Light-emitting element and display device

Abstract

The present invention discloses a light-emitting element and a display device. A metal reflective structure is arranged between a retaining wall structure and a light-emitting unit. Since the side wall (reflective surface) of the first hollow structure of the metal reflective structure is arranged at an angle relative to the light-emitting surface of the light-emitting unit, when the divergent light emitted by the light-emitting unit is incident on the side wall (reflective surface) of the first hollow structure, the side wall (reflective surface) of the first hollow structure can cause more light to be directed onto the quantum point color conversion film, thereby greatly improving the utilization rate of light and obtaining a light-emitting element with high light efficiency.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a light-emitting element and a display device. Background Art

[0002] The luminescence spectrum of quantum dot (QD) material has a very narrow half-peak width. Therefore, QD has potential application value in the field of photoluminescent display and electroluminescent display. LED (a display combining quantum dots and inorganic light-emitting diode technology) is a typical representative of QD material photoluminescent display, but the most common QD The luminous efficiency of LED devices is low. Summary of the Invention

[0003] Embodiments of the present invention provide a light-emitting element and a display device, which are used to improve the light-emitting efficiency of the light-emitting element.

[0004] An embodiment of the present invention provides a light-emitting element, including:

[0005] substrate;

[0006] A plurality of light-emitting units are located on the base substrate;

[0007] a metal reflective structure located on a side of the light-emitting unit facing away from the base substrate; the metal reflective structure having a plurality of first hollow structures, the orthographic projection of the light-emitting unit on the base substrate being located within the orthographic projection range of the first hollow structures on the base substrate, and sidewalls of the first hollow structures being arranged obliquely relative to the light-emitting surface of the light-emitting unit;

[0008] a retaining wall structure located on a side of the metal reflective structure facing away from the base substrate; the retaining wall structure having a plurality of sub-pixel openings, the first hollow structures corresponding one-to-one to the sub-pixel openings, and an orthographic projection of the first hollow structure on the base substrate being located within the orthographic projection range of the sub-pixel openings on the base substrate;

[0009] A plurality of quantum dot color conversion films are provided, wherein at least a portion of the sub-pixel openings are provided with the quantum dot color conversion films.

[0010] Optionally, the light-emitting element provided in the embodiment of the present invention further includes a connection layer located between the metal reflective structure and the retaining wall structure, and the connection layer fills the first hollow structure.

[0011] Optionally, in the above-mentioned light-emitting element provided by an embodiment of the present invention, the metal reflective structure includes a plurality of reflective parts independently arranged around each of the light-emitting units, the reflective parts have the first hollow structure, and the connecting layer also fills the gaps between adjacent reflective parts.

[0012] Optionally, in the above-mentioned light-emitting element provided by an embodiment of the present invention, the reflective portion includes a body and a reflective layer located between the body and the connecting layer, the material of the body includes resin, and the material of the reflective layer includes ITO / Ag / ITO.

[0013] Optionally, in the above-mentioned light-emitting element provided by an embodiment of the present invention, a cross-sectional shape of the body along the thickness direction of the base substrate is a triangle, and an inner angle of the triangle pointing to the light-emitting unit is an acute angle.

[0014] Optionally, in the above-mentioned light-emitting element provided by an embodiment of the present invention, the sum of the inner angle and the light-emitting angle of the light-emitting unit is less than 90°.

[0015] Optionally, the above-mentioned light-emitting element provided in an embodiment of the present invention further includes a metal wire grid polarizer located on the side of the multiple quantum dot color conversion films away from the base substrate, the metal wire grid polarizer includes a cover plate and a metal wire grid located on the side of the cover plate away from the base substrate; the metal wire grid includes a plurality of metal wires arranged in parallel and spaced apart.

[0016] Optionally, in the above-mentioned light-emitting element provided by an embodiment of the present invention, the period of the metal wire grid is less than or equal to 120 nm, the height of the metal wire is greater than or equal to 140 nm, and the duty cycle of the metal wire grid is 0.35-0.5.

[0017] Optionally, the above-mentioned light-emitting element provided in an embodiment of the present invention further includes a metal bonding layer located between the connecting layer and the retaining wall structure; the metal bonding layer has a plurality of second hollow structures and a metal bonding portion located between adjacent second hollow structures, and the orthographic projection of the metal bonding portion on the base substrate coincides with the orthographic projection of the retaining wall structure on the base substrate.

[0018] Optionally, in the above-mentioned light-emitting element provided by an embodiment of the present invention, the metal bonding portion includes a first Cu layer, an In layer, and a second Cu layer that are stacked.

[0019] Optionally, in the above-mentioned light-emitting element provided by an embodiment of the present invention, the first Cu layer and the second Cu layer have the same thickness, and the ratio of the thickness of the first Cu layer to the thickness of the In layer is greater than 1.2:1.

[0020] Optionally, the light-emitting element provided in the embodiment of the present invention further includes a planar layer filling the second hollow structure.

[0021] Optionally, the light-emitting element provided in the embodiment of the present invention further includes a quantum dot encapsulation layer located between the metal bonding layer and the retaining wall structure, and the quantum dot encapsulation layer covers the base substrate in an orthographic projection on the base substrate.

[0022] Optionally, in the above-mentioned light-emitting element provided by an embodiment of the present invention, the material of the retaining wall structure is a reflective material.

[0023] Optionally, in the above-mentioned light-emitting element provided in an embodiment of the present invention, the light-emitting color of the light-emitting unit is blue, the sub-pixel opening includes a first sub-pixel opening, a second sub-pixel opening and a third sub-pixel opening, the red quantum dot color conversion film is arranged in the first sub-pixel opening, the green quantum dot color conversion film is arranged in the second sub-pixel opening, and the third sub-pixel opening is filled with resin material, and the resin material contains scattering particles.

