Light emitting device

Abstract

Provided is a light-emitting device that emits light having a good polarization ratio. The light-emitting device includes: a first sub-substrate having a ceramic substrate containing AlN and a plurality of upper metal layers provided on an upper surface side of the ceramic substrate; and a first semiconductor laser element that is disposed on the upper surface of the first sub-substrate and oscillates in a TM mode, the plurality of upper metal layers including one or more upper first metal layers having a metal layer containing at least Ni.

Description

Technical Field

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

[0002] Patent Document 1 discloses a sub-substrate in which a main conductor layer composed of Au, Ag, Cu or Al is formed on an insulating substrate composed of an aluminum nitride sintered body, a silicon carbide sintered body, diamond, silicon, an alumina sintered body, a glass ceramic sintered body, a silicon nitride sintered body, quartz, sapphire or a cubic boron nitride ceramic, a barrier layer composed of Pt, Pd, Rh, Ru, Ni, a Ni-Cr alloy or a Ti-W alloy is formed thereon, an Au-Sn alloy layer is formed thereon, and a Ni layer is further formed thereon. In addition, Patent Document 1 states that the possibility of positional deviation of optical semiconductor elements can be reduced by using such a sub-substrate.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: (Japanese) Patent Publication No. 2008-34581 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] In a light emitting device having a semiconductor laser element, the polarization ratio of the light (laser) emitted from the light emitting device is sometimes required to be greater than a specified value. In a light emitting device, when a semiconductor laser element is arranged on a sub-substrate, the material used and the way the sub-substrate is constructed will affect the polarization ratio of the light emitted from the semiconductor laser element.

[0008] Technical solutions for solving technical problems

[0009] The light-emitting device disclosed in the embodiment comprises: a first sub-substrate, which has a ceramic substrate containing AlN and a plurality of upper metal layers arranged on the upper surface side of the ceramic substrate; a first semiconductor laser element, which is arranged on the upper surface of the first sub-substrate and oscillates in a TM mode, and the plurality of upper metal layers include one or more upper first metal layers, and the upper first metal layer has a metal layer containing at least Ni.

[0010] In at least one of the one or more inventions disclosed in the embodiments, a light emitting device that emits light with a good polarization ratio is realized. Alternatively, in at least one of the one or more inventions disclosed in the embodiments, a light emitting device that emits red light with a polarization ratio of 100 or more is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a perspective view of a light emitting device according to an embodiment.

[0012] Figure 2 It is a top view of the light emitting device according to the embodiment.

[0013] Figure 3 This is a perspective view showing a state before optical components are mounted on the light emitting device according to the embodiment.

[0014] Figure 4 yes Figure 3 A top view of the state.

[0015] Figure 5 It is a perspective view for explaining each component arranged inside the light emitting device according to the embodiment.

[0016] Figure 6 yes Figure 5 A top view of the state.

[0017] Figure 7 is from Figure 6 A top view of the state after the wiring is removed.

[0018] Figure 8 yes Figure 7 A cross-sectional view taken along section line VIII-VIII.

[0019] Fig. 9 yes Figure 7 A cross-sectional view taken along section line IX-IX.

[0020] Fig. 10A is a cross-sectional view of a sub-substrate according to an embodiment.

[0021] Fig. 10B This is a cross-sectional view of a sub-substrate having a structure different from that of the sub-substrate in the embodiment.

[0022] Fig. 10C This is a cross-sectional view showing a state where a semiconductor laser element is arranged on a sub-substrate according to an embodiment.

[0023] Fig. 10D This is a cross-sectional view showing a state where a semiconductor laser element is arranged on a sub-substrate according to an embodiment.

[0024] Fig.11 This is a schematic diagram of an experimental environment in an experiment for measuring a polarization ratio performed in a state where a semiconductor laser element is arranged on a sub-substrate. DETAILED DESCRIPTION

[0025] In this specification or claims, polygons such as triangles and quadrilaterals are also referred to as polygons, including shapes where the corners of the polygons are processed by rounding, chamfering, corner chamfering, rounding, etc. In addition, shapes where the middle part of the side is processed are also referred to as polygons, not limited to corners (ends of the sides). That is, shapes where the polygon is retained on the base and local processing is performed are included in the interpretation of "polygon" recorded in this specification and claims.

[0026] In addition, it is not limited to polygons. The same applies to words that represent specific shapes such as trapezoids, circles, and concave-convex shapes. In addition, the same applies to the processing of the sides that form the shape. In other words, even if processing is performed on the diagonal or middle part of a side, the processed part is also included in the interpretation of "side". It should be noted that in the case of distinguishing "polygons" or "sides" without local processing from the processed shape, "strict" is marked, for example, it is recorded as "strict quadrilateral" etc.

[0027] In addition, in this specification or claims, the records of up and down (above / below), left and right, front and back, front and back (front / back), near and inside are merely descriptions of relative positions, orientations, directions, etc., and may not be consistent with the relationships during use.

[0028] In addition, in the drawings, arrows are sometimes used to indicate directions such as the X direction, the Y direction, and the Z direction. The directions of the arrows are matched between multiple drawings of the same embodiment. In addition, in the drawings, the directions of the arrows marked with X, Y, and Z are set as positive directions, and the directions opposite thereto are set as negative directions. For example, the direction marked with X in front of the arrow is the X direction, and is the positive direction. It should be noted that the direction that is the X direction and is the positive direction is referred to as the "positive direction of X", and the direction opposite thereto is referred to as the "negative direction of X". The same applies to the Y direction and the Z direction.

[0029] In addition, in this specification, for example, when describing a constituent element, it is described as a "component" or a "section". A "component" refers to an object that is physically handled as a single unit. An object that is physically handled as a single unit can also be said to be an object that is handled as a single component in a manufacturing process. On the other hand, a "section" refers to an object that may not be handled physically as a single unit. For example, a "section" is used when partially capturing a part of a component or when capturing multiple components as a single object.

[0030] It should be noted that the above-mentioned division between "components" and "parts" does not mean that the scope of rights is intentionally limited in the interpretation of the doctrine of equivalents. That is, even if there is a component recorded as a "component" in the claims, the applicant will not recognize that physically treating the component as a single body is indispensable for the application of the present invention based on this alone.

[0031] In addition, in this specification or claims, when there are multiple components, in the case of distinguishing the components, sometimes the head of the component is marked with "first" or "second" to distinguish them. In addition, the objects distinguished in this specification and the claims may be different. Therefore, even if the claims record the same components as those marked in this specification, the objects determined by the components may be inconsistent between this specification and the claims.

[0032] For example, in this specification, there are constituent elements marked with "first", "second", and "third" to distinguish them. When the constituent elements marked with "first" and "third" in this specification are recorded in the claims, there is a case where the constituent elements are marked with "first" and "second" in the claims to distinguish them from the viewpoint of easy observation. In this case, the constituent elements marked with "first" and "second" in the claims refer to the constituent elements marked with "first" and "third" in this specification, respectively. It should be noted that the applicable objects of this rule are not limited to constituent elements, and it is also reasonably and flexibly applicable to other objects.

[0033] The following describes a method for implementing the present invention. In addition, a specific method for implementing the present invention is described with reference to the accompanying drawings. It should be noted that the method for implementing the present invention is not limited to the specific method. That is, the illustrated embodiment is not the only method for implementing the present invention. It should be noted that the size, positional relationship, etc. of the components shown in the drawings are sometimes exaggerated for ease of understanding.

