Light-emitting device

Abstract

To make a light-emitting device thinner.SOLUTION: A light-emitting device includes a base, a submount arranged on an upper surface of the base, a semiconductor laser element arranged on the upper surface of the submount and emitting light from an emission end surface, and a lens fixed directly or indirectly to the submount and having a cylindrical surface, and the lens includes a lens portion having an entrance surface for the light and a lower surface connected to the entrance surface, the entrance surface facing the emission end surface of the semiconductor laser element, and includes a generatrix of the lens portion that is farthest from the emission end surface in the normal direction of the emission end surface, and the lens portion is symmetrical with respect to a virtual plane parallel to the lower surface within a range of a predetermined distance in the normal direction of the virtual plane, and the lens portion exists longer than the predetermined distance in the direction opposite to the lower surface from the virtual plane, the lower surface of the lens portion is located at the predetermined distance from the virtual plane, and a gap exists between the lower surface of the lens portion and the upper surface of the base.SELECTED DRAWING: Figure 10

Description

Technical Field

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

Background Art

[0002] A light-emitting device including a semiconductor laser element is used in various applications such as a processing device, a projector, and a lighting fixture. A typical example of such a light-emitting device includes a semiconductor laser element, a submount that supports the semiconductor laser element, and a lens into which light emitted from the semiconductor laser element is incident (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure aims to reduce the thickness of a light-emitting device.

Means for Solving the Problems

[0005] A light-emitting device according to an embodiment of the present disclosure includes a base, a submount disposed on the upper surface of the base, a semiconductor laser element disposed on the upper surface of the submount and emitting light from an emission end face, and a lens directly or indirectly fixed to the submount and having a cylindrical surface. The lens includes an incident surface of the light and a lower surface connected to the incident surface. The incident surface includes a lens portion facing the emission end face of the semiconductor laser element. Among the generatrices of the lens portion, the generatrix farthest from the emission end face in the normal direction of the emission end face is included. With respect to a virtual plane parallel to the lower surface, the lens portion is symmetric with respect to the virtual plane within a range of a predetermined distance in the normal direction of the virtual plane. In a direction opposite to the lower surface from the virtual plane, the lens portion exists longer than the predetermined distance. The lower surface of the lens portion is at a position of the predetermined distance from the virtual plane, and there is a gap between the lower surface of the lens portion and the upper surface of the base.

Advantages of the Invention

[0006] According to an embodiment of the present disclosure, the light-emitting device can be thinned.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the following description, terms indicating a specific direction or position (for example, "up", "down", and other terms including those terms) are used as necessary. However, the use of those terms is for facilitating the understanding of the invention with reference to the drawings, and the technical scope of the present invention is not excessively limited by the meanings of those terms. For example, when it is described as "upper surface", the invention does not always have to be used so as to face upward. Also, parts denoted by the same reference numerals appearing in a plurality of drawings indicate the same or equivalent parts or members.

[0009] In the present disclosure, with respect to polygons such as triangles and quadrilaterals, those having a shape obtained by performing processing such as rounding, chamfering, corner cutting, and rounding at the corners of the polygon are also included in the polygons. Also, not limited to the corners (ends of the sides), those having a shape obtained by performing processing on the middle part of the sides are also referred to as polygons. That is, a shape obtained by performing partial processing while leaving the polygon as a base is included in the interpretation of the "polygon" described in the present disclosure.

[0010] Moreover, not limited to polygons, the same applies to terms representing specific shapes such as trapezoids, circles, and unevenness. The same also applies when dealing with each side forming the shape. That is, even if processing is performed on a corner or the middle part of a certain side, the processed part is included in the interpretation of the "side". When distinguishing a "polygon" or "side" without partial processing from the processed shape, "strict" is added, and for example, it is described as "strict quadrilateral" or the like.

[0011] Furthermore, the following embodiments exemplify a light-emitting device or the like for embodying the technical idea of the present invention, and do not limit the present invention thereto. Also, the dimensions, materials, shapes, relative arrangements, etc. of the components described below are not intended to limit the scope of the present invention only thereto without specific description, but are intended to be illustrative. Also, the content described in one embodiment is applicable to other embodiments and modifications. Also, the sizes and positional relationships of the members shown in the drawings may be exaggerated for clarity of explanation. Furthermore, in order to avoid excessive complexity of the drawings, a schematic diagram omitting the illustration of some elements may be used, or an end view showing only the cut surface as a cross-sectional view may be used.

[0012] <First Embodiment> FIG. 1 is a perspective view exemplifying a light-emitting device according to the first embodiment. FIG. 2 is an exploded perspective view exemplifying the light-emitting device according to the first embodiment. FIG. 3 is a perspective view of the light-emitting device shown in FIG. 1 with the frame portion and the lid portion removed. FIG. 4 is a perspective view for explaining the attachment of the lens according to the present disclosure. FIG. 5 is a top view of the light-emitting device shown in FIG. 1 with the lid portion removed. FIG. 6 is a top view exemplifying the light-emitting device according to the first embodiment. FIG. 7 is a cross-sectional view taken along the VII-VII cross-sectional line of FIG. 6. FIG. 8 is a side view of the lens according to the present disclosure.

[0013] In each drawing, for reference, the X-axis, Y-axis, and Z-axis orthogonal to each other are shown as necessary. The direction parallel to the X-axis is referred to as the X direction. Also, in the X direction, the direction in which the arrow is pointing is referred to as the +X direction, and the direction opposite to the +X direction is referred to as the -X direction. In the Y direction, the direction in which the arrow is pointing is referred to as the +Y direction, and the direction opposite to the +Y direction is referred to as the -Y direction. In the Z direction, the direction in which the arrow is pointing is referred to as the +Z direction, and the direction opposite to the +Z direction is referred to as the -Z direction. However, these do not limit the orientation of the light-emitting device during use, and the orientation of the light-emitting device is arbitrary.

[0014] The light-emitting device 200 according to the first embodiment includes, as a minimum configuration, a base 210, a submount 220, a semiconductor laser element 230, and a lens 240. In the examples shown in FIGS. 1 to 7, the light-emitting device 200 further includes a lens support portion 250, a reflection member 260, a frame portion 310, a lid portion 320, and a reflection member 330.

