Light source device

Abstract

To provide a light source device that can more effectively prevent misalignment of the optical axis of a semiconductor laser element with respect to an optical member due to heat generated by driving the semiconductor laser element in the light source device.SOLUTION: The light source device includes a substrate, at least one semiconductor laser element arranged on the substrate, and at least one lens arranged on the light-emitting side of the semiconductor laser element. The substrate has a flat portion for placing the semiconductor laser element and at least two protrusions arranged on both sides of the semiconductor laser element and on the light-emitting side of the semiconductor laser element. The lens is fixed to the protrusions at least in two places by means of a first bonding material.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

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

[0002] Conventionally, light source devices have been proposed in which a semiconductor laser element is housed in a package, and the semiconductor laser element and optical members are fixed with an adhesive after their positions are adjusted (Patent Document 1, etc.). In such light source devices, in order to prevent misalignment of the optical axis of the semiconductor laser element with respect to the optical members, various measures have been taken by selecting the material or shape of the substrate, by using various ingenuity in the method of fixing the optical members, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2018-186234 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a light source device that can suppress misalignment of the optical axis of a semiconductor laser element with respect to an optical member caused by heat generated by driving the semiconductor laser element in the light source device. [Means for solving the problem]

[0005] The light source device of the present application comprises: a substrate; at least one semiconductor laser element disposed on the substrate; at least one lens disposed on the light emission side of the semiconductor laser element; the substrate has a flat plate portion for mounting the semiconductor laser element thereon, and at least two protrusions disposed on both sides of the semiconductor laser element and on the light emission side; The lens is fixed to the protrusion at at least two locations by a first bonding material. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a light source device that can suppress misalignment of the optical axis of a semiconductor laser element with respect to an optical member caused by heat generated by driving the semiconductor laser element in the light source device. [Brief explanation of the drawings]

[0007] [Figure 1A] FIG. 1 is a perspective view of a light source device according to a first embodiment. [Figure 1B] FIG. 1B is a plan view of the light source device of FIG. 1A. [Figure 1C] FIG. 1B is a right side view of FIG. 1A. [Figure 1D] FIG. 1B is a front view of FIG. 1A. [Figure 1E] FIG. 1B is a perspective view of a modified example of the light source device shown in FIG. 1A. [Figure 1F] FIG. 1C is an enlarged view of a portion of FIG. 1B. [Figure 2A] FIG. 10 is a perspective view of a light source device according to a second embodiment. [Figure 2B] FIG. 2B is a plan view of the light source device of FIG. 2A. [Figure 2C] FIG. 2B is a right side view of FIG. 2A. [Figure 2D] FIG. 2B is a front view of FIG. 2A. [Figure 3A] FIG. 11 is a perspective view of a light source device according to a third embodiment. [Figure 3B] FIG. 3B is a plan view of the light source device of FIG. 3A. [Figure 3C] FIG. 3B is a right side view of FIG. 3A. [Figure 3D] FIG. 3B is a front view of FIG. 3A. [Figure 4A] FIG. 10 is a perspective view of a light source device according to a fourth embodiment. [Figure 4B] FIG. 4B is a plan view of the light source device of FIG. 4A. [Figure 4C] FIG. 4B is a right side view of FIG. 4A. [Figure 4D] FIG. 4B is a front view of FIG. 4A. [Figure 5A] FIG. 10 is a perspective view of a light source device according to a fifth embodiment. [Figure 5B] FIG. 5B is a plan view of the light source device of FIG. 5A. [Figure 5C] FIG. 5B is a right side view of FIG. 5A. [Figure 5D] FIG. 5B is a front view of FIG. 5A. [Figure 6A] FIG. 13 is a perspective view of a light source device according to a sixth embodiment. [Figure 6B] FIG. 6B is a plan view of the light source device of FIG. 6A. [Figure 6C] FIG. 6B is a right side view of FIG. 6A. [Figure 6D] FIG. 6B is a front view of FIG. 6A. [Figure 7A] FIG. 13 is a perspective view of a light source device according to a seventh embodiment. [Figure 7B] FIG. 6 is a cross-sectional view taken along line VIIB-VIIB in FIG. 7A. [Figure 7C] This is a modified example of the light source device shown in FIG. 7B. [Figure 8A] FIG. 2 is a perspective view of a lens of the light source device of the present application. [Figure 8B] FIG. 8B is a side view showing a modified example of the lens shown in FIG. 8A. [Figure 8C] FIG. 8B is a perspective view showing another modified example of the lens shown in FIG. 8A. [Figure 8D] FIG. 8B is a perspective view showing yet another modified example of the lens shown in FIG. 8A. [Figure 8E] FIG. 8B is a perspective view showing yet another modified example of the lens shown in FIG. 8A. DETAILED DESCRIPTION OF THE INVENTION

[0008] In this specification and claims, polygons such as triangles and quadrilaterals include shapes in which the corners of the polygon have been rounded, chamfered, corner-cut, or rounded. Shapes in which not only the corners (edges) but also the middle portions of the edges are also referred to as polygons. In other words, shapes that have been partially processed while retaining the polygonal base are included in the interpretation of "polygon" as described in this specification and claims. The same applies to terms that describe specific shapes, such as trapezoid, circle, and concave / convex, and expressions that describe the individual edges that form those shapes. In other words, even if the corners or middle portions of a certain edge have been processed, the processed portion is also included in the interpretation of "edge." To distinguish "polygons" and "edges" without partial processing from processed shapes, the term "strict" is sometimes used, such as "strict quadrilateral." Furthermore, when there are multiple equivalents to a certain element and each element needs to be distinguished, the element may be distinguished by appending "first" or "second." If the objects or perspectives distinguished between the present specification and the claims are different, the same appendix may not refer to the same object between the present specification and the claims. For example, if the present specification distinguishes between elements marked "first," "second," and "third," and the claims are written with only the "first" and "third" elements in the present specification as the subject matter, the elements marked "first" and "second" in the claims may refer to the elements marked "first" and "third" in the present specification. Furthermore, in this specification, the surface of the light source device from which the light of the semiconductor laser element is emitted is referred to as the front surface. Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the embodiments shown do not limit the present invention. Furthermore, in the following description, the same names and symbols indicate the same or similar components, and duplicate explanations may be omitted as appropriate. The size and positional relationship of components shown in each drawing may be exaggerated. For reference, the drawings show mutually orthogonal X, Y, and Z axes. The light source device can be oriented in any direction during use, but for ease of explanation, the surface of the flat portion of the substrate will be referred to as the XY plane.

