Light emitting device

Abstract

To provide a light emitting device which hardly blocks an emitted laser beam.SOLUTION: The light emitting device includes a base portion, a frame portion surrounding the base portion and having a step portion, a light source portion disposed on an upper surface of the base portion so as to be surrounded by the frame portion and configured to emit laser light in a normal direction of the upper surface of the base portion, a light-transmissive member disposed on an upper surface of the step portion and configured to transmit the laser light, and a reflective member disposed on an upper surface of the light-transmissive member and configured to reflect the laser light transmitted through the light-transmissive member. A portion of the frame part is provided with a recess that penetrates from an inner surface to an outer surface of the frame part and opens on an upper surface side of the frame part, and an optical axis of the laser light reflected by the reflecting member overlaps with the recess in a top view.SELECTED DRAWING: Figure 8

Description

[Technical Field]

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

[0002] A light emitting device is known that includes a substrate having a mounting surface, a semiconductor laser element supported by the mounting surface, a first mirror member supported by the mounting surface and having a first reflecting surface facing obliquely upward, a cover having an opposing surface facing the mounting surface of the substrate and an upper surface located opposite the opposing surface, and positioned above the semiconductor laser element and the first mirror member, and a second mirror member supported by the upper surface of the cover and having a second reflecting surface (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-018650 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a light emitting device that is less likely to block emitted laser light. [Means for solving the problem]

[0005] A light emitting device according to one embodiment of the present disclosure includes a base, a frame surrounding the base and having a stepped portion, a light source disposed on an upper surface of the base and surrounded by the frame, and emitting laser light in a direction normal to the upper surface of the base, a translucent member disposed on the upper surface of the stepped portion and transmitting the laser light, and a reflecting member disposed on the upper surface of the translucent member and reflecting the laser light that passes through the translucent member, wherein a recess is provided in a part of the frame, penetrating from the inner surface to the outer surface of the frame and opening to the upper surface side of the frame, and the optical axis of the laser light reflected by the reflecting member overlaps with the recess in a top view. [Effects of the Invention]

[0006] According to an embodiment of the present disclosure, it is possible to provide a light emitting device that does not easily block emitted laser light. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view illustrating a light emitting device according to a first embodiment. [Figure 2] 1 is an exploded perspective view illustrating a light emitting device according to a first embodiment. [Figure 3] FIG. 1 is a top view illustrating a light emitting device according to a first embodiment. [Figure 4] FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3. [Figure 5] FIG. 2 is a top view of the light emitting device according to the first embodiment with the lid removed. [Figure 6] FIG. 2 is a top view of a frame portion that constitutes the light emitting device according to the first embodiment. [Figure 7] 1 is a partially enlarged cross-sectional view of the light emitting device according to the first embodiment. [Figure 8] FIG. 2 is a partially enlarged top view of the light emitting device according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, a description of an embodiment of the invention will be given with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms including these terms) will be used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not unduly limit the technical scope of the present invention. For example, when the term "upper surface" is used, it does not necessarily mean that the invention must always be used facing upward. Furthermore, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or components.

[0009] Furthermore, in this disclosure, polygons such as triangles and quadrilaterals are referred to as polygons, including shapes in which the corners of the polygons have been processed, such as by rounding, chamfering, corner removal, or rounding. 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 polygon as a base are included in the interpretation of "polygon" described in this disclosure.

[0010] The same applies to words that represent 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 have been 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."

[0011] Furthermore, the embodiments shown below are intended to exemplify light-emitting devices and the like embodying the technical concepts of the present invention, and are not intended to limit the present invention thereto. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, the content described in one embodiment may also be applicable to other embodiments and modified examples. Furthermore, the size and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, to avoid overly complex drawings, schematic diagrams may be used in which some elements are omitted, or end views may be used as cross-sectional views showing only the cut surface.

[0012] <Embodiment> The light emitting device according to the present disclosure includes a base 210, a frame 220 that surrounds the base 210 and has a step 225, a light source unit 230 that is disposed on an upper surface 210a of the base 210 and surrounded by the frame 220, and that emits laser light in a normal direction to the upper surface 210a of the base 210, a light-transmitting member 240 that is disposed on an upper surface 225a of the step 225 and transmits the laser light, and a light-transmitting member 240 and a reflecting member 250 disposed on an upper surface 240a and reflecting laser light passing through the light-transmitting member 240, wherein a recess 220x is provided in a part of the frame portion 220, penetrating from an inner surface 220c to an outer surface 220d of the frame portion 220 and opening on the upper surface 220a side of the frame portion 220, and when viewed from above, the optical axis of the laser light reflected by the reflecting member 250 overlaps with the recess 220x.

[0013] [Light-emitting device 200] As an example of a light emitting device according to the present disclosure, a light emitting device 200 will be described. FIG. 1 is a perspective view illustrating a light emitting device according to a first embodiment. FIG. 2 is an exploded perspective view illustrating a light emitting device according to the first embodiment. FIG. 3 is a top view illustrating a light emitting device according to the first embodiment. FIG. 4 is a cross-sectional view taken along the IV-IV line in FIG. 3. FIG. 5 is a top view of the light emitting device according to the first embodiment with the lid removed. FIG. 6 is a top view of a frame constituting the light emitting device according to the first embodiment. Note that in the cross-sectional view shown in FIG. 4, some metal films are omitted from the illustration.

[0014] In each drawing, for reference, mutually orthogonal X-, Y-, and Z-axes are shown as necessary. The direction parallel to the X-axis is called the X-direction, the direction parallel to the Y-axis is called the Y-direction, and the direction parallel to the Z-axis is called the Z-direction. In the X-direction, the direction in which the arrow points is called the +X-direction, and the direction opposite the +X-direction is called the -X-direction. In the Y-direction, the direction in which the arrow points is called the +Y-direction, and the direction opposite the +Y-direction is called the -Y-direction. In the Z-direction, the direction in which the arrow points is called the +Z-direction, and the direction opposite the +Z-direction is called the -Z-direction. However, these do not limit the orientation of the light-emitting device when in use, and the orientation of the light-emitting device is arbitrary. Viewing an object from the +Y-direction toward the -Y-direction is called top view.

