Light emitting device and applications thereof

Abstract

The application provides a light-emitting device and application thereof. The unique fluorescent layer design of the light-emitting device can improve the contrast ratio and color temperature stability of the light-emitting device, especially when the LED layer is in a large-power blue light scene, the light-emitting device can still achieve high color temperature stability and high contrast ratio, and can be applied to pixelized vehicle lamps and other LED display scenes.

Description

Technical Field

[0001] This application relates to the field of light-emitting device technology, specifically to light-emitting devices and their applications. Background Technology

[0002] LED light-emitting devices are widely welcomed in the market due to their high brightness and vibrant colors. In LED light-emitting devices, a phosphor layer is often deposited on the surface of the LED layer. This phosphor layer converts the blue light emitted by the LED pixel unit into white light or other colors. The performance of the phosphor layer has a significant impact on the optical performance of the LED light-emitting device, such as luminous efficacy, color temperature, and color rendering index. In some applications of LED light-emitting devices, such as pixelated automotive lights, there are high requirements for color temperature stability and contrast. The thickness of the phosphor layer significantly affects these properties of pixelated automotive lights: contrast decreases as the phosphor layer thickness increases, while color temperature stability decreases as the phosphor layer thickness decreases. Furthermore, in related technologies, it is difficult to simultaneously achieve high contrast and high color temperature stability by adjusting the phosphor layer thickness. Summary of the Invention

[0003] This application provides a light-emitting device and its application. The unique phosphor layer design of the light-emitting device can simultaneously improve the contrast and color temperature stability of the light-emitting device. In particular, when the LED layer is in a high-power blue light scenario, it can still achieve high color temperature stability and high contrast. It can be applied to LED display scenarios such as pixelated car lights.

[0004] The first aspect of this application provides a light-emitting device, including:

[0005] An LED layer and a phosphor layer are stacked along a first direction;

[0006] The LED layer includes multiple pixels arranged in an array, and the circumcircle diameter of the surface of each pixel near the fluorescent layer is D1;

[0007] The fluorescent layer includes a matrix and a plurality of fluorescent particles and a plurality of scattering particles dispersed in the matrix. The fluorescent particles are used to convert light of a first wavelength into light of a second wavelength. The D50 particle size of the fluorescent particles is D2, and the D50 particle size of the scattering particles is D3, where D2>D3.

[0008] In any cross section along the first direction, the total cross-sectional area of ​​the plurality of fluorescent particles in the region within the orthogonal projection range of any pixel of the fluorescent layer is ≥50%, and the total cross-sectional area of ​​the plurality of scattering particles is ≤5%.

[0009] The size of the fluorescent layer in the first direction is H; wherein, H≤D1 or H≤60μm.

[0010] The fluorescent layer contains both fluorescent and scattering particles. By controlling the particle size relationship and cross-sectional area ratio of the fluorescent and scattering particles within a specific range, and ensuring H≤D1, the scattering particles are easily dispersed among the fluorescent particles. This not only reflects a portion of the light emitted from the pixel, altering the emission direction of this light and reducing the risk of light from the corresponding pixel escaping from neighboring pixels, but also reduces the risk of optical crosstalk between pixels. Furthermore, the scattering effect of the scattering particles allows the same beam of light emitted from the same light source to excite the phosphor multiple times, thereby increasing the conversion rate of the first wavelength light to the second wavelength light. It also increases the probability that the second wavelength light and the unconverted first wavelength light recombine within the fluorescent layer and are emitted from the corresponding light-emitting surface. When the first wavelength is blue light and the second wavelength is yellow light, it can effectively improve the stability and uniformity of the color temperature and the contrast of the light-emitting device.

[0011] In some embodiments of this application, in any cross-section along the first direction, the total cross-sectional area of ​​the plurality of fluorescent particles in the region of any pixel of the fluorescent layer within the orthogonal projection range of the fluorescent layer accounts for 50%-90%, and the total cross-sectional area of ​​the plurality of scattering particles accounts for 0.01%-5%. This facilitates the conversion of a portion of the first wavelength light emitted by the pixel into second wavelength light within its corresponding fluorescent layer region, and the resulting second wavelength light is combined with the first wavelength light before being emitted from the region corresponding to the pixel, reducing the probability of direct emission of the first wavelength light and thus improving the luminous quality of the light-emitting device.

[0012] In some embodiments of this application, D1 and D2 satisfy: D2 ≤ 1 / 4D1. This facilitates thinning of the fluorescent layer and improves the matching degree between the size of the fluorescent particles and the pixel size, reducing the risk of impaired color temperature stability due to insufficient number of fluorescent particles arranged along the first direction in the fluorescent layer.

[0013] In some embodiments of this application, D2 satisfies: D2≤15μm. This facilitates synergy between fluorescent particles and scattering particles, and the fluorescent particles have the function of converting blue light into yellow light with a high conversion rate.

[0014] In some embodiments of this application, D3 satisfies: 10nm ≤ D3 ≤ 10μm. This effectively reduces the risk of a significant increase or decrease in the number of scattering particles due to a decrease or increase in the particle size, thus affecting the scattering effect and further optimizing the luminous quality of the light-emitting device.

[0015] In some embodiments of this application, in any cross-section along the first direction, the number of scattering particles in the region of the orthogonal projection of any pixel of the fluorescent layer on the fluorescent layer is ≥ 5 times the number of fluorescent particles. This makes it easier for the scattering particles to disperse in the gaps between the fluorescent particles, effectively reducing the risk of light of the first wavelength emanating directly from the light-emitting surface due to the lack of scattering particles between the fluorescent particles; furthermore, the relative numbers of the two are more suitable, resulting in a better synergistic effect between the scattering particles and the fluorescent particles, which is more conducive to improving the luminous quality of the light-emitting device.

[0016] In some embodiments of this application, the number of fluorescent particles in the fluorescent layer in the first direction is ≤D1 / D2. This facilitates thinning of the fluorescent layer while improving contrast.

[0017] In some embodiments of this application, H and D2 satisfy: |H-3D2|≤40μm. This facilitates the staggered arrangement of fluorescent particles in the first direction, making it easier for light to propagate between the fluorescent and scattering particles through the matrix, thereby improving the luminescence quality.