[0034] <Implementation Method>

[0035] A light emitting device 1 according to an embodiment will be described. Figures 1 to 9 It is a diagram for explaining an exemplary embodiment of the light emitting device 1 . Figure 1 It is a perspective view of the light emitting device 1 . Figure 2 is a top view of the light emitting device 1 . Figure 3 It is a perspective view showing a state before the optical component 80 is mounted on the light emitting device 1 . Figure 4 yes Figure 3 A top view of the state. Figure 5 It is a perspective view for explaining each component arranged inside the light emitting device 1 . Figure 6 yes Figure 5 A top view of the state. Figure 7 is from Figure 6 The state in which the wiring 60 is removed is a top view. Figure 8 yes Figure 7 A cross-sectional view taken along section line VIII-VIII. Fig. 9 yes Figure 7 A cross-sectional view taken along section line IX-IX. Fig. 10Ais a schematic cross-sectional view of the sub-substrate 30 . Fig. 10B 1 is a schematic cross-sectional view of the sub-substrate 99 . Fig. 10C and Fig. 10D It is a schematic cross-sectional view showing a state where the semiconductor laser element 20 is arranged on the sub-substrate 30 .

[0036] The light emitting device 1 includes a plurality of components including a package 10 , one or more semiconductor laser elements 20 , one or more sub-substrates 30 , one or more reflective members 40 , one or more protective elements 50 , a plurality of wirings 60 , and an optical member 80 .

[0037] It should be noted that the light emitting device 1 may also include other components. For example, the light emitting device 1 may include a light emitting diode or a semiconductor laser element in addition to one or more semiconductor laser elements 20. In addition, the light emitting device 1 may not include some of the multiple components listed here.

[0038] First, each component will be described.

[0039] (Package 10)

[0040] The package 10 has a base 14, a frame 15, and a cover 17. The package 10, for example, includes a base member constituting the base 14 and the frame 15, and a cover member constituting the cover 17. It should be noted that the base member may also be formed by joining a mounting member constituting the base 14 and a frame member constituting the frame 15. Alternatively, the package 10 may also include a base member constituting the base 14, and a cover member constituting the frame 15 and the cover 17.

[0041] The package 10 has a mounting surface 11D on which other components are arranged. The package 10 has a closed space formed therein. The mounting surface 11D is provided in the closed space. The internal space (the closed space formed inside) is a sealed space. In addition, the internal space is a space sealed in an airtight state under a predetermined ambient gas.

[0042] The package 10 has an uppermost surface 11A, a lowermost surface 11B, and a mounting surface 11D. The base 14 has the mounting surface 11D. In addition, the cover 17 has an uppermost surface 11A, and the base 14 has a lowermost surface 11B. The frame 15 surrounds the mounting surface 11D when viewed from above. When viewed from above, the outer edge shape of the package 10 is rectangular. It should be noted that the outer edge shape of the package 10 may not be rectangular.

[0043] The base member has one or more step portions 12C. The step portion 12C has an upper surface and an inner side surface intersecting with the upper surface and extending downward from the upper surface. The upper surface of the step portion 12C is located above the mounting surface 11D.

[0044] One or more wiring patterns are provided on the upper surface of the step portion 12C. The wiring pattern is electrically connected to other wiring patterns of the frame portion 15 via wiring passing through the inside of the frame portion 15. For example, the wiring pattern provided on the upper surface of the step portion 12C is electrically connected to the wiring pattern provided on the lower surface of the frame portion 15.

[0045] For example, the main material of the mounting component is metal or a composite containing metal. For example, copper can be cited as the main material of the mounting component. In addition, for example, the main material of the frame component is ceramic. For example, aluminum nitride, silicon nitride or aluminum oxide can be cited as the main material of the frame component. The main material of the cover component is, for example, any one of quartz, silicon carbide, sapphire or glass. It should be noted that the main material of the mounting component can also be ceramic. For example, in the case where the base 14 and the frame 15 are formed integrally using the same material, the main material of the base component can be ceramic.

[0046] Here, the main material refers to the material that accounts for the largest proportion by weight or volume in the object to be formed. It should be noted that when the object to be formed is formed by one material, the material is the main material. That is, a certain material is the main material, including the proportion of the material accounted for 100%.

[0047] (Semiconductor Laser Element 20)

[0048] The semiconductor laser element 20 has a light emitting surface for emitting light. The semiconductor laser element 20 has an upper surface, a lower surface, and a plurality of side surfaces. The side surfaces of the semiconductor laser element 20 serve as light emitting surfaces. The shape of the upper surface of the semiconductor laser element 20 is a rectangle having long sides and short sides. It should be noted that the shape of the upper surface of the semiconductor laser element 20 may not be a rectangle.

[0049] The semiconductor laser element 20 may be a single-emitter semiconductor laser element. Alternatively, the semiconductor laser element 20 may be a multi-electrode semiconductor laser element having a plurality of emitters. For example, the semiconductor laser element 20 may be a semiconductor laser element having two emitters.

[0050] The semiconductor laser element 20 can be, for example, a semiconductor laser element that emits red light. Alternatively, the semiconductor laser element 20 can be a semiconductor laser element that emits green light. Alternatively, the semiconductor laser element 20 can be a semiconductor laser element that emits blue light. Alternatively, the semiconductor laser element 20 can also be a semiconductor laser element that emits light of other colors.

[0051] Here, blue light refers to light whose emission peak wavelength is within the range of 420nm to 494nm. Green light refers to light whose emission peak wavelength is within the range of 495nm to 570nm. Red light refers to light whose emission peak wavelength is within the range of 605nm to 750nm.

[0052] The light (laser light) emitted from the semiconductor laser element 20 has a spread. In addition, the light emitted from the emission end face (light emission face) of the semiconductor laser element 20 is a divergent light.

[0053] Light emitted from the semiconductor laser element 20 forms an elliptical far field pattern (hereinafter referred to as "FFP") on a plane parallel to the light emission end face. FFP refers to the shape and light intensity distribution of emitted light at a position far from the emission end face.

[0054] Here, light passing through the center of the elliptical shape of the FFP, in other words, light with peak intensity in the light intensity distribution of the FFP, is referred to as light advancing along the optical axis or light passing through the optical axis. 2 Light with an intensity above this is called main light.

[0055] The shape of the FFP of the light emitted from the semiconductor laser element 20 is an elliptical shape in which the stacking direction is longer than the direction perpendicular to the stacking direction in a plane parallel to the light emission end face. The stacking direction refers to the direction in which a plurality of semiconductor layers including an active layer are stacked in the semiconductor laser element 20. The direction perpendicular to the stacking direction can also be referred to as the surface direction of the semiconductor layer. In addition, the long-axis direction of the elliptical shape of the FFP can also be referred to as the fast-axis direction of the semiconductor laser element 20, and the short-axis direction can be referred to as the slow-axis direction of the semiconductor laser element 20.

[0056] Based on the light intensity distribution of FFP, 1 / e of the peak light intensity 2 The angle at which the light intensity of the light spreads is defined as the light spread angle of the semiconductor laser element 20. The light spread angle is equal to 1 / e of the peak light intensity. 2 In addition to the light intensity of the peak light intensity, it can also be obtained from the light intensity of the half value of the peak light intensity. In the description of this specification, when it is simply referred to as "the spread angle of light", it means 1 / e of the peak light intensity. 2 It should be noted that the spreading angle of light in the fast axis direction can be said to be larger than the spreading angle of the slow axis direction.

[0057] The semiconductor laser element 20 may be a semiconductor laser element including an active layer made of a GaAs-based material. Alternatively, the semiconductor laser element 20 may be a semiconductor laser element including an active layer made of a GaN-based material.

[0058] For example, as a semiconductor laser element 20 emitting blue light or a semiconductor laser element 20 emitting green light, a semiconductor laser element including an active layer composed of a GaN-based material can be cited. As GaN-based materials, for example, GaN, InGaN, and AlGaN can be cited. As a semiconductor laser element 20 emitting red light, a semiconductor laser element including an active layer composed of a semiconductor of a GaP-based or GaAs-based material can be cited. As GaAs-based materials, for example, GaAs and AlGaAs can be cited. As GaP-based materials, GaP, AlGaP, and AlGaInP can be cited. The active layer can also be composed of a semiconductor containing As and P, such as GaAsP.