[0015] The light emitting device 200 according to the first embodiment includes a base 210, a frame 220, a light source 230, a light-transmitting member 240, and a reflecting member 250. In the example shown in FIGS. 1 to 6, the light emitting device 200 further includes a submount 261, a lens support 264, wiring 265, and a protective element 266.

[0016] Each component of the light emitting device 200 will be described.

[0017] (base 210) The base 210 has an upper surface 210a and a lower surface 210b. The upper surface 210a and the lower surface 210b are, for example, flat surfaces. The upper surface 210a and the lower surface 210b are, for example, parallel to each other. Here, when describing "parallel," a difference of ±5° is allowed. The base 210 has a rectangular outer shape when viewed from above. This rectangle may have long and short sides. Note that the outer shape of the base 210 when viewed from above does not have to be rectangular. Unless specifically mentioned to exclude squares, the term "rectangle" may include squares.

[0018] The base 210 can be formed, for example, with a metal as its main material. Examples of the metal that can be used include copper and copper alloys. The base 210 may also be formed primarily from a material other than metal, such as ceramics. A metal film may be provided on the upper surface 210a of the base 210.

[0019] (frame portion 220) The frame portion 220 has an upper surface 220a, a lower surface 220b, one or more inner surfaces 220c, and one or more outer surfaces 220d. The frame portion 220 has, for example, a rectangular frame shape when viewed from above. The one or more inner surfaces 220c of the frame portion 220 are connected to the upper surface 220a and extend downward from the upper surface 220a. The one or more outer surfaces 220d of the frame portion 220 are connected to the upper surface 220a and the lower surface 220b of the frame portion 220. The frame portion 220 surrounds the light source unit 230 when viewed from above.

[0020] Metal films 221 and 222 that are electrically insulated from each other may be provided on the upper surface 220a of the frame portion 220. The metal films 221 and 222 are, for example, spaced apart from each other and arranged side by side in the X direction. The metal films 221 and 222 are, for example, rectangular and have approximately the same area. A metal film 223 may be provided on the upper surface 220a of the frame portion 220. The metal film 223 has, for example, a roughly rectangular frame shape. The metal film 223 surrounds the light source portion 230 in top view. The metal films 221, 222, and 223 may have a layered structure such as Ni / Au or Ti / Pt / Au.

[0021] The frame portion 220 has a step portion 225 with an upper surface 225a that is located above the upper surface 210a of the base portion 210 and below the upper surface 220a of the frame portion 220. The step portion 225 has an inner surface that is connected to the upper surface 225a and extends downward. The upper surface 225a is connected to one or more inner surfaces 220c of the frame portion 220. The upper surface 225a may be parallel to the upper surface 210a of the base portion 210, for example. The inner surface of the step portion 225 is connected to the upper surface 210a of the base portion 210, for example. The step portion 225 may be provided along the inner surface 220c of the frame portion 220 in a top view.

[0022] A metal film 226 may be provided on the upper surface 225a of the step portion 225. The metal film 226 has, for example, a rectangular frame shape. The metal film 226 surrounds the light source portion 230 in top view. The metal film 226 can be used when joining the frame portion 220 to the light-transmitting member 240, for example, via a metal adhesive. The metal film 226 may be made of, for example, the same material as the metal film 221.

[0023] The step portion 225 may further have a lower surface 225b that is connected to the inner surface of the step portion 225. The lower surface 225b may be a plane parallel to the upper surface 225a. The lower surface 225b is located higher than the lower surface 220b of the frame portion 220. The lower surface 225b of the step portion 225 is joined to the upper surface 210a of the base portion 210. In the example shown, the frame portion 220 further has a side surface that is connected to the lower surface 225b and extends downward. This side surface is connected to the lower surface 220b of the frame portion 220.

[0024] The frame 220 may further include a second step portion 227 having an upper surface 227a that is located above the upper surface 210a of the base 210 and below the upper surface 225a of the step portion 225. The second step portion 227 has an inner surface that is connected to the upper surface 227a and extends downward. The upper surface 227a is connected to the inner surface of the step portion 225. The upper surface 227a may be parallel to the upper surface 210a of the base 210, for example. The inner surface of the second step portion 227 is connected to the upper surface 210a of the base 210, for example. A portion of the inner surface of the second step portion 227 may be connected to the inner surface of the step portion 225.

[0025] The second step portion 227 may be provided along part or all of the inner surface of the step portion 225 in a top view. In the illustrated example, two second step portions 227 facing each other in the X direction are provided along the inner surface of the upper surface 225a of the step portion 225 in a top view. A metal film 228 may be provided on the upper surface 227a of the second step portion 227 located in the -X direction. Furthermore, a metal film 229 may be provided on the upper surface 227a of the second step portion 227 located in the +X direction. The metal film 228 may be electrically connected to the metal film 221, for example, via a via wiring. The metal film 229 may be electrically connected to the metal film 222, for example, via a via wiring. The metal films 228 and 229 may be formed using, for example, the same material as the metal film 221.

[0026] A recess 220x is provided in a portion of the frame 220, penetrating from the inner surface 220c to the outer surface 220d of the frame 220 and opening toward the upper surface 220a of the frame 220. The frame 220 has a bottom surface 220p and opposing wall surfaces 220q and 220r that define the recess 220x. The bottom surface 220p may be a plane parallel to the upper surface 225a. The bottom surface 220p may be located on the same plane as the upper surface 225a. The wall surfaces 220q and 220r may be planes perpendicular to the bottom surface 220p. The wall surfaces 220q and 220r may be parallel to each other. The distance between the bottom surface 220p of the recess 220x and the upper surface 220a of the frame 220 is, for example, 500 μm or more.