[0009] <Embodiment 1> 1A to 1D for describing an exemplary embodiment, a light source device 10 of the first embodiment includes a substrate 11, at least one semiconductor laser element 12 disposed on the substrate 11, and at least one lens 13 disposed on the light emission side of the semiconductor laser element 12. The substrate 11 has a flat plate portion 11a and at least two protrusions 11b. The lens 13 is fixed to the protrusion 11b at at least two locations by a first bonding material 14. With this configuration, the lens 13, which is positioned and fixed relative to the optical axis of the light emitted from the semiconductor laser element 12, can be positioned while suppressing misalignment even if the first bonding material expands or contracts due to heat caused by driving the semiconductor laser element 12.

[0010] (Substrate 11) The substrate 11 has a flat plate portion 11a for mounting the semiconductor laser element 12, and at least two protrusions 11b arranged on both sides of the semiconductor laser element 12 and on the light-emitting side. As long as the substrate 11 has the flat plate portion 11a and the two protrusions 11b, it may further have side walls, recesses, etc. surrounding the flat plate portion 11a. The surface on which the flat plate portion 11a, protrusions 11b, side walls, recesses, etc. are arranged can be defined as the first main surface of the substrate 11. The substrate 11 has a second main surface opposite the first main surface, and the second main surface is preferably flat. 1A, the protrusions 11b can be convex portions extending in the Z-axis direction from the flat plate portion 11a of the substrate 11, i.e., the XY plane. However, they may not only extend perpendicularly to the XY plane, but also extend at an angle to the XY plane. Furthermore, the surface of the flat portion 11a and the upper surfaces 11bb (or the highest portions in the Z-axis direction) of the two protrusions 11b are not limited to having a height difference such that one is higher than the other, but may be flush or approximately flush. For example, as shown in Fig. 3A, the surface of the flat plate portion 31a may be connected to the upper surfaces 31bb of the two protrusions 31b, and the heights of the upper surfaces of the flat plate portion 31a and the upper surfaces 31bb of the protrusions 31b (e.g., the height from the second main surface of the substrate 31) may be the same or approximately the same. Here, "approximately flush" and "approximately the same" mean that the difference in height is allowed to be about ±5% of the total thickness of the substrate. In other words, the protrusions 31b may have walls that define recesses 31d, as shown in Fig. 3A. As shown in FIG. 4A, the substrate 41 may have a protrusion 41b1 formed by a wall portion that forms the recess 41d, and a protrusion 41b2 disposed thereon. 5A and 6A, when a plurality of semiconductor laser elements 12 are arranged, the substrates 51 and 61 may have a plurality of protrusions 51b and 61b arranged corresponding to the plurality of semiconductor laser elements 12. In this case, two protrusions 51b and 61b may not be arranged for every semiconductor laser element 12, and the protrusions 51b and 61b may be shared between adjacent semiconductor laser elements 12.

[0011] The flat plate portion 11a may be a portion that is strictly flat, or may have irregularities on its surface to the extent that it does not interfere with placing the semiconductor laser element 12. Regardless of whether the flat plate portion 11a has irregularities, it is preferable that the flat plate portion 11a is not inclined with respect to the surface opposite the flat plate portion 11a, i.e., the second main surface of the substrate 11. In other words, it is preferable that the flat plate portion 11a is parallel or approximately parallel to the second main surface. Here, approximately parallel means that an inclination of about ±5° is allowed. The size of the flat plate portion 11a is not particularly limited, as long as the planar area of ​​the flat plate portion 11a in a plan view is larger than the planar area of ​​the semiconductor laser element 12. As will be described later, when a plurality of semiconductor laser elements 12 are arranged on the substrate 11, the flat plate portion 11a preferably has an area that is larger than the planar area of ​​the plurality of semiconductor laser elements 12, as well as an area that allows the semiconductor laser elements 12 to be arranged sufficiently far apart so that they do not come into contact with each other and the wiring and the like connected to the semiconductor laser elements 12 can function. Furthermore, as will be described later, when the semiconductor laser element 12 is arranged on the substrate 11 via a submount 15, the flat plate portion 11a preferably has an area that is larger than the planar area of ​​the submount 15.

[0012] The two protrusions 11b are portions for holding the lens 13, and are arranged on both sides and the light emission side of the semiconductor laser element 12. Here, "both sides and the light emission side" means both sides of the light emitted from the semiconductor laser element 12 when the semiconductor laser element 12 is arranged on a flat plate portion, in other words, positions that sandwich the light. When viewed from the direction in which the protrusions 11b extend (i.e., the Z-axis direction), the two protrusions 11b can be arranged so that a straight line K (arrow K in FIG. 1D) connecting them at the shortest distance is perpendicular to the optical axis of the semiconductor laser element 12. The two protrusions 11b are preferably arranged so that the straight line K is perpendicular to the light emitted from the semiconductor laser element 12. By arranging the two protrusions 11b in this manner, it becomes possible to position the lens 13 in an appropriate position with respect to the optical axis of the semiconductor laser element 12. The shortest distance here is, for example, 0.2 mm or more and 5.5 mm or less, and preferably 0.3 mm or more and 1.5 mm or less. The shape of the protrusion 11b may be any of a cylinder, a rectangular parallelepiped, a cube, a polygonal prism such as a pentagonal prism, a dome, a truncated cone or a truncated polygonal pyramid, a shape missing a portion of these, or a combination of these. Among these, a rectangular prism is preferable for the protrusion 11b. This shape allows the lens 13 to be stably fixed in place. In particular, the two protrusions 11b are preferably rectangular prisms having parallel side surfaces 11ee sandwiching the light emitted from the semiconductor laser element 12. However, a tilt of ±5° from the parallelism here is allowed. The side surface 11ee is preferably a plane perpendicular to the flat plate portion 11a, for example. In this case, of the two side surfaces adjacent to the side surface 11ee of the protrusion 11b, the side surface facing the semiconductor laser element 12 is referred to as side surface 11aa, and the side surface opposite the semiconductor laser element 12 is referred to as side surface 11cc.

