Display apparatus
By employing an inner and outer lens structure in a Micro LED display device, and utilizing the difference in refractive index between silicon nitride and silicon dioxide, light is refracted twice, solving the problem of thin film peeling caused by an excessively large ratio of microlens height to diameter, and improving light extraction efficiency and product yield.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- WUHAN CHINA STAR OPTOELECTRONICS SEMICONDUCTOR DISPLAY TECHNOLOGY CO LTD
- Filing Date
- 2024-11-22
- Publication Date
- 2026-05-21
AI Technical Summary
In existing Micro LED display devices, an excessively large ratio of microlens height to diameter leads to an increase in the thickness of the silicon dioxide coating, which can easily cause peeling and affect product yield.
It adopts an inner and outer lens structure, with the inner lens made of silicon nitride and the outer lens made of silicon dioxide. The height of the inner lens is greater than that of the outer lens. Collimation of light is achieved through two refractions, avoiding the thin film peeling problem caused by the increase in the thickness of a single lens.
Without increasing the overall lens height, light extraction efficiency was improved, film peeling was avoided, and product yield was increased.
Smart Images
Figure CN2024133783_21052026_PF_FP_ABST
Abstract
Description
Display device Technical Field
[0001] This application relates to the field of display technology, and more specifically to a display device. Background Technology
[0002] In augmented reality (AR) display technology, Micro LED display devices typically employ microlens arrays to improve light extraction efficiency, as shown in Figure 1. Existing Micro LED display devices include a light-emitting device (LED) and a microlens 104. The LED includes a bonding metal layer 101, a light-emitting layer 102, and a transparent conductive layer 103. The microlens 104 is disposed on the LED and is used to concentrate light distribution more vertically, thereby improving light extraction efficiency. This is because the collimating optical system of AR products can only accept light within ±15 degrees, and the higher the parallelism of the light rays, the higher the efficiency of the collimating optical system. However, to achieve high parallelism, a large ratio of the height H to the diameter CD of the microlens 104 is required (H / CD > 1.5), as shown in Figure 2. For example, when the pixel pitch is 4 micrometers, the height of the microlens 104 needs to be greater than 6 micrometers. This requires a thicker silicon dioxide coating, but excessively thick silicon dioxide coatings can easily lead to peeling and other problems, affecting product yield. Invention Overview
[0003] The purpose of embodiments of this application is to provide a display device that improves light extraction efficiency without increasing the total height of the lens.
[0004] An embodiment of this application provides a display device, comprising: a substrate; a driving device layer disposed on the substrate; a light-emitting device, the light-emitting device comprising a bonding metal layer, a light-emitting layer, and a transparent conductive layer, the bonding metal layer being disposed on the driving device layer, the light-emitting layer being disposed on the bonding metal layer, and the transparent conductive layer being disposed on the light-emitting layer; and a lens assembly, the lens assembly comprising an inner lens and an outer lens, the inner lens being disposed on a corresponding light-emitting device, the outer lens being disposed around the inner lens, and the refractive index of the inner lens being greater than the refractive index of the outer lens. Beneficial effects
[0005] The display device provided in this application achieves effective light collimation through the cooperation of inner and outer double-layer lenses. Specifically, the inner lens is made of silicon nitride, and the outer lens is made of silicon dioxide. The difference in refractive index between the two materials (silicon nitride refractive index 1.75-1.85, silicon dioxide refractive index 1.45-1.50) forms two refractive interfaces along the light propagation path. When light is emitted from the light-emitting layer, it first undergoes a first refraction through the inner lens. Due to the higher refractive index of the inner lens, it can refract large-angle divergent light into small-angle light. Then, it undergoes a second refraction through the outer lens, further collimating the small-angle light and ultimately making the divergent light more parallel. Since the height of the inner lens is greater than that of the outer lens, and at least a portion of the inner lens is fitted inside the outer lens, a good light collimation effect can be achieved through two refractions without increasing the total lens height, thus improving light extraction efficiency. This avoids the problem of increasing the silicon dioxide coating thickness to achieve the same light extraction efficiency with traditional single-layer lenses, which leads to film peeling. Attached Figure Description
[0006] Figure 1 is a schematic diagram of a first technical solution for a lens mounted on a light-emitting device in an existing display device.
