Light-emitting device with improved light output and method for producing the same

Abstract

The present disclosure provides a light-emitting device with improved light output and a preparation method thereof, and belongs to the technical field of optoelectronic manufacturing. The light-emitting device comprises a light-emitting functional layer, a driving substrate and a brightening functional layer. The light-emitting functional layer is located on the driving substrate, and comprises a plurality of light-emitting units arranged at intervals. The brightening functional layer comprises a bearing layer, a reflective layer and a plurality of light-emitting lenses. The bearing layer is located on the surface of the light-emitting functional layer away from the driving substrate. The surface of the bearing layer has a plurality of light-emitting grooves exposing the light-emitting functional layer. Each light-emitting groove exposes at least one light-emitting unit. The reflective layer is located on at least the groove wall of each light-emitting groove. The light-emitting grooves correspond to the light-emitting lenses one by one, and the light-emitting lenses are located in the corresponding light-emitting grooves. The embodiments of the present disclosure can improve the problem of low light output of the light-emitting device and improve the brightness of the light-emitting device.

Description

Technical Field

[0001] This disclosure relates to the field of optoelectronic manufacturing technology, and in particular to a light-emitting device with improved light output and a method for its fabrication. Background Technology

[0002] With advancements in Micro LED (Micro Light Emitting Diode) technology, the industry often integrates Micro LED chips with CMOS driving circuits to create an array of luminescent micropixels. This light-emitting device combines the advantages of high resolution, small size, and low power consumption, meeting the requirements of intelligent projection automotive lights, and therefore has a very broad application prospect in the automotive lighting field.

[0003] In related technologies, light-emitting devices typically include a driving substrate and multiple MicroLED chips arranged in an array on it. To improve the overall light output, a light-emitting lens is usually integrated on each MicroLED chip.

[0004] However, Micro LED chips have low photoelectric conversion efficiency. Even with the addition of light-emitting lenses to improve the light path, the brightness of the chips often fails to meet the expected requirements of high-brightness applications such as automotive lights, thus affecting the actual performance. Summary of the Invention

[0005] This disclosure provides a light-emitting device with improved light output and its fabrication method, which can improve the problem of low light output and increase the brightness of the light-emitting device. The technical solution is as follows: On one hand, this disclosure provides a light-emitting device, which includes: a light-emitting functional layer, a driving substrate, and a brightness enhancement functional layer. The light-emitting functional layer is located on the driving substrate and includes a plurality of light-emitting units arranged at intervals. The brightness enhancement functional layer includes: a carrier layer, a reflective layer, and a plurality of light-emitting lenses. The carrier layer is located on the surface of the light-emitting functional layer away from the driving substrate. The surface of the carrier layer has a plurality of light-emitting grooves exposing the light-emitting functional layer. Each light-emitting groove exposes at least one light-emitting unit. The reflective layer is located at least on the groove wall of each light-emitting groove. Each light-emitting groove corresponds to a light-emitting lens, and the light-emitting lens is located in the corresponding light-emitting groove.

[0006] In one implementation of this disclosure, the orthographic projection of the bottom of the light-emitting groove on the surface of the driving substrate is located within the orthographic projection of the opening of the light-emitting groove on the surface of the driving substrate.

[0007] In another implementation of this disclosure, the wall of the light-emitting groove is an inclined surface; or, the wall of the light-emitting groove is a concave curved surface.

[0008] In another implementation of this disclosure, the reflective layer includes at least one of a metal layer and a DBR layer.

[0009] In another implementation of this disclosure, the reflective layer is also located on the surface of the carrier layer away from the driving substrate.

[0010] In another implementation of this disclosure, the sidewall of the light-emitting lens is in contact with the wall of the corresponding light-emitting groove, and the surface of the light-emitting lens away from the driving substrate is a convex arc surface.

[0011] In another implementation of this disclosure, the light-emitting unit has opposite light-emitting surfaces and backlighting surfaces, the light-emitting surfaces being away from the driving substrate; at least a portion of the sidewall of the light-emitting unit is an outwardly convex curved surface, the light-emitting unit includes a first semiconductor layer, a multi-quantum well layer and a second semiconductor layer stacked sequentially, the surface of the first semiconductor layer away from the second semiconductor layer is the backlighting surface, and the outwardly convex curved surface is located at least on the sidewall where the multi-quantum well layer is located.

[0012] In another implementation of this disclosure, the backlight surface of each of the light-emitting units has an annular groove that exposes the second semiconductor layer, and the annular groove surrounds the light-emitting unit around its periphery, with the groove wall of the annular groove serving as the sidewall of each of the light-emitting units.

[0013] In another implementation of this disclosure, the surface of the light-emitting unit away from the driving substrate is a roughened surface, and the brightening functional layer is located on the roughened surface.

[0014] Secondly, embodiments of this disclosure provide a method for fabricating a light-emitting device. The method includes: fabricating a light-emitting functional layer, the light-emitting functional layer including a plurality of spaced-apart light-emitting units; bonding the light-emitting functional layer to a driving substrate; forming a brightness enhancement functional layer on the light-emitting functional layer, the brightness enhancement functional layer including: a carrier layer, a reflective layer and a plurality of light-emitting lenses, the carrier layer being located on the surface of the light-emitting functional layer away from the driving substrate, the surface of the carrier layer having a plurality of light-emitting grooves exposing the light-emitting functional layer, each light-emitting groove exposing at least one light-emitting unit, the reflective layer being located at least on the groove wall of each light-emitting groove, the light-emitting groove corresponding one-to-one with the light-emitting lens, and the light-emitting lens being located within the corresponding light-emitting groove.