[0059] (Sub-board 30)

[0060] The sub-substrate 30 has an upper surface and a lower surface. The thickness of the sub-substrate 30 is greater than 170 μm and less than 500 μm. The sub-substrate 30 has a ceramic substrate 31 and a plurality of metal layers 32. The ceramic substrate 31 has an upper surface and a lower surface. The plurality of metal layers 32 include a plurality of upper metal layers 33A disposed on the upper surface side of the sub-substrate 30. In addition, the plurality of metal layers 32 may include a plurality of lower metal layers 33B disposed on the lower surface side of the sub-substrate 30. The plurality of metal layers 32 may constitute the upper surface and the lower surface of the sub-substrate 30.

[0061] The ceramic substrate 31 includes aluminum nitride (AlN). The main material of the ceramic substrate 31 is aluminum nitride. Aluminum nitride can be said to be a material with relatively excellent heat dissipation among ceramic materials. By using this material, a sub-substrate 30 with good heat dissipation can be manufactured. The thickness of the ceramic substrate 31 is not less than 150 μm and not more than 300 μm.

[0062] The plurality of upper metal layers 33A include one or more upper first metal layers 34A, and the upper first metal layer 34A includes a metal layer containing at least Ni. In addition, the one or more upper first metal layers 34A may include a metal layer containing Au.

[0063] The thickness of the Ni-containing metal layer in one or more upper first metal layers 34A is greater than 1 μm and less than 5 μm. The thickness of one or more upper first metal layers 34A is greater than 1.01 μm and less than 5.1 μm. It should be noted that the thickness of the metal layer 32 refers to the thickness in the direction perpendicular to the surface in contact with the metal layer 32.

[0064] The plurality of upper metal layers 33A include an upper second metal layer 35A disposed between the ceramic substrate 31 and one or more upper first metal layers 34A. The upper second metal layer 35A is a metal layer containing Cu. In addition, the main material of the upper second metal layer 35A is Cu. It should be noted that the upper second metal layer 35A may also be made of a metal other than Cu having excellent heat dissipation properties.

[0065] The thickness of the upper second metal layer 35A is greater than the thickness of one or more upper first metal layers 34A. The thickness of the upper second metal layer 35A is greater than or equal to 100 μm and less than or equal to 100 μm. The upper second metal layer 35A is the thickest upper metal layer 33A.

[0066] The plurality of upper metal layers 33A include one or more upper third metal layers 36A on the upper surface side of the ceramic substrate 31 . The upper third metal layer 36A includes a metal layer 32 containing at least Pt provided on the upper surface side of one or more upper first metal layers 34A.

[0067] One or more upper third metal layers 36A may further include a metal layer containing Ti. One or more upper third metal layers 36A may further include a metal layer containing Au. One or more upper third metal layers 36A may include two metal layers containing Pt, and the two metal layers are provided with a metal layer containing a metal other than Pt sandwiched therebetween. The thickness of one or more upper third metal layers 36A is greater than or equal to 0.5 μm and less than or equal to 1.5 μm.

[0068] The plurality of upper metal layers 33A include an uppermost metal layer 37A disposed at the top of the plurality of upper metal layers 33A. The uppermost metal layer 37A is a metal layer containing Au or a metal layer containing an AuSn alloy. The thickness of the uppermost metal layer 37A is greater than or equal to 0.01 μm and less than or equal to 5 μm. The uppermost metal layer 37A can constitute the upper surface of the sub-substrate 30.

[0069] In relation to the top metal layer 37A, one or more top first metal layers 34A can be said to be intermediate metal layers provided between the ceramic substrate 31 and the top metal layer 37A. Similarly, in relation to the top metal layer 37A, the top second metal layer 35A and the top third metal layer 36A can be said to be intermediate metal layers provided between the ceramic substrate 31 and the top metal layer 37A.

[0070] The plurality of upper metal layers 33A include a lowermost metal layer 38A disposed at the bottom of the plurality of upper metal layers 33A. The lowermost metal layer 38A may be a metal layer containing TiW, a metal layer containing Cu, or a metal layer containing Ni. The thickness of the lowermost metal layer 38A is not less than 0.05 μm and not more than 0.15 μm.

[0071] The plurality of lower metal layers 33B include one or more lower first metal layers 34B, wherein the lower first metal layer 34B has a metal layer containing at least Ni. In addition, one or more lower first metal layers 34B may include a metal layer containing Au. The thickness of the metal layer containing Ni in the one or more lower first metal layers 34B is greater than 1 μm and less than 5 μm. The thickness of the one or more lower first metal layers 34B is greater than 1.01 μm and less than 5.1 μm.

[0072] The plurality of lower metal layers 33B include a lower second metal layer 35B provided between the ceramic substrate 31 and one or more lower first metal layers 34B. The lower second metal layer 35B is a metal layer containing Cu. In addition, the main material of the lower second metal layer 35B is Cu. In addition, the lower second metal layer 35B may also be made of a metal other than Cu having excellent heat dissipation properties.

[0073] The thickness of the lower second metal layer 35B is greater than the thickness of one or more lower first metal layers 34B. The thickness of the lower second metal layer 35B is greater than or equal to 100 μm and less than or equal to 100 μm. The lower second metal layer 35B is the thickest lower metal layer 33B.

[0074] The plurality of lower metal layers 33B do not include the metal layer 32 containing at least Pt provided on the lower surface of one or more lower first metal layers 34B on the lower surface of the ceramic substrate 31. The metal layer 32 containing at least Pt is not provided on the lower surface of the ceramic substrate 31.

[0075] The plurality of lower metal layers 33B include a lowermost metal layer 37B located at the bottom of the plurality of lower metal layers 33B. The lowermost metal layer 37B is a metal layer containing Au or a metal layer containing an AuSn alloy. The thickness of the lowermost metal layer 37B is greater than or equal to 0.1 μm and less than or equal to 7 μm. The lowermost metal layer 37B can constitute the lower surface of the sub-substrate 30.

[0076] In relation to the lowermost metal layer 37B, one or more lower first metal layers 34B can be said to be an intermediate metal layer provided between the ceramic substrate 31 and the lowermost metal layer 37B. Similarly, in relation to the lowermost metal layer 37B, the lower second metal layer 35B can be said to be an intermediate metal layer provided between the ceramic substrate 31 and the lowermost metal layer 37B.

[0077] The plurality of lower metal layers 33B include an uppermost metal layer 38B disposed at the top of the plurality of lower metal layers 33B. The uppermost metal layer 38B can be any one of a metal layer containing TiW, a metal layer containing Cu, or a metal layer containing Ni. The thickness of the uppermost metal layer 38B is not less than 0.05 μm and not more than 0.15 μm.

[0078] (Reflection member 40)

[0079] The reflecting member 40 has a light reflecting surface for reflecting light. In addition, the light reflecting surface is inclined relative to the lower surface. That is, the configuration relationship of the light reflecting surface observed from the lower surface is neither vertical nor parallel. The straight line connecting the lower end and the upper end of the light reflecting surface is inclined relative to the lower surface of the reflecting member 40. The angle of the light reflecting surface relative to the lower surface, or the angle of the straight line connecting the lower end and the upper end of the light reflecting surface relative to the lower surface is referred to as the inclination angle of the light reflecting surface.

[0080] In the illustrated reflective member 40, the light reflecting surface is a plane and is inclined at a 45 degree angle relative to the lower surface of the reflective member 40. In addition, the light reflecting surface may not be a plane, for example, it may be a curved surface. In addition, the light reflecting surface may not have an inclined angle of 45 degrees.