[0024] Optionally, the above-mentioned light-emitting element provided in an embodiment of the present invention further includes a light-shielding layer and a color filter layer located between the retaining wall structure and the cover plate, the light-shielding layer has a plurality of through holes corresponding one-to-one to the sub-pixel openings, and the color filter layer includes a plurality of color resists, and the color resists correspond one-to-one to the quantum dot color conversion film and are respectively located in each of the through holes.

[0025] Optionally, in the above-mentioned light-emitting element provided by an embodiment of the present invention, the light-emitting unit includes Mini LED or Micro LED.

[0026] Correspondingly, an embodiment of the present invention further provides a display device, comprising any one of the above-mentioned light-emitting elements provided by the embodiment of the present invention.

[0027] The beneficial effects of the embodiments of the present invention are as follows:

[0028] An embodiment of the present invention provides a light-emitting element and a display device. A metal reflective structure is provided between a retaining wall structure and a light-emitting unit. Since the side wall (reflective surface) of the first hollow structure of the metal reflective structure is inclined relative to the light-emitting surface of the light-emitting unit, when the divergent light emitted by the light-emitting unit is incident on the side wall (reflective surface) of the first hollow structure, the side wall (reflective surface) of the first hollow structure can cause more light to be directed toward the quantum point color conversion film, thereby greatly improving the utilization rate of light and obtaining a light-emitting element with high light efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic structural diagram of a light-emitting element provided by an embodiment of the present invention;

[0030] Figure 2 A schematic structural diagram of another light-emitting element provided by an embodiment of the present invention;

[0031] Figure 3 A schematic structural diagram of another light-emitting element provided by an embodiment of the present invention;

[0032] Figure 4 for Figure 2 Schematic diagram of the local structure;

[0033] Figure 5 Schematic diagram of several reflection paths of light emitted by the light-emitting unit and incident on the metal wire grid polarizer;

[0034] Figure 6A Schematic diagram of transmission type metal wire grid polarization;

[0035] Figure 6B This is a plan view of the WGP;

[0036] Figure 6C is the reflection path A1 of the TE wave;

[0037] Figure 6D and Figure 6E The top view of two types of reflected light;

[0038] Figure 7A for Figure 5 A schematic plan view of the reflection path A2;

[0039] Figure 7B A top view of the reflected light;

[0040] Figure 8 for Figure 1 、 Figure 2 and Figure 3 Schematic diagrams of the corresponding three sub-pixel openings;

[0041] Figure 9 For multiple Figure 8 Schematic diagram of the repeating arrangement of the structure shown;

[0042] Figure 10A and Figure 10B Schematic diagrams of brightness conversion corresponding to thickness changes of red quantum dot color conversion films and green quantum dot color conversion films;

[0043] Figure 11A for Figure 1-Figure 3 Schematic diagram of the structure of the metal wire grid polarizer (WGP);

[0044] Figure 11B Schematic diagram of the relationship between the extinction ratio and wavelength of WGP at different wire grating periods;

[0045] Figure 11C Schematic diagram of the relationship between the duty cycle, extinction ratio, and TM polarization transmittance of WGP;

[0046] Figure 11D Schematic diagram of the relationship between the groove depth, transmittance, and extinction ratio of WGP;

[0047] Figure 11E Schematic diagram of the relationship between the wire grid period of the metal wire grid, the height of the metal wires, and the polarization degree of the metal wire grid polarizer;

[0048] Figure 12 Schematic diagram of the relationship between the duty cycle of WGP and the transmittance and polarization degree;

[0049] Figure 13 Schematic diagram of the structure of the metal reflective structure, connecting layer and light-emitting unit made on the sapphire substrate;

[0050] Figures 14A-14M A schematic diagram of the structure of the method for manufacturing a light-emitting element according to an embodiment of the present invention after performing each step;

[0051] Figure 15 A schematic structural diagram of a display device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. And in the absence of conflict, the embodiments in the present disclosure and the features in the embodiments can be combined with each other. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0053] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the usual meanings understood by persons of ordinary skill in the field to which this disclosure belongs. The words “include” or “comprise” and the like used in this disclosure mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. The words “connect” or “connected” and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Inside”, “outside”, “upper”, “lower”, etc. are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0054] It should be noted that the sizes and shapes of the figures in the accompanying drawings do not reflect the actual scale and are only for the purpose of illustrating the present disclosure. The same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions.

[0055] The embodiment of the present invention provides a light emitting element, such as Figure 1 Shown, including:

[0056] Base substrate 1;

[0057] A plurality of light-emitting units 2 are located on the base substrate 1;

[0058] The metal reflective structure 3 is located on the side of the light-emitting unit 2 facing away from the base substrate 1. The metal reflective structure 3 has multiple first hollow structures 301. The orthographic projection of the light-emitting unit 2 on the base substrate 1 is located within the orthographic projection range of the first hollow structures 301 on the base substrate 1. The sidewalls 31 (reflective surfaces) of the first hollow structures 301 are arranged at an angle relative to the light-emitting surface 21 of the light-emitting unit 2.