[0015] The beneficial effects of the technical solutions provided in this disclosure include at least the following: The light-emitting device provided in this embodiment has a reflective layer disposed within the light-emitting groove of the carrier layer, covering the groove wall and the area surrounding the lens. When the light emitted by the light-emitting unit is collimated by the lens, some of the light that originally escaped laterally from the groove wall due to angular deviation or scattering is efficiently reflected back to the forward light-emitting path by the reflective layer. This process reduces the ineffective dissipation of light through specular reflection, which is equivalent to redirecting the laterally emitted light back into the target illumination area, directly increasing the light flux per unit area.

[0016] Furthermore, in related technologies, the gaps between the light-emitting lenses easily lead to light divergence, forming wide-angle stray light and reducing contrast. The reflective layer, by constraining the light propagation path within the slot, converts laterally scattered light into forward effective light, making the emitted beam more concentrated and significantly narrowing the emission angle. This characteristic enhances the central brightness of the illuminated area and reduces interference light in other directions, improving visual clarity and safety for nighttime driving. Therefore, the light-emitting structure disclosed in this invention achieves the dual function of light recovery and light focusing through the reflective layer, breaking through the brightness bottleneck of Micro LEDs without increasing chip power. Simultaneously, it optimizes optical performance through angle control, effectively improving the brightness and contrast of the light-emitting device. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a light-emitting device provided in an embodiment of this disclosure; Figure 2 This is a schematic diagram of a brightness enhancement function layer provided in an embodiment of this disclosure; Figure 3 This is a schematic diagram of another brightness enhancement function layer provided in an embodiment of this disclosure; Figure 4 This is a partial schematic diagram of a light-emitting device provided in an embodiment of this disclosure; Figure 5 This is a schematic diagram of the structure of a light-emitting unit provided in an embodiment of this disclosure; Figure 6 This is a flowchart of a method for fabricating a light-emitting device according to an embodiment of this disclosure; Figure 7 This is a fabrication state diagram of a light-emitting device provided in an embodiment of this disclosure; Figure 8 This is a fabrication state diagram of a light-emitting device provided in an embodiment of this disclosure.

[0019] The markings in the diagram are explained as follows: 10. Light-emitting functional layer; 100. Light-emitting unit; 101. Annular groove; 11. First semiconductor layer; 12. Multiple quantum well layer; 13. Second semiconductor layer; 20. Driving substrate; 21. Electrode block; 30. Brightness enhancement layer; 31. Supporting layer; 310. Light exit groove; 32. Reflective layer; 33. Light exit lens; 40. Insulating reflective layer; 51. First electrode; 52. Second electrode; 60. Passivation layer; 70. Bonded metal block; 80. Filling layer; 90. Substrate. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0021] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” “third,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the elements or objects preceding “comprising” or “including” encompass the elements or objects listed following “comprising” or “including” and their equivalents, and do not exclude other elements or objects. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” “right,” “top,” and “bottom,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0022] Figure 1 This is a schematic diagram of the structure of a light-emitting device provided in an embodiment of this disclosure. Figure 1 As shown, the light-emitting device includes: a light-emitting functional layer 10, a driving substrate 20, and a brightness enhancement functional layer 30. The light-emitting functional layer 10 is located on the driving substrate 20 and includes a plurality of light-emitting units 100 arranged at intervals.

[0023] Figure 2This is a schematic diagram of a brightness enhancement layer 30 provided in an embodiment of this disclosure. Figure 2 As shown, the brightening functional layer 30 includes: a carrier layer 31, a reflective layer 32, and a plurality of light-emitting lenses 33. The carrier layer 31 is located on the surface of the light-emitting functional layer 10 away from the driving substrate 20. The surface of the carrier layer 31 has a plurality of light-emitting grooves 310 that expose the light-emitting functional layer 10. Each light-emitting groove 310 exposes at least one light-emitting unit 100. The reflective layer 32 is located at least on the groove wall of each light-emitting groove 310. The light-emitting groove 310 and the light-emitting lens 33 correspond one-to-one, and the light-emitting lens 33 is located in the corresponding light-emitting groove 310.

[0024] The light-emitting device provided in this embodiment has a reflective layer 32 disposed within the light-emitting groove 310 of the carrier layer 31, covering the groove wall of the light-emitting groove 310 and the area surrounding the lens. When the light emitted by the light-emitting unit 100 is collimated by the lens, some of the light that originally escaped laterally from the groove wall due to angular deviation or scattering is efficiently reflected back to the forward light-emitting path by the reflective layer 32. This process reduces the ineffective dissipation of light through specular reflection, which is equivalent to redirecting the laterally emitted light back into the target illumination area, directly increasing the light flux per unit area.

[0025] Furthermore, in related technologies, the gaps between the light-emitting lenses 33 easily lead to light divergence, forming wide-angle stray light and reducing contrast. The reflective layer 32, by constraining the light propagation path within the slot, converts laterally scattered light into forward effective light, making the emitted beam more concentrated and significantly narrowing the emission angle. This characteristic enhances the central brightness of the illuminated area and reduces interference light in other directions, improving visual clarity and safety for nighttime driving. Therefore, the light-emitting structure of this disclosure achieves the dual function of light recovery and light focusing through the reflective layer 32, breaking through the brightness bottleneck of Micro LED without increasing chip power. Simultaneously, it optimizes optical performance through angle control, effectively improving the brightness and contrast of the light-emitting device.

[0026] Optionally, such as Figure 2 As shown, the orthographic projection of the bottom of the light-emitting groove 310 onto the surface of the driving substrate 20 is located within the orthographic projection of the opening of the light-emitting groove 310 onto the surface of the driving substrate 20.

