Display device

Abstract

The application provides a display device, which comprises a substrate, a driving device layer, a light-emitting device and a lens assembly. The driving device layer is arranged on the substrate, the light-emitting device comprises a bonding metal layer, a light-emitting layer and a transparent conductive layer, the bonding metal layer is arranged on the driving device layer, the light-emitting layer is arranged on the bonding metal layer, and the transparent conductive layer is arranged on the light-emitting layer. The lens assembly comprises an inner layer lens and an outer layer lens, the inner layer lens is arranged on the corresponding light-emitting device, the inner layer lens is made of silicon nitride, the outer layer lens is made of silicon dioxide, the outer layer lens is arranged on the periphery of the inner layer lens, and the refractive index of the inner layer lens is greater than that of the outer layer lens. The display device provided by the application improves the light extraction efficiency without increasing the total height of the lens.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a display device. BACKGROUND

[0002] In the augmented reality (AR) display technology, a micro LED display device usually adopts a microlens array to improve the light extraction efficiency of the display device. As shown in FIG. 1, the existing micro LED display device includes a light emitting device and a microlens 104, the light emitting device includes a bonding metal layer 101, a light emitting layer 102 and a transparent conductive layer 103, and the microlens 104 is arranged on the light emitting device. The microlens 104 is used to make the light distribution more concentrated in the vertical direction, so as to improve the light extraction efficiency. This is because the collimating optical system of the AR product can only accept light within ±15 degrees, and the higher the parallelism of the light, the higher the efficiency of the collimating optical system. However, to obtain a higher parallelism, a larger ratio of the height H to the diameter CD of the microlens 104 (H / CD>1.5) is required, as shown in FIG. 2. For example, when the pixel pitch is 4 microns, the height of the microlens 104 needs to be greater than 6 microns. This requires a thicker silicon dioxide coating, and an excessively thick silicon dioxide coating is prone to peeling and other problems, which affects the product yield. Figure 1 SUMMARY Figure 2 The embodiments of the present application provide a display device to improve the light extraction efficiency without increasing the total height of the lens.

[0003] The embodiments of the present application provide a display device, which includes a substrate, a driving device layer arranged on the substrate, a light emitting device including a bonding metal layer, a light emitting layer and a transparent conductive layer, the bonding metal layer being arranged on the driving device layer, the light emitting layer being arranged on the bonding metal layer, and the transparent conductive layer being arranged on the light emitting layer, and a lens assembly including an inner layer lens and an outer layer lens, the inner layer lens being arranged on the corresponding light emitting device, the outer layer lens being arranged on the periphery of the inner layer lens, and the refractive index of the inner layer lens being greater than the refractive index of the outer layer lens.

[0004] In the above display device, at least a part of the inner layer lens is sleeved in the outer layer lens, the diameter of the outer layer lens is greater than the diameter of the inner layer lens, and the height of the inner layer lens is greater than the height of the outer layer lens.

[0005] In the above display device, the surfaces of the inner layer lens and the outer layer lens are both convex arc surfaces, the curvature range of the surface of the inner layer lens is 80 to 130, and the curvature range of the surface of the outer layer lens is 60 to 90.

[0006] In the above display device, the surfaces of the inner layer lens and the outer layer lens are both convex arc surfaces, the curvature range of the surface of the inner layer lens is 80 to 130, and the curvature range of the surface of the outer layer lens is 60 to 90. ​

[0007] In the display device, the material of the inner lens is silicon nitride, and the material of the outer lens is silicon dioxide.

[0008] In the display device, a difference between the refractive indexes of 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.

[0009] In the display device, the refractive index of the inner lens ranges from 1.7 to 1.9, and the refractive index of the outer lens ranges from 1.45 to 1.50.

[0010] In the display device, 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.

[0011] In the display device, 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.

[0012] In the display device, a ratio of the height to the diameter of the inner lens ranges from 0.75 to 1.0, and a ratio of the height to the diameter of the outer lens ranges from 0.4 to 0.6.

[0013] In the display device, the axes of the inner lens and the outer lens coincide.

[0014] In the display device, the intensity half angle of the lens assembly ranges from 25 degrees to 30 degrees.