[0007] Figure 2 is a schematic diagram of a second technical solution for a lens mounted on a light-emitting device in an existing display device.
[0008] Figure 3 is a schematic diagram of a display device provided in an embodiment of this application.
[0009] Figure 4 is a schematic diagram of a lens disposed on a light-emitting device in a display device provided in an embodiment of this application.
[0010] Figure 5 is a schematic diagram comparing the light efficacy of the preferred technical solution of this application with two existing technical solutions. Embodiments of the present invention
[0011] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.
[0012] The terms “first,” “second,” and similar words do not indicate any order, quantity, or importance, but are merely used to distinguish different technical features. The terms “multiple,” and similar words mean two or more, unless otherwise expressly specified.
[0013] The embodiments of this application can be combined with each other.
[0014] As shown in Figure 3, the display device provided in the embodiments of this application can be, for example, a Micro-LED display device. This display device includes a display panel, a source driving circuit, a gate driving circuit, a timing controller, a light-emitting controller, and a power management chip. The display panel includes a substrate, data lines (DATA), scan lines (SCAN), power lines (VDD, VSS), light-emitting control signal lines (EM), a pixel array, etc.
[0015] The substrate can be, for example, a glass substrate, a flexible substrate (e.g., a polyimide substrate), etc. The pixel array is composed of multiple pixel units PX arranged in rows and columns. Each pixel unit PX includes a light-emitting device and a pixel driving circuit. The pixel driving circuit is electrically connected to the light-emitting device and is used to control the brightness of each light-emitting device in the display device. Each gate driving unit in the gate driving circuit controls a corresponding row of pixel units PX. The source driving circuit provides data signals to the pixel units PX. The timing controller receives externally input image data and synchronization signals, and generates the signals required by the gate driving circuit and the source driving circuit. The power management chip provides the necessary operating voltage to various parts of the display device.
[0016] Furthermore, the display device provided in the embodiments of this application may also integrate an embedded touch circuit, which is used to implement touch functionality.
[0017] As shown in Figure 4, the display device provided in the embodiments of this application includes a substrate, a driving device layer, a light-emitting device, and a lens assembly. The driving device layer is disposed on the substrate. The light-emitting device includes a bonding metal layer 401, a light-emitting layer 402, and a transparent conductive layer 403. The bonding metal layer 401 is disposed on the driving device layer, the light-emitting layer 402 is disposed on the bonding metal layer 401, and the transparent conductive layer 403 is disposed on the light-emitting layer 402. The lens assembly includes an inner lens 405 and an outer lens 404. The inner lens 405 is disposed on the corresponding light-emitting device, and the outer lens 404 is disposed (sleeved) around the inner lens 405. The refractive index of the inner lens 405 is greater than the refractive index of the outer lens 404.
[0018] At least a portion of the inner lens 405 is fitted inside the outer lens 404. The diameter of the outer lens 404 is larger than the diameter of the inner lens 405, and the height of the inner lens 405 is greater than the height of the outer lens 404.
[0019] The spacing between two adjacent light-emitting devices is 4 micrometers.
[0020] The lens assembly is used to convert a diverging beam into a collimated beam within a range of ±15 degrees.
[0021] In one specific embodiment, the substrate may be a silicon substrate, and the driving device layer includes a driving transistor array. The bonding metal layer 401 in the light-emitting device is made of a gold-tin alloy; the light-emitting layer 402 is a Micro-LED chip, including an active region and a quantum well structure; and the transparent conductive layer 403 is indium tin oxide (ITO). The inner lens 405 and outer lens 404 in the lens assembly both extend in a direction perpendicular to the substrate away from the driving device layer, and their central axes coincide.
