VCSEL chip module, microlens and manufacturing method thereof

Abstract

The present invention provides a VCSEL chip module and its microlens and manufacturing method, which relate to the technical field of VCSEL chips, and include a microlens body, wherein the microlens body has at least one optical surface, and the optical surface working distance of the microlens body is t≥5a, where a is the diameter of the light source emission hole; the microlens body and the light source emission hole correspond one to one. Optical elements for shaping the light beam emitted by a VCSEL bare chip have the technical problem of occupying a large space, and the optimized shaping of the VCSEL output beam quality parameters is achieved on a chip-level scale, and the size advantage of the VCSEL chip is maintained while the VCSEL beam quality parameters are changed, so that the array integrated application of the VCSEL chip can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of VCSEL chips, and in particular to a VCSEL chip module, a microlens thereof, and a manufacturing method thereof. Background Art

[0002] VCSEL (Vertical Cavity Surface Emitting Laser) is a vertically emitting semiconductor laser that is widely used in data transmission, 3D sensing, unmanned driving, intelligent vision and other application fields.

[0003] The far-field divergence angle of the VCSEL bare chip is about 20-40°, and the diameter of the light source emission hole is about 10-100μm. The divergence angle and the light emitting aperture parameters can be uniformly referred to as beam quality parameters. The beam quality parameters of the VCSEL bare chip usually cannot meet the actual application requirements. In actual use, the light beam emitted by the chip needs to be shaped. According to application requirements, traditional shaping methods include lenses, microlens arrays, binary diffraction optical elements, etc. The optical elements of these shaping methods all have the characteristics of a large working distance and the need for a fixed bracket structure, which leads to an increase in the volume of the light source module, which is not conducive to the array integration application of VCSEL chips. Summary of the invention

[0004] 1. Technical problem to be solved by the invention

[0005] Optical elements for shaping the light beam emitted by a VCSEL bare chip have a technical problem of occupying a large space. The present invention provides a VCSEL chip module and a microlens and a manufacturing method thereof, which can achieve optimized shaping of the quality parameters of the VCSEL output light beam on a chip scale, maintain the size advantage of the VCSEL chip while changing the VCSEL beam quality parameters, and realize array integrated application of the VCSEL chip.

[0006] 2. Technical solution

[0007] To solve the above problems, the technical solution provided by the present invention is:

[0008] A micro-optical lens includes a micro-lens body, the micro-lens body has at least one optical surface, the optical surface working distance of the micro-lens body is t≥5a, a is the diameter of the light source emission hole; the micro-lens body and the light source emission hole correspond one to one. On the basis of optimizing the beam quality, the size of the optical system is reduced, and it is a chip-level optical lens. The optical lens is integrated with the chip or chip-level packaged, and the chip size is greatly reduced compared with the traditional optical shaping solution; a VCSEL chip with a wider range of light output types is realized.

[0009] Furthermore, when the VCSEL chip body needs to be integrated with the micro-optical lens through a packaging process, the micro-lens body has a plurality of optical surfaces.

[0010] Furthermore, the distance between the light emitting areas d≥2*tan(ω / 2)*t, the light emitting areas have more than one light source emitting hole, and d is the center distance between the two light source emitting holes closest to each other between the two light emitting areas.

[0011] Furthermore, a plurality of the microlens bodies form a microlens array, which corresponds one-to-one to a VCSEL chip array having a plurality of light emitting areas.

[0012] Furthermore, the optical surface is an aspherical surface or a free-form surface.

[0013] A VCSEL chip module comprises a micro-optical lens as described in any one of the above items, and a VCSEL chip body, wherein the micro-lens body is arranged on the side of the VCSEL chip light emitting surface of the VCSEL chip body; the VCSEL chip body has an emitting light area, the emitting light area has more than one light source emitting hole, and the light source emitting holes in one emitting light area are electrically connected in parallel.

[0014] Furthermore, the array arrangement form of the output light areas is a rectangular spliced ​​array of light areas, or a staggered spliced ​​array of light areas.

