Light-emitting device

Abstract

To achieve a compact light-emitting device.SOLUTION: A light-emitting device comprises: a substrate that has a top face; a plurality of sub-mounts that have first side faces and second side faces being side faces on the opposite side of the first side faces, and have the first side faces arranged side by side in a first direction on the top face of the substrate, in which their length in the first direction is smaller than their length in a second direction perpendicular to the first direction in top view; a plurality of semiconductor laser elements that individually have light emission surfaces, in which the light emission surfaces are arranged on the sub-mounts different from each other at positions closer to the first side faces than the second side faces; and a plurality of protection elements that are arranged on the sub-mounts different from each other at positions where the distance to the second faces is shorter than the distance from the semiconductor laser elements to the second faces.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a semiconductor laser device in which a laser element and a Zener diode electrically connected to the laser element are arranged above a submount. It also discloses that the arrangement of the Zener diode can protect the laser element from surge voltages and the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2019-169644 Summary of the Invention [Problem to be solved by the invention]

[0004] In the light emitting device of 1, there are cases where it is desired to mount a plurality of submounts on which semiconductor laser elements and protection elements are arranged. Also, there is a need for a compact light emitting device. [Means for solving the problem]

[0005] The light emitting device disclosed in the embodiment includes a base having an upper surface, a plurality of submounts having a first side surface and a second side surface opposite the first side surface, the first side surfaces being arranged in a first direction on the upper surface of the base, and the length in a second direction perpendicular to the first direction in a top view being greater than the length in the first direction, a plurality of semiconductor laser elements each having a light emitting surface and arranged in different submounts with the light emitting surface closer to the first side surface than the second side surface, and a plurality of protection elements each arranged in different submounts with the distance to the second side surface being shorter than the distance from the semiconductor laser element to the second side surface.

[0006] In at least one of the one or more inventions disclosed in the embodiments, it is expected that a small light emitting device can be realized in which a plurality of submounts, each of which has a semiconductor laser element and a protection element disposed thereon, are mounted. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of a light emitting device according to each embodiment. [Figure 2] FIG. 2 is a top view of the light emitting device according to each embodiment. [Figure 3] FIG. 3 is a cross-sectional view of the light emitting device according to the first embodiment taken along the line III-III in FIG. [Figure 4] FIG. 4 is a top view illustrating each component arranged inside the light emitting device according to the first embodiment. [Figure 5] FIG. 5 is a top view of the submount (first submount) according to the embodiment. [Figure 6] FIG. 6 is a top view of the submount (first submount) according to the embodiment, on which other components are arranged. [Figure 7] FIG. 7 is a cross-sectional view of the light emitting device according to the second embodiment taken along the line VII-VII in FIG. [Figure 8] FIG. 8 is a top view illustrating each component arranged inside the light emitting device according to the second embodiment. [Figure 9] FIG. 9 is a cross-sectional view of the light emitting device according to the third embodiment taken along the line IX-IX in FIG. [Figure 10] FIG. 10 is a top view illustrating each component arranged inside the light emitting device according to the third embodiment. [Figure 11] FIG. 11 is a top view of the second submount according to the embodiment. [Figure 12] FIG. 12 is a top view of the second submount according to the embodiment in a state where other components are arranged on the second submount. [Figure 13] FIG. 13 is a cross-sectional view of the light emitting device according to the fourth embodiment taken along the line XIII-XIII in FIG. [Figure 14] FIG. 14 is a top view illustrating each component arranged inside the light emitting device according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] In this specification and claims, polygons such as triangles and quadrilaterals are referred to as polygons, including shapes in which the corners of the polygons have been rounded, chamfered, corner-cut, rounded, etc. Furthermore, shapes in which processing has been applied not only to the corners (edges of the sides) but also to the middle portions of the sides are also referred to as polygons. In other words, shapes in which partial processing has been applied while retaining the polygonal base are included in the interpretation of "polygon" described in this specification and claims.

[0009] The same applies to words that describe specific shapes, such as trapezoids, circles, and irregularities, not just polygons. The same also applies when dealing with the sides that form the shape. In other words, even if the corners or middle part of a side are processed, the interpretation of "side" includes the processed part. Note that when distinguishing a "polygon" or "side" that has no processing from a processed shape, the word "strict" is added, for example, "strict quadrangle."

[0010] Furthermore, in this specification or claims, descriptions such as up and down, left and right, front and back, front and back, front and back, etc. merely describe relationships such as relative positions, orientations, directions, etc., and do not necessarily correspond to the relationships during use.

[0011] In addition, directions such as the X direction, Y direction, and Z direction may be indicated using arrows in the drawings, and the directions of these arrows are consistent among multiple drawings relating to the same embodiment.

[0012] Furthermore, in this specification, the terms "component" and "part" may be used when describing components, for example. 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 part in the manufacturing process. On the other hand, a "part" refers to an object that does not need to be physically handled as a single unit. For example, the term "part" is used when referring to a portion of a component.

[0013] The distinction between "component" and "part" above does not indicate a conscious intention to limit the scope of rights in the interpretation of the doctrine of equivalents. In other words, even if a component is described as a "component" in the claims, this does not mean that the applicant recognizes that treating this component as a single physical unit is essential for the application of the present invention.

[0014] Furthermore, in this specification or claims, when there are multiple elements of a certain type and they need to be distinguished from one another, the elements may be prefixed with "first" or "second." Furthermore, the objects distinguished between the specification and the claims may differ. Therefore, even if the claims describe elements with the same prefixes as the specification, the objects identified by these elements may not be the same between the specification and the claims.

[0015] For example, if there are elements in this specification that are distinguished by the notation "first," "second," and "third," and the elements marked "first" and "third" in this specification are described in the claims, the elements may be distinguished by the notation "first" and "second" in the claims for clarity. In this case, the elements marked "first" and "second" in the claims refer to the elements marked "first" and "third" in this specification, respectively. Note that this rule is not limited to elements, and can be applied rationally and flexibly to other objects as well.

[0016] Hereinafter, embodiments for carrying out the present invention will be described. Furthermore, specific embodiments for carrying out the present invention will be described with reference to the drawings. Note that the embodiments for carrying out the present invention are not limited to these specific embodiments. In other words, the illustrated embodiments are not the only embodiments in which the present invention can be realized. Note that the sizes and positional relationships of components shown in each drawing may be exaggerated for ease of understanding.

[0017] First Embodiment A light emitting device 1 according to a first embodiment will be described. FIGS. 1 to 6 are drawings for explaining an exemplary embodiment of the light emitting device 1. FIG. 1 is a perspective view of the light emitting device 1. FIG. 2 is a top view of the light emitting device 1. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. FIG. 4 is a top view showing the state of each component mounted on the base 10 of the light emitting device 1. FIG. 5 is a top view of the submount 30. FIG. 6 is a top view showing the state in which the semiconductor laser element 20 and the protection element 50 are mounted on the submount 30.

[0018] The light emitting device 1 includes a plurality of components, including a base 10, a plurality of semiconductor laser elements 20, a plurality of submounts 30, one or a plurality of reflecting members 40, a plurality of protective elements 50, a plurality of wirings 60, a cover member 70, and an optical member 80.

[0019] The light emitting device 1 may include other components. For example, the light emitting device 1 may include a light emitting element such as a light emitting diode or a semiconductor laser element in addition to the plurality of semiconductor laser elements 20. The light emitting device 1 may not include some of the components listed here.

[0020] First, each component will be described.

[0021] (Base 10) The base 10 has an upper surface 11A, a lower surface 11B, and one or more outer surfaces 11C. When viewed from above, the outer edge shape of the base 10 is rectangular. This rectangle can be a rectangle having long and short sides. In the illustrated base 10, the long side direction of this rectangle is the same as the X direction, and the short side direction is the same as the Y direction. Note that when viewed from above, the outer edge shape of the base 10 does not have to be rectangular.

