Laser stacking

Abstract

The embodiment of the present invention provides a laser stack, including a laser unit and a fixed base, wherein the laser unit includes a laser chip and a conductive substrate, wherein the conductive substrate includes a first end and a second end, wherein the laser chip is bonded to the side surface of the first end of the conductive substrate, and the second end of the conductive substrate has a three-dimensional structure inclined relative to the first end, and both side surfaces of the inclined three-dimensional structure have roughness, and a buffer layer is provided on at least one side of the two side surfaces of the inclined three-dimensional structure, and the buffer layer contacts the corresponding surface to generate a friction force for fixing, and the laser unit is bonded to the fixed base. Based on the laser stack provided by the present invention, the disassembly and reassembly of the stack can be effectively realized, and the technical problem that the vertical force cannot be guaranteed in the prior art is solved, the structure is simple, the firmness and reliability are higher, and it has a large application range.

Description

Technical Field

[0001] The invention relates to the field of semiconductor lasers, and in particular to a laser stack array. Background Art

[0002] In the field of semiconductor laser packaging technology, the traditional conduction-cooled semiconductor laser stack includes two types. One type is formed by welding, such as Figure 1 , a stacked array formed by mechanical clamping, such as Figure 2 .

[0003] Figure 1 In the process, once the stacked array is bonded, it is difficult to disassemble, reassemble or repair it, and re-bonding is often accompanied by contamination or damage of the laser chip. Figure 2 In the mechanical clamping scheme, there is only horizontal force applied, but no vertical force. Therefore, the problem is that there is no force constraint in the vertical direction. When facing longitudinal vibration, the stacked array is prone to fall off, making the semiconductor laser stacked array not firmly fixed, seriously affecting its reliability. Summary of the invention

[0004] In view of this, the present invention provides a laser stack array, which can effectively solve the technical problems in the prior art that it is difficult to disassemble, reassemble or repair, and cannot ensure the application of force in the vertical direction by designing a new packaging unit structure. It has a simple structure, higher firmness and reliability, and a large range of applications.

[0005] The technical solution of the present invention is achieved in this way:

[0006] The present invention provides a laser stack array, comprising a laser unit and a fixed base, wherein the laser unit comprises a laser chip and a conductive substrate, wherein the conductive substrate comprises a first end and a second end, wherein the laser chip is bonded to the side surface of the first end of the conductive substrate, and the second end of the conductive substrate has a three-dimensional structure inclined relative to the first end, and both side surfaces of the inclined three-dimensional structure have roughness, and a buffer layer is arranged on at least one side of the two side surfaces of the inclined three-dimensional structure, and the buffer layer contacts with the corresponding surface to generate friction force for fixation, and the laser unit is bonded to the fixed base.

[0007] In the above scheme, the second end of the conductive substrate has a three-dimensional structure inclined relative to the first end, including: the second end of the conductive substrate has a fixed substrate inclined relative to the first end, and the conductive substrate and the inclined fixed substrate are in a fold line shape.

[0008] In the above scheme, the second end of the conductive substrate has a three-dimensional structure inclined relative to the first end, including: the second end of the conductive substrate has an extension portion, the extension portion is inclined relative to the first end, and the extension portions of the first and second ends of the conductive substrate are in a fold line shape.

[0009] In the above solution, the second end of the conductive substrate has a three-dimensional structure inclined relative to the first end, including: the end surface of the second end of the conductive substrate is an inclined surface.

[0010] In the above solution, a fixed substrate having a matching inclination is provided at the inclined surface.

[0011] In the above solution, the width of the inclined three-dimensional structure at the second end of the conductive substrate is less than or equal to the width of the first end of the conductive substrate.

[0012] In the above solution, a buffer layer is provided on at least one of the two side surfaces of the inclined three-dimensional structure, and the buffer layer is in contact with the corresponding surface to generate a friction force for fixing.

[0013] The above solution comprises a plurality of the laser units, and the plurality of the laser units are bonded to the fixed base.

[0014] In the above solution, the fixed base and the plurality of laser units are mechanically fixedly connected, and the two are perpendicular or inclined to each other.

[0015] Beneficial technical effects of the present invention:

[0016] 1. Due to the design of a new type of laser unit, each laser unit is relatively independently bonded to the fixed base. When a laser unit fails, the corresponding laser unit can be directly disassembled and replaced, which is more convenient.

[0017] 2. The arrangement of the inclined three-dimensional structure in the laser unit makes the external force applied to the inclined three-dimensional structure perpendicular to the inclined surface of the inclined three-dimensional structure downward, and the force is decomposed to generate a force in the vertical direction.

