Light-emitting device

Abstract

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

Description

[Technical Field]

[0001] The present invention relates to a light emitting device. [Background technology]

[0002] 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 part disposed above the mirror member. The light emitted from the semiconductor laser element is reflected by a total reflection mirror provided on the mirror member to the fluorescent part (see, for example, FIG. 3 of Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2010-251686 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a light-emitting device, the intensity of the radiated light irradiated onto the light irradiation surface of the fluorescent unit is higher in the center than in the periphery. In this case, the amount of heat generated by the fluorescent unit irradiated by the center of the radiated light increases, which may reduce the conversion efficiency of the fluorescent unit. Furthermore, there is a risk of unevenness in the luminous intensity and color of the light extracted from the fluorescent unit. [Means for solving the problem]

[0005] A light emitting device according to one aspect of the present invention includes a base having 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 disposed, an upper surface surrounding the recess and positioned above the semiconductor laser element and the light reflecting portion, an in-recess wiring portion provided within the recess, and an outside-recess wiring portion provided outside the recess and electrically connecting to an external device, and a plurality of wires electrically connecting the semiconductor laser element to the in-recess wiring portion, wherein the number of semiconductor laser elements mounted in the recess is one, the semiconductor laser element emits light in a first direction, and the light reflecting portion is disposed at a position spaced apart from the semiconductor laser element in the first direction in a top view. when the recess is divided into two regions by a virtual straight line that passes between the semiconductor laser element and the light reflecting portion and is parallel to the second direction in top view, and the region that includes the semiconductor laser element is defined as a first region and the region that includes the light reflecting portion is defined as a second region, the plurality of wires are located within the first region, and the plurality of wires are joined to the wiring portion within the recess such that the junction points at which the wires are joined in the wiring portion within the recess are aligned in the first direction, and the base does not have an upper surface that is located above the light reflecting portion within the recess at a position away from the light reflecting portion in the first direction. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view of the light emitting device according to the first embodiment. [Figure 2] FIG. 2 is a top view of the light emitting device according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a perspective view of an optical element included in the light emitting device according to the first embodiment. [Figure 5] FIG. 5 is a diagram illustrating the movement of light emitted from the semiconductor laser element in the light emitting device according to the first embodiment, from the time when the light is reflected by the light reflecting surface until it is irradiated onto the light irradiating surface of the fluorescent section. [Figure 6]FIG. 6 is a diagram showing the light intensity distribution of the emitted light reflected by the conventional light reflecting surface, measured by simulation. [Figure 7] FIG. 7 is a diagram showing the light intensity distribution along the line connecting VII-VII in FIG. [Figure 8] FIG. 8 is a perspective view illustrating the inside of the recess of the base body in the light emitting device according to the first embodiment. [Figure 9] FIG. 9 is a top view illustrating the inside of the recess of the base in the light emitting device according to the first embodiment. [Figure 10] FIG. 10 is a diagram showing the light intensity distribution of the emitted light on the light irradiation surface of the fluorescent section in the light emitting device according to the first embodiment, measured through simulation. [Figure 11] FIG. 11 is a diagram showing the light intensity distribution along the line connecting XI-XI in FIG. [Figure 12] FIG. 12 is a diagram showing a simulated measurement of the light intensity distribution of emitted light reflected by the first region on the light irradiation surface of the fluorescent section in the light emitting device according to the first embodiment. [Figure 13] FIG. 13 is a diagram showing the light intensity distribution along the line connecting XIII-XIII in FIG. [Figure 14] FIG. 14 is a diagram showing a simulated measurement of the light intensity distribution of emitted light reflected by the second region on the light irradiation surface of the fluorescent section in the light emitting device according to the first embodiment. [Figure 15] FIG. 15 is a diagram showing the light intensity distribution along the line connecting XV-XV in FIG. [Figure 16] FIG. 16 is a diagram showing a simulation and measurement of the light intensity distribution of emitted light reflected by the third region on the light irradiation surface of the fluorescent section in the light emitting device according to the first embodiment. [Figure 17] FIG. 17 is a diagram showing the light intensity distribution along the line connecting XVII-XVII in FIG. [Figure 18] FIG. 18 is a cross-sectional view illustrating the light emitting device according to the second embodiment. [Figure 19]FIG. 19 is a perspective view illustrating the inside of the recess of the base in the light emitting device according to the third embodiment. [Figure 20] FIG. 20 is a top view illustrating the inside of the recess of the base in the light emitting device according to the third embodiment. [Figure 21] FIG. 21 is a diagram showing the light intensity distribution of the emitted light on the light irradiation surface of the fluorescent section in the light emitting device according to the third embodiment, measured through simulation. [Figure 22] FIG. 22 is a diagram illustrating the movement of light emitted from the semiconductor laser element in the light emitting device according to the fourth embodiment, from when the light is reflected by the light reflecting surface until it is irradiated onto the light irradiating surface of the fluorescent section. [Figure 23] FIG. 23 is a diagram illustrating the movement of light emitted from the semiconductor laser element in the light emitting device according to the fifth embodiment, from when the light is reflected by the light reflecting surface until it is irradiated onto the light irradiating surface of the fluorescent section. DETAILED DESCRIPTION OF THE INVENTION

[0007] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes embodiments of the present invention with reference to the accompanying drawings. However, the embodiments are intended to embody the technical concept of the present invention and are not intended to limit the scope of the present invention. The sizes and positional relationships of components shown in the drawings may be exaggerated for clarity.