[0022] The angle between the sidewall of the light-emitting layer 402 and the normal of the substrate can be controlled within the range of 75 degrees to 90 degrees.
[0023] A transparent conductive layer 403 covers the top and sides of the light-emitting layer 402.
[0024] The surfaces of both the inner lens 405 and the outer lens 404 are convex arc surfaces, that is, the surfaces of both the inner lens 405 and the outer lens 404 are spherical.
[0025] The spherical outer surfaces of the inner lens 405 and the outer lens 404 can be formed by photolithography. The spherical shape helps to control the direction of light emission, making it easier for light to converge within a predetermined field of view.
[0026] The transition area between the two lenses is an arc surface, and the width of the transition area is in the range of 0.1 micrometers to 0.3 micrometers.
[0027] The curvature of the surface of the inner lens 405 ranges from 80 to 130 degrees; the curvature of the surface of the outer lens 404 ranges from 60 to 90 degrees.
[0028] The curvature range of the inner lens 405 (80 to 130°) is greater than that of the outer lens 404 (60 to 90°). This allows light to undergo a stronger first refraction when passing through the inner lens 405, and then be further collimated when passing through the outer lens 404. The larger curvature of the inner lens 405 provides stronger refractive power, while the smaller curvature of the outer lens 404 can adjust the light that has already undergone the first refraction, reducing the deflection angle of the light.
[0029] The inner lens 405 is made of silicon nitride, and the outer lens 404 is made of silicon dioxide.
[0030] The refractive index difference between the materials of the inner lens 405 and the outer lens 404 is greater than or equal to 0.25 and less than or equal to 0.4. The refractive index difference of 0.25 to 0.4 ensures that light can produce sufficient refraction at the interface of the two lenses, while avoiding excessive interface reflection loss due to an excessive refractive index difference.
[0031] The refractive index of the inner lens 405 is in the range of 1.7 to 1.9, preferably in the range of 1.75 to 1.85; the refractive index of the outer lens 404 is in the range of 1.45 to 1.50.
[0032] The inner lens 405 uses silicon nitride, whose refractive index can be adjusted within the range of 1.7 to 1.9 by regulating deposition process parameters (such as gas ratio, temperature, and pressure). Optimal light extraction efficiency is achieved when the refractive index is controlled within the range of 1.75 to 1.85. The outer lens 404 uses silicon dioxide, whose refractive index is in the range of 1.45 to 1.50. This range of refractive index ensures both good optical performance and the density and stability of the thin film.
[0033] The height of the inner lens 405 is greater than 1.1 times the height of the outer lens 404 and less than 1.5 times the height of the outer lens 404.
[0034] This height ratio ensures that light undergoes a strong first refraction when passing through the inner lens 405, and then a second refraction at the outer lens 404, while avoiding the problem of silicon dioxide coating peeling caused by excessive total height.
[0035] The inner lens 405 has a height range of 0.012 mm to 0.018 mm; the outer lens 404 has a height range of 0.010 mm to 0.015 mm. Within this height range, the stress on the lens can be effectively controlled, preventing cracking or peeling.
[0036] As an improvement, the sidewall of the inner lens 405 includes multiple first steps, the transition area of which is chamfered with an angle of 30 to 45 degrees. The inner wall of the outer lens 404 has a second step that mates with the first step. The contact interface between the two lenses is stepped.
[0037] The diameter of the outer lens 404 is 1.1 times larger than the diameter of the inner lens 405 and 1.5 times smaller than the diameter of the inner lens 405.
[0038] The ratio between the diameter of the outer lens 404 and the diameter of the inner lens 405 ensures that the light is fully refracted by the inner lens 405, while also reserving enough edge area for the outer lens 404 to collect divergent light at large angles.