[0015] Each component of the light-emitting device 200 will be described.

[0016] (Base 210) As shown in FIG. 3, the base 210 has an upper surface 210a and a lower surface 210b. The upper surface 210a is, for example, a flat surface. In the example shown in FIG. 3, the lower surface 210b is a flat surface. The upper surface 210a and the lower surface 210b are, for example, parallel. Here, when described as "parallel", a difference of ±5 degrees is allowed. The base 210 has a rectangular outer shape when viewed from above. This rectangle may be a rectangle having a long side and a short side. Note that the outer shape of the base 210 when viewed from above does not have to be rectangular. Unless otherwise excluded from a square, the rectangle may include a square.

[0017] The base 210 can be formed, for example, mainly of metal. For example, copper, a copper alloy, or the like can be used. Note that the base 210 may be formed of a main material other than metal, for example, ceramics. A metal film may be provided on the upper surface 210a of the base 210.

[0018] (Submount 220) As shown in FIG. 3, the submount 220 is configured, for example, in the shape of a rectangular parallelepiped and has a bottom surface, a top surface, and one or more side surfaces. Part or all of the submount 220 can be formed from at least one selected from the group consisting of, for example, AlN, SiC, alumina, CuW, Cu, a laminated structure of Cu / AlN / Cu, and a metal matrix composite (MMC). The MMC contains, for example, at least one selected from the group consisting of Cu, Ag, or Al and diamond. Alternatively, part or all of the submount 220 may be formed from other common materials.

[0019] The thermal conductivity of the submount 220 can be, for example, 10 [W / m·K] or more and 2500 [W / m·K] or less. With such a thermal conductivity, the submount 220 can efficiently transfer the heat generated from the semiconductor laser element 230 during driving to the base 210. The coefficient of thermal expansion of the submount 220 is, for example, 2×10 -6 [1 / K] or more and 2×10 -5 [1 / K] or less. With such a coefficient of thermal expansion, the possibility of the submount 220 being deformed by the heat applied when the semiconductor laser element 230 is bonded to the submount 220 with a bonding material can be reduced. The size of the submount 220 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.

[0020] On the upper and lower surfaces of the submount 220, a metal film having a thickness of, for example, 0.5 μm or more and 10 μm or less may be formed by, for example, plating. In the examples of FIGS. 1 to 7, a metal film 223 is formed on the upper surface of the submount 220, and a metal film 225 is formed on the lower surface. The metal film 223 is useful when bonding the submount 220 and the semiconductor laser element 230 with a bonding material and when supplying power to the semiconductor laser element 230. The metal film 225 is useful when bonding the submount 220 and the upper surface 210a of the base 210 with a bonding material. By providing the metal film 223 and the metal film 225, the heat dissipation property of the submount 220 can be improved.

[0021] (Semiconductor laser element 230) In the illustrated example of the light-emitting device 200, one semiconductor laser element 230 is mounted. The light-emitting device 200 may mount a plurality of semiconductor laser elements. The semiconductor laser element 230 has, for example, a rectangular outer shape in a top view. Also, a side surface intersecting one of the two short sides of the rectangle serves as an emission end face 230a of the light emitted from the semiconductor laser element 230. Also, the upper and lower surfaces of the semiconductor laser element 230 have a larger area than the emission end face 230a.

[0022] A metal film may be provided on the upper surface of the semiconductor laser element 230. This metal film is provided with, for example, wiring for electrical connection to other members.

[0023] The light (laser light) emitted from the semiconductor laser element 230 has a spread and forms an elliptical far-field pattern (hereinafter referred to as "FFP") on a plane parallel to the emission end face 230a. Here, the FFP indicates the shape and light intensity distribution of the emitted light at a position away from the emission end face.

[0024] Based on the elliptical light emitted from the semiconductor laser element 230, 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. The fast axis direction of the FFP in the semiconductor laser element 230 may coincide with the stacking direction in which a plurality of semiconductor layers including the active layer of the semiconductor laser element 230 are stacked.

[0025] Also, based on the light intensity distribution of the FFP of the semiconductor laser element 230, light having an intensity of 1 / e or more with respect to the peak intensity value is defined as the main light. Also, in this light intensity distribution, the angle corresponding to the intensity of 1 / e 2 is defined as 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. Here, e is the base of the natural logarithm. 2 In addition, the light passing through the center of the ellipse of the FFP, in other words, the light having the peak intensity in the light intensity distribution of the FFP, is defined as the light traveling along the optical axis or the light passing through the optical axis. Also, the optical path of the light traveling through the center of the ellipse of the FFP is defined as the optical axis of that light.

[0026] As the semiconductor laser element 230, a semiconductor laser element that emits blue light can be used. The "semiconductor laser element that emits blue light" refers to using a semiconductor laser element in which the emission peak wavelength of the emitted light is in the range of 405 nm to 494 nm. Also, as the semiconductor laser element 230, it is preferable to use a semiconductor laser element in which the peak wavelength of the emitted light is 430 nm to 480 nm. Examples of such a semiconductor laser element 230 include a semiconductor laser element including a nitride semiconductor. As the nitride semiconductor, for example, GaN, InGaN, AlGaN, or AlInGaN can be used.

[0027] As the semiconductor laser element 230, a semiconductor laser element that emits blue light can be used. The "semiconductor laser element that emits blue light" refers to using a semiconductor laser element in which the emission peak wavelength of the emitted light is in the range of 405 nm to 494 nm. Also, as the semiconductor laser element 230, it is preferable to use a semiconductor laser element in which the peak wavelength of the emitted light is 430 nm to 480 nm. Examples of such a semiconductor laser element 230 include a semiconductor laser element including a nitride semiconductor. As the nitride semiconductor, for example, GaN, InGaN, AlGaN, or AlInGaN can be used.

[0028] Note that the emission peak of the light emitted from the semiconductor laser element 230 is not limited to this. For example, the light emitted from the semiconductor laser element 230 can be visible light including green light, red light, and purple light having wavelengths outside the above-described wavelength range, ultraviolet light, and infrared light, in addition to blue light.

