Light-emitting device, backlight module and display device

Abstract

A light emitting device includes: a metal wire grid; the first semiconductor layer is positioned on one side of the metal wire grid; the light-emitting layer is positioned on one side, far away from the metal wire grid, of the first semiconductor layer; the second semiconductor layer is positioned on one side, far away from the metal wire grid, of the light-emitting layer; a plurality of grooves are formed in the surface of one side, far away from the first semiconductor layer, of the second semiconductor layer; and the phase conversion layer covers the second semiconductor layer, and a part of the phase conversion layer is located in the plurality of grooves.

Description

Light-emitting device, backlight module and display device Technical Field

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

[0002] A wire grid polarizer (WGP) is a wire grid polarizer with excellent polarization performance, high transmittance, and flexible design. It can also be used as a polarization beam splitter.

[0003] The metal wire grid can be used in a light emitting device so that the light emitting device emits light in a single polarization state.

[0004] Summary of the Invention

[0005] On the one hand, a light-emitting device is provided, comprising a first light conversion layer, an epitaxial structure and at least one metal wire grid. The epitaxial structure is located on the first light conversion layer, and the epitaxial structure is used to emit light. The at least one metal wire grid is located on the epitaxial structure. Wherein, the first light conversion layer is configured to change the direction of travel of part of the light incident on the first light conversion layer, so that the light after the direction of travel is changed is emitted in a direction toward the metal wire grid, and the polarization direction of at least part of the light after the direction of travel is changed is changed; the polarization direction of at least part of the light emitted from the first light conversion layer is changed. In some embodiments, the first light conversion layer includes: a phase conversion layer. The phase conversion layer includes: a plurality of nanocolumn structures. The plurality of nanocolumn structures are arranged in an array.

[0006] In some embodiments, the light-emitting device further includes: a first reflective layer covering the top surface and side surfaces of each nanorod structure.

[0007] In some embodiments, the first light conversion layer includes a mirror reflection layer configured to reflect a portion of the light incident on the mirror reflection layer; and the reflectivity of the mirror reflection layer is greater than or equal to 80%.

[0008] In some embodiments, the first light conversion layer includes a scattering reflective layer. The scattering reflective layer is configured to scatter or reflect a portion of the light incident on the scattering reflective layer, and convert at least a portion of the light scattered or reflected by the scattering reflective layer into natural light; the roughness of the scattering reflective layer is greater than or equal to 2μm.

[0009] In some embodiments, the light-emitting device further comprises: a second light conversion layer located between the epitaxial structure and the at least one metal wire grid, wherein the second light conversion layer is configured to reflect or transmit a portion of the light incident on the second light conversion layer, and to change the polarization direction of at least a portion of the light emitted after passing through the second light conversion layer.

[0010] In some embodiments, the second light conversion layer is further configured to change the color of a portion of the light incident on the second light conversion layer.

[0011] In some embodiments, the metal wire grid includes: a first metal layer, a light-transmitting dielectric layer, and a second metal layer. The first metal layer includes a plurality of first metal patterns. The plurality of first metal patterns extend along a first direction and are arranged at intervals along a second direction. The first direction intersects with the second direction. The light-transmitting dielectric layer includes a plurality of light-transmitting dielectric patterns, each of which extends along the first direction, and the plurality of light-transmitting dielectric patterns are arranged at intervals along the second direction. The light-transmitting dielectric pattern is located between two adjacent first metal patterns. The second metal layer includes a plurality of second metal patterns. Each second metal pattern extends along the first direction, and the plurality of second metal patterns are arranged at intervals along the second direction. One second metal pattern is located on one of the light-transmitting dielectric patterns.

[0012] In some embodiments, along a direction perpendicular to the plane where the metal wire grid is located and along the second direction, a cross-sectional shape of the light-transmitting medium pattern includes an inverted trapezoid.

[0013] In some embodiments, a size of the first metal pattern along the second direction is equal to a size of the second metal pattern along the second direction.

[0014] In some embodiments, a thickness of the first metal pattern is substantially equal to a thickness of the second metal pattern.

[0015] In some embodiments, the thickness of the first metal pattern is in a range of 20 nm to 80 nm, and / or the thickness of the second metal pattern is in a range of 20 nm to 80 nm.

[0016] In some embodiments, the refractive index of the light-transmitting medium pattern ranges from 1.4 to 1.5.

