Gradient Vcsel laser

Abstract

A gradient Vcsel laser is characterized in that an anode bonding pad is arranged on the outer side of the upper surface, array light-emitting holes are formed in the center area, and a cathode bonding pad is arranged at the bottom; the surface of the light-emitting hole is covered with a polarization wire grating, and the gain of the Vcsel hole resonant cavity is modulated through the direction of the polarization wire grating, so that the brightness gradient is realized. According to the utility model, the polarization wire grating with the gradually changing direction is integrated on the surface of the light-emitting hole, and the modulation effect of the polarization wire grating on the gain of the Vcsel resonant cavity is utilized, so that the brightness gradient control on the single-chip level is realized, additional external optical elements are not needed, and diversified requirements can be met.

Description

Technical Field

[0001] This utility model relates to the field of VCSEL laser technology, specifically to a gradient VCSEL laser. Background Technology

[0002] Vertical-cavity surface-emitting lasers (VCSELs), as important semiconductor lasers, possess advantages such as low threshold current, circular output beam, and two-dimensional integration capabilities, and are widely used in fields such as optical communication, 3D sensing, and LiDAR. However, traditional VCSEL arrays face the following technical challenges in practical applications:

[0003] 1. Application Limitations Due to Uniform Emission: In traditional VCSEL arrays, the output power and polarization characteristics of each emitting unit are typically uniform. However, in many emerging applications (such as structured light projection, 3D depth sensing, and beam shaping), spatial modulation of the light field is required, for example, generating specific brightness gradients, spot profiles, or polarization distributions. Traditional uniformly emitting VCSEL arrays cannot directly meet these requirements and often require additional optical components (such as diffractive optical elements (DOE), polarizers, etc.) for secondary modulation, leading to increased system complexity, higher costs, and potentially introducing additional energy losses.

[0004] 2. The Coupling Challenges of Polarization Control and Resonant Cavity Gain: The output polarization characteristics of VCSELs are crucial to their application performance. For example, in some 3D sensing systems, beams with specific polarization directions are required to improve anti-interference capabilities. However, the polarization direction of traditional VCSELs is usually determined by the randomness of the manufacturing process, making precise control difficult, and the polarization consistency between different light-emitting units is poor. Furthermore, the coupling relationship between resonant cavity gain and polarization direction is complex. How to achieve precise modulation of luminous intensity through polarization control is a technical problem that urgently needs to be solved in this field.

[0005] 3. Challenges of Integration and Miniaturization: As consumer electronics, autonomous driving, and other fields increasingly demand miniaturization and integration of 3D sensing systems, the traditional separate design of VCSELs and external optical components is gradually becoming a bottleneck. Developing a VCSEL technology that can directly achieve brightness gradation and polarization control at the chip level is of great significance for simplifying system architecture, reducing costs, and improving reliability.

[0006] The above background information is provided only to aid in understanding the inventive concept and technical solution of this utility model. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Utility Model Content

[0007] Therefore, this invention integrates a polarization grid with a gradually changing direction on the surface of the light-emitting hole, and utilizes the modulation effect of the polarization grid on the gain of the Vcsel resonant cavity to achieve brightness gradient control at the single-chip level, without the need for additional external optical components, and can meet diverse needs.

[0008] This utility model provides a gradient VCSEL laser, characterized in that the outer side of the upper surface is an anode pad, the central area is an array of light-emitting holes, and the bottom is a cathode pad;

[0009] The surface of the light-emitting aperture is covered with a polarization grid. The gain of the Vcsel aperture resonant cavity is modulated by the direction of the polarization grid, thereby achieving a gradual change in brightness.

[0010] Optionally, the gradient VCSEL laser is characterized in that the anode pad has a ring structure and is arranged around the array of light-emitting holes, and the width of the anode pad is between 0.5mm and 2mm, so as to optimize the current distribution and improve the working stability of the laser.

[0011] Optionally, the gradient VCSEL laser is characterized in that the array of light-emitting holes is arranged in a regular rectangular array, and the spacing between adjacent light-emitting holes is between 10μm and 50μm.

[0012] Optionally, the gradient VCSEL laser is characterized in that the cathode pad has a planar structure with an area larger than that of the anode pad, and the cathode pad is tightly connected to the substrate by conductive adhesive or a metal welding layer to ensure good electrical connection and heat dissipation performance.

[0013] Optionally, the graded VCSEL laser is characterized in that the polarization grating is made of a metallic material, wherein the metallic material is one or more of aluminum, gold, or copper, and the linewidth of the polarization grating is between 50 nm and 100 nm, and the line spacing is between 100 nm and 200 nm.

[0014] Optionally, the gradient VCSEL laser is characterized in that the direction of the polarization grating is set at a certain angle to the axis of the light-emitting aperture, and the angle is between 0° and 45°.

[0015] Optionally, the gradient VCSEL laser is characterized in that the linewidth and spacing of the polarization grids on the surfaces of at least two of the array of light-emitting holes are different.

[0016] Optionally, the gradient VCSEL laser is characterized in that both the anode pad and the cathode pad are provided with pins for connecting to external circuits, the pins are made of metal and the pin surfaces are plated with gold or nickel.

[0017] Optionally, the gradient VCSEL laser is characterized in that the number of pins on the anode pad is related to the number of rows or columns of the array of light-emitting holes. When the array of light-emitting holes has m rows and n columns, the number of pins on the anode pad is m+n-1. By connecting different combinations of pins, independent control of different groups and regions of the array of light-emitting holes can be achieved, further optimizing the brightness gradient effect.