[0029] (Lens 240) As shown in FIG. 8, the lens 240 has a lens portion 241 with a minimal configuration. The lens portion 241 includes an incident surface 241a on which the light emitted from the semiconductor laser element 230 is incident, a lower surface 241b connected to the incident surface 241a, and a cylindrical surface 241c that emits the light incident from the incident surface 241a. The cylindrical surface 241c is connected to the lower surface 241b.

[0030] The incident surface 241a and the lower surface 241b are, for example, flat surfaces. The incident surface 241a is, for example, perpendicular to the lower surface 241b. The cylindrical surface 241c is a convex curved surface that functions as a lens and has a curvature in the YZ plane. The lens portion 241 can be, for example, a cylindrical lens having a uniform cross-sectional shape in the X direction.

[0031] In the example shown in FIG. 8, the lens 240 further includes an extension portion 242 that extends from the lens portion 241 to the side opposite to the lower surface 241b. By including the extension portion 242 in the lens 240, the joining with the lens support portion 250 becomes easy. The extension portion 242 includes a first surface 242a that is continuous with the incident surface 241a and is located in the same plane as the incident surface 241a, a second surface 242b that is continuous with the cylindrical surface 241c, and a third surface 242c that connects the first surface 242a and the second surface 242b. In the example shown in FIG. 8, the second surface 242b is a flat surface and is parallel to the first surface 242a. Also, the third surface 242c is a flat surface and is parallel to the lower surface 241b of the lens portion 241. Note that the second surface 242b and the third surface 242c are not limited to this form.

[0032] The lens 240 can be formed of at least one light-transmissive material selected from the group consisting of, for example, glass, silicon, quartz, synthetic quartz, sapphire, and transparent ceramics. The lens portion 241 and the extension portion 242 may be integrally formed or joined separately, but from the viewpoint of improving the mechanical strength of the lens 240, it is preferably integrally formed.

[0033] FIG. 9 is a cross-sectional view of the lens according to the comparative example. As shown in FIG. 9, the lens 240x according to the comparative example is different from the lens 240 in that the lens portion 241 is replaced by the lens portion 243, and the extension portion 242 is the same as the lens 240.

[0034] The lens portion 243 includes an incident surface 243a on which the light emitted from the semiconductor laser element 230 is incident, a lower surface 243b connected to the incident surface 243a, and a cylindrical surface 243c that emits the light incident from the incident surface 243a. The cylindrical surface 243c is connected to the lower surface 243b.

[0035] The incident surface 243a is a flat surface similar to the incident surface 241a. In the lens 240 and the lens 240x, when the Y-direction positions of the third surface 242c of the extension portion 242 are aligned, the lower end of the incident surface 243a is located in the -Y direction relative to the lower end of the incident surface 241a. The cylindrical surface 243c is a convex curved surface that functions as a lens and has the same curvature as the cylindrical surface 241c in the YZ plane. In the lens 240 and the lens 240x, when the Y-direction positions of the third surface 242c of the extension portion 242 are aligned, the lower end of the cylindrical surface 243c is located in the -Y direction relative to the lower end of the cylindrical surface 241c. The lower end of the cylindrical surface 243c is located, for example, on the extension line EL of the second surface 242b of the extension portion 242 in a cross-sectional view.

[0036] The virtual line VL indicates the position of the lower surface 241b of the lens 240. In the lens 240x, the shape in the +Y direction relative to the virtual line VL is the same as that of the lens 240. The lens 240x has a shape in which the portion on the -Y side of the virtual line VL of the lens portion 243 is increased with respect to the lens 240. In other words, the lens 240 has a shape in which the portion on the -Y side of the virtual line VL of the lens 240x is removed, and the length in the Y direction is shorter than that of the lens 240x.

[0037] (Lens support portion 250) As shown in FIG. 4, the lens support portion 250 has two columnar portions 251 and a connecting portion 252 located between the two columnar portions 251 and connecting the two columnar portions 251. The lens support portion 250 may be formed of, for example, ceramics selected from the group consisting of AlN, SiN, SiC, and alumina, or may be formed of at least one alloy selected from the group consisting of kovar and CuW. Further, the lens support portion 250 may be formed of, for example, Si.

[0038] (Reflection member 260) The reflection member 260 includes a lower surface, a reflection surface 260a that reflects light emitted from the columnar surface 241c of the lens portion 241, and a plurality of side surfaces that intersect the reflection surface 260a and the lower surface. In the illustrated light emitting device 200, the lower surface, the reflection surface 260a, and the plurality of side surfaces are each a flat surface. In side view, the reflection member 260 may be triangular. In particular, in side view, the reflection member 260 may be a triangular shape with chamfered corners.

[0039] The plurality of side surfaces include two side surfaces facing each other with the reflection surface 260a interposed therebetween. The plurality of side surfaces also include one side surface that intersects the two side surfaces facing each other with the reflection surface 260a interposed therebetween. The two side surfaces facing each other with the reflection surface 260a interposed therebetween may have the same area.

[0040] In the illustrated light-emitting device 200, the reflecting surface 260a is rectangular. The reflecting surface 260a is inclined with respect to the lower surface of the reflecting member 260. The inclination angle of the reflecting surface 260a with respect to the lower surface of the reflecting member 260 is, for example, 45 degrees, but is not limited to this angle, and may be, for example, 30° or more and 60° or less. When describing the specific angle of the inclination angle, considering the manufacturing accuracy, for manufactured products, it shall include a difference of ±5 degrees from the specific angle.

[0041] Note that the lower surface and the reflecting surface 260a may each be a curved surface, or a plane and a curved surface may be mixed. Also, the reflecting surface 260a does not have to be rectangular as long as it can reflect the incident light in a desired direction.

