VCSEL chip and laser radar

Abstract

The utility model belongs to the field of laser module design, and discloses a VCSEL chip and a laser radar, and the VCSEL chip comprises a VCSEL chip body which is configured to be stimulated to radiate laser with a predetermined wavelength; the light uniformizing structure is arranged on the light emitting side of the VCSEL chip body, a micro-lens array is integrated on the side, away from the VCSEL chip body, of the light uniformizing structure, and the laser forms a laser beam with uniform light intensity distribution after penetrating through the light uniformizing structure. Wherein the thickness of the dodging structure is equal to the distance between the light emitting surface of the VCSEL chip and the optical element in the VCSEL chip packaging process. According to the floodlight source, the micro-lens array is directly integrated on the dodging structure at the top of the VCSEL chip, so that the emergent beam meets the irradiance requirement of a traditional floodlight source, the production cost of the floodlight source is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The present application relates to the field of laser module design, and more specifically, to a VCSEL chip and a laser radar. Background Art

[0002] At present, the flood light homogenization technology of the VCSEL (Vertical Cavity Surface Emitting Laser) output beam mainly relies on the combination of different devices. This method involves the production of components in multiple professional fields, such as semiconductor materials, optical components, and electronic circuits. During the production process, these components need to be precisely designed and manufactured to ensure that they can work together to achieve uniform output of the light beam. However, this combination of multiple devices also brings certain challenges. First, the production of different components requires different professional equipment and technologies, which increases the complexity and cost of the production process. Secondly, after the production of these components is completed, it is necessary to fix and package the components through professional assembly production lines, and this step also requires high-precision processes and equipment. Although this combination of multiple devices has improved the freedom and flexibility of the product to a certain extent, it has also significantly increased the production cost, making it difficult to reduce the overall cost of the flood light source. Summary of the invention

[0003] In order to solve the above technical problems, the present application provides a VCSEL chip and a laser radar, by directly integrating a microlens array on the light homogenization structure on the top of the VCSEL chip in the present application, the thickness of the light homogenization structure is the same as the distance between the light emitting surface of the VCSEL chip and the optical element in the VCSEL chip packaging process, so that the emitted light beam meets the irradiance requirements of the traditional floodlight source, reduces the production cost of the floodlight source, and improves the production efficiency. Specifically, the technical solution of the present application is as follows:

[0004] The present application discloses a VCSEL chip, comprising: a VCSEL chip body, configured to stimulate the emission of laser light of a predetermined wavelength;

[0005] A light homogenizing structure is arranged on the light emitting side of the VCSEL chip body, and a microlens array is integrated on the side of the light homogenizing structure away from the VCSEL chip body. The laser forms a laser beam with uniform light intensity distribution after passing through the light homogenizing structure;

[0006] The thickness of the light homogenizing structure is the same as the distance between the light emitting surface of the VCSEL chip and the optical element in the VCSEL chip packaging process.

[0007] In some embodiments, the VCSEL chip body includes a growth substrate and a first reflector layer, a photoelectric confinement layer, an active layer, and a second reflector layer sequentially disposed on the growth substrate.

[0008] In some embodiments, the VCSEL chip packaging process includes any one of a COB packaging process, a TO packaging process, a SMD packaging process or a COS packaging process.

[0009] Furthermore, the light homogenization structure is attached to the VCSEL chip body directly or via an intermediate layer, and the intermediate layer is optically transparent in the wavelength region where the laser is located.

[0010] In some embodiments, the light homogenizing structure is made of any one of glass, gallium arsenide or silicon.

[0011] Furthermore, the microlens array and the light homogenization structure are an integrated structure;

[0012] The microlens array is obtained by repeatedly arranging microlenses of a basic optical surface type; the optical surface type of the microlens includes: a spherical surface, an aspherical surface, or a free-form surface.

[0013] In some embodiments, the optical element includes a light homogenizing lens or a collimating lens.

[0014] In some embodiments, the divergence angle of the laser light in the light homogenizing structure is smaller than the divergence angle of the laser light emitted into the air.

[0015] In some embodiments, the light-clearing aperture of the microlens is smaller than the light-exiting aperture of the VCSEL chip body.

[0016] In a second aspect, the present application also discloses a laser radar, which includes a driving circuit, a detection component and a transmitting component; wherein the transmitting component at least includes the VCSEL chip described in any one of the above embodiments.

