Method for manufacturing a laser light source

Abstract

To provide a laser light source which is less likely to cause positional deviation between a laser diode chip and a lens.SOLUTION: A method for manufacturing a laser light source includes the steps of: preparing a submount including a principal plane fixed with a laser diode chip having an emission surface and a pair of lens support parts located on both sides of the emission surface of the laser diode chip; preparing a lens; adjusting an end surface of the pair of lens support parts in the submount in parallel to a reference surface; adjusting a bonding surface of the lens in parallel to the reference surface; and joining the end surface of the pair of lens support parts and the bonding surface of the lens with an inorganic joining material with the end surface of the pair of lens support parts and the bonding surface of the lens kept in parallel to the reference surface.SELECTED DRAWING: Figure 2A

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a laser light source.

Background Art

[0002] Laser light sources are used in various applications such as processing, projectors, and lighting fixtures. A typical example of such a laser light source includes a laser diode chip, a submount that supports the laser diode chip, and a collimating lens that reduces the divergence angle of the laser light emitted from the laser diode chip (for example, Patent Document 1). When lenses such as a laser diode chip, a submount, and a collimating lens are housed in a semiconductor laser package, it becomes possible to collimate the laser light with a small lens before the laser light diverges significantly. On the other hand, due to a slight misalignment between the laser diode chip and the lens, the direction of the optical axis of the laser light emitted from the laser light source to the outside may shift significantly.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a demand for a laser light source in which misalignment between a laser diode chip and a lens is less likely to occur.

Means for Solving the Problems

[0005] In one embodiment, a method for manufacturing a laser light source according to the present disclosure includes a step of preparing a submount having a main plane to which a laser diode chip having an emission surface is fixed, and a pair of lens support portions located on both sides of the emission surface of the laser diode chip, a step of preparing a lens having a bonding surface, a step of adjusting end faces of the pair of lens support portions in the submount to be parallel to a reference plane, a step of adjusting the bonding surface of the lens to be parallel to the reference plane, and a step of bonding the end faces of the pair of lens support portions and the bonding surface of the lens with an inorganic bonding material while maintaining the end faces of the pair of lens support portions and the bonding surface of the lens parallel to the reference plane. And a step of bonding the end faces of the pair of lens support portions and the bonding surface of the lens with an inorganic bonding material.

Advantages of the Invention

[0006] According to the present disclosure, it is possible to realize a laser light source in which misalignment between a laser diode chip and a lens is less likely to occur.

Brief Description of the Drawings

[0007]

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Mode for Carrying Out the Invention

[0008] Hereinafter, with reference to the drawings, the laser light source in the embodiment of the present disclosure will be described in detail. Parts denoted by the same reference numerals in a plurality of drawings indicate the same or equivalent parts.

[0009] Furthermore, the following is an exemplification for embodying the technical idea of the present disclosure, and the present disclosure is not limited thereto. In addition, the description of the dimensions, materials, shapes, relative arrangements, etc. of the components is not intended to limit the scope of the present disclosure only thereto, but is intended to be an exemplification. The sizes and positional relationships of the members shown in each drawing may be exaggerated for ease of understanding.

[0010] (Embodiment 1) First, with reference to FIGS. 1A to 2C, a basic configuration example of the laser light source in Embodiment 1 of the present disclosure will be described.

[0011] FIG. 1A is a perspective view schematically showing a configuration example of a laser light source 100 in Embodiment 1 of the present disclosure. FIG. 1B is a diagram schematically showing a planar configuration of the laser light source 100 of FIG. 1A. The laser light source 100 in the present embodiment includes a laser diode chip 10, a submount 20 that supports the laser diode chip 10, a collimating lens 30 supported by the submount 20, and a semiconductor laser package 40 that houses these elements or components. Further, the laser light source 100 in the present embodiment includes a pair of lead terminals 50 that penetrate the semiconductor laser package 40 and supply power to the laser diode chip 10. The semiconductor laser package 40 includes a lid body 40L, a base body 40b, and a light-transmitting window 40w. In the laser light source 100 in the present embodiment, laser light emitted from the laser diode chip 10 and collimated by the collimating lens 30 is taken out to the outside through the light-transmitting window 40w.

[0012] In FIG. 1A, for ease of explanation, the lid body 40L, the base body 40b, and the light-transmitting window 40w in the semiconductor laser package 40 are shown in a separated state, but actually they are joined. In FIG. 1B, the description of the lid body 40L in the semiconductor laser package 40 is omitted.

[0013] In the drawings, for reference, the X-axis, Y-axis, and Z-axis orthogonal to each other are schematically shown. For ease of explanation, in the present disclosure, the side where the laser diode chip 10, the submount 20, and the collimating lens 30 are located within the base body 40b may be expressed as "up". This does not limit the orientation of the laser light source 100 during use, and the orientation of the laser light source 100 is arbitrary.

[0014] FIG. 2A is a perspective view showing more details of a configuration in which the semiconductor laser package 40 and the pair of lead terminals 50 are omitted from the laser light source 100 of FIG. 1A. The region surrounded by the dashed line in FIG. 2A represents an example of the detailed structure of the laser diode chip 10 disposed on the submount 20. In FIG. 2A, the submount 20 and the collimating lens 30 are shown in a separated state, but in reality, they are joined. FIG. 2B is a top view schematically showing the laser light source 100 of FIG. 2A. FIG. 2C is a cross-sectional view taken along the IIC-IIC line parallel to the YZ plane of the configuration of FIG. 2B. In the present disclosure, with reference to the submount 20, the side where the collimating lens 30 is located may be expressed as “front”.

[0015] As shown in FIG. 2A, the laser diode chip 10 is an end-face emitting type laser diode chip, and includes a semiconductor laminate structure 10a including a first cladding layer 10C1, a second cladding layer 10C2, and a light emitting layer 10L, a substrate 10b supporting the semiconductor laminate structure 10a, an emission surface 10e1 for emitting the high-power laser light generated in the light emitting layer 10L, and a rear surface 10e2 on the side opposite to the emission surface 10e1. The light emitting layer 10L is located between the first cladding layer 10C1 and the second cladding layer 10C2. The laser diode chip 10 may include other layers such as a buffer layer and a contact layer.

[0016] The laser diode chip 10 is fixed to the submount 20 in a face-down state where the light-emitting layer 10L is closer to the submount 20 than the substrate 10b. The total size in the Y direction of the semiconductor laminate 10a and the substrate 10b in the laser diode chip 10 is about 80 μm. The total size in the Y direction of the substrate 10b and the first cladding layer 10C1 is larger than the size in the Y direction of the second cladding layer 10C2. In the face-down state, the distance between the light-emitting layer 10L and the submount 20 is about one-tenth compared to the face-up state where the light-emitting layer 10L is farther from the submount 20 than the substrate 10b. Therefore, in the face-down state, even when high-output laser light is emitted from the light-emitting layer 10L, the heat generated in the light-emitting layer 10L can be efficiently transmitted to the submount 20. The output of the laser light in this embodiment is, for example, 3 W or more and 50 W or less.

[0017] The semiconductor laminate structure 10a may have, for example, a double heterostructure that forms the energy levels of a quantum well. The bandgap of the light-emitting layer 10L is smaller than the bandgaps of the first cladding layer 10C1 and the second cladding layer 10C2. In the present embodiment, the substrate 10b and the first cladding layer 10C1 on the substrate 10b may each be formed of an n-type semiconductor. The light-emitting layer 10L may be formed of an intrinsic semiconductor, an n-type semiconductor, or a p-type semiconductor, and the second cladding layer 10C2 on the light-emitting layer 10L may be formed of a p-type semiconductor. The n-type and p-type may be reversed. By injecting current from the p-type cladding layer to the n-type cladding layer, an inverted distribution of carriers occurs in the light-emitting layer 10L, and light is induced and emitted from the light-emitting layer 10L. The refractive index of the light-emitting layer 10L is designed to be higher than the refractive indices of the first cladding layer 10C1 and the second cladding layer 10C2, and the light generated in the light-emitting layer 10L is confined within the light-emitting layer 10L by total reflection. The light-emitting layer 10L functions as a resonator, and laser light is emitted from the emission surface 10e1 of the light-emitting layer 10L. The resonator length of the light-emitting layer 10L is defined by the distance from the emission surface 10e1 to the rear surface 10e2. The direction of the resonator length is parallel to the Z direction. The resonator length is, for example, 500 μm or more and 5000 μm or less. When the resonator length is long, the contact area between the laser diode chip 10 and the submount 20 can be increased, so that the heat generated in the light-emitting layer 10L can be efficiently transferred to the submount 20.