[0059] The retaining wall structure 4 is located on a side of the metal reflective structure 3 facing away from the base substrate 1; the retaining wall structure 4 has a plurality of sub-pixel openings (41, 42, 43), the first hollow structure 301 corresponds to the sub-pixel openings (41, 42, 43) one-to-one, and the orthographic projection of the first hollow structure 301 on the base substrate 1 is located within the orthographic projection range of the corresponding sub-pixel openings (41, 42, 43) on the base substrate 1;

[0060] A plurality of quantum dot color conversion films 5 , wherein at least a portion of the sub-pixel openings (eg 41 and 42 ) are provided with a quantum dot color conversion film 5 .

[0061] The above-mentioned light-emitting element provided by an embodiment of the present invention is configured by arranging a metal reflective structure between the retaining wall structure and the light-emitting unit. Since the side wall (reflective surface) of the first hollow structure of the metal reflective structure is arranged at an angle relative to the light-emitting surface of the light-emitting unit, when the divergent light emitted by the light-emitting unit is incident on the side wall (reflective surface) of the first hollow structure, the side wall (reflective surface) of the first hollow structure can allow more light to be directed toward the quantum point color conversion film, thereby greatly improving the utilization rate of light and obtaining a light-emitting element with high light efficiency.

[0062] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 1 As shown, a connection layer 6 is further included between the metal reflective structure 3 and the retaining wall structure 4, and the connection layer 6 fills the first hollow structure 301. Specifically, the material of the connection layer 6 can be GaN.

[0063] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 1As shown, the metal reflective structure 3 may include a plurality of reflective portions 32 independently arranged around each light emitting unit 2 , the reflective portion 32 having a first hollow structure 301 , and the connecting layer 6 also fills the gaps between adjacent reflective portions 32 to ensure the flatness of subsequent film layers.

[0064] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 1 As shown, the entire reflective portion 32 can be made of a reflective metal material, such as Ag, Al, Mo, etc.

[0065] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 2 As shown, the reflective portion 32 may include a main body 321 and a reflective layer 322 located between the main body 321 and the connecting layer 6. The material of the main body 321 may include resin, and the material of the reflective layer 322 may be ITO / Ag / ITO, ITO / Al / ITO, ITO / Mo / ITO, etc.

[0066] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 2 As shown, the cross-sectional shape of the main body 321 along the thickness direction of the base substrate 1 can be a triangle, and the internal angle β of the triangle pointing to the light-emitting unit 2 is an acute angle, thereby ensuring that the reflective layer 322 is a slope, so that the light emitted by the light-emitting unit 2 is reflected to the quantum dot color conversion film 5 when it enters the reflective layer 322, thereby improving the utilization efficiency of the light.

[0067] It should be noted that the embodiments of the present invention Figure 2 The cross-sectional shape of the body 321 along the thickness direction of the base substrate 1 is a triangle as an example. Of course, it is not limited to this, as long as the reflective layer 322 can be tilted relative to the light-emitting surface of the light-emitting unit 2.

[0068] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 1 and Figure 2 As shown, the metal reflective structure 3 is taken as an example including a plurality of reflective parts 32 independently arranged around each light emitting unit 2. Of course, the metal reflective structure 3 can also be a grid structure, such as Figure 3 As shown, the first hollow structure 301 is a mesh of a grid-like structure, and the side wall (reflective surface) of the mesh is inclined relative to the light-emitting surface of the light-emitting unit 2.

[0069] It should be noted that Figure 3 The metal reflective structure 3 can be made of a reflective metal material as a whole, or can be a body including a resin material, the body having a first hollow structure, and then a reflective layer is made on the side wall of the first hollow structure of the body.

[0070] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 1 、 Figure 2 and Figure 3 As shown, the structure further includes a wire grid polarizer 7 (WGP) located on the side of the multiple quantum dot color conversion films 5 facing away from the base substrate 1. The wire grid polarizer 7 includes a cover plate 71 and a wire grid 72 located on the side of the cover plate 71 facing away from the base substrate 1. The wire grid 72 includes a plurality of metal wires 721 arranged in parallel and spaced relation. Specifically, when light emitted by the light-emitting unit 2 is incident on the wire grid polarizer 7, the incident light can be decomposed into light with a vibration direction parallel to the transmission direction (TM light perpendicular to the metal wires) and light with a vibration direction perpendicular to the transmission direction (TE light parallel to the metal wires). The TM wave is emitted, and the TE wave is reflected below the cover plate 71. For example, the TE wave is reflected onto the inclined surface of the quantum dot color conversion film 5 or the metal reflective structure 3, becoming secondary excitation light, which greatly improves the utilization rate of light and achieves high light efficiency.

[0071] Specifically, the cover plate 71 may be a glass substrate.

[0072] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 1 、 Figure 2 and Figure 3 As shown, the metal bonding layer 8 is further included between the connecting layer 6 and the retaining wall structure 4. The metal bonding layer 8 has a plurality of second hollow structures 801 and metal bonding portions 81 located between adjacent second hollow structures 801. The orthographic projection of the metal bonding portion 81 on the base substrate 1 coincides with the orthographic projection of the retaining wall structure 4 on the base substrate 1. Specifically, the metal bonding layer 8 not only serves as a connection, but also as a reflective layer. For example, when light reflected from the metal wire grid polarizer 7 is incident on the metal bonding layer 8, the metal bonding layer 8 can reflect the light to the quantum dot color conversion film 5 for excitation, further obtaining more excitation light and improving luminous efficiency.

[0073] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 1 、 Figure 2 and Figure 3 As shown, the metal bonding portion 81 may include a stacked first Cu layer 811, an In layer 812, and a second Cu layer 813. Specifically, the first Cu layer 811 and the second Cu layer 813 primarily serve to reflect and connect the upper and lower film layers, and the In layer 812 primarily serves to connect the first Cu layer 811 and the second Cu layer 813.