[0013] The height (H in FIG. 1D) of protrusion 11b can be adjusted as appropriate depending on the shape, size, etc. of lens 13 to be fixed. For example, protrusion 11b preferably has a height greater than the distance from the center to the outer edge of lens 13 to be fixed, so that the optical axis of semiconductor laser element 12 can be adjusted to pass through the optical axis of lens 13. In other words, when lens 13 is fixed to protrusion 11b, the height is preferably such that the lowest end of lens 13 does not come into contact with substrate 11. Specifically, the height H of protrusion 11b from the surface of flat plate portion 11a or substrate 11 is 0.5 mm or more and 5.0 mm or less, and preferably 1.0 mm or more and 3.0 mm or less. The length of the protrusion 11b in the X direction or Y direction in plan view may be at least large enough to ensure a contact area with the first bonding material capable of fixing the lens 13. Specifically, the length is 0.2 mm or more and 3.0 mm or less, and preferably 0.5 mm or more and 1.5 mm or less. The two protrusions 11b may have different shapes and sizes, but preferably have the same shape and size.

[0014] The substrate 11 can be formed primarily of ceramic or entirely of ceramic. Examples of ceramic include aluminum nitride, silicon nitride, aluminum oxide, and silicon carbide. Because ceramics have a low linear expansion coefficient, forming the substrate 11 from ceramic reduces the effects of thermal expansion and / or contraction. As a result, as described below, displacement of the fixed lens 13 can be suppressed. The substrate 11 may partially contain a metal, an inorganic substance, or a composite thereof. Examples of metals, inorganic substances, and composites thereof include gold, silver, tungsten, nickel, copper, aluminum, iron, diamond, copper molybdenum, copper-diamond composites, and copper tungsten. The protrusions 11b may be formed from the same material as the flat portion 11a of the substrate 11, or from a different material. The protrusions 11b may be formed integrally with the flat portion 11a of the substrate 11, or may be formed separately and then bonded to each other. Substrate 11 may have metal portions 11g, 11h, etc., provided on its surface or inside as wiring for electrical connection, etc. Examples of materials that can be used for the metal portions include gold, aluminum, silver, copper, tungsten, titanium, platinum, nickel, iron, tin, etc., or alloys thereof. The shortest distance between metal portion 11h and protrusion 11b as viewed in the Z-axis direction is, for example, 0.1 mm or more and 5.0 mm or less, and preferably 0.3 mm or more and 3.0 mm or less. The outer shape of substrate 11 may be any of polygonal shapes such as triangle or square, circular or elliptical in plan view, and is preferably rectangular. The length of substrate 11 in the X or Y direction in plan view is, for example, 1.0 mm or more and 10.0 mm or less, and preferably 2.0 mm or more and 6.0 mm or less. The thickness of substrate 11 can be appropriately set so as to ensure the strength sufficient to support semiconductor laser element 12, lens 13, etc., to be arranged thereon. The substrate 11 may be a part of a housing-like package that houses the semiconductor laser element 12 in a recess.

[0015] (semiconductor laser element 12) The semiconductor laser element 12 may be either an edge-emitting or surface-emitting semiconductor laser element. Of these, it is preferable to use an edge-emitting type. An edge-emitting semiconductor laser element forms an elliptical far-field pattern (hereinafter sometimes referred to as "FFP") on a plane parallel to the light-emitting end face, and the light passing through the center of the elliptical shape of the FFP, i.e., the light with the peak intensity in the light intensity distribution of the FFP, is referred to as the optical axis of the semiconductor laser element. Also, for a surface-emitting semiconductor laser element, the light with the peak intensity in the light intensity distribution of light emitted from the light-emitting facet is referred to as the optical axis of the semiconductor laser element. The semiconductor laser element 12 may be any one of a semiconductor laser element that emits blue light, a semiconductor laser element that emits green light, a semiconductor laser element that emits red light, a semiconductor laser element that emits infrared light, etc., or a semiconductor laser element that emits light other than these. Blue light refers to light whose emission peak wavelength is in the range of 420 nm to 494 nm, green light refers to light whose emission peak wavelength is in the range of 495 nm to 570 nm, red light refers to light whose emission peak wavelength is in the range of 605 nm to 750 nm, and infrared light refers to light whose emission peak wavelength is in the range of 780 nm to 2500 nm. Examples of semiconductor laser elements that emit blue or green light include semiconductor laser elements containing nitride semiconductors. Examples of nitride semiconductors include GaN, InGaN, and AlGaN. Examples of semiconductor laser elements that emit red light include those containing semiconductors such as InAlGaP, GaInP, GaAs, and AlGaAs. Examples of semiconductor laser elements that emit infrared light include those containing GaAs or InP semiconductors such as GaInAsP, AlGaInAs, and InGaAs, and those containing In X Al Y Ga 1-X-Y Examples of suitable semiconductors include gallium nitride semiconductors represented by N (0≦X, 0≦Y, X+Y<1). The semiconductor laser element 12 may be either a single emitter or a multi-emitter.