[0018] Optionally, the gradient VCSEL laser is characterized by further comprising an encapsulation layer disposed on the outer side of the upper surface, the encapsulation layer being made of transparent or semi-transparent epoxy resin, silicone or glass material, and the encapsulation layer completely covering the anode pad, the array light-emitting aperture and the polarization grid.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] In this invention, the polarization grating can be integrated with the VCSEL manufacturing process through standard photolithography without significantly altering existing production processes. This invention achieves modulation directly at the light source level, resulting in high energy efficiency and avoiding energy loss from external optical components. By designing the directional distribution of the polarization grating, this invention provides precise and controllable control over the brightness gradient curve. This invention integrates polarization control and brightness modulation functions within the chip, achieving high integration and contributing to system miniaturization. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort. Other features, objects, and advantages of this utility model will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0022] Figure 1 This is a schematic diagram of the planar structure of a gradient VCSEL laser according to an embodiment of the present invention;

[0023] Figure 2 This is a cross-sectional structural diagram of a gradient VCSEL laser according to an embodiment of the present invention.

[0024] 1-Array laser;

[0025] 2-Light-emitting aperture area;

[0026] 3-Anode pads;

[0027] 4-Cathode pad; Detailed Implementation

[0028] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0029] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the utility model described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] This utility model provides a gradient VCSEL laser, which aims to solve the problems existing in the prior art.

[0031] The technical solutions of this utility model and this application solve the above-mentioned technical problems in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this utility model will now be described with reference to the accompanying drawings.

[0032] like Figure 1 and Figure 2 As shown, the graded VCSEL laser 1 in this embodiment of the present invention includes:

[0033] The outer side of the upper surface is an anode pad, the central area is an array of light-emitting holes, and the bottom is a cathode pad;

[0034] The surface of the light-emitting aperture is covered with a polarization grid. The gain of the Vcsel aperture resonant cavity is modulated by the direction of the polarization grid, thereby achieving a gradual change in brightness.

[0035] Specifically, the anode pad is the positive interface connecting the laser to external circuitry. In the circuit, it serves to introduce current, providing the necessary electrical input for the laser's normal operation. When the positive terminal of the external power supply is connected to the anode pad, current flows through the pad into the laser, driving the electron-hole recombination process inside the laser, thereby generating photon emission. It is typically made of a highly conductive metal, such as gold (Au) or copper (Cu). These metals have low resistivity, reducing current loss during transmission. Its structural design generally prioritizes good contact with external circuitry, typically featuring a large contact area to ensure a stable electrical connection.

[0036] The array of emission apertures is the core area for laser emission in a VCSEL laser. Each aperture can be considered an independent laser emitting unit. When current is injected, electron-hole recombination occurs in the semiconductor material inside the aperture, releasing photons. These photons are reflected back and forth within the resonant cavity, forming stimulated emission amplification, and finally emitting laser light from the aperture. The design of the array of emission apertures can increase the total output power of the laser, and different beam modes and output characteristics can be achieved through reasonable layout.

[0037] The light-emitting apertures are generally in regular shapes such as circles or squares, and their size is usually on the order of micrometers. Multiple light-emitting apertures are distributed in a certain arrangement (such as rectangular arrays, hexagonal arrays, etc.) in the central region of the upper surface. This array layout can optimize the light field distribution and heat distribution of the laser, and improve the performance and reliability of the laser.

[0038] A polarization grating is a key component used to modulate the gain of a VCSEL aperture resonator. Its direction controls the polarization state of the laser, thereby achieving a gradual change in brightness. In a laser, the polarization grating alters the propagation characteristics of light within the resonator, producing different losses or gains for light with different polarization directions. When the direction of the polarization grating matches the polarization direction of the light, the gain of light with that polarization direction increases within the resonator, making it easier to emit; conversely, when they do not match, the gain decreases, making light difficult to emit. By rationally designing the direction and distribution of the polarization grating, lasers with varying brightness can be emitted from apertures at different locations, achieving a gradual brightness effect.

[0039] Polarization gratings typically consist of a series of parallel metal lines or dielectric strips. The width, spacing, and orientation of these lines can be precisely controlled according to design requirements. The manufacturing process must ensure the uniformity and consistency of the lines to guarantee a stable and reliable polarization modulation effect on light.

[0040] The cathode pad is the negative interface connecting the laser to external circuitry. It works in conjunction with the anode pad to form a complete current loop. When the negative terminal of an external power supply is connected to the cathode pad, current flows from the anode pad into the laser, passes through the internal circuitry, and then flows out of the cathode pad, completing the current cycle and providing continuous power for the laser's normal operation. Similar to the anode pad, the cathode pad is typically made of a highly conductive metal. Its structural design also emphasizes good contact with external circuitry to ensure a stable electrical connection and allow current to flow smoothly into and out of the laser.

[0041] In some embodiments, the anode pad has a ring structure and is arranged around the array of light-emitting holes, and the width of the anode pad is between 0.5mm and 2mm to optimize current distribution and improve the working stability of the laser.

[0042] The anode pads are arranged in a ring around the array of light-emitting holes, a layout that offers several advantages. From a current introduction perspective, the ring structure allows current to flow evenly into the array of light-emitting holes from multiple directions. Since the array of light-emitting holes is the core area for laser emission, uniform current injection ensures that each hole receives a relatively consistent current supply, preventing malfunctions caused by uneven current distribution, such as inconsistent brightness or low luminous efficiency. Simultaneously, this ring-shaped structure also helps reduce localized current concentration during transmission, mitigating the thermal effects caused by current concentration and protecting the internal structure of the laser from overheating damage.