[0015] Furthermore, when one light source emission hole corresponds to a plurality of optical surfaces, a lens array fixing structure is also included for fixing the microlens body to the VCSEL chip light emitting surface side of the VCSEL chip body.

[0016] A method for manufacturing a VCSEL chip module, comprising: performing optical-grade curved surface processing on a substrate material solidified on a light-emitting surface of a VCSEL chip to obtain a micro-optical lens as described in any of the above items; forming a VCSEL chip module as described in any of the above items, or fixing the produced micro-optical lens as described in any of the above items to a side of the light-emitting surface of a VCSEL chip body through a lens array fixing structure; forming a VCSEL chip module as described in any of the above items.

[0017] 3. Beneficial effects

[0018] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0019] The implementation scheme of the present invention realizes the optimization and shaping of the VCSEL output beam quality parameters on a chip-level scale, maintains the size advantage of the VCSEL chip while changing the VCSEL beam quality parameters, and can realize the array integrated application of the VCSEL chip. On the basis of optimizing the beam quality, the size of the optical system is reduced. It is a chip-level optical lens. The optical lens is integrated with the chip or chip-level packaged. The chip size is greatly reduced compared with the traditional optical shaping solution; a VCSEL chip with a wider range of light output types is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the array of light emission areas of a single light source emission hole;

[0021] Figure 2 It is a schematic diagram of the array of light emission areas of a multi-light source emission hole array;

[0022] Figure 3 It is a schematic diagram of an array of light zones emitted by a multi-emission hole array in another form of staggered splicing of light zones;

[0023] Figure 4 Schematic diagram of the optical path of a microlens on an optical surface;

[0024] Figure 5 A schematic diagram of a light path of a microlens including two optical surfaces;

[0025] Figure 6 is another schematic diagram of a light path of a microlens including an optical surface;

[0026] Figure 7 The second schematic diagram of the optical path of another microlens including an optical surface;

[0027] Figure 8 is a schematic side view of a microlens array on an optical surface;

[0028] Fig. 9 It is a side view schematic diagram of the microlens array of two optical surfaces;

[0029] Fig.10 A side view schematic diagram of a fixing method between the microlens array on two optical surfaces and the VCSEL chip.

[0030] Figure 1-10 , the reference numerals are as follows: 1 is the light emitting area, 2 is the light source emitting hole, 3 is the VCSEL chip body, 31 is the light emitting surface of the VCSEL chip, 32 is the VCSEL chip oxide layer, 321 is the oxide layer of the multi-emitting hole array chip, 4 is the microlens body, 41 is the first optical surface, 42 is the second optical surface, 11 is the first optical surface array, 421 is the second optical surface array, 5 is the emergent light beam, 6 is a schematic diagram of the virtual light source, and 7 is a schematic diagram of the lens array fixing structure. DETAILED DESCRIPTION

[0031] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments.

[0032] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the relevant inventions, rather than to limit the invention. It should also be noted that, for the convenience of description, only the parts related to the invention are shown in the accompanying drawings. The words "first", "second", etc. described in the present invention are set for the convenience of describing the technical solution of the present invention, and have no specific limiting effect. They are all general references and do not constitute a limiting effect on the technical solution of the present invention. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection between the insides of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Multiple technical solutions in the same embodiment, and multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions without contradictions or conflicts, all of which are within the scope of protection required by the present invention.

[0033] Example 1

[0034] Combined with Figure 1-10A micro-optical lens comprises a micro-lens body 4, wherein the micro-lens body 4 has at least one optical surface, and the optical surface working distance t≥5a of the micro-lens body 4, where a is the diameter of the light source emitting hole 2; the micro-lens body 4 and the light source emitting hole 2 correspond one to one. When the working distance of the first optical surface is too large, it will be difficult to realize one optical surface in the process, and a multi-optical surface lens is required at this time. The spacing d≥2*tan(ω / 2)*t of the emitting light area 1, the emitting light area 1 has more than one light source emitting hole 2, and d is the center distance between the two closest light source emitting holes 2 between the two emitting light areas 1. A plurality of the micro-lens bodies 4 form a micro-lens array, which corresponds one to one to a VCSEL chip array having multiple emitting light areas 1. The optical surface is an aspherical surface or a free-form surface.

