Light-emitting device and display device including the same

Abstract

The present application provides a light-emitting device and a display device. The light-emitting device includes: a substrate, on the surface of which a plurality of hemispherical initial LED packages are arranged in an array; a light-turning layer disposed on the initial LED packages, and the surface of the light-turning layer away from the substrate has a flattening effect, and the light-turning layer deflects the light emitted when the initial LED packages work towards the normal side; a light-converting layer disposed on the side of the light-turning layer away from the substrate and parallel to the substrate; wherein, the maximum light-emitting angle of each initial LED package is less than 90°, and the ratio θ of d and h is the included angle between the widest light-emitting ray that can be emitted and the normal line, d is the horizontal distance between the center points of the LEDs included in any two adjacent initial LED packages, h is the shortest distance between the upper surface of the LED included in the initial LED package and the lower surface of the light-converting layer, a is a set value representing the brightness uniformity of the light-emitting device, and 0.6 < a ≤ 1.

Description

Technical Field

[0001] This application relates to the field of optoelectronic technologies, and more particularly, to a light-emitting device and a display device including the same. Background Art

[0002] In many current feasible technologies, mainly through lenses or microstructures, the light-emitting angle of an LED (Light Emitting Diode) is increased to make the light of the entire LED array relatively uniform. However, in actual situations, in order to meet the requirements of brightness and optical uniformity, it is necessary to change the light-emitting angle of the LED, and the LED arrangement and optical films such as diffusion plates and brightness enhancement films act together. For small-pitch or ultra-small-pitch LED arrays such as Mini-LED (Mini Light Emitting Diode) that apply quantum dots, they are often used in small and medium-sized display requirements, and the range of change in the interval between LEDs is limited. At the same time, there are also limitations on the thickness of the overall structure for small and medium-sized displays. Therefore, improving the light shadow problem and light uniformity problem through optical films such as diffusion sheets is also limited.

[0003] Therefore, there is an urgent need for new ways to improve the light-emitting uniformity of LED arrays and alleviate the light shadow problem. Summary of the Invention

[0004] The purpose of this application is to provide a light-emitting device, including: a substrate, on the surface of the substrate, a plurality of hemispherical initial LED packages arranged in an array; a light-turning layer, disposed on the initial LED package, and the surface of the light-turning layer away from the substrate has a flattening effect, and the light-turning layer deflects the light emitted when the initial LED package works towards the normal side; a light-converting layer, disposed on the side of the light-turning layer away from the substrate and parallel to the substrate; wherein, the maximum light-emitting angle θ of each initial LED package is less than 90°, and satisfies The ratio of d to h θ is the angle between the widest light-emitting ray that can be emitted and the normal line, d is the horizontal distance between the centers of the LEDs included in any two adjacent initial LED packages, h is the shortest distance between the upper surface of the LED included in the initial LED package and the lower surface of the light-converting layer, a is a set value representing the brightness uniformity of the light-emitting device, and 0.6 < a ≤ 1.

[0005] Furthermore,

[0006] Furthermore, 0.85 < a ≤ 1.

[0007] Further, the above-mentioned light-emitting device further includes: a first light antireflection layer, which is in contact with and disposed on the above-mentioned initial LED package, conforms to the contour of each initial LED package and extends; the first light antireflection layer is used to allow first light with a wavelength less than a predetermined wavelength emitted by the above-mentioned initial LED package to pass through; the equivalent refractive index of the first light antireflection layer is greater than the equivalent refractive index of the light turning layer; preferably, the above-mentioned predetermined wavelength is 500 nm.

[0008] Further, the first light antireflection layer is further used to reflect second light within a predetermined wavelength band, and the second light is the light that exits from the above-mentioned light conversion layer and reaches the first light antireflection layer; preferably, the range of the above-mentioned predetermined wavelength band is 380 nm - 780 nm.

[0009] Further, the above-mentioned light-emitting device further includes: a second light antireflection layer, which is located on the side of the light conversion layer away from the light turning layer, and the second light antireflection layer is used to allow visible light to pass through and is used to block ultraviolet light; preferably, the second light antireflection layer can transmit light within a wavelength range of 450 nm - 780 nm.