[0008] First Embodiment Fig. 1 shows a perspective view of light-emitting device 200 according to the first embodiment, Fig. 2 shows a top view of light-emitting device 200, and Fig. 3 shows a cross-sectional view taken along line III-III in Fig. 2. Fig. 4 is a perspective view of optical element 20, which is light-reflecting section 20 in light-emitting device 200. Fig. 5 is a diagram illustrating the movement of emitted light in light-emitting device 200, from when it is emitted from semiconductor laser element 10 and reflected by light-reflecting surface 21 until it is irradiated onto the light-irradiation surface of fluorescent section 30.

[0009] 1 to 5, light emitting device 200 includes semiconductor laser element 10 having an elliptical far field pattern (hereinafter referred to as "FFP (Far Field Pattern)") of emitted light, light reflecting section 20 provided with light reflecting surface 21 that reflects the emitted light, and fluorescent section 30 having a light irradiation surface onto which the emitted light reflected by light reflecting surface 21 is irradiated and which emits fluorescence when the light irradiation surface is irradiated with the emitted light. In light emitting device 200, the region on light reflecting surface 21 onto which the emitted light is irradiated includes a first region 21a corresponding to a region located at one end of the elliptical FFP divided into two or more regions in the longitudinal direction, and a second region 21b corresponding to a region located at the other end. Furthermore, the first region 21a and the second region 21b are arranged such that, on the light irradiation surface of the fluorescent section 30, the radiated light reflected by the first region 21a on the side closer to the second region 21b overlaps with the radiated light reflected by the second region 21b on the side farther from the first region 21a, and the radiated light reflected by the first region 21a on the side farther from the second region 21b overlaps with the radiated light reflected by the second region 21b on the side closer to the first region 21a.

[0010] Light emitting device 200 can reduce unevenness in the emission intensity and color of light extracted from fluorescent section 30 while reducing the decrease in conversion efficiency of fluorescent section 30. This point will be described below.

[0011] The emitted light of a semiconductor laser element 10 (hereinafter referred to as "LD (Laser Diode) element 10") has an elliptical FFP in a plane parallel to the light emission surface of the LD element 10, in which the length in the stacking direction of multiple semiconductor layers including the active layer is longer than the length in the direction perpendicular to the stacking direction. The FFP here is a measurement of the light intensity distribution of the emitted light in a plane that is some distance from the light emission surface of the LD element 10 and parallel to the light emission surface, and is, for example, 1 / e from the peak intensity value. 2The shape of the ellipse is specified as the shape of the intensity when the intensity drops to an arbitrary value, such as 0.015 or 0.15. In this case, the intensity of the emitted light is higher at the center of the ellipse than at the portions farther from the center. In conventional light-emitting devices, for example, the emitted light from an LD element is reflected by a light-reflecting surface inclined at 45 degrees and irradiated onto the light-irradiation surface of the fluorescent unit. In this case, the light intensity distribution of the FFP is maintained while irradiating the light-irradiation surface of the fluorescent unit. This is also evident from the results of simulations and measurements of the light intensity distribution on the light-irradiation surface of a conventional light-emitting device, shown in Figures 6 and 7. Figure 7 shows the light intensity distribution along the line connecting VII-VII in Figure 6, where the light intensity at the center is clearly higher than that at the edges. When this light is irradiated onto the fluorescent unit, the heat generation amount of the fluorescent unit in the high-intensity region is greater than that of the surrounding area, resulting in a decrease in the conversion efficiency of the fluorescent unit. Furthermore, differences in the intensity of the emitted light irradiated onto the fluorescent unit may result in a light-emitting device with uneven light intensity and color.