[0018] In some embodiments of this application, in any cross-section along the first direction, the region within the orthographic projection of any pixel of the fluorescent layer on the fluorescent layer includes at least four first regions perpendicular to the first direction. The orthographic projections of the first regions on the LED layer do not overlap, and each first region includes at least one fluorescent particle. This reduces the number of fluorescent particles perpendicular to the first direction in the fluorescent layer while ensuring high conversion efficiency in converting light of the first wavelength to light of the second wavelength, thereby reducing the risk of inter-pixel crosstalk.

[0019] In some embodiments of this application, in any cross-section along the first direction, the number of scattering particles in any region with a width of 10D3 perpendicular to the first direction for any pixel of the fluorescent layer is N; the number of scattering particles in any region with a width of 10D3 parallel to the first direction is M, where M ≥ 2N, and both M and N are positive integers. Thus, in the light-emitting device provided in the embodiments of this application, the lateral propagation of light within the fluorescent layer can be more effectively suppressed, reducing the probability of light emanating from the regions corresponding to other pixels, thereby improving contrast.

[0020] In some embodiments of this application, D1 satisfies: D1≤300μm.

[0021] In some embodiments of this application, the plurality of scattering particles are uniformly distributed in the fluorescent layer. This makes the fluorescent layer easier to fabricate, and, with other parameters being equal, the uniformly dispersed scattering particles are more conducive to increasing the probability of light emitted from the pixel colliding with the fluorescent particles, thus improving color temperature stability and uniformity, and also enhancing contrast.

[0022] In some embodiments of this application, the number of scattering particles gradually decreases along the direction from the LED layer to the phosphor layer. This improves the light extraction efficiency of the wavelength-converted light while maintaining high color temperature uniformity and stability.

[0023] In some embodiments of this application, the absorption rate of the scattering particles for the first wavelength light and the second wavelength light is ≤3%. This reduces the loss of the first wavelength light emitted by the pixel and the second wavelength light obtained after conversion by the fluorescent particles, thereby improving the light extraction efficiency.

[0024] In some embodiments of this application, the first wavelength is 430nm-480nm, and the second wavelength is 480nm-750nm. That is, the light of the first wavelength is blue light, and the light of the second wavelength is blue light.

[0025] In some embodiments of this application, the refractive index of the scattering particles in the fluorescent layer is greater than the refractive index of the matrix in the visible light band. This improves the optical scattering effect at the interface between the scattering particles and the matrix.

[0026] In some embodiments of this application, the refractive index of the fluorescent particles in the visible light band is greater than the refractive index of the matrix in the visible light band. This improves the optical scattering effect at the interface between the fluorescent particles and the matrix.

[0027] In some embodiments of this application, the material of the scattering particles includes one or more of zirconium oxide, titanium oxide, aluminum oxide, and silicon dioxide;

[0028] And / or, the fluorescent particles are made of one or more of cerium-doped yttrium aluminum garnet and quantum dots;

[0029] And / or, the matrix material includes resin.

[0030] In some embodiments of this application, the LED layer of the light-emitting device is a Micro-LED layer, which can provide high resolution and high contrast display effects, as well as vivid colors, and has low power consumption and long service life.

[0031] The second aspect of this application provides a lamp, including the light-emitting device provided in the first aspect of this application.

[0032] In some embodiments of this application, the lighting fixture includes pixelated vehicle lights. Due to the presence of the light-emitting device provided in the embodiments of this application, the pixelated vehicle lights can achieve both high contrast, high color temperature stability, and high color temperature uniformity, meeting the needs of daily driving and nighttime driving.

[0033] A third aspect of this application provides a vehicle that includes the lamps provided in the second aspect of this application, or the light-emitting device provided in the first aspect of this application.

[0034] In some embodiments of this application, the vehicle includes the pixelated headlights provided in the embodiments of this application. Due to the use of the pixelated headlights provided in the embodiments of this application, the vehicle has stronger market competitiveness. In some embodiments of this application, the aforementioned vehicle includes, but is not limited to, new energy vehicles, gasoline-powered vehicles, and rail trains.

[0035] A fourth aspect of this application provides a terminal device including a display module. The display module includes a display panel and a light-emitting device provided in the first aspect of this application, wherein the light-emitting device is stacked with the display panel. Due to the use of the light-emitting device provided in this application, this terminal device has strong market competitiveness and a promising market prospect. Attached Figure Description

[0036] Figure 1 This is a simplified schematic diagram of the structure of a light-emitting device according to an embodiment of this application, with its cross-section parallel to the first direction.

[0037] Figure 2 This is a top view of the LED layer of a light-emitting device provided in an embodiment of this application, specifically a top view from the fluorescent layer toward the LED layer;

[0038] Figure 3 This is a simplified schematic diagram of the structure of a light-emitting device in another embodiment of this application, with its cross-section parallel to the first direction.

[0039] Figure 4 This is a simplified schematic diagram of the structure of a light-emitting device in a cross-section parallel to the first direction, according to another embodiment of this application.

[0040] Figure 5 This is a simplified schematic diagram of the structure of a light-emitting device in a cross-section parallel to the first direction, according to another embodiment of this application.

[0041] Figure 6 This is a simplified schematic diagram of the structure of a light-emitting device in a cross-section parallel to the first direction, according to another embodiment of this application.

[0042] Explanation of icon numbers:

[0043] 1-Light-emitting devices;

[0044] 10-LED layer;

[0045] 101 pixels;

[0046] 20-fluorescent layer;

[0047] 201-Matrix;

[0048] 202-Fluorescent particles;

[0049] 203-scattering particles;

[0050] 21-First Zone;