[0010] Further, the second light antireflection layer includes diffusing particles.

[0011] Further, each of the second light antireflection layer, the light conversion layer, the light turning layer, and the first light antireflection layer independently includes one or more layers.

[0012] Further, the equivalent refractive index of the second light antireflection layer, the equivalent refractive index of the light conversion layer, the maximum equivalent refractive index of the light turning layer, and the equivalent refractive index of the first light antireflection layer increase in sequence.

[0013] Further, the above-mentioned light-emitting device further includes: a protective layer, and the protective layer is located on the side of the second light antireflection layer away from the light conversion layer.

[0014] Further, the above-mentioned LED is a micro-LED or a mini-LED.

[0015] Further, the above-mentioned light conversion layer is a quantum dot color film.

[0016] This application also provides a display device, including any of the above-mentioned light-emitting devices.

[0017] Applying the technical solution of the present application, by arranging a light turning layer between the light conversion layer and the initial LED package, the emitted light rays are deflected towards the normal side, and by designing the relationships among the following three: the maximum light emission angle θ of the initial LED package, the distance d between adjacent initial LED packages, the vertical distance h between the initial LED package and the light conversion layer, and setting the brightness uniformity of the light-emitting device and its relationships with d and h, the degree of deflection of the light emitted by the initial LED package towards the normal side is controlled, so as to moderately enhance the light energy in the area between two adjacent initial LED packages and moderately reduce the light energy directly above the initial LED package, solving the light shadow problem of the light-emitting device. Compared with the prior art solution of making the light of the LED array relatively uniform by increasing the light emission angle of the LED, the technical solution of the present application also realizes an improvement in the energy (brightness) distribution uniformity of the light-emitting device with less overall light energy loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings forming a part of this application are used to provide a further understanding of the application. The schematic embodiments and descriptions thereof of the application are used to explain the application and do not constitute an improper limitation to the application. In the drawings:

[0019] Figure 1 shows a schematic structural diagram of a light-emitting device in the prior art;

[0020] Figure 2 shows a schematic structural diagram of a light-emitting device according to an embodiment of the present application;

[0021] Figure 3 shows a schematic diagram of the propagation direction of the widest emitted light rays of a light-emitting device according to an embodiment of the present application;

[0022] Figure 4 shows a schematic structural diagram of a light-emitting device according to an embodiment of the present application;

[0023] Figure 5 shows the optical software simulation result of the light field energy distribution of the light-emitting device according to an embodiment of the present application;

[0024] Figure 6 shows the optical software simulation result of the light field energy distribution of the light-emitting device of Comparative Example 1 of the present application;

[0025] Figure 7 shows the optical software simulation result of the light field energy distribution of the light-emitting device of Comparative Example 2 of the present application.

[0026] Reference numerals:

[0027] 100, Light-emitting device; 10, LED; 11, Substrate; 13, Light conversion layer; 101, First critical light-emitting ray; 102, Second critical light-emitting ray; 200, Light-emitting device; 300, Light-emitting device; 20, Initial LED package; 21, Substrate; 22, Light turning layer; 23, Light conversion layer; 24, First anti-reflection layer; 25, Second anti-reflection layer; 26, Protective layer. Detailed implementation manners

[0028] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0029] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects and do not necessarily have to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to implement the embodiments of the present application described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0030] It will be understood that when an element such as a layer, film, region or substrate is referred to as being "on" another element, it can be directly on the other element or there can be intervening elements therebetween. In contrast, when an element is referred to as being "in contact with" or "directly on" another element, there are no intervening elements.