[0012] Therefore, in the light emitting device 200, a first region 21a and a second region 21b are provided in the area on the light reflecting surface 21 where the radiated light is irradiated, 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 section 30. 5, the first region 21a and the second region 21b are arranged such that the radiation light reflected by the first region 21a has a low luminous intensity (the radiation light reflected near the left end of the first region 21a in FIG. 5) and the radiation light reflected by the second region 21b has a high luminous intensity (the radiation light reflected near the left end of the second region 21b in FIG. 5) overlap, and the radiation light reflected by the first region 21a has a high luminous intensity (the radiation light reflected near the right end of the first region 21a in FIG. 5) and the radiation light reflected by the second region 21b has a low luminous intensity (the radiation light reflected near the right end of the second region 21b in FIG. 5) overlap. This makes it possible to make the light intensity distribution of the radiation irradiated onto the light irradiation surface of the fluorescent unit 30 more uniform, thereby achieving a light emitting device with reduced unevenness in luminous intensity and color while minimizing the decrease in conversion efficiency of the fluorescent unit 30.

[0013] The components of the light emitting device 200 will be described below.

[0014] (Base 40) The base 40 is used to mount the LD element 10. In Fig. 3, the base 40 has a recess, and the LD element 10 is placed on the bottom surface of the recess.

[0015] The base 40 may be made of a material containing ceramics. Examples of ceramics include aluminum oxide, aluminum nitride, silicon nitride, and silicon carbide. When the base 40 and the lid 80 are fixed together by welding, the portion in contact with the lid 80 (weld portion 43) is made of a material containing iron as a main component.

[0016] 8 and 9, base 40 having a recessed portion has main body 41 made of an insulator, wiring portions 42a and 42b exposed from main body 41 on the top surface of base 40 and the bottom surface of the recessed portion, and welded portion 43 in contact with lid 80. By exposing wiring portion 42a, which is electrically connected to the outside, from a surface other than the bottom surface of main body 41, the entire bottom surface of base 40 can be used as a surface to be mounted on another member such as a heat sink, making it easier to dissipate heat generated by light emitting device 200 to the heat sink.

[0017] The substrate may include a base and a frame disposed on the upper surface of the base. In this case, the LD element is disposed on the upper surface of the base and inside the frame. In this case, it is preferable that the wiring portion is disposed on the upper surface of the base outside the frame, taking into consideration the heat dissipation of the light emitting device.

[0018] (Semiconductor laser element 10) The LD element 10 has an FFP from which light is emitted in an elliptical shape. The LD element 10 is arranged so that its light emission surface is perpendicular to the bottom surface of the base 40, and the longitudinal direction of the elliptical shape of the FFP is perpendicular to the bottom surface of the base 40. This allows the surface with the largest area of ​​the LD element 10 to be arranged parallel to the bottom surface of the base 40, making it easier to dissipate heat generated by the LD element 10 to the base 40 or a heat sink. Note that "perpendicular" here includes any tilt due to misalignment during mounting.

[0019] The LD element 10 may have an emission peak wavelength in the range of 320 nm to 530 nm, typically in the range of 430 nm to 480 nm. LD elements 10 in the aforementioned range emit relatively high-energy light, which tends to reduce the conversion efficiency of the phosphor section 30, and the effect of employing the light-reflecting surface 21 of this embodiment is significant. LD elements 10 in the aforementioned range are preferably made of a material containing a nitride semiconductor, such as GaN, InGaN, and at least one of AlGaN.

[0020] The LD element 10 is mounted on the base 40 via a submount 50. This allows the distance from the light emitting point on the light emitting surface of the LD element 10 to the mounting surface of the base 40 on which the LD element 10 is mounted (the bottom surface of the recess in the light emitting device 200) to be increased by the thickness of the submount 50, so that the emitted light from the LD element can be efficiently irradiated onto the light reflecting surface 21. The LD element 10 can be fixed to the submount 50 using a conductive layer 60 such as Au—Sn.

[0021] It is preferable to use a submount 50 having a thermal expansion coefficient between that of the base 40 and that of the LD element 10. This makes it possible to prevent peeling of the LD element 10 and the submount 50. When a material containing a nitride semiconductor is used for the LD element 10, the submount 50 is made of, for example, aluminum nitride or silicon carbide.

[0022] As shown in FIGS. 8 and 9, the LD element 10 is electrically connected to the wiring portion 42b of the base 40 by a wire (thin metal wire) 70.

[0023] (Light reflecting part 20) The light reflecting section 20 reflects the light emitted from the LD element 10 toward the fluorescent section 30. By reflecting the light emitted from the LD element 10 by the light reflecting section 20 as in the light emitting device 200, the thickness of the light emitting device 200 (the length in the vertical direction in FIG. 3 ) can be made smaller than when a transmissive lens is used, and the intensity of the light irradiated onto the light irradiation surface of the fluorescent section 30 can be made more uniform.

[0024] 3, an optical element 20 having a light-reflecting surface 21 on at least one surface is used as the light-reflecting portion 20. By making the base 40 and the optical element 20 separate, the base 40 can have a simpler configuration than when a portion of the base functions as the light-reflecting surface. The base can also be configured so that a portion of the base functions as the light-reflecting surface. In this case, there is no need to consider the area where the collet for positioning the optical element moves, and therefore the width of the recess in the base can be made smaller.