[0018] The laser light emitted from the emission surface 10e1 of the laser diode chip 10 diverges rapidly in the YZ plane and slowly in the XZ plane as it propagates. The spot of the laser light, when not collimated, has an elliptical shape in the far field in the XY plane, with the Y direction as the major axis and the X direction as the minor axis.

[0019] The laser diode chip 10 can emit purple, blue, green or red laser light in the visible region, or infrared or ultraviolet laser light. The emission peak wavelength of the purple light is desirably in the range of 350 nm or more and 419 nm or less, and more desirably in the range of 400 nm or more and 415 nm or less. The emission peak wavelength of the blue light is desirably in the range of 420 nm or more and 494 nm or less, and more desirably in the range of 440 nm or more and 475 nm or less. Examples of the semiconductor laser element that emits purple or blue laser light include semiconductor laser elements containing a nitride semiconductor. As the nitride semiconductor, for example, GaN, InGaN, and AlGaN can be used. The emission peak wavelength of the green light is desirably in the range of 495 nm or more and 570 nm or less, and more desirably in the range of 510 nm or more and 550 nm or less. Examples of the semiconductor laser element that emits green laser light include semiconductor laser elements containing a nitride semiconductor. As the nitride semiconductor, for example, GaN, InGaN, and AlGaN can be used. The emission peak wavelength of the red light is desirably in the range of 605 nm or more and 750 nm or less, and more desirably in the range of 610 nm or more and 700 nm or less. Examples of the semiconductor laser element that emits red laser light include semiconductor laser elements containing InAlGaP-based, GaInP-based, GaAs-based, and AlGaAs-based semiconductors. As the semiconductor laser element for red light, a semiconductor laser element having two or more waveguide regions can be used. The semiconductor laser element containing these semiconductors is more likely to have its output reduced by heat compared to the semiconductor laser element containing a nitride semiconductor. By increasing the number of waveguide regions, heat can be dispersed and the output reduction of the semiconductor laser element can be reduced.

[0020] The submount 20 has a main plane 20s1 to which the laser diode chip 10 is fixed, a pair of lens support portions 20LS located on both sides of the emission surface 10e1 of the laser diode chip 10, a back surface 20s2 located on the opposite side of the main plane 20s1, and a front end surface 20fe connecting the main plane 20s1 and the back surface 20s2. The main plane 20s1 and the front end surface 20fe define an edge 20ed of the main plane 20s1. In the example shown in FIG. 2A, the pair of lens support portions 20LS are a pair of convex portions located on both sides of the laser diode chip 10 and extending in the Z direction. The submount 20 has the following U-shaped configuration extending in the Z direction behind the front end surface 20fe. This U-shaped configuration is formed by dividing a rectangular tube body extending in the Z direction and mirror-symmetric with respect to a plane parallel to the YZ plane by a plane parallel to the XZ plane. The end surface 20se of the pair of lens support portions 20LS protrudes in the resonator length direction from the emission surface 10e1 of the laser diode chip 10. The normal direction of the main plane 20s1 is parallel to the Y direction.

[0021] The distance in the Z direction between the end surface 20se of the pair of lens support portions 20LS and the emission surface 10e1 of the laser diode chip 10 can be designed to be approximately equal to the focal length of the collimating lens 30. The distance in the Z direction between the end surface 20se of the pair of lens support portions 20LS and the emission surface 10e1 of the laser diode chip 10 is, for example, 50 μm or more and 100 μm or less. The size of the pair of lens support portions 20LS in the Y direction can be on the same order as the size of the collimating lens 30 in the Y direction. The size of the pair of lens support portions 20LS in the Y direction may be larger than, equal to, or smaller than the size of the collimating lens 30 in the Y direction. The size of the pair of lens support portions 20LS in the Y direction is, for example, 100 μm or more and 500 μm or less.

[0022] The size of the submount 20 in the X direction is, for example, 1 mm or more and 3 mm or less. Among the submount 20, the size of the portion other than the pair of lens support portions 20LS in the Y direction is, for example, 100 μm or more and 500 μm or less, and the size of the portion other than the pair of lens support portions 20LS in the Z direction is, for example, 1 mm or more and 6 mm or less. In the present disclosure, the upper limit of the size can be determined from the viewpoint of miniaturization of the laser light source 100.

[0023] In the submount 20, the emission surface 10e1 of the laser diode chip 10 protrudes in the resonator length direction from the edge 20ed of the main plane 20s1. The distance in the Z direction between the emission surface 10e1 of the laser diode chip 10 and the edge 20ed of the main plane 20s1 is, for example, 2 μm or more and 50 μm or less. With this arrangement, even when the laser diode chip 10 and the main plane 20s1 of the submount 20 are fixed with a bonding material such as an inorganic material like AuSn in a face-down state, it is possible to suppress the bonding material from rising onto the emission surface 10e1 of the light-emitting layer 10L. In the laser light source disclosed in Patent Document 1, when the laser diode chip is arranged in a face-down state, the bonding material for bonding the laser diode chip and the submount may rise onto the emission surface 10e1 of the light-emitting layer in the laser diode chip. As a result, the output of the laser light emitted from the laser diode chip may decrease. In the laser light source 100 in the present embodiment, such a decrease in the output of the laser light can be suppressed.

[0024] Part or all of the submount 20 can be formed from, for example, a ceramic containing at least one selected from the group consisting of AlN, SiC, and alumina and an alloy such as CuW. The submount 20 can be produced, for example, by sintering ceramic powder. The thermal conductivity of the ceramic can be, for example, 10 [W / m·K] or more and 500 [W / m·K] or less. Also, in order to suppress deformation due to heat applied during the fixing of the laser diode chip 10, the ceramic can have a low coefficient of thermal expansion. The coefficient of thermal expansion is 2×10 -6 [1 / K] or more and 1×10-5 It can be less than [1 / K]. A metal film having a thickness of, for example, 0.5 μm or more and 10 μm or less may be formed on the main plane 20s1 and the back plane 20s2 of the submount 20. For example, Au plating can be performed on the main plane 20s1 and the back plane 20s2 of the submount 20. The laser diode chip 10 can be joined to the main plane 20s1 with, for example, AuSn by the metal film formed on the main plane 20s1. The submount 20 can be joined to the bottom 40b1 with, for example, AuSn by the metal film formed on the back plane 20s2.

[0025] The collimating lens 30 is a so-called FAC (Fast Axis Collimator) lens that collimates a component of the laser light emitted from the laser diode chip 10 that diverges greatly in the YZ plane. A so-called SAC (Slow Axis Collimator) lens (not shown) that collimates a component of the laser light that diverges slightly in the XZ plane can be disposed outside the laser light source 100 as necessary. In the present disclosure, "collimating" includes not only making the laser light parallel light but also reducing the divergence angle of the laser light. Depending on the application, other lenses such as a condenser lens may be used instead of the collimating lens 30.

[0026] The collimating lens 30 is a cylindrical lens having a structure extending in the X direction, having no curvature in the X direction, and having a curvature in the Y direction. The direction in which the collimating lens 30 extends is perpendicular to both the normal direction of the main plane 20s1 of the submount 20 and the resonator length direction. Since the sizes of the collimating lens 30 and the pair of lens support portions 20LS in the Y direction are about the same, it is easy to provide the center of gravity of the collimating lens 30 between the pair of lens support portions 20LS when viewed from the resonator length direction. Due to this positional relationship of the center of gravity of the collimating lens 30, the collimating lens 30 can be stably and more accurately provided on the submount 20.