[0027] The orthographic projection of the bottom of the light-emitting slot 310 onto the surface of the driving substrate 20 lies within the orthographic projection of the opening, indicating that the light-emitting slot 310 has a converging structure that is wider at the top and narrower at the bottom (such as an inverted trapezoidal or conical cross-section). This converging slot wall makes it easier for the side-scattered light emitted by the light-emitting unit 100 to be captured by the reflective layer 32. When the light encounters the inclined slot wall, the reflection angle decreases, and more light is guided to the positive light-emitting path instead of escaping outside the slot. Compared with a vertical slot wall, the converging structure extends the reflection path of light within the slot, and together with the high-reflectivity layer 32, it achieves secondary light focusing, further improving the brightness and concentration of the emitted light, which is especially beneficial for scenarios requiring high center illumination, such as automotive headlights.

[0028] Furthermore, the convergent groove shape makes it easy to control the projection tolerance during the etching of the support layer 31, and the positional relationship between the bottom of the groove and the opening is clear, which can reduce the processing difficulty; and the light-emitting lens 33 is more stable due to the constraint of the groove wall, reducing the risk of displacement caused by thermal expansion or vibration, and ensuring long-term consistent light efficiency.

[0029] In one implementation of this disclosure, such as Figure 2 As shown, the wall of the light-emitting slot 310 is an inclined surface.

[0030] The tilted surface, with its fixed tilt angle design, reflects the lateral scattered light emitted by the light-emitting unit 100 to the forward light path at a preset angle. This ensures precise convergence into the lens collimation area, reducing the number of ineffective reflections within the slot and improving light recovery efficiency. Compared to a vertical slot wall, the tilted surface shortens the lateral light escape distance, and in conjunction with the reflective layer 32, achieves focused light with a single reflection, making it particularly suitable for scenarios requiring high optical path precision, such as automotive headlights.

[0031] In another implementation of this disclosure, Figure 3 This is a schematic diagram of another brightness enhancement layer 30 provided in an embodiment of this disclosure. For example... Figure 3 As shown, the wall of the light-emitting groove 310 is a concave curved surface.

[0032] Unlike planar inclined groove walls (fixed tilt angle, single reflection direction), the normal direction of each point on a concave curved surface (such as a sphere or cylinder) changes continuously with the curvature. When light emitted by the light-emitting unit 100 is incident on the curved surface at different angles, the tilt of the curved surface at different positions automatically matches the incident angle, so that the reflection path is dynamically adjusted with the incident light angle, just like using mirrors of different curvatures to deal with light coming from different directions, rather than the single-direction reflection of a plane mirror.

[0033] The curved surface allows some light rays to be reflected and then converged and collimated into parallel light by the light-emitting lens 33. This concentrates the dispersed small-angle light into high-intensity forward light, improving the center brightness. Furthermore, when light is incident on the edge of the curved surface, the large curvature of the surface reduces its reflection angle, reflecting the large-angle light that would otherwise escape back into the slot, and then converging into the forward light-emitting path through multiple reflections (or direct guidance).

[0034] For example, the wall of the light-emitting groove 310 is a concave spherical surface.

[0035] The advantage of a concave spherical surface lies in its symmetrical light focusing and omnidirectional light collection capabilities. A sphere possesses rotational symmetry and a unique center of curvature, enabling it to reflect scattered light (especially obliquely incident light) emitted from the light-emitting unit 100 at any angle, guiding it towards a positive light path.

[0036] For example, the wall of the light-emitting groove 310 is a concave cylindrical surface.

[0037] A cylindrical concave surface has curvature in only one dimension. Compared to a sphere, a cylindrical surface is simpler to process and can be formed by roll forming or molding, reducing the difficulty of etching the bearing layer 31.

[0038] Optionally, such as Figure 2 , 3 As shown, the sidewall of the light-emitting lens 33 is in contact with the wall of the corresponding light-emitting groove 310, and the surface of the light-emitting lens 33 away from the driving substrate 20 is a convex arc surface.

[0039] The sidewall of the light-emitting lens 33 fits tightly against the wall of the light-emitting slot 310, eliminating the gap between the light-emitting lens 33 and the slot. This avoids displacement of the light-emitting lens 33 due to thermal expansion or vibration, and also blocks the path of lateral stray light leaking out of the slot. At this time, the reflective layer 32 of the slot wall can completely cover the outer sidewall of the lens, drawing back the scattered light that might have escaped from the edge of the light-emitting lens 33 into the slot. This forms a closed loop with the light recovery effect of the reflective layer 32, further improving the light utilization rate.

[0040] Furthermore, the surface of the light-emitting lens 33 furthest from the driving substrate 20 adopts a convex arc surface. Utilizing the converging effect of its curvature, the light emitted by the light-emitting unit 100 is further compressed to a smaller emission angle, improving center brightness. Compared to a planar light-emitting surface, the convex arc surface allows the emitted light to have a narrow beam with high illuminance, reducing edge light intensity attenuation and improving road illumination brightness. Simultaneously, the sidewall fitting design reduces the difficulty of aligning the light-emitting lens 33 with the light-emitting slot 310.

[0041] Optionally, such as Figure 2 , 3 As shown, the reflective layer 32 is also located on the surface of the carrier layer 31 that is away from the driving substrate 20.

[0042] In addition to emitting light through the light-emitting slot 310, some light from the light-emitting unit 100 will be scattered upwards to the top surface of the carrier layer 31. If there is no reflective layer 32 on the top surface, this part of the light will be easily absorbed by the material of the carrier layer 31 or dissipate to the outside of the light-emitting device; after covering with the reflective layer 32, the scattered light can be efficiently reflected back into the slot or near the light-emitting unit 100, and after being recovered twice by the reflective layer 32 on the slot wall of the light-emitting slot 310, it will flow into the light-emitting path to prevent light leakage.

[0043] Furthermore, the reflective layer 32 on the top surface and the wall of the tank can be prepared by vapor deposition or coating in one step, which can reduce the processing complexity; at the same time, the reflective layer 32 covering the top surface can isolate the environmental moisture and dust from eroding the carrier layer 31 and extend the life of the light-emitting device.