[0051] 30-Base. Detailed Implementation

[0052] Light-emitting diodes (LEDs), especially Micro-LEDs, are considered one of the mainstream next-generation display technologies due to their excellent display characteristics. In LED-type light-emitting devices that require white light, a phosphor layer is often placed on the surface of the LED layer to convert the blue light emitted by the LED into white light or other colors. The performance of the phosphor layer has a significant impact on the optical performance of LED-type light-emitting devices, such as luminous efficacy, color temperature, and color rendering index. In related technologies, the phosphor layer is generally composed of a matrix and fluorescent particles dispersed in the matrix. In some applications, such as pixelated automotive lights, it is necessary to exhibit sufficiently high contrast, color temperature stability, and color temperature uniformity. The LED layer generally includes multiple pixels arranged in an array. Optical crosstalk between adjacent pixels can significantly affect the contrast of the light-emitting device. Specifically, since the fluorescent particles not only have a wavelength conversion effect on the blue light emitted by the pixels but also scatter blue light, the blue light scattered by the fluorescent particles is emitted in all directions. Excessive lateral propagation of light between fluorescent particles (lateral refers to parallel or approximately parallel to the pixel arrangement direction) will eventually result in light exiting from the light-emitting surface corresponding to the adjacent pixel, leading to inter-pixel crosstalk and severely reducing contrast. Reducing inter-pixel crosstalk is an effective way to improve contrast. Reducing the thickness of the phosphor layer to decrease the number of vertically aligned phosphor particles can reduce light crosstalk, but this leads to more unconverted blue light being emitted directly, causing instability in the color temperature of the white light emitted by the light-emitting device. Furthermore, this instability worsens with increasing blue light power. Currently, related technologies cannot achieve simultaneous improvement in color temperature stability and contrast through simple adjustments to the thickness of the phosphor layer or the number of vertically aligned phosphor particles, thus failing to meet the application requirements of pixelated automotive lights.

[0053] Please see Figure 1 To address the aforementioned technical problems, this application provides a light-emitting device 1, comprising:

[0054] An LED layer 10 and a phosphor layer 20 are stacked along a first direction;

[0055] The LED layer 10 includes a plurality of pixels 101 arranged in an array, and the outer circle diameter of the surface of the pixel 101 near the phosphor layer 20 is D1.

[0056] The fluorescent layer 20 includes a matrix 201 and a plurality of fluorescent particles 202 and a plurality of scattering particles 203 dispersed in the matrix 201. The fluorescent particles 202 are used to convert light of a first wavelength into light of a second wavelength. The D50 particle size of the fluorescent particles 202 is D2, and the D50 particle size of the scattering particles 203 is D3, where D2>D3.

[0057] Please see Figure 1 , Figure 1 This is a simplified schematic diagram of the structure of the light-emitting device 1 in this embodiment of the application, with its cross-section parallel to the first direction. Figure 1 The light emission direction is marked in the middle and is parallel to the first direction; the surface of the LED layer 10 facing the phosphor layer 20 is marked as the emitting surface, and the surface of the phosphor layer 20 away from the LED layer 10 is marked as the emitting surface. Specifically, in any cross section along the first direction, the total cross-sectional area of ​​multiple fluorescent particles 202 in the region of any pixel 101 of the phosphor layer 20 within the orthogonal projection range on the phosphor layer 20 is ≥50%, and the total cross-sectional area of ​​multiple scattering particles 203 is ≤5% in any cross section; specifically, taking the shape of the surface of pixel 101 near the phosphor layer 20 as a square as an example, the region of any pixel 101 of the phosphor layer 20 within the orthogonal projection range on the phosphor layer 20 refers to "a cube or cuboid with the orthogonal projection of the square on the phosphor layer as the base, and the height of the cube or cuboid is the dimension of the phosphor layer in the first direction (i.e., the thickness of the phosphor layer)", and any cross section along the first direction refers to the cross section obtained by cutting the cube or cuboid with any plane parallel to the first direction. The above example only uses the shape of the surface of pixel 101 near the fluorescent layer 20 as a square. When the shape of the surface of pixel 101 near the fluorescent layer 20 is other, the above principle can be applied by analogy, which will not be elaborated here.

[0058] The size of the fluorescent layer 20 in the first direction is H; wherein, H≤D1 or H≤60μm.

[0059] Please see Figure 2 In this embodiment, the circumcircle diameter of the surface of pixel 101 near the phosphor layer 20 refers to the circumcircle diameter of pixel 101 obtained by etching the LED layer 10 in the reverse direction from the phosphor layer 20 towards the LED layer 10. The shape and size of the surfaces of multiple pixels 101 of the LED layer 10 near the phosphor layer 20 can be the same or different; when the shape and / or size of multiple pixels 101 of the LED layer 10 are different, the above-mentioned D1 is the average value of the circumcircle diameter of the surface of each pixel 101 near the phosphor layer 20.

[0060] In some embodiments of this application, the pixels 101 in the LED layer 10 have the same size. In some embodiments of this application, the pixels 101 in the LED layer 10 have the same shape. In some specific embodiments, the pixels 101 in the LED layer 10 have both the same size and shape. Thus, the LED layer 10 is easy to fabricate, and the luminous efficacy is more uniform throughout the LED layer 10, which is beneficial for applications.

[0061] In this embodiment, the shape of the surface of pixel 101 near the phosphor layer 20 includes, but is not limited to, polygons such as squares, rectangles, triangles, and hexagons, as well as circles and ellipses; this application does not limit this, and the shape of pixel 101 can be any shape applicable to LED pixels within the field. It should be noted that when the shape of the surface of pixel 101 near the phosphor layer 20 is circular, the circumscribed circle diameter D1 is the diameter of the circle itself; when the shape of the surface of pixel 101 near the phosphor layer 20 is elliptical, the circumscribed circle diameter D1 is the major axis of the ellipse.

[0062] In this embodiment of the application, in the LED layer 10, the multiple pixels 101 can be arranged closely together or spaced apart, and this application does not limit this.

[0063] The fluorescent particles 202 can convert light of a first wavelength into light of a second wavelength. Both the first and second wavelengths are range values, and they are different from each other. The following explanation uses an example of a first wavelength of 430nm-480nm (blue light) and a second wavelength of 480nm-750nm (yellow light) to illustrate the effect of the light-emitting device 1 in this embodiment:

[0064] In this embodiment, fluorescent particles 202 and scattering particles 203 are simultaneously dispersed in the fluorescent layer 20. By adjusting the particle size relationship and cross-sectional area ratio of the fluorescent particles 202 and scattering particles 203 within a specific range and controlling H≤D1, the scattering particles 203 are easily dispersed among the fluorescent particles 202. This not only reflects part of the light emitted from the pixels 101 of the LED layer 10, changing the emission direction of this part of the light, and reducing the risk of the light emitted from the corresponding pixel 101 escaping from the light-emitting surface corresponding to the neighboring pixel 101, but also reduces the risk of optical crosstalk between pixels 101. The scattering effect of the scattering particles 203 can also cause the same beam of light emitted from the same light source to excite the phosphor multiple times, thereby increasing the conversion rate of blue light (i.e., light of the first wavelength) to yellow light (i.e., light of the second wavelength), and increasing the probability that yellow light and unconverted blue light recombine into white light in the fluorescent layer 20 and are emitted from the corresponding light-emitting surface, thereby improving the stability and uniformity of the color temperature and the contrast of the light-emitting device 1.