[0035] In one implementation, a micro-optical lens is added in the light emitting direction of the VCSEL chip, and the micro-optical lens has the following characteristics:

[0036] 1. The clear aperture of the lens can control all outgoing light beams;

[0037] Second, the lens can realize shaping control of the outgoing light of an outgoing light zone 1;

[0038] 3. The lens can form a microlens array, which can correspond one-to-one with the VCSEL chip array having multiple light emission areas 1;

[0039] Fourth, the lens can be obtained by directly processing the optical-grade curved surface on the substrate material cured on the surface of the VCSEL chip, or the independently produced lens or lens array can be cured and integrated with the chip through the packaging structure;

[0040] 5. The lens has at least one optical surface;

[0041] 6. The optical surface of the lens is generally an aspheric surface or a free-form surface. The aspheric surface solution algorithm includes but is not limited to the Cartesian oval surface method, the even-power polynomial correction method, the Zernike polynomial correction method, the Q-type polynomial correction method, etc. The free-form surface is obtained by methods such as Bezier surface, B-spline surface, and non-uniform rational B-spline surface.

[0042] 7. The working distance t of the first optical surface of the lens shall not be less than 5 times the diameter a of the light source emission hole. Figure 4 As shown. For multiple emission holes, it is actually related to the size of the emission light area. But it is also necessarily greater than the working distance for a single emission hole.

[0043] Here, the first optical surface specifically refers to the first optical surface that the light beam passes through after being emitted from the light source emission hole. Here, the working distance of the first optical surface specifically refers to the distance from the light emitting surface of the VCSEL chip to the center point of the first optical surface.

[0044] When the working distance of the first optical surface is too large, it will be difficult to realize one optical surface in the process. In this case, a multi-optical surface lens is required. Aspheric surface is a rotationally symmetric surface, and free-form surface is an asymmetric surface. It is determined by whether the expected output beam quality changes proportionally with the incident beam quality. For example, when the incident beam is changed from a conical cone to an elliptical cone output beam, a free-form surface is required.

[0045] When the VCSEL chip body needs to be integrated with the micro-optical lens through a packaging process, a micro-optical lens of this embodiment is placed on the bare chip that has been processed and produced and does not have an optical lens. The micro-lens body has multiple optical surfaces, and the multiple optical surfaces are packaged on one side of the light-emitting surface of the bare chip through a fixed structure.

[0046] 8. The spacing d between the emission light areas of the multi-emission hole array VCSEL is not less than 2*tan(ω / 2) times the working distance of the first optical surface, where ω is the far-field divergence angle of the VCSEL emission hole, such as Figure 4 , which determines the aperture of the lens. Here, the distance d between the two exit light zones refers specifically to the center distance between the two closest emission holes between the two exit light zones, such as Figure 1-3 shown.

[0047] Example 2

[0048] A VCSEL chip module comprises a micro-optical lens as described in any one of the technical solutions in Example 1, a VCSEL chip body 3, and the microlens body 4 is arranged on the side of the VCSEL chip light-emitting surface 31 of the VCSEL chip body 3; the VCSEL chip body 3 has an emitting light area 1, and the emitting light area 1 has more than one light source emitting hole 2, and the light source emitting holes 2 in an emitting light area 1 are electrically connected in parallel with each other. The array arrangement form of the emitting light area 1 is a rectangular splicing array of light areas, or a staggered splicing array of light areas. When one light source emitting hole 2 corresponds to multiple optical surfaces, it also includes a lens array fixing structure 7 for fixing the microlens body 4 on the side of the VCSEL chip light-emitting surface 31 of the VCSEL chip body 3. That is, it corresponds to one of the implementation methods in Example 1: the microlens body has multiple optical surfaces, and the multiple optical surfaces are encapsulated on the side of the light-emitting surface of the bare chip through a fixing structure, wherein the fixing structure is the lens array fixing structure 7, such as Fig.10 shown.

