Light-emitting substrate and display device

Abstract

The application provides a light-emitting substrate and a display device. The light-emitting substrate comprises a light-transmitting substrate, a first reflecting layer, a light-emitting unit and a condenser lens. The light-transmitting substrate comprises a first surface and a second surface; the first reflecting layer is provided with at least one through hole; the light-emitting unit comprises at least one light-emitting element; the condenser lens is located between the light-transmitting substrate and the light-emitting unit, and the condenser lens converges light emitted by the light-emitting unit; the main optical axis of each condenser lens is projected onto the second surface and located in the projection of the through hole on the second surface; one light-emitting unit is opposite to one condenser lens, and the light-emitting area of each light-emitting element of the light-emitting unit is projected onto the second surface and overlaps with the projection of the corresponding condenser lens on the second surface; the light-emitting area of each light-emitting element of one light-emitting unit is projected onto the second surface and does not overlap with the main optical axis of the corresponding condenser lens on the second surface. The thickness of the light-emitting substrate as a whole can be reduced.

Description

Technical Field

[0001] This application relates to the field of display technology, specifically to a light-emitting substrate and a display device. Background Technology

[0002] The liquid crystal display device includes a liquid crystal display panel and a backlight module, and the backlight module includes an edge-lit backlight module and a direct-lit backlight module.

[0003] Direct-lit backlight modules are located on the side of the display panel furthest from the light-emitting surface. Direct-lit backlight modules typically require multiple layers of prism films and diffuser films to improve light uniformity, resulting in a larger thickness for direct-lit backlight modules. Summary of the Invention

[0004] This application provides a light-emitting substrate, including:

[0005] A light-transmitting substrate, comprising a first surface and a second surface opposite to each other;

[0006] A first reflective layer is located on the side of the light-transmitting substrate away from the second surface, and the first reflective layer has at least one through hole;

[0007] The light-emitting unit is located on the same side of the light-transmitting substrate as the first reflective layer, and the light-emitting unit includes at least one light-emitting element;

[0008] A condensing lens is located between the light-transmitting substrate and the light-emitting unit, and the condensing lens converges the light emitted by the light-emitting unit; the orthographic projection of the principal optical axis of each condensing lens on the second surface lies within the orthographic projection of a through hole on the second surface; one light-emitting unit is opposite to one condensing lens, and the orthographic projection of the light-emitting area of ​​each light-emitting element of the light-emitting unit on the second surface overlaps with the orthographic projection of the corresponding condensing lens on the second surface; the orthographic projection of the light-emitting area of ​​each light-emitting element of the light-emitting unit on the second surface does not overlap with the orthographic projection of the principal optical axis of the corresponding condensing lens on the second surface.

[0009] In some embodiments, in a direction perpendicular to the second surface, the distance between the surface of the light-emitting element facing the condenser lens and the optical center O of the condenser lens is h, where 10 μm ≤ h ≤ 30 μm.

[0010] In some embodiments, the light-emitting unit includes a plurality of light-emitting elements, and the orthographic projections of the plurality of light-emitting elements of the same light-emitting unit on the second surface surround the orthographic projections of the principal optical axis of the corresponding condenser lens on the second surface.

[0011] In some embodiments, the distance between the geometric center of the orthographic projection of each light-emitting element on the second surface and the orthographic projection of the principal optical axis of the condenser lens on the second surface is the same.

[0012] In some embodiments, the number of light-emitting elements in the light-emitting unit is four.

[0013] In some embodiments, a plurality of light-emitting elements of the light-emitting unit are connected in series.

[0014] In some embodiments,

[0015] Wherein, D is the maximum width of the light-emitting area of ​​the light-emitting element in the direction parallel to the second surface, L is the aperture of the condensing lens, h is the distance between the surface of the light-emitting element facing the condensing lens and the optical center O of the condensing lens in the direction perpendicular to the second surface, b is the thickness of the light-transmitting substrate in the direction perpendicular to the second surface, and X is the distance between the geometric center of the orthographic projection of the light-emitting element on the second surface and the orthographic projection of the principal optical axis of the condensing lens on the second surface in the direction parallel to the second surface.

[0016] In some embodiments, the light-emitting substrate further includes a filler layer located between the condensing lens and the light-emitting element, wherein the filler layer is made of any one of epoxy resin, silicone, or polymethyl methacrylate.

[0017] In some embodiments, the surface of the first reflective layer facing the light-transmitting substrate has a plurality of spaced light-collecting structures.

[0018] In some embodiments, the light-emitting substrate further includes a plurality of microstructures located on the side of the light-transmitting substrate facing the first reflective layer, wherein,

[0019] The light-collecting structure is a first protrusion, and the microstructure is a recessed structure, with each first protrusion located within a corresponding recessed structure; or...

[0020] The light-collecting structure is a recessed portion, and the microstructure is a second protrusion, with each recessed portion covering the corresponding second protrusion.

[0021] In some embodiments, the focusing lens is a convex lens, a Fresnel lens, or a metasurface lens.

[0022] In some embodiments, when the condensing lens is a convex lens, the condensing lens includes a third surface facing the light-emitting element and a fourth surface facing the light-transmitting substrate, and at least one of the third surface and the fourth surface is a curved surface.

[0023] In some embodiments, the light-emitting substrate further includes a second reflective layer disposed on the side of the light-emitting unit away from the condenser lens, wherein the orthographic projection of each light-emitting element of the light-emitting unit on the second surface falls within the orthographic projection of the second reflective layer on the second surface.