[0065] In addition, by limiting the particle size relationship and cross-sectional area ratio of fluorescent particles 202 and scattering particles 203 in each region, when H>D1 and H≤60μm are controlled, the color temperature stability and contrast of the light-emitting device 1 can also be improved to a certain extent, meeting the application requirements of scenarios such as pixel-101 ​​automotive lights.

[0066] In this embodiment of the application, the total percentage of the cross-sectional area of ​​multiple fluorescent particles 202 in any cross section along the first direction of any pixel 101 of the fluorescent layer 20 within the orthogonal projection range of the fluorescent layer 20 can be, for example, 50%, 52%, 55%, 58%, 60%, 62%, 65%, 68%, 70%, 72%, 75%, 78%, 80%, 82%, 85%, 88%, 90%, 92%, etc.

[0067] In this embodiment of the application, the total percentage of the cross-sectional area of ​​multiple scattering particles 203 in any cross-section along the first direction of any pixel 101 of the fluorescent layer 20 within the orthogonal projection range of the fluorescent layer 20 can be, for example, 0.01%, 0.05%, 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 1.9%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, 5%, etc.

[0068] In some embodiments of this application, in any cross-section along the first direction within the orthogonal projection range of any pixel 101 of the fluorescent layer 20, the total cross-sectional area of ​​multiple fluorescent particles 202 accounts for 50%-90%, the total cross-sectional area of ​​multiple scattering particles 203 accounts for 0.01%-5%, and the total cross-sectional area of ​​the matrix 201 accounts for 5%-49.99%. In some specific embodiments, the total cross-sectional area of ​​multiple fluorescent particles 202 accounts for 50%-90%, the total cross-sectional area of ​​multiple scattering particles 203 accounts for 0.01%-2%, and the total cross-sectional area of ​​the matrix 201 accounts for 49.99%-8%. In this way, it is more conducive to converting some of the blue light emitted by pixel 101 into yellow light in the corresponding phosphor layer 20 area and then combining it with the unconverted blue light before emitting it from the corresponding light-emitting surface. This reduces the probability of blue light being emitted directly from the light-emitting surface, which is more conducive to improving the light emission quality of the light-emitting device 1, including higher contrast and higher color temperature stability. Its phosphor layer 20 has better intensity, which is easy to apply to the light-emitting device 1.

[0069] In this embodiment, the LED layer 10 includes an array of multiple pixels 101, which can emit light of different wavelengths; for example, the light emitted by the pixel 101 can be blue light, yellow light, green light, red light, etc., but is not limited thereto. In some embodiments of this application, the multiple pixels 101 of the LED layer 10 include multiple pixels 101 that emit blue light; specifically, the wavelength of the blue light is 400nm-460nm.

[0070] In some embodiments of this application, the first wavelength is 430nm-480nm, and the second wavelength is 480nm-750nm. That is, the fluorescent particle 202 can be excited by blue light and convert the blue light into yellow light for emission. It should be noted that 430nm-480nm is a wide wavelength range for blue light, and 480nm-750nm is a wide wavelength range for yellow light. Furthermore, the wavelength used to excite the fluorescent particle is different from the wavelength converted after the fluorescent particle is excited. It is understood that some of the blue light emitted by the LED pixel 101 is not converted by the fluorescent particle 202, while some of the blue light emitted by the LED pixel 101 is converted into yellow light by the fluorescent particle 202. The converted yellow light is then combined with the aforementioned blue light to form white light. Thus, the fluorescent layer 20 can convert the blue light emitted by the LED layer 10 pixel 101 into white light, and it has high color temperature stability and high contrast, providing good brightness and visual comfort. When applied in automotive lighting scenarios, it is suitable for both nighttime and daily driving.

[0071] In this embodiment, the light-emitting device 1 may be, for example, a Mini-LED device or a Micro-LED device, but is not limited thereto. In some embodiments, D1 ≤ 300 μm, and may be, for example, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, 220 μm, 250 μm, 280 μm, 300 μm, etc. In some embodiments, D1 < 60 μm, for example, 20 μm-50 μm.

[0072] In some embodiments of this application, the circumscribed circle diameter D1 of the side surface of pixel 101 closest to the fluorescent layer 20 is ≤300μm, and the thickness H of the fluorescent layer 20 is ≤60μm. Specifically, the thickness H of the fluorescent layer 20 can be, for example, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 8μm, 10μm, 12μm, 15μm, 18μm, 20μm, 22μm, 25μm, 28μm, 30μm, 32μm, 35μm, 38μm, 40μm, 42μm, 45μm, 48μm, 50μm, 52μm, 55μm, 58μm, 60μm, etc.

[0073] In this embodiment of the application, the thickness H of the fluorescent layer 20 can be, for example, 0.98D1, 0.95D1, 0.92D1, 0.9D1, 0.88D1, 0.85D1, 0.8D1, 0.78D1, 0.75D1, 0.72D1, 0.7D1, 0.68D1, 0.65D1, 0.62D1, 0.6D1, 0.58D1, 0.55D1, 0.52D1, 0.5D1, 0.48D1, 0.45D1, 0.42D1, 0.4D1, 0.38D1, 0.35D1, 0.32D1, 0.3D1, 0.28D1, 0.25D1, 0.22D1, 0.2D1, etc., but is not limited to these. In some specific embodiments, the thickness H of the phosphor layer 20 is 1 / 10D1 to 1 / 2 D1. This is more conducive to improving the color temperature stability, color temperature uniformity, and contrast of the light-emitting device at high color temperatures.