[0031] Figure 1 An energy distribution model of a light-emitting device 100 with an LED as an initial light source in the prior art is shown, where the intermediate layer between the LED and the light conversion layer 13 is not shown, and the intermediate layer does not include a layer with the same function as the light turning layer. Assuming that only the initial light source A is working, the excitation energy received by the light conversion layer 13 directly above the initial light source A is E1, the excitation energy received by the light conversion layer 13 in the region between the initial light source A and the initial light source B is E3, and the excitation energy received by the light conversion layer 13 directly above the initial light source B is E2. As the distance L between the energy receiving point of the light conversion layer 13 and the initial light source A increases, the excitation energy E continuously decreases, and the excitation energy E ∝ 1 / L 2, therefore, from the center of the initial light source A outwards, the corresponding excitation energy continuously decreases as the optical path increases, that is, E1 > E3 > E2. Taking the light-emitting ray at the rightmost point of the initial light source A as an example, the light-emitting rays between the first critical light-emitting ray 101 and the second critical light-emitting ray 102 are all incident on the light conversion layer 13 directly above another initial light source B. Then when the initial light source A and the initial light source B work simultaneously (for the sake of simplifying the model, the light emission of the initial light sources other than A and B is not considered), the energy directly above the initial light source A is E1 + E2, the energy directly above the initial light source B is E1 + E2, and the energy in the middle region between the initial light source A and the initial light source B is E3 + E3. In actual situations, light shadow phenomena occur above the initial light sources such as mini-LED and micro-LED, that is, E1 + E2 >> 2E3, and the energy (brightness) distribution difference is large, which seriously affects the optical quality of the product.

[0032] In one aspect of the present application, as Figure 2 shown, a light-emitting device 200 is provided, including: a substrate 21, on the surface of the substrate 21, a plurality of hemispherical initial LED packages 20 arranged in an array; a light-turning layer 22, disposed on the initial LED packages 20, and the surface of the light-turning layer 22 away from the substrate 21 has a flattening effect, and the light-turning layer 22 deflects the light emitted when the initial LED packages 20 work towards the normal side; a light conversion layer 23, disposed on the side of the light-turning layer 22 away from the substrate 21 and parallel to the substrate 21; wherein, the maximum light-emitting angle θ of each initial LED package 20 is less than 90°, and satisfies the ratio of d and h θ is the angle between the widest light-emitting ray that can be emitted and the normal line, d is the horizontal distance between the center points of the LEDs included in any two adjacent initial LED packages, h is the shortest distance between the upper surface of the LED included in the initial LED package and the lower surface of the light conversion layer, a is a set value representing the brightness uniformity of the light-emitting device, and 0.6 < a ≤ 1.

[0033] It should be noted that the above-mentioned "normal line" refers to the dotted line that is always perpendicular to the plane where the substrate is located. The above-mentioned "widest light-emitting ray that can be emitted" is defined as the outermost ray of the light beam emitted by the LED included in the initial LED package. The plurality of hemispherical initial LED packages arranged in an array include a plurality of LEDs arranged in an array, and each initial LED package includes one LED. The "upper surface of the LED" refers to the surface of the LED away from the substrate; the "lower surface of the light conversion layer" refers to the surface of the light conversion layer close to the substrate.

[0034] As Figure 1As shown, in a light-emitting device without a light-turning layer, the light-emitting angle of the second critical light-emitting ray 102 is β. When a light-turning layer 22 is provided in the light-emitting device, as Figure 3 shown, the light-emitting ray with a light-emitting angle of β is deflected toward the normal side in the light-turning layer 22, and the intersection point of this light-emitting ray on the lower surface of the light-conversion layer 23 moves to the left, that is, α < β, so that the excitation energy received by the light-conversion layer 23 directly above the initial light source is reduced, and the excitation energy received by the light-conversion layer 23 in the middle region between two adjacent initial light sources is increased, thus compensating for the energy (brightness) distribution difference existing in the light-emitting devices of the prior art and improving the optical quality of the products using the light-emitting devices.

[0035] By providing the above light-emitting device with a light-turning layer between the light-conversion layer and the initial LED package, the present application makes the light-emitting ray deflect toward the normal side, and by designing the relationships among the following three: the maximum light-emitting angle θ of the initial LED package, the distance d between adjacent initial LED packages, the vertical distance h between the initial LED package and the light-conversion layer, and setting the brightness uniformity of the light-emitting device and its relationships with d and h, the degree of deflection of the light emitted by the initial LED package toward the normal side is controlled, so that the light energy in the region between two adjacent initial LED packages is moderately enhanced and the light energy directly above the initial LED package is moderately reduced, solving the light shadow problem of the light-emitting device. Compared with the prior art solution of making the light of the LED array relatively uniform by increasing the light-emitting angle of the LED, the technical solution of the present application also realizes the improvement of the energy (brightness) distribution uniformity of the light-emitting device with less overall light energy loss.