[0027] In this embodiment, when the back surface 20s2 of the submount 20 is used as a reference, the height of the upper surfaces of the pair of lens support portions 20LS in the Y direction is substantially equal to the height of the upper surface of the collimating lens 30 in the Y direction. The position of the collimating lens 30 with respect to the pair of lens support portions 20LS is roughly adjusted so that the above two heights are substantially equal. Then, while emitting laser light from the laser diode chip 10, the position of the collimating lens 30 with respect to the pair of lens support portions 20LS is finely adjusted so that the laser light is properly collimated. Note that the above two heights do not necessarily have to be substantially equal and may be different.

[0028] Since the collimating lens 30 in this embodiment is uniform along the X direction, there is no need to consider the alignment in the X direction between the emission surface 10e1 of the laser diode chip 10 and the collimating lens 30. It is only necessary that only the opposing portion of the collimating lens 30 facing the emission surface 10e1 of the laser diode chip 10 and its peripheral portion be uniform along the X direction. Therefore, the other two side portions do not necessarily have to be uniform along the X direction and do not have to be transparent. The size of the two side portions of the collimating lens 30 in the Y direction may be larger than, equal to, or smaller than the size of the opposing portion and its peripheral portion in the Y direction. The collimating lens 30 can be formed from, for example, at least one of glass, quartz, synthetic quartz, sapphire, transparent ceramic, and plastic.

[0029] The collimating lens 30 is joined in the Z direction to the end faces 20se of the pair of lens support portions 20LS. Even if there is some variation in the thickness of the bonding material that joins the collimating lens 30 and the end faces 20se of the pair of lens support portions 20LS, that variation has almost no effect on the position of the collimating lens 30 in the Y direction. Different from the configuration of the present embodiment, it is also possible to arrange a pedestal having a plane parallel to the main plane 20s1 in front of the submount 20 and provide the collimating lens 30 on the plane of the pedestal. However, in such a configuration, if there is variation in the thickness of the bonding material between the collimating lens 30 and the plane of the pedestal, a misalignment in the Y direction may occur between the laser diode chip 10 and the collimating lens 30, and there is a possibility that the direction of the optical axis of the laser light emitted from the laser light source 100 to the outside will shift significantly. In contrast, in the present embodiment, it is less likely for a misalignment in the Y direction to occur between the laser diode chip 10 and the collimating lens 30, and the optical axis of the laser light emitted from the laser light source 100 to the outside can be directed in the designed direction. Even if there is some variation in the thickness of the bonding material, the position of the collimating lens 30 only changes slightly along the optical axis of the laser light, so that variation has almost no effect on the direction of the optical axis of the laser light.

[0030] The collimating lens 30 and the end faces 20se of the pair of lens support portions 20LS can be joined with a bonding material of an inorganic material such as AuSn, for example. A metal film may be formed in advance on the bonding surface of the collimating lens 30 and the end faces 20se of the pair of lens support portions 20LS. These metal films enable bonding with, for example, AuSn. The bonding temperature of AuSn is approximately 280°C. If the thermal conductivity of the ceramic forming the submount 20 is low, the influence of the heat applied to the bonding material during the joining of the end faces 20se of the pair of lens support portions 20LS and the collimating lens 30 on the laser diode chip 10 can be reduced.

[0031] As another example, the collimating lens 30 and the end face 20se of the pair of lens support portions 20LS can be joined with a bonding material containing a thermosetting resin. The bonding temperature of the thermosetting resin is about 100° C., which is lower than the bonding temperature of inorganic materials. Therefore, the influence of the heat applied to the bonding material when joining the end face 20se of the pair of lens support portions 20LS and the collimating lens 30 on the laser diode chip 10 can be further reduced. In the joining of the collimating lens 30 and the end face 20se of the pair of lens support portions 20LS, the thermosetting resin can be heated, for example, by irradiating the position of point P shown in FIG. 2A with laser light. The distance in the Z direction between the position of point P and the end face 20se of the pair of lens support portions 20LS is, for example, 50 μm or more and 500 μm or less. In the present embodiment, in a top view, since the optical axis of the laser light emitted from the laser diode chip 10 and the bonding material do not overlap, even if outgas is generated from the bonding material containing the thermosetting resin, it is possible to suppress the outgas from approaching the laser diode chip 10. As a result, it is possible to suppress the occurrence of dust collection described later on the emission surface 10e1 of the laser diode chip 10.

[0032] Some inorganic material bonding materials may contain an organic substance as a binder. Even when using such a bonding material for joining the collimating lens 30 and the end face 20se of the pair of lens support portions 20LS, it is possible to suppress the outgas generated by heating from approaching the laser diode chip 10.

[0033] In the laser light source 100 in the present embodiment, the submount 20 supports the laser diode chip 10 and the collimating lens 30. Since the distance between the emission surface 10e1 of the laser diode chip 10 and the collimating lens 30 is short, the divergence of the laser light emitted from the laser diode chip 10 can be reduced by the small collimating lens 30 before the laser light diverges significantly. Therefore, it becomes possible to realize a small-sized laser light source 100. Also, it becomes possible to reduce the diameter of the collimated beam that has passed through the collimating lens 30.

[0034] The semiconductor laser package 40 may hermetically seal the laser diode chip 10, the submount 20, and the collimating lens 30. When the laser diode chip 10 emits laser light with a short wavelength of, for example, 350 nm or more and 570 nm or less, organic gas components contained in the atmosphere may be decomposed by the laser light, and the decomposition products may adhere to the emission surface 10e1 of the laser diode chip 10. Further, if the emission surface 10e1 of the laser diode chip 10 is in contact with the outside air, the deterioration of the emission surface 10e1 may progress during operation due to dust collection or the like. Such deterioration of the emission surface 10e1 can cause a decrease in the optical output of the laser diode chip 10. In order to enhance the reliability of the laser diode chip 10 and extend its life, it is desirable that the semiconductor laser package 40 hermetically seals the laser diode chip 10. The hermetic sealing by the semiconductor laser package 40 may be performed regardless of the wavelength of the laser light emitted from the laser diode chip 10.

[0035] In the semiconductor laser package 40, the substrate 40b is in thermal contact with the back surface 20s2 of the submount 20. The substrate 40b can be formed of a material with high thermal conductivity. The material is, for example, a metal containing at least one selected from the group consisting of Cu, Al, Ag, Fe, Ni, Mo, Cu, W, and CuMo. In order to align the heights of the emission surface 10e1 of the laser diode chip 10 and the light-transmitting window 40w, as shown in FIG. 1B, a member 40m with high thermal conductivity may be provided between the bottom surface 40bt of the substrate 40b and the submount 20. The member 40m can be formed of the same material as the portion including the bottom surface 40bt of the substrate 40b. Alternatively, at least a part of the bottom surface 40bt of the substrate 40b may be raised, and the submount 20 may be disposed on the raised bottom surface 40bt. The portion including the bottom surface 40bt of the substrate 40b can be formed of, for example, copper. The portion of the substrate 40b surrounding the laser diode chip 10, the submount 20, and the collimating lens 30 can be formed of, for example, kovar. Kovar is an alloy obtained by adding nickel and cobalt to iron as the main component. The lid 40L in the semiconductor laser package 40 may be formed of the same material as the substrate 40b or may be formed of a different material. The light-transmitting window 40w in the semiconductor laser package 40 is attached to the substrate 40b and transmits the laser light emitted from the laser diode chip 10. The light-transmitting window 40w in the semiconductor laser package 40 can be formed of, for example, at least one of glass, quartz, synthetic quartz, sapphire, transparent ceramic, and plastic, similar to the collimating lens 30.