[0022] A recessed shape is formed in the base 10. The recessed shape is formed from the upper surface 11A and recessed downward from the upper surface 11A. The recess is defined by the recessed shape of the base 10. This recess is surrounded by the upper surface 11A in a top view.

[0023] The inner edge of the upper surface 11A defines the outer edge of the recess. When viewed from above, the outer edge of the recess has a rectangular shape. This rectangle can have a long side and a short side. In the illustrated base 10, the long side of this rectangle is in the same direction as the X direction, and the short side is in the same direction as the Y direction. Note that the outer edge of this recess does not have to be rectangular.

[0024] The base 10 has a mounting surface 11D and one or more inner surfaces 11E. The mounting surface 11D is located below the top surface 11A and above the bottom surface 11B. The mounting surface 11D is an upper surface. The mounting surface 11D can be said to be an upper surface different from the top surface 11A. The one or more inner surfaces 11E are located above the mounting surface 11D. The one or more inner surfaces 11E intersect with the top surface 11A. The mounting surface 11D and the one or more inner surfaces 11E are included in the multiple surfaces that define the recess of the base 10.

[0025] One or more inner side surfaces 11E are provided perpendicular to the mounting surface 11D. Here, the perpendicularity allows for a difference of ±3 degrees. Note that the inner side surfaces 11E do not have to be perpendicular to the mounting surface 11D.

[0026] The base 10 has one or more step portions 12C. Each step portion 12C has an upper surface and an inner surface that intersects with the upper surface and extends downward from the upper surface. The upper surface of step portion 12C intersects with inner surface 11E. The inner surface of step portion 12C intersects with mounting surface 11D.

[0027] The step portion 12C is formed along a part or all of the inner side surface 11E in a top view. One or more step portions 12C are formed on the inside of the upper surface 11A in a top view. One or more step portions 12C are formed on the inside of one or more inner side surfaces 11E in a top view.

[0028] The base 10 may have a plurality of step portions 12C. The plurality of step portions 12C includes a step portion 12C formed along the inner surface 11E in a top view. The plurality of step portions 12C includes a step portion 12C formed along the entire inner surface 11E in a top view.

[0029] The multiple step portions 12C include, when viewed from above, a step portion 12C (hereinafter referred to as the first step portion) formed along a certain inner surface 11E (hereinafter referred to as the first inner surface), and a step portion 12C (hereinafter referred to as the second step portion) formed along another inner surface 11E (hereinafter referred to as the second inner surface).

[0030] The first inner surface 11E and the second inner surface 11E face each other. The first step portion 12C may be formed only along the first inner surface 11E. The second step portion 12C may be formed only along the second inner surface 11E. In top view, no step portion 12C is provided between the step portions 12C formed along the opposing inner surfaces 11E.

[0031] The base 10 does not have any step portions other than the plurality of step portions 12C on the inside of the upper surface 11A in a top view, and the plurality of step portions 12C can be composed of only two step portions 12C. The plurality of step portions 12C can be composed of only a first step portion 12C and a second step portion 12C.

[0032] The plurality of step portions 12C includes step portions 12C formed along the inner surface 11E with a length of 50% to 100% of the length of the inner surface 11E in a direction parallel to the mounting surface 11D.

[0033] One or more wiring patterns 13 are provided on the upper surface of the step portion 12C. The wiring patterns 13 are electrically connected to other wiring patterns via wiring passing through the inside of the base 10. The other wiring patterns are provided, for example, on the lower surface of the base 10. Note that the wiring patterns 13 may be electrically connected to wiring patterns provided on the upper surface 11A or the outer surface 11C.

[0034] A plurality of wiring patterns 13 are provided on the upper surfaces of one or more step portions 12C. One or more wiring patterns 13 can be provided on each of the plurality of step portions 12C. The base 10 can have step portions 12C on whose upper surfaces a plurality of wiring patterns 13 are provided. By providing the wiring patterns 13 on the upper surfaces of the step portions 12C, it is possible to connect the wiring at a position higher than the mounting surface 11D. This may facilitate the wiring joining process.

[0035] The location where the wiring pattern 13 is provided on the base 10 does not have to be limited to the step portion 12C. The base 10 can be said to have a wiring portion provided for electrical connection, and in the illustrated base 10, the step portion 12C is also a wiring portion.

[0036] The base 10 can be formed primarily from ceramic, or may be formed by joining a bottom member having a mounting surface 11D formed primarily from a metal or a composite containing a metal, and a frame member having a wiring pattern 13 formed primarily from ceramic.

[0037] Here, the term "main material" refers to the material that accounts for the largest proportion of mass or volume in the target structure. Note that when the target structure is formed from a single material, that material is the main material. In other words, when a material is the main material, it means that the proportion of that material can be 100%.

[0038] Examples of ceramics include aluminum nitride, silicon nitride, aluminum oxide, and silicon carbide. Examples of metals include copper, aluminum, and iron. Alternatively, composites containing metals such as copper molybdenum, copper-diamond composites, and copper tungsten can be used.

[0039] (semiconductor laser element 20) The semiconductor laser element 20 has a light emitting surface from which light is emitted. The semiconductor laser element 20 has an upper surface, a lower surface, and multiple side surfaces. The upper surface or the side surface of the semiconductor laser element 20 serves as the light emitting surface. The shape of the upper surface of the semiconductor laser element 20 is a rectangle having long and short sides. However, the shape of the upper surface of the semiconductor laser element 20 does not have to be rectangular.

[0040] The semiconductor laser element 20 is a single-emitter semiconductor laser element. The semiconductor laser element 20 can also be a multi-emitter semiconductor laser element having multiple emitters. When a multi-emitter semiconductor laser element is used for the semiconductor laser element 20, the number of emitters is preferably two. Taking into consideration that the semiconductor laser element 20 may become larger as the number of emitters increases and the influence of heat dissipation, a semiconductor laser element with an appropriate number of emitters should be used.

[0041] For example, a semiconductor laser element that emits blue light or a semiconductor laser element that emits green light can be used as the semiconductor laser element 20. Alternatively, a semiconductor laser element that emits red light may be used as the semiconductor laser element 20. Alternatively, a semiconductor laser element that emits light of another color may be used as the semiconductor laser element 20.

[0042] Here, blue light refers to light whose peak emission wavelength is in the range of 420 nm to 494 nm, green light refers to light whose peak emission wavelength is in the range of 495 nm to 570 nm, and red light refers to light whose peak emission wavelength is in the range of 605 nm to 750 nm.

[0043] The semiconductor laser element 20 has a rectangular shape in top view with one opposite side as a long side and the other opposite side as a short side. Light (laser light) emitted from the semiconductor laser element 20 has a divergent shape. Divergent light is emitted from the light emitting end face (light emitting surface) of the semiconductor laser element 20.

[0044] The light emitted from the semiconductor laser element 20 forms an elliptical far-field pattern (hereinafter referred to as "FFP") in a plane parallel to the light emission end face. The FFP is the shape and light intensity distribution of the emitted light at a position away from the emission end face.

[0045] Here, the light passing through the center of the elliptical shape of the FFP, in other words, the light with peak intensity in the light intensity distribution of the FFP, is referred to as the light traveling along the optical axis or the light passing through the optical axis. Also, in the light intensity distribution of the FFP, the light with peak intensity is referred to as the light traveling along the optical axis or the light passing through the optical axis. 2 The light having the above intensity is called the main part of the light.

[0046] The FFP of the light emitted from the semiconductor laser element 20 has 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 emitting end facet. The stacking direction is the direction in which multiple semiconductor layers including the active layer are stacked in the semiconductor laser element 20. The direction perpendicular to the stacking direction can also be referred to as the in-plane direction of the semiconductor layers. 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 also be referred to as the slow axis direction of the semiconductor laser element 20.