[0049] In one implementation of this embodiment, the VCSEL bare chip is a chip with a multi-emission hole array, and the chip has the following characteristics:

[0050] 1. The array unit is the light emitting area 1, and the envelope boundary of the light emitting area 1 is a rectangle;

[0051] 2. A light emitting area 1 includes at least one light source emitting hole 2;

[0052] 3. All light source emitting holes 2 in one light emitting area 1 are electrically connected in parallel with each other;

[0053] 4. The electrical connections between the light emitting areas 1 are independent of each other, generally connected to a common cathode;

[0054] 5. The arrangement of the light-emitting area 1 is not unique.

[0055] For the sake of simplicity, one array arrangement is a rectangular splicing array of light zones, such as Figure 1 and 2 Another array arrangement form of the output light area 1 is a light area staggered splicing array, such as Figure 3 ;Right now Figure 1-3 It is a schematic diagram of the array form of the VCSEL chip light output area and the arrangement of the light source emission holes in the light output area; Figure 4 This is a schematic diagram of the light path of a microlens on an optical surface. The microlens has a collimating effect on the light beam. Figure 5 The schematic diagram of the optical path of a microlens including two optical surfaces is shown in FIG. 1 , wherein the microlens has a beam expanding effect on the light beam. Figure 6 This is another schematic diagram of a microlens optical path including an optical surface, where the lens has a beam expansion effect on the light beam. Figure 7 This is another schematic diagram of the optical path of a microlens including an optical surface. The lens has a beam expansion effect on the light beam. Figure 3 A side view schematic diagram of a shaping microlens array of a VCSEL chip for an array of multiple emission light zones; Figure 8 is a schematic side view of a microlens array on an optical surface; Fig. 9 Schematic diagram of the side view of the microlens array on two optical surfaces. Fig.10 A side view schematic diagram of a fixing method between the microlens array on two optical surfaces and the VCSEL chip.

[0056] Example 3

[0057] A method for manufacturing a VCSEL chip module, comprising: performing optical-grade curved surface processing on a substrate material cured on a light-emitting surface 31 of a VCSEL chip to obtain a micro-optical lens as described in any one of the technical solutions in Example 1, and forming a VCSEL chip module as described in any one of the technical solutions in Example 2; or, curing and integrating a micro-optical lens as described in any one of the technical solutions in Example 1 produced on a side of a light-emitting surface 31 of a VCSEL chip body 3 through a packaging structure; that is, the lens can be obtained by directly performing optical-grade curved surface processing on a substrate material cured on the surface of the VCSEL chip, or an independently produced lens or lens array can be cured and integrated with the chip through a packaging structure, the packaging structure and the lens have the same material, and the two are cured by an integrated molding process, that is, a micro-optical lens with a fixed structure is obtained through an integrated molding process, and then the optical lens is cured and integrated with the chip. As one of the implementation methods of this embodiment, Fig.10 As shown: a micro-optical lens described in any technical solution in Example 1 is fixed to one side of the VCSEL chip light-emitting surface 31 of the VCSEL chip body 3 through a lens array fixing structure 7; the lens array fixing structure is only applicable to multi-optical surface lenses, and the actual fixing structure will be integrally formed with the lens array. The fixing structure is slightly larger than the edge of the chip, and the installation requires precise alignment.