[0036] The pair of lead terminals 50 are each electrically connected to the laser diode chip 10 by wires as follows. In the example shown in FIG. 2A, a metal film is formed on the upper surface of the laser diode chip 10. The metal film and one of the pair of lead terminals 50 are electrically connected by a wire. Similarly, a metal film is also formed on the main plane 20s1 of the submount 20. The metal film and the other of the pair of lead terminals 50 are electrically connected by a wire. For example, the upper surface of the laser diode chip 10 and the main plane 20s1 of the submount 20 can be subjected to Au plating. A current is injected from the pair of lead terminals 50 into the first cladding layer 10C1 from the second cladding layer 10C2 in the laser diode chip 10. The pair of lead terminals 50 are electrically connected to an external circuit (not shown) that adjusts the emission timing and output of the laser light emitted from the laser diode chip 10. The pair of lead terminals 50 are formed of a material with good conductivity. Examples of such materials include metals such as Fe-Ni alloys or Cu alloys.

[0037] In the laser light source 100 according to the present embodiment, the submount 20 supports the laser diode chip 10 by the main plane 20s1 between the pair of lens support portions 20LS, and supports the collimating lens 30 by the end faces 20se of the pair of lens support portions 20LS. Thereby, as described above, the alignment between the laser diode chip 10 and the collimating lens 30 becomes easy, and it becomes possible to realize a small-sized laser light source 100. Further, in the laser light source 100 according to the present embodiment, even when the laser diode chip 10 is arranged in a face-down state on the submount 20, it is possible to suppress the bonding material from rising onto the emission surface 10e1 of the laser diode chip 10.

[0038] (Modification Example 1 of Embodiment 1) Next, modification examples 1 to 7 of the laser light source 100 according to Embodiment 1 of the present disclosure will be described. In the following modification examples, the description of the semiconductor laser package 40 and the pair of lead terminals 50 is omitted. Descriptions that overlap with the above may be omitted.

[0039] Referring to FIGS. 3A to 3C, a configuration example of the laser light source 110 in Modification 1 of Embodiment 1 of the present disclosure will be described. FIG. 3A is a perspective view schematically showing a configuration example of the laser light source 110 in Modification 1 of Embodiment 1 of the present disclosure. FIG. 3B is a top view schematically showing the laser light source 110 of FIG. 3A. FIG. 3C is a cross-sectional view taken along line IIIC-IIIC parallel to the YZ plane of the configuration of FIG. 3B. The difference between the laser light source 110 in Modification 1 of Embodiment 1 and the laser light source 100 in Embodiment 1 is the shape of the submount 20. The front end face 20fe of the submount 20 has a central end face 20fe1 and both side end faces 20fe2 located on both sides of the central end face 20fe1. The central end face 20fe1 is recessed in the resonator length direction more than the both side end faces 20fe2. The edge 20ed of the main plane 20s1 in Modification 1 of Embodiment 1 is defined by the main plane 20s1 and the central end face 20fe1. The size of the recess in the Z direction of the central end face 20fe1 is, for example, 5 μm or more and 100 μm or less, the size in the X direction is, for example, 50 μm or more and 200 μm or less, and the size from the main plane 20s1 in the Y direction is, for example, 100 μm or more and 500 μm or less. The recess does not necessarily need to penetrate in the Y direction.

[0040] The emission surface 10e1 of the laser diode chip 10 protrudes in the resonator length direction beyond the edge 20ed of the main plane 20s1 defined by the main plane 20s1 and the central end face 20fe1. The both side end faces 20fe2 in the submount 20 protrude in the resonator length direction beyond the emission surface 10e1 of the laser diode chip 10, similarly to the end face 20se of the pair of lens support portions 20LS. By the edge 20ed of the main plane 20s1 defined by the main plane 20s1 and the central end face 20fe1, it is possible to suppress the bonding material from rising up to the emission surface 10e1 of the laser diode chip 10. The submount 20 in the first modification of the first embodiment can be easily manufactured because it suffices to remove only a part of the front end face 20fe in the above-described U-shaped configuration extending in the Z direction. Further, since the collimating lens 30 is bonded to an L-shaped end face including the end face 20se and the both side end faces 20fe2 of the pair of lens support portions 20LS, the contact area between the collimating lens 30 and the submount 20 becomes wide, and the bonding can be facilitated.

[0041] Next, with reference to FIGS. 4A to 4C, a configuration example of the laser light source 120 in Modification 2 of Embodiment 1 of the present disclosure will be described. FIG. 4A is a perspective view schematically showing a configuration example of the laser light source 120 in Modification 2 of Embodiment 1 of the present disclosure. FIG. 4B is a top view schematically showing the laser light source 120 of FIG. 4A. FIG. 4C is a cross-sectional view taken along line IVC-IVC parallel to the YZ plane of the configuration of FIG. 4B. The difference between the laser light source 120 in Modification 2 of Embodiment 1 and the laser light source 100 in Embodiment 1 is the shape of the submount 20. The submount 20 in Modification 2 of Embodiment 1 has grooves 20d extending along the resonator length direction between each of the pair of lens support portions 20LS and the laser diode chip 10. In the example shown in FIG. 4B, the groove 20d is adjacent to the pair of lens support portions 20LS, but it is not necessarily adjacent. The size of the groove 20d in the X direction is, for example, 100 μm or more and 500 μm or less, the size in the Y direction is, for example, 50 μm or more and 300 μm or less, and the size from the edge 20ed of the main plane 20s1 in the Z direction is, for example, 1 mm or more and 6 mm or less. The groove 20d does not necessarily need to penetrate in the Z direction. The groove 20d can reduce the influence of the heat applied to the bonding material when the end face 20se of the pair of lens support portions 20LS is bonded to the collimating lens 30 on the laser diode chip 10.

[0042] Next, with reference to FIGS. 5A to 5C, a configuration example of the laser light source 130 in Modification 3 of Embodiment 1 of the present disclosure will be described. FIG. 5A is a perspective view schematically showing a configuration example of the laser light source 130 in Modification 3 of Embodiment 1 of the present disclosure. FIG. 5B is a top view schematically showing the laser light source 130 of FIG. 5A. FIG. 5C is a cross-sectional view taken along the VC-VC line parallel to the YZ plane of the configuration of FIG. 5B. The difference between the laser light source 130 in Modification 3 of Embodiment 1 and the laser light source 100 in Embodiment 1 lies in the configuration of the submount 20. The submount 20 in Modification 3 of Embodiment 1 includes a first submount portion 20p1 and a second submount portion 20p2. The first submount portion 20p1 has a pair of lens support portions 20LS on the upper surface 20us. The first submount portion 20p1 has the above-described U-shaped shape extending in the Z direction. The first submount portion 20p1 can be formed of a ceramic including at least one selected from the group consisting of, for example, AlN, SiC, and alumina, and an alloy such as CuW. The second submount portion 20p2 is fixed to the upper surface 20us of the first submount portion 20p1 and is located between the pair of lens support portions 20LS. The second submount portion 20p2 has a main plane 20s1 on which the laser diode chip 10 is mounted and a front end face 20fe facing the collimating lens 30. The main plane 20s1 is a surface on the side of the second submount portion 20p2 opposite to the surface fixed to the upper surface 20us. In the present disclosure, the front end face 20fe and the back face 20s2 do not necessarily have to be directly connected. In the present disclosure, one side of the front end face 20fe and one side of the main plane 20s1 are in contact, and the side where the front end face 20fe and the main plane 20s1 are in contact defines the edge 20ed of the main plane 20s1. If the thermal conductivity of the second submount portion 20p2 is higher than the thermal conductivity of the first submount portion 20p1, the heat generated from the laser diode chip 10 can be efficiently transferred to the outside. The second submount portion 20p2 can be formed of at least one selected from the group consisting of, for example, Cu, Al, Ag, Fe, Ni, Mo, Cu, W, CuW, CuMo, AlN, SiC, and alumina.The size of the second submount portion 20p2 in the X direction is, for example, 0.5 mm or more and 1.5 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.