[0074] In some embodiments of this application, the circumscribed circle diameter D1 of the side surface of pixel 101 near the fluorescent layer 20 is less than 60 μm, and the thickness H of the fluorescent layer 20 is less than or equal to D1.

[0075] In this embodiment, D50 particle size refers to the particle size corresponding to a cumulative particle size distribution percentage of 50%.

[0076] In some embodiments of this application, D2 ≤ 1 / 4D1, that is, the D50 particle size of the fluorescent particles 202 ≤ 1 / 4D1. This facilitates the thinning of the fluorescent layer 20, and the size of the fluorescent particles 202 matches the size of the pixel 101 more closely. It also makes it easier to control the number of fluorescent particles 202 arranged in the light-emitting direction within the region of the fluorescent layer 20 corresponding to any pixel 101 within a suitable range, reducing the risk of color temperature instability due to insufficient number of fluorescent particles 202 in the fluorescent layer 20. In some specific embodiments of this application, D2 ≤ 15μm; that is, the D50 particle size of the fluorescent particles 202 ≤ 15μm. This further facilitates the synergy between the fluorescent particles 202 and the scattering particles 203, and the fluorescent particles 202 have the function of converting blue light into yellow light with a high conversion rate. Specifically, the particle size of the fluorescent particles 202 can be, for example, 50 nm, 100 nm, 200 nm, 300 nm, 500 nm, 800 nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, etc. In the embodiments of this application, the D50 particle size of the fluorescent particles 202 can be tested by scanning electron microscopy (SEM).

[0077] In some embodiments of the present application, 10nm≤D3≤10μm. It can be understood that since the proportion of the cross-sectional area of the scattering particles 203 in the specific region is within a specific range, further controlling the D50 particle size of D3 within the range of 10nm to 10μm can effectively reduce the risk that the significant increase or decrease in the number of scattering particles 203 caused by the decrease or increase in the particle size of the scattering particles 203 affects the scattering effect, thereby further facilitating the optimization of the light-emitting quality of the light-emitting device 1. Specifically, the D50 particle size (D3) of the scattering particles 203 can be, for example, 10nm, 20nm, 30nm, 50nm, 80nm, 100nm, 120nm, 150nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, etc. In the examples of the present application, the D50 particle size of the scattering particles 203 can be tested by SEM.

[0078] In some specific embodiments, the scattering particles 203 are submicron particles; for example, 10nm≤D3<1μm. In this way, it is more conducive to the exertion of the scattering effect of the scattering particles 203.

[0079] In some specific embodiments of the present application, 10nm≤D3≤10μm, and D3<D2≤15μm. In some specific embodiments, 10nm≤D3<1μm, and D3<D2≤15μm. In this way, it is beneficial to control the quantity ratio of the fluorescent particles 202 to the scattering particles 203 in the fluorescent layer 20 within a more suitable range, optimize the relative concentration of the distribution of the fluorescent particles 202 and the scattering particles 203 in the fluorescent layer 20, and further facilitate the simultaneous improvement of the color temperature stability and contrast of the light-emitting device 1.

[0080] In some embodiments of this application, in any region of any pixel 101 of the fluorescent layer 20 within the orthographic projection range of the fluorescent layer 20, along any cross section in the first direction, the number of scattering particles 203 is ≥ 5 times the number of fluorescent particles 202; for example, 5-10 times. Since the scattering particles 203 and fluorescent particles 202 are dispersed in the fluorescent layer 20, the scattering particles 203 are more easily dispersed in the gaps between the fluorescent particles 202. That is, the fluorescent particles 202 are surrounded by scattering particles 203 in the fluorescent layer 20, which can effectively reduce the risk of uneven color temperature caused by the direct emission of blue light from the light-emitting surface due to the lack of scattering particles 203 between the fluorescent particles 202; and the relative number of the two is more appropriate, the synergistic effect of scattering particles 203 and fluorescent particles 202 is better, and the color temperature stability and contrast of the light-emitting device 1 are better. Specifically, the number of scattering particles 203 within the aforementioned cross section can be, for example, 5 times, 5.2 times, 5.5 times, 5.8 times, 6 times, 6.2 times, 6.5 times, 6.8 times, 7 times, 7.2 times, 7.5 times, 7.5 times, 8 times, 8.2 times, 8.5 times, 8.8 times, 9 times, 9.2 times, 9.5 times, 9.8 times, 10 times, 15 times, 20 times, 25 times, 30 times, 35 times, 40 times, 45 times, 50 times, 55 times, 60 times, 65 times, 70 times, 75 times, 80 times, 85 times, 90 times, 95 times, 100 times, etc.

[0081] In some embodiments of this application, the number of fluorescent particles 202 in the first direction is ≤D1 / D2. This facilitates the thinning of the fluorescent layer 20 while improving contrast.

[0082] In some embodiments of this application, the dimension H of the fluorescent layer 20 in the first direction and the D50 particle size D2 of the fluorescent particles satisfy: |H-3D2|≤40μm. In some specific embodiments, the thickness of the fluorescent layer 20 is approximately three times the D50 particle size (D2) of the fluorescent particles 202. This facilitates the staggered arrangement of the fluorescent particles 202 in the first direction, which is more conducive to the propagation of light through the matrix 201 between the fluorescent particles 202 and the scattering particles 203, thereby improving contrast and color temperature stability. Specifically, the value of |H-3D2| can be, for example, 0, 1μm, 2μm, 3μm, 5μm, 8μm, 10μm, 12μm, 15μm, 18μm, 20μm, 22μm, 25μm, 28μm, 30μm, 32μm, 35μm, 38μm, 40μm, etc.

[0083] In some embodiments of this application, the fluorescent particles 202 in the fluorescent layer are staggered in the first direction. That is, in the fluorescent layer, in the first direction, the orthographic projections of multiple fluorescent particles 202 on the LED layer 10 do not completely overlap. In other words, there are multiple fluorescent particles 202 in the fluorescent layer 20 whose orthographic projections on the LED layer 10 do not overlap or partially overlap.

[0084] In some embodiments of this application, the LED layer 10 of the light-emitting device 1 includes pixels 101 arranged in an array. The outer circle diameter D1 of the surface of each pixel 101 near the fluorescent layer 20 is 100 μm. The thickness H of the fluorescent layer 20 is 20 μm-50 μm. The D50 particle size (D2) of the fluorescent particles 202 is 5 μm-15 μm. The D50 particle size (D3) of the scattering particles 203 is 100 nm-2 μm.