[0042] For the reflecting member 260, glass, metal, etc. can be used as the main material forming its outer shape. The main material is preferably a heat-resistant material. For example, glass such as quartz or BK7 (borosilicate glass), metal such as aluminum, or Si can be used. Also, for the reflecting surface 260a, for example, a metal or a dielectric multilayer film may be provided. Examples of the metal include Ag, Al, etc. Examples of the materials for the dielectric multilayer film include Ta2O5 / SiO2, TiO2 / SiO2, Nb2O5 / SiO2, etc.

[0043] (Wiring 280) The wiring 280 is composed of a conductor having a linear shape with both ends as joints. In other words, the wiring 280 has joints for joining to other components at both ends of the linear portion. The wiring 280 is used for electrical connection between two components. As the wiring 280, for example, a metal wire can be used. Examples of the metal include gold, aluminum, silver, copper, tungsten, etc.

[0044] (Frame portion 310) The frame portion 310 has an upper surface 310a, a lower surface 310b, one or more inner surfaces, and one or more outer surfaces. The frame portion 310 is, for example, in a rectangular frame shape when viewed from above. One or more inner surfaces of the frame portion 310 intersect the upper surface 310a and extend downward from the upper surface. One or more outer surfaces of the frame portion 310 intersect the upper surface 310a and the lower surface 310b of the frame portion 310.

[0045] On the upper surface 310a of the frame portion 310, a metal film 311 and a metal film 312 that is spaced apart from the metal film 311 and surrounds the metal film 311 can be provided. Each of the metal films 311 and 312 has, for example, a substantially rectangular frame shape. The metal films 311 and 312 surround the submount 220, the semiconductor laser element 230, the lens 240, the lens support portion 250, and the reflecting member 260 when viewed from above. The metal film 311 can be used when joining the frame portion 310 to the lid portion 320 via, for example, a metal adhesive. The metal film 312 can reduce the possibility that the metal adhesive for joining the lid portion 320 flows out beyond the metal film 312.

[0046] On the upper surface 310a of the frame portion 310, metal films 313 and 314 that are electrically insulated from each other in the -Z direction further than the metal film 312 can be provided. The metal film 313 and the metal film 314 are, for example, arranged side by side in the X direction while being spaced apart from each other. The metal films 313 and 314 are, for example, rectangular with substantially the same area. For the metal films 311, 312, 313, and 314, for example, Ni / Au, Ti / Pt / Au, etc. can be used.

[0047] The frame portion 310 may further have a stepped portion 315 having an upper surface 315a that is located above the upper surface 210a of the base portion 210 and below the upper surface 310a of the frame portion 310. The stepped portion 315 further has an inner surface that intersects the upper surface 315a and extends downward. The upper surface 315a intersects one or more inner surfaces of the frame portion 310. The upper surface 315a can be, for example, parallel to the upper surface 210a of the base portion 210. The inner surface of the stepped portion 315 intersects, for example, the upper surface 210a of the base portion 210. The inner surface of the stepped portion 315 is connected to, for example, the inner surface of the frame portion 310. The stepped portion 315 can be provided along a part or all of the inner surface of the frame portion 310 when viewed from above.

[0048] On the upper surface 315a of the stepped portion 315, metal films 316 and 317 can be provided. For the metal films 316 and 317, for example, the same material as the metal film 311 can be used. The metal film 316 can be electrically connected to the metal film 313, for example, via a via wiring. The metal film 317 can be electrically connected to the metal film 314, for example, via a via wiring.

[0049] The stepped portion 315 may further have a lower surface 315b that intersects the inner surface of the stepped portion 315. The lower surface 315b can be a plane parallel to the upper surface 315a. The lower surface 315b is located above the lower surface 310b of the frame portion 310. The lower surface 315b of the stepped portion 315 is joined to the upper surface 210a of the base portion 210. In the illustrated example, the frame portion 310 intersects the lower surface 315b and further has a side surface that extends downward. This side surface intersects the lower surface 310b of the frame portion 310.

[0050] The frame portion 310 can be formed mainly of a material different from that of the base portion 210, for example. An example of the main material forming the frame portion 310 is ceramics. For example, as the ceramics, aluminum nitride, silicon nitride, aluminum oxide, or silicon carbide can be used.

[0051] (Cover portion 320) The cover portion 320 has an upper surface 320a, a lower surface 320b, and one or more side surfaces that intersect the upper surface 320a and the lower surface 320b. The one or more side surfaces connect the outer edge of the upper surface 320a and the outer edge of the lower surface 320b. The cover portion 320 is, for example, a rectangular parallelepiped or a cube. In this case, both the upper surface 320a and the lower surface 320b of the cover portion 320 are rectangular, and the cover portion 320 has four rectangular side surfaces.

[0052] Note that the cover portion 320 is not limited to a rectangular parallelepiped or a cube. That is, the cover portion 320 is not limited to a rectangle in a top view, and can have any shape such as a circle, an ellipse, or a polygon.

[0053] The cover portion 320 has a light transmission region 320t that transmits light. The light transmission region 320t constitutes at least a part of the upper surface 320a and the lower surface 320b of the cover portion 320. The light transmission region 320t has, for example, a rectangular shape, but is not limited to this shape. The light transmission region 320t of the cover portion 320 can be formed, for example, using sapphire as the main material. Sapphire is a material with a relatively high transmittance and relatively high strength. In addition to sapphire, for the main material of the light transmission region 320t of the cover portion 320, a light-transmissive material such as quartz, silicon carbide, or glass may be used. The portion of the cover portion 320 other than the light transmission region 320t may be integrally formed with the light transmission region 320t using the same material as the light transmission region 320t. It is preferable that the light transmission region 320t transmits 70% or more of the laser light LB.

[0054] In the illustrated example, the cover portion 320 has a light-shielding film 322 around the light transmission region 320t on the lower surface 320b. The light transmission region 320t has a rectangular shape, but is not limited to this shape. The shape of the light transmission region 320t may be, for example, circular or elliptical.