[0043] In this submount 20, the position of the second submount portion 20p2 can be adjusted on the first submount portion 20p1 by the separate first submount portion 20p1 and second submount portion 20p2. Like this submount 20, the portion having the main plane 20s1 and the portion having the pair of lens support portions 20LS may be separate. In this submount 20, a gap 20g exists between each of the pair of lens support portions 20LS and the second submount portion 20p2. The size of the gap 20g in the X direction is, for example, 50 μm or more and 300 μm or less. The sizes of the gap 20g in the Y and Z directions are determined by the sizes of the second submount portion 20p2 in the Y and Z directions, respectively. Similar to the laser light source 120 in the second modification of Embodiment 1, the gap 20g can reduce the influence of the heat applied to the bonding material on the laser diode chip 10 when the end face 20se of the pair of lens support portions 20LS is bonded to the collimating lens 30.

[0044] Next, with reference to FIGS. 6A to 6C, a configuration example of the laser light source 140 in Modification 4 of Embodiment 1 of the present disclosure will be described. FIG. 6A is a perspective view schematically showing a configuration example of the laser light source 140 in Modification 4 of Embodiment 1 of the present disclosure. In FIG. 6A, the laser diode chip 10, the submount 20, and the collimating lens 30 are shown in a separated state, but in reality, they are bonded together. FIG. 6B is a top view schematically showing the laser light source 140 of FIG. 6A. FIG. 6C is a cross-sectional view taken along the VIC-VIC line parallel to the YZ plane of the configuration of FIG. 6B. The difference between the laser light source 140 in Modification 4 of Embodiment 1 and the laser light source 100 in Embodiment 1 lies in the configuration of the submount 20. The submount 20 in Modification 4 of Embodiment 1 has a through hole 20h reaching from the main plane 20s1 to the back plane 20s2 and a metal 20m filling the through hole 20h. The portion of the submount 20 other than the through hole 20h can be formed of, for example, ceramic. The metal 20m has high thermal conductivity and can contain at least one selected from the group consisting of, for example, Cu, Al, Ag, Fe, Ni, Mo, Cu, W, and CuMo. The maximum size of the metal 20m in the X direction is, for example, 0.5 mm or more and 1.5 mm or less, and the maximum size in the Z direction is, for example, 1 mm or more and 6 mm or less. The metal 20m may entirely overlap the laser diode chip 10 or partially overlap it in a top view. By arranging the laser diode chip 10 in contact with the metal 20m in the submount 20, the heat generated from the laser diode chip 10 can be efficiently transmitted to the semiconductor laser package 40 through the metal 20m.

[0045] Next, with reference to FIGS. 7A to 7C, a configuration example of the laser light source 150 in Modification 5 of Embodiment 1 of the present disclosure will be described. FIG. 7A is a perspective view schematically showing a configuration example of the laser light source 150 in Modification 5 of Embodiment 1 of the present disclosure. FIG. 7B is a top view schematically showing the laser light source 150 of FIG. 7A. FIG. 7C is a cross-sectional view taken along line VIIc-VIIc parallel to the YZ plane of the configuration of FIG. 7B. The difference between the laser light source 150 in Modification 5 of Embodiment 1 and the laser light source 100 in Embodiment 1 is the shape of the collimating lens 30. The collimating lens 30 in Modification 5 of Embodiment 1 has a pair of flat portions 30f and a lens curved surface portion 30c sandwiched between the pair of flat portions 30f. The lens curved surface portion 30c in Modification 5 of Embodiment 1 functions as a FAC lens, similar to the collimating lens 30 in Embodiment 1.

[0046] Next, with reference to FIG. 7D, the advantages of the pair of flat portions 30f in the collimating lens 30 will be described. FIG. 7D is a perspective view schematically showing a state in which the collimating lens 30 in the laser light source 150 of FIG. 7A is joined to the submount 20 using a collet 60. The collet 60 has a bifurcated portion 60a and a support portion 60b connected to the bifurcated portion 60a. The collet 60 has a hollow structure and can adsorb and support the collimating lens 30. Specifically, the tip of the bifurcated portion 60a in the collet 60 adsorbs the pair of flat portions 30f in the collimating lens 30. By holding the support portion 60b with a mounting device and joining the collimating lens 30 to the submount 20 while supporting the collimating lens 30 with the bifurcated portion 60a, a load can be stably applied in a direction perpendicular to the end face 20se of the pair of lens support portions 20LS. In a state where a load is applied, the bonding material between the collimating lens 30 and the end face 20se of the pair of lens support portions 20LS is heated.

[0047] A mirror (not shown) may be provided between the bifurcated portions 60a in the collet 60. While emitting laser light from the laser diode chip 10 in the Z direction, the collimating lens 30 is joined to the submount 20, and the laser light reflected in the Y direction by the mirror (not shown) is received by a light receiving device, whereby the alignment between the collimating lens 30 and the emission surface 10e1 of the laser diode chip 10 can be performed more accurately. The light receiving device can be, for example, a power meter, a parallelism measuring device, or a beam profiler.

[0048] In a modification of the laser light source of the present disclosure, the submount 20 may further include a pair of heat insulating materials. Each of the pair of heat insulating materials may be provided in the middle of the path from the pair of lens support portions 20L in the submount 20 to the portion where the laser diode chip 10 is fixed. Hereinafter, typical modifications will be specifically described.

[0049] With reference to FIGS. 8A to 8C, a configuration example of the laser light source 160 in Modification 6 of Embodiment 1 of the present disclosure will be described. FIG. 8A is a perspective view schematically showing a configuration example of the laser light source 160 in Modification 6 of Embodiment 1 of the present disclosure. FIGS. 8B and 8C are a top view and a rear view schematically showing the laser light source 160 of FIG. 8A, respectively. The difference between the laser light source 160 in Modification 6 of Embodiment 1 and the laser light source 100 in Embodiment 1 is that the submount 20 includes a pair of heat insulating materials 20i extending in the resonator length direction on a flat plate portion other than the pair of lens support portions 20LS. The flat plate portion may have a depression as shown in FIG. 3A. Among the flat plate portions, the portion overlapping the main plane 20s1 in a top view is located between the pair of heat insulating materials 20i. The pair of heat insulating materials 20i are not in contact with the pair of lens support portions 20LS, respectively. The pair of heat insulating materials 20i can be formed of, for example, a glass fiber material or calcium silicate. The thickness of each heat insulating material 20i in the X direction is desirably 0.1 mm or more and 1 mm or less. By the pair of heat insulating materials 20i, it is possible to suppress the heat applied to the bonding material during the bonding of the end face 20se of the pair of lens support portions 20LS and the collimating lens 30 from being transmitted to the laser diode chip 10.

[0050] Next, with reference to FIGS. 9A to 9C, a configuration example of the laser light source 170 in Modification 7 of Embodiment 1 of the present disclosure will be described. FIG. 9A is a perspective view schematically showing a configuration example of the laser light source 170 in Modification 7 of Embodiment 1 of the present disclosure. FIGS. 9B and 9C are a side view and a rear view, respectively, schematically showing the laser light source 170 of FIG. 9A. The difference between the laser light source 170 in Modification 7 of Embodiment 1 and the laser light source 160 in Modification 6 of Embodiment 1 is that a pair of heat insulating materials 20i are respectively located directly below a pair of lens support portions 20L and are in contact with the pair of lens support portions 20LS. Even with this pair of heat insulating materials 20i arranged, it is possible to suppress the heat applied to the bonding material during the bonding of the end face 20se of the pair of lens support portions 20LS and the collimating lens 30 from being transmitted to the laser diode chip 10. In the laser light source 170 in Modification 7, compared with the laser light source 160 in Modification 6, the lateral width in the X direction of the main plane 20s1 located between the pair of heat insulating materials 20i is wider. Therefore, the heat generated from the laser diode chip 10 during the operation of the laser light source 170 can be more efficiently released to the outside through the portion overlapping the main plane 20s1 in a top view.

[0051] (Embodiment 2) Next, with reference to FIGS. 10A to 10D, a basic configuration example of the laser light source in Embodiment 2 of the present disclosure will be described.