[0016] The semiconductor laser element 12 is disposed on the flat plate portion 11a of the substrate 11. The semiconductor laser element 12 is preferably disposed on the flat plate portion 11a of the substrate 11 via a submount 15. The semiconductor laser element 12 is preferably fixed onto the substrate 11 and / or the submount 15 via a second bonding material. The submount 15 has two bonding surfaces, one of which is provided on the opposite side of the other bonding surface. The submount 15 can be formed using, for example, ceramics such as silicon nitride, aluminum nitride, or silicon carbide; metals such as gold, silver, copper, tungsten, or nickel; or diamond. The semiconductor laser element 12 is preferably fixed to one of the bonding surfaces of the submount 15. The second bonding material preferably has a smaller linear expansion coefficient than the first bonding material described below, specifically, a linear expansion coefficient of 3 to 30 ppm / °C at room temperature. By using a second bonding material with a small linear expansion coefficient, it is possible to suppress misalignment of the semiconductor laser element 12 with respect to the lens 13 described below due to temperature changes. Examples of the second bonding material include tin-bismuth, tin-copper, tin-silver, and gold-tin solders; eutectic alloys such as alloys mainly composed of Au and Sn, alloys mainly composed of Au and Si, and alloys mainly composed of Au and Ge; conductive pastes such as silver, gold, and palladium; bumps; anisotropic conductive materials such as ACP and ACF; brazing filler metals of low-melting point metals; conductive adhesives and conductive composite adhesives combining these materials.

[0017] (Lens 13) The lens 13 is fixed to the two protrusions 11b at at least two locations by the first bonding material 14. In particular, it is preferable that the lens 13 is fixed in contact with only the two protrusions 11b via the first bonding material 14. The lens 13 is used to diverge, converge, or collimate the light emitted from the semiconductor laser element 12 . Lens 13 may have any lens surface 13a, such as a concave surface, a convex surface, a concave-convex surface, an aspherical surface, or the like. Lens 13 may have lens surfaces 13a on opposing surfaces, or may have non-lens surfaces that do not function as lenses, as shown in FIGS. 8B to 8E. Lens 13 may have one lens surface 13a, or may have multiple lens surfaces 13a depending on the number of semiconductor laser elements 12 mounted in light source device 10. When multiple lens surfaces 13a are provided, lens 13 may be arranged such that the multiple lens surfaces 13a are connected together, as shown in FIG. 8D, or may be arranged such that the multiple lens surfaces 13a are independent of each other, as shown in FIG. 8E. As shown in FIGS. 8A to 8E , the lens 13 may have a lens surface 13a, a surface 13c opposite to the lens surface 13a, a side surface 13d in contact with the lens surface 13a and / or the opposite surface 13c, and optionally a surface 13b in contact with only the lens surface 13a and the side surface 13d. The side surface 13d is preferably parallel or approximately parallel to the light transmission direction. Here, approximately parallel allows for an angle of ±5°. In particular, the lens 13 preferably has, in addition to the lens surface 13a, a side surface 13d that is parallel or approximately parallel to the light transmission direction. Making the side surface 13d parallel can reduce the amount of the first bonding material 14 (described later) required to secure the lens 13, and can prevent the lens 13 from shifting due to a volume change of the first bonding material 14 caused by temperature-dependent changes in the surface 13a. Lens surface 13a, surface 13b that is in contact only with side surface 13d, opposite surface 13c, and side surface 13d may be curved surfaces, but preferably include flat surfaces, and more preferably are flat surfaces. The outer shape of lens 13, when viewed from the lens surface 13a side, may be any of a circle, a polygon such as a square or a pentagon, a shape missing a part of these, or a shape combining parts of these. Among these, it is preferable that lens 13 has a square outer shape. The size, thickness, etc. of the lens 13 can be set appropriately depending on the characteristics of the light source device to be obtained. For example, the diameter or length of one side of the lens 13 can be 0.1 mm or more and 5.0 mm or less, and preferably 0.5 mm or more and 1.5 mm or less. When lens 13 is positioned so as not to overlap semiconductor laser element 12 in plan view, it can be positioned so that the distance from the light-emitting end face of semiconductor laser element 12 (Ly in FIG. 1C) is 0.05 mm to 5.0 mm, preferably 0.5 mm to 3.0 mm. Furthermore, lens 13 can be positioned so that the distance from side surface 11ee of protrusion 11b is 0.05 mm to 1.0 mm, preferably 0.1 mm to 0.4 mm. When lens 13 is positioned so as not to overlap semiconductor laser element 12 in plan view, it can be positioned so that the distance from substrate 11 (Lz in FIG. 1D) is 0.05 mm to 2.0 mm, preferably 0.1 mm to 0.5 mm. By setting the positional relationship of lens 13 with substrate 11, side surface 11ee of protrusion 11b, and semiconductor laser element 12 in this manner, the light source device can be made more compact. As a result, material tolerances are reduced, and side surface 13d of lens 13 and side surface 11ee of protrusion 11b approach precise flatness, which reduces the amount of bonding material (described later), further suppresses the effects of thermal expansion or contraction of the bonding material, and prevents misalignment of lens 13. Furthermore, when the distance between lens 13 and the light-emitting end surface is reduced, the beam of light emitted from semiconductor laser element 12 can be made thinner, which allows the corresponding side of lens 13 to be made smaller, and further reduces the size of the optical system in the subsequent stage, thereby enabling a more compact light source device. The lens 13 is preferably translucent, and not only the lens surface 13a but also the non-lens surface is translucent. The lens 13 can be formed using, for example, glass such as BK7, plastic (polycarbonate, acrylic resin, cycloolefin polymer, etc.), a mixture or combination of glass and plastic, etc. In addition, when the lens surface 13a of the lens 13 is fixed by the protrusion 11b so that it is positioned on the front side, of the side surfaces 13d of the lens 13, the side surface 13d parallel to the side surface 11ee of the protrusion 11b is called side surface 13ff, and the side surface 13d facing the substrate 11 is called side surface 13dd.