[0044] Optionally, the reflective layer 32 includes at least one of a metal layer and a DBR layer.

[0045] In the example selection, when the reflective layer 32 is a metal layer, the metal layer includes at least one of Ag and Al layers. Ag has a reflectivity of over 98% in the visible light band, which can efficiently recover side-scattered light; Al has a reflectivity of approximately 92% to 95%, is less expensive, and its stability can be further improved through alloying. Both can be rapidly deposited on the tank wall of the light-emitting tank 310 using mature processes such as evaporation and sputtering, and have good adhesion to the support layer 31.

[0046] For example, in automotive lighting scenarios, the Al layer is more suitable for complex operating conditions due to its strong temperature resistance and anti-sulfurization ability; while the Ag layer can maximize light recovery efficiency in high-brightness devices.

[0047] The DBR layer is composed of alternating layers of high and low refractive index media, achieving a performance breakthrough through wavelength-selective high reflectivity.

[0048] For example, the DBR layer includes multiple alternating layers of silicon oxide and multiple layers of titanium oxide. DBR is an inorganic dielectric structure that is resistant to high temperatures and aging, and exhibits extremely low long-term light decay, making it suitable for automotive lighting applications.

[0049] Figure 4 This is a partial schematic diagram of a light-emitting device provided in an embodiment of this disclosure. Figure 4 The diagram illustrates the structure of a single light-emitting unit 100. Figure 4 As shown, at least a portion of the sidewall of the light-emitting unit 100 is a convex curved surface. At least a portion of the sidewall of each light-emitting unit 100 is designed as a convex curved surface. The essence of a convex curved surface is a continuous arc-shaped reflective surface, whose normal direction dynamically changes with the curvature of the surface. When light reaches the sidewall of the light-emitting structure, its propagation direction is adjusted through reflection by the curved surface. The curved surface can directionally deflect most photons that tend to escape from the sides, causing their propagation path to converge towards the light-emitting surface, rather than scattering randomly outwards from the chip.

[0050] For example, the convex surface can be a sphere.

[0051] Spherical surfaces can be easily achieved through photolithography or etching processes, and the gaps between spherical units are easier to control when the array is arranged, ensuring that the reflected light from each light-emitting unit 100 contributes independently to the overall brightness.

[0052] For example, the convex surface can be a parabola.

[0053] When the side light of the light-emitting unit 100 is incident on the parabolic surface at different angles, the reflected light will be concentrated along the axis of the parabolic surface, making it easier to orient the scattered light back to the light surface and greatly improve the effective utilization rate of light.

[0054] For example, the convex surface can be an ellipsoid.

[0055] For example, the convex surface can be a cylindrical arc. A cylindrical arc can be achieved simply by unidirectional etching on the planar sidewalls, which greatly reduces the complexity of the process and makes it suitable for mass production.

[0056] Figure 5 This is a schematic diagram of the structure of a light-emitting unit 100 provided in an embodiment of this disclosure. For example... Figure 5 As shown, the light-emitting unit 100 has opposite light-emitting surfaces and backlighting surfaces, with the light-emitting surface being away from the driving substrate 20.

[0057] like Figure 1 As shown, the orthographic projection of the backlight surface on the driving substrate 20 lies within the orthographic projection of the light-emitting surface on the driving substrate 20.

[0058] The area of ​​the light-emitting surface of the light-emitting unit 100 is larger than that of the backlight surface, forming a cross-sectional shape similar to an inverted trapezoid. This increases the effective light-emitting aperture and directs light to the light-emitting surface. In the inverted trapezoidal structure, the light-emitting surface is farther from the substrate and has a larger lateral dimension, which is equivalent to extending the window of the light-emitting unit 100 from the backlight side towards the light-emitting surface. This flared design directly increases the effective area of ​​light emission, thereby improving the overall brightness.

[0059] Optionally, such as Figure 1 , 5 As shown, the light-emitting unit 100 includes a first semiconductor layer 11, a multi-quantum well layer 12, and a second semiconductor layer 13 stacked sequentially.

[0060] In this embodiment of the present disclosure, one of the first semiconductor layer 11 and the second semiconductor layer 13 is a p-type layer, and the other of the first semiconductor layer 11 and the second semiconductor layer 13 is an n-type layer.

[0061] Optionally, the thickness of the n-type GaN layer can be from 0.5 μm to 1 μm.

[0062] Optionally, the multiple quantum well layer 12 includes alternating InGaN quantum well layers and GaN quantum barrier layers. Specifically, the multiple quantum well layer 12 may include 3 to 8 alternating stacked InGaN quantum well layers and GaN quantum barrier layers.

[0063] As an example, in an embodiment of this disclosure, the multi-quantum-well layer 12 includes five alternating stacked InGaN quantum-well layers and GaN quantum-barrier layers.

[0064] Optionally, the thickness of the multiple quantum well layer 12 can be from 150 nm to 200 nm.

[0065] Optionally, the thickness of the p-type GaN layer can be from 0.5 μm to 1 μm.

[0066] In this embodiment of the disclosure, the surface of the first semiconductor layer 11 that is away from the second semiconductor layer 13 is a backlight surface, and the convex curved surface is located at least on the sidewall where the multi-quantum well layer 12 is located.

[0067] For example, such as Figure 5 As shown, the convex curved surface is located on the sidewall where the first semiconductor layer 11 is located, the sidewall where the multi-quantum well layer 12 is located, and part of the sidewall where the second semiconductor layer 13 is located.

[0068] The multiple quantum well layer 12 is the core region for carrier recombination luminescence in the light-emitting unit 100. When light radiates from the multiple quantum well layer 12 in all directions, most of the light first reaches the sidewall where the multiple quantum well layer 12 is located. If the sidewall of this region is a vertical or non-curved structure, the newly generated side light will be confined inside the unit due to the large incident angle, and will be converted into heat energy or absorbed.