[0025] In this specification, all surfaces of the optical element 20 except for the top and bottom surfaces are referred to as side surfaces. In the light emitting device 200, as shown in Figures 3 and 4, one of the four side surfaces of the optical element 20 that is closer to the LD element 10 serves as a light reflecting surface 21. By using the side surface closer to the LD element 10 as the light reflecting surface 21, the number of interfaces through which the emitted light passes can be reduced compared to when the side surface farther from the LD element 10 is used as the light reflecting surface, and therefore light absorption in the optical element can be suppressed.

[0026] The optical element 20 may be mainly made of a heat-resistant material such as quartz or glass such as BK7, or a metal such as aluminum, and the light reflecting surface 21 may be made of a highly reflective material such as metal.

[0027] 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 onto the light irradiation surface becomes nearly uniform. In other words, the light reflecting surface 21 is provided so that only the light intensity distribution in the longitudinal direction becomes nearly uniform without changing the light intensity distribution in the lateral direction. This is because the FFP of the LD element 10 tends to spread particularly easily in the longitudinal direction. Note that it is also possible to provide a light reflecting surface that also becomes nearly uniform in the lateral direction, but considering the precision of the light reflecting surface of the optical element and the alignment with the LD element, it is preferable that the light reflecting surface 21 is provided so that only the light intensity distribution in the longitudinal direction of the elliptical shape on the light irradiation surface becomes nearly uniform.

[0028] 4, the region on the light reflecting surface 21 onto which the emitted light is irradiated (the region surrounded by the dashed line) includes a first region 21a corresponding to a region located at one end of the elliptical FFP of the LD element 10, which is divided into two or more regions in the longitudinal direction. The first region 21a and the second region 21b correspond to a region located at the other end of the elliptical FFP. As shown in FIG. 4, the first region 21a and the second region 21b are provided such that the emitted light reflected by the first region 21a on a side closer to the second region 21b overlaps with the emitted light reflected by the second region 21b on a side farther from the first region 21a, and the emitted light reflected by the first region 21a on a side farther from the second region 21b overlaps with the emitted light reflected by the second region 21b on a side closer to the first region 21a.

[0029] Here, the first region 21a and the second region 21b are provided so that the light intensity distribution of the radiated light reflected by the first region 21a and the light intensity distribution of the radiated light reflected by the second region 21b are line-symmetrical with respect to the direction corresponding to the longitudinal direction on the light irradiation surface of the fluorescent unit 30. In other words, the first region 21a and the second region 21b are provided so as to overlap with each other with the same width on the light irradiation surface. This makes it easier to make the light intensity distribution on the light irradiation surface closer to uniform.

[0030] 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. The first region 21a located closer to the LD element 10 has a longer distance to the light irradiation surface of the fluorescent section 30, which makes it easier for the emitted light to spread, making it easier for the first region 21a and the second region 21b to overlap with each other with the same width.

[0031] In the light-emitting device 200, the region of the light-reflecting surface 21 that is irradiated with the radiated light includes a third region 21c located between the first region 21a and the second region 21b. As shown in Fig. 5, the third region 21c is provided on the light-irradiated surface of the fluorescent section 30 so that the part of the radiated light reflected by the third region 21c that is closer to the first region 21a overlaps with the part of the radiated light reflected by the first region 21a that is farther from the second region 21b, and so that the part of the radiated light reflected by the third region 21c that is closer to the second region 21b overlaps with the part of the radiated light reflected by the second region 21b that is farther from the first region 21a. In other words, light with a low luminous intensity among the radiated light reflected by the third region 21c (light reflected near the left and right ends of the third region 21c in FIG. 5 ) can be superimposed on light with a high luminous intensity among the radiated light reflected by the first region 21a and the second region 21b (light reflected near the right end of the first region 21a and light reflected near the left end of the second region 21b in FIG. 5 ). 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 compared to when the light reflecting surface 21 is composed of only the first region 21a and the second region 21b. Therefore, 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. Note that the region on the light reflecting surface 21 onto which the radiated light is irradiated may include four or more regions.

[0032] The first region 21a, the second region 21b, and the third region 21c are provided so that the divergence angle of the radiated light reflected by the first region 21a and the second region 21b in the longitudinal direction of the FFP is smaller than the divergence angle of the radiated light reflected by the third region 21c. In other words, the light reflecting surface 21 is provided so that, in the longitudinal direction of the elliptical FFP, the light with high emission intensity from the third region 21c spreads outward, and the light on the sides of the first region 21a and the second region 21b farther from the third region 21c is suppressed from spreading. This makes it possible to make the light intensity distribution closer to uniform while suppressing the spread of the radiated light irradiated onto the light irradiation surface.