[0052] FIG. 10A is a perspective view schematically showing a configuration example of the laser light source 200 in Embodiment 2 of the present disclosure. FIG. 10B is a top view schematically showing the laser light source 200 of FIG. 10A. FIG. 10C is a cross-sectional view taken along line VIIIC-VIIIC parallel to the YZ plane of the configuration of FIG. 10B. FIG. 10D is a rear view schematically showing the laser light source 200 of FIG. 10A. The difference between the laser light source 200 in Embodiment 2 and the laser light source 100 in Embodiment 1 lies in the configuration of the submount 20. The submount 20 in Embodiment 2 includes a third submount portion 20p3 and a fourth submount portion 20p4. The third submount portion 20p3 has a main plane 20s1, a back surface 20s2, and a front end face 20fe. The fourth submount portion 20p4 has a pair of lens support portions 20LS fixed to the main plane 20s1 of the third submount portion 20p3 and a connecting portion 20L connecting the pair of lens support portions 20LS. The connecting portion 20L connects the pair of lens support portions 20LS so as not to obstruct the propagation of the laser light emitted from the emission surface 10e1 of the laser diode chip 10. In this submount 20, the third submount portion 20p3 and the fourth submount portion 20p4 are separate bodies. A portion having the main plane 20s1 and a portion having the pair of lens support portions 20LS may be separate bodies like this submount 20. In FIG. 10A, the third submount portion 20p3, the fourth submount portion 20p4, and the collimating lens 30 are shown in a separated state, but actually they are joined. The pair of lens support portions 20LS and the connecting portion 20L in the fourth submount portion 20p4 are integrally formed.

[0053] As shown in FIGS. 10B and 10C, the connecting portion 20L overlaps with the emission surface 10e1 of the laser diode chip 10 in a top view. As shown in FIG. 10D, the fourth submount portion 20p4 is disposed on the main plane 20s1 of the third submount portion 20p3 so as to straddle the laser diode chip 10. Since the size of the fourth submount portion 20p4 in the X direction is larger than the size of the third submount portion 20p3 in the X direction, the area of the end face 20se of the pair of lens support portions 20LS can be widened. As a result, it becomes easy to bond the collimating lens 30 to the end face 20se of the pair of lens support portions 20LS. The size of the pair of lens support portions 20LS of the fourth submount portion 20p4 in the Y direction may be approximately the same as the size of the collimating lens 30 in the Y direction. The size of the pair of lens support portions 20LS of the fourth submount portion 20p4 in the Y direction may be larger than, equal to, or smaller than the size of the collimating lens 30 in the Y direction. The size of the fourth submount portion 20p4 in the X direction is, for example, 0.5 mm or more and 4 mm or less, the maximum size in the Y direction is, for example, 0.5 mm or more and 2 mm or less, and the size in the Z direction is, for example, 0.5 mm or more and 1 mm or less.

[0054] In the fabrication of the laser light source 200 in Embodiment 2, the steps of bonding the laser diode chip 10 to the main plane 20s1 of the third submount portion 20p3, bonding the fourth submount portion 20p4 to the main plane 20s1 of the third submount portion 20p3 so as to straddle the laser diode chip 10, and bonding the collimating lens 30 to the end face 20se of the pair of lens support portions 20LS in the fourth submount portion 20p4 may be executed in this order. Alternatively, the fourth submount portion 20p4 to which the collimating lens 30 is bonded may be bonded to the third submount portion 20p3 to which the laser diode chip 10 is bonded to the main plane 20s1.

[0055] In the laser light source 200 according to the second embodiment, similar to the laser light source 100 in the first embodiment, the submount 20 supports the laser diode chip 10 by the main plane 20s1 between the pair of lens support portions 20LS, and supports the collimating lens 30 by the end faces 20se of the pair of lens support portions 20LS. Thereby, alignment between the laser diode chip 10 and the collimating lens 30 becomes easy, and a small-sized laser light source 200 can be realized. Further, in the laser light source 200 according to the second embodiment, similar to the laser light source 100 in the first embodiment, even when the laser diode chip 10 is disposed in a face-down state on the submount 20, it is possible to suppress the bonding material from rising to the emission surface 10e1 of the laser diode chip 10.

[0056] (Modification Example of Embodiment 2) Next, modification examples 1 to 3 of the laser light source 200 in the second embodiment of the present disclosure will be described. Descriptions overlapping with the foregoing may be omitted.

[0057] Referring to FIGS. 11A to 11D, a configuration example of the laser light source 210 in Modification 1 of Embodiment 2 of the present disclosure will be described. FIG. 11A is a perspective view schematically showing a configuration example of the laser light source 210 in Modification 1 of Embodiment 2 of the present disclosure. FIG. 11B is a top view schematically showing the laser light source 210 of FIG. 11A. FIG. 11C is a cross-sectional view taken along the IXC-IXC line parallel to the YZ plane of the configuration of FIG. 11B. FIG. 11D is a rear view schematically showing the laser light source 210 of FIG. 11A. The difference between the laser light source 210 in Modification 1 of Embodiment 2 and the laser light source 200 in Embodiment 2 lies in the shape of the fourth submount portion 20p4 in the submount 20. The fourth submount portion 20p4 in Modification 1 of Embodiment 2 has a notch 20co between a pair of lens support portions 20LS in the fourth submount portion 20p4 in Embodiment 2. Due to the notch 20co, as shown in FIGS. 11B and 11C, the connecting portion 20L does not overlap the emission surface 10e1 of the laser diode chip 10 in a top view. The size of the notch 20co in the X direction is, for example, 0.2 mm or more and 3 mm or less, and the size in the Z direction is, for example, 0.5 mm or more and 1 mm or less. The size of the notch 20co in the Z direction is larger than the size in the Z direction between the end surface 20se of the pair of lens support portions 20LS and the edge 20ed of the main plane 20s1 in the third submount portion 20p3. In the fabrication of the laser light source 210 in Modification 1 of Embodiment 2, alignment between the emission surface 10e1 of the laser diode chip 10 and the fourth submount portion 20p4, and alignment between the emission surface 10e1 of the laser diode chip 10 and the collimating lens 30 are facilitated through the notch 20co.

[0058] Next, with reference to FIGS. 12A to 12D, a configuration example of the laser light source 220 in Modification 2 of Embodiment 2 of the present disclosure will be described. FIG. 12A is a perspective view schematically showing a configuration example of the laser light source 220 in Modification 2 of Embodiment 2 of the present disclosure. FIG. 12B is a top view schematically showing the laser light source 220 of FIG. 12A. FIG. 12C is a cross-sectional view taken along the XC-XC line parallel to the YZ plane of the configuration of FIG. 12B. FIG. 12D is a perspective view schematically showing the fourth submount portion 20p4 and the collimating lens 30 shown in FIG. 12A. The difference between the laser light source 220 in Modification 2 of Embodiment 2 and the laser light source 200 in Embodiment 2 lies in the fourth submount portion 20p4 in the submount 20 and the collimating lens 30. As shown in FIG. 12D, the fourth submount portion 20p4 and the collimating lens 30 in Modification 2 of Embodiment 2 are integrally formed. Since there is no need to join the fourth submount portion 20p4 and the collimating lens 30, the size of the fourth submount portion 20p4 in the X direction in Modification 2 of Embodiment 2 does not have to be as large as the size of the fourth submount portion 20p4 in the X direction in Embodiment 2. The size of the fourth submount portion 20p4 in the X direction in Modification 2 of Embodiment 2 is, for example, 0.2 mm or more and 3 mm or less, the maximum size in the Y direction is, for example, 0.3 mm or more and 1 mm or less, and the size in the Z direction is, for example, 0.5 mm or more and 1 mm or less.

[0059] The integrally formed fourth submount portion 20p4 and collimating lens 30 can be formed from at least one of, for example, glass, quartz, synthetic quartz, sapphire, transparent ceramic, and plastic. When the integrally formed fourth submount portion 20p4 and collimating lens 30 are transparent, it becomes easier to align the emission surface 10e1 of the laser diode chip 10 and the collimating lens 30.