[0036] In some embodiments, the LED can be at least one of a blue light chip, a purple light chip, and an ultraviolet light chip, or can be a high color temperature chip with a color temperature > 10000K.

[0037] In some embodiments, the initial LED package 20 includes a transparent filler provided around the LED for primary encapsulation of the LED to improve its stability and at the same time can play a role in heat insulation.

[0038] In some embodiments,

[0039] In some embodiments, 0.85 < a ≤ 1.

[0040] As Figure 4As shown, in some embodiments, the light-emitting device further includes: a first light antireflection layer 24, which is in contact with and disposed on the initial LED package 20, extending along the contour of each initial LED package 20; the first light antireflection layer 24 is configured to allow first light rays with wavelengths less than a predetermined wavelength emitted by the initial LED package 20 to pass through; the equivalent refractive index of the first light antireflection layer 24 is greater than the equivalent refractive index of the light turning layer 22; preferably, the predetermined wavelength is 500 nm.

[0041] In some embodiments, the first light antireflection layer 24 is further configured to reflect second light rays within a predetermined wavelength band, where the second light rays are the light rays that exit from the light conversion layer 23 and reach the first light antireflection layer 24; preferably, the range of the predetermined wavelength band is 380 nm - 780 nm.

[0042] In some embodiments, the reflectivity of the first light antireflection layer 24 is ≥ 90%, and the reflective surface of the first antireflection layer 24 can be a matte surface for diffuse reflection.

[0043] In some embodiments, the light-emitting device further includes: a second light antireflection layer 25, located on the side of the light conversion layer 23 away from the light turning layer 22, where the second light antireflection layer 25 is configured to allow visible light to pass through and block ultraviolet light; preferably, the second light antireflection layer 25 can transmit light rays within a wavelength range of 450 nm - 780 nm. The second light antireflection layer 25 can effectively prevent the leakage of ultraviolet light, ensuring the light safety of the overall light source. At the same time, it can also effectively reduce the leakage of harmful blue light, reducing high-energy harmful light components from the initial light source and improving the eye health property of the light source.

[0044] In some embodiments, the second light antireflection layer 25 includes diffusing particles. The diffusing particles can further play a role in homogenizing light, further solving the problem of lamp shadows.

[0045] In some embodiments, each of the second light antireflection layer 25, the light conversion layer 23, the light turning layer 22, and the first light antireflection layer 24 independently includes one or more layers. It can also be an optical layer with microstructures.

[0046] In some embodiments, the equivalent refractive index of the second light antireflection layer 25, the equivalent refractive index of the light conversion layer 23, the maximum equivalent refractive index of the light turning layer 22, and the equivalent refractive index of the first light antireflection layer 24 increase in sequence. This is conducive to achieving the convergence of the light emitted after the light conversion layer is irradiated by the excited light, achieving the purpose of increasing brightness.

[0047] In some embodiments, the light-emitting device further includes: a protective layer 26, located on the side of the second light antireflection layer 25 away from the light conversion layer 23. The protective layer 26 is preferably a transparent encapsulation protective layer, having a certain water and oxygen barrier effect, protecting the optical structure and the light conversion layer in the LED array, and extending their service life.

[0048] In some embodiments, the LED is a micro-LED or a mini-LED.

[0049] In some embodiments, the light conversion layer 23 is a quantum dot color film. The quantum dot materials used can be at least two of red quantum dots, green quantum dots, and blue quantum dots. The quantum dot materials have the characteristic of omnidirectional light emission. After the relatively uniform light passes through the light turning layer and then through the quantum dot color film, further light homogenization in the light-emitting surface direction can be achieved.

[0050] In some embodiments, the thickness of the light conversion layer 23 is 20%-30% of the total thickness of the light-emitting device.