[0085] In other embodiments of this application, the LED layer 10 of the light-emitting device 1 includes an array of pixels 101, the outer circle diameter D1 of each pixel 101 on the surface near the fluorescent layer 20 is 50 μm, the thickness H of the fluorescent layer 20 is 10 μm-20 μm, the D50 particle size (D2) of the fluorescent particles 202 is 3 μm-10 μm, and the D50 particle size (D3) of the scattering particles 203 is 50 nm-1 μm.

[0086] In some embodiments of this application, the LED layer 10 of the light-emitting device 1 includes an array of pixels 101. The outer circle diameter D1 of the surface of each pixel 101 near the fluorescent layer 20 is 20 μm. The thickness H of the fluorescent layer 20 is 5 μm-15 μm. The D50 particle size (D2) of the fluorescent particles 202 is 1 μm-5 μm. The D50 particle size (D3) of the scattering particles 203 is 20 nm-500 nm.

[0087] For some embodiments of this application, please refer to Figure 3In any cross section along the first direction, the region of any pixel 101 of the fluorescent layer 20 within the orthographic projection range of the fluorescent layer 20 includes multiple first regions 21 perpendicular to the first direction. The orthographic projections of the multiple first regions 21 on the LED layer 10 do not overlap, and each first region 21 includes at least one fluorescent particle 202. Each cross section includes at least four first regions 21. Specifically, each of the aforementioned first regions 21 penetrates the fluorescent layer 20 along the first direction. It should be noted that, in any cross section, the orthographic projection of the first region 21 on the LED layer 10 is a line segment; the orthographic projections of multiple first regions 21 not overlapping on the LED layer 10 means that the orthographic projections of any two first regions 21 on the LED layer 10 do not overlap, but can be connected. "Each first region 21 includes at least one fluorescent particle 202" means that the fluorescent particle 202 must completely fall within the corresponding first region 21 to be considered as a fluorescent particle 202 within that first region 21. In some specific embodiments, for any cross-section of any pixel 101, the number of first regions 21 can be, for example, 4, 5, 6, 7, 8, 9, 10, 12, 15, 18, 20, 22, 25, 28, 30, 32, 35, 38, 40, 42, 45, 48, 50, etc. In this way, while ensuring a high conversion efficiency in converting light of the first wavelength to light of the second wavelength, the number of fluorescent particles 202 perpendicular to the first direction in the fluorescent layer 20 can be reduced, thereby reducing the risk of optical crosstalk between pixels 101.

[0088] Please see Figure 4 In some embodiments of this application, any pixel 101 of the fluorescent layer 20, within the region of the orthographic projection of the fluorescent layer 20, on any cross section along the aforementioned first direction, the cross section is located in any region with a width of 10D3 (width 10 times D3) perpendicular to the first direction (see [link to relevant documentation]). Figure 4 The number of scattering particles 203 in the area marked by the black dashed box in the middle is N, and this cross section is located in any area with a width of 10D3 parallel to the first direction mentioned above (see [link to relevant documentation]). Figure 4 The number of scattering particles 203 in region B (marked by the black dashed box) is M, where M ≥ 2N, and both M and N are positive integers. In this embodiment, only scattering particles 203 that fall completely into regions A and B are counted. It should be noted that... (See also...) Figure 4The aforementioned region A penetrates the fluorescent layer on the corresponding cross-section in the first direction; the aforementioned region B penetrates the fluorescent layer on the corresponding cross-section perpendicular to the first direction. Thus, in the light-emitting device 1 provided in this application embodiment, the lateral propagation of light within the fluorescent layer 20 can be more effectively suppressed, reducing the probability of light emanating from the light-emitting surface corresponding to other pixels 101, thereby improving contrast. Specifically, the value of M can be, for example, 2N, 2.5N, 3N, 3.5N, 4N, 4.5N, 5N, 5.5N, 6N, 6.5N, 7N, 7.5N, 8N, 8.5N, 9N, 9.5N, or 10N. M can be, for example, an integer between 2N and 2.5N, or an integer between 2N and 3N, or an integer between 2.5N and 3N, or a positive integer between 3N and 10N. In some specific embodiments, M ≥ (H / D1)N, where M is a positive integer.

[0089] In some embodiments of this application, fluorescent particles 202 are uniformly dispersed in the fluorescent layer 20; and scattering particles 203 are uniformly dispersed in the fluorescent layer 20 perpendicular to the first direction. Thus, the fluorescent layer 20 has a high uniformity, thereby improving the uniformity of the light emission quality of the light-emitting device 1 and facilitating its application in various scenarios.

[0090] In some embodiments of this application, multiple scattering particles 203 are uniformly distributed in the fluorescent layer 20. This makes the fluorescent layer 20 easier to fabricate, and under the same parameters, the uniformly dispersed scattering particles 203 are more conducive to increasing the probability of light emitted from the pixel 101 colliding with the fluorescent particles 202, thus improving color temperature stability and uniformity, and also enhancing contrast.

[0091] In other embodiments of this application, please refer to Figure 5 Along the direction from LED layer 10 to phosphor layer 20, the number of scattering particles 203 gradually decreases. Thus, along the light emission direction of the light-emitting device 1, the refractive index of phosphor layer 20 exhibits a gradual change, which can improve the light emission efficiency of the wavelength-converted light while ensuring high color temperature uniformity and stability. Specifically, along the direction from LED layer 10 to phosphor layer 20, the concentration of scattering particles 203 can decrease linearly or non-linearly; along this direction, the concentration of scattering particles 203 can decrease gradually or not gradually. In some specific embodiments, along the direction from LED layer 10 to phosphor layer 20, the concentration of scattering particles 203 gradually decreases; in the stacking direction perpendicular to LED layer 10 and phosphor layer 20, the scattering particles 203 are uniformly dispersed in phosphor layer 20.