[0027] The frame 220 may include two pairs of opposing side walls, namely, side walls 220W1 and 220W2, and side walls 220W3 and 220W4. The side walls 220W1 and 220W2 face each other, and the side walls 220W3 and 220W4 face each other. The recess 220x is preferably provided in only one of the side walls 220W1, 220W2, 220W3, and 220W4. In particular, the recess 220x is preferably provided in the side wall 220W1, which is located in the traveling direction of the laser light LB reflected by the reflecting member 250 in a top view. This configuration reduces the number of side walls that are difficult to grip when gripping the frame 220 with a jig or the like to only one, thereby increasing the number of side walls that can be gripped, making it easier to handle the frame 220 during manufacturing processes, etc. Furthermore, the recess 220x can reduce the possibility that the laser light LB will be blocked.

[0028] The side wall 220W2 facing the side wall 220W1 on which the recess 220x is provided has a notch that does not penetrate from the inner surface 220c to the outer surface 220d of the frame 220. The notch is provided on the edge of the side wall 220W2 that is closest to the -Z side in top view. One possible method for manufacturing the frame 220 is to line up multiple frame portions 220 in the X and Z directions, form them into an integrated unit, and then separate them. In such a case, the provision of the notch makes it easier to separate two frame portions 220 that are formed adjacent to each other in the Z direction. In top view, the width of the notch in the X direction is the same as the width of the recess 220x in the X direction.

[0029] The frame 220 can be formed, for example, using a material different from that of the base 210 as a main material. Examples of main materials for forming the frame 220 include ceramics. For example, aluminum nitride, silicon nitride, aluminum oxide, or silicon carbide can be used as the ceramic.

[0030] (Light source section 230) The light source section 230 includes a semiconductor laser element 231, a lens 232, and a second reflecting member 233. The light source section 230 does not necessarily have to include the lens 232 and / or the second reflecting member 233.

[0031] [Semiconductor laser element 231] In the illustrated example of light emitting device 200, one semiconductor laser element 231 is mounted. Light emitting device 200 may be mounted with a plurality of semiconductor laser elements. Semiconductor laser element 231 has, for example, a rectangular outer shape when viewed from above. A side surface including one of the two short sides of the rectangle serves as a light emission surface for light emitted from semiconductor laser element 231. The upper and lower surfaces of semiconductor laser element 231 have areas larger than that of the light emission surface.

[0032] A metal film may be provided on the upper surface of the semiconductor laser element 231. This metal film may be provided with wiring or the like for electrical connection with other members, for example.

[0033] The light (laser light) emitted from the semiconductor laser element 231 has a spread and forms an elliptical far-field pattern (hereinafter referred to as "FFP") on a plane parallel to the light emitting surface. Here, FFP refers to the shape and light intensity distribution of the emitted light at a position away from the light emitting surface.

[0034] The direction passing through the major axis of the ellipse is defined as the fast axis direction of the FFP, and the direction passing through the minor axis of the ellipse is defined as the slow axis direction of the FFP, based on the elliptical light emitted from the semiconductor laser element 231. The fast axis direction of the FFP in the semiconductor laser element 231 can coincide with the stacking direction in which multiple semiconductor layers including the active layer of the semiconductor laser element 231 are stacked.

[0035] Also, based on the light intensity distribution of the FFP of the semiconductor laser element 231, 1 / e 2 The light having an intensity of 1 / e or more is called the main light. 2The angle corresponding to the intensity of is called the divergence angle. The divergence angle in the fast axis direction of the FFP is larger than the divergence angle in the slow axis direction of the FFP. Note that e is the base of the natural logarithm.

[0036] Furthermore, the light passing through the center of the elliptical shape of the FFP, in other words, the light with the 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. Furthermore, the optical path of the light traveling through the center of the elliptical shape of the FFP is referred to as the optical axis of that light.

[0037] As the semiconductor laser element 231, for example, a semiconductor laser element that emits blue light can be used. "A semiconductor laser element that emits blue light" refers to the use of a semiconductor laser element that emits light with an emission peak wavelength in the range of 405 nm to 494 nm. Furthermore, it is preferable to use a semiconductor laser element that emits light with a peak wavelength of 430 nm to 480 nm as the semiconductor laser element 231. An example of such a semiconductor laser element 231 is a semiconductor laser element that includes a nitride semiconductor. As the nitride semiconductor, for example, GaN, InGaN, AlGaN, or AlInGaN can be used.

[0038] It should be noted that the emission peak of the light emitted from the semiconductor laser element 231 is not limited to this. For example, the light emitted from the semiconductor laser element 231 may be visible light including green light, red light, and purple light having wavelengths outside the above-mentioned wavelength range, ultraviolet light, or infrared light, in addition to blue light.

[0039] [Lens 232] The lens 232 has an incident surface where light enters, a lower surface connected to the incident surface, and a cylindrical surface from which light entering from the incident surface exits. The cylindrical surface is connected to the lower surface. The incident surface faces the cylindrical surface. The incident surface and the lower surface of the lens 232 are, for example, flat. The incident surface is, for example, perpendicular to the lower surface. The cylindrical surface is a convex curved surface that functions as a lens and has a curvature in the YZ plane. The lens 232 can be, for example, a cylindrical lens having a uniform cross-sectional shape in the X direction.

[0040] Lens 232 may be made of at least one light-transmitting material selected from the group consisting of glass, silicon, quartz, synthetic quartz, sapphire, and transparent ceramics. Lens 232 may have a portion that functions as a lens, as well as a portion that is used for attachment to other components.

[0041] (Second reflecting member 233) The second reflecting member 233 has a lower surface, a reflecting surface 233a that reflects light, and a plurality of side surfaces connected to the reflecting surface 233a and the lower surface. In the illustrated light emitting device 200, the lower surface, the reflecting surface 233a, and the plurality of side surfaces are all flat. In a side view, the second reflecting member 233 may be triangular. In particular, in a side view, the second reflecting member 233 may be triangular with chamfered corners.