[0018] (1st bonding material 14) The first bonding material 14 is used to fix the lens 13. Any adhesive commonly used may be used as the first bonding material 14. Among these, a material formed from a light-transmitting material is preferable. Furthermore, the first bonding material 14 preferably has a relatively small linear expansion coefficient, specifically, a linear expansion coefficient of 30 to 200 ppm / °C at room temperature. For example, the first bonding material 14 may be made of an organic material, such as a thermoplastic resin or a thermosetting resin. Examples of thermoplastic resins include vinyl acetate, polyvinyl acetal, vinyl acetate copolymer, ethylene vinyl acetate, vinyl chloride, acrylic, polyester, polyamide, cellulose, olefin, and styrene. Examples of thermosetting resins include urea, melamine, phenol, resorcinol, epoxy, acrylic, polyester, polyurethane, silicone, polyamide, polybenzimidazole, polyimide, and isocyanate. Alternatively, ultraviolet-curable, visible light-curable, or electron beam-curable resins may be used. In particular, the use of an ultraviolet-curable adhesive is more preferable because it facilitates active alignment, which fixes the lens 13 at a desired position while searching for a position where the optical axis of the semiconductor laser element 12 and the optical axis of the lens 13 coincide. Acrylic and epoxy adhesives are preferred as ultraviolet-curable adhesives. Furthermore, a thermosetting adhesive, specifically an epoxy adhesive, is preferred, as this adhesive can suppress expansion or contraction due to heat generated when the semiconductor laser element 12 is driven, thereby preventing misalignment of the lens 13, which has been adjusted relative to the optical axis of the semiconductor laser element 12.

[0019] Regardless of the shape of the lens 13, it is preferable that the first bonding material 14 fixes two locations of the lens 13, namely, the lens side surface 13ff and another lens side surface 13ff located farthest from the lens side surface 13ff and sandwiching the optical axis (A in FIGS. 1D and 1F) of the lens 13, and two protrusions. That is, when the lens 13 is fixed to two protrusions 11b as shown in FIG. 1D, it is preferable that the two lens side surfaces 13ff of the lens 13 located on either side of a line (e.g., line J) that passes through the optical axis A of the lens 13 and is perpendicular to the first main surface of the flat portion 11a of the substrate 11 are fixed by the first bonding material 14. It is more preferable that two regions of the lens 13 that are line-symmetrical with respect to line J are fixed to the two protrusions 11b by the first bonding material 14. 1D , the lens 13 is fixed to the two protrusions 11b with the first bonding material 14 at two locations: a region R including one of two intersections M between the periphery of the lens 13 and a line JJ that passes through the optical axis A of the lens 13, is parallel to the first main surface of the flat plate portion 11a of the substrate 11, and is perpendicular to the optical axis of the semiconductor laser element 12; and the other region R including the other intersection M. Fixing the lens 13 with the first bonding material 14 in this manner makes it possible to efficiently offset the force caused by thermal expansion or contraction of the first bonding material 14 in the horizontal direction, that is, on the left and right, and makes it possible to more effectively suppress deviation of the optical axis of the laser light with respect to the lens 13. Region R can be set to any size and shape so as to include intersection M. For example, the length of region R in the height direction of protrusion 11b can be 20% to 100% of the length of one side of lens 13, and preferably 40% to 90%. Furthermore, the length of region R in the optical axis direction of semiconductor laser element 12 can be equal to or shorter than the length of lens 13 in the thickness direction (see, for example, FIG. 1F). It is preferable that the two regions R are the same size.

[0020] From another perspective, when the lens 13 is fixed to the two protrusions 11b, if the lens 13 has a side surface 13d other than the lens surface 13a, which is a side surface 13dd facing the flat portion 11a of the substrate 11, it is preferable to arrange the first bonding material 14 on the surface other than the side surface 13dd. For example, when the protrusion 11b has a side surface 13ff that is the side surface 13d and is parallel to the side surface 11ee, the first bonding material 14 is preferably disposed on the side surface 13ff. In this case, however, although a part of the first bonding material 14 may be disposed on the side surface 13dd, it is preferable that the first bonding material 14 does not come into contact with any members other than the protrusion 11b and the lens 13.

[0021] A part of the first bonding material 14 may be disposed on the upper surface 11bb of the protrusion 11b, the side surface 11aa on the semiconductor laser element 12 side, and / or the side surface 11cc opposite to the side surface 11aa on the semiconductor laser element 12. In particular, it is more preferable that the first bonding material 14 be disposed only on the side surface 11ee, as shown in FIG. 1D .

[0022] Furthermore, as shown in FIG. 1D, the first bonding material 14 preferably bonds the side surface 11ee of the protrusion 11b and the side surface 13ff of the lens 13 together. By bonding the lens 13 to the two protrusions 11b with the first bonding material 14, even if the bonding material thermally expands or contracts, offsetting forces act at the two points where the two protrusions 11b and the lens 13 are bonded, thereby suppressing misalignment of the optical axis of the semiconductor laser element 12 with respect to the lens 13. When an ultraviolet-curing bonding material is used as the first bonding material 14, if the bonding material is disposed on the side of the lens 13 rather than below it, it is possible to prevent the lens 13 from blocking ultraviolet light irradiated to cure the first bonding material 14. It is also possible to easily irradiate the lens 13 with ultraviolet light from above, facilitating active alignment. Furthermore, by disposing the bonding material on the side in the X direction where the FFP spreads less, that is, in the X direction where the FFP spreads less, it is possible to suppress the bonding material from spreading on the optical path when a large amount of bonding material is used.

[0023] 1A to 1D may further include a lid 16 for hermetically sealing the semiconductor laser element 12, as shown in Fig. 1E. The lid 16 may seal the submount 15, metal portions 11g and 11h, etc., as long as it can hermetically seal the semiconductor laser element 12, and may also seal the lens 13, protrusion 11b, etc. Such hermetic sealing can prevent dust from being collected from the atmosphere or the bonding agent. The lid 16 may be made of the same material as the substrate 11, or may be made of a different material. The entire lid 16 may be made of the same material, or a portion of the lid 16 may be made of a light-transmitting material such as quartz glass or sapphire, or the lid 16 may have metal parts or the like that can form a bonding material or a wiring layer on the inside or outside. Here, light-transmitting means that the transmittance of the light emitted from the semiconductor laser element 12 is 60% or more, preferably 70% or more, and more preferably 80% or more. The shape of the lid 16 may be any of a circle, an ellipse, a polygon such as a square or a pentagon, or a combination of these in a plan view, but a square is preferable. The lid 16 may have a shape with a recess or may be flat. The lid 16 is preferably bonded to the substrate 11 using the same material as the second bonding material.