[0047] Based on the light intensity distribution of FFP, 1 / e of the peak light intensity 2The angle at which light having this light intensity spreads is defined as the light spread angle of the semiconductor laser element 20. The light spread angle is 1 / e of the peak light intensity. 2 In the explanation of this specification, when simply referring to the "angle of light", it is assumed that the angle is 1 / e of the peak light intensity. 2 The divergence angle of light at a light intensity of 1000 nm is defined as the divergence angle of light in the fast axis direction.

[0048] The semiconductor laser element 20 that emits blue light or the semiconductor laser element 20 that emits green light may include a semiconductor laser element 20 that includes a nitride semiconductor. Examples of nitride semiconductors that can be used include GaN, InGaN, and AlGaN. The semiconductor laser element 20 that emits red light may include a semiconductor that includes an InAlGaP-based, GaInP-based, GaAs-based, or AlGaAs-based semiconductor.

[0049] (Submount 30) The submount 30 has a top surface 31, a bottom surface, and one or more side surfaces 32. When viewed from above, the submount 30 has an outer shape in which the length in one direction is greater than the length in the direction perpendicular to that direction. The top surface 31 is rectangular in shape. The top surface 31 can be rectangular in shape having short sides and long sides.

[0050] The submount 30 is configured in the shape of a rectangular parallelepiped. The distance between the upper surface 31 and the lower surface of the submount 30 is smaller than the distance between the other two opposing surfaces. This distance between the upper surface 31 and the lower surface is referred to as the thickness of the submount 30. Note that the shape of the submount 30 is not limited to a rectangular parallelepiped.

[0051] A placement area 33 is provided on the upper surface 31. Other components are placed in the placement area 33. The placement area 33 secures space for placing other components. The shape of the placement area 33 corresponds to the shape of the component to be placed there. A plurality of placement areas 33 are provided on the upper surface 31.

[0052] The length of the short side of the upper surface 31 is 500 μm or more and 1500 μm or less. The length of the long side of the upper surface 31 is 1000 μm or more and 3000 μm or less. The thickness of the submount 30 is 200 μm or more and 500 μm or less. The length of the long side of the upper surface 31 is 150% or more and 300% or less of the length of the short side.

[0053] The submount 30 can be made of, for example, silicon nitride, aluminum nitride, or silicon carbide. A metal film is provided on the placement region 33 for bonding with other components.

[0054] (Reflective member 40) The reflecting member 40 has a light-reflecting surface that reflects light. The light-reflecting surface is inclined with respect to the bottom surface. In other words, the positional relationship of the light-reflecting surface when viewed from the bottom surface is neither perpendicular nor parallel. A line connecting the bottom end and top end of the light-reflecting surface is inclined with respect to the bottom surface of the reflecting member 40. The angle of the light-reflecting surface with respect to the bottom surface, or the angle of the line connecting the bottom end and top end of the light-reflecting surface with respect to the bottom surface, is referred to as the inclination angle of the light-reflecting surface.

[0055] In the illustrated reflecting member 40, the light reflecting surface is flat and forms an inclination angle of 45 degrees with respect to the lower surface of the reflecting member 40. Note that the light reflecting surface does not have to be flat, and may be, for example, a curved surface. Furthermore, the inclination angle of the light reflecting surface does not have to be 45 degrees.

[0056] The reflecting member 40 can be primarily made of glass, metal, or the like. The primary material is preferably a heat-resistant material, such as glass, such as quartz or BK7 (borosilicate glass), or metal, such as aluminum. The reflecting member 40 can also be made primarily of Si. If the primary material is a reflective material, the light-reflecting surface can be formed from the primary material. When the light-reflecting surface is formed separately from the primary material, the light-reflecting surface can be formed using, for example, metal, such as Ag or Al, or a dielectric multilayer film, such as Ta2O5 / SiO2, TiO2 / SiO2, or Nb2O5 / SiO2.

[0057] The light reflecting surface has a reflectance of 90% or more for the peak wavelength of light irradiated onto the light reflecting surface. This reflectance may be 95% or more. This reflectance can also be 99% or more. The light reflectance is 100% or less, or less than 100%.

[0058] (protective element 50) The protective element 50 is intended to prevent a specific element (such as a semiconductor laser element) from being destroyed by excessive current flowing through it. An example of the protective element 50 is a Zener diode. The Zener diode may be made of Si.

[0059] (Wiring 60) The wiring 60 is a linear conductive material with joints at both ends. The joints at both ends become joints with other components. The wiring 60 is, for example, a metal wire. Examples of metals that can be used include gold, aluminum, silver, and copper.

[0060] (lid member 70) The lid member 70 has a bottom surface and a top surface, and is configured in the shape of a rectangular parallelepiped flat plate. However, it does not have to be a rectangular parallelepiped. The lid member 70 is translucent, meaning that it transmits light. Here, translucency means that the light transmittance is 80% or more. However, it does not have to have a transmittance of 80% or more for all wavelengths of light. The lid member 70 may have a non-translucent region (a region that does not have translucency) in part.

[0061] The lid member 70 is formed primarily from glass. The primary material of the lid member 70 is a material that has high translucency. The lid member 70 is not limited to glass, and may be formed primarily from sapphire, for example.

[0062] (Optical member 80) The optical member 80 has an upper surface, a lower surface, and side surfaces. The optical member 80 exerts optical effects on incident light, such as reflection, transmission, and refraction, as well as optical effects such as focusing, diffusing, and collimating.

[0063] The optical element 80 may have one or more lens surfaces. The one or more lens surfaces are provided on the upper surface side of the optical element 80. Alternatively, the one or more lens surfaces may be provided on the lower surface side of the optical element 80. The upper and lower surfaces are flat. The one or more lens surfaces intersect with the upper surface. The one or more lens surfaces are surrounded by the upper surface in a top view. In a top view, the optical element 80 has a rectangular outer shape. The lower surface of the optical element 80 is rectangular.

[0064] The portion of optical element 80 that overlaps one or more lens surfaces when viewed from above is referred to as the lens portion. The portion of optical element 80 that overlaps with the upper surface when viewed from above is referred to as the non-lens portion. When the lens portion is bisected by an imaginary plane including the upper surface, the lens surface side is referred to as the lens-shaped portion, and the lower surface side is referred to as the flat-plate-shaped portion. The lower surface of the lens portion is a part of the lower surface. In optical element 80, the lower surface is composed of the lower surface of the lens portion and the lower surface of the non-lens portion.

[0065] The illustrated optical member 80 has multiple lens surfaces. The multiple lens surfaces are formed in a continuous line in one direction. The optical member 80 has five lens surfaces, and is formed so that the vertices of these five lens surfaces are aligned on a straight line. This straight line is in the same direction as the X direction.

[0066] Here, the direction in which the lens surfaces are aligned in a top view is referred to as the connecting direction. The length of the lens surfaces in the connecting direction in a top view is greater than the length in the direction perpendicular to this direction. In the illustrated optical member 80, the connecting direction is the same as the X direction.

[0067] The optical member 80 has high light transmittance. The optical member 80 has high light transmittance in both the lens portion and the non-lens portion. Moreover, the optical member 80 as a whole has high light transmittance. The optical member 80 can be formed using glass such as BK7, for example.

[0068] Next, a light emitting device 1 including the above-mentioned components will be described. In the following description of the light emitting device 1, the description of a single component also applies to each of the multiple identical components, as long as it is consistent with the drawings related to the light emitting device 1. In other words, if there are multiple identical components in the drawings and the description of a single component also applies to each of the multiple identical components from the drawings, this description also applies to each of the multiple identical components.

[0069] (Light-emitting device 1) In the light emitting device 1, the semiconductor laser element 20 is mounted on a submount 30. The semiconductor laser element 20 is disposed on an upper surface 31 of the submount 30. The semiconductor laser element 20 is disposed in an arrangement region 33 provided on the upper surface 31. The semiconductor laser element 20 emits blue light.