[0017] In some embodiments, when the light-emitting device emits blue light, the repetition period of the second metal pattern in the second direction is less than or equal to 140 nm. Furthermore, the thickness of the light-transmitting medium pattern ranges from 60 nm to 80 nm. Furthermore, the size of the light-transmitting medium pattern in the second direction ranges from 50 nm to 70 nm.

[0018] In some embodiments, when the light-emitting device emits green or red light, the repetition period of the second metal pattern in the second direction is less than or equal to 240 nm. Furthermore, the thickness of the light-transmitting medium pattern ranges from 70 nm to 90 nm. Furthermore, the size of the light-transmitting medium pattern in the second direction ranges from 110 nm to 130 nm.

[0019] In some embodiments, the light emitting device further comprises: a buffer layer located between the epitaxial structure and the at least one metal wire grid.

[0020] In some embodiments, the buffer layer has a thickness ranging from 60 nm to 80 nm.

[0021] In some embodiments, the refractive index of the buffer layer is in the range of 1.4 to 1.5.

[0022] In some embodiments, the light-emitting device further includes a second reflective layer. The second reflective layer surrounds at least the first light conversion layer and side surfaces of the epitaxial structure, and is configured to reflect light incident on the second reflective layer and emit the reflected light toward a light-emitting side of the light-emitting device.

[0023] On the other hand, a backlight module is provided, comprising: a substrate, and a plurality of light-emitting devices as described in any one of the above embodiments and located on the substrate.

[0024] In some embodiments, the backlight module further includes: at least one light-uniform layer located on the plurality of light-emitting devices.

[0025] In some embodiments, the light-homogenizing layer includes: prisms and multiple micro-transparent structures. The multiple micro-transparent structures are located on the body. Each micro-transparent structure extends along a first direction, and the multiple micro-transparent structures are arranged along a second direction. The micro-transparent structures are configured to homogenize and / or collimate the light emitted by the light-emitting device.

[0026] In some embodiments, a surface of the micro-transmitting structure close to the plurality of light-emitting devices is an arched surface.

[0027] In some embodiments, a ratio of the arch height to the arch diameter is less than or equal to 1.5.

[0028] In some embodiments, the backlight module further comprises a first barrier layer and an encapsulation layer. The first barrier layer is located on the substrate, between two adjacent light-emitting devices, and in contact with the side surfaces of the light-emitting devices. The first barrier layer is configured to absorb light incident on the first barrier layer through the side surfaces of the light-emitting devices. The encapsulation layer covers the multiple light-emitting devices and the first barrier layer.

[0029] In some embodiments, the backlight module further comprises an encapsulation layer and a second barrier layer. The encapsulation layer is located on the substrate and covers the plurality of light-emitting devices. The second barrier layer is located on a side of the encapsulation layer away from the plurality of light-emitting devices. The second barrier layer includes multiple openings, with one opening directly opposite a light-emitting device. The second barrier layer is configured to absorb or reflect light incident on the second barrier layer from the light-emitting device.

[0030] On the other hand, a display device is provided, comprising: a plurality of light-emitting devices as described in any one of the above embodiments, or a backlight module as described in any one of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] To more clearly illustrate the technical solutions of the present disclosure, the following briefly introduces the drawings required for use in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure, and those skilled in the art can also derive other drawings based on these drawings. Furthermore, the drawings described below should be considered schematic diagrams and are not intended to limit the actual dimensions, etc., of the products involved in the embodiments of the present disclosure.

[0032] FIG1 is a schematic diagram of a display device according to some embodiments of the present disclosure;

[0033] FIG2 is a structural diagram of a display panel according to some embodiments of the present disclosure;

[0034] FIG3 is a structural diagram of another display device according to some embodiments of the present disclosure;

[0035] FIG4 is a structural diagram of a backlight module according to some embodiments of the present disclosure;

[0036] FIG5 is a structural diagram of another backlight module according to some embodiments of the present disclosure;

[0037] FIG6A is a structural diagram of a substrate and a light-emitting device according to some embodiments of the present disclosure;

[0038] FIG6B is a structural diagram of another substrate and a light-emitting device according to some embodiments of the present disclosure;

[0039] FIG6C is a structural diagram of another substrate and a light-emitting device according to some embodiments of the present disclosure;