[0039] As an improvement, an annular reinforcing rib is provided at the bottom edge region of the outer lens 404, and the height of the reinforcing rib is 10% to 20% of the height of the outer lens 404. A locking part is provided at the junction of the inner and outer lenses 404, and the locking angle of the locking part is 60 degrees to 75 degrees.
[0040] The reinforcing rib has a trapezoidal cross-section, with the upper base width smaller than the lower base width, forming an outwardly inclined support surface. At the junction of the bottom of the inner lens 405 and the outer lens 404, there is a protrusion and a recess, which interlock. The protrusion has a dovetail-shaped cross-section, and the recess matches the cross-section of the protrusion. The interlocking protrusion and recess are evenly distributed along the circumference of the lens, forming a ring-shaped interlocking structure. The outer surface of the outer lens 404 has a periodically arranged array of anti-reflective microprisms, with the prism lines arranged radially. The bottom of the inner lens 405 has a positioning reference surface, which is in close contact with the top surface of the light-emitting device to ensure the optical axes of the inner and outer lenses 404 are aligned.
[0041] The inner lens 405 has a diameter ranging from 0.016 mm to 0.024 mm; the outer lens 404 has a diameter ranging from 0.020 mm to 0.030 mm.
[0042] The diameter range of the inner lens 405 and the diameter range of the outer lens 404 are matched to the pixel size. These diameter ranges ensure complete coverage of the light emitted by a single pixel by the lens, while avoiding optical crosstalk between adjacent pixels.
[0043] The surface roughness of the inner lens 405 and the outer lens 404 is less than 5 nanometers.
[0044] The inner lens 405 has a positioning boss on its outer periphery, and the outer lens 404 has an annular groove on its inner periphery that matches the positioning boss.
[0045] The inner lens 405 has an annular positioning boss and radial positioning posts on its outer periphery. The top surface of the annular positioning boss is inclined, forming a self-aligning structure with the inner wall of the outer lens 404. The radial positioning posts are evenly distributed circumferentially, and each positioning post has a guide groove on its side. The inner periphery of the outer lens 404 has an annular groove and positioning holes that mate with the annular positioning boss and radial positioning posts. The cross-section of the annular groove is dovetail-shaped to prevent lens separation. The inner wall of the positioning hole has ribs that mate with the guide groove. The contact surfaces of the two lenses have staggered protrusions and recesses, which interlock.
[0046] The inner lens 405 has an annular light-limiting member at its edge, which includes multiple stepped light-blocking steps. Each step has a serrated surface with the inclined surface of the serration facing the center of the lens. When large-angle scattered light is incident on the surface of the serration, it is guided to the light-absorbing layer after multiple reflections. Refractive surfaces are provided between the steps to refract some of the large-angle light back to the central area of the inner lens 405.
[0047] The height-to-diameter ratio of the inner lens 405 ranges from 0.75 to 1.0; the height-to-diameter ratio of the outer lens 404 ranges from 0.4 to 0.6.
[0048] The above ratio ensures that the lens has sufficient refractive power and avoids stress problems caused by an excessively large ratio.
[0049] The axes of the inner lens 405 and the outer lens 404 coincide. This ensures that the light rays maintain a symmetrical distribution when passing through the two lenses.
[0050] The intensity half-angle range of the lens assembly is 25 to 30 degrees. Within this angle range, the light intensity attenuation does not exceed 50%, ensuring that the light can be effectively received by the collimating optical system while guaranteeing the uniformity of the display device's brightness.
[0051] The inner lens 405 has multiple concentric annular steps on its sidewalls. The surface of each step is a micro-arc surface, which can refract the incident light twice. The inner wall of the outer lens 404 has stepped grooves that match the steps, and the steps and grooves form a composite refractive interface.