[0015] The display device provided in the present application realizes effective collimation of light through cooperation of the 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 between the refractive indexes of the two materials (the refractive index of silicon nitride is 1.75-1.85, and the refractive index of silicon dioxide is 1.45-1.50) forms two refractive interfaces on the light propagation path. After the light is emitted from the light-emitting layer, it is first refracted by the inner lens for the first time. Since the inner lens has a relatively high refractive index, it can refract the light with a large angle of divergence into light with a small angle of divergence. Then, the light is refracted by the outer lens for the second time, which further collimates the light with a small angle of divergence, so that the divergent light becomes more parallel. Since the height of the inner lens is greater than the height of the outer lens, and at least a part of the inner lens is sleeved in the outer lens, the light can be effectively collimated through two times of refraction without increasing the total height of the lens, that is, the light extraction efficiency is improved. This avoids the problem of film peeling caused by increasing the thickness of the silicon dioxide coating in the traditional single-layer lens structure to obtain the same light extraction efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1This is a schematic diagram of the first technical solution of a lens mounted on a light-emitting device in an existing display device.

[0017] Figure 2 This is a schematic diagram of a second technical solution for a lens mounted on a light-emitting device in an existing display device.

[0018] Figure 3 This is a schematic diagram of a display device provided in an embodiment of this application.

[0019] Figure 4 This is a schematic diagram of a lens disposed on a light-emitting device in a display device provided in an embodiment of this application.

[0020] Figure 5 This is a schematic diagram comparing the light efficacy of the preferred technical solution of this application with two existing technical solutions. Detailed Implementation

[0021] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0022] 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.

[0023] The embodiments of this application can be combined with each other.

[0024] like Figure 3 As shown, 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.

[0025] 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.

[0026] In addition, the display device provided by the embodiment of the present application can also integrate an in-cell touch circuit, and the touch circuit is used to realize a touch function.

[0027] As shown in Figure 4 The display device provided by the embodiment of the present application comprises a substrate, a driving device layer, a light emitting device and a lens assembly. The driving device layer is arranged on the substrate. The light emitting device comprises a bonding metal layer 401, a light emitting layer 402 and a transparent conductive layer 403. The bonding metal layer 401 is arranged on the driving device layer, the light emitting layer 402 is arranged on the bonding metal layer 401, and the transparent conductive layer 403 is arranged on the light emitting layer 402. The lens assembly comprises an inner layer lens 405 and an outer layer lens 404.

[0028] The inner layer lens 405 is arranged on the corresponding light emitting device, and the outer layer lens 404 is arranged (sleeved) on the periphery of the inner layer lens 405. The refractive index of the inner layer lens 405 is greater than the refractive index of the outer layer lens 404.

[0029] At least a part of the inner layer lens 405 is sleeved in the outer layer lens 404. The diameter of the outer layer lens 404 is greater than the diameter of the inner layer lens 405, and the height of the inner layer lens 405 is greater than the height of the outer layer lens 404.

[0030] The distance between two adjacent light emitting devices is 4 microns.

[0031] The lens assembly is used to convert a divergent light beam into a collimated light beam within a range of ±15 degrees.

[0032] In one specific embodiment, the substrate can be a silicon substrate, and the driving device layer comprises an array of driving transistors. The bonding metal layer 401 in the light emitting device adopts a gold-tin alloy material; the light emitting layer 402 is a Micro-LED chip, which comprises an active region and a quantum well structure; and the transparent conductive layer 403 is indium tin oxide (ITO). The inner layer lens 405 and the outer layer lens 404 in the lens assembly both extend in a direction perpendicular to the substrate and away from the driving device layer, and the central axes of the two coincide.

[0033] The included angle between the sidewall of the light emitting layer 402 and the normal line of the substrate can be controlled within a range of 75 degrees to 90 degrees.

[0034] The transparent conductive layer 403 covers the top surface and the side surface of the light emitting layer 402.

[0035] The surfaces of the inner layer lens 405 and the outer layer lens 404 are both convex arcs, i.e., the surfaces of the inner layer lens 405 and the outer layer lens 404 are both spherical caps.

[0036] The spherical crown-shaped outer surface of the inner lens 405 and the outer lens 404 can be formed by a photolithography process. The spherical crown shape is advantageous for controlling the exit direction of light rays, making it easier for the light rays to converge within a predetermined field of view angle range.

[0037] The transition region of the two lenses is a circular arc surface, and the width of the transition region is in the range of 0.1 microns to 0.3 microns.

[0038] The curvature range of the surface of the inner lens 405 is 80 to 130; the curvature range of the surface of the outer lens 404 is 60 to 90.