[0040] FIG6D is a structural diagram of a driving circuit and a light-emitting device according to some embodiments of the present disclosure;

[0041] FIG7 is a diagram comparing characteristics of four display devices in the related art;

[0042] FIG8 is a structural diagram of a display device improved according to the related art;

[0043] FIG9 is a structural diagram of a light emitting device according to some embodiments of the present disclosure;

[0044] FIG10 is a structural diagram of another light emitting device according to some embodiments of the present disclosure;

[0045] FIG11 is a structural diagram of another light emitting device according to some embodiments of the present disclosure;

[0046] FIG12 is a structural diagram of a metal wire grid of a dual wire grid structure according to some embodiments of the present disclosure;

[0047] 13 and 14 are graphs showing the relationship between transmittance, absorptivity, reflectivity and wavelength of a metal wire grid of a dual wire grid structure according to some embodiments of the present disclosure;

[0048] FIG15 is a structural diagram of a metal wire grid of a single wire grid structure according to some embodiments of the present disclosure;

[0049] 16 and 17 are diagrams showing the relationship between transmittance and polarization degree of a metal wire grid with a single wire grid structure and a metal wire grid with a double wire grid structure according to some embodiments of the present disclosure;

[0050] FIG18 is a structural diagram of another light emitting device according to some embodiments of the present disclosure;

[0051] FIG19 is a graph showing the relationship between transmittance, absorptivity, polarization degree and wavelength of the light emitting device shown in FIG18;

[0052] FIG20 is a structural diagram of another light emitting device according to some embodiments of the present disclosure;

[0053] FIG21 is a diagram showing the relationship between transmittance, absorptivity, polarization degree and wavelength of the light emitting device shown in FIG20 ;

[0054] FIG22 is a structural diagram of another light emitting device according to some embodiments of the present disclosure;

[0055] 23 and 24 are diagrams showing the relationship between transmittance, polarization degree and wavelength according to the light emitting device shown in FIG. 22 ;

[0056] FIG25 is a structural diagram of a metal wire grid according to some embodiments of the present disclosure;

[0057] FIG26 is a structural diagram of another metal wire grid according to some embodiments of the present disclosure;

[0058] FIG27 is a graph showing the relationship between transmittance and wavelength of four metal wire grids according to some embodiments of the present disclosure;

[0059] FIG28 is a graph showing the relationship between the polarization degree and wavelength of four metal wire grids according to some embodiments of the present disclosure;

[0060] FIG29 is a graph showing the relationship between transmittance and wavelength of metal wire grids made of three different metal materials according to some embodiments of the present disclosure;

[0061] FIG30 is a graph showing the relationship between the absorptivity and wavelength of metal wire grids made of three different metal materials according to some embodiments of the present disclosure;

[0062] FIG31 is a graph showing the relationship between the reflectivity and wavelength of metal wire grids made of three different metal materials according to some embodiments of the present disclosure;

[0063] FIG32 is a graph showing the relationship between transmittance and wavelength of metal wire grids formed with three different second metal layer thicknesses according to some embodiments of the present disclosure;

[0064] FIG33 is a graph showing the relationship between the absorptivity and wavelength of a metal wire grid composed of three different second metal layer thicknesses according to some embodiments of the present disclosure;

[0065] FIG34 is a graph showing the relationship between the reflectivity and wavelength of a metal wire grid composed of three different second metal layer thicknesses according to some embodiments of the present disclosure;

[0066] FIG35 is a graph showing the relationship between transmittance, absorptivity, and reflectivity and wavelength of a metal wire grid formed with three different second metal layer thicknesses according to some embodiments of the present disclosure;

[0067] FIG36 is a graph showing the relationship between the transmittance and wavelength of a metal wire grid formed of various light-transmitting medium patterns with different refractive indices according to some embodiments of the present disclosure;

[0068] FIG37 is a graph showing the relationship between the absorptivity and wavelength of a metal wire grid formed of various light-transmitting medium patterns with different refractive indices according to some embodiments of the present disclosure;

[0069] FIG38 is a graph showing the relationship between the reflectivity and wavelength of a metal wire grid formed of various light-transmitting medium patterns with different refractive indices according to some embodiments of the present disclosure;

[0070] FIG39 is a graph showing the relationship between transmittance, absorptivity, and reflectivity and wavelength of a metal wire grid formed of various light-transmitting medium patterns with different refractive indices according to some embodiments of the present disclosure;