[0024] In some embodiments, the material of the second reflective layer includes at least one of white ink and silicone-based white glue.

[0025] This application also provides a display device, including the light-emitting substrate as described above.

[0026] The beneficial effects of this application include:

[0027] In this embodiment, because the light-emitting elements in the light-emitting unit are misaligned with the principal optical axis of the corresponding condensing lens, the angle of the incident light rays is deflected after being converged by the condensing lens. When the deflected light rays are incident on the second surface of the light-transmitting substrate, the incident area is located on the side where the orthographic projection of the corresponding light-emitting element on the second surface of the light-transmitting substrate is far from the principal optical axis of the condensing lens. This allows most of the light rays that undergo total internal reflection on the second surface to be incident on the first reflective layer, and then reflect multiple times between the second surface and the first reflective layer before finally exiting through the second surface. This reduces the probability of light rays emitted from the light-emitting area of ​​the light-emitting element directly exiting through the light-transmitting substrate, improving the uniformity of the emitted light. Thus, the light-emitting substrate does not need to have multilayer prism films and diffusion films or has fewer light-uniforming structures, which helps to reduce the overall thickness of the light-emitting substrate.

[0028] Additional aspects and advantages of this application will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of this application. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0030] Figure 1 The image shown is a top view of a portion of the structure of a light-emitting substrate provided in an exemplary embodiment of this application;

[0031] Figure 2 As shown Figure 1 A sectional view taken along section line AA.

[0032] Figure 3 The image shown is an exemplary embodiment of the light-emitting substrate provided in this application. Figure 1 A sectional view taken along section line AA.

[0033] Figure 4As shown Figure 3 A top view of a portion of the structure in the light-emitting substrate shown;

[0034] Figure 5 The image shown is a top view of a portion of the structure of a light-emitting substrate provided in an exemplary embodiment of this application;

[0035] Figure 6 The image shown is an exemplary embodiment of the light-emitting substrate provided in this application. Figure 1 A sectional view taken along section line AA.

[0036] Figure 7 The image shown is an exemplary embodiment of the light-emitting substrate provided in this application. Figure 1 A sectional view taken along section line AA.

[0037] In the figure: 1-Transparent substrate; 101-First surface; 102-Second surface; 11-Microstructure; 111-Recessed structure; 112-Second protrusion; 2-First reflective layer; 201-Through hole; 3-Light-emitting unit; 3a-Light-emitting area; 31-Light-emitting element; 31a-First light-emitting element; 31b-Second light-emitting element; 31c-Third light-emitting element; 31d-Fourth light-emitting element; 32-Fixing plate; 33-Pin; 4-Condensing lens; 5-Filling layer; 6-Conductive pad; 7-Light-collecting structure; 71-First protrusion; 72-Recessed portion; 7a-First light-collecting area; 7b-Second light-collecting area; 8-Second reflective layer; 9-Insulating layer; CC-Main optical axis. Detailed Implementation

[0038] The present application will be described more fully below with reference to the accompanying drawings in which embodiments are illustrated.

[0039] It should be noted that when element A, such as a layer, film, or region, is referred to as "on the side of element B away from element C," it means that element A can be directly on the surface of element B on the side away from element C, or that an intermediate layer, intermediate region, or intermediate element may exist between element B and element A. When element A, such as a layer, film, or region, is referred to as "between element B and element C," it means that only element A exists between element B and element C, or that an intermediate layer, intermediate region, or intermediate element may exist between element A and element B, or between element A and element C.

[0040] While terms such as "first," "second," etc., can be used to describe various components, such components are not limited by these terms. These terms are only used to distinguish one component from another and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more. Where there is no conflict, the features in the embodiments described below in this application may complement or combine with each other.

[0041] In the accompanying drawings, the symbols "x", "y", and "z" are used to indicate directions. The x, y, and z directions are not limited to three mutually perpendicular directions in a Cartesian coordinate system and can be interpreted in a broader sense. For example, the x, y, and z directions can be perpendicular to each other, or they can represent different directions that are not perpendicular to each other. Exemplarily, x indicates a first direction, y indicates a second direction perpendicular to the first direction, and z indicates a third direction perpendicular to both the first and second directions. The first direction x, the second direction y, and the third direction z can correspond to the horizontal direction, vertical direction, and thickness direction of the light-emitting substrate, respectively.

[0042] In the accompanying drawings, the dimensions and thicknesses of the elements may be enlarged for better understanding, clarity, and ease of description. However, this application is not limited to the dimensions and thicknesses shown in the drawings. The thicknesses of layers, films, panels, areas, and other elements may be exaggerated in the drawings for clarity. Example embodiments are shown in the drawings, wherein the same reference numerals denote the same elements.