[0058] Example 4

[0059] According to any technical solution in Examples 1-3, for a single emission hole array, the lens collimates the single light source emission hole 2: for a VCSEL chip array, the far-field divergence angle of a single light source emission hole 2 is 30° and the diameter is 20μm. There is a light source emission hole 2 in an emission light area 1, located at the center of the emission light area 1. The incident surface of the microlens is in close contact with the light emitting surface 31 of the VCSEL chip body without an air gap. The exit surface of the microlens is an optical surface, which is the first optical surface. The first optical surface is a non-spherical surface, and the surface type value point is calculated by the Cartesian oval method. The design principle of the optical surface is to collimate the light source point. The first optical surface is 150μm away from the light source exit surface, and the distance between the emission light areas is 82μm.

[0060] After the microlens is integrated and processed on the bare chip, the final far-field divergence angle of the chip will become about 10°, the total thickness of the chip will not exceed 0.3mm, and ideally, the light-emitting aperture will become 100μm. This chip can be used in applications that require a small divergence angle and are sensitive to volume, such as distance sensors for consumer devices such as mobile phones.

[0061] Example 5

[0062] According to any technical solution in Examples 1-3, a multi-emission hole array, a lens focuses on the multi-emission holes: for a VCSEL chip array, the far-field divergence angle of a single emission hole is 30° and the diameter is 20μm. There are 56 emission holes in an emission light zone, and the emission hole spacing is 30μm, and the emission light zone is filled with a 7*8 square layout. There is an air gap between the incident surface of the microlens and the light-emitting surface of the VCSEL chip. The incident surface is an optical surface, which is the first optical surface, and the microlens exit surface is an optical surface of another design, which is the second optical surface. The first optical surface and the second optical surface are both aspherical surfaces, and the surface type value points are calculated by the even-power polynomial correction method. The principle of optical surface design is to double the divergence angle of the light source. The first optical surface is 150μm away from the light source exit surface, and the emission light zone spacing is 100μm.

[0063] After the microlens is integrated and packaged on the bare chip, the final far-field divergence angle of the chip will become about 60°, the total thickness of the chip will be no more than 0.4mm, and ideally, the light-emitting aperture will become 10μm. This chip can be used in applications that require high-energy-density light spot arrays, such as the light source of automotive laser radars.

[0064] In summary, the main advantages of the embodiments of the present invention are: the optical lens is integrated with the chip or chip-level packaged, and the chip size is greatly reduced compared with the traditional optical shaping solution; and a VCSEL chip with a wider range of light output types is realized.

[0065] The present invention and its embodiments are described schematically above, and the description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and designs a structural method and an embodiment similar to the technical solution without creativity without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A VCSEL chip module, characterized in that: It comprises a micro-optical lens and a VCSEL chip body, wherein the micro-optical lens comprises a micro-lens body, the micro-lens body has at least one optical surface, and the micro-lens body is arranged on the light emitting surface side of the VCSEL chip body; the VCSEL chip body has an emitting light area, the emitting light area has more than one light source emitting hole, and the light source emitting holes in one emitting light area are electrically connected in parallel with each other; The optical surface working distance t of the microlens body satisfies: t≥5a, and d≥2*tan(ω / 2)*t; wherein a is the diameter of the light source emission hole, d is the center distance between the two light source emission holes closest to each other between the two emission light intervals, and ω is the far-field divergence angle of the VCSEL emission hole; The microlens bodies correspond to the light source emission holes one by one; The microlens body is obtained by directly performing optical-grade curved surface processing on a substrate material that is solidified on the light-emitting surface of a VCSEL chip.

2. A VCSEL chip module according to claim 1, characterized in that: A plurality of the microlens bodies form a microlens array, which corresponds one-to-one to a VCSEL chip array having a plurality of light emitting areas.

3. A VCSEL chip module according to claim 1, characterized in that: The array arrangement form of the output light areas is a rectangular spliced ​​array of light areas, or a staggered spliced ​​array of light areas.

4. A method for manufacturing a VCSEL chip module, characterized in that: include: Optical-grade curved surface processing is performed on the substrate material solidified on the light-emitting surface of the VCSEL chip to obtain a micro-optical lens, thereby forming a VCSEL chip module as described in any one of claims 1 to 3.

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