[0070] The plurality of semiconductor laser elements 20 are arranged on different submounts 30. All of the plurality of semiconductor laser elements 20 emit light of the same color. A light emitting element may be arranged on the submount 30 on which the semiconductor laser elements 20 are arranged. In consideration of heat dissipation, it may be desirable that no light emitting element other than one semiconductor laser element 20 is arranged on one submount 30.

[0071] The semiconductor laser element 20 is disposed so that its light emitting surface is located near a side surface 32 of the submount 30. Here, the side surface 32 located near the light emitting surface will be referred to as a first side surface 32A. Furthermore, the side surface 32 of the submount 30 opposite the first side surface 32A will be referred to as a second side surface 32B. The first side surface 32A is the side surface 32 that intersects with a short side of the top surface 31. The second side surface 32B is the side surface 32 that intersects with a short side that forms a pair with the short side where the first side surface 32A and the top surface 31 intersect. The semiconductor laser element 20 is disposed on the submount 30 so that its light emitting surface is closer to the first side surface 32A than to the second side surface 32B.

[0072] In top view, the semiconductor laser element 20 is disposed at a position where an imaginary straight line L1, which passes through the center of the short side of the upper surface 31 and is parallel to the long side, passes through both the light emitting surface and the side surface opposite to the light emitting surface of the semiconductor laser element 20. Hereinafter, the imaginary straight line will be referred to as a "virtual line."

[0073] In the light emitting device 1, the protective element 50 is mounted on the submount 30. The protective element 50 is disposed on the upper surface 31 of the submount 30. The protective element 50 is disposed in an arrangement region 33 provided on the upper surface 31. The protective element 50 is disposed on the submount 30 on which the semiconductor laser element 20 is disposed. A plurality of protective elements 50 are disposed on different submounts 30.

[0074] With regard to the semiconductor laser element 20 and the protection element 50 disposed on the submount 30, the protection element 50 is disposed on the submount 30 at a position where the distance from the protection element 50 to the second side surface 32B is shorter than the distance from the semiconductor laser element 20 to the second side surface 32B. The longest distance from the second side surface 32B to the protection element 50 is shorter than the shortest distance from the second side surface 32B to the semiconductor laser element 20. The protection element 50 is disposed near the second side surface 32B.

[0075] The protective element 50 is disposed at a position where the imaginary line L1 does not pass when viewed from above. With regard to the semiconductor laser element 20 and the protective element 50 disposed on the submount 30, the protective element 50 is disposed at a position where the imaginary line L2 passing through the center of the length of the semiconductor laser element 20 in the direction parallel to the light emitting surface and perpendicular to the light emitting surface does not pass when viewed from above. By disposing the protective element 50 at such a position, it is possible to reduce the influence of light leaking from the side surface opposite to the light emitting surface.

[0076] The placement region 33 where the semiconductor laser element 20 is placed and the placement region 33 where the protection element 50 is placed are different and do not overlap in top view. Here, the former placement region 33 is referred to as the first placement region 33A, and the latter placement region 33 is referred to as the second placement region 33B. In top view, the first placement region 33A and the second placement region 33B are arranged so that there is an imaginary line L3 that passes through the first placement region 33A and the second placement region 33B in a direction parallel to the long side of the top surface 31. This allows the length of the short side of the top surface 31 to be reduced.

[0077] In the submount 30, the first placement region 33A and the second placement region 33B may be realized by a single placement region 33 that is partially connected. In this case, the boundary of the first placement region 33A and the boundary of the second placement region 33B only need to be determined substantially. That is, taking into consideration component tolerances and mounting accuracy, the minimum area that needs to be secured for placing the semiconductor laser element 20 can be defined as the first placement region 33A, and the minimum area that needs to be secured for placing the protection element 50 can be defined as the second placement region 33B.

[0078] In the light emitting device 1, the submount 30 is mounted on the base 10. The submount 30 is disposed on the mounting surface 11D of the base 10. A plurality of submounts 30 are arranged side by side on the mounting surface 11D. The plurality of submounts 30 are arranged side by side in the longitudinal direction of the base 10. The plurality of submounts 30 are arranged side by side in the direction of the long sides of the base 10.

[0079] Here, the direction in which the multiple submounts 30 are lined up in top view is referred to as the first direction. In the light emitting device 1, the multiple semiconductor laser elements 20 are arranged in the first direction. In the illustrated light emitting device 1, the first direction is the same as the X direction. In top view, the direction parallel to the light emission surfaces of the semiconductor laser elements 20 arranged on the submounts 30 is the same as the X direction.

[0080] The multiple submounts 30 are arranged so that their first side surfaces 32A are aligned in the first direction. The multiple semiconductor laser elements 20 are arranged so that their light emitting surfaces are aligned in the first direction. In a top view, the length of the submount 30 in a direction perpendicular to the first direction (hereinafter referred to as the second direction) is greater than the length in the first direction. The length of the submount 30 in the second direction is 150% or more and 300% or less of the length in the first direction. In a top view, the side where the upper surface 31 of the submount 30 intersects with the first side surface 32A is parallel to the first direction.

[0081] The multiple submounts 30 are arranged at intervals of 50 μm or more and 300 μm or less in the first direction. The maximum value of the interval between adjacent submounts 30 in the multiple submounts 30 is 50% or less of the length of the submounts 30 in the first direction. The length of the submounts 30 in the first direction is 2.5 times or more and 5 times or less of the minimum value of the interval between adjacent submounts 30 in the multiple submounts 30. By specifying the size and arrangement interval of the submounts 30 so as to satisfy one or more of these conditions, it is possible to arrange a larger number of submounts 30, each with a semiconductor laser element 20 arranged thereon, in the first direction in a compact light-emitting device.

[0082] In a top view, the distance from the long side of the upper surface 31 included in the region where the protection element 50 is arranged, among the regions obtained by dividing the upper surface 31 in half by the virtual line L2, to the first arrangement region 33A is shorter than the distance from the second side surface 32B to the first arrangement region 33A. Furthermore, the distance from this long side to the first arrangement region 33A is shorter than the length in the second direction of the second arrangement region 33B. By reducing the length of the short side of the submount 30 so as to satisfy these conditions, more submounts 30 can be arranged in a compact light emitting device 1.

[0083] In top view, the distance from the long side of the upper surface 31 included in the region where the protection element 50 is arranged, among the regions obtained by dividing the upper surface 31 in half by the imaginary line L2, to the first arrangement region 33A is shorter than the length in the first direction of the second arrangement region 33B. This makes it possible to reduce the length in the short side direction of the submount 30, and to arrange more submounts 30 in a compact light emitting device.

[0084] With respect to the submount 30 and the semiconductor laser element 20 disposed on the submount 30, the length of the short side of the upper surface 31, as viewed from above, is 300% or more and 600% or less of the length in a direction parallel to the light emitting surface of the semiconductor laser element 20. Alternatively, the length of the submount 30 in a first direction, as viewed from above, is 300% or more and 600% or less of the length of the semiconductor laser element 20 in the first direction.

[0085] With regard to the submount 30 and the protection element 50 disposed on the submount 30, the length of the short side of the upper surface 31, as viewed from above, is 200% to 500% of the length of the protection element 50 in a direction parallel to the light emission surface of the semiconductor laser element 20. Alternatively, the length of the submount 30 in the first direction, as viewed from above, is 200% to 500% of the length of the protection element 50 in the first direction.

[0086] With regard to the submount 30, and the semiconductor laser element 20 and protection element 50 disposed on the submount 30, the length of the submount 30 in the first direction, as viewed from above, is 1.5 to 2.5 times the sum of the length of the semiconductor laser element 20 in the first direction and the length of the protection element 50 in the first direction. By specifying the length of the submount 30 in the first direction so as to satisfy one or more of these conditions, it is possible to line up more submounts 30, each with a semiconductor laser element 20 disposed thereon, in the first direction.