[0069] The convex curved surface is set on the sidewall where the multi-quantum well layer 12 is located. The curved surface reconstructs the optical path through curvature, reflecting the side light that has just been generated and has not yet undergone multiple reflections to the direction of the light-emitting surface, so as to avoid it being repeatedly lost by the multi-layer structure in subsequent propagation, thereby improving the light recovery efficiency.

[0070] Optionally, such as Figure 5 As shown, each light-emitting unit 100 has an annular groove 101 on its back surface that exposes the second semiconductor layer 13, and the annular groove 101 surrounds the light-emitting unit 100 around its peripheral edge, with the groove wall of the annular groove 101 serving as the sidewall of each light-emitting unit 100.

[0071] The annular groove 101 surrounds the light-emitting unit 100, which is equivalent to carving a physical isolation band around the light-emitting unit 100, separating each light-emitting unit 100 from other light-emitting units 100. In this way, the closed structure of the annular groove 101 makes the side wall of the light-emitting structure form a continuous reflection ring, avoiding light leakage to adjacent light-emitting units 100, ensuring that the side light is reflected only through its own groove wall, and improving the directionality of light guidance.

[0072] Furthermore, the annular groove 101 on the backlight surface removes some material, reducing the absorption of light by the backlight surface. This allows light that might have been absorbed by the back of the first semiconductor layer 11 to be reflected to the light-emitting surface through the groove wall of the annular groove 101. At the same time, the reflected light from the groove wall of the annular groove 101 will not dissipate towards the driving substrate 20, but will instead participate in effective light emission.

[0073] Optionally, such as Figure 1 As shown, the light-emitting device also includes an insulating reflective layer 40, which is located at least within the annular groove 101 and on the back surface of the light-emitting unit 100.

[0074] For example, the insulating reflective layer 40 may be a DBR layer.

[0075] In this embodiment, the convex curved surface optimizes the optical path through geometric shape, but the reflection of the curved surface itself still depends on the semiconductor material interface, and some light is still absorbed when reflected by the curved surface. However, by setting a DBR layer as a reflector, the reflectivity of the sidewall of the light-emitting unit 100 can be significantly improved, so that almost all the light guided to the sidewall by the convex curved surface is reflected to the light-emitting surface, thereby improving the side light recovery efficiency.

[0076] Furthermore, the annular groove 101 extends through the first semiconductor layer 11, the multi-quantum well layer 12, and the second semiconductor layer 13. If there is an exposed conductive layer within the annular groove 101, it may cause a short circuit between adjacent light-emitting units 100. The insulating reflective layer 40 can fill the gaps within the groove, isolate regions with different potentials, and avoid the risk of leakage caused by rough groove walls or processing defects.

[0077] Optionally, such as Figure 1 As shown, the insulating reflective layer 40 has through holes that expose the bottom of the annular groove 101 and the backlight surface.

[0078] like Figure 1 As shown, the light-emitting device also includes a first electrode 51 and a second electrode 52. Both the first electrode 51 and the second electrode 52 are located on the surface of the insulating reflective layer 40 away from the light-emitting unit 100. The first electrode 51 is connected to the first semiconductor layer 11 through a via. The second electrode 52 is also located in the annular groove 101 and is connected to the second semiconductor layer 13 through a via.

[0079] Vias serve as vertical conductive channels, directly connecting the electrodes to the semiconductor layer and forming a short-path conduction. The length of the vertical via is only 40 mm thick in the insulating reflective layer, much shorter than that of the lateral wiring, reducing resistance and allowing charge carriers to be injected more efficiently into the multi-quantum-well layer 12, thus improving the uniformity of luminescence intensity.

[0080] Furthermore, the first electrode 51 and the second electrode 52 are both located on the surface of the insulating reflective layer 40 away from the light-emitting unit 100, and are connected to the semiconductor layer through vias to transfer the electrodes from the light-emitting area to the non-light-emitting area, thereby avoiding blocking the light path.

[0081] Meanwhile, the annular groove 101, originally used to define the boundary of the light-emitting unit 100, support the convex curved surface and the insulating reflective layer 40, integrates the second electrode 52 into the annular groove 101, eliminating the need to open up an electrode wiring area on the backlight surface, thus adapting to the high-resolution light pattern requirements of vehicle lights.

[0082] For example, both the first electrode 51 and the second electrode 52 may include at least one of the following: an Al layer, a Cu layer, an Ag layer, and an Au layer.

[0083] Optionally, such as Figure 1As shown, the light-emitting device also includes a transparent conductive layer, which is located on the surface of the first semiconductor layer 11. An insulating reflective layer 40 is also located on the surface of the transparent conductive layer, and the vias of the insulating reflective layer 40 expose the transparent conductive layer. The first electrode 51 is connected to the transparent conductive layer through the vias.

[0084] For example, the transparent conductive layer may be an ITO layer or an IZO layer.

[0085] As an example, the thickness of the transparent conductive layer can be greater than or equal to 2000 angstroms. This thickness range ensures good conductivity for effective transmission of electrical signals while also providing high transparency to reduce obstruction of the light emitted by the light-emitting unit 100.

[0086] Optionally, such as Figure 1 As shown, the light-emitting device also includes a passivation layer 60, a bonding metal block 70, and a leveling layer 80. The passivation layer 60 is located on the surface of the insulating reflective layer 40, on the first electrode 51, and on the second electrode 52. The passivation layer 60 has a through hole exposing the first electrode 51.

