

As the submount 50, it is preferable to use one having a coefficient of thermal expansion between the coefficient of thermal expansion of the substrate 40 and the coefficient of thermal expansion of the LD element 10. As a result, it is possible to suppress the peeling of the LD element 10 and the peeling of the submount 50. When a material containing a nitride semiconductor is used as the LD element 10, for example, aluminum nitride or silicon carbide is used as the submount 50.

As shown in FIGS. 8 and 9, the LD element 10 is electrically connected to the wiring portion 42b of the substrate 40 by a wire (thin metal wire) 70.

(Light Reflector 20)
The light reflecting unit 20 reflects the synchrotron radiation from the LD element 10 toward the fluorescent unit 30. By reflecting the synchrotron radiation from the LD element 10 by the light reflecting unit 20 as in the light emitting device 200, the thickness of the light emitting device 200 (length in the vertical direction in FIG. 3) is compared with the case where a transmissive type lens is used. The intensity of the synchrotron radiation radiated to the light irradiation surface of the fluorescent unit 30 can be made evenly close to each other while reducing the size.

In FIG. 3, as the light reflecting unit 20, an optical element 20 having a light reflecting surface 21 on at least one surface is used. By separating the substrate 40 and the optical element 20, the substrate 40 can have a simple structure as compared with the case where a part of the substrate functions as a light reflecting surface. The substrate can also be configured so that a part of the substrate functions as a light reflecting surface. In this case, since it is not necessary to consider the region where the collet for arranging the optical element moves, the width of the concave portion of the substrate can be reduced.

In the present specification, all surfaces except the upper surface and the lower surface of the optical element 20 are side surfaces. In the light emitting device 200, as shown in FIGS. 3 and 4, one side surface of the four side surfaces of the optical element 20 on the side closer to the LD element 10 is the light reflecting surface 21. By forming the side surface closer to the LD element 10 as the light reflecting surface 21, the number of interfaces through which the synchrotron radiation passes can be reduced as compared with the case where the side surface farther from the LD element 10 is used as the light reflecting surface. , It is possible to suppress the absorption of light by the optical element.

As the optical element 20, a material whose main material is made of glass such as quartz or BK7 or a material resistant to heat such as metal such as aluminum and whose light reflecting surface 21 is made of a material having high reflectance such as metal may be used. can.

In the light emitting device 200, the light reflecting surface 21 is provided so that only the light intensity distribution in the longitudinal direction of the elliptical shape irradiated on the light irradiation surface approaches evenly. That is, the light reflecting surface 21 is provided so that only the light intensity distribution in the longitudinal direction approaches evenly without changing the light intensity distribution in the lateral direction. This is because the FFP of the LD element 10 tends to spread especially in the longitudinal direction. Although the light reflecting surface may be such that the light intensity distribution in the lateral direction approaches evenly, the light reflecting surface 21 may be formed in consideration of the accuracy of the light reflecting surface of the optical element and the alignment with the LD element. It is preferable that only the light intensity distribution in the longitudinal direction of the elliptical shape on the light irradiation surface is provided so as to approach evenly.

As shown in FIG. 4, the region on the light reflecting surface 21 where the synchrotron radiation is irradiated (the region surrounded by the alternate long and short dash line) is a region in which the elliptical FFP of the LD element 10 is divided into two or more in the longitudinal direction. Among them, it has a first region 21a corresponding to a region located at one end and a second region 21b corresponding to a region located at the other end. Then, as shown in FIG. 4, the first region 21a and the second region 21b are the synchrotron radiation reflected on the side of the radiated light reflected in the first region 21a near the second region 21b and the second region 21b. The radiated light reflected in the region 21b overlaps with the radiated light reflected on the side far from the first region 21a, and the radiated light reflected in the first region 21a on the far side from the second region 21b. The synchrotron radiation reflected in the second region 21b and the radiated light reflected on the side of the radiated light reflected in the second region 21b near the first region 21a are provided so as to overlap each other.

Here, the first region 21a and the second region 21b are the light intensity distribution of the synchrotron radiation reflected by the first region 21a and the synchrotron radiation reflected by the second region 21b on the light irradiation surface of the fluorescent unit 30, respectively. The light intensity distribution is provided so as to be line-symmetric with respect to the direction corresponding to the longitudinal direction. That is, on the light irradiation surface, the first region 21a and the second region 21b are provided so as to overlap each other with the same width. This makes it easier to bring the light intensity distribution on the light irradiation surface closer to uniform.