[0024] <Embodiment 2> 2A to 2D for describing an exemplary embodiment, light source device 20 of Embodiment 2 includes a substrate 11, at least one semiconductor laser element 12 arranged on the substrate 11, and at least one lens 13 arranged on the light emission side of semiconductor laser element 12. Substrate 11 has a flat plate portion 11a and at least two protrusions 11b. Lens 13 is fixed to two protrusions 11b at at least two locations by a first bonding material 14. The difference between the light source device 20 and the light source device 10 is the position where the first bonding material 14 is disposed and the position of the lens 13 relative to the protrusion 11b, but other than that, the light source device 20 has substantially the same configuration as the light source device 10.

[0025] As shown in FIG. 2B, the first bonding material 14 fixes the lens surface 13a and the surface 13c opposite the lens surface 13a at two locations, namely, a portion near the side surface 13ff of the lens 13, and a portion near the side surface 13ff of another lens 13 located farthest from the side surface 13ff of the lens 13 across the optical axis of the lens 13, and two protrusions 11b. That is, when the protrusion 11b has a columnar shape, the first bonding material 14 is adjacent to the parallel side surfaces 11ee across the light emitted from the semiconductor laser element 12, and is disposed on the side surface 11cc opposite to the semiconductor laser element 12. In other words, the width of the lens 13 in the X direction is smaller than the width K between the protrusions 11b. The first bonding material 14 is disposed on the surface 13c opposite to the lens surface 13a. That is, the first bonding material 14 is disposed in a region where the lens 13 and the protrusion 11b overlap in a front view. In this case, a part of the first bonding material 14 may also be disposed on the side surface 13ff of the lens 13 that is parallel to the side surface 11ee of the protrusion 11b (that is, the surface that is perpendicular to the flat plate portion 11a of the substrate 11). The first bonding material 14 is preferably disposed only on the surface 13c opposite to the lens surface 13a and the side surface 13ff of the lens 13. The first bonding material 14 is preferably disposed in equal amounts on each of the two protrusions 11b. With this configuration, similarly to the light source device 10, the lens 13, which is positioned and fixed relative to the optical axis of the light emitted from the semiconductor laser element 12, can be prevented from shifting even if the first bonding material expands or contracts due to heat caused by driving the semiconductor laser element 12. Furthermore, compared to the first embodiment, the lens 13 and the protrusion 11b can be made smaller in the X direction.

[0026] <Embodiment 3> 3A to 3D for explaining an exemplary embodiment, a light source device 30 of the third embodiment includes a substrate 31, at least one semiconductor laser element 12 arranged on the substrate 31, and at least one lens 33 arranged on the light emission side of the semiconductor laser element 12. The substrate 31 has a flat plate portion 31a and at least two protrusions 31b. The lens 33 is fixed to the protrusion 31b at at least two locations by a first bonding material 14. The light source device 30 differs from the light source device 10 in the shape of the substrate 31 and the position of the first bonding material 14 in the lens 33, but other than that, the light source device 30 has substantially the same configuration as the light source device 10.

[0027] The substrate 31 has a flat plate portion 31a on which the semiconductor laser element 12 is mounted and two protrusions 31b. The top surface of the flat plate portion 31a and the top surface 31bb of the protrusions 31b are connected, and the top surfaces of the flat plate portion 31a and the top surfaces 31bb of the protrusions 31b are at the same or approximately the same height. Here, the "top surface" refers to a plane that intersects with the Z axis when the surface of the flat plate portion 31a is defined as an XY plane, and is preferably a plane that is perpendicular to the Z axis. "Same height" refers to the distance in the Z axis direction from the XY plane that forms the second main surface of the substrate 31, and "approximately the same height" means that a difference in height of ±10% is allowed. However, as long as the lens 33 can be fixed to the protrusions 31b at at least two points, the top surfaces of the flat plate portion 31a and the protrusions 31b may have a difference in height, or one of the top surfaces may be higher than the other. The substrate 31 has a recess 31d between the protrusions 31b. Therefore, the depth of the recess 31d corresponds to the height H3 of the protrusions 31b. By disposing a portion of the lens 33 in the recess 31d, the lens 33 can be fixed to at least two locations on the two protrusions 31b by the first bonding material 14. The size and depth of the recess 31d can be set to a size and depth that allows a part or all of the lens 33 to be placed therein, and can be appropriately set depending on the size of the lens 33 to be used, the size of the intended light source device, and the like. For example, the size of the recess 31d can be larger than that of the lens 33 in a plan view. The recess 31d may be provided from a position closer to the semiconductor laser element 12 than the surface 33c opposite to the lens surface 33a of the lens 33 to a position farther from the semiconductor laser element 12 than the lens surface 33a of the lens 33. Specifically, the depth of the recess 31d, i.e., the height H3 of the protrusion 31b, can be 0.2 mm or more and 2.0 mm or less. In this case, a part of the lens 33 may be placed protruding from the recess 31d (i.e., the upper surface 31bb of the protrusion 31b).

[0028] 3D , the first bonding material 14 fixes both sides of the optical axis A of the lens 33. In other words, in a plan view, the lens 33 is fixed by the first bonding material 14 on both sides of a line that passes through the optical axis A of the lens 33 within the lens 33 and is perpendicular to the surface of the flat plate portion 31 a of the substrate 31. In particular, the first bonding material 14 fixes the side surface 31ee where the two protrusions 31b face each other and the side surface 33ff of the lens 33, which is the side surface 33d of the lens 33 and is parallel to the side surface 31ee of the protrusions 31b. It is more preferable that the first bonding material 14 be disposed only on the side surface 31ee of the protrusions 31b and the lens 33. The first bonding material 14 also fixes the side surface 31 ee of the protrusion 31 b and the lens 33 at a position lower than the optical axis of the semiconductor laser element 12 . With this configuration, similarly to the light source device 10, the lens 33, which is positioned and fixed relative to the optical axis of the light emitted from the semiconductor laser element 12, can be prevented from shifting position even if the first bonding material expands or contracts due to heat caused by driving the semiconductor laser element 12. Furthermore, since the recess has a shape that encases the lens 33, the lens 33 can be easily protected.