[0043] like Figure 1 and Figure 2As shown, the light-emitting substrate includes a light-transmitting substrate 1, a first reflective layer 2, a light-emitting unit 3, and a focusing lens 4. The light-transmitting substrate 1 includes a first surface 101 and a second surface 102 facing each other; a first reflective layer 2 is located on the side of the light-transmitting substrate 1 away from the second surface 102, and the first reflective layer 2 is provided with at least one through hole 201; a light-emitting unit 3 is located on the same side of the light-transmitting substrate 1 as the first reflective layer 2, and the light-emitting unit 3 includes at least one light-emitting element 31; a condensing lens 4 is located between the light-transmitting substrate 1 and the light-emitting unit 3, and the condensing lens 4 converges the light emitted by the light-emitting unit 3; the geometric center of the orthographic projection of the principal optical axis CC of each condensing lens 4 on the second surface 102 is located within the orthographic projection of a through hole 201 on the second surface 102; a light-emitting unit 3 is opposite to a condensing lens 4, and the orthographic projection of the light-emitting area 3a of each light-emitting element 31 of the light-emitting unit 3 on the second surface 102 overlaps with the orthographic projection of the corresponding condensing lens 4 on the second surface 102; the orthographic projection of the light-emitting area 3a of each light-emitting element 31 of the light-emitting unit 3 on the second surface 102 does not overlap with the orthographic projection of the principal optical axis CC of the corresponding condensing lens 4 on the second surface 102.

[0044] In this embodiment, since the light-emitting elements 31 in the light-emitting unit 3 are misaligned with the principal optical axis CC of the corresponding condensing lens 4, the angle of the incident light rays is deflected after the light emitted by the light-emitting elements 31 is converged by the condensing lens 4. When the deflected light rays are incident on the second surface 102 of the light-transmitting substrate 1, the incident area is located on the side where the orthographic projection of the corresponding light-emitting element 31 on the second surface 102 of the light-transmitting substrate 1 is far from the principal optical axis CC of the condensing lens 4. As a result, most of the light rays that undergo total internal reflection on the second surface 102 can be incident on the first reflective layer 2 and reflected multiple times between the second surface 102 and the first reflective layer 2 before finally exiting through the second surface 102. This reduces the probability that the light emitted from the light-emitting area of ​​the light-emitting element 31 will directly exit through the light-transmitting substrate 1, improving the uniformity of the emitted light. Thus, the light-emitting substrate does not need to have multilayer prism films and diffusion films or the number of light-uniforming structures can be reduced, which is beneficial to reducing the overall thickness of the light-emitting substrate.

[0045] In some embodiments, such as Figure 1 and Figure 2 As shown, the orthographic projection of the condenser lens 4 on the second surface 102 and the orthographic projection of the through hole 201 on the second surface 102 are almost completely coincident. This avoids the gap between the inner edge of the through hole 201 and the outer edge of the condenser lens 4, allowing the light emitted by the light-emitting element 31 to pass through the condenser lens 4 and enter the light-transmitting substrate 1, thus preventing the light from passing through the gap between the condenser lens 4 and the first reflective layer 2 and directly entering the light-transmitting substrate 1, which would prevent the incident light from undergoing total internal reflection.

[0046] In other embodiments, the projected area of ​​the orthogonal projection of the through hole 201 on the second surface 102 is larger than the projected area of ​​the orthogonal projection of the condenser lens 4 on the second surface 102 (not shown in the figure).

[0047] In other embodiments, the orthographic projection of the condenser lens 4 on the second surface 102 and the orthographic projection of the first reflective layer 2 on the second surface 102 do not overlap.

[0048] In some embodiments, such as Figure 2 As shown, the orthographic projection of the light-emitting area 3a of each light-emitting element 31 of the light-emitting unit 3 onto the second surface 102 is located within the orthographic projection of the condenser lens 4 onto the second surface 102. This allows more light emitted from the light-emitting area 3a of the light-emitting element 31 to enter the condenser lens 4, preventing some light emitted from the light-emitting area 3a of the light-emitting element 31 from being unable to be focused by the condenser lens 4.

[0049] In other embodiments, a portion of the light-emitting area 3a of each light-emitting element 31 of the light-emitting unit 3 is projected onto the second surface 102 within the orthogonal projection of the condenser lens 4 onto the second surface 102, while another portion is projected onto the outside of the orthogonal projection of the condenser lens 4 onto the second surface 102.

[0050] In some embodiments, such as Figure 2 As shown, the first reflective layer 2 is located on the side of the light-emitting unit 3 closest to the light-transmitting substrate 1. In other embodiments, the first reflective layer 2 is disposed on the side of the light-emitting unit 3 furthest from the light-transmitting substrate 1 (not shown in the figure).

[0051] In some embodiments, when the first reflective layer 2 is located on the side of the light-emitting unit 3 near the light-transmitting substrate 1, the condensing lens 4 can be located within the through-hole 201 of the first reflective layer 2. This can reduce the overall thickness of the light-emitting substrate.

[0052] In some embodiments, the light-emitting substrate further includes a plurality of conductive pads 6 disposed on the side of the first reflective layer 2 away from the light-transmitting substrate 1, and each light-emitting unit 3 includes at least two pins 33, each pin 33 being connected to a conductive pad 6. The light-emitting substrate may also include signal lines disposed on the same layer as the conductive pads 6.

[0053] In some embodiments, the first reflective layer 2 is made of a metallic material. Preferably, the first reflective layer 2 comprises at least one of aluminum, silver, copper, and platinum. When the first reflective layer 2 is made of a metallic material, the light-emitting substrate further comprises an insulating layer 9, which is located between the first reflective layer 2 and the conductive pad 6, to prevent short circuits between different conductive pads 6 caused by the formation of an electrical connection between the conductive pad 6 and the first reflective layer 2.