[0018] 3. When multiple laser units form a stacked array, combined with pressure and friction in other directions, the multiple units are fixed on the fixed base as a whole, which makes them more secure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a packaging structure 1 in the prior art;

[0020] Figure 2 This is the second packaging structure in the prior art;

[0021] Figure 3 The structure of the laser unit of the present invention is shown in FIG. Figure 1

[0022] Figure 4 The structure of the laser stack array of the present invention is shown in FIG. Figure 1 ;

[0023] Figure 5The structure of the laser unit of the present invention is shown in FIG. Figure 2 ;

[0024] Figure 6 The structure of the laser stack array of the present invention is shown in FIG. Figure 2 ;

[0025] Figure 7 The structure of the laser stack array of the present invention is shown in FIG. Figure 3 ;

[0026] Figure 8 The structure of the laser stack array of the present invention is shown in FIG. Figure 4 ;

[0027] Fig. 9 The structure of the laser stack array of the present invention is shown in FIG. Figure 5 ;

[0028] Fig.10 The structure of the laser stack array of the present invention is shown in FIG. Figure 6 ;

[0029] Fig.11 It is the force diagram of the inclined three-dimensional structure of the present invention;

[0030] Figure 12-16 It is a schematic diagram of the structure of the mechanically fixed laser stack array of the present invention.

[0031] Explanation of the accompanying drawings: 1 is a laser stack, 11 is a laser chip, 12 is a conductive substrate, A is a first end of the conductive substrate, a is an end surface of the first end of the conductive substrate, B is a second end of the conductive substrate, C is an extension of the second end, b is an end surface of the second end of the conductive substrate, 13 is a fixed substrate, 14 is a buffer layer, 15 is a thermally conductive film, 16 is a heat sink, 17 is a lead-out electrode, 18 is a spring, D is a width of the conductive substrate, d is a width of the inclined three-dimensional structure at the second end of the conductive substrate, α is an oblique angle of the inclined three-dimensional structure, S1 is a left surface of the inclined three-dimensional structure, and S2 is a right surface of the inclined three-dimensional structure. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0033] The embodiment of the present invention provides a laser unit and a laser stack array, such as Figure 3 As shown, the laser unit includes: a laser chip 11, a conductive substrate 12, and the conductive substrate 12 includes a first end A and a second end B, wherein the side of the first end A of the conductive substrate 12 is bonded to the laser chip 11, and the second end B of the conductive substrate 12 has a three-dimensional structure inclined relative to the first end A.

[0034] Generally speaking, for the inclined three-dimensional structure, the larger the bevel angle, the stronger it is. However, when the bevel angle is large, the corresponding heat conduction path will also become longer. Therefore, in practice, both strength and heat conduction need to be taken into account. The bevel angle of the inclined three-dimensional structure should satisfy the premise of balanced heat conduction and not interfere with adjacent inclined three-dimensional structures. In other words, the bevel angle cannot be increased infinitely to improve the strength, because the elongation of the heat conduction path will reduce the heat conduction efficiency, and the larger the bevel angle, the higher the possibility of interference with adjacent inclined three-dimensional structures.

[0035] The first end of the conductive substrate of the present invention is a straight strip-shaped sheet structure, and the second end is collinear and parallel to the first end. The second end has an inclined three-dimensional structure that forms a certain angle with the first end, that is, it is relatively inclined. It should be noted that "straight", "vertical" and "inclined" are relative concepts indicating position or structure, and the "inclined" in the inclined three-dimensional structure refers to the straight first end of the conductive substrate.

[0036] There are many situations in which the second end of the conductive substrate has an inclined three-dimensional structure. For example, an extension portion as an inclined three-dimensional structure can be set at the end of the second end, or other independent inclined three-dimensional structures can be set at the second end. Various situations are further explained in combination with the drawings and specific embodiments below.

[0037] Embodiment 1

[0038] By arranging an inclined fixed substrate at the second end of the conductive substrate, the second end of the conductive substrate can have a three-dimensional structure inclined relative to the first end. The fixed substrate can be an insulating substrate or a conductive substrate.

[0039] Figure 3 The structure of the laser unit of the present invention is shown in FIG. Figure 1 ,like Figure 3 The second end B of the conductive substrate 12 shown has an inclined three-dimensional structure, specifically including: the second end B of the conductive substrate 12 has a fixed substrate 13 inclined relative to the first end A, the conductive substrate 12 and the inclined fixed substrate 13 are in a broken line shape as a whole, and the two end faces of the fixed substrate 13 can be planes or inclined surfaces, as long as they cooperate with adjacent structures during packaging.