[0074] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 1 、 Figure 2 and Figure 3 As shown, the thickness of the first Cu layer 811 and the second Cu layer 813 can be the same, and the ratio of the thickness of the first Cu layer 811 to the thickness of the In layer 812 can be greater than 1.2:1, so that the first Cu layer 811 and the second Cu layer 813 have a larger reflection surface, further improving the light utilization rate.

[0075] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 1 、 Figure 2 and Figure 3 As shown, it also includes a flat layer 9 filling the second hollow structure 801 . The thickness of the flat layer 9 is the same as that of the metal bonding portion 81 . The material of the flat layer 9 can be resin.

[0076] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 1 、 Figure 2 and Figure 3 As shown, the device further includes a quantum dot encapsulation layer 10 located between the metal bonding layer 8 and the retaining wall structure 4. The quantum dot encapsulation layer 10 orthographically covers the base substrate 1. This quantum dot encapsulation layer 10 is used to block external moisture and protect the quantum dot material in the quantum dot color conversion film 5 from contact with water, oxygen, and the like, thereby improving the stability and lifespan of the device. Specifically, the material of the quantum dot encapsulation layer 10 can be SiON.

[0077] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 2 and Figure 4 As shown, Figure 4 for Figure 2 Schematic diagram of a partial structure of , the sum of the internal angle β and the emission angle α of the light-emitting unit 2 is less than 90°. Specifically, the emission angle α of the light-emitting unit 2 refers to the angle between the light emitted by the light-emitting unit 2 and the normal L perpendicular to the light-emitting unit 2. At this time, the light emitted by the light-emitting unit 2 with an angle greater than α will be reflected by the reflective layer 322 and can enter the quantum dot color conversion film 5 for excitation, thereby obtaining more excitation light.

[0078] like Figure 4As shown, the area of ​​the light-emitting unit 2 is S1, the area of ​​the quantum dot color conversion film 5 is S2, and the angular spectrum of the light-emitting angle α of the light-emitting unit 2 ranges from -90° to +90°. The area S1 of the light-emitting unit 2, the area S2 of the quantum dot color conversion film 5, and the height (e.g., 10.32 μm) of the intermediate film layers (connection layer 6, planarization layer 9, and quantum dot encapsulation layer 10) determine the angles at which light enters the quantum dot color conversion film 5. In the metal bonding layer 8, for example, the thickness of the first and second Cu layers is 2 μm, and the thickness of the In layer is 1.32 μm. That is, the thickness of the metal bonding layer 8 is 5.32 μm, the thickness of the connection layer 6 is 4 μm, the thickness of the quantum dot encapsulation layer 10 is 1 μm, and the thickness of the planarization layer 9 is the same as that of the metal bonding layer 8. When S2=50μm×50μm, S1=20μm×20μm, the luminous angle α incident on the quantum dot color conversion film 5 is ±56.3°. α should be as large as possible so that more light emitted by the light-emitting unit 2 enters the quantum dot color conversion film 5, thereby improving light utilization.

[0079] In specific implementation, among the above-mentioned light-emitting elements provided in the embodiment of the present invention, such as 2 and Figure 4 As shown, since the cross-sectional shape of the main body 321 of the reflective portion 32 along the thickness direction of the base substrate 1 is a triangle, the internal angle β in the triangle pointing to the light-emitting unit 2 is an acute angle, and the sum of the internal angle β and the light-emitting angle α of the light-emitting unit 2 is less than 90°. Assuming that the light-emitting angle α=56.3°, that is, β<90°-α must be satisfied, then the light emitted by the light-emitting unit 2 with an angle greater than α will be reflected by the reflective layer 322, and can enter the quantum dot color conversion film 5 for excitation, thereby obtaining more excitation light.

[0080] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 1 、 Figure 2 and Figure 3 As shown, the material of the retaining wall structure 4 can be a reflective material. In this way, when the light emitted by the light-emitting unit 2 is incident on the retaining wall structure 4, it can be reflected back. On the one hand, it can prevent the light from penetrating the retaining wall structure 4 and entering the adjacent sub-pixel opening, thereby further avoiding the problem of light crosstalk; on the other hand, the light incident on the retaining wall structure 4 can be reflected back, thereby achieving the effect of enhancing light output while avoiding light crosstalk.

[0081] Optionally, the material of the retaining wall structure 4 may be KW-8826 (high acid value resin), which has a reflectivity of up to 56% for 550 nm light.

[0082] like Figure 5 As shown, Figure 5 For Figure 1Taking a light-emitting unit 2 in the structure shown as an example, several possible reflection paths of the light emitted by the light-emitting unit 2 and incident on the metal wire grid polarizer 7 are described. The light incident on the metal wire grid polarizer 7 is emitted as a TM wave, and the TE wave may be reflected to the quantum dot color conversion film 5, the inclined surface of the metal reflective structure 3 or the first Cu layer and the second Cu layer of the metal bonding layer 8, becoming secondary excitation light, which greatly improves the utilization rate of light and obtains high light efficiency; among them, path A1 is the TE wave reflected to the quantum dots in the quantum dot color conversion film 5 and then excites the quantum dots to emit light again; path A2 is the T The E wave is reflected by the Cu layer of the metal bonding layer 8, and then reflected by the Cu layer to the retaining wall structure 4. The retaining wall structure 4 reflects the incident light to the quantum dot color conversion film 5, which again excites the quantum dots to emit light. Path A3 is the TE wave reflected by the inclined surface of the metal reflective structure 3, and then reflected by the inclined surface of the metal reflective structure 3 to the retaining wall structure 4. The retaining wall structure 4 reflects the incident light to the quantum dot color conversion film 5, which again excites the quantum dots to emit light. Due to the provision of the metal wire grid polarizer 7, at least three reflection paths are added, allowing more light to re-excite the quantum dot color conversion film 5, greatly improving the light efficiency utilization rate. Therefore, the embodiment of the present invention can obtain a high-light-efficiency light-emitting element through the interaction of the metal wire grid polarizer 7, the inclined surface of the metal reflective structure 3, and the metal bonding layer 8.