[0060] Next, with reference to FIGS. 13A to 13C, a configuration example of the laser light source 230 in Modification 3 of Embodiment 2 of the present disclosure will be described. FIG. 13A is a perspective view schematically showing a configuration example of the laser light source 230 in Modification 3 of Embodiment 2 of the present disclosure. FIGS. 13B and 13C are a side view and a rear view, respectively, schematically showing the laser light source 230 of FIG. 13A. The difference between the laser light source 230 in Modification 3 of Embodiment 2 and the laser light source 200 in Embodiment 2 is that a pair of heat insulating materials 20i are arranged between the third submount portion 20p3 and the fourth submount portion 20p4. The pair of lens support portions 20LS in the fourth submount portion 20p4 are fixed to the main plane 20s1 of the third submount portion 20p3 via the pair of heat insulating materials 20i, respectively. The thickness of each heat insulating material 20i in the Y direction is desirably 0.1 mm or more and 1 mm or less. The pair of heat insulating materials 20i can suppress the heat applied to the bonding material during the bonding of the end face 20se of the pair of lens support portions 20LS and the collimating lens 30 from being transmitted to the laser diode chip 10.

[0061] The components in the above-described embodiments and their modifications may be arbitrarily combined.

[0062] (Method for manufacturing a laser light source) Hereinafter, with reference to FIGS. 14A to 15G, an example of the manufacturing process of the laser light source 100 in Embodiment 1 will be described. The manufacturing process may differ depending on the wavelength of the laser light emitted from the laser diode chip 10. The manufacturing process described below can be applied not only to the laser light source 100 in Embodiment 1 but also to all other laser light sources of the present disclosure.

[0063] FIGS. 14A to 14E are diagrams for explaining an example of the manufacturing process of the laser light source 100 when the submount 20 and the collimating lens 30 are bonded using an organic bonding material.

[0064] In the initial step, as shown in FIG. 14A, a submount 20 having a main plane 20s1 to which a laser diode chip 10 is fixed and a pair of lens support portions 20LS located on both sides of the emission surface 10e1 of the laser diode chip 10, and a collimating lens 30 are prepared.

[0065] In the next step, as shown in FIG. 14B, an end surface 20se of the pair of lens support portions 20LS and a bonding surface 30s of the collimating lens 30 are connected via an organic bonding material 72. The organic bonding material 72 is applied to at least one of the end surface 20se of the pair of lens support portions 20LS and the bonding surface 30s of the collimating lens 30 before connection. When using the organic bonding material 72, it is desirable that the emission wavelength of the laser diode chip 10 is a long wavelength such as red or infrared. This is because in the case of long-wavelength laser light, it is not necessary to consider the above-mentioned dust collection effect on the emission surface 10e1 of the laser diode chip 10. The organic bonding material 72 can be, for example, an ultraviolet-curable resin that cures by ultraviolet irradiation. For example, AT3862P of NTT Advanced Technology Corporation can be used for the organic bonding material 72. The curing shrinkage rate of AT3862P by ultraviolet irradiation is 0.5%. The thickness of the organic bonding material 72 can be, for example, 20 μm or more and 100 μm or less.

[0066] In the next step, as shown in FIGS. 14C and 14D, with the laser light being emitted from the laser diode chip 10, the position of the collimating lens 30 is adjusted so that the laser light is accurately collimated. FIGS. 14C and 14D are a top view and a side view schematically showing the laser light source 100 during manufacturing, respectively. The regions represented by the dashed lines shown in FIGS. 14C and 14D represent the state of the spread of the laser light. Since the organic bonding material before curing is easily deformed, such position adjustment is possible.

[0067] In the next step, as shown in FIG. 14E, the organic bonding material 72 is irradiated with ultraviolet light represented by the white arrow and cured, whereby the end face 20se of the pair of lens support portions 20LS and the bonding surface 30s of the collimating lens 30 are bonded with the organic bonding material 72. It is desirable that the curing shrinkage rate of the organic bonding material 72 due to ultraviolet irradiation is 2% or less. With the shrinkage rate within this range, it is possible to suppress the displacement of the adjusted position of the collimating lens 30.

[0068] By the above-described manufacturing process described with reference to FIGS. 14A to 14E, in the laser light source of the present disclosure, the laser light emitted from the laser diode chip 10 can be accurately collimated. This manufacturing process is advantageous in that the position of the collimating lens 30 can be adjusted before the organic bonding material is cured.

[0069] FIGS. 15A to 15G are diagrams for explaining an example of a manufacturing process of the laser light source 100 when the submount 20 and the collimating lens 30 are bonded using an inorganic bonding material. In this manufacturing process, instead of the organic bonding material 72, an inorganic bonding material 74 is used. Since no organic gas component is generated from the inorganic bonding material 74, or even if it is generated, it is extremely small, as described above, deterioration of the emission surface 10e1 of the short-wavelength laser diode chip 10 such as ultraviolet light, blue, or green during operation is suppressed. Since the inorganic bonding material 74 is not as deformable as the organic bonding material 72, the manufacturing process described below is different from the above-described manufacturing process described with reference to FIGS. 14A to 14E. Note that the order of the manufacturing process described below may be appropriately changed as long as there is no contradiction.

[0070] In the first step, as shown in FIG. 15A, a submount 20 having a main plane 20s1 to which the laser diode chip 10 is fixed and a pair of lens support portions 20LS located on both sides of the emission surface 10 e1 of the laser diode chip 10, and a collimating lens 30 are prepared.

[0071] In the next step, as shown in FIG. 15B, a first metal film 20mf1 is applied to the end face 20se of the pair of lens support portions 20LS. For example, the end face 20se of the pair of lens support portions 20LS can be subjected to Au plating. The first metal film 20mf1 can contain Au which is excellent in oxidation resistance. The first metal film 20mf1 can also be provided on the front end face 20fe shown in FIGS. 2A, 3A, 4A, 6A, and 7A. Further, the first metal film 20mf1 can be provided on portions other than the end face 20se of the pair of lens support portions 20LS among the U-shaped surfaces shown in FIGS. 5A and 10A.

[0072] In the next step, as shown in FIG. 15B, using an autocollimator 80, the end face 20se of the pair of lens support portions 20LS is adjusted to be parallel to a reference plane parallel to the XY plane. Specifically, using the autocollimator 80, the inclination of the end face 20se of the pair of lens support portions 20LS with respect to the reference plane is reduced. The autocollimator 80 is an optical device that measures the inclination of a part surface non - contact. Among autocollimators 80, a laser autocollimator can emit a laser beam and accurately measure a minute inclination of a part surface based on the laser beam reflected by the surface of an optical component. For example, the laser autocollimator of Suruga Seiki Co., Ltd. has an angular resolution of 0.0008 degrees. The white arrows shown in FIG. 15B represent the laser beam emitted from the autocollimator 80 and reflected by the first metal film 20mf1. The first metal film 20mf1 efficiently reflects the laser beam emitted from the autocollimator 80.

[0073] In the next step, as shown in FIG. 15C, a second metal film 20mf2 is applied to the bonding surface 30s of the collimating lens 30. The second metal film 20mf2 can use the same material as the aforementioned first metal film 20mf1.

[0074] In the next step, as shown in FIG. 15C, using the autocollimator 80, the joint surface 30s of the collimating lens 30 is adjusted to be parallel to the above reference plane. Specifically, using the autocollimator 80, the inclination of the joint surface 30s of the collimating lens 30 with respect to the reference plane is reduced. The autocollimator 80 for adjusting the joint surface 30s of the collimating lens 30 may be the same as or different from the autocollimator 80 for adjusting the end face 20se of the pair of lens support portions 20LS. When the same laser autocollimator 80 is used, the laser light emitted from the laser autocollimator 80 can be separated into two laser lights by an optical system such as a beam splitter. Of the two separated lights, one is reflected by the first metal film 20mf1 and the other is reflected by the second metal film 20mf2.

[0075] In the next step, as shown in FIG. 15D, with the end face 20se of the pair of lens support portions 20LS and the joint surface 30s of the collimating lens 30 maintained parallel to the reference plane, the end face of the pair of lens support portions 20LS and the joint surface 30s of the collimating lens 30 are connected via the inorganic bonding material 74. The inorganic bonding material 74 is applied to at least one of the end face 20se of the pair of lens support portions 20LS and the joint surface 30s of the collimating lens 30 before connection.