[0033] 4, the first region 21a, the second region 21b, and the third region 21c are all flat surfaces. That is, the light reflecting surface 21 is composed of three flat surfaces. This facilitates the design of the optical element 20. Note that the first region, the second region, and the third region may each be a curved surface.

[0034] FIG. 10 shows a simulated measurement of the light intensity distribution of radiated light on the light-irradiated surface of the fluorescent section 30 of the light-emitting device 200, and FIG. 11 shows a diagram illustrating the light intensity distribution along the line connecting XI-XI in FIG. 10. FIG. 12 shows a simulated measurement of the light intensity distribution of radiated light reflected by the first region 21a on the light-irradiated surface of the fluorescent section 30, and FIG. 13 shows a diagram illustrating the light intensity distribution along the line connecting XIII-XIII in FIG. 12. FIG. 14 shows a simulated measurement of the light intensity distribution of radiated light reflected by the second region 21b on the light-irradiated surface of the fluorescent section 30, and FIG. 15 shows a diagram illustrating the light intensity distribution along the line connecting XV-XV in FIG. 14. FIG. 16 shows a simulated measurement of the light intensity distribution of radiated light reflected by the third region 21c on the light-irradiated surface of the fluorescent section 30, and FIG. 17 shows a diagram illustrating the light intensity distribution along the line connecting XVII-XVII in FIG. 16. The simulation conditions are described below with reference to FIG. 5. The distance from the light-emitting point of LD element 10 to the light-reflecting surface (more precisely, the light-reflecting point) of light-reflecting surface 21 in a direction parallel to the lower surface of optical element 20 and the lower surface of LD element 10 was 0.45 mm, and the distance from the light-reflecting point of light-reflecting surface 21 to the light-irradiated surface of fluorescent section 30 in a direction perpendicular to the lower surface of optical element 20 was 2.10 mm. In this case, a light-transmitting section 82 having a thickness of 0.5 mm and a heat sink 100 having a thickness of 0.43 mm were disposed between the light-reflecting point and fluorescent section 30. The width of the light-irradiated surface of fluorescent section 30 in the longitudinal direction (the length in the direction parallel to the straight direction from the light-emitting point to the light-reflecting point) was 1 mm, and the width in the lateral direction was 0.5 mm. Furthermore, the angle between the lower surface of optical element 20 and first region 21a was set to 31.5 degrees, the angle between the lower surface of optical element 20 and second region 21b was set to 60 degrees, and the angle between the lower surface of optical element 20 and third region 21c was set to 45 degrees. In this case, the length L1 of first region 21a was set to 0.14 mm, the length L2 of second region 21b was set to 0.36 mm, and the length L3 of third region 21c was set to 0.27 mm. As shown in Fig. 11, light-emitting device 200 can make the light intensity distribution of emitted light on the light-irradiated surface of fluorescent section 30 closer to uniform.

[0035] (lid 80) The lid 80, in combination with the base 40, forms an airtightly sealed space in which the LD element 10 is placed. This makes it possible to suppress the collection of organic matter and other particles on the light-emitting surface of the LD element 10. The lid 80 has a support portion 81, a light-transmitting portion 82, and a bonding material 83 that bonds the support portion 81 and the light-transmitting portion 82. Light reflected by the light-reflecting surface 21 passes through the light-transmitting portion 82 and is irradiated onto the light-irradiating surface of the fluorescent unit 30.

[0036] In the light-emitting device 200, the LD element 10 is made of a material containing a nitride semiconductor, and therefore the support portion 81 of the lid 80 is fixed to the base 40 by welding. In this case, a material containing iron as a main component can be used for the support portion 81. In addition, in the light-emitting device 200, the LD element 10 and the optical element 20 are arranged in a single space hermetically sealed by the base 40 and the lid 80. This makes it possible to prevent the light-emitting device 200 from becoming larger than a light-emitting device including an LD device equipped with an LD element and an optical element arranged outside the LD device. The light-transmitting portion 82 is made of, for example, glass or sapphire, and the bonding material 83 is made of, for example, low-melting-point glass or gold-tin solder.

[0037] (Fluorescent part 30) Fluorescent unit 30 has a light irradiation surface onto which the radiated light reflected by light reflecting surface 21 is irradiated, and emits fluorescence when the radiated light is irradiated onto the light irradiation surface. In Fig. 3 , the lower surface of fluorescent unit 30 is the light irradiation surface, and the upper surface of fluorescent unit 30 is the light extraction surface. As shown in Fig. 3 , fluorescent unit 30 is disposed above light-transmitting unit 82 of lid 80.