[0083] Below Figure 5 The reflection path A1 shown in FIG. 1 is used to describe the reuse of light in detail. Figures 6A-6C As shown, Figure 6A Schematic diagram of transmission type metal wire grid polarization. Figure 6B This is a schematic diagram of the WGP. Figure 6C The reflection path A1 of the TE wave is shown. It can be seen that the polarization direction is perpendicular to the paper surface (TE wave) and encounters the quantum dots in the quantum dot color conversion film (taking the light propagating downward as an example, there are also other light propagating downward in other directions). Since the reflection surface is a sphere, the polarization state of the reflected light is no longer perpendicular to the paper surface, but forms a certain angle with the paper surface. There is a component in the TM wave direction, which can be partially emitted when encountering the WGP, such as Figure 6D and Figure 6E As shown, Figure 6D and Figure 6E This is a top view of two types of reflected light. Only the polarization state of light emitted in directions abcd is still TE wave, and the polarization state of light emitted in other directions has changed. For example Figure 6D The TE wave is incident on the WGP after reflection and exits at 30° in the d direction. Assuming that the original TE wave is 1, the new exit light in the TE wave direction is cos30° 1=0.866, the TM wave direction component is cos60° 1=0.5, at this time, 0.5 component light can be emitted through WGP; Figure 6EThe TE wave is incident on the WGP after reflection and exits at 45° in the d direction. Assuming that the original TE wave is 1, the new outgoing light in the TE wave direction is cos45° 1=0.707, the TM wave direction component is cos45° 1=0.707, at this time, 0.707 component light can be emitted through WGP.

[0084] Below Figure 5 The reflection path A2 shown in FIG. 1 is used to describe the reuse of light in detail. Figure 5 、 Figure 7A and Figure 7B As shown, Figure 7A for Figure 5 From the plane diagram of the reflection path A2, it can be seen that only the polarization state of the light emitted in the four directions abcd is still TE wave, and the polarization state of the light emitted in other directions has changed. If the TE wave is incident on the WGP after reflection and the light is emitted in the direction θ° of d, and assuming that the original TE wave is 1, then the component of the new emitted light in the TE wave direction is cosθ° 1. The directional component of the TM wave is sinθ° 1. At this time, the component light with sinθ° can be emitted after passing through WGP.

[0085] It should be noted that Figure 5 The reflection path A3 is similar to the reflection path A2 and will not be described in detail.

[0086] Therefore, the light-emitting element provided in the embodiment of the present invention can obtain a light-emitting element with high light efficiency through the cooperation of the metal wire grid polarizer 7, the inclined surface of the metal reflective structure 3 and the metal bonding layer 8.

[0087] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 1 、 Figure 2 and Figure 3As shown, the luminous color of the light-emitting unit 2 can be blue, that is, the light-emitting unit 2 is a blue light source, and blue light is used as excitation light, which has a better excitation effect; the sub-pixel openings include a first sub-pixel opening 41, a second sub-pixel opening 42 and a third sub-pixel opening 43, a red quantum dot color conversion film 5 (R-QD) is set in the first sub-pixel opening 41, a green quantum dot color conversion film 5 (G-QD) is set in the second sub-pixel opening 42, and the third sub-pixel opening 43 is filled with a resin material 11, and the resin material 11 contains scattering particles (not shown). Specifically, the third sub-pixel opening 43 can directly emit blue light as a blue sub-pixel; the red quantum dots in the red quantum dot color conversion film 5 (R-QD) within the first sub-pixel opening 41 can convert the blue light into red light after being excited by blue light, becoming a red sub-pixel; the green quantum dots in the green quantum dot color conversion film 5 (G-QD) within the second sub-pixel opening 42 can convert the blue light into green light after being excited by blue light, becoming a green sub-pixel; wherein, the red quantum dot color conversion film 5 (R-QD), the green quantum dot color conversion film 5 (G-QD) and the resin material 11 can be arranged in sequence to form three-primary color sub-pixels, and the three-primary color sub-pixels constitute a pixel unit, which is cyclically and repeatedly arranged in a matrix distribution to realize a color display function.

[0088] Specifically, within the third sub-pixel opening 43, scattering particles are doped into the resin material 11, and then the resin material 11 doped with scattering particles is used to fill the recess of the third sub-pixel opening 43. The scattering particles can enhance the light emission effect and increase the light-emitting viewing angle. Optionally, the scattering particles can be made of TiO2.

[0089] In a specific implementation, in the above-mentioned light-emitting element provided in the embodiment of the present invention, as Figure 1 、 Figure 2 and Figure 3 As shown, the display further includes a light shielding layer 12 and a color filter layer 13 located between the retaining wall structure 4 and the cover plate 71. The light shielding layer 12 has multiple through holes corresponding one-to-one to the sub-pixel openings (41, 42, 43). The color filter layer 13 includes multiple color resists (R-CF, G-CF, B-CF). The color resists (R-CF, G-CF, B-CF) correspond one-to-one to the quantum dot color conversion film 5 and are located in each through hole. For example, the red quantum dot color conversion film (R-QD) corresponds to the red color group (R-CF), the green quantum dot color conversion film (G-QD) corresponds to the green color group (G-CF), and the third sub-pixel opening 23 (filled with resin material) corresponds to the blue color group (B-CF). The color resists can filter light, allowing each sub-pixel opening to emit light with higher color purity, thereby improving the display effect.