[0052] The inner lens 405 has a spherical cap surface with concentric, periodically varying annular gratings. The grating is divided into multiple regions from the center to the edge, with the grating period gradually increasing within each region, and the grating periods of adjacent regions changing proportionally. This allows for different degrees of diffraction of light rays at different incident angles, making the light rays tend to be parallel after transmission. The outer lens 404 has multiple concentric annular stepped surfaces on its surface, the height and tilt angle of each stepped surface matching the period of the corresponding grating on the inner lens 405. The grating of the inner lens 405 and the stepped surfaces of the outer lens 404 cooperate to form a composite optical interface, enabling more precise control of the light propagation direction.
[0053] The lens assembly has an annular stress buffer region on its periphery, which includes multiple corrugated elastic support members evenly distributed circumferentially. Each elastic support member consists of three layers of corrugated members, with alternating crests and troughs, and adjacent corrugations connected by transition arc surfaces. The corrugated members can produce slight deformations in the radial and axial directions, thereby alleviating stress caused by thermal expansion. One end of the elastic support member is fixedly connected to the inner lens 405, and the other end has a sliding groove structure. This sliding groove structure cooperates with the annular guide rail of the outer lens 404, allowing the elastic support member to slide back and forth radially, thereby compensating for deformation caused by thermal stress.
[0054] The light extraction efficiency of the lens assembly ranges from 23% to 27% within a field of view of ±15 degrees.
[0055] The light extraction efficiency of the lens assembly is improved by 25% to 35% compared to the absence of a lens assembly.
[0056] The display device provided in this application achieves effective light collimation through the cooperation of inner and outer double-layer lenses. Specifically, the inner lens 405 is made of silicon nitride, and the outer lens 404 is made of silicon dioxide. The difference in refractive index between the two materials (silicon nitride refractive index 1.75-1.85, silicon dioxide refractive index 1.45-1.50) forms two refractive interfaces along the light propagation path. When light is emitted from the light-emitting layer 402, it first undergoes a first refraction through the inner lens 405. Due to the higher refractive index of the inner lens 405, it can refract large-angle divergent light into small-angle light. Then, it undergoes a second refraction through the outer lens 404, further collimating the small-angle light and ultimately making the divergent light more parallel. Since the height of the inner lens 405 is greater than the height of the outer lens 404, and at least a portion of the inner lens 405 is fitted inside the outer lens 404, a good light collimation effect can be achieved through two refractions without increasing the total lens height, thus improving light extraction efficiency. This avoids the problem of traditional single-layer lenses having to increase the thickness of the silicon dioxide coating to achieve the same light extraction efficiency, which leads to film peeling.
[0057] As shown in Figure 4, an embodiment of this application provides a display device employing a double-layer nested structure of an inner lens 405 and an outer lens 404, wherein the inner lens 405 is made of silicon nitride and the outer lens 404 is made of silicon dioxide. The display device provided by this application can effectively improve light extraction efficiency without increasing the overall lens height, thereby reducing the problem of thin-film peeling caused by excessive lens height and reducing yield loss.
[0058] Specifically, the display device provided in the embodiments of this application includes: a substrate, a driving device layer, a light-emitting device, and a lens assembly. The driving device layer is disposed on the substrate. The light-emitting device includes a bonding metal layer 401, a light-emitting layer 402, and a transparent conductive layer 403. The bonding metal layer 401 is disposed on the driving device layer, the light-emitting layer 402 is disposed on the bonding metal layer 401, and the transparent conductive layer 403 is disposed on the light-emitting layer 402. The lens assembly includes an inner lens 405 and an outer lens 404. Both the inner lens 405 and the outer lens 404 are disposed on the transparent conductive layer 403. At least a portion of the inner lens 405 is fitted inside the outer lens 404. The diameter of the outer lens 404 is larger than the diameter of the inner lens 405, and the height of the inner lens 405 is greater than the height of the outer lens 404.
[0059] Both the inner lens 405 and the outer lens 404 have convex curved surfaces, i.e., spherical cap shapes. The curvature of the inner lens 405 surface ranges from 80 to 130 degrees, and the curvature of the outer lens 404 surface ranges from 60 to 90 degrees. The refractive index of the inner lens 405 ranges from 1.75 to 1.85, and the refractive index of the outer lens 404 ranges from 1.45 to 1.50. The difference in refractive index between the two materials is greater than 0.25 and less than 0.4.