[0092] In the embodiments of this application, Figures 1 to 5All of these are exemplary drawing methods. The thickness and shape of the LED layer 10 and the fluorescent layer 20, the cross-sectional shape of the pixel 101, and the shape and size of the surface of the pixel 101 near the fluorescent layer 20 in each figure do not constitute a limitation on this application. The relative position, size, and shape of the fluorescent particles 202 and the scattering particles 203 in each figure also do not constitute a limitation on this application.

[0093] In some embodiments of this application, the absorption rate of the scattering particles 203 for both the first wavelength and the second wavelength of light in the fluorescent layer 20 is ≤3%. In some specific embodiments, the absorption rate of the scattering particles 203 for light with wavelengths of 430nm-480nm and 480nm-750nm is ≤3%. This reduces the loss of the first wavelength light emitted from the pixel 101 and the second wavelength light obtained after conversion by the fluorescent particles 202, thereby improving the light extraction efficiency. Specifically, the absorption rate of the scattering particles 203 for the semiconductor emission wavelength and fluorescence wavelength can be, for example, 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 2.8%, or 3%.

[0094] In some embodiments of this application, the refractive index of the scattering particles 203 in the visible light band is greater than that of the matrix 201 in the visible light band. Controlling the refractive index of the scattering particles 203 to be greater than that of the matrix 201 can improve the optical scattering effect at their interface, and the greater the difference in refractive index, the better the optical scattering at the interface. In some specific embodiments, the refractive index of the scattering particles 203 in the visible light band is 1.5-2.5, and the refractive index of the matrix 201 in the visible light band is 1.5-1.7.

[0095] In some embodiments of this application, the refractive index of the fluorescent particles 202 in the visible light band is greater than that of the matrix 201 in the visible light band. In some specific embodiments, the refractive index of the fluorescent particles 202 in the visible light band is approximately 1.8, for example, 1.75-1.85. Similarly, controlling the refractive indices of the fluorescent particles 202 and the matrix 201 to satisfy the above relationship is beneficial to the scattering of light at the interface between the fluorescent particles 202 and the matrix 201, and the greater the difference in their refractive indices, the more beneficial it is to the scattering of light at their interface.

[0096] In some specific embodiments, in the fluorescent layer 20, the refractive index of the scattering particles 203 in the visible light band is greater than that of the matrix 201 in the visible light band, and the refractive index of the fluorescent particles 202 is greater than that of the matrix 201.

[0097] In some embodiments of this application, the material of the scattering particles 203 includes, but is not limited to, one or more of zirconium oxide, titanium oxide, aluminum oxide, and silicon dioxide. Specifically, for example, a single scattering particle 203 may include one or more of the above-mentioned materials, or the scattering particles 203 in the fluorescent layer 20 may include one or more of zirconium oxide particles, titanium oxide particles, aluminum oxide particles, and silicon dioxide particles.

[0098] In some embodiments of this application, the matrix 201 is made of resin. Specifically, the matrix 201 is made of, but is not limited to, silicone resin.

[0099] In some embodiments of this application, the fluorescent particle 202 is made of one or more of cerium-doped yttrium aluminum garnet (Ce:YAG) and quantum dots.

[0100] For some embodiments of this application, please refer to Figure 6 The light-emitting device 1 further includes a substrate 30, and an LED layer 10 and a phosphor layer 20 are sequentially disposed on the surface of the substrate 30 along a first direction. In this embodiment, the substrate 30 may be a flexible substrate or a non-flexible substrate; it may be a transparent substrate or a non-transparent substrate. Figure 6 This is an example drawing method. Figure 6 The thickness and other parameters of the substrate 30 do not constitute a limitation on this application.

[0101] In some embodiments of this application, the fabrication of the light-emitting device 1 includes:

[0102] S1. The aforementioned fluorescent layer 20 is formed on one side surface of the LED layer 10. The process for forming the fluorescent layer 20 includes, but is not limited to, spraying.

[0103] In some embodiments, the matrix 201, fluorescent particles 202 and scattering particles 203 can be mixed first to obtain a first mixture, and then the first mixture can be sprayed onto the surface of the LED layer 10, and then the fluorescent layer 20 can be formed by curing and other processes to obtain the light-emitting device 1.

[0104] In other embodiments, the mixed matrix 201 and fluorescent particles 202 are mixed to obtain a second mixture, and the mixed matrix 201 and scattering particles 203 are mixed to obtain a third mixture. The second mixture is ejected from a first nozzle, and the third mixture is ejected from a second nozzle. After curing and other processes, a fluorescent layer 20 is formed to obtain a light-emitting device 1.

[0105] In some other embodiments, the first nozzle may spray the second mixture, and the second nozzle may spray the scattering particles 203.

[0106] It is understood that the fluorescent layer 20 can be formed by multiple layering and spraying, for example, five times. In some specific embodiments, the concentration of scattering particles 203 along the light emission direction of the light-emitting device 1 can be gradually varied by adjusting the amount of scattering particles 203 used in each spraying.

[0107] This application also provides a lighting fixture, including the light-emitting device 1 provided in this application embodiment. In some embodiments of this application, the above-mentioned lighting fixture includes, but is not limited to, vehicle lights, such as pixelated vehicle lights. Due to the inclusion of the light-emitting device 1 provided in this application embodiment, the lighting fixture can have both high contrast and high color temperature stability and color temperature uniformity, meeting the needs of daily driving and night driving.

[0108] This application also provides a vehicle, including the lighting fixture provided in this application embodiment, or including the light-emitting device 1 provided in this application embodiment. In some embodiments, the vehicle includes the pixelated vehicle lights provided in this application embodiment. Due to the use of the pixelated vehicle lights provided in this application embodiment, the vehicle has stronger market competitiveness. In some embodiments of this application, the above-mentioned vehicle includes, but is not limited to, new energy vehicles, fuel vehicles, and rail trains.

[0109] The light-emitting device 1 of this application embodiment can also be applied to other display technologies, such as displays for consumer electronics, automotive displays, medical displays, displays for augmented reality (AR) devices, displays for virtual reality (VR) devices, displays for smart home systems, transparent displays, and displays for professional markets.

[0110] In some embodiments of this application, the LED layer 10 of the light-emitting device 1 is a Micro-LED layer, which can provide high resolution and high contrast display effects, as well as vivid colors, and has low power consumption and long service life.