[0042] The plurality of side surfaces includes two side surfaces that face each other across the reflecting surface 233a. The plurality of side surfaces also includes one side surface that connects the two side surfaces that face each other across the reflecting surface 233a. The two side surfaces that face each other across the reflecting surface 233a may have the same area.

[0043] In the illustrated light emitting device 200, the reflecting surface 233a is rectangular. The reflecting surface 233a is inclined with respect to the lower surface of the second reflecting member 233. The inclination angle of the reflecting surface 233a with respect to the lower surface of the second reflecting member 233 is, for example, 45°, but is not limited to this angle and may be, for example, between 30° and 60°. Note that when a specific angle of inclination is stated, a deviation of ±5° from the specific angle is included for manufactured products, taking into account manufacturing precision.

[0044] The lower surface and the reflecting surface 233a may each be a curved surface, or may be a mixture of flat and curved surfaces. Also, the reflecting surface 233a does not have to be rectangular as long as it can reflect incident light in a desired direction.

[0045] The second reflecting member 233 may be mainly made of glass, metal, or the like, which forms its outer shape. The main material is preferably a heat-resistant material, such as glass, such as quartz or BK7 (borosilicate glass), metal, such as aluminum, or Si. The reflecting surface 233a may be provided with, for example, a metal or a dielectric multilayer film. Examples of metals include Ag and Al. Examples of materials for the dielectric multilayer film include Ta2O5 / SiO2, TiO2 / SiO2, and Nb2O5 / SiO2.

[0046] (Translucent member 240) The light-transmitting member 240 has an upper surface 240a, a lower surface 240b, and one or more side surfaces connected to the upper surface 240a and the lower surface 240b. The one or more side surfaces connect the outer edge of the upper surface 240a to the outer edge of the lower surface 240b. The light-transmitting member 240 is, for example, a rectangular parallelepiped or a cube. In this case, both the upper surface 240a and the lower surface 240b of the light-transmitting member 240 are rectangular, and the light-transmitting member 240 has four rectangular side surfaces.

[0047] The light-transmitting member 240 is not limited to a rectangular parallelepiped or a cube. That is, the light-transmitting member 240 is not limited to a rectangular shape when viewed from above, and can have any shape such as a circle, an ellipse, or a polygon.

[0048] The light-transmitting member 240 is formed of, for example, a light-transmitting material. An example of the light-transmitting material is sapphire. Sapphire is a material with relatively high transmittance and relatively high strength. In addition to sapphire, other light-transmitting materials such as quartz, silicon carbide, or glass may also be used. The light-transmitting member 240 has a light-transmitting region 240t that transmits light. In a top view, the light-transmitting region 240t has, for example, a rectangular shape, but is not limited to this shape. The shape of the light-transmitting region 240t may be, for example, a circular or elliptical shape. In the illustrated example, a light-shielding film 245 is provided on the lower surface 240b of the light-transmitting member 240, excluding the region through which light passes, thereby defining the light-transmitting region 240t. That is, the light-shielding film 245 is provided on the lower surface 240b of the light-transmitting member 240, surrounding the light-transmitting region 240t. The light-shielding film 245 may be provided around the light-transmitting region 240t on the upper surface 240a of the light-transmitting member 240. The light-transmitting region 240t preferably transmits 70% or more of the laser light.

[0049] The light-shielding film 245 reduces the risk that stray light other than laser light generated inside the light-emitting device 200 will leak out of the light-emitting device 200. Furthermore, when a bonding material that is cured by irradiation with ultraviolet light or visible light is used to bond the reflective member 250 to the upper surface of the light-transmitting member 240, the light-shielding film 245 reduces the risk that ultraviolet light or visible light irradiated onto the bonding material will reach the semiconductor laser element 231 when the bonding material is cured. The light-shielding film 245 also reduces the risk that the laser light LB emitted to the outside of the light-emitting device 200 will return toward the light-emitting device 200 due to factors such as diffuse reflection (hereinafter referred to as returned light) and reach the semiconductor laser element 231. Reducing irradiation of the semiconductor laser element 231 by ultraviolet light or visible light or returned light can reduce damage to the semiconductor laser element 231.

[0050] The light-shielding film 245 is preferably provided on the entire lower surface of the light-transmitting member 240 except for the light-transmitting region 240t. The light-shielding film 245 thus provided further reduces the risk of the stray light leaking to the outside of the light-emitting device 200 and the risk of the ultraviolet light or visible light or the returned light reaching the semiconductor laser element 231. The light-shielding film 245 can be formed from, for example, the same material as the metal film 221.

[0051] (Reflective member 250) The reflecting member 250 has a lower surface, a reflecting surface 250a that reflects incident light, and a plurality of side surfaces connected to the reflecting surface 250a and the lower surface. In the illustrated light emitting device 200, the lower surface, the reflecting surface 250a, and the plurality of side surfaces are all flat surfaces.

[0052] The plurality of side surfaces includes two side surfaces that face each other across the reflecting surface 250a. The plurality of side surfaces also includes one side surface that connects the two side surfaces that face each other across the reflecting surface 250a. The two side surfaces that face each other across the reflecting surface 250a may have the same area.

[0053] In the illustrated light emitting device 200, the reflective surface 250a is rectangular. The reflective surface 250a is inclined with respect to the lower surface of the reflective member 250. The inclination angle of the reflective surface 250a with respect to the lower surface of the reflective member 250 is, for example, 45°, but is not limited to this angle and may be, for example, between 30° and 60°.

[0054] The lower surface and the reflective surface 250a may each be a curved surface, or may be a mixture of flat and curved surfaces. Also, the reflective surface 250a does not have to be rectangular as long as it can reflect incident light in a desired direction.

[0055] The main material forming the outer shape of reflecting member 250 can be the same as that of second reflecting member 233. Also, reflecting surface 250a can be formed using, for example, the same material as that of reflecting surface 233a of second reflecting member 233.