[0060] The height of the inner lens 405 ranges from 0.012 mm to 0.018 mm, and the height of the outer lens 404 ranges from 0.010 mm to 0.015 mm. The height of the inner lens 405 is greater than 1.1 times and less than 1.5 times the height of the outer lens 404. Within this height range, the stress on the lens can be effectively controlled, preventing cracking or peeling.
[0061] The inner lens 405 has a diameter ranging from 0.016 mm to 0.024 mm, while the outer lens 404 has a diameter ranging from 0.020 mm to 0.030 mm. The diameter of the outer lens 404 is greater than 1.1 times and less than 1.5 times the diameter of the inner lens 405. This diameter ratio ensures complete coverage of the light emitted by a single pixel while avoiding optical crosstalk between adjacent pixels.
[0062] The height-to-diameter ratio of the inner lens 405 ranges from 0.75 to 1.0, while the height-to-diameter ratio of the outer lens 404 ranges from 0.4 to 0.6. This ratio ensures that the lens has sufficient refractive power while avoiding stress problems caused by an excessively large ratio.
[0063] The inner lens 405 and the outer lens 404 have coincident axes, ensuring that light rays maintain a symmetrical distribution when passing through the two lenses. The intensity half-angle of the lens assembly ranges from 25 to 30 degrees. Within this angle range, the light intensity attenuation does not exceed 50%, ensuring that the light rays can be effectively received by the subsequent collimating optical system.
[0064] The spacing between two adjacent light-emitting devices is 4 micrometers. Combined with the lens assembly of the embodiment of this application, a high display resolution can be achieved.
[0065] To better illustrate the technical effects of this application, detailed descriptions are provided below through specific embodiments and comparative examples. Table 1 lists the specific parameter configurations of the inner and outer lenses 404 in different embodiments and their corresponding optical performance indicators. Wherein, code 1 represents the inner lens 405, code 2 represents the outer lens 404; radius refers to the radius of the lens; the refractive index of SiO (silicon dioxide) in the material is 1.48, and the refractive index of SiN (silicon nitride) is 1.8; the curvature value is used to define the arc of the lens surface, making the lens surface form a spherical cap shape with a specific curvature; eccentricity represents the height of the lens, i.e., the distance from the emitting surface to the top of the lens; H / CD represents the ratio of the lens height H to the lens diameter (CD), where the lens diameter (CD) refers to the diameter at the widest point at the bottom of the lens, i.e., the diameter at the point where the lens contacts the emitting surface, which is equal to twice the lens radius; the intensity half-angle represents the emission angle corresponding to a 50% reduction in light intensity.
[0066]
[0067] Table 1
[0068] The existing technology achieves a light extraction efficiency of 19% within ±15 degrees. Example 5 (preferred) of this application achieves a light extraction efficiency of 25% within ±15 degrees. Example 5 (preferred) of this application represents a 28% efficiency improvement compared to the existing technology.
[0069] Table 2
[0070] By analyzing the data in Table 1 and Figure 5, the following conclusions can be drawn:
[0071] A comparison of existing technologies (Technologies 1 and 2) reveals significant limitations of single-layer silica lenses. Technology 1 employs a relatively low height-to-diameter ratio (H / CD = 0.50), resulting in structural stability but an intensity half-angle of 34 degrees, leading to unsatisfactory light extraction. Technology 2 reduces the intensity half-angle to 24 degrees by increasing the height-to-diameter ratio (H / CD = 1.00), but this excessively high silica lens height can easily cause film peeling issues.