[0087] With respect to the submount 30 and the semiconductor laser element 20 disposed on the submount 30, the length of the long side of the upper surface 31, as viewed from above, is 105% to 150% of the length in the direction perpendicular to the light emission surface of the semiconductor laser element 20. Alternatively, the length of the submount 30 in the second direction, as viewed from above, is 105% to 150% of the length of the semiconductor laser element 20 in the second direction.

[0088] With regard to the submount 30, the semiconductor laser element 20, and the protection element 50 disposed on the submount 30, the length of the submount 30 in the second direction, as viewed from above, is greater than the sum of the length of the semiconductor laser element 20 in the second direction and the length of the protection element 50 in the second direction by 150 μm to 500 μm. This reduces the size of the submount 30 in the second direction, allowing the light emitting device 1 to be manufactured in a compact size.

[0089] The illustrated light emitting device 1 is disclosed as a light emitting device in which five submounts 30 are arranged in the first direction as the plurality of submounts 30. In this way, in the light emitting device 1, the plurality of submounts 30 can include five or more submounts.

[0090] Also, in the illustrated light emitting device 1, a light emitting device is disclosed in which the plurality of semiconductor laser elements 20 is configured with the same number of semiconductor laser elements 20 as the number of submounts 30 arranged on the mounting surface 11D of the base 10. Furthermore, a light emitting device is disclosed that does not have any light emitting elements including semiconductor laser elements other than the plurality of semiconductor laser elements 20.

[0091] In the light emitting device 1, the light emitting surfaces of the multiple semiconductor laser elements 20 each face sideways. The light emitting surfaces of the multiple semiconductor laser elements 20 each face the same direction. Light traveling sideways is emitted from the light emitting surfaces of the semiconductor laser elements 20. FFP light with its fast axis direction perpendicular to the mounting surface 11D is emitted from the light emitting surfaces of the semiconductor laser elements 20. The divergence angle in the slow axis direction of each semiconductor laser element 20 is 20 degrees or less. The divergence angle is an angle greater than 0 degrees.

[0092] In the light emitting device 1, one or more reflecting members 40 are disposed on the base 10. The reflecting members 40 are disposed on the mounting surface 11D. The reflecting members 40 have light reflecting surfaces. Light emitted from the multiple 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 with respect to the traveling direction of the light passing through the optical axis. The light reflected by the light reflecting surfaces travels upward. The light reflecting surfaces of the reflecting member 40 are irradiated with light from one or more main portions.

[0093] The reflecting members 40 can be provided one-to-one with respect to the semiconductor laser elements 20. In other words, the same number of reflecting members 40 as the number of semiconductor laser elements 20 are provided. The multiple reflecting members 40 are arranged side by side in the first direction when viewed from above. All of the reflecting members 40 have the same size and shape. The light-reflecting surface of the reflecting member 40 reflects 90% or more of the main part of the light that is irradiated. Note that one reflecting member 40 may be provided for multiple semiconductor laser elements 20. Also, one reflecting member 40 may be provided for all of the semiconductor laser elements 20. Alternatively, the light-emitting device 1 may not have a reflecting member 40.

[0094] In the light emitting device 1, the wiring 60 is joined to the wiring pattern 13. 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 10.

[0095] In the light emitting device 1, the lid member 70 is disposed on the upper surface of the base 10. The lid member 70 is located above the stepped portion 12C. By joining the lid member 70, a closed space surrounded by the base 10 and the lid member 70 is created. This space is where the semiconductor laser element 20 is disposed.

[0096] By joining the lid member 70 to the base 10 under a predetermined atmosphere, a hermetically sealed closed space is created. By hermetically sealing the space in which the semiconductor laser element 20 is disposed, quality deterioration due to dust collection can be suppressed. The lid member 70 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 passes through the lid member 70 and is emitted to the outside.

[0097] The optical member 80 is disposed above the cover member 70. The optical member 80 is bonded to the cover member 70. The plurality of light beams emitted from the cover member 70 are incident on the incident surface of the optical member 80. The light beams incident on the incident surface of the optical member 80 are emitted from the lens surface.

[0098] The optical member 80 is arranged such that, in top view, each of the plurality of lens surfaces overlaps a different semiconductor laser element 20. A main portion of light emitted from each of the different semiconductor laser elements 20 is emitted from each of one or more lens surfaces. One lens surface corresponds to one semiconductor laser element 20, and light from the corresponding semiconductor laser element 20 is emitted from each lens surface.

[0099] Second Embodiment A light emitting device 2 according to a second embodiment will be described. FIGS. 1, 2, and 5 to 8 are drawings for explaining an exemplary embodiment of the light emitting device 2. FIG. 1 is a perspective view of the light emitting device 2. FIG. 2 is a top view of the light emitting device 2. FIG. 5 is a top view of the submount 30. FIG. 6 is a top view showing a state in which a semiconductor laser element 20 and a protection element 50 are mounted on the submount 30. FIG. 7 is a cross-sectional view taken along the VII-VII line in FIG. 1. FIG. 8 is a top view showing the state of each component mounted on the base 10 of the light emitting device 1.

[0100] The light emitting device 2 includes a plurality of components, including a base 10, a plurality of semiconductor laser elements 20, a plurality of submounts 30, one or a plurality of reflecting members 40, a plurality of protective elements 50, a plurality of wirings 60, a cover member 70, and an optical member 80. The light emitting device 2 may include other components as well.

[0101] Each of these components is common to the first embodiment, and therefore the description of each component is the same as that of the first embodiment. The light emitting device 2 will be described below. The light emitting device 2 has different features from the light emitting device 1 of the first embodiment, but there are also some common features. Of the contents described for the light emitting device 1 in the first embodiment, those that do not cause inconsistencies based on Figures 1, 2, and 5 to 8 also apply to the light emitting device 2.

[0102] (Light-emitting device 2) In the light emitting device 2, the plurality of semiconductor laser elements 20 include a first semiconductor laser element 20A and a second semiconductor laser element 20B that emit light from their light emitting surfaces with different peak wavelengths. The light emitting device 2 has a plurality of first semiconductor laser elements 20A. The light emitting device 2 has a plurality of second semiconductor laser elements 20B.

[0103] The peak wavelength of light from the first semiconductor laser element 20A is shorter by 20 nm or more than the peak wavelength of light from the second semiconductor laser element 20B. The color of light emitted from the first semiconductor laser element 20A is different from the color of light emitted from the second semiconductor laser element 20B. In the illustrated light emitting device 2, the first semiconductor laser element 20A emits blue light, and the second semiconductor laser element 20B emits green light.

[0104] The length of the first semiconductor laser element 20A in a direction parallel to the light emitting surface is 95% to 105% of the length of the second semiconductor laser element 20B in a direction parallel to the light emitting surface. The multiple semiconductor laser elements 20 are aligned so that the lengths of the semiconductor laser elements in a direction parallel to the light emitting surface are approximately the same. This allows a submount 30 of the same size and shape to be used for each of the semiconductor laser elements 20.

[0105] The multiple first semiconductor laser elements 20A are arranged side by side in the first direction. The multiple second semiconductor laser elements 20B are arranged side by side in the first direction. In top view, on the mounting surface 11D, the first semiconductor laser elements 20A are arranged in one of two regions divided by an imaginary line L4 parallel to the second direction, and the second semiconductor laser elements 20B are arranged in the other region. In this case, the second semiconductor laser elements 20B are not arranged in one region, and the first semiconductor laser elements 20A are not arranged in the other region.

[0106] The base 10 has two wiring portions that face each other in a first direction in top view and have a plurality of semiconductor laser elements 20 arranged therebetween. One of the two wiring portions has a wiring pattern 13 for electrically connecting the first semiconductor laser element 20A, and the other has a wiring pattern 13 for electrically connecting the second semiconductor laser element 20B.