[0043] The annular anode pad is closely positioned to the array of light-emitting holes, forming a complete current introduction system. This design makes the laser more compact and rational in its overall structure, facilitating connection and integration with other external circuits, and also making the laser easier to install and use in various application scenarios.

[0044] The width of the anode pads is between 0.5mm and 2mm, a range carefully designed and experimentally verified. Within this range, the current distribution on the pads is effectively optimized. If the pads are too narrow, the current transmission may experience a large voltage drop due to higher resistance, leading to uneven current distribution and affecting the normal operation of the light-emitting apertures. Conversely, while a wider pad can reduce resistance, it increases the space occupied by the pads, hindering the miniaturization and integration of the laser design. A width of 0.5mm-2mm ensures uniform current distribution while also meeting the size requirements of the laser.

[0045] A suitable pad width contributes to improved laser operational stability. Uniform current distribution reduces laser output instability caused by current fluctuations, such as laser power jitter and beam quality degradation. Simultaneously, stable current transmission reduces internal thermal and electrical noise, improving the laser's signal-to-noise ratio and reliability, and extending its lifespan. In practical applications, this range of anode pad widths enables lasers to maintain stable performance output under various operating conditions, meeting the stability requirements of different fields.

[0046] In some embodiments, the array of light-emitting holes is arranged in a regular rectangular array, and the spacing between adjacent light-emitting holes is between 10μm and 50μm.

[0047] The array of light-emitting apertures uses a regular rectangular array arrangement, which offers significant advantages in optical performance. The rectangular array allows for uniform distribution and effective control of the light field, enabling better superposition and coupling of laser beams emitted from each aperture. A well-designed rectangular array layout can optimize the laser beam pattern, for example, by creating a more uniform and concentrated spot, thus improving beam quality. This is crucial for applications requiring high-precision, high-energy-density laser output, such as laser processing and laser communication.

[0048] From a thermal management perspective, rectangular array arrangements help improve the heat dissipation efficiency of lasers. During laser operation, the emission apertures generate a significant amount of heat. If this heat cannot be dissipated in time, the aperture temperature will rise, affecting the laser's performance and lifespan. Rectangular array arrangements ensure a relatively regular spatial distribution between the emission apertures, facilitating the design of effective heat dissipation structures and channels, such as heat sinks and heat pipes. This allows for rapid heat conduction, keeping the emission apertures within a suitable operating temperature range, thereby improving the laser's stability and reliability.

[0049] The rectangular array arrangement is also compatible with laser manufacturing processes. In semiconductor manufacturing, the rectangular array layout makes it easier to achieve precise positioning and processing through processes such as photolithography and etching, ensuring the size and positional accuracy of each light-emitting aperture and improving the manufacturing yield and consistency of the laser. At the same time, this arrangement also facilitates integration and assembly with other optical components, reducing manufacturing difficulty and cost.

[0050] The spacing between adjacent emission apertures is between 10μm and 50μm, a range carefully designed and optimized. Appropriate spacing controls the coupling and interference effects between the laser beams emitted from each aperture. If the spacing is too small, the interference between lasers may be too strong, leading to an uneven light field distribution and alternating bright and dark interference fringes, affecting the laser beam quality and output stability. Conversely, if the spacing is too large, the coupling between lasers will weaken, failing to fully utilize the advantages of the array of emission apertures and making it difficult to achieve high-brightness, high-power laser output. A spacing of 10μm-50μm allows for moderate coupling and interference between lasers, forming a uniform and stable light field distribution, thus improving the overall performance of the laser.

[0051] The spacing was also designed to balance power density and thermal effects. A smaller spacing increases the number of apertures per unit area, thereby improving the laser's power density. However, too many apertures concentrated in a small area can exacerbate thermal effects and increase the difficulty of heat dissipation. A spacing of 10μm-50μm can ensure a certain power density while avoiding severe thermal effects caused by overly dense apertures, ensuring that the laser maintains stable performance output during long-term operation.

[0052] Different applications have different performance requirements for lasers, and a pitch range of 10μm-50μm can meet a variety of application needs. In some applications that require high-resolution imaging or fine processing, a smaller pitch can achieve a denser beam distribution, improving the accuracy of imaging or processing; while in some applications that require high-power laser output, a larger pitch can increase the number of light-emitting holes while ensuring heat dissipation, thereby increasing the total output power of the laser.

[0053] In some embodiments, the cathode pad has a planar structure with an area larger than that of the anode pad, and the cathode pad is tightly connected to the substrate by conductive adhesive or a metal welding layer to ensure good electrical connection and heat dissipation performance.

[0054] The cathode pads employ a planar structure, a design that offers significant advantages in manufacturing and installation. From a manufacturing perspective, the planar structure is relatively simple, facilitating precise dimensional and shape control through common semiconductor manufacturing processes (such as photolithography and deposition), reducing manufacturing difficulty and cost, and improving production efficiency. During installation, the planar structure facilitates bonding and connection to external circuits or heat dissipation devices, eliminating the need for complex positioning and fixing structures, reducing uncertainties and errors during installation, and improving installation reliability and stability.