[0071] FIG40 is a graph showing the relationship between transmittance and wavelength of a metal wire grid formed by various repeating periods of the second metal pattern according to some embodiments of the present disclosure;

[0072] FIG41 is a graph showing the relationship between the absorptivity and wavelength of a metal wire grid formed by various repeating periods of the second metal pattern according to some embodiments of the present disclosure;

[0073] FIG42 is a graph showing the relationship between the reflectivity and wavelength of a metal wire grid formed by various repeating periods of the second metal pattern according to some embodiments of the present disclosure;

[0074] FIG43 is a graph showing the relationship between transmittance, absorptivity and wavelength of a metal wire grid formed by various repeating periods of the second metal pattern according to some embodiments of the present disclosure;

[0075] FIG44 is a graph showing the relationship between transmittance and wavelength of metal wire grids with various line widths according to some embodiments of the present disclosure;

[0076] FIG45 is a graph showing the relationship between the absorptivity and wavelength of metal wire grids of various line widths according to some embodiments of the present disclosure;

[0077] FIG46 is a graph showing the relationship between the reflectivity and wavelength of metal wire grids of various line widths according to some embodiments of the present disclosure;

[0078] FIG47 is a graph showing the relationship between transmittance, absorptivity and wavelength of metal wire grids with various line widths according to some embodiments of the present disclosure;

[0079] FIG48 is a graph showing the relationship between the transmittance and wavelength of a metal wire grid formed by various thicknesses of light-transmitting medium patterns according to some embodiments of the present disclosure;

[0080] FIG49 is a graph showing the relationship between the absorptivity and wavelength of a metal wire grid formed by various thicknesses of light-transmitting medium patterns according to some embodiments of the present disclosure;

[0081] FIG50 is a graph showing the relationship between the reflectivity and wavelength of a metal wire grid formed by various thicknesses of light-transmitting medium patterns according to some embodiments of the present disclosure;

[0082] FIG51 is a graph showing the relationship between transmittance, absorptivity and wavelength of a metal wire grid formed by various thicknesses of light-transmitting medium patterns according to some embodiments of the present disclosure;

[0083] FIG52 is a graph showing the relationship between transmittance, absorptivity and wavelength for a light emitting device with a buffer layer and a light emitting device without a buffer layer according to some embodiments of the present disclosure;

[0084] FIG53 is a graph showing the relationship between transmittance and wavelength of a metal wire grid formed with various buffer layer thicknesses according to some embodiments of the present disclosure;

[0085] FIG54 is a graph showing the relationship between the wire grid rate and wavelength of a metal wire grid formed with various buffer layer thicknesses according to some embodiments of the present disclosure;

[0086] FIG55 is a graph showing the relationship between the reflectivity and wavelength of a metal wire grid formed with various buffer layer thicknesses according to some embodiments of the present disclosure;

[0087] FIG56 is a graph showing the relationship between transmittance, absorptivity and wavelength of a metal wire grid formed with various buffer layer thicknesses according to some embodiments of the present disclosure;

[0088] FIG57 is a graph showing the relationship between transmittance and wavelength of a metal wire grid composed of various buffer layers with different refractive indices according to some embodiments of the present disclosure;

[0089] FIG58 is a graph showing the relationship between the wire grid ratio and wavelength of a metal wire grid composed of various buffer layer refractive indices according to some embodiments of the present disclosure;

[0090] FIG59 is a graph showing the relationship between the reflectivity and wavelength of a metal wire grid composed of various buffer layers with different refractive indices according to some embodiments of the present disclosure;

[0091] FIG60 is a graph showing the relationship between transmittance, absorptivity and wavelength of a metal wire grid formed with various refractive indices of buffer layers according to some embodiments of the present disclosure;

[0092] FIG61 is a graph showing the relationship between transmittance, polarization degree, and wavelength when the metal wire grid includes a substrate according to some embodiments of the present disclosure;

[0093] FIG62 is a graph showing the relationship between transmittance, polarization degree, and wavelength of an optimized metal wire grid according to some embodiments of the present disclosure;

[0094] FIG63 is a graph showing the relationship between the absorptivity, reflectivity, and transmittance of an optimized metal wire grid and wavelength according to some embodiments of the present disclosure;

[0095] FIG64 is a structural diagram of a phase conversion layer according to some embodiments of the present disclosure;