[0107] The plurality of wirings 60 include a plurality of first wirings 60A for electrically connecting the plurality of first semiconductor laser elements 20A and a plurality of second wirings 60B for electrically connecting the plurality of second semiconductor laser elements 20B. In the light emitting device 2, the plurality of first semiconductor laser elements 20A are electrically connected in series, and the plurality of second semiconductor laser elements 20B are electrically connected in series.

[0108] The plurality of first wirings 60A includes first wirings 60A bonded to a wiring portion of the base 10 and to the first semiconductor laser element 20A closest to the wiring portion or to the submount 30 on which the first semiconductor laser element 20A is disposed. The plurality of first wirings 60A also includes first wirings 60A bonded to a wiring portion of the base 10 and to the first semiconductor laser element 20A farthest from the wiring portion or to the submount 30 on which the first semiconductor laser element 20A is disposed. One of these two first wirings 60A is bonded to the wiring portion in one region of a region bisected by an imaginary line L5 that passes through the side surface opposite to the light emission surface of the first semiconductor laser element 20A and is parallel to the first direction, and the other first wiring 60A is bonded to the wiring portion in the other region.

[0109] The plurality of first wirings 60A include first wirings 60A bonded to a wiring portion of the base 10 and to the submount 30 on which the first semiconductor laser element 20A farthest from the wiring portion is disposed. The first wirings 60A are bonded to the submount 30 in a region where the protection element 50 is disposed, among the region bisected by the imaginary line L5 in top view. By using this region for bonding the wirings 60, the size of the submount 30 can be reduced, and a compact light-emitting device can be realized.

[0110] The plurality of second wirings 60B includes second wirings 60B bonded to the wiring portion of the base 10 and the second semiconductor laser element 20B closest to the wiring portion or the submount 30 on which the second semiconductor laser element 20B is disposed. The plurality of second wirings 60B also includes second wirings 60B bonded to the wiring portion of the base 10 and the second semiconductor laser element 20B farthest from the wiring portion or the submount 30 on which the second semiconductor laser element 20B is disposed. One of these two second wirings 60B is bonded to the wiring portion in one region of a region bisected by an imaginary line L6 that passes through the side surface opposite to the light emission surface of the second semiconductor laser element 20B and is parallel to the first direction, in a top view, and the other second wiring 60B is bonded to the wiring portion in the other region.

[0111] The plurality of second wirings 60B include second wirings 60B bonded to a wiring portion of the base 10 and to the submount 30 on which the second semiconductor laser element 20B farthest from the wiring portion is disposed. The second wirings 60B are bonded to the submount 30 in a region where the protection element 50 is disposed, among the region bisected by the imaginary line L6 in top view. By using this region for bonding the wirings 60, the size of the submount 30 can be reduced, and a compact light-emitting device can be realized.

[0112] In the light emitting device 2, no wiring 60 passes through the imaginary line L4 in a top view.

[0113] In this way, light of multiple colors can be emitted from the light emitting device 2. Furthermore, power can be supplied separately to the first semiconductor laser element 20A and the second semiconductor laser element 20B, making it possible to control the current or voltage appropriate for each.

[0114] <Third embodiment> A light emitting device 3 according to a third embodiment will be described. FIGS. 1, 2, 5, 6, and 9 to 12 are diagrams for explaining an exemplary embodiment of the light emitting device 3. FIG. 1 is a perspective view of the light emitting device 3. FIG. 2 is a top view of the light emitting device 3. FIG. 5 is a top view of the first submount 30A. FIG. 6 is a top view showing the semiconductor laser element 20 and the protection element 50 mounted on the first submount 30A. FIG. 9 is a cross-sectional view taken along the IX-IX line in FIG. 1. FIG. 10 is a top view showing the configuration of each component mounted on the base 10 of the light emitting device 1. FIG. 11 is a top view of the second submount 30B. FIG. 12 is a top view showing the semiconductor laser element 20 and the protection element 50 mounted on the second submount 30B.

[0115] The light emitting device 3 includes a plurality of components. The plurality of components include a base 10, a plurality of semiconductor laser elements 20, a plurality of submounts 30, one or a plurality of reflecting members 40, a plurality of protective elements 50, a plurality of wirings 60, a lid member 70, and an optical member 80. In the light emitting device 3, the plurality of semiconductor laser elements 20 include a first semiconductor laser element 20A and a second semiconductor laser element 20B. Note that the light emitting device 3 may include other components as well.

[0116] The base 10, the semiconductor laser element 20, the submount 30, the reflecting member 40, the protective element 50, the wiring 60, the lid member 70, and the optical member 80 are common to those in the first embodiment, and therefore the explanation of each component is the same as that in the first embodiment. In addition, the first semiconductor laser element 20A and the second semiconductor laser element 20B are common to those in the second embodiment.

[0117] The light emitting device 3 will be described below. The light emitting device 3 has different features from the light emitting device 1 of the first embodiment and the light emitting device 2 of the second embodiment, but also has some common features. Of the details explained about the light emitting device 1 in the first embodiment and the details explained about the light emitting device 2 in the second embodiment, those details that do not cause inconsistencies based on Figures 1, 2, 5, 6, and 9 to 12 also apply to the light emitting device 3.

[0118] (Light-emitting device 3) In the light emitting device 3, the multiple submounts 30 include a first submount 30A and a second submount 30B. The first submount 30A and the second submount 30B differ in the relative arrangement of the second arrangement region 33B with respect to the first arrangement region 33A. The first submount 30A has the second arrangement region 33B provided near one of the two long sides of the upper surface 31 of the submount 30, while the second submount 30B has the second arrangement region 33B provided near the other side.

[0119] The length of the short side of the top surface 31 of the first submount 30A is 95% or more and 105% or less of the length of the short side of the top surface 31 of the second submount 30B. The length of the long side of the top surface 31 of the first submount 30A is 95% or more and 105% or less of the length of the long side of the top surface 31 of the second submount 30B. The first submount 30A and the second submount 30B have the same size and shape.

[0120] In the light emitting device 3, the plurality of semiconductor laser elements 20 include a first semiconductor laser element 20A and a second semiconductor laser element 20B. The plurality of submounts 30 include a first submount 30A on which the first semiconductor laser element 20A is disposed, and a second submount 30B on which the second semiconductor laser element 20B is disposed.

[0121] The first semiconductor laser element 20A, which is farthest from the wiring portion to which the first wiring 60A is bonded, is disposed on the first submount 30A. The second placement region 33B of the first submount 30A is provided at a position close to the longer side of the two sides that is farther from the wiring portion. The distance from the first wiring 60A bonded to the wiring portion and the first submount 30A to the position where the first wiring 60A is bonded to the first submount 30A is shorter than the distance from the wiring portion to the second placement region 33B of the first submount 30A. This arrangement reduces the length of the wiring 60 and improves stability.

[0122] The second semiconductor laser element 20B, which is farthest from the wiring portion to which the second wiring 60B is bonded, is disposed on the second submount 30B. The second placement region 33B of the second submount 30B is provided at a position close to the longer side of the two sides that is farther from the wiring portion. The distance from the second wiring 60B bonded to the wiring portion and the second submount 30B to the position where the second wiring 60B is bonded to the second submount 30B is shorter than the distance from the wiring portion to the second placement region 33B of the second submount 30B. This arrangement reduces the length of the wiring 60 and improves stability.

[0123] Of the multiple first semiconductor laser elements 20A, the first semiconductor laser elements 20A other than the first semiconductor laser element 20A farthest from the wiring portion to which the first wiring 60A is bonded are disposed on the first submount 30A or the second submount 30B. Of the multiple second semiconductor laser elements 20B, the second semiconductor laser elements 20B other than the second semiconductor laser element 20B farthest from the wiring portion to which the second wiring 60B is bonded are disposed on the first submount 30A or the second submount 30B.