[0039] The curvature range of the inner lens 405 (80 to 130) is greater than the curvature range of the outer lens 404 (60 to 90), which can make the light rays obtain a stronger first refraction when passing through the inner lens 405, and then further collimate when passing through the outer lens 404. The inner lens 405 with a larger curvature can provide stronger refraction capability, while the outer lens 404 with a smaller curvature can adjust the light rays that have been subjected to the first refraction, reducing the deflection angle of the light rays.

[0040] The material of the inner lens 405 is silicon nitride, and the material of the outer lens 404 is silicon dioxide.

[0041] The refractive index difference of 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. A refractive index difference of 0.25 to 0.4 ensures that the light rays can produce sufficient refraction at the interface of the two lenses, while not causing excessive interface reflection loss due to a too large refractive index difference.

[0042] The refractive index range of the inner lens 405 is 1.7 to 1.9, and preferably, the refractive index range of the inner lens 405 is 1.75 to 1.85; the refractive index range of the outer lens 404 is 1.45 to 1.50.

[0043] The silicon nitride material used for the inner lens 405 has a refractive index that can be adjusted in the range of 1.7 to 1.9 by adjusting the deposition process parameters (such as gas ratio, temperature, pressure, etc.). When the refractive index is controlled in the range of 1.75 to 1.85, the best light extraction efficiency can be obtained. The silicon dioxide material used for the outer lens 404 has a refractive index that can be adjusted in the range of 1.45 to 1.50 by a plasma enhanced chemical vapor deposition (PECVD) process. A refractive index in this range ensures good optical performance, as well as the density and stability of the thin film.

[0044] 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.

[0045] The high ratio relationship makes the light obtain a strong first refraction when passing through the inner lens 405, and then obtains a second refraction at the outer lens 404, while avoiding the problem of peeling of the silicon dioxide coating caused by excessive total height.

[0046] The height of the inner lens 405 ranges from 0.012 mm to 0.018 mm; the height of the outer lens 404 ranges from 0.010 mm to 0.015 mm. In this height range, the stress of the lens can be effectively controlled to avoid cracking or peeling.

[0047] As an improvement, the sidewall of the inner lens 405 includes a plurality of first steps, and the transition area of the first step is chamfered, and the chamfer angle is 30 to 45 degrees. The inner wall of the outer lens 404 is provided with a second step matched with the step. The contact interface of the two layers of lenses is stepped.

[0048] The diameter of the outer lens 404 is greater than 1.1 times the diameter of the inner lens 405 and less than 1.5 times the diameter of the inner lens 405.

[0049] The ratio of the diameter of the outer lens 404 to the diameter of the inner lens 405 ensures that the light is fully refracted by the inner lens 405, while reserving enough edge area for the outer lens 404 to collect the large-angle divergent light.

[0050] As an improvement, the bottom edge area of the outer lens 404 is provided with an annular reinforcing rib, and the height of the reinforcing rib is 10% to 20% of the total height of the lens. The junction of the inner and outer lenses 404 is provided with a locking part, and the locking angle of the locking part is 60 to 75 degrees.

[0051] The cross section of the reinforcing rib is trapezoidal, the upper base width of the trapezoidal is less than the lower base width, forming an outwardly inclined support surface. The junction of the bottom of the inner and outer lenses 404 is provided with a locking structure including a convex part and a concave part, the cross section of the convex part is dovetail-shaped, and the cross section of the concave part matches the convex part. The locking structure is uniformly distributed along the circumference of the lens, forming an annular locking structure. The outer surface of the outer lens 404 is provided with a periodic array of anti-reflection micro-prism array, and the ridge line direction of the micro-prism is arranged along the radial direction. The bottom of the inner lens 405 is provided with a positioning reference surface, which is in close contact with the top surface of the light emitting device, ensuring that the optical axes of the inner and outer lenses 404 are aligned.

[0052] The diameter of the inner lens 405 ranges from 0.016 mm to 0.024 mm; the diameter of the outer lens 404 ranges from 0.020 mm to 0.030 mm.

[0053] The diameter range of the inner lens 405 and the diameter range of the outer lens 404 match the pixel size. These diameter ranges ensure full coverage of the light rays emitted by a single pixel by the lens and avoid optical cross-talk between adjacent pixels.

[0054] The surface roughness of the inner lens 405 and the outer lens 404 is less than 5 nanometers.

[0055] The outer periphery of the inner lens 405 is provided with a positioning boss, and the inner periphery of the outer lens 404 is provided with an annular groove matched with the positioning boss.