[0054] In some embodiments, the light-emitting unit 3 further includes a fixing plate 32, which is used to fix the light-emitting elements 31 and covers the sides of each light-emitting element 31; the material of the fixing plate 32 may be a reflective material. Figure 2 As shown, the light-emitting substrate also includes a second reflective layer 8, which covers the surface of the light-emitting unit 3 away from the condenser lens 4. Thus, the arrangement of the second reflective layer 8 and the fixing plate 32 allows the light emitted by each light-emitting element 31 to exit from the light-emitting element 31 toward the surface of the light-transmitting substrate 1, and the surface of the light-emitting element 31 toward the light-transmitting substrate 1 is the light-emitting area 3a of the light-emitting element 31. The shape of the fixing plate 32 and the surface of the second reflective layer 8 allows the light emitted by the light-emitting element 31 at large angles to be reflected multiple times between the first reflective layer 2 and the second reflective layer 8 to form a waveguide before being reflected onto the fixing plate 32, and then onto the condenser lens for utilization, thereby improving the light utilization rate.

[0055] In some embodiments, the material of the second reflective layer 8 includes at least one of white ink and silicone-based white glue.

[0056] In some embodiments, the light-emitting element 31 may include a Micro LED and / or a Mini LED. The size (e.g., length) of the Micro LED is less than 50 μm, for example, 10 μm to 50 μm. The size (e.g., length) of the Mini LED is 50 μm to 150 μm, for example, 80 μm to 120 μm.

[0057] In some embodiments, the refractive index of the light-transmitting substrate 1 is greater than that of air. In some embodiments, the material of the light-transmitting substrate 1 may be any one of glass, quartz, polymethyl methacrylate (PMMA), etc.

[0058] In some embodiments, such as Figure 2As shown, in a direction perpendicular to the second surface 102, the distance between the surface of the light-emitting element 31 facing the condenser lens 4 and the optical center O of the condenser lens 4 is h, and the focal length of the condenser lens is f, where f < h ≤ 2f. This allows the light rays passing through the condenser lens 4 to form an inverted, magnified, or inverted, same-size real image on the second surface 102. Specifically, when f < h < 2f, the light rays passing through the condenser lens 4 form an inverted, magnified real image on the second surface 102. When h = 2f, the light rays passing through the condenser lens 4 form an inverted, same-size real image on the second surface 102. Therefore, since the light rays incident on the second surface 102 form a magnified or same-size real image in the side region relative to the orthographic projection of the condenser lens 4 onto the second surface 102, the proportion of light rays with an incident angle greater than the critical angle of total internal reflection of the second surface 102 can be increased. Preferably, the focal length of the condenser lens 4 can be adjusted so that when light rays pass through the condenser lens 4 and are incident on the second surface 102, an inverted and magnified real image is formed. This ensures that the angle between all light rays incident on the second surface 102 and the normal to the second surface 102 is greater than the critical angle for total internal reflection of the second surface 102, thus enabling all light rays incident on the second surface 102 to achieve total internal reflection.

[0059] It should be noted that the critical angle for total internal reflection refers to the minimum angle of incidence at which total internal reflection occurs when light travels from a high-refractive-index medium to a low-refractive-index medium. It can be calculated using Snell's Law, specifically: θ = arcsin(n2 / n1). Here, θ is the critical angle for total internal reflection on the second surface 102, n1 is the refractive index of the medium the light passes through before reaching the second surface 102, and n2 is the refractive index of the medium the light enters after passing through the second surface 102. In this embodiment, the medium the light passes through before reaching the second surface 102 is the transparent substrate 1, and the medium the light enters after passing through the second surface 102 is air. In one embodiment, when the transparent substrate 1 is glass (refractive index 1.5), θ = arcsin(n2 / n1) = arcsin(1 / 1.5) ≈ 42°. That is, total internal reflection occurs when at least a portion of the incident light on the second surface 102 forms an angle α with the normal to the second surface 102 greater than 42°.

[0060] In some embodiments, the value of h can be in the range of 10μm ≤ h ≤ 30μm. The focal length of the condenser lens 4 can be designed by the value of h, and the Gaussian imaging formula is: Where f is the focal length of the condenser lens 4; h is the distance between the surface of the light-emitting element 31 facing the condenser lens 4 and the optical center O of the condenser lens 4 in the direction perpendicular to the second surface 102; and b is the thickness of the light-transmitting substrate 1 in the direction perpendicular to the second surface 102. It can be seen that by adjusting the values ​​of h and b, the corresponding f can be obtained so that h satisfies f < h ≤ 2f. In one example, when h is 30 μm and b is 500 μm, the focal length f is 28.3 μm, and at this time h = 30 μm satisfies the condition f < h ≤ 2f.

[0061] In some embodiments, such as Figure 1 As shown, the light-emitting unit 3 includes multiple light-emitting elements 31. The orthographic projections of the multiple light-emitting elements 31 of the same light-emitting unit 3 on the second surface 102 surround the orthographic projections of the principal optical axis CC of the corresponding condenser lens 4 on the second surface 102.

[0062] In this embodiment, when multiple light-emitting elements 31 of the same light-emitting unit 3 are arranged around the condensing lens 4, the light emitted from the light-emitting area 3a of each light-emitting element 31 of the light-emitting unit 3 is more evenly distributed on the second surface after passing through the condensing lens 4, which can further improve the effect of uniform light.

[0063] In some embodiments, in the same light-emitting unit 3, the distances d1, d2, d3, and d4 between the geometric centers of the orthographic projections of any two adjacent light-emitting elements 31 on the second surface 102 are all the same. This arrangement can further improve the uniformity of light emission from the light-emitting substrate.