[0055] The light-shielding film 322 reduces the risk of stray light other than the laser light generated inside the light-emitting device 200 leaking to the outside of the light-emitting device 200. When the light-shielding film 322 is further formed by curing the resin layer 340 shown in FIG. 7 by irradiation with ultraviolet light or visible light, the light-shielding film 322 reduces the risk of ultraviolet light or visible light reaching the semiconductor laser element 230. The light-shielding film 322 further reduces the risk that the laser light LB emitted to the outside of the light-emitting device 200 becomes light (hereinafter referred to as return light) that returns in the direction of the light-emitting device 200 due to factors such as diffuse reflection and reaches the semiconductor laser element 230. If irradiation by ultraviolet light, visible light, or return light can be reduced, the semiconductor laser element 230 is less likely to be damaged.

[0056] The light-shielding film 322 is preferably provided over the entire area of the lower surface 320b other than the light-transmitting region 320t. The light-shielding film 322 provided in this manner further reduces the risk that the above-described stray light leaks outside the light-emitting device 200, and the risk that the above-described ultraviolet or visible light or the above-described return light reaches the semiconductor laser element 230. The light-shielding film 322 can be formed of, for example, the same material as the metal film 311.

[0057] (Reflecting member 330) The reflecting member 330 includes a lower surface, a reflecting surface 330a that reflects the light reflected by the reflecting member 260, and a plurality of side surfaces that intersect the reflecting surface 330a and the lower surface. In the illustrated light-emitting device 200, the lower surface, the reflecting surface 330a, and the plurality of side surfaces are each a flat surface.

[0058] The plurality of side surfaces include two side surfaces that face each other with the reflecting surface 330a interposed therebetween. The plurality of side surfaces also include one side surface that intersects the two side surfaces that face each other with the reflecting surface 330a interposed therebetween. The two side surfaces that face each other with the reflecting surface 330a interposed therebetween may have the same area.

[0059] In the illustrated light-emitting device 200, the reflecting surface 330a is rectangular. The reflecting surface 330a is inclined with respect to the lower surface of the reflecting member 330. The inclination angle of the reflecting surface 330a with respect to the lower surface of the reflecting member 330 is, for example, 45 degrees, but is not limited to this angle, and may be, for example, 30° or more and 60° or less.

[0060] Note that the lower surface and the reflecting surface 330a may each be a curved surface, or a flat surface and a curved surface may be mixed. Further, the reflecting surface 330a does not have to be rectangular as long as it can reflect the incident light in a desired direction.

[0061] For the main material forming the outer shape of the reflecting member 330, the same material as that of the reflecting member 260 can be used. Further, the reflecting surface 330a can be formed using, for example, the same material as that of the reflecting member 260.

[0062] (Light-emitting device 200) Next, the light-emitting device 200 will be described.

[0063] The submount 220 is disposed on the upper surface 210a of the base 210. More specifically, the submount 220 is joined to the upper surface 210a of the base 210, for example, via a metal adhesive, on the lower surface side where the metal film 225 is provided. The semiconductor laser element 230 is placed directly or indirectly on the upper surface of the submount 220 disposed on the upper surface 210a of the base 210. For example, the semiconductor laser element 230 is joined to the metal film 223 provided on the upper surface of the submount 220, for example, via a metal adhesive. Examples of the metal adhesive used for these joints include AuSn.

[0064] The semiconductor laser element 230 is arranged such that the emission end face 230a faces the same direction as one side face of the submount 220. Also, the emission end face 230a of the semiconductor laser element 230 can be parallel or perpendicular to, for example, one inner side face or one outer side face of the frame portion 310. The semiconductor laser element 230 emits light traveling in the Z direction. The light emitted from the semiconductor laser element 230 is, for example, blue light. Note that the light emitted from the semiconductor laser element 230 is not limited to blue light.

[0065] The semiconductor laser element 230 is electrically connected to the metal film 317 provided on the upper surface 315a of the step portion 315 via the wiring 280. One end of the wiring 280 is joined to the metal film provided on the upper surface of the semiconductor laser element 230. The light-emitting device 200 has, for example, a plurality of wirings 280. Among the plurality of wirings 280, there is a wiring 280 in which one end of both ends is joined to the metal film 316 provided on the upper surface 315a of the step portion 315, and the other end is joined to the metal film provided on the submount 220. By such connection, power can be supplied to the semiconductor laser element 230 by applying a voltage between the metal films 313 and 314 provided on the upper surface 310a of the frame portion 310.

[0066] The lens 240 is directly or indirectly fixed to the submount 220. In the examples of FIGS. 1 to 7, the lens 240 is fixed to a lens support portion 250 provided on the upper surface of the submount 220. The lens support portion 250 is provided on the upper surface of the submount 220 and supports the lens 240. The lens 240 is supported by the lens support portion 250 by joining the first surface 242a of the extension portion 242 and the lens support portion 250. In this way, by providing the lens support portion 250, the lens 240 can be easily fixed to the submount 220.

[0067] As shown in FIG. 4, the two columnar portions 251 of the lens support portion 250 are located on both sides of the semiconductor laser element 230, and the connecting portion 252 is located above the emission end face 230a side of the semiconductor laser element 230. The lens support portion 250 is positioned so as to straddle the semiconductor laser element 230 and does not prevent the laser light emitted from the semiconductor laser element 230 from entering the lens 240.

[0068] The lens 240 is supported by the lens support portion 250 such that the incident surface 241a of the lens portion 241 faces the emission end face 230a of the semiconductor laser element 230. Specifically, the first surface 242a of the extension portion 242 is joined to the end faces of the two columnar portions 251 of the lens support portion 250 via a joining material 270. With such a structure, since the position of the joining material 270 can be kept away from the incident surface 241a, the possibility that organic substances or the like generated by the joining material 270 contaminate the incident surface 241a by light dust collection can be reduced. Examples of the joining material 270 include AuSn and Au paste.

[0069] As shown in Fig. 4, it is preferable that the bonding material 270 is arranged only on the end face of the columnar portion 251 of the lens support portion 250 and not on the end face of the connecting portion 252. Thereby, the bonding material 270 can be moved away from the region of the incident surface 241a of the lens 240 where the laser light is incident. As a result, it becomes difficult for a part of the bonding material 270 to adhere to the incident surface 241a of the lens 240, so that it is possible to reduce the possibility that the lens 240 is contaminated by a part of the adhered bonding material 270 or the beam pattern is disturbed.