[0017] Compared with the prior art, this application has at least the following beneficial effects:

[0018] The present application proposes a new VCSEL chip, and on the basis of the VCSEL chip of the present application, a microlens structure is integrated, and the thickness of the light-homogenizing structure is the same as the distance between the light-emitting surface of the VCSEL chip and the optical element in the VCSEL chip packaging process, so that the emitted light beam meets the irradiance requirements of the traditional floodlight source. The VCSEL chip provided by the present application is an integrated one-piece structure, which eliminates the complex packaging steps in the production process, thereby reducing additional production costs and improving production efficiency. In addition, reducing the packaging steps also helps to improve the reliability and consistency of the product, and promotes the widespread application of floodlight source technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The preferred implementation scheme will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present application.

[0020] Figure 1 It is a structural schematic diagram of a floodlight source in the prior art;

[0021] Figure 2 This is a schematic diagram of the structure of a VCSEL chip in the embodiment provided in this application.

[0022] Description of reference numerals:

[0023] 10 - light homogenization structure; 11 - microlens array; 20 - VCSEL chip body; 21 - first reflector layer; 22 - photoelectric limiting layer; 23 - active layer; 24 - second reflector layer; 30 - growth substrate. DETAILED DESCRIPTION

[0024] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, and circuits are omitted to prevent unnecessary details from obstructing the description of the present application.

[0025] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections.

[0026] In order to simplify the drawings, only the parts related to the utility model are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0027] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0028] In this document, it should be noted that, 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 the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0029] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the specific implementation methods of the present application will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0031] In the current field of optoelectronics, VCSEL (Vertical Cavity Surface Emitting Laser) is an efficient light source with an increasingly wide range of applications. However, in order to achieve a wider range of applications, especially in situations where uniform beam output is required, such as lighting, projection, and sensing, it is particularly important to homogenize the VCSEL output beam. Existing technical routes mainly rely on a combination of different devices to achieve this goal. Specifically, this involves the production of components in multiple professional fields, such as semiconductor materials, optical components, electronic circuits, etc. Each component needs to be precisely designed and manufactured to ensure that they can work together to achieve uniform beam output.

[0032] During the production process, these components need to undergo strict quality control and testing to ensure that their performance meets the requirements. After the production of these components is completed, they need to be fixed and packaged through professional assembly production lines. Figure 1 As shown, Figure 1 This is a schematic diagram of a conventional floodlight source structure in the prior art, which is assembled by a chip packaging process using three components: a packaging substrate, a VCSEL chip, and an optical element, wherein the optical element includes a diffuser lens or a collimator lens.

[0033] VCSEL chip packaging processes include any one of the COB packaging process, TO packaging process, SMD packaging process or COS packaging process. The production of this light source component requires not only high-precision processes and equipment, but also strict operating specifications and quality control to ensure the reliability and consistency of the final product. However, although this multi-device combination method has improved the freedom and flexibility of the product to a certain extent, it has also significantly increased the production cost. The multi-device combination method increases the complexity of the supply chain. At the same time, if the component needs to be replaced, redesign and testing are required. From the production of components to the assembly of the final product, each step requires a lot of manpower, material and financial resources.

[0034] Therefore, in order to reduce the cost of floodlight sources and improve production efficiency and innovation capabilities, this application proposes a new VCSEL chip, and on the basis of the VCSEL chip of this application, a microlens structure is integrated to make the outgoing light beam meet the irradiance requirements of traditional floodlight sources. The VCSEL chip provided in this application is an integrated one-piece structure, which eliminates the complex packaging steps in the production process, thereby reducing additional production costs and improving production efficiency. In addition, reducing the packaging steps also helps to improve the reliability and consistency of the product, and promotes the widespread application of floodlight source technology.

[0035] Specifically, an embodiment of a VCSEL chip provided in the present application includes: a VCSEL chip body and a light homogenizing structure arranged on a light emitting side of the VCSEL chip body.

[0036] The VCSEL chip body is configured to stimulate the emission of laser light of a predetermined wavelength.

[0037] A light homogenizing structure is arranged on the light emitting side of the VCSEL chip body. A microlens array is integrated on the side of the light homogenizing structure away from the VCSEL chip body. The laser forms a laser beam with uniform light intensity distribution after passing through the light homogenizing structure.

[0038] The thickness of the light homogenizing structure is the same as the distance between the light emitting surface of the VCSEL chip and the optical element in the VCSEL chip packaging process.

[0039] The material of the light homogenizing structure is any one of glass, gallium arsenide or silicon.