[0040] In the embodiment of the present invention, the width of the inclined three-dimensional structure at the second end B of the conductive substrate 12 is less than or equal to the width of the first end of the conductive substrate 12, and all the following embodiments are applicable. Figure 5 Figure 6 It is understood (similar to other figures), the horizontal direction is defined as the stacking direction when multiple laser units form a stacked array, the width of the inclined three-dimensional structure is the thickness of the second end B of the conductive substrate 12 in the horizontal direction, and the width of the first end of the conductive substrate 12 is the thickness of the first end A of the conductive substrate 12 in the horizontal direction.

[0041] like Figure 5 Figure 6 As shown, based on the first embodiment, the width of the fixed substrate 13 is d, the width of the conductive substrate 12 is D, and the width d of the fixed substrate 13 is less than or equal to the width D of the conductive substrate 12 .

[0042] Figure 4 The case where the width d of the fixed substrate 13 is equal to the width D of the conductive substrate 12, Figure 5 Figure 6 This is the case where the width d of the fixed substrate 13 is smaller than the width D of the conductive substrate 12 .

[0043] Reference Figure 5 Figure 6 When the width d of the fixed substrate 13 is smaller than the width D of the conductive substrate 12, the conductive substrate 12 will press a portion of the buffer layer 14. The advantage of this structure is that the buffer layer 14 will be constrained between the fixed substrate 13 and the heat sink 16 due to the existence of friction. Under this structure, the conductive substrate 12 will also block the buffer layer 14 from above, so that the buffer layer 14 will not pop out during the vibration process, thereby further improving the firmness and reliability of the entire laser stack.

[0044] Embodiment 2

[0045] Different from the above first embodiment, in this embodiment, an extension portion C is provided at the end of the second end B of the conductive substrate 12, so that the second end of the conductive substrate has a three-dimensional structure inclined relative to the first end.

[0046] like Figure 7 As shown, the second end B of the conductive substrate has an inclined three-dimensional structure relative to the first end, including: the second end B of the conductive substrate 12 has an extension portion C, the extension portion is inclined relative to the first end, the extension portions of the first end A and the second end B of the conductive substrate 12 are in a broken line shape as a whole, and the extension portion and the conductive substrate 12 can be an integrated structure, that is, the conductive substrate 12 is designed to be in a broken line shape as a whole, so that when forming a laser stack array, multiple laser units can be directly bonded to the heat sink 16, and the structure is simpler and more compact.

[0047] In this embodiment, the end surface of the extension portion C of the second end of the conductive substrate can be a plane or an inclined surface, as long as it cooperates with the adjacent structure during packaging. The extension portion C of the second end of the conductive substrate 12 forms a certain angle with the first end.

[0048] Embodiment 3

[0049] By setting the end surface of the second end of the conductive substrate as an inclined plane, the second end of the conductive substrate has an inclined three-dimensional structure. The inclined plane is relative to the horizontal reference plane, and the plane forming a certain angle with the horizontal reference plane is the inclined plane.

[0050] like Figure 8 As shown, the second end of the conductive substrate has an inclined three-dimensional structure, including: the end surface b of the second end of the conductive substrate 12 is an inclined surface. In this case, when forming a laser stack, the lengths of the various conductive substrates can be different, and can be increased or decreased in a certain regular pattern.

[0051] In this embodiment, the inclined three-dimensional structure (inclined surface) has a certain angle with the first end, that is, it is inclined relative to the first end.

[0052] Embodiment 4

[0053] Based on the above embodiment 3, Fig. 9 As shown, when the end face b of the second end of the conductive substrate 12 is an inclined surface, a fixed substrate matching the inclination of the inclined surface may be further provided at the inclined surface, and the fixed substrate 13 is bonded to the conductive substrate 12 .

[0054] In this case, when forming a laser stack array, the lengths of each conductive substrate can be different, increasing or decreasing in a certain pattern, and the length of the fixed substrate 13 is the same; or, the lengths of each conductive substrate can be the same, and the lengths of the fixed substrate 13 are different, increasing or decreasing in a certain pattern, or other forms are possible as long as they can be matched with the heat sink for bonding.

[0055] Based on the above embodiments, the present invention further provides a laser stack array, which includes a plurality of the above-mentioned laser units and a fixed base, wherein the plurality of laser units are bonded to the fixed base.

[0056] In the embodiment of the present invention, the fixed base is a heat sink 16, and the plurality of laser units are bonded to the heat sink 16. The heat sink 16 is also used to dissipate heat for the plurality of laser units. As described above, the lengths of the conductive substrates in the plurality of laser units may be equal or different, for example, Figure 8 Fig. 9 The figure shows the case where the lengths of the conductive substrates are unequal, and the other figures show the case where the lengths of the conductive substrates are equal. The length of the conductive substrate is the distance from the end face a of the first end A to the end face b of the second end B of the conductive substrate.