[0076] The inorganic bonding material 74 may contain, for example, AuSn. The thickness of the inorganic bonding material 74 is 5 μm or less, and desirably may be 2.5 μm or less. The inorganic bonding material 74 can be formed, for example, from a metal film of AuSn or an AuSn paste. The metal film of AuSn can be provided by sputtering. The organic binder in the AuSn paste can be vaporized by heating the inorganic bonding material 74 by laser irradiation described later. If the volume ratio of the organic binder in the AuSn paste is, for example, 10% or more and 20% or less, the shrinkage of the inorganic bonding material 74 when all the organic binder is vaporized can be suppressed within 0.5 μm. Therefore, even when the inorganic bonding material 74 is heated by laser irradiation, the inclination between the end face 20se of the pair of lens support portions 20LS and the bonding surface 30s of the collimating lens 30 does not excessively increase. The inorganic bonding material 74 may be formed from a solder material such as an Au-Sn eutectic solder or a Sn-Ag-Cu solder, or a nanoparticle material such as Ag nanoparticles, Cu nanoparticles, or Au nanoparticles, in addition to the metal film of AuSn or the AuSn paste.

[0077] In the next step, the submount 20 is heated to 150°C or higher and 200°C or lower. By this heating, it is possible to suppress the heat applied to the inorganic bonding material 74 by laser irradiation from being released to the outside through the submount 20. The submount 20 can be heated by a heater. Alternatively, as shown in FIGS. 15E and 15F, the submount 20 can be heated by the heat generated when the laser diode chip 10 emits laser light. FIGS. 15E and 15F are a top view and a side view schematically showing the laser light source 100 during manufacturing, respectively. The regions represented by the dashed lines shown in FIGS. 15E and 15F represent the spread of the laser light. In this step, it is not necessary to accurately collimate the laser light. Usually, when the laser light source 100 operates, the submount 20 is placed on a heat sink so that the heat generated from the laser diode chip 10 is released to the outside. In contrast, in this step of heating the submount 20, a current is injected into the laser diode chip 10 without placing the submount 20 on a heat sink. In this case, when a current of about 1 A to 2 A is injected to emit laser light from the laser diode chip 10, the temperature of the submount 20 exceeds 200°C. When the submount 20 is placed on a heat sink, the injection current when the temperature of the submount 20 exceeds 200°C is about 7 A to 8 A.

[0078] In the next step, as shown in FIG. 15G, the inorganic bonding material 74 is irradiated and heated with laser light represented by the white arrow, whereby the end face 20se of the pair of lens support portions 20LS and the bonding surface 30s of the collimating lens 30 are bonded with the inorganic bonding material 74. Due to the presence of the first metal film 20mf1 and the second metal film 20mf2, the end face 20se of the pair of lens support portions 20LS and the bonding surface 30s of the collimating lens 30 can be effectively bonded with the inorganic bonding material 74. At the time of bonding, the collimating lens 30 is loaded in a direction perpendicular to the end face 20se of the pair of lens support portions 20LS as represented by the thick black arrow. The collimating lens 30 shifts by 2 μm or more and 3 μm or less in the direction of the load. By this shift, with the laser light being emitted from the laser diode chip 10, the position of the collimating lens 30 can be finely adjusted to accurately collimate the laser light.

[0079] As shown in FIG. 15G, the inorganic bonding material 74 is irradiated with laser light in an oblique direction with respect to the end face 20se of the pair of lens support portions 20LS through the side surface of the collimating lens 30. By the laser irradiation in the oblique direction, the inorganic bonding material 74 can be efficiently heated. When a YAG laser light source is used, the laser light has a near-infrared wavelength. When a laser light source other than the YAG laser light source is used, the laser light may have a wavelength of visible light such as blue or green, or a wavelength of ultraviolet light. As shown in FIGS. 8A and 9A, if the submount 20 includes a pair of heat insulating materials 20i, it is possible to suppress the heat applied to the inorganic bonding material 74 from being transmitted to the laser diode chip 10.

[0080] By the above-described manufacturing process described with reference to FIGS. 15A to 15G, in the laser light source of the present disclosure, the laser light emitted from the laser diode chip 10 can be accurately collimated.

[0081] (Application Example) The laser light source of the present disclosure can be used, for example, as a light source of a direct diode laser that combines a plurality of laser beams to increase the output. Beam combination is performed by accurately combining the laser beams emitted from a plurality of laser light sources. According to a high-intensity laser beam having a wavelength of 570 nm or less, it becomes easy to process a metal such as copper, for example. In the laser light source of the present disclosure, displacement between the laser diode chip and the lens is less likely to occur, so the direction of the optical axis of the laser light emitted from the laser light source to the outside does not deviate significantly. It becomes possible to accurately combine the laser beams emitted from a plurality of laser light sources and improve the beam quality.

[0082] The laser light source of the present disclosure can also be used, for example, in a projector and a lighting fixture.

Description of Signs

[0083] 10 Laser diode chip 10a Semiconductor laminate 10b Submount 10C1 First cladding layer 10C2 Second cladding layer 10e1 Emission surface 10e2 Rear surface 10L Light-emitting layer 20 Submount 20co Notch 20d Groove 20ed Edge 20fe Front end face 20fe1 Central end face 20fe2 Both side end faces 20h Through hole 20i Heat insulating material 20L Connecting portion 20LS Lens support portion 20mf1 First metal film 20mf2 Second metal film 20p1 First submount portion 20p2 Second submount portion 20p3 Third submount portion 20p4 Fourth submount portion 20s1 main plane 20s2 back surface 20se end faces of a pair of lens support portions 20us upper surface of the first submount portion 30 collimating lens 30c lens curved surface portion 30f flat portion 30s joint surface of the collimating lens 40 semiconductor laser package 40b base 40L lid 40w light-transmitting window 50 lead terminal 60 collet 60a bifurcated portion 60b support portion 72 organic bonding material 74 inorganic bonding material 80 autocollimator 100, 110, 120, 130, 140, 150, 160, 170 laser light sources 200, 210, 220, 230 laser light sources

Claims

1. Preparing a submount having a main plane to which a laser diode chip having an emission surface is fixed, and a pair of lens support portions located on both sides of the emission surface of the laser diode chip; Preparing a lens; Adjusting so that an end surface of the pair of lens support portions in the submount and a bonding surface of the lens are parallel; Connecting the end surface and the bonding surface via an inorganic bonding material; Heating the submount; Heating the inorganic bonding material by laser irradiation; Including; The method for manufacturing a laser light source, wherein the connecting step includes a step of applying a load to the lens in a direction perpendicular to the end surface.

2. The method for manufacturing a laser light source according to claim 1, wherein the step of heating the submount includes a step of heating the submount with a heater.

3. The method for manufacturing a laser light source according to claim 1, wherein the step of heating the submount includes a step of heating the submount with heat generated by the laser diode chip emitting laser light.

4. The method for manufacturing a laser light source according to any one of claims 1 to 3, wherein when heating the inorganic bonding material by laser irradiation, the temperature of the heated submount is 200°C or less.

5. The method for manufacturing a laser light source according to any one of claims 1 to 4, wherein the step of heating the inorganic bonding material by laser irradiation includes a step of irradiating the inorganic bonding material with laser light through the lens.

6. Providing a first metal film on the end surface of the pair of lens support portions; Providing a second metal film on the bonding surface of the lens; The method for manufacturing a laser light source according to any one of claims 1 to 5, further including.

7. The first metal film and the second metal film contain Au, The method for manufacturing a laser light source according to claim 6, wherein the inorganic bonding material contains AuSn.

8. The submount further includes a pair of heat insulating materials, The method for manufacturing a laser light source according to any one of claims 1 to 7, wherein each of the pair of heat insulating materials is provided in the middle of a path from the pair of lens support portions in the submount to the portion where the laser diode chip is fixed.

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