[0111] In some embodiments of this application, when the light-emitting device 1 is applied to consumer electronics products, it can be used to provide ultra-large screen displays and small screen displays for smartwatches. When the light-emitting device 1 is applied to automotive displays, it can enhance the visual experience of dashboards and central control screens. When the light-emitting device 1 is used in medical displays, it is particularly suitable for fields such as telemedicine, preoperative assessment, intraoperative navigation, and medical explanation. The light-emitting device 1 can be combined with a flexible substrate (i.e., the substrate is a flexible substrate) to achieve flexible displays, which are particularly suitable for AR and VR devices. When the light-emitting device 1 is used in smart home systems, it can be applied to devices such as home appliance displays and smart mirrors. The light-emitting device 1 can also be applied to transparent displays, such as electronic signage, commercial displays, and business conference rooms. When the light-emitting device 1 is applied to the professional display market, it is particularly suitable for the high-end television and professional display markets.

[0112] This application also provides a terminal device, including a display module. The display module includes a display panel and a light-emitting device 1 provided in this application embodiment, wherein the light-emitting device 1 and the display panel are stacked together. Due to the use of the light-emitting device 1 provided in this application embodiment, this terminal device has strong market competitiveness and a promising market prospect.

[0113] It should be understood that the use of the terms "first," "second," and various numerical designations in this document is merely for descriptive convenience and is not intended to limit the scope of this application.

[0114] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after it are in an "or" relationship.

[0115] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0116] In this application, "-" indicates a range value, including the endpoint values ​​at both ends. For example, the value of a can be 0.5-15, meaning that the value of a can be between 0.5 and 15, and includes the endpoint values ​​of 0.5 and 15.

Claims

1. A light-emitting device, characterized in that, include: An LED layer and a phosphor layer are stacked along a first direction; The LED layer includes multiple pixels arranged in an array, and the circumcircle diameter of the surface of each pixel near the fluorescent layer is D1; The fluorescent layer includes a matrix and a plurality of fluorescent particles and a plurality of scattering particles dispersed in the matrix. The fluorescent particles are used to convert light of a first wavelength into light of a second wavelength. The D50 particle size of the fluorescent particles is D2, and the D50 particle size of the scattering particles is D3, where D2>D3. In any cross section along the first direction, the total cross-sectional area of ​​the plurality of fluorescent particles in the region within the orthogonal projection range of any pixel of the fluorescent layer is ≥50%, and the total cross-sectional area of ​​the plurality of scattering particles is ≤5%. The size of the fluorescent layer in the first direction is H; wherein, H≤D1 or H≤60μm.

2. The light-emitting device according to claim 1, characterized in that, In any cross section along the first direction, within the orthogonal projection range of any pixel of the fluorescent layer, the total cross-sectional area of ​​the plurality of fluorescent particles accounts for 50%-90%, and the total cross-sectional area of ​​the plurality of scattering particles accounts for 0.01%-5%.

3. The light-emitting device according to claim 1 or 2, characterized in that, The conditions D1 and D2 satisfy: D2≤1 / 4D1.

4. The light-emitting device according to any one of claims 1-3, characterized in that, The D2 satisfies: D2≤15μm.

5. The light-emitting device according to any one of claims 1-4, characterized in that, The D3 satisfies: 10nm≤D3≤10μm.

6. The light-emitting device according to any one of claims 1-5, characterized in that, In any cross section along the first direction, the number of scattering particles in the region within the orthogonal projection range of any pixel of the fluorescent layer is ≥ 5 times the number of fluorescent particles.

7. The light-emitting device according to any one of claims 1-6, characterized in that, In the fluorescent layer, the number of fluorescent particles in the first direction is ≤D1 / D2.

8. The light-emitting device according to any one of claims 1-7, characterized in that, The H and D2 satisfy: |H-3D2|≤40μm.

9. The light-emitting device according to any one of claims 1-8, characterized in that, In any cross section along the first direction, the region within the orthographic projection range of any pixel of the fluorescent layer on the fluorescent layer includes at least four first regions perpendicular to the first direction, and the orthographic projections of the first regions on the LED layer do not overlap; wherein each first region includes at least one fluorescent particle.

10. The light-emitting device according to any one of claims 1-9, characterized in that, In any region of the orthogonal projection of any pixel of the fluorescent layer onto the fluorescent layer, along any cross section of the first direction, the number of scattering particles in any region of the cross section with a width of 10D3 perpendicular to the first direction is N; the number of scattering particles in any region of the cross section with a width of 10D3 parallel to the first direction is M, where M≥2N, and both M and N are positive integers.

11. The light-emitting device according to any one of claims 1-10, characterized in that, The D1 satisfies: D1≤300μm.

12. The light-emitting device according to any one of claims 1-11, characterized in that, The multiple scattering particles are uniformly distributed in the fluorescent layer.

13. The light-emitting device according to any one of claims 1-12, characterized in that, The number of scattering particles gradually decreases along the direction from the LED layer to the fluorescent layer.

14. The light-emitting device according to any one of claims 1-13, characterized in that, The scattering particles have an absorption rate of ≤3% for light of the first wavelength and light of the second wavelength.

15. The light-emitting device according to any one of claims 1-14, characterized in that, The first wavelength is 430nm-480nm, and the second wavelength is 480nm-750nm.

16. The light-emitting device according to any one of claims 1-15, characterized in that, In the fluorescent layer, the refractive index of the scattering particles in the visible light band is greater than the refractive index of the matrix in the visible light band; and / or, The refractive index of the fluorescent particles in the visible light band is greater than that of the matrix in the visible light band.

17. The light-emitting device according to any one of claims 1-16, characterized in that, The scattering particles are made of one or more of zirconium oxide, titanium oxide, aluminum oxide, and silicon dioxide. And / or, the fluorescent particles are made of one or more of cerium-doped yttrium aluminum garnet and quantum dots; And / or, the matrix material includes resin.

18. A lamp, characterized in that, Includes the light-emitting device as described in any one of claims 1-17.

19. A vehicle, characterized in that, Includes the luminaire as described in claim 18, or includes the light-emitting device as described in any one of claims 1-17.

20. A terminal device, characterized in that, The device includes a display module, which comprises a display panel and a light-emitting device as described in any one of claims 1-17, wherein the light-emitting device is stacked on top of the display panel.

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