[0038] The fluorescent section 30 includes a phosphor. Examples of phosphors include YAG phosphor, LAG phosphor, and α-sialon phosphor. Among these, it is preferable to use a YAG phosphor, which has high heat resistance. The fluorescent section 30 is preferably made of an inorganic material. This makes it more resistant to heat and light than a phosphor containing an organic material, thereby improving reliability. As the fluorescent section 30 made of an inorganic material, phosphor ceramics or a phosphor single crystal can be used. As the phosphor ceramics, a sintered body of phosphor particles and an additive can be used. When using phosphor ceramics of a YAG phosphor, aluminum oxide can be used as the additive.

[0039] 2 and 3, the light irradiation surface of the fluorescent unit 30 is preferably elongated in one direction. For example, it may be elliptical or rectangular, and a rectangular shape is preferable from the viewpoint of mass production of the fluorescent unit 30. In this case, the emitted light reflected by the light reflecting surface 21 is irradiated onto the light irradiation surface of the fluorescent unit 30 in a shape elongated in one direction, and the fluorescent unit 30 and the semiconductor laser element 10 are preferably arranged so that the longitudinal direction of the fluorescent unit 30 and the longitudinal direction of the emitted light are parallel to each other. This reduces the distance from the region of the light irradiation surface of the fluorescent unit 30 where the emitted light strikes to the outer edge of the light irradiation surface, making it easier to dissipate heat generated in the fluorescent unit 30. This makes it easier to reduce a decrease in the conversion efficiency of the fluorescent unit 30.

[0040] (First light-shielding portion 90) The first light-shielding portion 90 is intended to reduce light from emitting from regions other than the top surface of the fluorescent portion 30 and is disposed to the side of the fluorescent portion 30, as shown in FIG. 3 . The first light-shielding portion 90 is provided in direct contact with the fluorescent portion 30. When the fluorescent portion 30 contains a YAG phosphor, it is preferable to use ceramics containing aluminum oxide as a main component for the first light-shielding portion 90. This allows for increased bonding strength between the fluorescent portion 30 and the first light-shielding portion 90 while blocking light from the fluorescent portion 30. The aluminum oxide used for the first light-shielding portion 90 is the same material as sapphire, which can be used for the heat sink 100 described below. However, the sintered density of the region of the first light-shielding portion 90 closest to the fluorescent portion 30 is low, resulting in the presence of voids in that region. Even though the first light-shielding portion 90 is made of the same material, light from the fluorescent portion 30 is reflected at the interface between particles such as aluminum oxide and the voids, making it difficult for light to pass through the first light-shielding portion 90.

[0041] (heat sink 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 sink 100. It is preferable that the upper surface of the heat sink 100 be in direct contact with the light-irradiated surface of the fluorescent unit 30 and the lower surface of the first light-shielding unit 90. This allows the heat sink 100 to be in direct contact with an area of ​​the fluorescent unit 30 that is likely to generate heat when hit by radiated light, making it easier to dissipate heat generated in the fluorescent unit 30. A light-transmitting member such as sapphire, quartz, or silicon carbide can be used as the heat sink 100. Note that the fluorescent unit 30 may be positioned above the light-reflecting surface by fixing the first light-shielding unit 90 and the heat sink 100 together using a heat-resistant metal material or the like.

[0042] (Second light-shielding part 110) A second light-shielding portion 110 is provided on the side surface of the heat dissipation body 100. This makes it possible to prevent light from escaping from the side of the heat dissipation body 100. The second light-shielding portion 110 is made of, for example, a resin containing scattering particles such as titanium oxide.

[0043] Second Embodiment 18 shows a cross-sectional view of a light emitting device 300 according to the second embodiment. The light emitting device 300 is substantially the same as the light emitting device 200 except for the following points.

[0044] In the light emitting device 300, the light reflecting surface of the optical element 20 is provided on the side surface farther from the LD element 10. In other words, the emitted light enters the inside of the optical element 20 from the side surface of the optical element 20 closer to the LD element 10, is reflected by the light reflecting surface 21, and is extracted from the upper surface of the optical element 20. Even in this case, the light intensity of the emitted light irradiated on the light irradiation surface of the fluorescent unit 30 can be made nearly uniform. In this case, the optical element 20 used is made mainly of glass such as quartz or BK7, and the light reflecting surface is made of a highly reflective material such as metal.

[0045] <Third embodiment> Fig. 19 is a perspective view illustrating the inside of the recess of the base 40 in a light-emitting device 400 according to the third embodiment, and Fig. 20 is a top view of Fig. 19. The light-emitting device 400 is substantially the same as the light-emitting device 200 except for the matters described below.