[0040] The thickness of the light homogenization structure is a specified thickness, and the thickness is related to the distance between the light emitting surface of the VCSEL chip and the diffusion plate in the original packaging method. The specified thickness makes the distance between the microlens array and the VCSEL chip body fixed.

[0041] Specifically, the VCSEL chip body in this embodiment is a VCSEL chip structure. Based on this application, the technical effect described in this application can also be achieved by using VCSEL chips in the prior art or by adaptively modifying the existing VCSEL chips.

[0042] In this embodiment, the thickness of the light-homogenizing structure is related to the distance between the light-emitting surface of the VCSEL chip and the lens in the original packaging method. At a specified thickness, the distance between the microlens array integrated on the first side of the light-homogenizing structure and the light-emitting hole of the VCSEL chip is a specified distance. Optionally, the thickness of the light-homogenizing structure will affect the divergence angle of the light beam. The closer the microlens array is to the laser source, the smaller the divergence angle of the shaped light beam and the more concentrated the light spot; the farther the distance, the larger the divergence angle and the more dispersed the light spot.

[0043] When designing a VCSEL chip, the placement distance of the microlens array affects the uniformity of the light beam in space. An appropriate distance can ensure uniform distribution of the light beam on the target plane, while an improper distance may cause uneven light spots or hot spots. The design and placement distance of the microlens array jointly determine the effect of beam shaping. The thickness of the homogenization structure, that is, the distance between the microlens array and the laser source, needs to be precisely controlled to ensure the homogenization quality of the light beam. The closer the actual incident light is to collimated light, the closer the final effect will be to the design goal, which will be more beneficial to the microlens design.

[0044] In one implementation of this embodiment, the main part of the light homogenization structure is directly epitaxially grown on the VCSEL chip, and then a microlens array is processed on one side of the light homogenization structure. Specifically, the main part of the light homogenization structure serves as the top substrate of the VCSEL chip body and is integrally connected to the VCSEL chip body.

[0045] In another implementation of this embodiment, the light homogenization structure is attached to the VCSEL chip body directly or via an intermediate layer, and the intermediate layer is optically transparent in the wavelength region where the laser is located.

[0046] In this embodiment, the VCSEL chip body and the light homogenizing structure are not an integrated structure, and the middle layer is used to bond the VCSEL chip body and the light homogenizing structure; after the connection is completed, a microlens array is then processed on one side of the light homogenizing structure. The material of the middle layer can be optical epoxy resin, or other materials that can achieve the same effect.

[0047] Specifically, in another embodiment of a VCSEL chip provided by the present application, the VCSEL chip body 20 includes a growth substrate and a first reflector layer 21, a photoelectric limiting layer 22, an active layer 23 and a second reflector layer 24 which are sequentially arranged on the growth substrate.

[0048] Reference Manual Attached Figure 2 In this embodiment, the VCSEL chip includes the following components connected from top to bottom:

[0049] A light homogenizing structure 10 is provided, wherein a microlens array 11 is integrated on a first side of the light homogenizing structure 10 to help control the emission direction and beam quality of the laser generated by the shaped VCSEL.

[0050] The first reflector layer 21 is located on the second side of the light homogenizing structure 10. It serves as the top reflector of the laser cavity. Specifically, the first reflector layer 21 is a P-type distributed Bragg reflector (PDBR). The P-type doped Bragg reflector has a positive doping characteristic. Under the action of an external electric field, its majority carriers are holes and are positively charged.

[0051] Photoelectric limiting layer 22, specifically, the composition of the photoelectric limiting layer can be an oxide layer (Oxide). The insulating layer is formed by the oxidation process to control the distribution of current and light. The photoelectric limiting layer 22 is obtained by oxidizing AlGaAs material with a high aluminum component, and its material is usually aluminum oxide. In other embodiments, other common oxide layer materials can also be used.

[0052] The active layer 23 is formed by alternately stacking a plurality of thin quantum well layers and thicker barrier layers. When excited, the electrons and holes in the quantum well layers will recombine to generate laser light of a predetermined wavelength.

[0053] The second reflector layer 24 is located below the active layer 23 and serves as the bottom reflector of the laser cavity, and forms a laser cavity together with the first reflector layer 21. Specifically, the second reflector layer 24 is an N-type distributed Bragg reflector (NDBR). Unlike the P-type doped Bragg reflector, the N-type doped Bragg reflector has a negative doping characteristic. Under the action of an external electric field, its majority carriers are electrons and are negatively charged. In this embodiment, the P-type doped Bragg reflector serves as the top reflector of the VCSEL chip body. The N-type doped Bragg reflector serves as the bottom reflector of the VCSEL chip body. The two form the laser cavity. The laser generated by the active layer 23 is reflected and enhanced multiple times in the laser cavity.