For example, as shown in FIG. 5, the area of the first region 21a located closer to the LD element 10 than the second region 21b is made smaller than the area of the second region 21b. Since the first region 21a located on the side closer to the LD element 10 has a longer distance to the light irradiation surface of the fluorescent unit 30 and the synchrotron radiation tends to spread, the first region 21a and the second region 21b are overlapped with the same width. It will be easier.

In the light emitting device 200, the region of the light reflecting surface 21 to be irradiated with the radiated light has a third region 21c located between the first region 21a and the second region 21b. As shown in FIG. 5, the third region 21c includes the radiated light reflected on the light irradiation surface of the fluorescent unit 30 on the side of the radiated light reflected by the third region 21c closer to the first region 21a. The radiated light reflected in the first region 21a overlaps with the radiated light reflected on the side far from the second region 21b, and at the same time, it overlaps with the second region 21b of the radiated light reflected in the third region 21c. The synchrotron radiation reflected on the near side and the radiated light reflected on the far side from the first region 21a of the radiated light reflected in the second region 21b are provided so as to overlap each other. That is, among the radiated light reflected in the third region 21c, the light having a low emission intensity (light reflected near the left end and the right end in the third region 21c in FIG. 5), the first region 21a, and the second region Of the radiated light reflected by 21b, the light having a high emission intensity (light reflected near the right end in the first region 21a of FIG. 5 and light reflected near the left end in the second region 21b) is superimposed. Can be done. When the light reflecting surface 21 has the third region 21c, the spread of the light reflected by the light reflecting surface 21 can be suppressed as compared with the case where the light reflecting surface 21 includes only the first region 21a and the second region 21b. Even if the distance from the light reflecting surface 21 to the light irradiation surface of the fluorescent unit 30 is increased, it is not necessary to lengthen the longitudinal direction of the light irradiation surface of the fluorescent unit 30. The region of the light reflecting surface 21 to which the synchrotron radiation is irradiated may include four or more regions.

In the first region 21a, the second region 21b, and the third region 21c, the emission angle of the synchrotron radiation reflected in the first region 21a and the second region 21b is reflected in the third region 21c in the longitudinal direction of the FFP. It is provided so as to be smaller than the emission angle of the synchrotron radiation. That is, in the longitudinal direction of the elliptical FFP, the light having high emission intensity in the third region 21c spreads outward, and the light in the side far from the third region 21c of the first region 21a and the second region 21b suppresses the spread. Is provided with a light reflecting surface 21. As a result, the light intensity distribution can be made uniform while suppressing the spread of the synchrotron radiation applied to the light irradiation surface.

As shown in FIG. 4, the first region 21a, the second region 21b, and the third region 21c are all planar. That is, the light reflecting surface 21 is composed of three planes. This facilitates the design of the optical element 20. The first region, the second region, and the third region may be curved surfaces, respectively.