[0087] The insulating reflective layer 40 is composed of multiple layers of dielectric films, which are susceptible to corrosion from water vapor and oxygen in the environment, leading to a decrease in reflectivity. The first electrode 51 and the second electrode 52 are prone to oxidation and sulfidation due to long-term exposure. The passivation layer 60 acts as a physical barrier to isolate external corrosion, prevent the reflectivity of the insulating reflective layer 40 from decreasing and the electrode contact resistance from increasing, and extend the device life.

[0088] For example, the passivation layer 60 may be at least one of a silicon oxide layer, a silicon nitride layer, and a titanium oxide layer.

[0089] like Figure 1 As shown, the bonding metal block 70 corresponds one-to-one with the light-emitting unit 100. The bonding metal block 70 is located on the surface of the passivation layer 60 away from the light-emitting unit 100, and is connected to the first electrode 51 of the corresponding light-emitting unit 100 through a through hole.

[0090] Each light-emitting unit 100 is connected to the driving substrate 20 via a dedicated bonding metal block 70, enabling one-to-one current injection, which improves the uniformity of carrier distribution and avoids local overheating and uneven light emission. The bonding metal block 70 is located on the surface of the passivation layer 60 away from the light-emitting unit 100, maintaining a safe distance from the light-emitting surface, and is vertically connected to the electrode through a through-hole to avoid the light emission path.

[0091] For example, the bonding metal block 70 may include at least one of AuBe layer, Au layer, Ti layer, Ni layer and Pt layer.

[0092] like Figure 1As shown, the filler layer 80 is located on the surface of the passivation layer 60 away from the light-emitting unit 100, inside the annular groove 101, and on the sidewall of the bonding metal block 70. The thickness of the filler layer 80 is greater than or equal to the groove depth of the annular groove 101.

[0093] The difference in depth between the annular groove 101 and the height of the bonding metal block 70 can cause an uneven surface, making direct bonding prone to poor soldering. The leveling layer 80 fills the annular groove 101 and covers the sidewalls of the bonding metal block 70, controlling the surface flatness within ±0.5μm, ensuring the coplanarity of the bonding metal block 70 and the driving substrate 20, improving bonding strength, and preventing detachment caused by vibration or thermal expansion and contraction.

[0094] The filling layer 80 can fill the annular groove 101, wrapping the convex curved sidewall of the groove 101 with the sidewall of the bonding metal block 70, enhancing the mechanical strength of the groove, while isolating the internal and external environments of the groove and avoiding electrochemical corrosion.

[0095] Optionally, such as Figure 1 As shown, the surface of the light-emitting unit 100 furthest from the driving substrate 20 is a roughened surface, and the brightening functional layer 30 is located on the roughened surface. The light-emitting surface of the light-emitting unit 100 is set as a roughened surface. The total internal reflection condition of the smooth interface is destroyed by the micro-uneven structure, so that more light is emitted from the light-emitting layer, improving the light extraction efficiency; at the same time, the diffuse reflection effect makes the light emission more uniform, avoiding strong light spots and glare, and adapting to the light distribution requirements of automotive lights.

[0096] Optionally, such as Figure 1 As shown, the driving substrate 20 can be a complementary metal-oxide-semiconductor (CMOS) integrated circuit board.

[0097] like Figure 1 As shown, electrode blocks 21 corresponding to bonding metal blocks 70 are provided on the driving substrate 20. The bonding metal blocks 70 of each light-emitting diode are electrically connected to the corresponding electrode blocks 21 so as to realize the purpose of the driving substrate 20 controlling the operation of each light-emitting diode.

[0098] For example, electrode block 21 may include at least one of AuBe layer, Au layer, Ti layer, Ni layer and Pt layer.

[0099] Figure 6 This is a flowchart illustrating a method for fabricating a light-emitting device according to an embodiment of this disclosure. For example... Figure 6 As shown, the preparation method includes: Step S11: Prepare the luminescent functional layer 10.

[0100] The light-emitting functional layer 10 includes a plurality of light-emitting units 100 arranged at intervals.

[0101] Step S12: Bond the light-emitting functional layer 10 to the driving substrate 20.

[0102] Step S13: Form a brightening functional layer 30 on the light-emitting functional layer 10.

[0103] The brightening functional layer 30 includes a carrier layer 31, a reflective layer 32, and a plurality of light-emitting lenses 33. The carrier layer 31 is located on the surface of the light-emitting functional layer 10 away from the driving substrate 20. The surface of the carrier layer 31 has a plurality of light-emitting grooves 310 that expose the light-emitting functional layer 10. Each light-emitting groove 310 exposes at least one light-emitting unit 100. The reflective layer 32 is located on the groove wall of each light-emitting groove 310. The light-emitting groove 310 and the light-emitting lens 33 correspond one-to-one. The light-emitting lens 33 is located in the corresponding light-emitting groove 310.

[0104] The light-emitting device fabricated by this method has a reflective layer 32 disposed within the light-emitting groove 310 of the carrier layer 31, covering the groove wall of the light-emitting groove 310 and the area surrounding the lens. When the light emitted by the light-emitting unit 100 is collimated by the lens, some of the light that originally escaped laterally from the groove wall due to angular deviation or scattering is efficiently reflected back to the forward light-emitting path by the reflective layer 32. This process reduces the ineffective dissipation of light through specular reflection, which is equivalent to redirecting the laterally emitted light back into the target illumination area, directly increasing the light flux per unit area.

[0105] Step S11 may include the following steps: The first step is to form a light-emitting functional layer on the substrate.

[0106] For example, the substrate is a sapphire substrate. Sapphire substrates have high light transmittance, meaning they are transparent. Furthermore, sapphire material is relatively hard and chemically stable, giving the light-emitting diode (LED) good luminous efficacy and stability.

[0107] The light-emitting functional layer 10 may include a second semiconductor layer 13, a multiple quantum well layer 12 and a first semiconductor layer 11, which are sequentially stacked on the substrate 90.