[0054] The growth substrate 30 provides the necessary physical support for the VCSEL chip, ensuring the stability and mechanical strength of the chip during processing and use. In addition, the growth substrate 30 is also used for the growth and deposition of semiconductor materials in the VCSEL chip body. The growth substrate 30 is arranged at the bottom of the second reflector layer 24, and can also participate in the electrical circuit of the device, forming a good ohmic contact with the semiconductor material, which is convenient for the injection of current. The growth substrate 30 in this specific embodiment can be gallium arsenide or silicon.

[0055] Optionally, the Bragg reflector layer in this embodiment forms multiple reflective interfaces by periodically stacking high-refractive index and low-refractive index material layers, and uses the interference effect of light to enhance the reflectivity, thereby achieving high reflection at a specific wavelength, while the reflectivity of light at other wavelengths is low, which helps the VCSEL chip work at a specific wavelength and reduces mode competition. By adjusting the number and thickness of the reflector layer, the mode and divergence angle of the laser can be controlled to optimize the quality of the laser beam.

[0056] In some other embodiments of the present application, the first reflector layer and the second reflector layer are composed of other types of reflector materials, which can also provide carriers under the action of an external power source and form a laser cavity effect, which is not limited in the present application. Of course, the use of other types of reflector layers as a replacement for the first reflector layer and the second reflector layer in the present application should also be within the scope of protection of the present application.

[0057] In another embodiment of a VCSEL chip of the present application, based on any of the above embodiments, the microlens array and the light homogenization structure are an integrated structure. The laser beam is formed with uniform light intensity distribution after passing through the light homogenization structure and the microlens array.

[0058] As the instruction manual Figure 2As shown, specifically, the microlens array is obtained by processing the first side of the light homogenizing structure by etching, hot melting or nano-engraving methods.

[0059] Furthermore, a microlens array is directly processed on the light homogenizing structure to make the outgoing light beam meet the irradiance requirements of a traditional floodlight source. The microlens curved surface structure can be obtained on the substrate by methods such as focused ion beam etching technology, wet etching technology, photoresist hot melt method, nano-engraving finishing, etc.

[0060] The divergence angle of the laser in the light homogenization structure is smaller than the divergence angle of the laser emitted into the air. Since the size of the microlens is extremely small, considering the actual processing error, an optical surface can be used in the actual design to optimize the design for collimated incident light. The closer the actual incident light is to collimated light, the closer the final effect will be to the design goal, which will be more beneficial for the microlens design. This method can be used to achieve the traditional floodlight effect at the chip production end, thereby effectively reducing production costs and improving production efficiency.

[0061] In another embodiment of the present application, based on any of the above embodiments, a microlens array is designed in which the divergence angle of the light beam inside the substrate is much smaller than the divergence angle when emitted into the air. The divergence angle of the laser emitted from the VCSEL into the air is about 20°, and the divergence angle in the uniform light structure 10 is about 6°.

[0062] Specifically, the divergence angle of the laser beam in the light homogenizing structure 10 is related to its material. The emission angle of the laser beam emitted into the air is related to the optical surface of the microlens array. The microlens array is obtained by repeatedly arranging microlenses of a basic optical surface. The optical surface of the microlens includes: spherical, aspherical, or free-form surface.

[0063] In one embodiment, a set of basic surface shapes can be obtained from the energy distribution of the outgoing light beam, and the basic surface shapes are randomly expanded to obtain a complete microlens array as the overall curved surface shape. The random array of the basic surface shape is mainly based on the microlens aperture.

[0064] The optical surface of the microlens usually requires a precise manufacturing process to achieve. In some embodiments, the optical surface of the microlens can be designed as an aspherical surface. The aspherical 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. In other embodiments, the optical surface of the microlens can be designed as a free-form surface. The free-form surface is obtained by methods such as Bezier surface, B-spline surface, and non-uniform rational B-spline surface.

[0065] Different types of optical surfaces bring different beam shaping effects. For example, aspheric lenses can correct spherical aberration, while free-form surface designs can be used for special applications, such as diffusing beams in a specific direction. Different applications may have different requirements for the aperture and optical surface of the microlens. In practical applications, the appropriate aperture and basic optical surface should be selected according to the specific scenario.