[0056] The outer periphery of the inner lens 405 is provided with a multi-stage positioning structure including an annular positioning boss and a radial positioning column. The top surface of the annular positioning boss is an inclined surface forming a self-alignment structure with the inner wall of the outer lens 404. The radial positioning column is uniformly distributed in the circumferential direction, and the side surface of each positioning column is provided with a guide groove. The inner periphery of the outer lens 404 is provided with an annular groove and a positioning hole matched with the positioning structure, and the cross section of the annular groove is dovetail-shaped for preventing the lens from separating. The inner wall of the positioning hole is provided with a convex rib matched with the guide groove. The contact surface of the two lenses is provided with an anti-slip structure including staggered micro-protrusions and pits forming an interlocking structure.

[0057] The edge region of the inner lens 405 is provided with an annular light ray limiting member including multiple layers of stepped light shielding steps. The surface of each layer of steps is provided with a sawtooth microstructure, and the inclined surface of the sawtooth faces the lens center. When the large-angle scattered light is incident on the sawtooth surface, it will be guided to the light-absorbing layer after multiple reflections. The steps are provided with a refracting surface for refracting part of the large-angle light back to the lens center region.

[0058] The ratio of the height to the diameter of the inner lens 405 ranges from 0.75 to 1.0; and the ratio of the height to the diameter of the outer lens 404 ranges from 0.4 to 0.6.

[0059] The above ratio ensures that the lens has sufficient refractive power and avoids stress problems caused by excessive ratio of the lens.

[0060] The axes of the inner lens 405 and the outer lens 404 coincide. This allows the light rays to be symmetrically distributed when passing through the two lenses.

[0061] The strength half-angle of the lens assembly ranges from 25 degrees to 30 degrees. Within this angle range, the light intensity decay is not more than 50%, ensuring that the light rays can be effectively received by the collimating optical system, while ensuring the uniformity of the brightness of the display device.

[0062] The side wall of the inner lens 405 is provided with a multi-layer refractive structure, including a plurality of concentric annular steps. 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 is provided with a stepped groove matching the step structure, forming a composite refractive interface.

[0063] The spherical cap surface of the inner lens 405 is provided with a concentric annular microstructure, including a periodic annular grating. The grating is divided into multiple regions from the center to the edge, and the grating period gradually increases in each region, and the grating period of adjacent regions changes by equal proportion. In this way, different degrees of diffraction can be produced for light rays of different incident angles, so that the light rays tend to be parallel after transmission. The surface of the outer lens 404 is provided with a stepped refractive structure matching the microstructure of the inner lens 405, and the two structures cooperate to form a composite optical system, which can more effectively control the propagation direction of light.

[0064] The periphery of the lens assembly is provided with an annular stress buffering area, which includes a plurality of corrugated elastic support members uniformly distributed in the circumferential direction. Each elastic support member is composed of three layers of corrugated members, and the wave crests and wave troughs of the corrugated members are arranged alternately, and the adjacent corrugated members are connected by a transition arc surface. The corrugated member can produce a small deformation in the radial and axial directions, thereby relieving the stress caused by thermal expansion. One end of the elastic support member is fixedly connected with the inner lens 405, and the other end is slidably connected with the outer lens 404, forming a flexible support structure.

[0065] The light extraction efficiency of the lens assembly within a field of view angle of ±15 degrees ranges from 23% to 27%.

[0066] The light extraction efficiency of the lens assembly relative to the light extraction efficiency without the lens assembly is improved by 25% to 35%.

[0067] The display device provided in the application realizes effective collimation of light rays through cooperation of the 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 of the two materials (refractive index of silicon nitride is 1.75-1.85, and refractive index of silicon dioxide is 1.45-1.50) forms two refractive interfaces on the light ray propagation path. After the light rays are emitted from the light-emitting layer 402, the light rays first undergo the first refraction of the inner lens 405. Since the inner lens 405 has a higher refractive index, the light rays with large-angle divergence can be refracted into light rays with small angles. Then, the light rays with small angles undergo the second refraction of the outer lens 404, and are further collimated, so that the divergent light rays become more parallel. Since the height of the inner lens 405 is greater than the height of the outer lens 404, and at least a part of the inner lens 405 is sleeved in the outer lens 404, the light rays can be effectively collimated through the two refractions without increasing the total height of the lens, that is, the light extraction efficiency is improved. This avoids the problem of film peeling caused by the increase in the thickness of the silicon dioxide coating in the traditional single-layer lens structure in order to obtain the same light extraction efficiency.

[0068] As shown in Figure 4 The display device provided in the application adopts the double-layer nested structure of the inner lens 405 and the 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 in the application can effectively improve the light extraction efficiency without increasing the total height of the lens, thereby reducing the problem of film peeling caused by the excessive height of the lens and reducing the yield loss.