[0064] In some embodiments, the distance between the geometric center of the orthographic projection of each light-emitting element 31 on the second surface 102 and the distance between the orthographic projection of the principal optical axis CC of the condenser lens 4 on the second surface 102 are the same. Specifically, as Figure 1As shown, the light-emitting unit 3 includes a first light-emitting element 31a, a second light-emitting element 31b, a third light-emitting element 31c, and a fourth light-emitting element 31d; the distances d5, d6, d7, d8, between the geometric center of the orthographic projection of the first light-emitting element 31a on the second surface 102 and the orthographic projection of the principal optical axis CC of the condenser lens 4 on the second surface 102 are all the same. Thus, the geometric center of the area enclosed by the light-emitting elements 31 of the same light-emitting unit 3 overlaps with the orthographic projection of the principal optical axis CC of the condenser lens 4 onto the second surface 102, which makes the light emitted by each light-emitting element 31 in the same light-emitting unit more evenly distributed when incident on the second surface 102, further improving the light emission uniformity of the light-emitting substrate.

[0065] In some embodiments, such as Figure 1 As shown, the number of light-emitting elements 31 in the light-emitting unit 3 is four. Specifically, the light-emitting unit 3 includes a first light-emitting element 31a, a second light-emitting element 31b, a third light-emitting element 31c, and a fourth light-emitting element 31d arranged sequentially around the main optical axis CC. The line connecting the geometric center of the orthographic projection of the first light-emitting element 31a on the second surface 102 and the geometric center of the orthographic projection of the third light-emitting element 31c on the second surface 102 is parallel to the first direction x, and the geometric center of the orthographic projection of the second light-emitting element 31b on the second surface 102 and the geometric center of the orthographic projection of the fourth light-emitting element 31d on the second surface 102 is parallel to the second direction y. The first direction x and the second direction y intersect. Preferably, the first direction x and the second direction y are perpendicular, and the geometric centers of the orthographic projections of the first light-emitting element 31a, the second light-emitting element 31b, the third light-emitting element 31c, and the fourth light-emitting element 31d on the second surface 102, when connected sequentially, form a rhombus or a square. Preferably, the geometric center of the orthographic projection of the second light-emitting element 31b on the second surface 102, the geometric center of the orthographic projection of the third light-emitting element 31c on the second surface 102, and the geometric center of the orthographic projection of the fourth light-emitting element 31d on the second surface 102 are connected in sequence to form a square.

[0066] In some embodiments, the light-emitting substrate includes a plurality of light-emitting units 3 arranged in multiple rows and columns. The light-emitting units 3 are arranged at intervals in mutually perpendicular row and column directions, respectively. The row direction is the same as the first direction x, and the column direction is the same as the second direction y. Since the line connecting the geometric center of the orthographic projection of the first light-emitting element 31a on the second surface 102 and the geometric center of the orthographic projection of the third light-emitting element 31c on the second surface 102 is parallel to the first direction x, the line connecting the geometric centers of the orthographic projections of the first light-emitting element 31a and the third light-emitting element 31c on the second surface 102 is parallel to the row direction. Since the line connecting the geometric centers of the orthographic projections of the second light-emitting element 31b and the fourth light-emitting element 31d on the second surface 102 is parallel to the second direction y, the line connecting the geometric centers of the orthographic projections of the second light-emitting element 31b and the fourth light-emitting element 31d on the second surface 102 is parallel to the column direction.

[0067] In one example, such as Figure 2 As shown, the distance between the geometric center of the orthographic projection of each light-emitting element 31 on the second surface 102 and the orthographic projection of the corresponding principal optical axis CC of the condenser lens 4 on the second surface 102 is X. The aperture of the condenser lens 4 is L, and X is one-quarter of L. Therefore, the orthographic projections of each light-emitting element 31 on the second surface 102 can be evenly distributed within the orthographic projection of the condenser lens 4 on the second surface 102, making the light output more uniform.

[0068] In other embodiments, the number of light-emitting elements in the light-emitting unit 3 is greater than or equal to 3 and not equal to 4, and the geometric centers of the orthographic projections of all light-emitting elements in the same light-emitting unit 3 on the second surface 102 are connected sequentially to form a regular polygon.

[0069] In some embodiments, multiple light-emitting elements 31 of the light-emitting unit 3 are connected in series. Thus, the same light-emitting unit 3 includes a cathode pin and an anode pin, that is, a light-emitting unit 3 only needs to be provided with two pins 33 for connecting to the conductive pad 6 respectively. Compared with providing a separate pin for each light-emitting element 31, the number of pins 33 in the light-emitting unit 3 can be reduced, and the conductive pad 6 connected to the pin 33 is avoided from occupying the space of the light-emitting substrate. As a result, more space on the light-emitting substrate can be used to place the light-emitting elements and the condenser lens 4, thereby improving the integration of the light-emitting substrate.