[0108] The first semiconductor layer 11 has a first conductivity type, the second semiconductor layer 13 has a second conductivity type different from the first conductivity type, and the multi-quantum well layer 12 is used to generate light through electron-hole recombination.

[0109] Among them, one of the first semiconductor layer 11 and the second semiconductor layer 13 is a p-type layer, and the other of the first semiconductor layer 11 and the second semiconductor layer 13 is an n-type layer.

[0110] Optionally, the thickness of the n-type GaN layer can be from 0.5 μm to 1 μm.

[0111] Optionally, the multiple quantum well layer 12 includes alternating InGaN quantum well layers and GaN quantum barrier layers. Specifically, the multiple quantum well layer 12 may include 3 to 8 alternating stacked InGaN quantum well layers and GaN quantum barrier layers.

[0112] As an example, in an embodiment of this disclosure, the multi-quantum-well layer 12 includes five alternating stacked InGaN quantum-well layers and GaN quantum-barrier layers.

[0113] Optionally, the thickness of the multiple quantum well layer 12 can be from 150 nm to 200 nm.

[0114] Optionally, the thickness of the p-type GaN layer can be from 0.5 μm to 1 μm.

[0115] The second step is to continue growing a transparent conductive layer on the surface of the light-emitting functional layer 10.

[0116] For example, the transparent conductive layer may be an ITO layer or an IZO layer.

[0117] The third step is to form an isolation groove on the surface of the light-emitting functional layer 10 to divide the light-emitting functional layer 10 into multiple light-emitting units 100.

[0118] The distance from the bottom of the isolation trench to the substrate 90 is 200nm to 300nm.

[0119] After the light-emitting functional layer 10 is formed on the substrate 90, the surface is etched only to create an isolation trench 200 nm to 300 nm from the bottom of the trench to the substrate 90. At this point, the trench does not penetrate the light-emitting functional layer 10. This serves to temporarily define the cell boundaries. In subsequent processes such as bonding to the driving substrate 20 and removing the substrate 90, which are prone to material deformation, the shallow trench can prevent the epitaxial layers of adjacent light-emitting cells 100 from sticking together or becoming mixed due to stress, thus maintaining cell independence. If the trench were etched through the layer from the beginning, the thin light-emitting functional layer 10 would easily collapse during transfer, leading to blurred boundaries and uncontrolled cell dimensions.

[0120] The fourth step is to deposit an insulating reflective layer 40 to cover the light-emitting functional layer 10 and the walls and bottom of the isolation tank.

[0121] The isolation grooves are crisscrossed to separate multiple light-emitting units 100. For each light-emitting unit 100, the isolation groove is also an annular groove 101 that surrounds the light-emitting unit 100.

[0122] The fifth step involves etching the insulating reflective layer 40 to form vias, exposing the bottom of the isolation trench and the first semiconductor layer 11.

[0123] The sixth step is to prepare a first electrode 51 at the via and connect it to the first semiconductor layer 11.

[0124] Step 7: A second electrode 52 is fabricated at the via in the annular groove 101 and connected to the second semiconductor layer 13.

[0125] Step 8: Deposit a passivation layer 60 to cover the electrode and the insulating reflective layer 40, leaving an electrode connection via.

[0126] Step 9, as Figure 7 As shown, a bonding metal block 70 is formed on the passivation layer 60 and connected to the first electrode 51 through a through hole. The bonding metal block 70 corresponds one-to-one with the first electrode 51 of the light-emitting unit 100.

[0127] Step 10, as follows Figure 7 As shown, the deposited fill layer 80 covers the passivation layer 60, the isolation groove, and the sidewall of the bonded metal block 70.

[0128] Step S12 may include the following steps: The first step is to bond each light-emitting unit 100 to the driving substrate 20 and remove the substrate 90.

[0129] Specifically, this includes: such as Figure 7 As shown, an electrode block 21 is formed on the surface of the driving substrate 20, and the electrode block 21 is bonded together with the bonding metal block 70.

[0130] For example, electrode block 21 may include at least one of AuBe layer, Au layer, Ti layer, Ni layer and Pt layer.

[0131] The second step, as Figure 8 As shown, the light-emitting functional layer 10 region where the isolation trench is located is etched until the light-emitting functional layer 10 is penetrated to form multiple light-emitting units 100 arranged at intervals.

[0132] Specifically, this may include: directional etching of the residual light-emitting functional layer 10 in the area where the isolation trench is located, controlling the depth to penetrate the light-emitting functional layer 10, precisely removing 200nm to 300nm of material from the bottom of the trench, so that adjacent light-emitting units 100 are completely physically separated, forming a clearly defined spaced array, and avoiding damage to the core multi-quantum well layer 12 of the unit.

[0133] After bonding and removing the substrate 90, the isolation trench area is etched a second time until it penetrates the light-emitting functional layer 10. At this time, the epitaxial layer remaining at the bottom of the trench is removed, so that adjacent cells are completely physically separated. Since the light-emitting functional layer 10 is fixed to the driving substrate 20, the depth and width can be precisely controlled during etching to ensure that the isolation trench only removes the crosstalk risk area without damaging the light-emitting unit 100; and it also blocks the light propagation across the light-emitting unit 100, reducing crosstalk from the source.

[0134] Step S13 may include the following steps: The first step is to prepare a transparent carrier layer 31 on the surface of the light-emitting functional layer 10 away from the driving substrate 20 by spin coating or chemical vapor deposition, control the thickness uniformity and cure it.

[0135] For example, the carrier layer 31 may include an epoxy resin and a silicon oxide layer.

[0136] For example, the thickness of the carrier layer 31 is 10 μm to 100 μm.