[0056] (Submount 261) The submount 261 is, for example, rectangular parallelepiped-shaped and has a bottom surface, a top surface, and one or more side surfaces. A part or all of the submount 261 may be made of at least one material selected from the group consisting of AlN, SiC, alumina, diamond, CuW, Cu, a Cu / AlN / Cu stacked structure, and a metal matrix composite (MMC). The MMC may include diamond and at least one material selected from the group consisting of Cu, Ag, and Al. Alternatively, a part or all of the submount 261 may be made of other common materials.

[0057] The thermal conductivity of the submount 261 can be, for example, 10 [W / m·K] or more and 2500 [W / m·K] or less. With such thermal conductivity, the submount 261 can efficiently transfer the heat generated from the semiconductor laser element 231 during operation to the base 210. The thermal expansion coefficient of the submount 261 can be, for example, 2×10 -6 [1 / K] or more 2×10 -5 [1 / K] or less. Such a thermal expansion coefficient can reduce the risk of the submount 261 being deformed by heat applied when the semiconductor laser element 231 is bonded onto the submount 261 with a bonding material. The size of the submount 261 in the X direction is, for example, 1 mm or more and 3 mm or less, the size in the Y direction is, for example, 0.1 mm or more and 0.5 mm or less, and the size in the Z direction is, for example, 1 mm or more and 6 mm or less.

[0058] A metal film having a thickness of, for example, 0.5 μm or more and 10 μm or less may be formed on the upper and lower surfaces of the submount 261 by, for example, plating. In the illustrated example, a metal film 262 is formed on the upper surface of the submount 261, and a metal film 263 is formed on the lower surface. The metal film 262 is useful when bonding the submount 261 and the semiconductor laser element 231 with a bonding material and when supplying power to the semiconductor laser element 231. The metal film 263 is useful when bonding the submount 261 and the upper surface 210a of the base 210 with a bonding material. Providing the metal films 262 and 263 can improve the heat dissipation properties of the submount 261. For example, the same material as the metal film 221 can be used for the metal films 262 and 263.

[0059] (lens support part 264) The lens support 264 is useful for fixing the lens 232 to another member. The lens support 264 may be made of, for example, a ceramic selected from the group consisting of AlN, SiN, SiC, and alumina, or may be made of at least one alloy selected from the group consisting of Kovar and CuW. The lens support 264 may also be made of, for example, Si.

[0060] (Wiring 265) The wiring 265 is made of a conductor having a linear shape with joints at both ends. In other words, the wiring 265 has joints at both ends of the linear portion that are joined to other components. The wiring 265 is used for electrical connection between two components. For example, a metal wire can be used as the wiring 265. Examples of metals include gold, aluminum, silver, copper, and tungsten.

[0061] (protection element 266) The protection element 266 is a component for protecting a specific element such as the semiconductor laser element 231. For example, the protection element 266 is a component for preventing an excessive current from flowing through a specific element such as the semiconductor laser element 231 and damaging it. For example, a Zener diode made of Si can be used as the protection element 266. Furthermore, for example, the protection element 266 may be a component for measuring temperature to prevent the specific element from failing due to the temperature environment. A thermistor can be used as such a temperature measurement element. It is preferable to place the temperature measurement element near the light emission surface of the semiconductor laser element 231.

[0062] (Light emitting device 200) Next, the light emitting device 200 will be described. Hereinafter, a case where the light source section 230 is made up of a submount 261, a semiconductor laser element 231, a lens 232, and a second reflecting member 233 will be described as an example.

[0063] The submount 261 is disposed on the upper surface 210a of the base 210. More specifically, the submount 261 is bonded to the upper surface 210a of the base 210 via, for example, an adhesive on the lower surface side on which the metal film 263 is provided. The semiconductor laser element 231 is placed directly or indirectly on the upper surface of the submount 261 disposed on the upper surface 210a of the base 210. For example, the semiconductor laser element 231 is bonded to the metal film 262 provided on the upper surface of the submount 261 via an adhesive. An example of the adhesive used for this bonding is AuSn.

[0064] The semiconductor laser element 231 is disposed so that its light emitting surface faces the same direction as one of the side surfaces of the submount 261. Furthermore, the light emitting surface of the semiconductor laser element 231 may be parallel or perpendicular to, for example, one of the inner side surfaces 220c or one of the outer side surfaces 220d of the frame portion 220. The semiconductor laser element 231 emits light that travels in the Z direction. The light emitted from the semiconductor laser element 231 is, for example, blue light. Note that the light emitted from the semiconductor laser element 231 is not limited to blue light.

[0065] The semiconductor laser element 231 is electrically connected to a metal film 229 provided on an upper surface 227a of the second step portion 227 located in the -X direction via a wiring 265. One end of the wiring 265 is joined to the metal film provided on the upper surface of the semiconductor laser element 231. The light emitting device 200 further includes, for example, a plurality of wirings 265. The plurality of wirings 265 includes a wiring 265 having one end joined to a metal film 228 provided on an upper surface 227a of the second step portion 227 located in the +X direction and the other end joined to a metal film 262 provided on the submount 261. With this connection, power can be supplied to the semiconductor laser element 231 by applying a voltage between the metal films 221 and 222 provided on the upper surface 220a of the frame portion 220.

[0066] It is preferable that second step portion 227 is provided at least at a position facing two side surfaces of semiconductor laser element 231. This makes it possible to shorten wiring 265 that electrically connects metal film 228 provided on upper surface 227a of second step portion 227 to metal film 262 provided on submount 261, and metal film 229 provided on upper surface 227a of second step portion 227 to a metal film provided on the upper surface of semiconductor laser element 231. Shortening wiring 265 contributes to improving the electrical characteristics of light emitting device 200 and reducing the size of light emitting device 200. Furthermore, current can be easily supplied to semiconductor laser element 231 via metal films 228 and 228.