[0051] The present application exemplarily provides a method for manufacturing the above-mentioned light-emitting device 200, including the following steps: preparing a substrate, and disposing a plurality of hemispherical initial LED packages arranged in an array on the surface of the substrate; through multi-layer Si 2-x O x or Si3N4 stacking to prepare the light turning layer, where x represents different atomic ratios. Different ratios of Si and O atoms in the light turning layer can be adjusted by reaction conditions and the ratio of reactants, so as to prepare a stacked light turning layer with a stacked structure, or it can also be a stacked structure of different materials; then disposing the light conversion layer material on the upper surface of the planarized light turning layer or attaching a pre-prepared light conversion layer. The preparation methods of each optical functional layer can be realized by various suitable processes in the prior art, and will not be elaborated in the present application.

[0052] Another aspect of the present application provides a display device, including any of the above-mentioned light-emitting devices. Since the light-emitting device has good light-emitting uniformity, the display device using it also has good brightness uniformity. The above-mentioned display device can be a small and medium-sized display terminal such as a laptop computer, a monitor, a mobile phone, etc., or a large-sized display terminal such as a television.

[0053] The beneficial effects of the present application will be further described below in conjunction with embodiments and comparative examples.

[0054] A light-emitting device with two adjacent LED lamp beads is constructed through an optical simulation software. The LED lamp bead emits light with a wavelength of 470 nm, a full width at half maximum of 18 nm, a lamp bead length of 3.5 mm, and a width of 2.8 mm (referring to the 2835 specification). A light field energy distribution monitor is disposed directly above the light-emitting device. Based on the above light-emitting device, the energy field distribution under different structures (different light deflection angle results) is obtained as Figures 5 - 7 shown. The numbers 0-8 in the figure represent different magnitudes of energy, and different colors correspond to the Figures 5 - 7 distribution of different energy fields as the number increases from small to large. The energy distributions of the embodiments and Comparative Examples 1 and 2 are monitored through the light field energy distribution monitor.

[0055] Example

[0056] Based on Figure 2 For the corresponding light-emitting device 200, with the requirement that the brightness uniformity a = 0.8, it can be calculated that d / h ≤ 2.16, 47.2 < θ < 65.2. Thus, θ is set to 65°, the lamp bead spacing d is set to 7 mm, and the shortest distance h between the upper surface of the LED lamp bead and the lower surface of the light conversion layer 23 is 3.3 mm, so that the emitted light rays are deflected and the relative angle is reduced, and the corresponding energy distribution is as Figure 5 shown

[0057] The light rays are deflected in the light turning layer 22, thereby controlling the degree of deflection of the light rays emitted by the initial LED package towards the normal side, so that the light energy in the region between two adjacent initial LED packages is moderately enhanced and the light energy directly above the initial LED package is moderately reduced (energy level 8 compared to energy level 7), and the overall energy distribution is uniform. At the same time, from the simulation results, the light emission angle is relatively reduced through the light ray deflection, the optical path between the light source and the quantum dot layer is reduced, the energy loss is reduced, and the overall energy distribution is relatively strong (energy level 7).

[0058] Comparative Example 1

[0059] Based on Figure 1 For the corresponding light-emitting device, no light turning layer or other layer that can deflect the emitted light rays is provided. The simulation results of the corresponding energy field distribution are shown in Figure 6 , and it decreases sequentially outward with the LED lamp bead as the energy center; at the same time, in the region between two LED lamp beads, the light energy decreases as the distance from the light source increases, and obvious energy differences are formed between two light sources and above two light sources (energy level 8 compared to energy level 2), corresponding to the problem of lamp shadow in the region with higher energy.

[0060] Comparative Example 2

[0061] For a light-emitting device based on a conventional prism structure, that is, between Figure 1 the initial light source A (and the initial light source B) and the light conversion layer 13, a prism structure is provided to expand the angle of the light rays emitted by the light source. The corresponding energy field distribution is as Figure 7 shown. The energy distribution above the light source (LED lamp bead) and the energy distribution between two light sources also change: as the light emission angle of the light source increases, the central energy diffuses to the surroundings above the light source, resulting in a relatively enhanced energy distribution, reducing the energy difference between two light sources and above the light source (energy level 8 compared to energy level 5), and the overall energy distribution is uniform (energy level 6).