[0070] In some embodiments, such as Figure 2As shown, based on the light path of the light emitted from each light-emitting element 31 of the light-emitting unit 3, which is imaged on the second surface 102 by the condenser lens 4, it can be seen that the minimum angle between the incident light ray that passes through the condenser lens 4 and the light-transmitting substrate 1 and arrives at the second surface 102 and the normal of the second surface 102 is... Figure 2 The incident angle α satisfies the following formula:

[0071] (1)

[0072] (2)

[0073] (3) M = tanβ(h + b);

[0074] (4)

[0075] Wherein, D is the maximum width of the light-emitting area 3a of the light-emitting element 31 in the direction parallel to the second surface 102; L is the aperture of the condenser lens 4; h is the distance between the surface of the light-emitting element 31 facing the condenser lens 4 and the optical center O of the condenser lens 4 in the direction perpendicular to the second surface 102; b is the thickness of the light-transmitting substrate 1 in the direction perpendicular to the second surface 102; X is the distance between the geometric center of the orthographic projection of the light-emitting element 31 on the second surface 102 and the orthographic projection of the principal optical axis CC of the condenser lens 4 on the second surface 102 in the direction parallel to the second surface 102.

[0076] From formulas (1) to (4), we can derive the following:

[0077] When the incident angle α is greater than the critical angle θ for total internal reflection of the light on the second surface 102, the light emitted by the light-emitting element 31 and incident on the light-transmitting substrate 1 through the condenser lens 4 can achieve total internal reflection. With this configuration, it is possible to control that the angle α between all the light rays emitted from the light-emitting area 3a of the light-emitting element 31 and the normal of the second surface 102 is greater than the critical angle for total internal reflection, so that the light emitted from the light-emitting area 3a of the light-emitting element 31 achieves total internal reflection when incident on the second surface 102.

[0078] In some embodiments, α > 40°. When the light-transmitting substrate 1 is made of glass or a glass-like material, the critical angle for total internal reflection of light on the second surface is approximately 42°. Setting α to satisfy the above relationship allows most of the light rays incident from the light-emitting element 31 onto the light-transmitting substrate 1 via the condenser lens 4 to achieve total internal reflection at the second surface. Furthermore, in this embodiment, the values ​​of D, L, h, b, and X can be adjusted to make α greater than the critical angle for total internal reflection, thereby achieving total internal reflection.

[0079] In some embodiments, the distance X between the geometric center of the orthographic projection of any light-emitting element 31 on the second surface 102 and the orthographic projection of the principal optical axis CC of the corresponding condenser lens 4 on the second surface 102 is equal to L / 4. To ensure the light emission efficiency of the light-emitting unit 3, the width D of the light-emitting element 31 and the aperture L of the condenser lens 4 are usually fixed values. In this case, α can be adjusted by adjusting h and b. Furthermore, considering that an excessively thick transparent substrate 1 would affect the overall thickness of the light-emitting substrate and hinder its thinning, the value of h can be adjusted to change the value of α. In some embodiments, the value of h ranges from 10 μm to 30 μm. In one example, D is 10 μm, L is 150 μm, h is 30 μm, and b is 500 μm.

[0080] In some embodiments, such as Figure 2 As shown, the light-emitting substrate also includes a filling layer 5 located between the condenser lens 4 and the light-emitting element 31. The refractive index of the filling layer 5 is less than that of the condenser lens 4. With this configuration, when the light emitted from the light-emitting region 3a of the light-emitting unit 3 passes through the interface between the filling layer 5 and the condenser lens 4, light reflection can be avoided, allowing more light to pass through the interface between the filling layer 5 and the condenser lens 4 and enter the condenser lens.

[0081] In some embodiments, at least a portion of the second reflective layer 8 is disposed on the side of the filling layer 5 away from the light-transmitting substrate 1 and is in contact with the filling layer 5.

[0082] In other embodiments, at least a portion of the second reflective layer 8 is disposed on the side of the filling layer 5 so that light rays reflected by the first reflective layer 2 that strike the side of the filling layer 5 are utilized by secondary reflection (not shown in the figure).

[0083] In some embodiments, the filler layer 5 can be made of any one of epoxy resin, silicone, polymethyl methacrylate (PMMA), etc.

[0084] In some embodiments, the height of the filling layer 5 in the third z-direction is greater than the height of the light-emitting unit 3 in the third z-direction. In other embodiments, the height of the filling layer 5 in the third z-direction is equal to the height of the light-emitting unit 3 in the third z-direction. In still other embodiments, the height of the filling layer 5 in the third z-direction is equal to the height of the light-emitting unit 3 in the third z-direction.

[0085] In some embodiments, the surface of the first reflective layer 2 facing the light-transmitting substrate 1 is provided with a plurality of spaced-apart light-collecting structures 7. The light-collecting structures 7 can disperse the light incident on the first reflective layer 2 so that it is scattered in various directions. Specifically, the light reflected by the second surface 102 is dispersed by the light-collecting structures 7 after it is incident on the first reflective layer 2, changing the propagation direction of the light, and after being reflected by the first reflective layer 2, it is emitted through the second surface 102 of the light-transmitting substrate 1, which can improve the brightness uniformity of the light-emitting substrate.

[0086] In some embodiments, such as Figure 2 As shown, the light-emitting substrate also includes a plurality of microstructures 11 located on the side of the light-transmitting substrate 1 facing the first reflective layer 2. The light-collecting structure 7 is a first protrusion 71, and the microstructure 11 is a recessed structure 111. Each first protrusion 71 is located in the corresponding recessed structure 111. The recessed structure 11 can be provided on the first surface of the light-transmitting substrate 1.