[0124] Each of the plurality of first semiconductor laser elements 20A is disposed on a first submount 30A. Each of the plurality of second semiconductor laser elements 20B is disposed on a second submount 30B. By standardizing the submount 30 used depending on the semiconductor laser element 20 in this way, manufacturing becomes easier and productivity can be improved.

[0125] <Fourth embodiment> A light emitting device 4 according to a fourth embodiment will be described. FIGS. 1, 2, 5, 6, 13, and 14 are drawings for explaining an exemplary embodiment of the light emitting device 4. FIG. 1 is a perspective view of the light emitting device 4. FIG. 2 is a top view of the light emitting device 4. FIG. 5 is a top view of the first submount 30A. FIG. 6 is a top view showing a state in which the semiconductor laser element 20 and the protection element 50 are mounted on the first submount 30A. FIG. 13 is a cross-sectional view taken along the XIII-XIII line in FIG. 1. FIG. 14 is a top view showing the configuration of each component mounted on the base 10B of the light emitting device 1.

[0126] The light emitting device 4 includes a plurality of components. The plurality of components include a base 10B, a plurality of semiconductor laser elements 20, a plurality of submounts 30, one or a plurality of reflecting members 40, a plurality of protective elements 50, a plurality of wirings 60, a lid member 70, and an optical member 80. In the light emitting device 4, the plurality of semiconductor laser elements 20 include a first semiconductor laser element 20A and a second semiconductor laser element 20B. In the light emitting device 4, the plurality of submounts 30 include a first submount 30A or a second submount 30B. The light emitting device 4 may include other components.

[0127] The semiconductor laser element 20, submount 30, reflecting member 40, protective element 50, wiring 60, lid member 70, and optical member 80 are common to the first embodiment, and therefore the description of each component is the same as that of the first embodiment. The first semiconductor laser element 20A and the second semiconductor laser element 20B are also common to those in the second embodiment. The first submount 30A and the second submount 30B are also common to those in the third embodiment.

[0128] The base 10B has different characteristics from the base 10 of the first embodiment, but also has some commonalities. Of the contents explained about the base 10 and the contents explained about the submount 30 in the first embodiment, those that do not cause inconsistencies based on Figures 13 and 14 also apply to the base 10B. Below, the different characteristics of the base 10B will be explained.

[0129] (Base 10B) In the base 10B, the first step portion 12C is formed along part or all of the first inner surface 11E and part of the inner surface 11E (hereinafter referred to as the third inner surface) that intersects with the first inner surface 11E. The first step portion 12C can be said to be a step portion 12C that is integrally formed along each of the adjacent first inner surface 11E and third inner surface 11E.

[0130] The first step portion 12C is formed along the entire inner surface 11E extending in the short-side direction of the rectangular outer edge of the base body 10B and along a part of the inner surface 11E extending in the long-side direction of the outer edge, among the adjacent inner surfaces 11E. The first step portion 12C is formed along the inner surface 11E, with a length that is 10% or more and less than 50% of the inner surface 11E extending in the long-side direction.

[0131] In the illustrated light emitting device 4, the first inner surface 11E extends in the direction of the short sides of the rectangular outer edge of the base 10B, and the third inner surface 11E extends in the direction of the long sides. In addition, the base 10B does not have a step portion 12C formed along the inner surface 11E opposite to the third inner surface 11E.

[0132] In the first step portion 12C, wiring patterns 13 are provided in both a portion formed along the inner surface 11E extending in the short side direction of the rectangular outer edge of the base 10B and a portion formed along the inner surface 11E extending in the long side direction.

[0133] The light emitting device 4 will be described below. The light emitting device 4 has different features from the light emitting device 1 of the first embodiment, the light emitting device 2 of the second embodiment, and the light emitting device 3 of the third embodiment, but also has some common features. Of the details explained about the light emitting device 1 in the first embodiment, the light emitting device 2 in the second embodiment, and the light emitting device 3 in the third embodiment, those details that do not cause inconsistencies based on Figures 1, 2, 5, 6, 13, and 14 also apply to the light emitting device 4.

[0134] (Light-emitting device 4) In the light emitting device 4, the plurality of submounts 30 includes a first submount 30A or a second submount 30B. The plurality of submounts 30 also includes a third submount 30C. In the illustrated light emitting device 4, the plurality of submounts 30 include a second submount 30B and a third submount 30C. The second submount 30B may be substituted for the first submount 30A.

[0135] The length of the long side of the top surface 31 of the third submount 30C is smaller than the length of the long side of the top surface 31 of the first submount 30A or the second submount 30B. Hereinafter, the first submount 30A or the second submount 30B will be referred to as the longer submount 30, and the third submount 30C will be referred to as the shorter submount 30 to distinguish them.

[0136] The multiple submounts 30 include multiple longer submounts 30. The multiple submounts 30 include multiple shorter submounts 30. The shorter submounts 30 have a first placement region 33A but do not have a second placement region 33B. In other words, the shorter submounts 30 do not have a second placement region 33B. Therefore, the protection element 50 is not placed on the shorter submounts 30. By not providing the second placement region 33B, the length of the upper surface 31 in the long side direction can be made shorter than that of the longer submounts 30.

[0137] With respect to the length in the long side direction, the longer submount 30 is greater than the shorter submount 30 by 100 μm or more and 600 μm or less. This prevents the base 10 from becoming larger while ensuring an area for arranging the protective element 50 in the longer submount 30, thereby contributing to miniaturization of the light emitting device 1.

[0138] In the light emitting device 4, one of the first semiconductor laser element 20A and the second semiconductor laser element 20B is disposed on the longer submount 30, and the other is disposed on the shorter submount 30. In the light emitting device 4 shown in the figure, the first semiconductor laser element 20A is disposed on the shorter submount 30, and the second semiconductor laser element 20B is disposed on the longer submount 30.

[0139] The shorter submount 30 is arranged on the first step portion 12C side, and the longer submount 30 is arranged on the second step portion 12C side.

[0140] In relation to the portion of the first step portion 12C formed along the third inner side surface 11E, the shorter submount 30 is perpendicular to the third inner side surface 11E in top view and is disposed at a position where an imaginary line L7 passes through this portion of the first step portion 12C. Furthermore, the longer submount 30 is parallel to the third inner side surface 11E in top view and is disposed at a position where an imaginary line L8 passes through this portion of the first step portion 12C.

[0141] The semiconductor laser element 20 mounted on the longer submount 30 is not positioned at a location that passes through the imaginary line L8. The protection element 50 mounted on the longer submount 30 is positioned at a location that passes through the imaginary line L8. This makes it possible to ensure an area on the mounting surface 11D for arranging the protection element 50 without increasing the size of the base 10B.

[0142] The protection elements 50 that protect the semiconductor laser elements 20 arranged on the shorter submounts 30 are arranged on the first step portion 12C. One protection element 50 that protects the semiconductor laser elements 20 arranged on each of the shorter submounts 30 is arranged on the first step portion 12C. There is only one protection element 50 arranged on the first step portion 12C. This allows the number of protection elements 50 used to be reduced compared to when a protection element 50 is arranged on each individual semiconductor laser element 20.

[0143] The multiple wirings 60 bonded to the first step portion 12C include a wiring 60 bonded to the shorter submount 30 located closest to the first inner side surface 11E or the semiconductor laser element 20 located on this submount 30, and a wiring 60 bonded to the shorter submount 30 located farthest from the first inner side surface 11E or the semiconductor laser element 20 located on this submount 30. In the first step portion 12C, the protection element 50 is disposed between these two wirings 60. The former wiring 60 is bonded to the wiring pattern 13 at a portion formed along the first inner side surface 11E of the first step portion 12C, and the latter wiring 60 is bonded to the wiring pattern 13 at a portion formed along the third inner side surface 11E of the first step portion 12C.

[0144] In the light emitting device 4, the number of longer submounts 30 arranged on the mounting surface 11D is greater than the number of shorter submounts 30 arranged on the mounting surface 11D. The number of longer submounts 30 arranged on the mounting surface 11D is three or more.