[0072] The dual-layer lenses provided in this application (Examples 1 to 5) exhibit better overall performance. In particular, Example 5, as a preferred embodiment, features an inner silicon nitride lens with a radius of 0.01 mm, a curvature of 125.0, and a height-to-diameter ratio of 0.9375; and an outer silicon dioxide lens with a radius of 0.012 mm, a curvature of 83.3, and a height-to-diameter ratio of 0.50. This configuration achieves a 27-degree intensity half-angle while maintaining a moderate overall height, resulting in good light collimation and thus improved light extraction efficiency.
[0073] As can be seen from the comparison between Example 3 and other examples, the material configuration order of the inner and outer lens 404 has a significant impact on optical performance. When silicon dioxide is used as the material of the inner lens 405 and silicon nitride is used as the material of the outer lens 404 (Example 3), the intensity half-angle increases to 41 degrees. This verifies that the configuration of using silicon nitride, which has a higher refractive index, as the material of the inner lens 405 and silicon dioxide, which has a lower refractive index, as the material of the outer lens 404 is more conducive to light collimation.
[0074] A comparison of parameters in Examples 4 and 5 shows that by optimizing the curvature and aspect ratio of the lens, light extraction efficiency can be improved while maintaining structural stability. Example 4 uses a larger aspect ratio (1.875) for the inner lens 405, resulting in a smaller intensity half-angle (25.5 degrees), but this may introduce stress issues. In contrast, Example 5 reduces the aspect ratio of the inner lens 405 to 0.9375. Although the intensity half-angle increases slightly (27 degrees), the structure is more stable, making it a superior technical solution.
[0075] As can be seen from the data in Table 2, the preferred embodiment of this application (Example 5) achieves a light extraction efficiency of 25% within a ±15-degree field of view, while the prior art achieves only 19% light extraction efficiency within the same field of view. Calculations show that the preferred embodiment of this application improves efficiency by 28% compared to the prior art. This efficiency improvement stems from the double refraction of light by the double-layer lens, which confines more light within a ±15-degree field of view, thereby improving the receiving efficiency of the subsequent optical system.
[0076] In the display device provided in the embodiments of this application, when light is emitted from the light-emitting layer 402, it first undergoes a first refraction through the inner lens 405. Since the inner lens 405 is made of silicon nitride with a refractive index of 1.75 to 1.85, it can strongly refract light rays diverging at large angles, significantly reducing their deflection angle. Subsequently, the light enters the outer lens 404. Since the outer lens 404 is made of silicon dioxide with a refractive index of 1.45 to 1.50, lower than the refractive index of the inner lens 405, it can perform a second refraction on the light rays that have already undergone the first refraction. This double refraction effect allows the diverging light rays to form a collimated beam within a field of view of ±15 degrees, and the intensity half-angle of the lens assembly is controlled within the range of 25 to 30 degrees, ensuring that the light intensity attenuation does not exceed 50%, thereby significantly improving the light extraction efficiency. The height of the inner lens 405 is greater than the height of the outer lens 404; this height difference allows light to pass through two refraction interfaces at different heights while maintaining a constant total height. Compared to traditional single-layer silicon dioxide lenses, the double-layer lens of this application can improve light extraction efficiency without increasing the thickness of the silicon dioxide coating.
[0077] The manufacturing process of the display device provided in the embodiments of this application includes:
[0078] A driving device layer is formed on the substrate.
[0079] A bonding metal layer 401, a light-emitting layer 402, and a transparent conductive layer 403 are sequentially formed on the driving device layer.
[0080] An inner lens 405 of silicon nitride material is formed on the transparent conductive layer 403.
[0081] An outer lens 404 made of silicon dioxide material is formed around the inner lens 405.
[0082] In this process, both the inner lens 405 and the outer lens 404 are patterned after depositing material layers to form a spherical surface. This manufacturing method avoids the peeling problem caused by excessively thick silicon dioxide coating in traditional single-layer high-resolution lenses. By rationally controlling the size ratio of the inner and outer lens 404, the stress of the entire lens assembly is effectively controlled, thereby improving the product yield.