[0055] The planar structure helps achieve a uniform current distribution on the cathode pad. After the current flows into the cathode pad from the external circuit, the planar structure allows the current to diffuse over a larger area, avoiding current concentration in local areas. This reduces the resistance and thermal effects caused by current concentration, ensuring that the current flows into the laser stably and uniformly, providing reliable electrical support for the normal operation of the laser.

[0056] The larger area of ​​the cathode pad compared to the anode pad has a significant impact on electrical performance. A larger area means lower resistance, as resistance is inversely proportional to the cross-sectional area of ​​a conductor. During current transmission, lower resistance reduces voltage drop, lowers energy loss, and improves current transmission efficiency. Simultaneously, the larger cathode pad area can accommodate more current, meeting the laser's current requirements under different operating conditions and ensuring the laser's stability and reliability at high power output.

[0057] From a heat dissipation perspective, a larger cathode pad area increases the contact area with the surrounding environment, which is beneficial for heat dissipation. Lasers generate a significant amount of heat during operation; if this heat cannot be dissipated effectively and promptly, it will cause the laser temperature to rise, affecting its performance and lifespan. A larger cathode pad area serves as an excellent heat dissipation interface, rapidly transferring heat from inside the laser to external heat dissipation devices or the environment, reducing the laser's operating temperature, improving heat dissipation efficiency, and thus ensuring stable operation of the laser under prolonged, high-power conditions.

[0058] The cathode pad and substrate are tightly bonded together using conductive adhesive. This adhesive possesses excellent conductivity and adhesion, forming a uniform and continuous conductive layer between the cathode pad and substrate. This ensures smooth current transfer from the cathode pad to the substrate and then to the external circuitry. Simultaneously, the adhesive's bonding effect tightly seals the cathode pad and substrate, reducing gaps, lowering contact resistance, and improving the reliability of the electrical connection. Furthermore, the conductive adhesive exhibits a degree of flexibility, which can buffer stress caused by temperature changes or mechanical vibrations, protecting the cathode pad and substrate from damage and extending the laser's lifespan.

[0059] Connecting the cathode pad to the substrate using a metal weld layer is a more robust and reliable method. The metal weld layer possesses high electrical and thermal conductivity, providing extremely low resistance and an efficient heat conduction path. Through metal welding, an atomic-level bond is formed between the cathode pad and the substrate, resulting in a high connection strength that is less prone to loosening or poor contact, ensuring long-term stability of electrical connection and heat dissipation performance. Simultaneously, the metal weld layer can withstand significant current and temperature variations, making it suitable for high-power, high-requirement laser applications.

[0060] In some embodiments, the polarization grid is made of a metallic material, which is one or more of aluminum, gold, or copper, and the linewidth of the polarization grid is between 50 nm and 100 nm, and the line spacing is between 100 nm and 200 nm.

[0061] Aluminum possesses excellent electrical conductivity, which is crucial for achieving efficient photoelectric modulation of polarization gratings. In lasers, current needs to be transmitted and modulated through polarization gratings. Aluminum's high conductivity reduces current loss during transmission, ensuring stable operation of the polarization grating. Simultaneously, aluminum exhibits certain reflection and absorption characteristics for specific wavelengths of light. By rationally designing the polarization grating structure, these optical properties of aluminum can be utilized to modulate the polarization state of light. Aluminum is a relatively inexpensive metal, and its large-scale use can reduce the manufacturing cost of lasers. Furthermore, aluminum has excellent machinability and is easily processed using semiconductor manufacturing processes such as photolithography and etching. This allows for the fabrication of polarization grating structures with the required linewidth and spacing, meeting the high-precision polarization modulation requirements of lasers.

[0062] Gold possesses extremely high chemical stability, resisting oxidation and corrosion in various environments, ensuring the performance stability of polarization gratings during long-term use. Simultaneously, gold exhibits excellent electrical conductivity, second only to silver, effectively reducing resistance during current transmission, minimizing energy loss, and improving the efficiency of the polarization grating. Gold also demonstrates good light reflectivity, and its high surface smoothness reduces light scattering and loss during propagation, enhancing the polarization modulation accuracy of the polarization grating. In laser applications requiring high beam quality, gold as a polarization grating material can provide superior optical performance.

[0063] Copper possesses excellent electrical and thermal conductivity, second only to silver and gold in conductivity. In polarization grids, copper's high conductivity ensures rapid and stable current transmission, while its good thermal conductivity helps dissipate heat generated during operation, preventing overheating that could affect the grid's performance and lifespan. Copper is a common and abundant metallic material with relatively low cost. Compared to gold, copper can significantly reduce manufacturing costs in large-scale production without compromising the basic performance of polarization grids, making it a cost-effective material choice.

[0064] Using one or more of aluminum, gold, or copper as the material for polarization gratings allows for the combined use of the advantages of different metals. For example, combining gold and aluminum leverages the chemical stability and optical properties of gold with the low cost and processing advantages of aluminum, reducing manufacturing costs while ensuring the performance of the polarization grating; or combining copper and aluminum utilizes the electrical and thermal conductivity of copper with the lightweight characteristics of aluminum to meet the specific requirements of polarization gratings in different application scenarios.