[0081] The reflective member 40 can be made of glass, metal, etc. as the main material. The main material can be a heat-resistant material, for example, glass such as quartz or BK7 (borosilicate glass), or metal such as aluminum. The reflective member 40 can also be formed using Si as the main material. If the main material is a reflective material, the light reflecting surface can be formed by the main material. In the case where the light reflecting surface is formed separately from the main material, the light reflecting surface can be made of metal such as Ag, Al, or Ta. 2 O 5 / SiO 2 、TiO 2 / SiO 2 , Nb 2 O 5 / SiO 2 It is formed by dielectric multilayer films.

[0082] In the light reflecting surface, the reflectivity of the light irradiated to the light reflecting surface relative to the peak wavelength is 90% or more. Alternatively, the reflectivity may be 95% or more. Alternatively, the reflectivity may be 99% or more. The light reflectivity is 100% or less.

[0083] (Protection element 50)

[0084] The protection element 50 is used to prevent an excessive current from flowing through a specific element (for example, the semiconductor laser element 20) and being destroyed. As the protection element 50, for example, a Zener diode can be cited. In addition, as the Zener diode, a Zener diode formed of Si can be used.

[0085] (Wiring 60)

[0086] The wiring 60 is a linear conductive material with both ends as a junction. The junctions at both ends serve as a junction with other components. The wiring 60 is, for example, a metal wire. For example, gold, aluminum, silver, copper, etc. can be used as the metal.

[0087] (Optical component 80)

[0088] The optical component 80 has an upper surface, a lower surface, and side surfaces, and provides incident light with optical effects such as reflection, transmission, and refraction, or optical effects such as condensation, diffusion, and collimation.

[0089] The optical component 80 may have one or more lens surfaces. One or more lens surfaces are disposed on the upper surface side of the optical component 80. It should be noted that it may also be disposed on the lower surface side of the optical component 80. The upper surface and the lower surface are planes. One or more lens surfaces intersect with the upper surface. One or more lens surfaces are surrounded by the upper surface when viewed from above. When viewed from above, the optical component 80 has a rectangular shape. The lower surface of the optical component 80 is rectangular.

[0090] The portion of the optical component 80 that overlaps with one or more lens surfaces when viewed from above is set as a lens portion. In the optical component 80, the portion that overlaps with the upper surface when viewed from above is set as a non-lens portion. The lens surface side when the lens portion is divided into two by an imaginary plane including the upper surface is set as a lens shape portion, and the lower surface side is set as a flat plate shape portion. The lower surface of the lens portion is a part of the lower surface. In the optical component 80, the lower surface is composed of the lower surface of the lens portion and the lower surface of the non-lens portion.

[0091] The optical component 80 shown in the figure has a plurality of lens surfaces. In addition, the plurality of lens surfaces are formed in a continuous manner in one direction. The optical component 80 has four lens surfaces, and is formed in such a way that the vertices of the four lens surfaces are arranged on a straight line.

[0092] Here, the direction in which the plurality of lens surfaces are arranged in a plan view is referred to as a connecting direction. In a plan view, the length of the plurality of lens surfaces in the connecting direction is greater than the length in a direction perpendicular to the direction. In the illustrated optical component 80, the connecting direction is the same direction as the X direction.

[0093] The optical component 80 has high light transmittance. The optical component 80 has high light transmittance in both the lens portion and the non-lens portion. In addition, the optical component 80 has high light transmittance as a whole. The optical component 80 can be formed using glass such as BK7, for example.

[0094] (Light-emitting device 1)

[0095] Next, the light emitting device 1 including the above-mentioned components will be described.

[0096] In the light emitting device 1, one or more semiconductor laser elements 20 are arranged on the mounting surface 11D. One or more semiconductor laser elements 20 are arranged in a manner that their light emitting surfaces face the side. One or more semiconductor laser elements 20 are arranged in a manner that their light emitting surfaces face the same direction. It should be noted that the same direction here includes the situation where the rotational offset of the light emitting surfaces of adjacent semiconductor laser elements 20 on the plane parallel to the mounting surface 11D is within the range of ±5 degrees. In the illustrated light emitting device 1, a plurality of semiconductor laser elements 20 are arranged in an X direction.

[0097] In the light emitting device 1, one or more sub-substrates 30 are arranged on the mounting surface 11D. One or more semiconductor laser elements 20 are arranged on the upper surfaces of the one or more sub-substrates 30. The one or more semiconductor laser elements 20 include semiconductor laser elements 20 arranged on the mounting surface 11D via the sub-substrates 30.

[0098] One or more semiconductor laser elements 20 may be disposed on one sub-mount 30. In the light emitting device 1 shown in the figure, the number of semiconductor laser elements 20 disposed on one sub-mount 30 is one.

[0099] One or more semiconductor laser elements 20 include a semiconductor laser element 20 that is disposed on the submount 30 and oscillates in the TM mode. This allows the polarization ratio of light emitted from the semiconductor laser element 20 disposed on the submount 30 to be a good value. This point will be described in more detail.

[0100] Fig. 10B It is a cross-sectional view showing the structure of sub-substrate 99 used in the comparative experiment with sub-substrate 30. Sub-substrate 99 is different from sub-substrate 30 in that it does not have a Ni-containing metal layer in the upper metal layer. That is, sub-substrate 99 does not have a structure equivalent to one or more upper first metal layers 34A in sub-substrate 30. In addition, sub-substrate 99 is different from sub-substrate 30 in that a Pt-containing metal layer is provided in the lower metal layer instead of the Ni-containing metal layer. Whereas sub-substrate 30 uses a Ni / Au metal layer as one or more lower first metal layers 34B, sub-substrate 99 uses a Ti / Pt / Au metal layer as one or more lower first metal layers. It should be noted that in Fig. 10B For convenience, the portion corresponding to the sub-substrate 30 is marked with Fig. 10A The sub-substrate 30 has the same reference numerals as the sub-substrate 30 .

[0101] Tables 1 to 4 show the results of polarization ratio measurement experiments performed using the sub-substrate 30 and the sub-substrate 99. Fig.11Schematic diagram of the experimental conditions when the experimental data of Tables 1 to 4 were obtained. When the semiconductor laser element 20 was arranged on the sub-substrate 30 or the sub-substrate 99, the light emitted from the semiconductor laser element 20 was passed through the collimating lens E1 and measured as collimated light. In addition, in the measurement of the polarization ratio, as the polarizer E2, a Glan laser calcite polarizer manufactured by Thorlabs was used, as the ND filter E3, a metal film ND filter manufactured by Melles Griot Co., Ltd. was used, and as the detector photodiode E4, a detector photodiode manufactured by Hamamatsu Photonics of Japan was used.

[0102] In addition, in the sub-substrate 30 used in the experiment, the ceramic substrate 31 is a ceramic substrate with AlN as the main material, one or more upper first metal layers 34A and one or more lower first metal layers 34B are both 2.5μm Ni metal layers and 0.02μm Au metal layers, the upper second metal layer 35A and the lower second metal layer 35B are both Cu metal layers, one or more upper third metal layers 36A are 0.56μm Ti / Pt / Au metal layers and 0.3μm Pt metal layers, the uppermost metal layer 37A of the upper metal layer 33A is a 0.05μm Au metal layer arranged on the 2.5μm AuSn metal layer, the lowermost metal layer 37B of the lower metal layer 33B is a 5μm AuSn metal layer, and the lowermost metal layer 38A of the upper metal layer 33A and the uppermost metal layer 38B of the lower metal layer 33B are 0.1μm TiW metal layers.

[0103] In addition, in the sub-substrate 99 used for the experiment, the ceramic substrate is a ceramic substrate with AlN as the main material, one or more lower first metal layers 34B are 0.06μm Ti metal layer, 0.2μm Pt metal layer and 0.3μm Au metal layer, the upper second metal layer and the lower second metal layer are both Cu metal layers, one or more upper third metal layers are 0.56μm Ti / Pt / Au metal layer and 0.3μm Pt metal layer, the uppermost metal layer of the upper metal layer is a 0.05μm Au metal layer arranged on a 2.5μm AuSn metal layer, the lowermost metal layer of the lower metal layer is a 5μm AuSn metal layer, and the lowermost metal layer of the upper metal layer and the uppermost metal layer of the lower metal layer are 0.1μm TiW metal layer.