FIG. 10 shows a diagram obtained by simulating and measuring the light intensity distribution of synchrotron radiation on the light irradiation surface of the fluorescent unit 30 of the light emitting device 200, and FIG. 11 shows a diagram showing the light intensity distribution in the straight line connecting XI and XI of FIG. Is shown. FIG. 12 shows a diagram obtained by simulating and measuring the light intensity distribution of the synchrotron radiation reflected in the first region 21a on the light irradiation surface of the fluorescent unit 30, and FIG. 13 shows the light intensity in the straight line connecting XIII-XIII in FIG. The figure showing the distribution is shown. FIG. 14 shows a diagram measured by simulating the light intensity distribution of the synchrotron radiation reflected in the second region 21b on the light irradiation surface of the fluorescent unit 30, and FIG. 15 shows the light intensity in the straight line connecting XV-XV of FIG. The figure showing the distribution is shown. FIG. 16 shows a diagram measured by simulating the light intensity distribution of the synchrotron radiation reflected in the third region 21c on the light irradiation surface of the fluorescent unit 30, and FIG. 17 shows the light intensity in the straight line connecting XVII-XVII of FIG. The figure showing the distribution is shown. Hereinafter, the simulation conditions will be described with reference to FIG. The distance from the light emitting point of the LD element 10 to the light reflecting surface (more accurately, the light reflecting point) of the light reflecting surface 21 in the direction parallel to the lower surface of the optical element 20 and the lower surface of the LD element 10 is 0.45 mm, and the optical element is set. The distance from the light reflection point of the light reflection surface 21 in the direction perpendicular to the lower surface of 20 to the light irradiation surface of the fluorescent unit 30 was set to 2.10 mm. At this time, a translucent portion 82 having a thickness of 0.5 mm and a radiator 100 having a thickness of 0.43 mm are arranged between the light reflection point and the fluorescent portion 30. The width of the light irradiation surface of the fluorescent unit 30 in the longitudinal direction (the length in the direction parallel to the straight direction from the light emitting point to the light reflection point) was 1 mm, and the lateral direction was 0.5 mm. Further, the angle between the lower surface of the optical element 20 and the first region 21a is 31.5 degrees, the angle between the lower surface of the optical element 20 and the second region 21b is 60 degrees, and the lower surface of the optical element 20 and the third region 21c. The angle between the optics was 45 degrees. At this time, the length L1 of the first region was 0.14 mm, the length L2 of the second region 21b was 0.36 mm, and the length L3 of the third region 21c was 0.27 mm. As shown in FIG. 11, according to the light emitting device 200, the light intensity distribution of the synchrotron radiation on the light irradiation surface of the fluorescent unit 30 can be made uniform.

(Cover 80)
The lid 80 is an airtightly sealed space in which the LD element 10 is arranged in combination with the substrate 40. As a result, it is possible to suppress the collection of organic substances and the like on the light emitting surface of the LD element 10. The lid 80 has a support portion 81, a translucent portion 82, and a bonding material 83 for joining the support portion 81 and the translucent portion 82. The light reflected by the light reflecting surface 21 passes through the translucent unit 82 and is applied to the light irradiation surface of the fluorescent unit 30.

Since the light emitting device 200 uses a material containing a nitride semiconductor as the LD element 10, the support portion 81 of the lid 80 and the substrate 40 are fixed by welding. In this case, a material containing iron as a main component can be used as the support portion 81. Further, in the light emitting device 200, the LD element 10 and the optical element 20 are arranged in one space airtightly sealed by the substrate 40 and the lid 80. As a result, it is possible to suppress the size of the light emitting device 200 from becoming larger than that of the light emitting device including the LD device on which the LD element is mounted and the optical element arranged outside the LD device. As the translucent portion 82, for example, glass or sapphire is used, and as the bonding material 83, for example, low melting point glass or gold-tin solder is used.

(Fluorescent unit 30)
The fluorescent unit 30 has a light irradiation surface on which the radiation reflected by the light reflection surface 21 is irradiated, and emits fluorescence when the light irradiation surface is irradiated with the radiation. In FIG. 3, the lower surface of the fluorescent unit 30 is the light irradiation surface, and the upper surface of the fluorescent unit 30 is the light extraction surface. As shown in FIG. 3, the fluorescent unit 30 is arranged above the translucent unit 82 in the lid 80.

The fluorescent unit 30 includes a phosphor. Examples of the fluorescent substance include a YAG fluorescent substance, a LAG fluorescent substance, and an α-sialon fluorescent substance. Above all, it is preferable to use a YAG phosphor having high heat resistance. The fluorescent unit 30 is preferably made of an inorganic material. As a result, the reliability can be improved because it is resistant to heat and light as compared with the case where an organic material is contained. As the fluorescent unit 30 made of an inorganic material, fluorescent ceramics or a single crystal of a fluorescent substance can be used. As the fluorescent ceramics, a sintered body of fluorescent particles and an additive can be used. When the fluorescent ceramics of the YAG phosphor are used, aluminum oxide can be used as an additive.

As shown in FIGS. 2 and 3, the light irradiation surface of the fluorescent unit 30 is preferably long in one direction. For example, it can be elliptical or rectangular, and is preferably rectangular from the viewpoint of mass productivity of the fluorescent unit 30. At this time, the radiated light reflected by the light reflecting surface 21 is irradiated in a long shape in one direction on the light irradiation surface of the fluorescent unit 30, and the fluorescent unit 30 and the semiconductor laser element 10 are radiated in the longitudinal direction of the fluorescent unit 30. It is preferable that the light is arranged so as to be parallel to the longitudinal direction of the light. As a result, the distance from the region exposed to the synchrotron radiation to the outer edge of the light irradiation surface on the light irradiation surface of the fluorescence unit 30 becomes small, so that the heat generated by the fluorescence unit 30 can be easily dissipated. Therefore, it becomes easy to reduce the decrease in the conversion efficiency of the fluorescent unit 30.