[0069] Specifically, the display device provided in the application includes a substrate, a driving device layer, a light-emitting device, and a lens assembly. The driving device layer is arranged 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 arranged on the driving device layer, the light-emitting layer 402 is arranged on the bonding metal layer 401, and the transparent conductive layer 403 is arranged on the light-emitting layer 402. The lens assembly includes an inner lens 405 and an outer lens 404. The inner lens 405 and the outer lens 404 are both arranged on the transparent conductive layer 403. At least a part of the inner lens 405 is sleeved in the outer lens 404. The diameter of the outer lens 404 is greater than the diameter of the inner lens 405. The height of the inner lens 405 is greater than the height of the outer lens 404.

[0070] The surface of the inner lens 405 and the outer lens 404 is convex, i.e. a spherical cap. The curvature of the surface of the inner lens 405 ranges from 80 to 130, and the curvature of the surface of the outer lens 404 ranges from 60 to 90. 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 between the refractive index of the two materials is greater than 0.25 and less than 0.4.

[0071] 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 the height of the outer lens 404 and less than 1.5 times the height of the outer lens 404. Within this height range, the stress of the lens can be effectively controlled to avoid cracking or peeling.

[0072] The diameter of the inner lens 405 ranges from 0.016 mm to 0.024 mm, and the diameter of the outer lens 404 ranges from 0.020 mm to 0.030 mm. The diameter of the outer lens 404 is greater than 1.1 times the diameter of the inner lens 405 and less than 1.5 times the diameter of the inner lens 405. This diameter ratio ensures that the lens fully covers the light emitted by a single pixel while avoiding optical crosstalk between adjacent pixels.

[0073] The ratio of the height to the diameter of the inner lens 405 ranges from 0.75 to 1.0, and the ratio of the height to the diameter 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.

[0074] The axes of the inner lens 405 and the outer lens 404 coincide, which ensures that the light is symmetrically distributed when passing through the two lenses. The intensity half-angle of the lens assembly ranges from 25 degrees to 30 degrees, within which the light intensity decays by no more than 50%, ensuring that the light can be effectively received by the subsequent collimating optical system.

[0075] The distance between two adjacent light emitting devices is 4 microns, which, in combination with the lens structure, can achieve a high display resolution.

[0076] To better illustrate the technical effects of the present application, specific embodiments and comparative examples are described in detail below. Table 1 lists the specific parameter configurations of the inner and outer layer lenses 404 in different embodiments and their corresponding optical performance indicators. Among them, code 1 represents the inner layer lens 405, and code 2 represents the outer layer lens 404; the radius refers to the size of 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, so that the lens surface forms a spherical cap shape with a specific curvature; the eccentricity represents the height of the lens, i.e. the distance from the light emitting surface to the top of the lens; H / CD represents the ratio of the lens height H to the lens diameter (CD), wherein the lens diameter (CD) refers to the diameter of the widest part of the lens bottom, i.e. the diameter of the part where the lens contacts the light emitting surface, which is equal to twice the lens radius; the intensity half angle represents the corresponding light emitting angle when the light intensity decreases to 50%.

[0077]

[0078] Table 1

[0079]

[0080] Table 2

[0081] By analyzing the data in Table 1 and Figure 5 the following conclusions can be drawn:

[0082] Comparing the prior art solutions (prior art 1 and 2), it can be seen that the single-layer silicon dioxide lens structure has obvious limitations. Prior art 1 adopts a low height-to-diameter ratio (H / CD = 0.50), which is stable in structure but has an intensity half angle of 34 degrees, but the light extraction effect is not ideal. Prior art 2 reduces the intensity half angle to 24 degrees by increasing the height-to-diameter ratio (H / CD = 1.00), but the silicon dioxide lens is too high and is prone to film peeling problems.

[0083] The double-layer lens structure (embodiments 1 to 5) provided by the present application exhibits better overall performance. In particular, embodiment 5 is the preferred solution: the inner layer silicon nitride lens has a radius of 0.01 mm, a curvature of 125.0, and a height-to-diameter ratio of 0.9375; the outer layer silicon dioxide lens has a radius of 0.012 mm, a curvature of 83.3, and a height-to-diameter ratio of 0.50. This configuration achieves an intensity half angle of 27 degrees while maintaining a moderate overall height, achieving good light collimation effect, i.e. improving the light extraction efficiency.