[0104] Table 1 shows the results of measuring the polarization ratio (TE / TM) of the semiconductor laser element disposed on the sub-substrate 99 and the semiconductor laser element disposed on the sub-substrate 30 while making the thickness of the ceramic substrate, the upper second metal layer, and the lower second metal layer, which are the main thicknesses of the sub-substrate, the same. It should be noted that any semiconductor laser element used is a semiconductor laser element that oscillates in the TM mode and is manufactured in the same manufacturing process.

[0105] [Table 1]

[0106] Subbase 99 Sub-base 30 Thickness of ceramic substrate [μm] 150 150 Thickness of the upper second metal layer (Cu layer) [μm] 75 75 Thickness of the upper second metal layer (Cu layer) [μm] 75 75 Polarization ratio 74.5 169.9

[0107] Thus, according to the experimental results in Table 1, if the thickness of the sub-substrate is set to be roughly the same to compare the sub-substrate 99 and the sub-substrate 30, the value of the polarization ratio of the sub-substrate 30 is higher. According to this result, it is speculated that the Ni metal layer 32 and the Au metal layer 32 in the upper first metal layer 34A of the sub-substrate 30 affect the difference in the value of the polarization ratio. In addition, if the upper metal layer in the sub-substrate 99 also includes an Au metal layer, it is speculated that the Ni metal layer 32 has a greater impact on the difference in the value of the polarization ratio.

[0108] Table 2 shows the results of measuring the polarization ratio of the semiconductor laser element disposed on the sub-substrate 30 by making the thickness of the ceramic substrate 31 equal, changing the thickness of the upper second metal layer and the lower second metal layer in the sub-substrate 30. It should be noted that any semiconductor laser element used is a semiconductor laser element oscillating in the TM mode and manufactured in the same manufacturing process.

[0109] [Table 2]

[0110] Sub-base 30 Sub-base 30 Sub-base 30 Sub-base 30 Thickness of ceramic substrate [μm] 150 150 150 150 Thickness of the upper second metal layer (Cu layer) [μm] 15 25 35 75 Thickness of the lower second metal layer (Cu layer) [μm] 15 25 35 75 Polarization ratio 178.6 184.3 168.3 177.4

[0111] Thus, it can be seen from the experimental results in Table 2 that even if the thickness of the upper second metal layer and the lower second metal layer in the sub-substrate is changed, no significant difference is found in the value of the polarization ratio. Based on this result, it is inferred that the thickness of the upper second metal layer 35A and the lower second metal layer 35B of the sub-substrate 30 hardly affects the difference in the value of the polarization ratio.

[0112] Table 3 shows the results of measuring the polarization ratio of the semiconductor laser element disposed on the sub-substrate 99 by making the thickness of the sub-substrate equal and changing the thickness of the ceramic substrate. It should be noted that any semiconductor laser element used is a semiconductor laser element oscillating in the TM mode and manufactured in the same manufacturing process.

[0113] [Table 3]

[0114] Subbase 99 Subbase 99 Subbase 99 Thickness of ceramic substrate [μm] 150 200 250 Thickness of the upper second metal layer (Cu layer) [μm] 75 50 25 Thickness of the lower second metal layer (Cu layer) [μm] 75 50 25 Polarization ratio 54.5 58.0 74.6

[0115] Thus, according to the experimental results in Table 3, no significant difference in the polarization ratio value was found between the sub-substrate 99 having a ceramic substrate thickness of 150 μm and the sub-substrate 99 having a ceramic substrate thickness of 200 μm. On the other hand, it can be seen that the polarization ratio value of the sub-substrate 99 having a ceramic substrate thickness of 250 μm is higher than the polarization ratio value of the sub-substrate 99 having a ceramic substrate thickness of 150 μm or 200 μm. Based on this result, it is inferred that in the sub-substrate 30, by making the thickness of the ceramic substrate 31 to be of a certain size, the polarization ratio value can also be relatively improved.

[0116] However, it can be seen from comparison between Table 1 and Table 3 that the change in the value of the polarization ratio caused by the thickness of the ceramic substrate is smaller than the change in the value of the polarization ratio caused by the difference between the sub-substrate 30 and the sub-substrate 99 in the experiment of Table 1. Among the sub-substrates 30, the ceramic substrate 31 has a greater influence on the thickness of the sub-substrate 30. If the thickness of the ceramic substrate changes, the thickness of the sub-substrate 30 changes, which sometimes has a greater influence on the design of the installation position of other components of the light-emitting device 1, etc. Therefore, it is also necessary to consider such influence to determine the thickness of the ceramic substrate 31.

[0117] Table 4 shows the results of configuring a semiconductor laser element oscillating in TM mode and a semiconductor laser element oscillating in TE mode in the same sub-substrate 30 and measuring the value of the polarization ratio, and configuring a semiconductor laser element oscillating in TM mode and a semiconductor laser element oscillating in TE mode in the same sub-substrate 99 and measuring the value of the polarization ratio. It should be noted that the semiconductor laser elements oscillating in TM mode are all semiconductor laser elements manufactured in the same manufacturing process, and the semiconductor laser elements oscillating in TE mode are all semiconductor laser elements manufactured in the same manufacturing process. In addition, the semiconductor laser elements oscillating in TM mode and the semiconductor laser elements oscillating in TE mode are both semiconductor laser elements that emit red light. Specifically, the peak wavelength of the light emission of the semiconductor laser element oscillating in TM mode is in the range of more than 638nm and less than 642nm, and the peak wavelength of the light emission of the semiconductor laser element oscillating in TE mode is in the range of more than 638nm and less than 642nm. In addition, the number of emitters of the semiconductor laser element oscillating in TM mode is two, and the number of emitters of the semiconductor laser element oscillating in TE mode is one.

[0118] [Table 4]

[0119]

[0120] Thus, according to the experimental results of Table 4, in the semiconductor laser element oscillating in the TE mode, although no significant change was found in the value of the polarization ratio when the sub-substrate 99 was replaced by the sub-substrate 30, in the semiconductor laser element oscillating in the TM mode, if the sub-substrate 99 was replaced by the sub-substrate 30, an improvement was found in the value of the polarization ratio.

[0121] As shown in the experimental results, by changing from sub-substrate 99 to sub-substrate 30, the polarization ratio of light emitted from the TM mode semiconductor laser element becomes a relatively good value, but it is speculated whether this is affected by the change in the tensile strain of sub-substrate 99 and sub-substrate 30 due to the presence of a Ni-containing metal layer.

[0122] The sub-substrate 99 and the sub-substrate 30 used in the experiment have a rectangular shape with a long side of 1.6 mm and a short side of 1.2 mm when viewed from above. In addition, the semiconductor laser element 20 oscillating in the TM mode arranged on these sub-substrates has a rectangular shape with a long side of 1.5 mm and a short side of 0.4 mm when viewed from above. If the warping amount in the long side direction and the warping amount in the short side direction of the semiconductor laser element 20 arranged on the sub-substrate 99 and the sub-substrate 30 are measured, the warping amount in the long side direction of the semiconductor laser element 20 arranged on the sub-substrate 30 is relatively greater than the warping amount in the long side direction of the semiconductor laser element 20 arranged on the sub-substrate 99. Specifically, the warping amount in the long side direction of the sub-substrate 30 was found to be in the range of 0.4μm to 0.9μm, and the warping amount in the long side direction of the sub-substrate 99 was found to be in the range of 0.2μm to 0.6μm. In addition, the warping amount in the short side direction of the semiconductor laser element 20 arranged on the sub-substrate 30 is relatively smaller than the warping amount in the short side direction of the semiconductor laser element 20 arranged on the sub-substrate 99. Specifically, the warping amount in the short side direction of the sub-substrate 30 is found to be in the range of 0.01 μm to 0.03 μm, and the warping amount in the short side direction of the sub-substrate 99 is found to be in the range of 0.03 μm to 0.05 μm.