[0062] Although corresponding to Figure 5And Figure 7 Both of the two methods can change the light propagation direction, so as to realize the relative homogenization of the light energy distribution in different regions. Corresponding to the increased angle, the strong energy near the light source will be dispersed to the weak energy region to achieve light homogenization, which is beneficial to solve the corresponding light shadow problem. However, when the light emission angle increases, the optical path increases and the corresponding energy loss increases. Therefore, compared with the prior art technical solution of making the light of the entire LED array relatively uniform by increasing the light emission angle of the LED, the technical solution of the present application also realizes the improvement of the energy (brightness) distribution uniformity of the light-emitting device under the condition of relatively small overall light energy loss.

[0063] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A light-emitting device, characterized in that, Comprising: A substrate, on the surface of which a plurality of hemispherical initial LED packages are arranged in an array; A light turning layer, disposed on the initial LED package, and the surface of the light turning layer away from the substrate has a flattening effect, and the light turning layer deflects the light emitted when the initial LED package operates towards the normal side; A light conversion layer, disposed on the side of the light turning layer away from the substrate and parallel to the substrate; Among them, the maximum light-emitting angle θ of each of the initial LED packages is less than 90°, and it satisfies The ratio of d to h θ is the angle between the widest light-emitting ray that can be emitted and the normal line, d is the horizontal distance between the center points of the LEDs included in any two adjacent initial LED packages, h is the shortest distance between the upper surface of the LED included in the initial LED package and the lower surface of the light conversion layer, a is a set value representing the brightness uniformity of the light-emitting device, and 0.6 < a ≤ 1.

2. The light-emitting device according to claim 1, characterized in that, 3. The light-emitting device according to claim 1, characterized in that, 0.85＜a≤1。 4. The light-emitting device according to claim 1, characterized in that, The light emitting device further comprises: A first anti-reflection layer, in contact with and disposed on the initial LED package, conforming to the contour of each initial LED package and extending; the first anti-reflection layer is used to allow first light with a wavelength less than a predetermined wavelength emitted by the initial LED package to pass through; the equivalent refractive index of the first anti-reflection layer is greater than the equivalent refractive index of the light turning layer.

5. The light-emitting device according to claim 4, wherein The first anti-reflection layer is further used to reflect second light within a predetermined wavelength band, and the second light is the light emitted from the light conversion layer and reaching the first anti-reflection layer.

6. The light-emitting device according to claim 5, characterized in that, The range of the predetermined wavelength band is 380nm - 780nm.

7. The light-emitting device according to claim 4, characterized in that, The light emitting device further comprises: A second anti-reflection layer, located on the side of the light conversion layer away from the light turning layer, the second anti-reflection layer is used to allow visible light to pass through and to block ultraviolet light from passing through.

8. The light-emitting device according to claim 7, wherein, The second anti-reflection layer can transmit light within a wavelength range of 450nm - 780nm.

9. The light-emitting device according to claim 7, wherein, The second anti-reflection layer includes diffusing particles.

10. The light-emitting device according to claim 7, characterized in that, The second anti-reflection layer, the light conversion layer, the light turning layer, and the first anti-reflection layer each independently include one or more layers.

11. The light-emitting device according to claim 7, wherein The equivalent refractive index of the second anti-reflection layer, the equivalent refractive index of the light conversion layer, the maximum equivalent refractive index of the light turning layer, and the equivalent refractive index of the first anti-reflection layer increase in sequence.

12. The light-emitting device according to claim 7, wherein, The light emitting device further comprises: A protective layer, located on the side of the second anti-reflection layer away from the light conversion layer.

13. The light-emitting device according to any one of claims 1-11, characterized in that, The LED is a micro-LED or a mini-LED.

14. The light-emitting device according to any one of claims 1-11, characterized in that, The light conversion layer is a quantum dot color film.

15. A display device, characterized in that, A light emitting device according to any one of claims 1 to 14.

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