[0057] As shown in the accompanying drawings, in the area where the heat sink 16 is located, a buffer layer 14 is also arranged between the inclined three-dimensional structures of multiple laser units to tolerate deformation generated during the bonding process and release the stress of the laser chip. The buffer layer 14 is the same as the buffer layer in the aforementioned "a buffer layer is arranged on at least one of the two side surfaces of the inclined three-dimensional structure" and can be regarded as the same buffer layer to a certain extent. Friction is formed between the buffer layer 14 and the contact surface of the inclined three-dimensional structure to achieve fixation.

[0058] The thickness and shape of the buffer layer 14 at both ends of the laser stack are determined by the spacing and gap between the multiple laser units and the heat sink, and the thickness and shape of the buffer layer 14 between adjacent laser units are determined by the spacing and gap between adjacent inclined three-dimensional structures.

[0059] A heat-conducting film 15 is further provided on the bonding interface between the plurality of laser units and the heat sink, so as to promote heat conduction between the plurality of laser units and the heat sink and improve heat dissipation.

[0060] The heat sink and the plurality of laser units are usually mechanically fixedly connected, and the mechanically fixed connection methods may specifically include but are not limited to: threaded connection, interference fit, spring clip fastening, thermal expansion and contraction, and no pressure block.

[0061] Specifically, the threaded connection can be fixed by setting screw holes and external bolts at the pressing blocks on both sides of the heat sink, see Fig.12 , the dotted line area is the screw hole and bolt; the interference fit is achieved by the heat sink itself, the pressing blocks on both sides of the heat sink are provided with protrusions, and slots are opened at the corresponding positions on the heat sink body according to the error requirements of the interference fit, and the protrusions are inserted into the slots in an interference manner, see Fig.13 The spring fastening type is a plurality of elastic springs 18 arranged in the gap between the heat sink and the plurality of laser units, see Fig.14 ; The heat sink is heated during assembly. The heat sink is made of metal with a large thermal expansion coefficient. When heated, the size of the heat sink increases. At this time, multiple laser units are placed in the heat sink (in the U-shaped mouth in the figure). After cooling, they shrink to achieve fixation. See Fig.15 The non-pressure block type has no pressure blocks on both sides of the heat sink to tighten downward, but because the buffer layer 14 has a certain friction force, during the assembly process, by applying a certain pre-tightening force to the buffer layer 14 on both sides, it can still be fixed in both the horizontal and vertical directions, see Fig.16 .

[0062] When the heat sink 16 and the plurality of laser units are mechanically fixedly connected, the heat sink 16 and the plurality of laser units may be perpendicular to each other. Figures 4 to 7 , Fig.10When fixed, the pressure direction of the heat sink 16 is parallel to the stacking direction of the multiple laser units; or, the heat sink 16 and the multiple laser units can be arranged to be inclined to each other (that is, non-vertical), see Figure 8 Fig. 9 At this time, among the multiple laser units, the pressure direction of the heat sink 16 forms a certain angle with the stacking direction of the multiple laser units when they are fixed.

[0063] In the embodiment of the present invention, the end surface a of the first end A of each conductive substrate can be a plane or an inclined surface, and the end surface b of the second end B can be adaptively set directly as an inclined surface or a plane in the above solution.

[0064] Furthermore, the buffer layer 14 may include but is not limited to: FPC, or plastic, or rubber, etc. Each buffer layer 14 contacts the inclined three-dimensional structure of the adjacent laser unit to achieve fixation to a certain extent; the inclined three-dimensional structure may be an oblique cube with a parallelogram cross section, such as Figures 3 to 6 , or it can be an oblique cube with a trapezoidal cross section, such as Fig.10 .

[0065] Fig.11 It is the force diagram of the inclined three-dimensional structure of the present invention, such as Fig.11 Taking multiple laser units packaged and fixed on a heat sink as an example, the force perpendicular to the left and right inclined surfaces of the inclined three-dimensional structure is the positive pressure applied to these two planes when fixed, the upward force on the bottom surface of the vertical three-dimensional structure is the positive pressure applied to the inclined three-dimensional structure by the bottom surface, and the force parallel to the left and right inclined surfaces of the three-dimensional structure is the two friction forces applied to the inclined three-dimensional structure by the buffer layer 14 on both sides. The above forces can at least achieve sufficient fixation of the inclined three-dimensional structure and each laser unit.