[0090] Specifically, the base substrate in the embodiment of the present invention can be a driving backplane. When the light-emitting unit 2 emits light, a driving current is input to the light-emitting unit 2 through the driving backplane. The specific light-emitting principle is the same as that of the prior art and will not be described in detail here.

[0091] Optionally, the light-emitting unit may be a Micro LED. Due to the smaller size of a Micro LED, the pixel resolution of the light-emitting element can be improved. Specifically, the size of a Micro LED is generally less than 100 μm. Of course, the light-emitting unit may also be a Mini LED or other light-emitting unit, and the present invention is not limited thereto. Specifically, when the light-emitting unit is a Mini LED, the size of the Mini LED is 100 μm-200 μm.

[0092] In specific implementation, the light-emitting element provided in the embodiment of the present invention can be a backlight source of a display device, for example, as a backlight source of a liquid crystal display device, which can improve luminous efficiency and reduce power consumption; of course, the light-emitting element provided in the embodiment of the present invention can also be directly used as a pixel structure of a display device for display.

[0093] like Figure 8 As shown, Figure 8 for Figure 1 、 Figure 2 and Figure 3 Schematic diagram of the corresponding three sub-pixel openings. Figure 8 The structure shown can be used as a repeated light-emitting unit. When the light-emitting element provided by the embodiment of the present invention is used as a backlight source of a display device, the structure of the backlight source is as follows: Figure 9 As shown, Figure 9 For multiple Figure 8 When the light emitting element provided by the embodiment of the present invention is directly used as a pixel structure of a display device for display, Figure 8 The structure shown is a pixel unit (ie, including R, G, and B sub-pixels).

[0094] In order to obtain the maximum brightness conversion rate and further improve the luminous efficiency of the light-emitting element, such as Figure 10A and Figure 10B As shown, Figure 10A and Figure 10B The following diagrams illustrate the brightness conversion corresponding to changes in film thickness for the red and green quantum dot color conversion films. It can be seen that the maximum brightness conversion rate is achieved when the film thickness of both the red and green quantum dot color conversion films reaches 20 μm. Therefore, the film thickness of the red and green quantum dot color conversion films in the embodiments of the present invention is preferably greater than 20 μm.

[0095] Specifically, if Figure 11A Show, Figure 11A for Figure 1-Figure 3 Schematic diagram of the structure of the metal wire grid polarizer 7 (WGP), wherein the wire grid period d of the metal wire grid 72 is in the range of 0 to 400 nm, the width a of the metal wire 721 is in the range of 0 to 200 nm, the height H of the metal wire 721 is greater than 100 nm, the duty cycle a / d of the metal wire grid 72 is in the range of 0 to 0.5, and the extinction ratio of the metal wire grid 72 is the ratio of the transmittance of the TM wave to the TE wave (T TM / T TE ), the height H of the metal line 721 has an impact on the extinction ratio, and the larger the H value, the higher the extinction ratio. Figures 11B-11E As shown in FIG, the influence of various parameters in the metal wire grid polarizer 7 on the performance of the light emitting element is analyzed and explained. Figure 11B As shown in , in the visible light band, the extinction ratio increases as the period d decreases; Figure 11C As shown in Figure 2, as the duty cycle a / d increases, the transmittance of the TM wave decreases, while the extinction ratio increases. Therefore, for a fixed wire grid period d, the duty cycle needs to be determined according to the requirements. Figure 11D As shown in FIG. 1 , as the height H (groove depth) of the metal line 721 increases, the TM transmittance first decreases and then increases, with an overall downward trend, while the TE wave transmittance decreases sharply, so the extinction ratio increases sharply; as shown in FIG. Figure 11E As shown, Figure 11E The wire grid period d of the metal wire grid, the height H of the metal wire 721 and the polarization degree PE of the metal wire grid polarizer 7 ((T TM -T TE ) / (T TM +T TE )) It can be seen that PE increases with the decrease of wire grid period d, and PE increases with the increase of height H of metal wire 721. In order to ensure that the metal wire grid polarizer 7 can maximize the light utilization rate, the total transmittance T (T TM +T TE ) and polarization degree PE. Based on the above trend analysis, when the WGP wire grid period d ≤ 120nm and the height H of the metal wire 721 ≥ 140nm, higher total transmittance T and polarization degree PE can be achieved. For example, when d = 120nm and PE = 99.94% to 99.96%, T = 36% to 40%. To further improve transmittance, it is necessary to reduce the WGP duty cycle a / d, such as Figure 12 As shown in FIG, when a / d=55 / 121nm, PE=99.94%, T=36~40%. Therefore, in the specific implementation, in the above-mentioned light-emitting element provided by the embodiment of the present invention, as Figure 11A As shown, the wire grid period d of the metal wire grid polarizer 7 is less than or equal to 120 nm, the height of the metal wire 721 is greater than or equal to 140 nm, and the duty cycle of the metal wire grid polarizer 7 is 0.35-0.5.

[0096] Specifically, the material of the metal wire 721 of the metal wire grid polarizer 7 can be Al, Ag, Au, Cu, or Gr. Preferably, the material of the metal wire 721 is Al. When Al is selected to make the metal wire grid, the TM transmittance and extinction ratio are high.