(First shading unit 90)
The first light-shielding portion 90 is for reducing the emission of light from a region other than the upper surface of the fluorescent portion 30, and is arranged on the side of the fluorescent portion 30 as shown in FIG. The first light-shielding portion 90 is provided in direct contact with the fluorescent portion 30. When the fluorescent unit 30 contains a YAG phosphor, it is preferable to use ceramics containing aluminum oxide as a main component as the first light-shielding unit 90. As a result, the light from the fluorescent unit 30 can be shielded while increasing the bonding force between the fluorescent unit 30 and the first light-shielding unit 90. The aluminum oxide used for the first light-shielding portion 90 is the same material as sapphire that can be used for the heat radiating body 100 described later, but the region of the first light-shielding portion 90 near the fluorescent portion 30 has a low sintering density. Therefore, there are voids in the area. Even if the same material is used, the light from the fluorescent unit 30 is reflected at the interface between particles such as aluminum oxide and the voids, so that the first light-shielding unit 90 is difficult to transmit light.

(Heat radiator 100)
As shown in FIG. 3, the fluorescent unit 30 and the first light-shielding unit 90 are fixed to the lid 80 via the heat radiating body 100. It is preferable that the upper surface of the heat radiating body 100 is in direct contact with the light irradiation surface of the fluorescent unit 30 and the lower surface of the first light-shielding unit 90. As a result, the region where heat is likely to be generated by the synchrotron radiation in the fluorescent unit 30 can be brought into direct contact with the radiator 100, so that the heat generated in the fluorescent unit 30 can be easily dissipated. As the heat radiating body 100, a translucent member can be used, and for example, sapphire, quartz or silicon carbide can be used. The fluorescent unit 30 may be arranged above the light reflecting surface by fixing the first light-shielding unit 90 and the heat-dissipating body 100 with a heat-resistant metal material or the like.

(Second shading unit 110)
A second light-shielding portion 110 is provided on the side surface of the heat radiating body 100. As a result, it is possible to prevent light from escaping from the side of the heat radiating body 100. As the second light-shielding portion 110, for example, a resin containing scattered particles such as titanium oxide is used.

<Second Embodiment>
FIG. 18 shows a cross-sectional view of the light emitting device 300 according to the second embodiment. The light emitting device 300 is substantially the same as the items described in the light emitting device 200 except for the items described below.

In the light emitting device 300, the light reflecting surface of the optical element 20 is provided on the side surface on the side far from the LD element 10. That is, the synchrotron radiation enters the inside of the optical element 20 from the side surface of the optical element 20 near the LD element 10, is reflected by the light reflecting surface 21, and is taken out from the upper surface of the optical element 20. Even in this case, the light intensity of the synchrotron radiation emitted on the light irradiation surface of the fluorescent unit 30 can be made uniform. At this time, as the optical element 20, an optical element 20 is used in which the main material is made of glass such as quartz or BK7 and the light reflecting surface is made of a material having high reflectance such as metal.

<Third Embodiment>
FIG. 19 shows a perspective view for explaining the inside of the recess of the substrate 40 in the light emitting device 400 according to the third embodiment, and FIG. 20 shows a top view of FIG. 19. The light emitting device 400 is substantially the same as the items described in the light emitting device 200 except for the items described below.

The light emitting device 400 includes two LD elements 10 and two optical elements 20. The optical element 20 is arranged so that the synchrotron radiation emitted from each LD element 10 is reflected by the light reflecting surface 21 of each optical element 20 and is irradiated on the light irradiation surface of one fluorescent unit 30. ing. Specifically, the two LD elements 10 are arranged so that their respective light emitting surfaces are parallel to each other, and the two optical elements 20 are arranged so that their opposite side surfaces are parallel to each other. The surface parallel to the side surface of the optical element 20 and the surface parallel to the light emitting surface of the LD element 10 are arranged so as to intersect at an angle other than vertical.