[0070] In addition, metal films may be formed on the first surface 242a of the extending portion 242 of the lens 240 and the end face of the columnar portion 251 of the lens support portion 250, respectively, and these metal films may be joined to each other via, for example, a metal adhesive. Examples of the metal adhesive used for this joining include AuSn and Au paste. Further, when joining the metal films to each other, active alignment may be performed. Active alignment means, for example, adjusting the position and orientation of the lens 240 so that the main light emitted from the semiconductor laser element 230 is incident on the cylindrical surface 241c of the lens 240 in a state where the semiconductor laser element 230 emits the laser light LB.

[0071] The focal point of the lens portion 241 substantially coincides with the center of the light emitting point of the emission end face 230a of the semiconductor laser element 230. The lens portion 241 collimates the laser light LB emitted from the emission end face 230a of the semiconductor laser element 230 in the +Z direction in the YZ plane.

[0072] The reflecting member 260 is disposed on the upper surface 210a of the base 210. For example, the reflecting member 260 is disposed on a metal film provided immediately below. The lower surface of the reflecting member 260 is located below the lower surface 241b of the lens portion 241. Also, it is preferable that the lowermost portion of the reflecting surface 260a is located below the lower surface 241b of the lens portion 241. With this structure, it becomes easier for more of the light emitted from the cylindrical surface 241c to reach the reflecting surface 260a. The reflecting member 260 has a metal film on its lower surface, and this metal film and the upper surface 210a of the base 210 are joined via, for example, a metal adhesive. Examples of the metal adhesive used for this joining include AuSn and Au paste.

[0073] The reflecting member 260 is disposed laterally of the lens portion 241 on the upper surface 210a of the base 210. In the Z direction, the reflecting member 260 is disposed on the side opposite to the semiconductor laser element 230 with the lens portion 241 interposed therebetween. The reflecting surface 260a of the reflecting member 260 faces the direction of the cylindrical surface 241c of the lens portion 241. The reflecting surface 260a reflects the laser light LB emitted from the emission end surface 230a of the semiconductor laser element 230 and passing through the lens portion 241 upward (+Y direction).

[0074] The outer peripheral portion of the upper surface of the base 210 is joined to the lower surface 315b of the step portion 315 of the frame portion 310. In a top view, the submount 220, the semiconductor laser element 230, the lens 240, the lens support portion 250, and the reflecting member 260 are surrounded by the frame portion 310.

[0075] The lid portion 320 is disposed on the upper surface 310a of the frame portion 310. Specifically, the lid portion 320 is supported by the upper surface 310a of the frame portion 310 and is disposed above the semiconductor laser element 230 surrounded by the frame portion 310. The outer peripheral portion of the lower surface 320b of the lid portion 320 is joined to the upper surface 310a of the frame portion 310, for example. For example, a metal film provided on the outer peripheral portion of the lower surface 310b of the lid portion 320 and a metal film 311 provided on the upper surface 310a of the frame portion 310 are joined via AuSn or the like.

[0076] By joining the lower surface 320b of the lid portion 320 to the upper surface 310a of the frame portion 310, a sealed space in which the semiconductor laser element 230 is disposed is formed by the base portion 210, the frame portion 310, and the lid portion 320. Further, this sealed space may be formed in a hermetically sealed state. By hermetically sealing this sealed space, the risk of dust collection of organic substances or the like on the emission end face 230a of the semiconductor laser element 230 can be reduced.

[0077] The reflecting member 330 has its lower surface fixed to the upper surface 320a of the lid portion 320 via a resin layer 340. The reflecting surface 330a of the reflecting member 330 at least partially overlaps with the light transmission region 320t of the lid portion 320 and the reflecting surface 260a of the reflecting member 260 in a top view. The resin constituting the resin layer 340 can be, for example, a thermosetting resin that is cured by heating, or a photocurable resin that is cured by irradiation with ultraviolet rays or visible light.

[0078] The laser light LB reflected in the +Y direction by the reflecting surface 260a of the reflecting member 260 passes through the light transmission region 320t of the lid portion 320 and reaches the reflecting surface 330a of the reflecting member 330. The laser light LB that has reached the reflecting surface 330a of the reflecting member 330 is reflected by the reflecting surface 330a, and the traveling direction is changed to the +Z direction.

[0079] When forming the resin layer 340, active alignment may be performed before curing the resin. That is, when forming the resin layer 340, with the semiconductor laser element 230 emitting the laser light LB, after adjusting the position and orientation of the reflecting member 330 so that the reflecting surface 330a changes the traveling direction of the laser light LB to the +Z direction, the resin may be cured.

[0080] In the light-emitting device 200, by thinning the submount 220, the heat dissipation can be improved and the device can be made thinner. However, for example, when using the lens 240x shown in FIG. 9, if the submount 220 is thinned, when the lens 240x is mounted in the manufacturing process of the light-emitting device 200, the lower surface 243b of the lens portion 243 may contact the upper surface 210a of the base 210, and the lens 240x may fall off. On the other hand, as described above, the lens 240 shown in FIG. 8 has a shape in which the portion on the -Y side of the virtual line VL of the lens 240x is removed, and the length in the Y direction is shorter than that of the lens 240x. Therefore, when using the lens 240 shown in FIG. 8, even if the submount 220 is thinned, when the lens 240 is mounted in the manufacturing process of the light-emitting device 200, the possibility that the lower surface 241b of the lens portion 241 contacts the upper surface 210a of the base 210 can be reduced. That is, by using the lens 240 shown in FIG. 8, the submount 220 can be thinned while reducing the possibility that the lens 240 contacts the upper surface 210a of the base 210, improving the heat dissipation of the light-emitting device 200, and making it thinner. Hereinafter, a specific description will be given with reference to FIG. 10.