[0046] The light emitting device 400 includes two LD elements 10 and two optical elements 20. The optical elements 20 are arranged so that the light emitted from each LD element 10 is reflected by the light reflecting surface 21 of each optical element 20 and is irradiated onto the light irradiation surface of one fluorescent section 30. Specifically, the two LD elements 10 are arranged so that their light emitting surfaces are parallel, and the two optical elements 20 are arranged so that their opposing side surfaces are parallel. The optical elements 20 are arranged so that a plane parallel to the side surface of each optical element 20 and a plane parallel to the light emitting surface of each LD element 10 intersect at an angle other than perpendicular.

[0047] 21 shows a diagram obtained by simulating and measuring the light intensity distribution of the radiated light irradiated onto the light irradiation surface of the fluorescent section 30 in the light emitting device 400. As shown in Fig. 21, by using a plurality of LD elements 10, the intensity of the radiated light irradiated onto the light irradiation surface of the fluorescent section 30 can be increased.

[0048] In this embodiment, too, two opposing side surfaces of the recess of the base may be light-reflecting surfaces, and the light emitted from the LD element may be irradiated onto each of the two light-reflecting surfaces. Also, the optical elements used in the second embodiment may be used as the two optical elements.

[0049] <Fourth embodiment> 22 is a diagram illustrating the movement of radiated light from semiconductor laser element 10 in light-emitting device 500 according to the fourth embodiment, from when the radiated light is reflected by light-reflecting surface 21 until it is irradiated onto the light-irradiation surface of fluorescent section 30. Light-emitting device 500 is substantially the same as the light-emitting device 200, except for the matters described below.

[0050] 22 , in the light-emitting device 500, the region on the light-reflecting surface 21 onto which the radiated light is irradiated includes a first region 21a corresponding to the region located at one end of the elliptical FFP divided into three regions in the longitudinal direction, a second region 21b corresponding to the region located at the other end, and a third region 21c located between the first region 21a and the second region 21b. The first region 21a is provided on the light-irradiated surface of the fluorescent unit 30 such that the radiated light reflected by the first region 21a overlaps with the radiated light reflected by the third region 21c on the side closer to either the first region 21a or the second region 21b. The second region 21b is provided on the light-irradiated surface of the fluorescent unit 30 such that the radiated light reflected by the second region 21b overlaps with the radiated light reflected by the third region 21c on the side closer to the other of the first region 21a or the second region 21b. In other words, the first region 21a and the second region 21b are arranged so that a portion of the radiated light reflected by the first region 21a and a portion of the radiated light reflected by the second region 21b overlap with a region of low luminous intensity of the radiated light reflected by the third region 21c.

[0051] 22 , in the light-emitting device 500, the first region 21a is provided such that the radiated light reflected by the first region 21a overlaps with the radiated light reflected by the third region 21c on a side closer to the second region 21b on the light irradiation surface of the fluorescent unit 30. Furthermore, the second region 21b is provided such that the radiated light reflected by the second region 21b overlaps with the radiated light reflected by the third region 21c on a side closer to the first region 21a on the light irradiation surface of the fluorescent unit 30. In other words, the first region 21a and the second region 21b are provided such that the radiated light reflected by the first region 21a and the radiated light reflected by the second region 21b intersect with each other before being irradiated onto the light irradiation surface of the fluorescent unit 30. This allows the light reflected by the first region 21a to have a low luminous intensity (light reflected near the left end of the first region 21a in FIG. 22) to overlap with the light reflected by the third region 21c to have a low luminous intensity (light reflected near the right end of the third region 21c in FIG. 22), and also allows the light reflected by the second region 21b to have a low luminous intensity (light reflected near the right end of the second region 21b in FIG. 22) to overlap with the light reflected by the third region 21c to have a low luminous intensity (light reflected near the left end of the third region 21c in FIG. 22). This makes it easier to make the intensity of the radiated light on the light irradiation surface of the fluorescent unit 30 more uniform.

[0052] In the light-emitting device 500, the radiated light reflected by the first region and the radiated light reflected by the second region may not intersect. In other words, the light reflecting surface may be provided so that the light reflected by the third region on the side closer to the first region overlaps the light reflected by the first region on the side closer to the third region, and the light reflected by the third region on the side closer to the second region overlaps the radiated light reflected by the second region on the side closer to the third region. Even in this case, a certain effect can be obtained because the light with low luminous intensity reflected by the third region can overlap the light reflected by the first region and the light reflected by the second region.

[0053] Fifth Embodiment 23 is a diagram illustrating the movement of radiated light from the semiconductor laser element 10 in the light-emitting device 600 according to the fifth embodiment, from when the radiated light is reflected by the light-reflecting surface 21 until it is irradiated onto the light-irradiating surface of the fluorescent section 30. The light-emitting device 600 is substantially the same as the light-emitting device 200, except for the matters described below.