[0097] Below is Figure 1 As an example, the specific structure of the light emitting unit 2 provided in the embodiment of the present invention is described. Figure 13 As shown, Figure 13 A structural schematic diagram of a metal reflective structure 3, a connecting layer 6 and a light-emitting unit 2 is provided on a sapphire substrate 100. The light-emitting unit 2 includes: a quantum well layer 201, a P-type semiconductor layer 202, a P-electrode 203 (e.g., ITO), an N-electrode 204 (e.g., a metal material), a P-type pad 205 and an N-type pad 206. The P-type pad 205 is electrically connected to the P-electrode 203 through a via penetrating the insulating layer 207, and the N-type pad 206 is electrically connected to the N-electrode 204 through a via penetrating the insulating layer 207.

[0098] Below is Figure 1 Taking the light-emitting element shown in FIG. 1 as an example, the method for manufacturing the light-emitting element provided by the embodiment of the present invention is described in detail:

[0099] (1) A light shielding layer 12 and a color filter layer 13 (R-CF, B-CF, G-CF) are formed on a glass substrate 71'. Figure 14A As shown;

[0100] (2) In Figure 14A A retaining wall structure 4 is formed on the basis of the retaining wall structure, which has a plurality of sub-pixel openings (41, 42, 43). Figure 14B As shown;

[0101] (3) In Figure 14B Each sub-pixel opening (41, 42, 43) forms a quantum dot color conversion film 5 (R-QD, G-QD) and a resin material 11, such as Figure 14C shown.

[0102] (4) In Figure 14C The quantum dot encapsulation layer 10 is formed on the basis of Figure 14D As shown;

[0103] (5) A metal reflective structure 3 and a connecting layer 6 are formed on the sapphire substrate 100, as shown in FIG. Figure 14E As shown; the metal reflective structure 3 can be formed by a step exposure process, and GaN is coated once after each step exposure process to form a connecting layer 6;

[0104] (6) In Figure 14E The light emitting unit 2 is formed on the basis of Figure 14FAs shown; the specific structure of the light emitting unit 2 is as shown Figure 13 As shown;

[0105] (7) In Figure 14F An adhesive layer 200, a debonding layer 300 and a temporary carrier 400 are sequentially formed on the side of the light emitting unit 2 facing away from the sapphire substrate 100. Figure 14G As shown;

[0106] (8) Figure 14G The sapphire substrate 100 is peeled off, as shown in FIG14H;

[0107] (9) In Figure 14H A metal bonding layer 8 and a flat layer 9 are formed on the basis of Figure 14I shown.

[0108] (10) Figure 14D and Figure 14I The structure shown is bound to the bit, such as Figure 14J As shown;

[0109] (11) Figure 14K As shown, remove Figure 14J The adhesive layer 200, the debonding layer 300 and the temporary carrier 400, as Figure 14L As shown;

[0110] (12) Thinning with HF acid Figure 14L The glass substrate 71' is formed into a cover plate 71, and a metal wire grid 72 is formed on the cover plate 71. Figure 14M As shown;

[0111] (13) Figure 14M The light emitting unit 2 is bound to the substrate 1 (driving backplane), such as Figure 1 shown.

[0112] In summary, the above steps (1) to (13) can be used to prepare the Figure 1 The light-emitting element shown.

[0113] Based on the same inventive concept, an embodiment of the present invention further provides a display device, comprising any of the above-mentioned light-emitting elements provided in an embodiment of the present invention. The display device can be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, a navigator, etc. Other essential components of the display device are well understood by those skilled in the art and will not be described in detail here, nor should they be construed as limitations of the present invention. The implementation of the display device can refer to the embodiments of the above-mentioned light-emitting elements, and repeated parts will not be described in detail.

[0114] In a specific implementation, when the display device provided by the embodiment of the present invention is an OLED display device, the above-mentioned light-emitting element provided by the embodiment of the present invention can be used as a pixel unit of the OLED display device to emit light.

[0115] In a specific implementation, when the display device provided by the embodiment of the present invention is an LCD display device, the above-mentioned light-emitting element provided by the embodiment of the present invention can be used as a backlight source of the LCD display device, such as Figure 15 As shown, Figure 15 : This is a structural schematic diagram of an LCD display device, including a liquid crystal display panel and the above-mentioned light-emitting element provided by an embodiment of the present invention, located on the light-incident side of the liquid crystal display panel. The liquid crystal display panel includes: an array substrate 110 and a color filter substrate 120 arranged opposite to each other, a liquid crystal layer (not shown) located between the array substrate 110 and the color filter substrate 120, a first polarizer 130 located on the side of the array substrate 110 facing away from the color filter substrate 120, and a second polarizer 140 located on the side of the color filter substrate 120 facing away from the array substrate 110; the light-emitting element 150 provided by an embodiment of the present invention is located on the side of the first polarizer 130 facing away from the second polarizer 140. The display device also includes a diffusion film 160 located between the first polarizer 130 and the light-emitting element 150, and a backlight encapsulation layer 170 located between the diffusion film 160 and the light-emitting element 150; wherein the optical distance OD between the diffusion film 160 and the backlight encapsulation layer 170 is 0.2-0.5 mm.

[0116] Specifically, the light emitting element 150 is assembled with the LCD display panel through the optical distance OD and the diffusion film 160. The optical distance OD provides a uniform light path to achieve uniformity requirements, which can also be achieved through the diffusion film 160 (or the optical distance + diffusion film are achieved together).