[0067] The lens 232 is fixed directly or indirectly to the submount 261. In the illustrated example, the lens 232 is fixed to a lens support 264 provided on the upper surface of the submount 261. The lens support 264 is provided on the upper surface of the submount 261 and supports the lens 232. By providing the lens support 264 in this way, the lens 232 can be easily fixed to the submount 261. By fixing the lens 232 to the submount 261, the semiconductor laser element 231 and the lens 232 are fixed to the same member, and therefore, the relative positional relationship between the semiconductor laser element 231 and the lens 232 can be made less likely to shift.

[0068] Lens 232 is supported by lens support portion 264 so that its incident surface faces the light emission surface of semiconductor laser element 231 and its cylindrical surface faces reflecting surface 233a of second reflecting member 233. The focal point of lens 232 substantially coincides with the center of the light emitting point of the light emission surface of semiconductor laser element 231. Lens 232 collimates laser light LB, which is emitted in the +Z direction from the light emission surface of semiconductor laser element 231, in the YZ plane.

[0069] The second reflecting member 233 is disposed on the upper surface 210a of the base 210. For example, the second reflecting member 233 is disposed on a metal film disposed directly below. The lower surface of the second reflecting member 233 is located lower than the lower surface of the lens 232. It is also preferable that the lowest part of the reflecting surface 233a is located lower than the lower surface of the lens 232. This structure makes it easier for more of the light emitted from the cylindrical surface of the lens 232 to reach the reflecting surface 233a. The second reflecting member 233 has a metal film on its lower surface, and this metal film and the upper surface 210a of the base 210 are bonded together, for example, via an adhesive. Examples of adhesives used for this bonding include AuSn and Au paste.

[0070] Second reflecting member 233 is disposed on the side of lens 232 on upper surface 210a of base 210. Second reflecting member 233 is disposed on the opposite side of semiconductor laser element 231 in the Z direction, with lens 232 sandwiched therebetween. Reflecting surface 233a of second reflecting member 233 faces the direction of the cylindrical surface of lens 232. Reflecting surface 233a of second reflecting member 233 reflects laser light LB, which is emitted from the light emission surface of the semiconductor laser element and passes through lens 232, in the normal direction (+Y direction) of upper surface 210a of base 210.

[0071] Although the above description has been given of the case where light source unit 230 is composed of submount 261, semiconductor laser element 231, lens 232, and second reflecting member 233, light source unit 230 may have other configurations. For example, light source unit 230 may be a vertical cavity surface emitting laser element provided on top surface 210a of base 210 directly or via submount 261. Since the laser light emitted from the vertical cavity surface emitting laser element is in the normal direction (+Y direction) of top surface 210a of base 210, when a vertical cavity surface emitting laser element is used as light source unit 230, there is no need to provide second reflecting member 233 separately, which saves on components.

[0072] The protective element 266 may be disposed on, for example, the upper surface of the submount 261. In the illustrated example, one electrode of the protective element 266 is electrically connected to a metal film 229 provided on an upper surface 227a of the second step portion 227 located in the −X direction via a wiring 265. The other electrode of the protective element 266 is electrically connected to a metal film 262 provided on the upper surface of the submount 261.

[0073] An outer periphery of the upper surface 210a of the base 210 is joined to a lower surface 225b of the step portion 225 of the frame portion 220. The frame portion 220 surrounds the base 210. In the illustrated example, in a top view, the frame portion 220 surrounds the light source portion 230, the submount 261, and the lens support portion 264 that are located on the base 210. That is, the light source portion 230 is disposed on the upper surface 210a of the base 210 while being surrounded by the frame portion 220, and emits laser light LB in a normal direction to the upper surface 210a of the base 210.

[0074] The light-transmitting member 240 is disposed on the upper surface 225a of the step portion 225 of the frame portion 220 and transmits the laser light LB. Specifically, the light-transmitting member 240 is supported by the upper surface 225a of the step portion 225 of the frame portion 220 and is disposed above the semiconductor laser element 231 surrounded by the frame portion 220. The outer periphery of the lower surface 240b of the light-transmitting member 240 is bonded to the upper surface 225a of the step portion 225 of the frame portion 220, for example. For example, a metal film provided on the outer periphery of the lower surface 240b of the light-transmitting member 240 and a metal film 226 provided on the upper surface 225a of the step portion 225 of the frame portion 220 are bonded via AuSn or the like. The light-shielding film 245 may be used as the metal film when bonding the light-transmitting member 240 and the upper surface 225a of the step portion 225. This eliminates the need to separately provide a member for blocking light and a member for joining. By disposing the light-transmitting member 240 on the upper surface 225a of the step portion 225 of the frame portion 220 in this manner, even if the light-transmitting member 240 shifts during or after installation, the movement of the light-transmitting member 240 is restricted by the frame portion 220, and therefore, the shifting of the light-transmitting member 240 can be reduced.

[0075] In the normal direction of the upper surface 210a of the base 210, it is preferable that the distance L1 from the upper surface 225a of the step portion 225 to the upper surface 220a of the frame portion 220 be longer than the distance L2 from the upper surface 225a of the step portion 225 to the upper surface 240a of the light-transmitting member 240. As a result, the upper surface 240a of the light-transmitting member 240 is disposed at a position recessed from the upper surface 220a of the frame portion 220. With this structure, when the light-emitting device 200 is handled by suction, the contact position between the suction device and the light-emitting device 200 is the upper surface 220a of the frame portion 220 rather than the upper surface 240a of the light-transmitting member 240, thereby preventing scratches and contamination on the light-transmitting member 240.

[0076] The lower surface 240b of the light-transmitting member 240 is joined to the upper surface 225a of the step portion 225 of the frame portion 220, thereby forming a space sealed by the base portion 210, the frame portion 220, and the light-transmitting member 240. The light source portion 230 can be disposed in this sealed space. This space may be a hermetically sealed space. By hermetically sealing this space, for example, it is possible to reduce the risk of organic matter or the like collecting on the light emission surface of the semiconductor laser element 231 that constitutes the light source portion 230.