[0087] In some embodiments, when the light-collecting structure 7 is a first protrusion 71, the material of the light-collecting structure 7 is a reflective material or a scattering material. In some examples, the material of the light-collecting structure 7 is a metal, preferably, the material of the light-collecting structure 7 includes at least one of aluminum, silver, copper, and platinum. In other examples, the material of the light-collecting structure includes a matrix and scattering particles coated by the matrix. The matrix may include at least one of polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), and epoxy resin. The scattering particles may include at least one of titanium dioxide (TiO2), alumina (Al2O3), silicon dioxide (SiO2), polystyrene microspheres, and metal nanoparticles.

[0088] In this embodiment, the first surface 101 is made into an uneven surface by combining multiple spaced first protrusions 71 with the first reflective layer 2, so that the light irradiated on the surface of the first reflective layer 2 facing the light-transmitting substrate 1 is scattered and dispersed in all directions, so that the reflected light is uniformly emitted through the second surface 102.

[0089] In some embodiments, the first reflective layer 2 and the light-collecting structure 7 are made of the same material. Preferably, the first reflective layer 2 and the light-collecting structure 7 are integrally formed.

[0090] In other embodiments, the material of the light-collecting structure 7 is different from the material of the first reflective layer 2.

[0091] In other embodiments, such as Figure 3 and Figure 4As shown, the light-collecting structure 7 is a recessed portion 72, and the microstructure 11 includes a plurality of second protrusions 112 arranged at intervals on the first surface 101 of the light-transmitting substrate 1, with each second protrusion 112 located within a recessed portion 72. Similar to the aforementioned embodiment, this allows light to be uniformly emitted after reflection by the first reflective layer 2. The recessed portion 72 is located on the surface of the first reflective layer 2 facing the light-transmitting substrate 1.

[0092] In some embodiments, when the light-collecting structure 7 is a recess 72, the material of the light-collecting structure 7 is a reflective material. In some examples, the material of the light-collecting structure 7 is a metal, preferably, the material of the light-collecting structure 7 includes at least one of aluminum, silver, copper and platinum.

[0093] In some embodiments, the shape of the first protrusion 71 or the recess 72 may be approximately one of a cone, a pyramid, and a spherical cap. "Approximately cone and pyramid" means that it is generally cone-shaped or pyramidal, but is not limited to standard cones and pyramids. That is, "cone and pyramidal" here includes not only the shapes of basic cones and pyramids, but also shapes similar to cones and pyramids. For example, the apex of a cone or pyramid is a curved surface. "Approximately spherical cap" means that it is generally spherical cap, but is not limited to a standard spherical cap. That is, "spherical cap" here includes not only the shape of a basic spherical cap, but also shapes similar to spherical caps. For example, the upper half of a spherical cap is a standard spherical cap, and the lower half is a cylinder.

[0094] In some embodiments, all incident light rays from the light-emitting element 31 incident on the second surface 102 via the condenser lens 4 form an imaging area (the area where the image is located) on the second surface 102 of the light-transmitting substrate 1. The orthographic projection of the imaging area on the second surface 102 falls within the area enclosed by the orthographic projection of the light-collecting structure 7 on the second surface 102. The second surface 102 of the light-transmitting substrate 1 also includes a region surrounded by the imaging area. Since the imaging area of ​​the light emitted by the light-emitting element 31 on the second surface 102 is located in the side region, if the light-collecting structure 7 is not provided, the brightness of the region surrounded by the imaging area is relatively small, affecting the brightness uniformity of the light-emitting substrate. The light-collecting structure 7 can increase the amount of light incident on the region surrounded by the imaging area, reducing the brightness difference between different regions of the second surface.

[0095] Furthermore, the density of the light-collecting structure 7 corresponding to the imaging area is greater than the density of the light-collecting structure 7 corresponding to the area surrounded by the imaging area. This further improves the light emission uniformity of the light-emitting substrate.

[0096] In some embodiments, such as Figure 5As shown, the light-emitting substrate includes a first light-collecting area 7a and a second light-collecting area 7b arranged sequentially in a direction away from the lens. Both the first light-collecting area 7a and the second light-collecting area 7b are provided with multiple light-collecting structures 7. The distribution density of the light-collecting structures 7 in the first light-collecting area 7a is greater than that in the second light-collecting area 7b. With this arrangement, the amount of light emitted from different areas can be adjusted by changing the distribution density of the first protrusion 71 or the recess 72. This increases the difference in brightness between the light passing through the area surrounded by the imaging area and the light passing through the imaging area, thereby further improving the brightness uniformity of the light emitted from the second surface 102.

[0097] In other embodiments, the light-collecting structure 7 of the first light-collecting area 7a and the light-collecting structure 7 of the second light-collecting area 7b have the same density, and the size of the light-collecting structure 7 of the first light-collecting area 7a is larger than the size of the light-collecting structure 7 of the second light-collecting area 7b. With this configuration, the light emission angle can be adjusted by adjusting the size of the first protrusion 71 or the recess 72.

[0098] In some embodiments, the condenser lens 4 is a convex lens. Further, the condenser lens 4 includes a third surface facing the light-emitting element 31 and a fourth surface facing the light-transmitting substrate 1, at least one of the third and fourth surfaces being a curved surface. In one embodiment, such as Figure 2 As shown, the third surface is curved. In another embodiment, the fourth surface is curved. In yet another embodiment, both the third and fourth surfaces are curved.

[0099] In some embodiments, such as Figure 6 As shown, the condenser lens 4 is a Fresnel lens. Furthermore, the surface of the condenser lens 4 facing the light-emitting element 31 is a Fresnel surface.