[0117] The display device provided in the embodiment of the present invention can be a head-mounted display such as AR / VR, which has very high requirements for pixel resolution. The light-emitting elements provided in the embodiment of the present invention and the pixel units in the LCD display panel can have a one-to-many correspondence relationship, for example Figure 8 One repeating light-emitting unit in the display panel can correspond to nine pixel units (R, G, B).

[0118] An embodiment of the present invention provides a light-emitting element and a display device. A metal reflective structure is provided between a retaining wall structure and a light-emitting unit. Since the side wall (reflective surface) of the first hollow structure of the metal reflective structure is inclined relative to the light-emitting surface of the light-emitting unit, when the divergent light emitted by the light-emitting unit is incident on the side wall (reflective surface) of the first hollow structure, the side wall (reflective surface) of the first hollow structure can cause more light to be directed toward the quantum point color conversion film, thereby greatly improving the utilization rate of light and obtaining a light-emitting element with high light efficiency.

[0119] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A light-emitting element, characterized in that: include: substrate; A plurality of light-emitting units are located on the base substrate; a metal reflective structure, located on a side of the light-emitting unit facing away from the base substrate; The metal reflective structure has a plurality of first hollow structures, the orthographic projection of the light-emitting unit on the base substrate is located within the orthographic projection range of the first hollow structure on the base substrate, and the sidewalls of the first hollow structure are arranged obliquely relative to the light-emitting surface of the light-emitting unit; a retaining wall structure, located on a side of the metal reflective structure facing away from the base substrate; The retaining wall structure has a plurality of sub-pixel openings, the first hollow structures correspond to the sub-pixel openings one-to-one, and the orthographic projection of the first hollow structure on the base substrate is located within the orthographic projection range of the sub-pixel openings on the base substrate; a plurality of quantum dot color conversion films, wherein the quantum dot color conversion films are disposed in at least a portion of the sub-pixel openings; a connecting layer, located between the metal reflective structure and the retaining wall structure, the connecting layer filling the first hollow structure; a metal bonding layer, located between the connecting layer and the retaining wall structure; The metal bonding layer has a plurality of second hollow structures and metal bonding portions located between adjacent second hollow structures, and the first hollow structures and the second hollow structures are arranged opposite to each other.

2. The light-emitting element according to claim 1, wherein The metal reflective structure includes a plurality of reflective parts independently arranged around each of the light-emitting units, the reflective parts have the first hollow structure, and the connecting layer further fills the gaps between adjacent reflective parts.

3. The light-emitting element according to claim 2, wherein The reflective portion includes a body and a reflective layer located between the body and the connecting layer. The material of the body includes resin, and the material of the reflective layer includes ITO / Ag / ITO.

4. The light-emitting element according to claim 3, wherein The cross-section of the body along the thickness direction of the base substrate is a triangle, and the inner angle of the triangle pointing to the light-emitting unit is an acute angle.

5. The light-emitting element according to claim 4, wherein The sum of the inner angle and the light-emitting angle of the light-emitting unit is less than 90°.

6. The light-emitting element according to any one of claims 1 to 5, wherein: It also includes a metal wire grid polarizer located on the side of the multiple quantum dot color conversion films away from the base substrate. The metal wire grid polarizer includes a cover plate and a metal wire grid located on the side of the cover plate away from the base substrate. The metal wire grid includes a plurality of metal wires arranged in parallel and spaced apart.

7. The light-emitting element according to claim 6, wherein The period of the metal wire grid is less than or equal to 120 nm, the height of the metal wire is greater than or equal to 140 nm, and the duty cycle of the metal wire grid is 0.35-0.

5.

8. The light-emitting element according to any one of claims 1 to 5, wherein: The orthographic projection of the metal bonding portion on the base substrate coincides with the orthographic projection of the retaining wall structure on the base substrate.

9. The light-emitting element according to claim 8, wherein The metal bonding portion includes a first Cu layer, an In layer, and a second Cu layer that are stacked.

10. The light-emitting element according to claim 9, wherein The first Cu layer and the second Cu layer have the same thickness, and a ratio of the thickness of the first Cu layer to the thickness of the In layer is greater than 1.2:

1.

11. The light-emitting element according to claim 8, wherein The invention also includes a flat layer filling the second hollow structure.

12. The light-emitting element according to claim 11, wherein It also includes a quantum dot encapsulation layer located between the metal bonding layer and the retaining wall structure, and the quantum dot encapsulation layer covers the base substrate in an orthographic projection on the base substrate.

13. The light-emitting element according to any one of claims 1 to 5, wherein: The retaining wall structure is made of reflective material.

14. The light-emitting element according to any one of claims 1 to 5, wherein: The luminous color of the light-emitting unit is blue, and the sub-pixel openings include a first sub-pixel opening, a second sub-pixel opening, and a third sub-pixel opening. The red quantum dot color conversion film is set in the first sub-pixel opening, the green quantum dot color conversion film is set in the second sub-pixel opening, and the third sub-pixel opening is filled with resin material, and the resin material contains scattering particles.

15. The light-emitting element according to claim 6, wherein It also includes a light-shielding layer and a color filter layer located between the retaining wall structure and the cover plate, the light-shielding layer has a plurality of through holes corresponding one-to-one to the sub-pixel openings, and the color filter layer includes a plurality of color resists, which correspond one-to-one to the quantum dot color conversion film and are respectively located in each of the through holes.

16. The light-emitting element according to any one of claims 1 to 5, wherein: The light-emitting unit includes Mini LED or Micro LED.

17. A display device, characterized in that: The light-emitting element comprises the light-emitting element according to any one of claims 1 to 16.

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