[0081] FIG. 10 is an enlarged cross-sectional view showing an enlarged view of the lens portion and its vicinity of the light-emitting device shown in FIG. 7. In FIG. 10, B indicates the generatrix of the lens portion 241 that is the farthest from the emission end surface 230a in the normal direction (Z direction) of the emission end surface 230a among the generatrices of the lens portion 241. The generatrix B is parallel to the X direction. Here, considering a virtual plane P that includes the generatrix B and is parallel to the lower surface 241b of the lens portion 241, with respect to the virtual plane P, the shape of the lens portion 241 is symmetric with respect to the virtual plane P within a range of a predetermined distance L1 in the normal direction (Y direction) of the virtual plane P. The predetermined distance L1 can be, for example, 0.2 mm or less.

[0082] On one hand, in the direction opposite to the lower surface 241b from the virtual plane P, the lens portion 241 exists longer than a predetermined distance L1. In the Y direction, the length of the lens portion 241 in the direction opposite to the lower surface 241b from the virtual plane P is "predetermined distance L1 + distance L2 (L2>0)". That is, the lower surface 241b of the lens portion 241 is at a position of a predetermined distance L1 from the virtual plane P, but the upper end of the lens portion 241 is at a position of "predetermined distance L1 + distance L2" from the virtual plane P. In the example of FIG. 10, the upper end of the lens portion 241 is the boundary between the cylindrical surface 241c of the lens portion 241 and the second surface 242b of the extension portion 242.

[0083] By setting the lower surface 241b of the lens portion 241 at a position of a predetermined distance L1 from the virtual plane P, the length below the virtual plane P can be shortened. Therefore, even if the submount 220 is made thinner, the distance between the lower surface 241b of the lens portion 241 and the upper surface 210a of the base portion 210 can be increased, and the possibility of the lower surface 241b of the lens portion 241 coming into contact with the upper surface 210a of the base portion 210 can be reduced. In the light emitting device 200, a gap G exists between the lower surface 241b of the lens portion 241 and the upper surface 210a of the base portion 210.

[0084] Also, when molding the lens, a larger size of the lens portion 241 can reduce the relative dimensional error. Therefore, when manufacturing a lens of a predetermined size, rather than manufacturing a lens 240x with a cylindrical surface 243c of a predetermined size, manufacturing a lens with a larger cylindrical surface first, and then cutting the lower side of the lens from the virtual plane P by dicing or the like, so that the length of the lens portion 241 in the direction opposite to the lower surface 241b from the virtual plane P is "predetermined distance L1 + distance L2", the lens 240 can be manufactured with higher dimensional accuracy. Note that when manufacturing the lens, a lens can be prepared such that the curved surface shape of the cylindrical surface is symmetric with respect to the virtual plane P exceeding a predetermined distance L1, and then, among the lens portions including the cylindrical surface having a curvature, the portion existing below the position exceeding a predetermined distance L1 from the virtual plane P is cut to manufacture the lens 240.

[0085] From the viewpoints of improving the heat dissipation performance and reducing the thickness of the light-emitting device 200, it is preferable that the thickness of the submount 220, that is, the distance L3 in the Y direction between the upper surface and the lower surface of the submount 220, is 250 μm or more and less than 350 μm. In this case, in the light-emitting device 200, the distance L4 in the Y direction between the lower surface 241b of the lens portion 241 and the upper surface 210a of the base portion 210 can be 80 μm or more. The distance L4 is more preferably 100 μm or more. By setting the distance L4 to 80 μm or more, even considering the design tolerance, the possibility that the lower surface 241b of the lens portion 241 contacts the upper surface 210a of the base portion 210 can be reduced. By setting the distance L4 to this value, when the submount 220 with the lens 240 attached is disposed on the upper surface 210a of the base portion 210, the possibility that the lens 240 and the base portion 210 contact each other can be reduced.

[0086] The lower surface 241b of the lens portion 241 is preferably parallel to the lower surface of the submount 220. Thereby, when the submount 220 with the lens 240 attached is disposed on the upper surface 210a of the base portion 210, it becomes easy to secure a distance L4 of 80 μm or more, and the thickness of the light-emitting device 200 can be reduced. The lower surface 241b of the lens portion 241 is preferably located below the lower surface of the semiconductor laser element 230. The lower surface 241b of the lens portion 241 is preferably located below the upper surface of the submount 220. With such a structure, it becomes easy for the light emitted from the semiconductor laser element 230 to reach the cylindrical surface 241c.

[0087] In FIG. 10, the region surrounded by the two-dot chain line indicates the range of the main light emitted from the semiconductor laser element 230. Among the main light emitted from the semiconductor laser element 230, it is preferable that the light traveling most downward does not enter the lower surface 241b of the lens portion 241 but reaches the cylindrical surface 241c. Thereby, the main light emitted from the semiconductor laser element 230 can be extracted without leaking from the lower surface 241b of the lens portion 241. Also, among the main light emitted from the semiconductor laser element 230, it is preferable that the light traveling most downward enters the reflecting surface 260a of the reflecting member 260. Thereby, since the light reflected upward by the reflecting surface 260a of the reflecting member 260 increases among the laser light emitted from the semiconductor laser element 230, the light utilization efficiency in the light emitting device 200 can be improved.

[0088] Also, the optical axis OA of the laser light emitted from the semiconductor laser element 230 is preferably included in the virtual plane P. Thereby, light that is nearly parallel to the Z direction can be emitted from the cylindrical surface 241c of the lens portion 241. As a result, more of the main light emitted from the semiconductor laser element 230 enters the reflecting surface 260a of the reflecting member 260, so that the light utilization efficiency in the light emitting device 200 can be improved.

[0089] (Modification example) FIG. 11 is an enlarged cross-sectional view showing an enlarged view of the lens portion and its vicinity of the light emitting device according to the modification example. The light emitting device shown in FIG. 11 is different from the light emitting device 200 shown in FIGS. 1 to 8 in that the lens 240 is replaced with the lens 240A and the lens support portion 250 is not provided.

[0090] The lens 240A is composed only of a portion corresponding to the lens portion 241 of the lens 240 and does not have a portion corresponding to the extending portion 242. The lens 240A is directly joined to the end of the submount 220 via the bonding material 270 below the incident surface 241a.

[0091] Thus, the lens according to the present disclosure may not have an extension portion and may be directly fixed to the submount without using a lens support portion. In this case as well, the same effects as those of the first embodiment are achieved.