[0066] In another embodiment of the present application, based on any of the above embodiments, the microlens array is designed, and the light aperture of the microlens needs to be smaller than the light exit aperture of the VCSEL. In one implementation of this embodiment, the light exit aperture of the designed VCSEL chip is 20um, and the light aperture scale of the microlens is 5-10um.

[0067] Specifically, the light exit hole of VCSEL, also called the emission hole or oxide hole, is one of the key parameters in the VCSEL chip that affects its optical performance. The size of the light exit hole is determined by the oxide layer. Under specific conditions of the oxide layer, the surface of the semiconductor material is partially converted into oxide. The light exit hole defines the physical aperture of the light beam emitted by the laser cavity. By limiting the light field, the divergence angle and beam quality of the laser can be controlled. Optionally, the light exit hole also limits the current injected into the active area, which helps to control the luminous efficiency of the laser cavity.

[0068] Clear aperture: refers to the diameter of the microlens that allows light to pass through. Microlenses with larger apertures can collect more light, thereby providing a larger beam or higher luminous flux. The optical surface design of the microlens array may affect the diffusion or shaping characteristics of light when passing through the microlens, thereby affecting the size of the clear aperture of the microlens array. When designing a microlens array, it is necessary to consider the matching of the microlens aperture and the optical surface to ensure that the light within the entire aperture range can be properly diffused or shaped.

[0069] Based on the same concept, the present application also discloses: a laser radar, which includes a driving circuit, a detection component and a transmitting component; wherein the transmitting component at least includes the VCSEL chip described in any one of the above embodiments.

[0070] The transmitting component is used to generate and transmit laser pulses. The detecting component is used to receive the laser pulses reflected from the target object and measure the time it takes for these pulses to return. The driving circuit is used to provide the electrical signals required by the VCSEL chip to ensure the stable and efficient operation of the VCSEL chip.

[0071] In other embodiments, the laser radar, in addition to the above components, also includes important components such as a data processing and storage unit and a communication unit. These components and structures together constitute a complete laser radar system, enabling it to perform high-precision distance measurement and imaging.

[0072] A VCSEL chip and a laser radar in the present application have the same technical concept, and the technical details of the embodiments of the two are applicable to each other. In order to reduce repetition, they will not be repeated here.

[0073] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0074] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0075] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A VCSEL chip, characterized in that: include: The VCSEL chip body is configured to stimulate the emission of laser light of a predetermined wavelength; A light homogenizing structure is arranged on the light emitting side of the VCSEL chip body, and a microlens array is integrated on the side of the light homogenizing structure away from the VCSEL chip body. The laser forms a laser beam with uniform light intensity distribution after passing through the light homogenizing structure; The thickness of the light homogenizing structure is the same as the distance between the light emitting surface of the VCSEL chip and the optical element in the VCSEL chip packaging process.

2. A VCSEL chip according to claim 1, characterized in that: The VCSEL chip body comprises a growth substrate and a first reflector layer, a photoelectric limiting layer, an active layer and a second reflector layer which are sequentially arranged on the growth substrate.

3. The VCSEL chip according to claim 1, characterized in that: The VCSEL chip packaging process includes any one of a COB packaging process, a TO packaging process, a SMD packaging process or a COS packaging process.

4. The VCSEL chip according to claim 2, characterized in that: The light homogenizing structure is attached to the VCSEL chip body directly or via an intermediate layer, and the intermediate layer is optically transparent in the wavelength region where the laser is located.

5. The VCSEL chip according to claim 1, characterized in that: The material of the light homogenizing structure is any one of glass, gallium arsenide or silicon.

6. The VCSEL chip according to claim 1, characterized in that: The microlens array and the light homogenizing structure are an integrated structure; The microlens array is obtained by repeatedly arranging microlenses of a basic optical surface type; The optical surface of the microlens includes: a spherical surface, an aspherical surface, or a free-form surface.

7. The VCSEL chip according to claim 1, characterized in that: The optical element includes a light homogenizing lens or a collimating lens.

8. The VCSEL chip according to any one of claims 1 to 7, characterized in that: The divergence angle of the laser in the light homogenizing structure is smaller than the divergence angle of the laser emitted into the air.

9. The VCSEL chip according to any one of claims 1 to 7, characterized in that: The light-clearing aperture of the microlens is smaller than the light-emitting aperture of the VCSEL chip body.

10. A laser radar, characterized in that: The laser radar includes a driving circuit, a detection component and a transmitting component; wherein the transmitting component includes at least one VCSEL chip as described in any one of claims 1-9.

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