[0077] In the normal direction of the upper surface 210a of the base 210, the distance L3 from the upper surface 210a of the base 210 to the bottom surface 220p of the recess 220x is preferably the same as the distance L4 from the upper surface 210a of the base 210 to the upper surface 225a of the step portion 225. This makes it easier to manufacture the frame portion 220, thereby reducing the manufacturing cost of the light emitting device 200. Here, "the distances L3 and L4 being the same" means that the difference between them is less than 50 μm.

[0078] The reflecting member 250 is disposed on the upper surface 240a of the light-transmitting member 240, for example, via a bonding member. The reflecting surface 250a of the reflecting member 250 at least partially overlaps with the light-transmitting region 240t of the light-transmitting member 240 and the reflecting surface 233a of the second reflecting member 233, as viewed from above. The bonding member that fixes the reflecting member 250 can be, for example, a thermosetting resin that is hardened by heating, or a photocurable resin that is hardened by irradiation with ultraviolet light or visible light.

[0079] The reflecting member 250 reflects the laser light LB that passes through the light-transmitting member 240. Specifically, the laser light LB reflected in the +Y direction by the reflecting surface 233a of the second reflecting member 233 passes through the light-transmitting region 240t of the light-transmitting member 240 and reaches the reflecting surface 250a of the reflecting member 250. The laser light LB that has reached the reflecting surface 250a of the reflecting member 250 is reflected by the reflecting surface 250a, and its traveling direction changes to the +Z direction.

[0080] Active alignment may be performed before curing the resin when forming the bonding member that fixes the reflecting member 250. That is, when forming the bonding member, the position and orientation of the reflecting member 250 may be adjusted so that the reflecting surface 250a changes the traveling direction of the laser light LB to the +Z direction while the laser light LB is being emitted from the semiconductor laser element 231, and then the bonding member may be cured.

[0081] FIG. 7 is a partially enlarged cross-sectional view of the light emitting device according to the first embodiment, showing a part of the cross section taken along the line IV-IV in FIG.

[0082] 7, the solid arrow indicates the optical axis when the traveling direction of the laser beam LB reflected by the reflecting surface 250a is the +Z direction, and the two-dot chain arrow indicates the optical axis when the traveling direction of the laser beam LB reflected by the reflecting surface 250a is diagonally downward from the +Z direction.

[0083] For example, due to manufacturing errors when assembling the components that make up the light emitting device 200, fluctuations in the optical axis due to long-term use, changes in the optical axis when the optical axis is changed to a desired position by active alignment of the reflecting member 250, etc., it may occur that the direction of travel of the laser light LB reflected by the reflecting surface 250a becomes diagonally downward from the +Z direction.

[0084] 7, in light emitting device 200, recesses 220x are provided in frame 220. As a result, even when the traveling direction of laser light LB reflected by reflective surface 250a is obliquely downward relative to the +Z direction, the light passes through recesses 220x and is therefore less likely to be blocked by frame 220. As a result, the amount of light emitted from light emitting device 200 can be increased.

[0085] Furthermore, when the light-transmitting member 240 is provided on the upper surface 225a of the step portion 225, the height of the light-transmitting member 240 and the reflecting member 250 from the upper surface 210a of the base 210 is lower than when the light-transmitting member 240 is provided on the upper surface 220a of the frame portion 220. In this case, the distance between the optical axis of the laser light reflected by the reflecting member 250 and the upper surface 220a of the frame portion 220 becomes shorter, and when the traveling direction of the laser light LB is obliquely downward with respect to the +Z direction, the laser light LB is more likely to be blocked by the frame portion 220. By providing the recesses 220x, even when the traveling direction of the laser light LB reflected by the reflecting surface 250a is obliquely downward with respect to the +Z direction, the laser light LB passes through the recesses 220x and is less likely to be blocked by the frame portion 220. As a result, the amount of light emitted from the light-emitting device 200 can be increased.

[0086] Furthermore, in the light emitting device 200, by providing the recess 220x in the frame portion 220, light that is reflected by the reflecting surface 250a of the reflecting member 250 and travels downward, out of the main light emitted from the semiconductor laser element 231, is less likely to be blocked by the frame portion 220. As a result, the utilization efficiency of the main light emitted from the semiconductor laser element 231 is improved, and the amount of light emitted from the light emitting device 200 can be increased.

[0087] The recess 220x preferably has a depth such that the light that travels most downward among the main light emitted from the semiconductor laser element 231 does not strike the bottom surface 220p of the recess 220x. This allows the frame 220 not to block the light that travels most downward among the main light emitted from the semiconductor laser element 231 after being reflected by the reflecting surface 250a of the reflecting member 250. As a result, the utilization efficiency of the main light emitted from the semiconductor laser element 231 is further improved, and the amount of light emitted from the light emitting device 200 can be further increased.

[0088] Fig. 8 is a partially enlarged top view of the light emitting device according to the first embodiment. In the laser light LB shown in Fig. 8, the solid arrow indicates the optical axis, and the two dashed arrows indicate the range in which the main light emitted from the semiconductor laser element 231 spreads.

[0089] 8, in a top view, the optical axis of the laser light LB reflected by the reflecting surface 250a of the reflecting member 250 overlaps with the recess 220x. This makes it difficult for light traveling in the left-right direction, among the main light emitted from the semiconductor laser element 231, to hit the wall surfaces 220q and 220r of the recess 220x. As a result, the utilization efficiency of the main light emitted from the semiconductor laser element 231 is improved, and the amount of light emitted from the light emitting device 200 can be increased.