[0065] The linewidth of the polarization grating is between 50 nm and 100 nm, a range that has been precisely designed and optimized. The linewidth directly affects the polarization modulation accuracy of the grating. A finer linewidth allows for more precise modulation of light, enabling more accurate control over the polarization direction and intensity distribution, thus improving the polarization output performance of the laser. This is crucial for applications requiring extremely high polarization purity, such as quantum communication and high-precision optical measurement. The choice of linewidth also considers the feasibility of manufacturing processes and the balance between performance. If the linewidth is too small, the manufacturing difficulty and cost will increase significantly, and errors during manufacturing may lead to unstable performance of the polarization grating. Conversely, if the linewidth is too large, the requirements for polarization modulation accuracy cannot be met. Under current technological conditions, a linewidth range of 50 nm to 100 nm can be achieved through advanced manufacturing processes (such as electron beam lithography and focused ion beam etching) while ensuring that the polarization grating has sufficient polarization modulation capability to meet the practical application requirements of lasers.

[0066] The line spacing, between 100nm and 200nm, significantly influences the propagation and coupling of light within the polarization grating. A suitable line spacing controls diffraction and interference effects within the grating, enabling polarization modulation as desired. If the line spacing is too small, coupling between light beams becomes excessively strong, leading to an uneven light field distribution and affecting the accuracy and stability of polarization modulation. Conversely, if the line spacing is too large, the interaction between light beams weakens, hindering the full utilization of the polarization grating's modulation effect. A line spacing of 100nm-200nm ensures effective polarization modulation while maintaining a uniform light field distribution, improving the laser's polarization output quality. The selection of the line spacing also needs to consider compatibility with other laser components (such as the aperture and resonant cavity). A reasonable line spacing ensures good optical coupling and electrical connection between the polarization grating and other laser components, reducing energy loss and signal interference, and improving the overall performance and reliability of the laser. For example, matching the line spacing to the size and spacing of the aperture allows light emitted from the aperture to interact better with the polarization grating, achieving efficient polarization modulation.

[0067] In some embodiments, the direction of the polarization grating is set at a certain angle to the axis of the light-emitting aperture, and the angle is between 0° and 45°.

[0068] When the angle between the polarization grating direction and the axial direction of the emission aperture is 0°, the polarization grating exhibits a special polarization modulation state. At this time, the grating strips of the polarization grating are parallel to the propagation direction of the light emitted from the emission aperture, selectively transmitting or reflecting light with specific polarization directions. For example, if the polarization grating is designed to allow only polarized light perpendicular to the grating strip direction to pass through, then at a 0° angle, only light with a polarization direction perpendicular to the emission aperture axis can pass through the polarization grating smoothly, while light with other polarization directions will be reflected or absorbed. This achieves initial polarization screening of the light, providing a light source with a specific polarization state for subsequent optical processing or applications. The 0° angle setting makes the relative positional relationship between the polarization grating and the emission aperture simple and direct, which is beneficial for simplifying the overall structural design and manufacturing process of the laser. During assembly, no complex angle adjustments are required, reducing assembly difficulty and cost, and improving production efficiency. At the same time, this simple structure also reduces optical errors that may be introduced due to angular deviations, ensuring the polarization stability of the laser output light.

[0069] When the angle between the polarization grating and the aperture axis is 45°, the polarization grating possesses a unique polarization state conversion capability. The light emitted from the aperture is typically natural light or linearly polarized light with a certain polarization state. When it is incident on the polarization grating at a 45° angle, the grating converts the polarization state of the incident light. For example, light that is originally linearly polarized may decompose into two orthogonally polarized components after passing through the grating at a 45° angle, and the amplitude and phase relationship of these two components will change, thus generating a new polarization state. This polarization state conversion function is crucial in applications requiring specific polarization state output, such as polarization multiplexing technology in optical communication and polarization analysis in optical measurement. The 45° angle setting allows the laser to output light with multiple different polarization states, greatly expanding the application range of lasers. By adjusting the angle between the polarization grating and the aperture axis, the polarization state of the output light can be flexibly controlled to meet the specific polarization requirements of different application scenarios. For example, in the field of optical imaging, light with different polarization states can be used to enhance image contrast and eliminate reflected light interference; in the field of optical processing, light with specific polarization states can improve processing accuracy and quality.

[0070] Within an angle range of 0° to 45°, the polarization control effect of the polarization grating on light exhibits a continuous variation. By adjusting the angle, the polarization state and polarization purity of the output light can be precisely controlled. For example, as the angle gradually increases from 0° to 45°, the polarization filtering and conversion effect of the polarization grating on the light gradually strengthens, and the polarization state of the output light changes accordingly. This flexibility allows lasers to adapt to more complex and diverse application requirements, providing more options for the design and optimization of optical systems.

[0071] Different angle settings affect the performance and manufacturing cost of lasers. A smaller angle may mean relatively weaker polarization control, but a simpler manufacturing process and lower cost; while a larger angle can achieve stronger polarization control, it may increase manufacturing difficulty and cost. Within the angle range of 0° to 45°, an appropriate angle can be selected based on specific application requirements and cost budgets to achieve a balance between performance and cost, thereby improving the laser's market competitiveness.

[0072] A well-designed angle can significantly improve the optical performance of a laser. By precisely controlling the angle between the polarization grating and the axis of the emission aperture, the polarization state of the output light can be optimized, reducing polarization crosstalk and polarization loss, and improving the polarization purity and transmission efficiency. This is crucial for applications with extremely high optical performance requirements, such as quantum optics and high-precision optical measurement.