[0054] In the light-emitting device 600, the light-reflecting surface 21 of the optical element 20 is a curved surface. In this case, the light-reflecting surface 21 is provided so that the divergence angle of the radiated light reflected from areas corresponding to the areas located at both ends in the longitudinal direction of the elliptical FFP is smaller than the divergence angle of the radiated light reflected from an area corresponding to the area located at the center in the longitudinal direction, so that the intensity distribution of the radiated light on the light-irradiation surface of the fluorescent section 30 becomes more uniform. In other words, the light-reflecting surface 21 is provided so that, in the longitudinal direction of the elliptical FFP, the light near the center spreads outward and the light near both ends is suppressed from spreading. Even in this case, the light intensity distribution of the radiated light on the light-irradiation surface can be made more uniform. [Industrial Applicability]

[0055] The light emitting device described in each embodiment can be used for illumination, vehicle lighting, and the like. [Explanation of symbols]

[0056] 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 42a, 42b...Wiring section 43...Welded section 50...Submount 60...Conductive layer 70...Wire 80...lid body 81...Support part 82…Translucent part 83...Joining material 90...First light-shielding part 100...Heat sink 110...Second light-shielding part 200, 300, 400, 500, 600...light-emitting devices

Claims

1. a semiconductor laser element; a light reflecting portion having a light reflecting surface; a base having a recess in which the semiconductor laser element and the light reflecting portion are disposed, an upper surface which is a plane surrounding the recess and is located above the semiconductor laser element and the light reflecting portion, an in-recess wiring portion provided within the recess, and an outside-recess wiring portion provided outside the recess and electrically connected to the outside; a plurality of wires electrically connecting the semiconductor laser element to the wiring portion within the recess; Equipped with the number of semiconductor laser elements mounted in the recess is one, the semiconductor laser element emits light in a first direction; the light reflecting portion is disposed at a position spaced apart from the semiconductor laser element in a first direction in a top view, the recess is divided into two regions, a first region including the semiconductor laser element and the plurality of wires, and a second region including the light reflecting portion, by an imaginary line that passes between the semiconductor laser element and the light reflecting portion and is parallel to a second direction that is perpendicular to the first direction, in a top view; a plurality of wires are joined to the recessed wiring portion such that a plurality of junction points, which are points at which the wires are joined to the recessed wiring portion, are arranged in the first direction; the base does not have an upper surface located above the light reflecting portion within the recess at a position away from the light reflecting portion in the first direction.

2. the recess wiring portion includes a first wiring portion and a second wiring portion, the plurality of wires include a plurality of first wires joined to the first wiring portion and a plurality of second wires joined to the second wiring portion; the plurality of first wires are joined to the first wiring portion at positions that are farther apart in the second direction than the semiconductor laser element in a top view, The light emitting device according to claim 1 , wherein the plurality of second wires are joined to the second wiring portion at positions spaced apart from the semiconductor laser element in a direction opposite to the second direction in a top view.

3. the first wires are joined to the first wiring portion such that a plurality of first junction points are arranged in the first direction, the first junction points being the junction points to which the first wires are joined in the first wiring portion; the second wires are joined to the second wiring portion such that a plurality of second junction points are arranged in the first direction, the second junction points being the junction points to which the second wires are joined in the second wiring portion; The light emitting device of claim 2 , wherein the plurality of first junction points and the plurality of second junction points are located within the first region.

4. the base does not have an upper surface located above the light reflecting portion in the recess at a position away from the light reflecting portion in the second direction, 4. The light-emitting device according to claim 1, wherein the base does not have an upper surface located above the light-reflecting portion within the recess at a position away from the light-reflecting portion in a direction opposite to the second direction.

5. The light emitting device according to claim 1 , wherein the outer wiring portion is not provided on the lower surface of the base outside the recess.

6. The light emitting device according to claim 1 , wherein the outside-recess wiring portion is not provided outside the recess at a position where the imaginary straight line passes in a top view.

7. the wiring portion outside the recess portion includes a third wiring portion and a fourth wiring portion, the third wiring portion and the fourth wiring portion are provided on the upper surface, 7. The light-emitting device according to claim 1, wherein the third wiring portion and the fourth wiring portion are arranged side by side in a second direction perpendicular to the first direction, at a position farther away from the semiconductor laser element in a direction opposite to the first direction when viewed from above.

8. a submount on which the semiconductor laser element is disposed, the plurality of first wires are bonded to the semiconductor laser element; The light emitting device according to claim 1 (excluding a light emitting device not citing claim 2), wherein the plurality of second wires are bonded to the submount.

9. The light emitting device according to claim 8 , wherein the first wire is longer than the second wire when viewed from above.

10. The light emitting device according to claim 8 , wherein the number of the plurality of first wires is greater than the number of the plurality of second wires.

11. The light emitting device according to claim 1 , wherein the substrate is composed of a base portion on which the semiconductor laser element is disposed, and a frame portion disposed on the base portion.

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