[0123] The description of the light emitting device 1 is continued.

[0124] In the light emitting device 1, the polarization ratio of light emitted from one or more semiconductor laser elements 20 disposed on the sub-substrate 30 and oscillating in the TM mode is greater than or equal to 100. For example, when the light is used for image display, a polarization ratio of greater than or equal to 100 is sometimes required, and a light emitting device 1 that emits light with a good polarization ratio can be realized. It should be noted that the value of the polarization ratio can be a value obtained by measuring the light emitted from the semiconductor laser element 20 and based on the measurement result.

[0125] In the light emitting device 1, the polarization ratio of light emitted from one or more semiconductor laser elements 20 disposed on the submount 30 and oscillating in the TM mode is greater than 150. The value of the polarization ratio may be a value obtained by measuring the light emitted from the semiconductor laser element 20 and based on the measurement result.

[0126] The one or more semiconductor laser elements 20 may include one or more semiconductor laser elements 20 oscillating in a TM mode and one or more semiconductor laser elements 20 oscillating in a TE mode.

[0127] Here, a semiconductor laser element 20 included in one or more semiconductor laser elements 20 and oscillating in TM mode is referred to as a first semiconductor laser element 20A, and a semiconductor laser element 20 included in one or more semiconductor laser elements 20 and oscillating in TE mode is referred to as a second semiconductor laser element 20B.

[0128] One or more first semiconductor laser elements 20A are respectively arranged on the sub-substrate 30. One or more second semiconductor laser elements 20B may be arranged on a sub-substrate different from the sub-substrate 30. For example, one or more second semiconductor laser elements 20B may include the semiconductor laser element 20 arranged on the above-mentioned sub-substrate 99. In addition, one or more second semiconductor laser elements 20B may include the semiconductor laser element 20 arranged on the sub-substrate 30.

[0129] The second semiconductor laser element 20B has a smaller advantage in polarization ratio than the first semiconductor laser element 20A due to being arranged on the sub-substrate 30 , and can be arranged on a sub-substrate different from the sub-substrate 30 in terms of characteristics different from the polarization ratio (eg, heat dissipation).

[0130] Here, the sub-substrate on which the first semiconductor laser element 20A is arranged is referred to as a first sub-substrate 30A, and the sub-substrate on which the second semiconductor laser element 20B is arranged is referred to as a second sub-substrate 30B.

[0131] In light emitting device 1 , first sub-substrate 30A and second sub-substrate 30B are disposed on mounting surface 11D. In light emitting device 1 , second sub-substrate 30B may be a sub-substrate that does not include at least a portion of all materials included in sub-substrate 30 or includes materials different from all materials included in sub-substrate 30 .

[0132] The sub-substrate 30 is used for at least one first sub-substrate 30A among one or more first sub-sub-substrates 30A. The sub-substrate 99 can be used for at least one second sub-substrate 30B among one or more second sub-substrates 30B. It should be noted that the sub-substrate 30 can also be used for at least one second sub-substrate 30B among one or more second sub-substrates 30B.

[0133] In the light emitting device 1, one or more first semiconductor laser elements 20A include a semiconductor laser element 20 that emits red light. The semiconductor laser element 20 may be a semiconductor laser element including an active layer made of a GaAs-based material.

[0134] In the light emitting device 1, one or more second semiconductor laser elements 20B include semiconductor laser elements 20 that emit light of a color different from that of the light emitted from one or more first semiconductor laser elements 20A. At least one second semiconductor laser element 20B emits light of a color different from that of the light emitted from the first semiconductor laser element 20A.

[0135] In the light emitting device 1, one or more second semiconductor laser elements 20B include a semiconductor laser element 20 that emits blue light or green light. The semiconductor laser element 20 may be a semiconductor laser element including an active layer made of a GaN-based material.

[0136] The polarization ratio (TE / TM) of the light emitted from the first semiconductor laser element 20A is smaller than the polarization ratio (TM / TE) of the light emitted from the second semiconductor laser element 20B.

[0137] In the light emitting device 1, the value of the polarization ratio (TM / TE) of the light emitted from the second semiconductor laser element 20B disposed on the second sub-substrate 30B as the sub-substrate 99 is greater than the polarization ratio (TE / TM) of the light emitted from the first semiconductor laser element 20A disposed on the first sub-substrate 30A as the sub-substrate 30. In this way, since the second semiconductor laser element 20B already has a sufficient polarization ratio, by disposing the first semiconductor laser element 20A on the sub-substrate 30, in the light emitting device 1, the polarization ratio of the light emitted from one or more semiconductor laser elements 20 can be made to be a good value.

[0138] In the light emitting device 1, the second sub-substrate 30B may be made of the same material as the upper second metal layer 35A of the first sub-substrate 30A and may have a metal layer thicker than the upper second metal layer 35A. Thus, the second sub-substrate 30B having better heat dissipation than the first sub-substrate 30A can be formed and used for the second semiconductor laser element 20B.

[0139] In the light emitting device 1, the second sub-substrate 30B has a ceramic substrate, and has a metal layer on the upper side of the ceramic substrate that is made of the same material as the upper second metal layer 35A of the first sub-substrate 30A and has a greater thickness than the upper second metal layer 35A, and may also have a metal layer on the lower side of the ceramic substrate that is made of the same material as the lower second metal layer 35B of the first sub-substrate 30A and has a greater thickness than the lower second metal layer 35B. Thus, the second sub-substrate 30B having better heat dissipation than the first sub-substrate 30A can be formed and used for the second semiconductor laser element 20B.

[0140] In the light emitting device 1, the one or more semiconductor laser elements 20 include a first semiconductor laser element 20A that emits red light, a second semiconductor laser element 20B that emits green light, and a second semiconductor laser element 20B that emits blue light. In addition, the value of the polarization ratio of the red light emitted from the light emitting device 1 is 100 or more, the value of the polarization ratio of the green light emitted from the light emitting device 1 is 200 or more, and the value of the polarization ratio of the blue light emitted from the light emitting device 1 is 200 or more. In this way, the light emitting device 1 that emits RGB light with a good polarization ratio can be realized.

[0141] In the light emitting device 1, one or more first semiconductor laser elements 20A include a semiconductor laser element 20 having a plurality of emitters. The semiconductor laser element 20 can emit red light.

[0142] In the light emitting device 1, one or more first semiconductor laser elements 20A include a semiconductor laser element 20 mounted on a first sub-substrate 30A by junction-down. The semiconductor laser element 20 is capable of emitting red light. In addition, the semiconductor laser element 20 may also have a plurality of emitters. If the tensile strain of the sub-substrate 30 affects the polarization ratio, the area in contact with the sub-substrate 30 may be increased on the side having a plurality of emitters when mounted by junction-down. Therefore, there is a possibility that a difference may occur in the influence of the polarization ratio caused by the sub-substrate 30 between the first semiconductor laser element 20A having one emitter and the first semiconductor laser element 20A having a plurality of emitters.

[0143] In the light emitting device 1, one or more reflecting components 40 are arranged in the internal space of the package 10. One or more reflecting components 40 are arranged on the mounting surface 11D. One or more reflecting components 40 have one or more light reflecting surfaces. Light emitted from one or more semiconductor laser elements 20 is reflected by one or more light reflecting surfaces. The light reflecting surfaces are inclined at an angle of 45 degrees relative to the traveling direction of light passing through the optical axis. The light reflected by the light reflecting surfaces travels upward. The main part of the plurality of lights is irradiated to the one or more light reflecting surfaces.