[0029] <Embodiment 4> 4A to 4D, which illustrate an exemplary embodiment, a light source device 40 of the fourth embodiment includes a substrate 41, at least one semiconductor laser element 12 disposed on the substrate 41, and at least one lens 33 disposed on the light emission side of the semiconductor laser element 12. The substrate 41 has a flat plate portion 41a, at least two protrusions 41b1, and at least two protrusions 41b2 disposed on the protrusion 41b1. The lens 33 is fixed to the protrusions 41b1 and 41b2 at at least two locations by a first bonding material 14. The light source device 40 differs from the light source device 30 in the shape of the substrate 41 and the position of the first bonding material 14 in the lens 33, but other than that, the light source device 40 has substantially the same configuration as the light source device 30. Similar to the substrate 31 described above, the substrate 41 has a recess 41d in an area adjacent to the flat portion 41a, but also has protrusions 41b2 on both sides of the recess 41d in addition to the protrusions 41b1. The size and depth of the recess 41d and the heights of the protrusions 41b1 and 41b2 can be set to a size, depth, and height that allows for placement of part or all of the lens 33, and can be set appropriately depending on the size of the lens 33 used, the size of the intended light source device, and the like. For example, the total height H4 of the protrusions 41b1 and 41b2 can be 0.5 mm or more and 5.0 mm or less. The opposing side surfaces 41ee1, 41ee2 of the protrusions 41b1, 41b2 do not have to be arranged so as to form the same plane, but it is preferable that they do. The width of the protrusion 41b2 in the Y direction can be, for example, 80% to 120% of the width of the lens 33 in the Y direction, and is preferably 100% or less. Therefore, by disposing a portion of the lens 33 between the two opposing protrusions 41b1 and / or the two opposing protrusions 41b2, the lens 33 can be fixed to the protrusions 41b1 and 41b2 at at least two locations by the first bonding material 14. In this case, the first bonding material 14 may be disposed only on the opposing side surfaces 41ee1 of the protrusions 41b1, or may be disposed only on the opposing side surfaces 41ee2 of the protrusions 41b2, or may be disposed so as to be connected to the opposing side surfaces 41ee1 and 41ee2 of the protrusions 41b1 and 41b2. With this configuration, similar to the light source device 30, the lens 33, which is positioned and fixed relative to the optical axis of light emitted from the semiconductor laser element 12, can be prevented from shifting position even if the first bonding material expands or contracts due to heat caused by driving the semiconductor laser element 12. Furthermore, if the width of the protrusion 41b2 in the Y direction is smaller than the width of the lens 33 in the Y direction, it is possible to prevent the first bonding material from adhering to the lens surface 33a. Furthermore, the provision of the protrusions 41b1 and 41b2 makes it possible to hold the lens 33 more firmly.

[0030] <Embodiment 5> As shown in FIGS. 5A to 5D for illustrating an exemplary embodiment, a light source device 50 of the fifth embodiment includes a substrate 51, a plurality of, for example, three semiconductor laser elements 12 arranged on the substrate 51, and a plurality of, for example, three lenses 13 arranged on the light-emitting sides of the semiconductor laser elements 12. The spacing between adjacent semiconductor laser elements 12 is, for example, 0.2 mm to 5.0 mm. The substrate 51 has a flat plate portion 51a and a plurality of, for example, four protrusions 51b. The lenses 13 are fixed at at least two locations to two adjacent protrusions 51b by a first bonding material 14. The adjacent lenses 13 are fixed by sharing the protrusion 51b arranged between them. Other than the above-mentioned configuration, the light source device has substantially the same configuration as the light source device 10. With this configuration, similar to the light source device 10, the lens 13, which is fixed after being positioned relative to the optical axis of the light emitted from the semiconductor laser element 12, can be prevented from shifting position even if the first bonding material expands or contracts due to heat caused by driving the semiconductor laser element 12. Furthermore, by fixing adjacent lenses 13 by sharing the protrusion 51b disposed between them, space can be saved within the light source device, and the optical device can be made more compact.

[0031] <Embodiment 6> 6A to 6D, which illustrate an exemplary embodiment, the light source device of Embodiment 6 includes a substrate 61, a plurality of, for example, four semiconductor laser elements 12 arranged on the substrate 61, and a plurality of, for example, four lenses 13 arranged on the light emission sides of the semiconductor laser elements 12. The semiconductor laser elements 12 include a semiconductor laser element 12a that emits red light, a semiconductor laser element 12b that emits green light, a semiconductor laser element 12c that emits blue light, and a semiconductor laser element 12d that emits infrared light. The order of these elements in parallel can be set arbitrarily. Other than the above-described configuration, the light source device 50 has substantially the same configuration. With this configuration, similar to the light source devices 10 and 50, the lens 13, which is fixed after being positioned relative to the optical axis of the light emitted from the semiconductor laser element 12, can be prevented from shifting position even if the first bonding material expands or contracts due to heat caused by driving the semiconductor laser element 12. Furthermore, by fixing adjacent lenses 13 by sharing the protrusion 51b disposed between them, space can be saved within the light source device, and the overall size of the device can be reduced.