[0096] FIG65 is a structural diagram of another phase conversion layer according to some embodiments of the present disclosure;

[0097] FIG66 is a structural diagram of yet another phase conversion layer according to some embodiments of the present disclosure;

[0098] FIG67 is a structural diagram of yet another light emitting device according to some embodiments of the present disclosure;

[0099] FIG68 is a diagram showing light emission distribution of a single light emitting device according to some embodiments of the present disclosure;

[0100] FIG69 is a diagram showing light emission distribution of a plurality of light emitting devices arranged in an array according to some embodiments of the present disclosure;

[0101] FIG70 is a diagram comparing light emission between a single light emitting device and a plurality of light emitting devices arranged in an array according to some embodiments of the present disclosure;

[0102] FIG71 is a structural diagram of a backlight module in one implementation;

[0103] FIG72 is a schematic diagram of testing deflection according to some embodiments of the present disclosure;

[0104] FIG73 is a comparison diagram of the deflection coefficient and transmittance of each optical film layer in a backlight module in one implementation;

[0105] FIG74 is a structural diagram of yet another backlight module according to some embodiments of the present disclosure;

[0106] FIG75 is a diagram showing the relationship between optical distance and uniformity in a backlight module according to some embodiments of the present disclosure;

[0107] FIG76 is a diagram showing the relationship between the number of dodging layers and uniformity in a backlight module according to some embodiments of the present disclosure;

[0108] FIG77 is a diagram showing the relationship between the displacement offset and uniformity of a dodging layer in a backlight module according to some embodiments of the present disclosure;

[0109] FIG78 is a graph showing the number, uniformity, and de-skewness of light-dotting layers in a backlight module according to some embodiments of the present disclosure;

[0110] FIG79 is a structural diagram of a light-dotting layer and a substrate according to some embodiments of the present disclosure;

[0111] FIG80 is a diagram showing the relationship between the dome height and the deflection resolution of a dodging layer according to some embodiments of the present disclosure;

[0112] FIG81 is a diagram showing the relationship between the aperture and uniformity of a dodging layer according to some embodiments of the present disclosure;

[0113] 82 and 83 are diagrams showing the relationship between the focusing capability and focusing angle of the light-dotting layer at various heights according to some embodiments of the present disclosure;

[0114] FIG84 is a diagram showing the relationship between the gain coefficient and aperture of a dodging layer according to some embodiments of the present disclosure;

[0115] FIG85 is a graph showing the relationship between the gain coefficient and the dome height of a dodging layer according to some embodiments of the present disclosure;

[0116] FIG86 is a structural diagram of yet another backlight module according to some embodiments of the present disclosure;

[0117] FIG87 is a structural diagram of yet another backlight module according to some embodiments of the present disclosure;

[0118] 88 to 95 are flowcharts of a preparation process of a light-emitting device according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0119] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the embodiments described are only some embodiments of the present disclosure, rather than all embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present disclosure.

[0120] Unless the context requires otherwise, throughout the specification and claims, the term "comprise" and its other forms, such as the third person singular form "comprises" and the present participle form "comprising", are to be interpreted as open and inclusive, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" are intended to indicate that the particular features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the particular features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0121] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.

[0122] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0123] The use of "adapted to" or "configured to" herein is intended to be open and inclusive language that does not exclude devices adapted or configured to perform additional tasks or steps.

[0124] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of deviation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0125] As used herein, "perpendicular" and "equal" include the conditions described and conditions similar to the conditions described, where the range of the similar conditions is within an acceptable deviation range, where the acceptable deviation range is determined by a person of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system). For example, "perpendicular" includes absolute perpendicularity and approximate perpendicularity, where the acceptable deviation range for approximate perpendicularity can also be, for example, a deviation within 5°. "Equal" includes absolute equality and approximate equality, where the acceptable deviation range for approximate equality can be, for example, that the difference between the two equalities is less than or equal to 5% of either.

[0126] It will be understood that when a layer or element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present therebetween.

[0127] Exemplary embodiments are described herein with reference to cross-sectional and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are contemplated. Therefore, the exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include deviations in shape due to, for example, manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device and are not intended to limit the scope of the exemplary embodiments.