[0073] A stable angle setting helps enhance the system stability of the laser. When the angle between the polarization grating and the axis of the emission aperture remains constant, the polarization state of the laser output light also remains stable, unaffected by external environmental factors (such as temperature changes, mechanical vibrations, etc.). This stability ensures that the laser can continuously output high-quality polarized light during long-term operation, improving the reliability and stability of the system.

[0074] In some embodiments, the linewidth and spacing of the polarization grids on the surfaces of at least two of the array of light-emitting holes are different.

[0075] In an array of light-emitting apertures, different linewidths and spacings of polarization gratings on the surfaces of different apertures can produce diverse polarization outputs. Linewidth and spacing are key parameters of the polarization grating, directly affecting its ability to modulate the polarization of light. When the linewidth and spacing change, the transmittance and reflectance of the polarization grating for light with different polarization directions also change. For example, a narrower linewidth and smaller spacing may allow the polarization grating to have higher selective transmittance for light with a specific polarization direction, resulting in light with higher polarization purity; while a wider linewidth and larger spacing may produce a wider polarization modulation range, outputting light with different polarization characteristics. By setting different linewidths and spacings in the array of light-emitting apertures, light with multiple polarization states can be obtained simultaneously, meeting the needs of complex optical systems for different polarized light.

[0076] Different combinations of linewidth and spacing can optimize the polarization coupling efficiency between the polarization grating and the light emitted from the aperture. The light emitted from the aperture typically has a specific polarization distribution. By adjusting the linewidth and spacing of the polarization grating, the grating can be better matched to the polarization characteristics of the emitted light, improving the interaction efficiency between the light and the grating. For example, when the light emitted from the aperture has a high intensity in a certain polarization direction, the corresponding polarization grating linewidth and spacing can be set to allow the light in that polarization direction to pass through the grating more effectively, reducing energy loss and improving the overall output efficiency of the laser.

[0077] In optical measurement and imaging, different measurement objects and imaging requirements necessitate light with different polarization states to enhance measurement accuracy and imaging quality. For example, in polarized optical microscopy, light with different polarization states can distinguish different structures and properties of a sample, improving imaging contrast and resolution. By setting diverse polarization grating linewidths and spacings in the array of light-emitting apertures, a variety of polarization states of light sources can be provided to meet the needs of different optical measurement and imaging applications, enabling more comprehensive and accurate analysis and imaging of samples.

[0078] In some embodiments, both the anode pad and the cathode pad are provided with pins for connecting to external circuits. The pins are made of metal and their surfaces are plated with gold or nickel.

[0079] The anode and cathode pads have pins for connecting to external circuits, serving as crucial bridges for energy exchange and information transmission between lasers and other electronic devices. When a laser is operating, the external power supply needs to transmit electrical energy to the anode and cathode through these pins, providing the necessary current for the laser's light emission process. For example, in laser communication systems, the laser requires a stable operating current to emit light signals of specific wavelengths and intensities; the presence of these pins ensures that the power supply can be reliably connected to the laser's anode and cathode, maintaining the laser's normal operation.

[0080] The pin design allows lasers to be easily integrated into various electronic devices and circuit boards. By inserting the pins into corresponding holes on the circuit board or soldering them to pads, lasers can be tightly connected with other electronic components to form a complete electronic system. This integration method not only improves the compactness and reliability of electronic devices but also facilitates mass production and maintenance. For example, in portable electronic devices such as smartphones and tablets, lasers, as important optical components, work in conjunction with other chips and circuits through pins to achieve functions such as proximity sensing and facial recognition.

[0081] Metals possess excellent electrical conductivity, ensuring efficient and stable current transmission through the pins. When a laser operates, a large current is required to drive the light emission process. The low resistance of metal pins reduces energy loss during current transmission, improving energy efficiency. For example, copper is a commonly used metal pin material; its high conductivity meets the high current transmission requirements of lasers, ensuring stable laser output power.

[0082] Metal pins possess a certain degree of mechanical strength, enabling them to withstand certain external forces and vibrations. During the production, transportation, and use of electronic devices, they are inevitably subjected to various mechanical stresses. The high strength of metal pins ensures a secure and reliable connection to the solder pads and circuit boards, preventing loosening or breakage. For example, in industrial automation equipment, lasers may be installed in environments with significant vibration. Metal pins can withstand this vibration, ensuring a stable connection between the laser and external circuits and guaranteeing the normal operation of the equipment.

[0083] Gold is a metal with excellent electrical conductivity. Plating gold on the pin surface can further reduce the pin resistance and improve the current transmission efficiency. Compared with unplated metal pins, gold-plated pins can reduce current scattering and loss on the pin surface, allowing more electrical energy to be effectively transmitted to the anode and cathode of the laser, thereby improving the luminous efficiency and performance of the laser.

[0084] Gold possesses excellent chemical stability and is not easily oxidized or corroded in various environments. During the use of electronic devices, pins may come into contact with moisture, oxygen, and other chemicals in the air. These substances can cause oxidation of the pin surface, affecting its conductivity and connection reliability. Gold plating forms a dense gold layer on the pin surface, effectively preventing external chemicals from contacting the pin substrate, protecting the pin from corrosion, and extending its lifespan.

[0085] Gold has excellent solderability; plating gold on the lead surface improves the wettability between the lead and the solder, making the soldering process easier and more reliable. When soldering lasers onto circuit boards, gold-plated leads can fully fuse with the solder, forming a strong solder joint, reducing soldering defects, and improving the manufacturing quality and reliability of electronic equipment.