[0092] Although the preferred embodiments and the like have been described in detail above, the present invention is not limited to the above-described embodiments and the like, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope described in the claims.

[0093] In addition to the above embodiments, the following additional notes are disclosed. (Additional Note 1) A base, A submount disposed on the upper surface of the base, A semiconductor laser element disposed on the upper surface of the submount and emitting light from an emission end face, A lens that is directly or indirectly fixed to the submount and has a cylindrical surface, The lens includes an incident surface of the light and a lower surface connected to the incident surface, and the incident surface includes a lens portion facing the emission end face of the semiconductor laser element. Among the generatrices of the lens portion, including the generatrix that is farthest from the emission end face in the normal direction of the emission end face, with respect to a virtual plane parallel to the lower surface, the lens portion is symmetric with respect to the virtual plane within a range of a predetermined distance in the normal direction of the virtual plane. In the direction opposite to the lower surface from the virtual plane, the lens portion exists longer than the predetermined distance. The lower surface of the lens portion is at a position of the predetermined distance from the virtual plane. A light-emitting device in which a gap exists between the lower surface of the lens portion and the upper surface of the base. (Additional Note 2) The light-emitting device according to Additional Note 1, wherein the lower surface of the lens portion is parallel to the lower surface of the submount. (Additional Note 3) Among the main light emitted from the semiconductor laser element, the light traveling most downward does not exit from the lower surface of the lens portion, the light-emitting device according to Additional Note 1 or 2. (Appendix 4) The optical axis of the light emitted from the semiconductor laser element is included in the virtual plane, and the light-emitting device according to any one of Appendices 1 to 3. (Appendix 5) The lens further includes an extending portion that extends from the lens portion to the side opposite to the lower surface, and the light-emitting device according to any one of Appendices 1 to 4. (Appendix 6) The light-emitting device according to Appendix 5, which is provided on the upper surface of the submount and has a lens support portion for supporting the lens. (Appendix 7) The extending portion is continuous with the incident surface and has a first surface located in the same plane as the incident surface. The lens is supported by the lens support portion when the first surface of the extending portion and the lens support portion are joined, and the light-emitting device according to Appendix 6. (Appendix 8) The distance between the upper surface and the lower surface of the submount is 250 μm or more and less than 350 μm, and the distance between the lower surface of the lens portion and the upper surface of the base is 80 μm or more, and the light-emitting device according to any one of Appendices 1 to 7. (Appendix 9) The light-emitting device according to any one of Appendices 1 to 8, further including a reflecting member disposed on the upper surface of the base, having a reflecting surface for reflecting upward the light emitted from the semiconductor laser element and passing through the lens portion. (Appendix 10) Among the main light emitted from the semiconductor laser element, the light traveling most downward enters the reflecting surface, and the light-emitting device according to Appendix 9.

Explanation of Reference Numerals

[0094] 200 Light-emitting device 210 Base 210a Upper surface 210b Lower surface 220 Submount 223, 225 Metal film 230 Semiconductor laser element 230a Emission end face 240, 240A Lens 241 Lens portion 241a Incident surface 241b Lower surface 241c Cylindrical surface 242 Extension part 242a First surface 242b Second surface 242c Third surface 250 Lens support part 251 Columnar part 252 Connecting part 260 Reflective member 260a Reflective surface 270 Bonding material 280 Wiring 310 Frame part 310a Upper surface 310b Lower surface 311, 312, 313, 314, 316, 317 Metal film 315 Step part 315a Upper surface 315b Lower surface 320 Cover part 320a Upper surface 320b Lower surface 320t Light transmission region 322 Light-shielding film 330 Reflective member 330a Reflective surface 340 Resin layer

Claims

1. a base, a submount disposed on an upper surface of the base, a semiconductor laser element disposed on an upper surface of the submount and emitting light from an emission end face, and a lens directly or indirectly fixed to the submount and having a cylindrical surface. The lens includes an incident surface of the light and a lower surface connected to the incident surface, and the incident surface includes a lens portion facing the emission end face of the semiconductor laser element. Among generatrices of the lens portion, a generatrix farthest from the emission end face in a normal direction of the emission end face is included, and with respect to a virtual plane parallel to the lower surface, the lens portion is symmetric with respect to the virtual plane within a range of a predetermined distance in a normal direction of the virtual plane. In a direction opposite to the lower surface from the virtual plane, the lens portion exists longer than the predetermined distance. A lower surface of the lens portion is at a position of the predetermined distance from the virtual plane. A light-emitting device, wherein a gap exists between the lower surface of the lens portion and the upper surface of the base.

2. The light-emitting device according to claim 1, wherein the lower surface of the lens portion is parallel to a lower surface of the submount.

3. The light-emitting device according to claim 1, wherein among main light emitted from the semiconductor laser element, light traveling most downward is not emitted from the lower surface of the lens portion.

4. The light-emitting device according to claim 1, wherein an optical axis of light emitted from the semiconductor laser element is included in the virtual plane.

5. The light-emitting device according to claim 1, wherein the lens further includes an extension portion extending from the lens portion to a side opposite to the lower surface.

6. The light-emitting device according to claim 5, further comprising a lens support portion provided on an upper surface of the submount and supporting the lens.

7. The extension portion is continuous with the incident surface and includes a first surface located in the same plane as the incident surface. The lens is supported by the lens support portion when the first surface of the extension portion is joined to the lens support portion. The light-emitting device according to claim 6.

8. The distance between the upper surface and the lower surface of the submount is 250 μm or more and less than 350 μm, and the distance between the lower surface of the lens portion and the upper surface of the base portion is 80 μm or more. The light-emitting device according to any one of claims 1 to 7.

9. The light-emitting device according to any one of claims 1 to 7, further comprising a reflecting member disposed on the upper surface of the base portion and having a reflecting surface that reflects upward the light emitted from the semiconductor laser element and passing through the lens portion.

10. Among the main light emitted from the semiconductor laser element, the light traveling most downward is incident on the reflecting surface. The light-emitting device according to claim 9.

Images