[0144] The reflecting member 40 can be provided one-to-one with the semiconductor laser element 20. That is, the reflecting member 40 is arranged in the same number as the number of the semiconductor laser elements 20. The size and shape of any reflecting member 40 are the same. The light reflecting surface of one reflecting member 40 is irradiated with the main part of light from one semiconductor laser element 20. In addition, the light reflecting surface of one reflecting member 40 can also be irradiated with the main part of light from a plurality of semiconductor laser elements 20.

[0145] The light reflecting surface of the reflecting member 40 reflects more than 90% of the main part of the irradiated light. It should be noted that the light emitting device 1 may not include the reflecting member 40. In this case, for example, the light emitting surface of the semiconductor laser element 20 faces the upper surface.

[0146] The light emitting device 1 may include a plurality of reflecting members 40. The plurality of reflecting members 40 are arranged in a direction same as the direction in which the plurality of semiconductor laser elements 20 are arranged in a plan view. The optical axes of the plurality of lights reflected by one or more light reflecting surfaces are parallel to each other.

[0147] In the light emitting device 1, one or more protection elements 50 are arranged on the base member. One or more protection elements 50 are arranged on the wiring pattern. It should be noted that it can also be arranged at a position other than the wiring pattern. For example, it can also be arranged on the sub-base 30. One or more protection elements 50 are electrically connected to the wiring pattern. The protection element 50 is set one-to-one with respect to the circuit that electrically connects one or more semiconductor laser elements 20.

[0148] In the light emitting device 1, the wiring 60 is bonded to the wiring pattern. The light emitting device 1 includes a plurality of wirings 60. The plurality of wirings 60 electrically connect one or a plurality of semiconductor laser elements 20 to the base member.

[0149] One or more wirings 60 are bonded to each step portion 12C. The wirings 60 that electrically connect the first semiconductor laser element 20A and the base member and the wirings 60 that electrically connect the second semiconductor laser element 20B and the base member are bonded to different step portions 12C.

[0150] In the light emitting device 1, the cover member is arranged on the upper surface of the base member. In addition, by bonding the cover member to the base member, a closed space surrounded by the base member and the cover member is generated. This space is the internal space of the package 10, and is a space where one or more semiconductor laser elements 20 are arranged.

[0151] By joining the cover member to the base member under a predetermined atmosphere, an airtight closed space is formed. By airtightly sealing the space in which the semiconductor laser element 20 is arranged, it is possible to suppress quality degradation caused by dust collection. The cover member is translucent to the light emitted from the semiconductor laser element 20. More than 90% of the main part of the light emitted from the semiconductor laser element 20 is emitted to the outside through the cover member.

[0152] In the light emitting device 1 , the polarization ratio of light emitted from the first semiconductor laser element 20A from the package 10 is greater than or equal to 100. The polarization ratio may be a value obtained by measuring light emitted from the semiconductor laser element 20 and from the package 10 based on the measurement result.

[0153] The optical component 80 is disposed above the cover member. The optical component 80 is bonded to the cover member. A plurality of lights emitted from the cover member are incident on the incident surface of the optical component 80. The lights incident on the incident surface of the optical component 80 are emitted from the lens surface.

[0154] In a plan view, the optical component 80 is configured so that one or more lens surfaces overlap with different semiconductor laser elements 20. A major portion of light emitted from different semiconductor laser elements 20 is emitted from the one or more lens surfaces. One semiconductor laser element 20 corresponds to one lens surface, and light from the corresponding semiconductor laser element 20 is emitted from each lens surface.

[0155] In the light emitting device 1, the value of the polarization ratio of the light from the first semiconductor laser element 20A emitted from the optical component 80 is greater than 100. It should be noted that the value of the polarization ratio may be a value obtained by measuring the light emitted from the semiconductor laser element 20 and emitted from the optical component 80 and based on the measurement result. It should be noted that the value may also be the light that passes through the package 10 before entering the optical component 80.

[0156] In the light emitting device 1, the value of the polarization ratio of the light emitted from the first semiconductor laser element 20A from the light emitting device 1 is greater than or equal to 100. It should be noted that the value of the polarization ratio may be a value obtained based on the measurement result of any one of the light emitted from the semiconductor laser element 20, the light emitted from the package 10, or the light emitted from the optical component 80. For example, in the case of the light emitting device 1 not including the cover 17, it may be said that the value is obtained based on the measurement result of any one of the light emitted from the semiconductor laser element 20 or the light emitted from the optical component 80.

[0157] The embodiments of the present invention have been described above, but the light-emitting device of the present invention is not strictly limited to the light-emitting device of the embodiments. That is, the present invention is not impossible to implement as long as it is not limited to the appearance and structure of the light-emitting device disclosed by the embodiments. The present invention can be applied without fully possessing all the constituent elements. For example, in the case where a part of the constituent elements of the light-emitting device disclosed in the embodiments is not recorded in the claims, the design freedom of those skilled in the art such as substitution, omission, deformation of shape, change of material, etc. is recognized for the constituent elements of the part, and on this basis, the invention recorded in the claims is determined to be applicable.

[0158] In this specification, the following technical matters are disclosed through the contents described so far.

[0159] (Item 1) A light-emitting device comprises: a first sub-substrate having a ceramic substrate containing AlN and a plurality of upper metal layers arranged on the upper surface side of the ceramic substrate; a first semiconductor laser element, which is arranged on the upper surface of the first sub-substrate and oscillates in a TM mode; the plurality of upper metal layers include one or more upper first metal layers, and the upper first metal layer has a metal layer containing at least Ni.

[0160] (Item 2) A light-emitting device according to Item 1, wherein the multiple upper metal layers include a topmost metal layer located at the top of the multiple upper metal layers, and the one or more upper first metal layers are intermediate metal layers located between the ceramic substrate and the topmost metal layer.

[0161] (Item 3) The light emitting device according to Item 2, wherein the uppermost metal layer is a metal layer containing Au or a metal layer containing an AuSn alloy.

[0162] (Item 4) A light-emitting device according to any one of Items 1 to 3, wherein the plurality of upper metal layers includes an upper second metal layer disposed between the ceramic substrate and the one or more upper first metal layers on the upper surface side of the ceramic substrate, and the thickness of the upper second metal layer is greater than the thickness of the one or more upper first metal layers.

[0163] (Item 5) A light-emitting device according to any one of Items 1 to 4, wherein the plurality of upper metal layers include one or more upper third metal layers on the upper surface side of the ceramic substrate, the upper third metal layer having a metal layer containing at least Pt and arranged on the upper surface side of the one or more upper first metal layers.

[0164] (Item 6) A light-emitting device according to any one of Items 1 to 5, wherein the first sub-substrate comprises: one or more lower first metal layers, which have a metal layer containing at least Ni and are arranged on the lower surface side of the ceramic substrate; a lower second metal layer, which is arranged between the ceramic substrate and the one or more lower first metal layers on the lower surface side of the ceramic substrate, and a metal layer containing at least Pt is not arranged on the lower surface side of the ceramic substrate.

[0165] (Item 7) The light emitting device according to any one of Items 1 to 6, further comprising a mounting component having a mounting surface on which the first sub-substrate is arranged and made of metal or ceramic as a main material.

[0166] (Item 8) The light emitting device according to any one of Items 1 to 7, wherein the first semiconductor laser element emits red light.

[0167] (Item 9) The light emitting device according to any one of Items 1 to 8, wherein the first semiconductor laser element has a plurality of emitters.

[0168] (Item 10) The light emitting device according to any one of Items 1 to 9, wherein the first semiconductor laser element is mounted by lower bonding to the first sub-substrate.

[0169] (Item 11) The light emitting device according to any one of Items 1 to 10, wherein a value of a polarization ratio of light from the first semiconductor laser element emitted from the light emitting device is 100 or more.