[0145] When providing a protective element 50 in a one-to-one correspondence with the semiconductor laser element 20, if the protective element 50 is placed in the step portion 12C, the joining of the wiring 60 to the submount 30 becomes complicated. However, if a longer submount 30 is used, the semiconductor laser element 20 and the protective element 50 can be placed on the submount 30, making it easier to join the wiring 60.

[0146] It is considered that the greater the number of semiconductor laser elements 20 connected in series, the greater the significance of protecting each semiconductor laser element 20. On the other hand, if the number of semiconductor laser elements 20 connected in series is not that large, it is also possible to consider protecting them all together with one protection element 50. According to this concept, it can also be considered preferable that the number of shorter submounts 30 arranged on the mounting surface 11D is two or less.

[0147] The distance from the first inner surface 11E to the point farthest from the first inner surface 11E in the portion of the first step portion 12C that is partially provided on the third inner surface 11E is shorter than the distance from the first inner surface 11E to the longer submount 30 that is located closest to the first inner surface 11E. This allows the longer submount 30 to be located without contacting the first step portion 12C.

[0148] In the light emitting device 4, the difference between the length of the longer side of the longer submount 30 and the length of the shorter submount 30 is smaller than the length of the portion of the first step portion 12C formed along the third inner side surface 11E in the direction perpendicular to the third inner side surface 11E. This difference in length is preferably 30% to 90% of the length of the portion of the first step portion 12C formed along the third inner side surface 11E in the direction perpendicular to the third inner side surface 11E. This may make the effect of partially providing the step portion 12C more pronounced.

[0149] Although the above describes various embodiments of the present invention, the light-emitting device according to the present invention is not strictly limited to the light-emitting device of each embodiment. In other words, the present invention can be realized without being limited to the external shape and structure of the light-emitting device disclosed in each embodiment. The present invention can be applied without necessarily including all necessary and sufficient components. For example, if the claims do not recite some of the components of the light-emitting device disclosed in the embodiments, the claims allow for the design freedom of those components by those skilled in the art, such as substitution, omission, modification of shape, and change of material, and specify that the invention described in the claims applies. [Industrial Applicability]

[0150] The light emitting device according to each embodiment can be used in projectors, vehicle headlights, head-mounted displays, lighting, displays, and the like. [Explanation of symbols]

[0151] 1, 2, 3, 4 Light-emitting device 10, 10B base 11A Top 11B Bottom side 11C External surface 11D Mounting surface 11E Inside surface 12C Step 13 Wiring Pattern 20 Semiconductor laser element 20A First semiconductor laser element 20B Second semiconductor laser element 30 Submount 31 Top side 32 Side 32A 1st side 32B 2nd side 33 Placement area 33A 1st placement area 33B 2nd placement area 30A 1st submount 30B Second submount 30C 3rd submount 40 Reflective material 50 Protection element 60 Wiring 60A 1st wiring 60B 2nd wiring 70 Lid member 80 Optical Components

Claims

1. a base having an upper surface, a first wiring portion, and a second wiring portion; a plurality of submounts each having a top surface, a first side surface, a second side surface opposite to the first side surface, and a first arrangement region and a second arrangement region provided on the top surface, the first side surfaces being arranged side by side in a first direction on the top surface of the base, and the length in a second direction perpendicular to the first direction in a top view being greater than the length in the first direction; a plurality of semiconductor laser elements each having a light emitting surface, the semiconductor laser elements being arranged in the first arrangement region of the submount different from each other, with the light emitting surface being closer to the first side surface than the second side surface; a plurality of protection elements, each of which is disposed in the second arrangement region of a different one of the submounts; Multiple wiring and Equipped with the first arrangement region is provided at a position where a virtual line passing through a center of the first side surface and parallel to the second direction passes in a top view, the plurality of semiconductor laser elements include a first semiconductor laser element and a second semiconductor laser element that emit light having different peak wavelengths, and are disposed between the first wiring portion and the second wiring portion when viewed from above; the plurality of wirings include one or more first wirings electrically connected to the first semiconductor laser element, and one or more second wirings electrically connected to the second semiconductor laser element, the one or more first wirings include at least the first wiring bonded to the submount on which the first semiconductor laser element is disposed and the first wiring portion, the one or more second wirings include at least the second wirings joined to the submount on which the second semiconductor laser element is disposed and the second wiring portion, the plurality of protection elements include a first protection element disposed on the submount on which the first semiconductor laser element is disposed, and a second protection element disposed on the submount on which the second semiconductor laser element is disposed, the first protection element is disposed at a position such that a center of a length in the first direction is spaced apart in the first direction from the imaginary line based on the submount on which the first semiconductor laser element is disposed, a center of the length in the first direction of the second protection element is disposed at a position away in the first direction from the imaginary line based on the submount on which the second semiconductor laser element is disposed.

2. a base having an upper surface, a first wiring portion, and a second wiring portion; a plurality of submounts each having a top surface, a first side surface, a second side surface opposite to the first side surface, and a first arrangement region and a second arrangement region provided on the top surface, the first side surfaces being arranged side by side in a first direction on the top surface of the base, and the length in a second direction perpendicular to the first direction in a top view being greater than the length in the first direction; a plurality of semiconductor laser elements each having a light emitting surface, the semiconductor laser elements being arranged in the first arrangement region of the submount different from each other, with the light emitting surface being closer to the first side surface than the second side surface; a plurality of protection elements, each of which is disposed in the second arrangement region of a different one of the submounts; Multiple wiring and Equipped with the first arrangement region is provided at a position where a virtual line passing through a center of the first side surface and parallel to the second direction passes in a top view, the plurality of semiconductor laser elements include a first semiconductor laser element and a second semiconductor laser element that emit light having different peak wavelengths, and are disposed between the first wiring portion and the second wiring portion when viewed from above; the plurality of wirings include one or more first wirings electrically connected to the first semiconductor laser element, and one or more second wirings electrically connected to the second semiconductor laser element, the one or more first wirings include at least the first wiring bonded to the submount on which the first semiconductor laser element is disposed and the first wiring portion, the one or more second wirings include at least the second wirings joined to the submount on which the second semiconductor laser element is disposed and the second wiring portion, the plurality of protection elements include a first protection element disposed on the submount on which the first semiconductor laser element is disposed, and a second protection element disposed on the submount on which the second semiconductor laser element is disposed, the first protection element is disposed at a position such that a center of a length in the first direction is spaced apart in the first direction from the imaginary line based on the submount on which the first semiconductor laser element is disposed, a light-emitting device, wherein the center of the length in the first direction of the second protection element is disposed at a position away from the imaginary line based on the submount on which the second semiconductor laser element is disposed, in a direction opposite to the first direction.

3. The light emitting device according to claim 1 , wherein the plurality of submounts are arranged at intervals of 50 μm or more and 300 μm or less in the first direction.

4. 4. The light-emitting device according to claim 1, wherein the length in the first direction of at least one of the plurality of submounts is 2.5 times or more and 5 times or less the smallest value of the spacing between adjacent submounts in the plurality of submounts.

5. 5. The light emitting device according to claim 1, wherein in the submount on which the first semiconductor laser element is arranged, the first arrangement region and the second arrangement region are separated from each other or are a single arrangement region that is partially connected.

6. 6. The light emitting device according to claim 1, wherein in the submount on which the second semiconductor laser element is arranged, the first arrangement region and the second arrangement region are separated from each other or are a single arrangement region that is partially connected.

7. The light emitting device according to claim 1 , wherein the plurality of submounts includes five or more submounts.

8. 8. The light emitting device according to claim 1, wherein the plurality of semiconductor laser elements emit light whose fast axis direction is perpendicular to the upper surface of the base body and whose divergence angle in the slow axis direction is 20 degrees or less.

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