FIG. 21 shows a diagram obtained by simulating and measuring the light intensity distribution in the synchrotron radiation radiated to the light irradiation surface of the fluorescent unit 30 in the light emitting device 400. As shown in FIG. 21, the intensity of the synchrotron radiation radiated to the light irradiation surface of the fluorescent unit 30 can be increased by using the plurality of LD elements 10.

Also in this embodiment, the two opposite side surfaces of the recesses of the substrate may be used as light reflecting surfaces, and each of the two light reflecting surfaces may be irradiated with the synchrotron radiation from the LD element. Further, as the two optical elements, the optical elements used in the second embodiment can also be used.

<Fourth Embodiment>
FIG. 22 shows the synchrotron radiation from the light emitting device 500 according to the fourth embodiment until the synchrotron radiation emitted from the semiconductor laser element 10 is reflected by the light reflecting surface 21 and irradiated to the light irradiation surface of the phosphor 30. It is a figure for demonstrating the movement. The light emitting device 500 is substantially the same as the items described in the light emitting device 200 except for the items described below.

As shown in FIG. 22, in the light emitting device 500, the region irradiated with the synchrotron radiation on the light reflecting surface 21 corresponds to the region located at one end of the region in which the FFP on the elliptical shape is divided into three in the longitudinal direction. It has a first region 21a, a second region 21b corresponding to a region located at the other end, and a third region 21c located between the first region 21a and the second region 21b. At this time, in the first region 21a, the synchrotron radiation reflected in the first region 21a on the light irradiation surface of the fluorescent unit 30 is the first region 21a or the second of the synchrotron radiation reflected in the third region 21c. It is provided so as to overlap with the synchrotron radiation reflected on the side closer to one of the regions 21b. Further, in the second region 21b, on the light irradiation surface of the fluorescent unit 30, the synchrotron radiation reflected in the second region 21b is the first region 21a or the second region 21b of the synchrotron radiation reflected in the third region 21c. It is provided so as to overlap with the synchrotron radiation reflected on the side closer to the other side of the. That is, a part of the synchrotron radiation reflected in the first region 21a and a part of the synchrotron radiation reflected in the second region 21b in the region where the emission intensity of the synchrotron radiation reflected in the third region 21c is low. The first region 21a and the second region 21b are provided so that they overlap each other.

As shown in FIG. 22, in the light emitting device 500, in the first region 21a, the synchrotron radiation reflected in the first region 21a on the light irradiation surface of the fluorescent unit 30 is the synchrotron radiation reflected in the third region 21c. It is provided so as to overlap with the synchrotron radiation reflected on the side close to the second region 21b. Further, in the second region 21b, on the light irradiation surface of the fluorescent unit 30, the synchrotron radiation reflected by the second region 21b is on the side closer to the first region 21a of the synchrotron radiation reflected by the third region 21c. It is provided so as to overlap with the reflected synchrotron radiation. That is, the first region 21a and the second region 21a and the second region 21a and the second region 21a and the second region 21a and the second region so that the light irradiation surface of the fluorescent unit 30 is irradiated after the synchrotron radiation reflected in the first region 21a and the radiated light reflected in the second region 21b intersect. The region 21b is provided. As a result, of the light reflected in the first region 21a, the light having a low emission intensity (light reflected near the left end of the first region 21a in FIG. 22) and the light reflected in the third region 21c. Light with low emission intensity (light reflected near the right end of the third region 21c in FIG. 22) can be superimposed, and light with low emission intensity among the light reflected in the second region 21b (FIG. 22). (Light reflected near the right end of the second region 21b) and light of the light reflected in the third region 21c with lower emission intensity (light reflected near the left end of the third region 21c in FIG. 22). Can be stacked. Therefore, it is easy to make the light intensity of the synchrotron radiation on the light irradiation surface of the fluorescent unit 30 uniform.

In the light emitting device 500, the synchrotron radiation reflected in the first region and the radiated light reflected in the second region may not intersect. In other words, the light reflecting surface reflects the light reflected in the third region near the first region and the light reflected in the first region near the third region. The light reflected in the third region is superimposed, and the light reflected in the side of the light reflected in the third region near the second region and the light reflected in the second region are reflected in the side close to the third region. It may be provided so as to overlap with the emitted light. Even in this case, the light reflected in the first region and the light reflected in the second region can be overlapped with the light having a low emission intensity among the synchrotron radiation reflected in the third region. A certain effect can be obtained.