[0090] In FIG. 8 , the distance L5 between the opposing wall surfaces 220q and 220r is preferably greater than the width L6 of the laser beam LB overlapping the bottom surface 220p of the recess 220x in a top view. This prevents light traveling in the left-right direction from hitting the wall surfaces 220q and 220r of the recess 220x, among the main light beams emitted from the semiconductor laser element 231. As a result, the utilization efficiency of the main light beam emitted from the semiconductor laser element 231 is further improved, and the amount of light emitted from the light-emitting device 200 can be further increased. The distance L5 can be, for example, 200 μm or more. Note that a portion of the light beam that is not the main beam of light emitted from the semiconductor laser element 231 may hit the wall surfaces 220q and 220r of the recess 220x and be reflected, potentially becoming stray light. To reduce the effects of stray light, the wall surfaces 220q and 220r of the recess 220x are preferably made of a material with low optical reflectivity.

[0091] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0092] In addition to the above-described embodiments, the following supplementary notes are also disclosed. (Appendix 1) A base and a frame portion surrounding the base portion and having a stepped portion; a light source unit that is disposed on the upper surface of the base and is surrounded by the frame unit, and that emits laser light in a normal direction to the upper surface of the base; a light-transmitting member disposed on an upper surface of the step portion and transmitting the laser light; a reflecting member disposed on an upper surface of the light-transmitting member and configured to reflect the laser light transmitted through the light-transmitting member, a recessed portion is provided in a part of the frame portion, the recessed portion penetrating from the inner surface to the outer surface of the frame portion and opening to the upper surface side of the frame portion; The light emitting device, wherein an optical axis of the laser light reflected by the reflecting member overlaps with the recess in a top view. (Appendix 2) 2. The light emitting device according to claim 1, wherein the distance from the upper surface of the step portion to the upper surface of the frame portion in the normal direction is longer than the distance from the upper surface of the step portion to the upper surface of the translucent member. (Appendix 3) the frame portion has a bottom surface and opposing wall surfaces that define the recessed portion, 3. The light emitting device according to claim 1, wherein the distance between the opposing wall surfaces is greater than the width of the laser light that overlaps with the bottom surface when viewed from above. (Appendix 4) 4. The light emitting device according to claim 3, wherein the distance from the top surface of the base to the bottom surface in the normal direction is the same as the distance from the top surface of the base to the top surface of the step portion. (Appendix 5) The frame portion includes two pairs of opposing sidewall portions, 5. The light emitting device according to claim 1, wherein the recess is provided in only one of the sidewalls. (Appendix 6) 6. The light emitting device according to any one of claims 1 to 5, wherein the light source section includes a semiconductor laser element and a second reflecting member that reflects laser light emitted from a light emitting surface of the semiconductor laser element in the normal direction. (Appendix 7) the frame portion has a second step portion having an upper surface located above the upper surface of the base portion and below the upper surface of the step portion, a metal film is provided on an upper surface of the second step portion; 7. The light emitting device according to claim 6, wherein the semiconductor laser element is electrically connected to the metal film via wiring. (Appendix 8) 8. The light emitting device according to claim 7, wherein the second step portion is provided at least at a position facing two side surfaces of the semiconductor laser element. (Appendix 9) a hermetically sealed space is formed by the base, the frame, and the light-transmitting member; 9. The light emitting device according to claim 1, wherein the light source unit is disposed in the space. [Explanation of symbols]

[0093] 200 Light-emitting device 210 base 210a top side 210b Bottom side 220 Frame 220a top side 220b Bottom side 220c inner surface 220d outer surface 220p bottom 220q, 220r wall 220x recess 220W1,220W2,220W3,220W4 Side wall part 221,222,223,226,228,229 Metallic film 225 Step 225a Top 225b Bottom side 227 Second step 227a Top side 230 Light source section 231 Semiconductor laser element 232 Lens 233 Second reflecting member 233a Reflective surface 240 Translucent material 240a top side 240b Bottom side 240t light transmission area 245 Light-shielding film 250 Reflective material 250a reflective surface 261 Submount 262,263 Metallic film 264 Lens support 265 Wiring 266 Protection Element

Claims

1. A base and a frame portion surrounding the base portion and having a stepped portion; a light source unit that is disposed on the upper surface of the base and is surrounded by the frame unit, and that emits laser light in a normal direction to the upper surface of the base; a light-transmitting member disposed on an upper surface of the step portion and transmitting the laser light; a reflecting member disposed on an upper surface of the light-transmitting member and configured to reflect the laser light transmitted through the light-transmitting member, a recessed portion is provided in a part of the frame portion, the recessed portion penetrating from the inner surface to the outer surface of the frame portion and opening to the upper surface side of the frame portion; The light emitting device, wherein an optical axis of the laser light reflected by the reflecting member overlaps with the recess in a top view.

2. The light emitting device according to claim 1 , wherein a distance from an upper surface of the step portion to an upper surface of the frame portion in the normal direction is longer than a distance from the upper surface of the step portion to an upper surface of the translucent member.

3. the frame portion has a bottom surface and opposing wall surfaces that define the recessed portion, The light emitting device according to claim 1 , wherein the distance between the opposing wall surfaces is greater than a width of the laser light that overlaps with the bottom surface when viewed from above.

4. The light emitting device according to claim 3 , wherein the distance from the top surface of the base to the bottom surface in the normal direction is the same as the distance from the top surface of the base to the top surface of the step portion.

5. the frame portion includes two pairs of opposing sidewall portions, The light emitting device according to claim 1 , wherein the recess is provided in only one of the sidewalls.

6. 3. The light emitting device according to claim 1, wherein the light source section includes a semiconductor laser element and a second reflecting member that reflects laser light emitted from a light emitting surface of the semiconductor laser element in the normal direction.

7. the frame portion has a second step portion having an upper surface located above the upper surface of the base portion and below the upper surface of the step portion, a metal film is provided on an upper surface of the second step portion; The light emitting device according to claim 6 , wherein the semiconductor laser element is electrically connected to the metal film via wiring.

8. The light emitting device according to claim 7 , wherein the second step portion is provided at least at a position facing two side surfaces of the semiconductor laser element.

9. a hermetically sealed space is formed by the base, the frame, and the light-transmitting member; The light emitting device according to claim 1 , wherein the light source unit is disposed in the space.

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