[0084] As can be seen from the comparison between Example 3 and other examples, the material configuration sequence of the inner and outer layer lenses 404 has a significant impact on the optical performance. When the silicon dioxide is used as the material of the inner layer lens 405 and the silicon nitride is used as the material of the outer layer lens 404 (Example 3), the intensity half angle is increased to 41 degrees, which verifies that the configuration of using the silicon nitride with a higher refractive index as the material of the inner layer lens 405 and the silicon dioxide with a lower refractive index as the material of the outer layer lens 404 is more conducive to light collimation.

[0085] The comparison of the parameters of Example 4 and Example 5 shows that by optimizing the curvature and height-diameter ratio of the lens, the light extraction efficiency can be improved while maintaining the structural stability. Example 4 uses a larger height-diameter ratio (1.875) of the inner layer lens 405, which obtains a smaller intensity half angle (25.5 degrees), but may cause stress problems. In contrast, Example 5 reduces the height-diameter ratio of the inner layer lens 405 to 0.9375, although the intensity half angle is slightly increased (27 degrees), the structure is more stable, and it is a more optimal technical solution.

[0086] As can be seen from the data in Table 2, the preferred solution (Example 5) of the present application has a light extraction efficiency of 25% within a ±15-degree field of view angle range, while the prior art has a light extraction efficiency of only 19% within the same field of view angle range. Through calculation, it is known that the preferred solution of the present application improves the efficiency by 28% compared to the prior art. This improvement in efficiency is due to the double refraction of the double-layer lens structure on the light, which allows more light to be confined within the ±15-degree field of view angle range, thereby improving the receiving efficiency of the subsequent optical system.

[0087] In the display device provided in the embodiments of the present application, when the light is emitted from the light-emitting layer 402, it first undergoes the first refraction of the inner layer lens 405. Since the inner layer lens 405 is made of silicon nitride with a refractive index of 1.75 to 1.85, it can strongly refract the light with a large-angle divergence, significantly reducing the deflection angle. Subsequently, the light enters the outer layer lens 404. Since the outer layer lens 404 is made of silicon dioxide with a refractive index of 1.45 to 1.50, which is lower than that of the inner layer lens 405, it can perform the second refraction on the light that has undergone the first refraction. This double refraction allows the divergent light to form a collimated beam within a ±15-degree field of view angle range, and the intensity half angle of the lens assembly is controlled within a range of 25 to 30 degrees, ensuring that the light intensity decay does not exceed 50%, thereby significantly improving the light extraction efficiency. The height of the inner layer lens 405 is greater than the height of the outer layer lens 404, and this height difference allows the light to pass through two different height refraction interfaces without changing the total height. Compared with the traditional single-layer silicon dioxide lens structure, the double-layer lens structure of the present application can improve the light extraction efficiency without increasing the thickness of the silicon dioxide coating.

[0088] The manufacturing process of the display device provided by the embodiments of the present application comprises:

[0089] forming a driving device layer on the substrate.

[0090] forming a bonding metal layer 401, a light emitting layer 402 and a transparent conductive layer 403 on the driving device layer in sequence.

[0091] forming an inner lens 405 of silicon nitride material on the transparent conductive layer 403.

[0092] forming an outer lens 404 of silicon dioxide material on the periphery of the inner lens 405.

[0093] The inner lens 405 and the outer lens 404 are both formed by patterning the deposited material layer to form a spherical cap surface. This manufacturing method avoids the peeling problem caused by the over-thick silicon dioxide coating in the traditional single-layer high lens structure. By reasonably controlling the material and size ratio of the inner and outer lenses 404, the stress of the entire structure is effectively controlled, thereby improving the product yield.

[0094] The above describes the embodiments of the present application in detail, and the content of the specification should not be understood as limiting the protection scope of the present application.

Claims

1. A display device, characterized in that, include: 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; 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.

2. The display device according to claim 1, characterized in that, 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.

3. The display device according to claim 1, characterized in that, The inner lens is made of silicon nitride, and the outer lens is made of silicon dioxide.

4. The display device according to claim 1, characterized in that, 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.

5. The display device according to claim 4, characterized in that, 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.

6. The display device according to claim 1, characterized in that, 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.

7. The display device according to claim 1, characterized in that, 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.

8. The display device according to claim 1, characterized in that, 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.

9. The display device according to claim 1, characterized in that, The axes of the inner lens and the outer lens coincide.

10. The display device according to claim 1, characterized in that, The intensity half-angle range of the lens assembly is 25 degrees to 30 degrees.

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