[0137] The second step is to define the pattern of the light groove 310 using photolithography, and to etch multiple light-emitting grooves 310 on the surface of the carrier layer 31 by dry etching. The groove depth is precisely controlled to expose at least one light-emitting unit 100 below. The groove wall can be designed as an inclined surface or a concave curved surface.

[0138] For example, the wall of the light-emitting groove 310 is a concave spherical surface.

[0139] The advantage of a concave spherical surface lies in its symmetrical light focusing and omnidirectional light collection capabilities. A sphere possesses rotational symmetry and a unique center of curvature, enabling it to reflect scattered light (especially obliquely incident light) emitted from the light-emitting unit 100 at any angle, guiding it towards a positive light path.

[0140] For example, the wall of the light-emitting groove 310 is a concave cylindrical surface.

[0141] A cylindrical concave surface has curvature in only one dimension. Compared to a sphere, a cylindrical surface is simpler to process and can be formed by roll forming or molding, reducing the difficulty of etching the bearing layer 31.

[0142] The third step involves simultaneously depositing a reflective layer 32 on the wall of the light-emitting tank 310 and the top surface of the support layer 31 using magnetron sputtering or evaporation processes to ensure a reflectivity of ≥90%.

[0143] For example, the reflective layer 32 includes at least one of a metal layer and a DBR layer. For instance, the metal layer includes an Ag layer and an Al layer.

[0144] The fourth step involves preparing a convex arc-shaped light-emitting lens 33 within the light-emitting groove 310 by molding with UV-curing adhesive or embedding a pre-formed lens. This ensures that the lens sidewalls are tightly fitted to the groove wall, and the curvature of the arc surface matches the light-gathering requirements, thus completing the integrated brightening functional layer 30.

[0145] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. The data therein represents only illustrative examples. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A light-emitting device, characterized in that, The light-emitting device includes: a light-emitting functional layer (10), a driving substrate (20) and a brightness enhancement functional layer (30). The light-emitting functional layer (10) is located on the driving substrate (20) and includes a plurality of light-emitting units (100) arranged at intervals. The brightening functional layer (30) includes: a carrier layer (31), a reflective layer (32) and a plurality of light-emitting lenses (33). The carrier layer (31) is located on the surface of the light-emitting functional layer (10) away from the driving substrate (20). The surface of the carrier layer (31) has a plurality of light-emitting grooves (310) that expose the light-emitting functional layer (10). Each light-emitting groove (310) exposes at least one light-emitting unit (100). The reflective layer (32) is located at least on the groove wall of each light-emitting groove (310). The light-emitting groove (310) corresponds one-to-one with the light-emitting lens (33). The light-emitting lens (33) is located in the corresponding light-emitting groove (310).

2. The light-emitting device according to claim 1, characterized in that, The orthographic projection of the bottom of the light-emitting groove (310) on the surface of the driving substrate (20) is located within the orthographic projection of the opening of the light-emitting groove (310) on the surface of the driving substrate (20).

3. The light-emitting device according to claim 2, characterized in that, The wall of the light-emitting groove (310) is an inclined surface; or, The wall of the light-emitting groove (310) is a concave curved surface.

4. The light-emitting device according to any one of claims 1 to 3, characterized in that, The reflective layer (32) includes at least one of a metal layer and a DBR layer.

5. The light-emitting device according to any one of claims 1 to 3, characterized in that, The reflective layer (32) is also located on the surface of the carrier layer (31) away from the driving substrate (20).

6. The light-emitting device according to any one of claims 1 to 3, characterized in that, The sidewall of the light-emitting lens (33) is in contact with the wall of the corresponding light-emitting groove (310), and the surface of the light-emitting lens (33) away from the driving substrate (20) is a convex arc surface.

7. The light-emitting device according to any one of claims 1 to 3, characterized in that, The light-emitting unit (100) has opposite light-emitting surfaces and backlighting surfaces, with the light-emitting surfaces being away from the driving substrate (20). At least a portion of the sidewall of the light-emitting unit (100) is an outwardly convex curved surface. The light-emitting unit (100) includes a first semiconductor layer (11), a multi-quantum well layer (12), and a second semiconductor layer (13) stacked sequentially. The surface of the first semiconductor layer (11) away from the second semiconductor layer (13) is the backlight surface. The outwardly convex curved surface is located at least on the sidewall where the multi-quantum well layer (12) is located.

8. The light-emitting device according to claim 7, characterized in that, Each of the light-emitting units (100) has an annular groove (101) on its back surface that exposes the second semiconductor layer (13), and the annular groove (101) surrounds the light-emitting unit (100) around its periphery, and the groove wall of the annular groove (101) is the side wall of each of the light-emitting units (100).

9. The light-emitting device according to any one of claims 1 to 3 and claim 8, characterized in that, The surface of the light-emitting unit (100) away from the driving substrate (20) is a roughened surface, and the brightening functional layer (30) is located on the roughened surface.

10. A method for fabricating a light-emitting device, characterized in that, The preparation method includes: Prepare a light-emitting functional layer (10), the light-emitting functional layer (10) includes a plurality of light-emitting units (100) arranged at intervals. The light-emitting functional layer (10) is bonded to the driving substrate (20); A brightness enhancement layer (30) is formed on the light-emitting functional layer (10). The brightness enhancement functional layer (30) includes a carrier layer (31), a reflective layer (32), and a plurality of light-emitting lenses (33). The carrier layer (31) is located on the surface of the light-emitting functional layer (10) away from the driving substrate (20). The surface of the carrier layer (31) has a plurality of light-emitting grooves (310) that expose the light-emitting functional layer (10). Each light-emitting groove (310) exposes at least one light-emitting unit (100). The reflective layer (32) is located at least on the groove wall of each light-emitting groove (310). The light-emitting groove (310) corresponds one-to-one with the light-emitting lens (33). The light-emitting lens (33) is located in the corresponding light-emitting groove (310).

Images