[0066] In all the above embodiments of the present invention, the two side surfaces (S1, S2) of the inclined three-dimensional structure are inclined planes. Assuming that the horizontal direction is used as the direction of force application, the two side surfaces of the inclined three-dimensional structure are force-bearing surfaces for applying force in the horizontal direction. The force applied to the inclined three-dimensional structure acts perpendicularly to the inclined plane. This force perpendicular to the inclined plane will be decomposed into horizontal and vertical component forces, thereby generating a force in the vertical direction. When the direction of force application is not along the horizontal direction, the idea is basically similar to the above.

[0067] Furthermore, both side surfaces of the inclined three-dimensional structure may have roughness, and the roughness can generate friction with other contacting structures or surfaces.

[0068] Specifically, for a single laser unit, in situations where high stability is required or the application is demanding, a buffer layer can be provided on at least one of the two side surfaces of the inclined three-dimensional structure. The buffer layer contacts the corresponding surface to generate a friction force for fixation. The direction of the friction force is parallel to the inclined surface. The friction force can also be decomposed into horizontal and vertical components, thereby promoting further fixation of the laser unit and the stacked array to meet high-standard fixation requirements and application scenarios. In this case, multiple laser units can directly form a stacked array.

[0069] In the case of low stability or less demanding applications, the corresponding technical effect can be achieved by directly applying force to the force-bearing surface alone, that is, no buffer layer is provided. In this case, multiple laser units need to be stacked when forming an array. Figure 12-Figure 15 The fixed base of the middle U-shaped structure, although there is no buffer layer to transmit the external force for fixing in the direction of the inclined three-dimensional structure, the two ends of the opening of the U-shaped fixed base can be used to contact the surfaces of the conductive substrates at both ends, and the two ends of the opening of the U-shaped fixed base can apply external force to the surfaces of the two conductive substrates in contact to achieve fixation.

[0070] It should be noted that the inclined three-dimensional structure of the laser unit serves as a force-bearing body subjected to external force, and the vertical force ultimately acting on it is related to the roughness of its two side surfaces, the roughness of the buffer layer surface, the external force acting on its two side surfaces, the oblique angle of the inclined three-dimensional structure, etc., and it is also necessary to consider factors such as the influence of external forces in the application scenarios of the laser unit and the stacked array. This part requires comprehensive consideration of various conditions for accurate and detailed calculations. It is not the key technical point elaborated in the present invention, and the present invention will not elaborate on this.

[0071] The subject that applies external force from the outside world may be a fixed base or a heat sink as described below, or other forms. In principle, as long as it can apply external force to the laser unit, there is no special restriction here.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A laser stacking array, It is characterized in that It comprises a laser unit and a fixed base, wherein the laser unit comprises a laser chip and a conductive substrate, wherein the conductive substrate comprises a first end and a second end, wherein: The laser chip is bonded to the side surface of the first end of the conductive substrate, and the second end of the conductive substrate has a three-dimensional structure inclined relative to the first end. The two side surfaces of the inclined three-dimensional structure have roughness. A buffer layer is provided on at least one side of the two side surfaces of the inclined three-dimensional structure. The buffer layer contacts the corresponding surface to generate friction force for fixing, and the laser unit is bonded to the fixed base.

2. The laser stack according to claim 1, It is characterized in that The second end of the conductive substrate has a three-dimensional structure inclined relative to the first end, including: The second end of the conductive substrate has a fixed substrate which is tilted relative to the first end, and the conductive substrate and the tilted fixed substrate are in a zigzag shape.

3. The laser stack according to claim 1, It is characterized in that The second end of the conductive substrate has a three-dimensional structure inclined relative to the first end, including: The second end of the conductive substrate has an extension portion, and the extension portion is arranged obliquely relative to the first end. The extension portions of the first end and the second end of the conductive substrate are in a fold line shape.

4. The laser stack according to claim 1, It is characterized in that The second end of the conductive substrate has a three-dimensional structure inclined relative to the first end, including: an end surface of the second end of the conductive substrate is an inclined surface.

5. The laser stack according to claim 4, It is characterized in that A fixed substrate having a matching inclination is provided at the inclined surface.

6. The laser stack array according to any one of claims 1 to 5, It is characterized in that The width of the inclined three-dimensional structure at the second end of the conductive substrate is less than or equal to the width of the first end of the conductive substrate.

7. The laser stack according to claim 1, It is characterized in that It comprises a plurality of the laser units, and the plurality of the laser units are bonded to the fixed base.

8. The laser stack according to claim 7, It is characterized in that The fixed base and the plurality of laser units are mechanically fixedly connected, and the two are perpendicular or inclined to each other.

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