[0086] Compared to gold plating, nickel plating is relatively cheaper. Under certain performance requirements, nickel plating can reduce the manufacturing cost of lasers and improve the product's market competitiveness. For cost-sensitive applications, such as the mass production of consumer electronics, nickel-plated leads are an economical choice.

[0087] Nickel itself has a certain degree of corrosion resistance. Plating nickel on the lead surface can form a protective layer, preventing the lead substrate (such as copper) from direct contact with the external environment and slowing down the oxidation and corrosion rate of the substrate. At the same time, the nickel plating layer can also provide a good base for subsequent gold plating or other surface treatments, enhancing the adhesion and stability of the plating.

[0088] Nickel plating offers high hardness and wear resistance, enabling it to withstand a certain degree of friction and abrasion. During the assembly and use of electronic devices, pins may rub against other components or tools. Nickel plating protects the pin surface from damage, ensuring that the pin's conductivity and connection reliability remain unaffected.

[0089] In some embodiments, the number of pins on the anode pad is related to the number of rows or columns of the array of light-emitting holes. When the array of light-emitting holes is m rows and n columns, the number of pins on the anode pad is m+n-1. By connecting different combinations of pins, independent control of different groups and regions of the array of light-emitting holes can be achieved, further optimizing the brightness gradient effect.

[0090] When the array of LEDs is arranged in m rows and n columns, the number of pins on the anode pads is set to m + n - 1. This design is not arbitrary, but based on precise consideration of the flexible control requirements of the LED array. From a circuit connection perspective, this numerical relationship enables efficient signal transmission and control distribution. For example, in a 3x3 array (m = 3, n = 3) LED layout, the number of pins on the anode pads is calculated to be 3 + 3 - 1 = 5. By rationally designing the connection method between these 5 pins and the LEDs, the entire array can be covered, achieving precise control of different LEDs.

[0091] The underlying logic of this quantitative relationship lies in covering all the light-emitting holes through combinations of rows and columns. Assuming rows and columns are used as control dimensions, m row pins can control the common anode of the light-emitting holes in each row, and n column pins can control the common anode of the light-emitting holes in each column. However, to avoid redundant control and simplify circuit design, an approach using m+n-1 pins is employed. Through clever circuit connections, each light-emitting hole can be uniquely selected or selected in combination, thus achieving comprehensive control over the entire array of light-emitting holes.

[0092] By combining different pins, different groups of array light-emitting holes can be easily achieved. For example, in the 3x3 array mentioned above, the five pins can be divided into multiple groups through specific circuit design. For instance, the light-emitting holes in the first row and first column can be grouped together, and by controlling the combination of the corresponding row and column pins, the light-emitting holes in this group can be made to work or be turned off simultaneously. This grouping control method can be flexibly adjusted according to actual needs. For example, several adjacent light-emitting holes can be grouped together to achieve localized brightness adjustment or pattern display.

[0093] In addition to group control, it also enables independent control of different areas of the array's light-emitting holes. The array can be divided into multiple independent areas, each controlled by a specific pin combination. For example, in a large array, a portion of the light-emitting holes in the upper left corner can be designated as area A, and a portion in the upper right corner as area B, with different pin combinations controlling the light-emitting holes in these two areas respectively. In this way, when displaying images or controlling lighting, the brightness, color, and other parameters of each area can be adjusted independently, achieving more precise and diverse control effects.

[0094] By utilizing different pin combinations to control the grouping and regions of the array's light-emitting holes, a foundation is provided for achieving brightness gradient effects. By controlling the number of working holes and the operating current in each group or region, the brightness of that region can be precisely adjusted. For example, in an array composed of multiple groups, gradually increasing or decreasing the number of working holes in each group, or adjusting the operating current of each group, can achieve a smooth brightness gradient from bright to dark or from dark to bright.

[0095] This optimized brightness gradient effect has significant advantages. In display applications, it can achieve more natural and realistic image display, reducing visual discomfort caused by sudden brightness changes.

[0096] The optimized brightness gradient effect also expands the application scenarios for devices such as lasers. In automotive lighting, it enables adaptive brightness adjustment, automatically adjusting the brightness gradient of the LiDAR emission speckle according to different road conditions and ambient light, thereby improving driving safety.

[0097] In some embodiments, an encapsulation layer is also included on the outer side of the upper surface. The encapsulation layer is made of transparent or semi-transparent epoxy resin, silicone, or glass material, and the encapsulation layer completely covers the anode pad, the array of light-emitting holes, and the polarization grid.

[0098] The encapsulation layer is positioned on the outer side of the upper surface, a location chosen with full consideration of the protection requirements for internal components. The upper surface is typically the part of the laser and other devices that are in direct contact with the external environment, and it is also the area most susceptible to external influences. Placing the encapsulation layer on the outer side of the upper surface forms an effective protective barrier, protecting critical components such as the anode pads, array light-emitting apertures, and polarization grids.

[0099] The encapsulation layer completely covers the anode pads, the array of light-emitting apertures, and the polarization grid. This comprehensive coverage ensures that the internal components are protected from direct damage by the external environment. The anode pads, as critical components for electrical connection, need to be protected against oxidation, corrosion, and mechanical damage; the array of light-emitting apertures is the core area for light output, and it is essential to prevent the entry of dust, moisture, and other impurities that could affect light emission performance; the polarization grid plays a crucial role in controlling the polarization of light, and its structural stability and optical performance must be maintained. The complete coverage of the encapsulation layer provides a reliable protective environment for these components.