[0170] (Item 12) The light emitting device according to Item 7, further comprising: a second semiconductor laser element oscillating in a TE mode; and a second sub-substrate on which the second semiconductor laser element is arranged, wherein the second sub-substrate is arranged on the mounting surface.

[0171] (Item 13) The light emitting device according to Item 12, wherein the second semiconductor laser element emits light having a color different from that of the light emitted from the first semiconductor laser element.

[0172] (Item 14) The light-emitting device according to Item 12 or 13, wherein the second sub-substrate does not contain at least a part of all materials contained in the first sub-substrate, or contains a material different from all materials contained in the first sub-substrate.

[0173] (Item 15) A light-emitting device comprises: a first sub-substrate having a ceramic substrate containing AlN and a plurality of lower metal layers arranged on the lower surface side of the ceramic substrate; a first semiconductor laser element arranged on the upper surface of the first sub-substrate and oscillating in a TM mode; the plurality of lower metal layers including one or more lower first metal layers, the lower first metal layer having a metal layer containing at least Ni.

[0174] (Item 16) A light-emitting device according to Item 15, wherein the multiple lower metal layers include a lowest metal layer located at the bottom of the multiple lower metal layers, and the one or more lower first metal layers are intermediate metal layers located between the ceramic substrate and the lowest metal layer.

[0175] (Item 17) The light emitting device according to Item 16, wherein the lowermost metal layer is a metal layer containing an AuSn alloy.

[0176] (Item 18) A light-emitting device according to any one of Items 15 to 17, wherein the multiple lower metal layers include a lower second metal layer arranged between the ceramic substrate and the one or more lower first metal layers on the lower surface side of the ceramic substrate, and the thickness of the lower second metal layer is greater than the thickness of the one or more lower first metal layers.

[0177] (Item 19) The light emitting device according to any one of Items 15 to 18, further comprising a mounting component having a mounting surface on which the first sub-substrate is arranged and made of metal or ceramic as a main material.

[0178] (Item 20) The light emitting device according to any one of Items 15 to 19, wherein the first semiconductor laser element emits red light.

[0179] Industrial availability

[0180] The light emitting device described in the embodiments can be used for a projector, a vehicle headlight, a head mounted display, lighting, a display, and the like.

[0181] Description of Reference Numerals

[0182] 1: Light-emitting device

[0183] 10: Encapsulation

[0184] 11A: Top

[0185] 11B: Bottom

[0186] 11D: Mounting surface

[0187] 12C: Step

[0188] 14: Base

[0189] 15: Frame

[0190] 17: cover

[0191] 20: Semiconductor laser element

[0192] 20A: First semiconductor laser element

[0193] 20B: Second semiconductor laser element

[0194] 30: Sub-base

[0195] 31: Ceramic substrate

[0196] 32: Metal layer

[0197] 33A: Upper metal layer

[0198] 34A: Upper first metal layer

[0199] 35A: Upper second metal layer

[0200] 36A: The third metal layer on the upper side

[0201] 37A: Top metal layer

[0202] 38A: Bottom metal layer

[0203] 33B: Bottom metal layer

[0204] 34B: Lower first metal layer

[0205] 35B: Second metal layer on the bottom

[0206] 37B: Bottom metal layer

[0207] 38B: Top metal layer

[0208] 30A: First sub-substrate

[0209] 30B: Second sub-substrate

[0210] 40: Reflective parts

[0211] 50: Protection element

[0212] 60: Wiring

[0213] 80: Optical components

[0214] 99: Sub-base

Claims

1. A light emitting device comprising: A first sub-substrate having a ceramic substrate containing AlN and a plurality of upper metal layers provided on an upper surface side of the ceramic substrate; A first semiconductor laser element is disposed on the upper surface of the first sub-substrate and oscillates in a TM mode; The plurality of upper metal layers include one or more upper first metal layers, and the upper first metal layer has a metal layer containing at least Ni.

2. The light emitting device according to claim 1, wherein: The plurality of upper metal layers include an uppermost metal layer disposed at the top of the plurality of upper metal layers, The one or more upper first metal layers are intermediate metal layers disposed between the ceramic substrate and the uppermost metal layer.

3. The light emitting device according to claim 2, wherein: The uppermost metal layer is a metal layer containing Au or a metal layer containing an AuSn alloy.

4. The light emitting device according to any one of claims 1 to 3, wherein: The plurality of upper metal layers include an upper second metal layer disposed between the ceramic substrate and the one or more upper first metal layers on the upper surface side of the ceramic substrate, The thickness of the upper second metal layer is greater than the thickness of the one or more upper first metal layers.

5. The light emitting device according to any one of claims 1 to 4, wherein: The plurality of upper metal layers include one or more upper third metal layers on the upper surface side of the ceramic substrate, the upper third metal layer having a metal layer containing at least Pt provided on the upper surface side of the one or more upper first metal layers.

6. The light emitting device according to any one of claims 1 to 5, wherein: The first sub-substrate comprises: one or more lower first metal layers, which have a metal layer containing at least Ni and are arranged on the lower surface side of the ceramic substrate; a lower second metal layer, which is arranged between the ceramic substrate and the one or more lower first metal layers on the lower surface side of the ceramic substrate, and a metal layer containing at least Pt is not arranged on the lower surface side of the ceramic substrate.

7. The light emitting device according to any one of claims 1 to 6, wherein: The invention further comprises a mounting component having a mounting surface on which the first sub-substrate is arranged and mainly made of metal or ceramic.

8. The light emitting device according to any one of claims 1 to 7, wherein: The first semiconductor laser element emits red light.

9. The light emitting device according to any one of claims 1 to 8, wherein: The first semiconductor laser element has a plurality of emitters.

10. The light emitting device according to any one of claims 1 to 9, wherein: The first semiconductor laser element is mounted on the first sub-substrate by lower bonding.

11. The light emitting device according to any one of claims 1 to 10, wherein: The value of the polarization ratio of the light emitted from the first semiconductor laser element from the light emitting device is 100 or more.

12. The light emitting device according to claim 7, wherein: The device further comprises: a second semiconductor laser element oscillating in a TE mode; and a second sub-substrate on which the second semiconductor laser element is disposed. The second sub-substrate is arranged on the mounting surface.

13. The light emitting device according to claim 12, wherein: The second semiconductor laser element emits light of a color different from that of the light emitted from the first semiconductor laser element.

14. The light emitting device according to claim 12 or 13, wherein: The second sub-substrate does not include at least a part of all materials included in the first sub-substrate, or includes a material different from all materials included in the first sub-substrate.

15. A light emitting device comprising: A first sub-substrate having a ceramic substrate containing AlN and a plurality of lower metal layers provided on a lower surface side of the ceramic substrate; A first semiconductor laser element is disposed on the upper surface of the first sub-substrate and oscillates in a TM mode; The plurality of lower metal layers include one or more lower first metal layers, and the lower first metal layer has a metal layer containing at least Ni.

16. The light emitting device according to claim 15, wherein: The plurality of lower metal layers include a lowermost metal layer located at the bottom of the plurality of lower metal layers, The one or more lower first metal layers are intermediate metal layers disposed between the ceramic substrate and the lowermost metal layer.

17. The light emitting device according to claim 16, wherein: The lowermost metal layer is a metal layer containing AuSn alloy.

18. The light emitting device according to any one of claims 15 to 17, wherein: The plurality of lower metal layers include a lower second metal layer provided between the ceramic substrate and the one or more lower first metal layers on the lower surface side of the ceramic substrate, The thickness of the lower second metal layer is greater than the thickness of the one or more lower first metal layers.

19. The light emitting device according to any one of claims 15 to 18, wherein: The invention further comprises a mounting component having a mounting surface on which the first sub-substrate is arranged and mainly made of metal or ceramic.

20. The light emitting device according to any one of claims 15 to 19, wherein: The first semiconductor laser element emits red light.

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