[0032] <Embodiment 7> 7A and 7B for explaining an exemplary embodiment, a light source device 70 of Embodiment 7 includes a substrate 71, at least one semiconductor laser element 12 arranged on the substrate 71, a reflecting member 77 that reflects light emitted from the semiconductor laser element 12, and at least one lens 73 arranged in the traveling direction of the light reflected by the reflecting member 77. The substrate 71 has a flat plate portion 71a and a protruding portion 71b. The lens 73 is fixed to the protruding portion 71b by a first bonding material 14. The light source device 70 differs from the light source device 10 in that the shape of the substrate 71, the shape of the lens 73, the presence of a reflecting member 77, and the traveling direction of the light from the semiconductor laser element 12 are different. The substrate 71 has a flat plate portion 71a on which the semiconductor laser element 12 is disposed and a sidewall 71k surrounding the flat plate portion 71a. That is, the substrate 71 has a recess 71L formed by the flat plate portion 71a and the sidewall 71k, and a protrusion 71b is formed above the sidewall 71k. The protrusion 71b has a protrusion 71bx having a side surface intersecting the traveling direction (Y direction) of the light emitted from the semiconductor laser element 12, and a protrusion 71by having a side surface approximately parallel to the traveling direction of the light emitted from the semiconductor laser element 12. In addition, a step 71ka is arranged inside the sidewall 71k. Lens 73 is adjusted so that the laser light reflected by reflecting member 77 passes through the optical axis of lens 73, and has lens surface 73a, surface 73c opposite lens surface 73a, side surface 73d in contact with surface 73c opposite lens surface 73a, and surface 73b in contact only with lens surface 73a and side surface 73d. The lens 73 may be fixed at four locations each on the two protrusions 71bx and two protrusions 71by by the first bonding material 14x, 14y, for a total of eight locations, or may be fixed at four locations on the two protrusions 71bx by the first bonding material 14x only, or may be fixed at four locations on the two protrusions 71by by the first bonding material 14y only. A reflecting member 77 is disposed on the flat plate portion 71a of the substrate 71 on the light emission side of the semiconductor laser element 12. The reflecting member 77 has a light-reflecting surface 77a that reflects light. That is, the reflecting member 77 has a light-reflecting surface 77a that reflects light that is emitted from the semiconductor laser element 12 and enters the reflecting member 77 upward, i.e., in the Z-axis direction. The light-reflecting surface 77a is inclined with respect to the flat plate portion 71a. For example, the light-reflecting surface 77a can be provided as an inclined surface that has an inclination angle of approximately 45 degrees with respect to the flat plate portion 71a. The reflecting member 77 can be formed mainly using glass such as quartz or BK7 (borosilicate glass), metal such as aluminum, Si, etc. On the light reflecting surface 77a, for example, a metal such as Ag or Al, or a dielectric multilayer film such as Ta2O5 / SiO2, TiO2 / SiO2, or Nb2O5 / SiO2 can be formed. The light reflecting surface has a light reflectance of 90% or more with respect to the peak wavelength of the light to be reflected, preferably 95% or more, and more preferably 99% or more. The substrate 71 has a lid 76 for hermetically sealing the semiconductor laser element 12 and the like disposed above the semiconductor laser element 12 and a reflecting member 77. The lid 76 can be fixed by utilizing a step 71ka. By having such a configuration, similar to the light source device 10, the lens 73, which is positioned and fixed relative to the optical axis of the light emitted from the semiconductor laser element 12, can suppress misalignment even if the first bonding material expands or contracts due to heat caused by driving the semiconductor laser element 12.

[0033] (Variation) 7C, which illustrates an exemplary modification of light source device 70 of Embodiment 7, light source device 70A has a step 71kb disposed on the inner step 71ka of sidewall 71k, and lens 73 is fixed to the top of step 71kb. Other than this, it has substantially the same configuration as the light source device 70 and has the same effects. [Industrial Applicability]

[0034] The light emitting device according to each embodiment can be used in projectors, vehicle headlights, head-mounted displays, lighting, displays, and the like. [Explanation of symbols]

[0035] 10, 20, 30, 40, 50, 60, 70, 70A light source device 11, 31, 41, 51, 61, 71 boards 11a, 31a, 41a, 51a, 61a, 71a Flat plate part 11b, 31b, 41b, 41b1, 41b2, 51b, 61b, 71b, 71bx, 71by protrusion 11aa, 11cc, 11ee, 31ee, 41ee1, 41ee2 Side 11bb, 31bb, 41bb top surface 11g, 11h metal part 31d, 41d, 71L recess 71k side wall 71ka, 71kb step 12 Semiconductor laser element 12a Semiconductor laser element that emits red light 12b Semiconductor laser element emitting green light 12c Semiconductor laser element that emits blue light 12d Semiconductor laser element that emits infrared light 13, 33, 73 lenses 13a, 33a, 73a lens surface 13b, 73b Surfaces that only contact the lens surface 13c, 33c, 73c Lens surface and opposite surface 13d, 13dd, 13ff, 33d, 33ff, 73d side 14, 14x, 14y 1st joint material 15 Submount 16, 76 Lid 77 Reflective material 77a Light reflective surface

Claims

1. A substrate; at least one semiconductor laser element disposed on the substrate; at least one lens disposed on the light emission side of the semiconductor laser element; the substrate has a flat plate portion for mounting the semiconductor laser element thereon, and at least two protrusions disposed on both sides of the semiconductor laser element and on the light emitting side; The upper surface of the protrusion is connected to the upper surface of the flat plate portion, and the height of the upper surface of the protrusion and the upper surface of the flat plate portion are substantially the same, except that the protrusion extends directly below the lens, The lens is fixed to the two protrusions at at least two points by a first bonding material, and is fixed in contact with only the two protrusions via the first bonding material.

2. 2. The light source device according to claim 1, wherein the substrate is made of ceramic.

3. The light source device according to claim 1 , wherein the protrusion is integrally formed with the flat plate portion.

4. 4. The light source device according to claim 1, wherein the semiconductor laser element is disposed on the flat plate portion via a submount.

5. 5. The light source device according to claim 4, wherein the semiconductor laser element or the submount is fixed by a second bonding material having a linear expansion coefficient smaller than that of the first bonding material.

6. The light source device according to claim 1 , wherein the first bonding material is an ultraviolet curable or heat curable bonding material.

7. a plurality of the semiconductor laser elements are provided, the lenses are provided in the same number as the plurality of semiconductor laser elements, and are disposed on the light emission sides of the corresponding plurality of semiconductor laser elements, the protrusions are provided at positions that sandwich the lenses, respectively; The light source device according to claim 1 , wherein at least one of the plurality of protrusions is in contact with two of the lenses via the first bonding material.

8. The number of the semiconductor laser elements provided is three or more, 8. The light source device according to claim 7, wherein at least one of the plurality of semiconductor laser elements emits red light, at least one emits green light, and at least one emits blue light.

9. The number of the semiconductor laser elements provided is four or more, 9. The light source device according to claim 8, wherein at least one of the plurality of semiconductor laser elements emits red light, at least one emits green light, at least one emits blue light, and at least one emits infrared light.

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