[0100] The encapsulation layer is made of transparent or semi-transparent epoxy resin, silicone, or glass. These three materials are widely used in optical and electronic packaging, each with its own unique advantages.

[0101] Epoxy resin possesses excellent adhesive properties, electrical insulation properties, and mechanical strength. It can firmly bond internal components to the encapsulation layer, preventing components from loosening or detaching. Simultaneously, the transparent or translucent nature of epoxy resin allows light to pass through smoothly, reducing light absorption and scattering, and improving light output efficiency.

[0102] Silicone possesses excellent flexibility, heat resistance, and weather resistance. During laser operation, a certain amount of heat may be generated; the heat resistance of silicone ensures that the encapsulation layer does not deform or become damaged in high-temperature environments. Its flexibility can also alleviate stress caused by thermal expansion or mechanical vibration, protecting internal components from damage. Furthermore, the translucent nature of silicone also meets the requirements for light transmission.

[0103] Glass possesses extremely high optical transparency and chemical stability. Its transparency ensures virtually no light loss during transmission, providing clear and accurate light output. Simultaneously, its chemical stability allows it to resist corrosion from various chemicals, extending the lifespan of the encapsulation layer.

[0104] These transparent or translucent materials, while ensuring light transmittance, also possess other important properties. For example, they all have excellent electrical insulation properties, preventing electrical short circuits between internal components and the external environment and ensuring the electrical safety of the laser. Furthermore, their chemical stability resists the corrosive effects of moisture, oxygen, and other chemicals in the external environment, protecting internal components from corrosion.

[0105] The most direct function of the encapsulation layer is to protect the internal components. It prevents external dust, moisture, chemicals, and other contaminants from entering the device, avoiding problems such as corrosion, short circuits, or performance degradation caused by these impurities to components like anode pads, array light-emitting holes, and polarization grids. Simultaneously, the encapsulation layer also buffers external mechanical shocks and vibrations, reducing component damage caused by mechanical stress and improving device reliability and lifespan.

[0106] A transparent or semi-transparent encapsulation layer ensures smooth light transmission and output within the device. It does not significantly absorb, scatter, or reflect light, thus maintaining the luminous performance of the array apertures and the polarization control effect of the polarization grating. This is crucial for optical devices such as lasers, ensuring high-quality optical signal output to meet the needs of various optical applications.

[0107] The encapsulation layer holds the internal anode pads, arrayed light-emitting apertures, and polarization grids together, forming a unified structure. This structural stability prevents component displacement or deformation during operation, ensuring the stability of the device's optical and electrical performance. Simultaneously, the encapsulation layer also provides some heat dissipation, transferring heat generated inside the device to the external environment, preventing overheating from affecting the device's performance and lifespan.

[0108] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to implement or use this invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this invention. Therefore, this invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0109] The specific embodiments of this utility model have been described above. It should be understood that this utility model is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the substantive content of this utility model.

Claims

1. A graded-color VCSEL laser, characterized in that, The outer side of the upper surface is an anode pad, the central area is an array of light-emitting holes, and the bottom is a cathode pad; The surface of the light-emitting aperture is covered with a polarization grid. The gain of the Vcsel aperture resonant cavity is modulated by the direction of the polarization grid, thereby achieving a gradual change in brightness.

2. The graded VCSEL laser according to claim 1, characterized in that, The anode pad has a ring structure and is arranged around the array of light-emitting holes. The width of the anode pad is between 0.5mm and 2mm to optimize the current distribution and improve the working stability of the laser.

3. A graded VCSEL laser according to claim 1, characterized in that, The array of light-emitting holes is arranged in a regular rectangular array, with the spacing between adjacent light-emitting holes ranging from 10μm to 50μm.

4. A graded VCSEL laser according to claim 1, characterized in that, The cathode pad has a planar structure with an area larger than that of the anode pad, and the cathode pad is tightly connected to the substrate by conductive adhesive or a metal welding layer to ensure good electrical connection and heat dissipation performance.

5. A graded VCSEL laser according to claim 1, characterized in that, The polarization grid is made of a metallic material, which is one or more of aluminum, gold, or copper. The linewidth of the polarization grid is between 50 nm and 100 nm, and the line spacing is between 100 nm and 200 nm.

6. A graded VCSEL laser according to claim 1, characterized in that, The polarization grating is set at a certain angle to the axis of the light-emitting aperture, and the angle is between 0° and 45°.

7. A graded VCSEL laser according to claim 1, characterized in that, The polarization grids on the surfaces of at least two of the array of light-emitting holes have different linewidths and line spacings.

8. A graded VCSEL laser according to claim 1, characterized in that, Both the anode pad and the cathode pad are provided with pins for connecting to external circuits. The pins are made of metal and their surfaces are plated with gold or nickel.

9. A graded VCSEL laser according to claim 8, characterized in that, The number of pins on the anode pad is related to the number of rows or columns of the array of light-emitting holes. When the array of light-emitting holes is m rows and n columns, the number of pins on the anode pad is m+n-1. By connecting different combinations of pins, independent control of different groups and areas of the array of light-emitting holes can be achieved, further optimizing the brightness gradient effect.

10. A graded VCSEL laser according to claim 1, characterized in that, It also includes an encapsulation layer disposed on the outer side of the upper surface. The encapsulation layer is made of transparent or semi-transparent epoxy resin, silicone or glass material, and the encapsulation layer completely covers the anode pad, the array of light-emitting holes and the polarization grid.

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