[0083] The embodiments of this application have been described in detail above. The content of this specification should not be construed as limiting the scope of protection of this application.
Claims
1. A display device, comprising: substrate; A driving device layer disposed on the substrate; A light-emitting device, comprising a bonding metal layer, a light-emitting layer, and a transparent conductive layer, wherein the bonding metal layer is disposed on the driving device layer, the light-emitting layer is disposed on the bonding metal layer, and the transparent conductive layer is disposed on the light-emitting layer; as well as A lens assembly, comprising an inner lens and an outer lens, wherein the inner lens is disposed on a corresponding light-emitting device, and the outer lens is disposed around the inner lens, and the refractive index of the inner lens is greater than that of the outer lens.
2. The display device according to claim 1, wherein At least a portion of the inner lens is fitted inside the outer lens, the diameter of the outer lens is larger than the diameter of the inner lens, and the height of the inner lens is greater than the height of the outer lens.
3. The display device according to claim 1, wherein Both the inner and outer lenses have convex curved surfaces. The curvature of the inner lens surface ranges from 80 to 130 degrees, and the curvature of the outer lens surface ranges from 60 to 90 degrees.
4. The display device according to claim 1, wherein The inner lens is made of silicon nitride, and the outer lens is made of silicon dioxide.
5. The display device according to claim 1, wherein The difference in refractive index between the materials of the inner lens and the outer lens is greater than or equal to 0.25 and less than or equal to 0.
4.
6. The display device of claim 5, wherein, The refractive index of the inner lens ranges from 1.7 to 1.9; The refractive index of the outer lens ranges from 1.45 to 1.
50.
7. The display device according to claim 1, wherein The height of the inner lens is greater than 1.1 times the height of the outer lens and less than 1.5 times the height of the outer lens.
8. The display device according to claim 1, wherein The height of the inner lens ranges from 0.012 mm to 0.018 mm; The height of the outer lens ranges from 0.010 mm to 0.015 mm.
9. The display device according to claim 1, wherein The diameter of the outer lens is greater than 1.1 times the diameter of the inner lens and less than 1.5 times the diameter of the inner lens.
10. The display device according to claim 1, wherein The diameter of the inner lens ranges from 0.016 mm to 0.024 mm; The diameter of the outer lens ranges from 0.020 mm to 0.030 mm.
11. The display device according to claim 1, wherein The ratio of the height to the diameter of the inner lens ranges from 0.75 to 1.0; The ratio of the height to the diameter of the outer lens ranges from 0.4 to 0.
6.
12. The display device according to claim 1, wherein The axes of the inner lens and the outer lens coincide.
13. The display device of claim 1, wherein, The intensity half-angle range of the lens assembly is 25 degrees to 30 degrees.
14. The display device of claim 1, wherein, The inner lens has an annular positioning boss on its outer periphery, the top surface of which is an inclined surface, and the outer lens has an annular groove on its inner periphery that mates with the annular positioning boss.
15. The display device of claim 1, wherein, The inner lens has radial positioning posts on its outer periphery, which are evenly distributed circumferentially, and the outer lens has positioning holes on its inner periphery that mate with the radial positioning posts.
16. The display device of claim 15, wherein, The radial positioning post has a guide groove on its side, and the inner wall of the positioning hole has a rib that mates with the guide groove.
17. The display device of claim 1, wherein, The bottom edge region of the outer lens is provided with an annular reinforcing rib, and the cross-section of the annular reinforcing rib is trapezoidal.
18. The display device of claim 17, wherein, The height of the annular reinforcing rib is 10% to 20% of the height of the outer lens.
19. The display device of claim 1, wherein, The side wall of the inner layer lens is provided with a plurality of annular steps, and the inner wall of the outer layer lens is provided with a stepped groove matched with the steps.
20. The display device of claim 1, wherein, The spherical cap surface of the inner layer lens is provided with an annular grating, and a grating period of the grating gradually increases from the center to the edge.