<Fifth Embodiment>
FIG. 23 shows the synchrotron radiation from the light emitting device 600 according to the fifth embodiment until the synchrotron radiation emitted from the semiconductor laser element 10 is reflected by the light reflecting surface 21 and irradiated to the light irradiation surface of the phosphor 30. It is a figure for demonstrating the movement. The light emitting device 600 is substantially the same as the items described in the light emitting device 200 except for the items described below.

In the light emitting device 600, the light reflecting surface 21 of the optical element 20 is a curved surface. At this time, the light reflecting surface 21 is the radiation reflected in the region corresponding to the region located at both ends in the longitudinal direction of the elliptical FFP so that the intensity distribution of the emitted light on the light irradiation surface of the fluorescent unit 30 approaches uniformly. The divergence angle of light is provided so as to be smaller than the divergence angle reflected in the region corresponding to the region located in the center in the longitudinal direction. That is, in the longitudinal direction of the elliptical FFP, the light reflecting surface 21 is provided so as to spread the light in the vicinity of the center to the outside and suppress the spreading of the light in the vicinity of both ends. Even in this case, the light intensity distribution of the synchrotron radiation on the light irradiation surface can be made uniform.

The light emitting device described in each embodiment can be used for lighting, vehicle lighting, and the like.

10 ... Semiconductor laser element 20 ... Light reflecting part 21 ... Light reflecting surface 21a ... First area 21b ... Second area 21c ... Third area 30 ... Fluorescent part 40 ... Base 41 ... Main body part 42a, 42b ... Wiring part 43 ... Welding Part 50 ... Submount 60 ... Conductive layer 70 ... Wire 80 ... Lid 81 ... Support part 82 ... Translucent part 83 ... Joining material 90 ... First light-shielding part 100 ... Dissipator 110 ... Second light-shielding part 200, 300, 400 , 500, 600 ... Light emitting device

In such a light emitting device, the light intensity of the synchrotron radiation radiated to the light irradiation surface of the fluorescent portion is higher in the central portion than in the surroundings. In this case, the calorific value of the fluorescent portion irradiated with the central portion of the synchrotron radiation increases, which may reduce the conversion efficiency of the fluorescent portion. In addition, there is a possibility that the emission intensity and color unevenness of the light extracted from the fluorescent portion may occur.
Alternatively, the light emitting device is preferably designed in consideration of heat dissipation.

The light emitting device according to one embodiment of the present invention comprises a semiconductor laser element, a light reflecting portion having a light reflecting surface, a recess in which the semiconductor laser element and the light reflecting portion are arranged, and the semiconductor laser element surrounding the recess. A substrate having an upper surface located above the light reflecting portion and a first wiring portion and a second wiring portion provided on the upper surface, and the semiconductor laser element emits light in the first direction. The light reflecting portion is arranged at a position separated from the semiconductor laser element in the first direction in the top view, and the first wiring portion and the second wiring portion are the first in the top view than the semiconductor laser element. It is a light emitting device that is arranged side by side in a second direction perpendicular to the first direction at a position separated in a direction opposite to one direction.

It can be a light emitting device in consideration of heat dissipation .

Claims (1)

A first semiconductor laser device whose synchrotron radiation has an elliptical furfield pattern,
A first light reflecting unit provided with a light reflecting surface that reflects the synchrotron radiation, and
It has a light irradiation surface to which the synchrotron radiation reflected by the light reflection surface is irradiated, and includes a fluorescent unit that emits fluorescence by irradiating the light irradiation surface with the radiant light.
The region on the light reflecting surface to be irradiated with the synchrotron radiation is a first region corresponding to a region located at one end of the region obtained by dividing the elliptical furfield pattern into two or more in the longitudinal direction, and the other end. Has a second region, which corresponds to the region located in
In the first region and the second region, the radiated light reflected at one end of the first region and the radiated light reflected at a position other than the other end of the light reflecting surface on the light irradiation surface of the fluorescent portion. The light is overlapped, and the radiated light reflected at the other end of the second region and the radiated light reflected at a position other than the one end on the light reflecting surface are provided so as to overlap each other. A characteristic light emitting device.

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