[0100] In some embodiments, such as Figure 7 As shown, the focusing lens 4 is a metasurface lens. The lens comprises multiple spaced-apart nanostructure units. This application also provides a display device, including a light-emitting substrate as provided in the foregoing embodiments.

[0101] In one embodiment, the display device further includes a display panel located on the side of the substrate away from the light-emitting element. The display panel may be a liquid crystal display device, and the light-emitting substrate may serve as a backlight module.

[0102] This application does not impose specific limitations on the application of display devices, which can be any product or component with flexible display function, such as televisions, laptops, tablets, wearable display devices, mobile phones, in-vehicle displays, navigation systems, e-books, digital photo frames, and advertising light boxes.

[0103] It should be understood that the embodiments described herein should be considered in a descriptive sense only and not for limiting purposes. The description of features or aspects within each embodiment should generally be considered as other similar features or aspects that may be used in other embodiments. Although one or more embodiments have been described with reference to the accompanying drawings, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope defined by the claims and their equivalents.

Claims

1. A light-emitting substrate, characterized in that, include: A light-transmitting substrate, comprising a first surface and a second surface opposite to each other; A first reflective layer is located on the side of the light-transmitting substrate away from the second surface, and the first reflective layer has at least one through hole; The light-emitting unit is located on the same side of the light-transmitting substrate as the first reflective layer, and the light-emitting unit includes at least one light-emitting element; A condensing lens is located between the light-transmitting substrate and the light-emitting unit, and the condensing lens converges the light emitted by the light-emitting unit; the orthographic projection of the principal optical axis of each condensing lens on the second surface lies within the orthographic projection of a through hole on the second surface; one light-emitting unit is opposite to one condensing lens, and the orthographic projection of the light-emitting area of ​​each light-emitting element of the light-emitting unit on the second surface overlaps with the orthographic projection of the corresponding condensing lens on the second surface; the orthographic projection of the light-emitting area of ​​each light-emitting element of the light-emitting unit on the second surface does not overlap with the orthographic projection of the principal optical axis of the corresponding condensing lens on the second surface.

2. The light-emitting substrate according to claim 1, characterized in that, In a direction perpendicular to the second surface, the distance between the surface of the light-emitting element facing the condenser lens and the optical center of the condenser lens is h, where 10μm≤h≤30μm.

3. The light-emitting substrate according to claim 1, characterized in that, The light-emitting unit includes a plurality of light-emitting elements, and the orthographic projections of the plurality of light-emitting elements of the same light-emitting unit on the second surface surround the orthographic projections of the principal optical axis of the corresponding condenser lens on the second surface.

4. The light-emitting substrate according to claim 3, characterized in that, The distance between the geometric center of the orthographic projection of each of the light-emitting elements on the second surface and the orthographic projection of the principal optical axis of the condensing lens on the second surface is the same.

5. The light-emitting substrate according to claim 3, characterized in that, The number of light-emitting elements in the light-emitting unit is 4.

6. The light-emitting substrate according to claim 3, characterized in that, The light-emitting unit comprises a plurality of light-emitting elements connected in series.

7. The light-emitting substrate according to claim 1, characterized in that, Wherein, D is the maximum width of the light-emitting area of ​​the light-emitting element in the direction parallel to the second surface, L is the aperture of the condensing lens, h is the distance between the surface of the light-emitting element facing the condensing lens and the optical center O of the condensing lens in the direction perpendicular to the second surface, b is the thickness of the light-transmitting substrate in the direction perpendicular to the second surface, and X is the distance between the geometric center of the orthographic projection of the light-emitting element on the second surface and the orthographic projection of the principal optical axis of the condensing lens on the second surface in the direction parallel to the second surface.

8. The light-emitting substrate according to claim 1, characterized in that, The light-emitting substrate further includes a filling layer located between the condensing lens and the light-emitting element, and the filling layer is made of any one of epoxy resin, silicone, and polymethyl methacrylate.

9. The light-emitting substrate according to claim 1, characterized in that, The first reflective layer has multiple light-collecting structures arranged at intervals on its surface facing the light-transmitting substrate.

10. The light-emitting substrate according to claim 9, characterized in that, The light-emitting substrate further includes a plurality of microstructures located on the side of the light-transmitting substrate facing the first reflective layer, wherein, The light-collecting structure is a first protrusion, and the microstructure is a recessed structure, with each first protrusion located within a corresponding recessed structure; or... The light-collecting structure is a recessed portion, and the microstructure is a second protrusion, with each recessed portion covering the corresponding second protrusion.

11. The light-emitting substrate according to claim 1, characterized in that, The focusing lens is a convex lens, a Fresnel lens, or a metasurface lens.

12. The light-emitting substrate according to claim 11, characterized in that, When the condensing lens is a convex lens, the condensing lens includes a third surface facing the light-emitting element and a fourth surface facing the light-transmitting substrate, and at least one of the third surface and the fourth surface is a curved surface.

13. The light-emitting substrate according to claim 1, characterized in that, The light-emitting substrate further includes a second reflective layer, which covers the surface of each light-emitting element away from the condenser lens.

14. The light-emitting substrate according to claim 13, characterized in that, The material of the second reflective layer includes at least one of white ink and silicone-based white glue.

15. A display device, characterized in that, Includes the light-emitting substrate as described in any one of claims 1 to 14.

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