[0128] As shown in FIG1 , some embodiments of the present disclosure provide a display device 1. The display device 1 can be any display device that displays either motion (e.g., video) or fixed (e.g., still images) and whether text or images. More specifically, it is expected that the display device of the embodiments described can be implemented in or associated with a variety of electronic devices, such as (but not limited to) mobile phones, wireless devices, personal data assistants (PDAs), handheld or portable computers, GPS receivers / navigators, cameras, MP4 video players, video cameras, game consoles, watches, clocks, calculators, television monitors, flat-panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigation systems, cockpit controls and / or displays, camera view displays (e.g., displays of rearview cameras in vehicles), electronic photos, electronic billboards or signs, projectors, architectural structures, packaging, and aesthetic structures (e.g., displays of images of jewelry), etc.

[0129] Exemplarily, the display device 1 can be used in near-eye display fields such as 2D, 3D, VR (Virtual Reality), AR (Augmented Reality), MR (Mixed Reality), and lighting fields.

[0130] Illustratively, the display device 1 includes: a frame, a display driver IC (Integrated Circuit), and other electronic components.

[0131] In some embodiments, the display device 1 further includes a light-emitting substrate. The light-emitting substrate can be used directly for displaying images. In this case, the display device 1 is an active light-emitting display device. Since the light-emitting substrate can emit light on its own, there is no need for a separate backlight module.

[0132] Exemplarily, the light emitting substrate 30 includes a light emitting device, such as an LED (Light Emitting Diode).

[0133] In some other embodiments, the display device 1 further includes a display panel 10 .

[0134] In some examples, the display panel 10 may be an LCD (Liquid Crystal Display) display panel.

[0135] Exemplarily, the display panel 10 may be driven by a passive matrix (PM) driving mode or an active matrix (AM) driving mode. When the display panel 10 is driven by an active matrix driving mode, the display panel 10 may be, for example, a thin film transistor liquid crystal display (TFT-LCD) panel.

[0136] For example, as shown in FIG. 2 , the display panel 10 may include an array substrate 11 , a liquid crystal layer 12 , and a color filter substrate 13 , which are stacked in sequence.

[0137] For example, the array substrate 11 may include: a plurality of pixel electrodes 111 and a plurality of pixel driving circuits 112 . The plurality of pixel electrodes 111 are electrically connected to the plurality of pixel driving circuits 112 in a one-to-one correspondence, and the pixel driving circuits 112 provide pixel voltages to the corresponding pixel electrodes 111 .

[0138] Exemplarily, the display panel 10 further includes a common electrode.

[0139] The setting position of the common electrode is related to the display type of the display panel 10. In the embodiment of the present disclosure, the display type of the display panel 10 can be ADS (Advanced Super Dimension Switch) display type, IPS (In-Plane Switching) display type, VA (Vertical Alignment) display type, FFS (Fringe Field Switching) display type, TN (Twisted Nematic) display type, etc. Therefore, there are multiple setting positions of the common electrode in the embodiment of the present disclosure.

[0140] For example, when the display panel 10 is an IPS display type, the common electrode can be set on the array substrate 11 and set on the same layer as the pixel electrode 111. Thus, the common electrode and the pixel electrode 111 can be formed simultaneously in one composition process, thereby simplifying the preparation process of the display panel 10.

[0141] For another example, when the display panel 10 is of the FFS display type or the ADS display type, the common electrode can be provided on the array substrate 11 and located on a different layer from the pixel electrode 111. This can prevent interference between the pixel voltage signal on the pixel electrode 111 and the common voltage on the common electrode, thereby improving the signal accuracy of the pixel voltage signal and the common voltage.

[0142] For another example, when the display panel 10 is of a TN display type or a VA display type, the common electrode may be provided on the color filter substrate 13 .

[0143] For example, the liquid crystal layer 12 includes a plurality of liquid crystal molecules. For example, if the display panel 10 is a TN display type, an electric field may be formed between the pixel electrode 111 and the common electrode, and the liquid crystal molecules between the pixel electrode 110 and the common electrode may be deflected under the action of the electric field.

[0144] Exemplarily, the color filter substrate 13 includes multiple color filters. For example, when the light incident on the color filter is white light, the color filters may include a red filter, a green filter, and a blue filter. For example, the red filter can only transmit red light from the incident light, the green filter can only transmit green light from the incident light, and the blue filter can only transmit blue light from the incident light. For another example, when the light incident on the color filter is blue light, the color filters may include a red filter and a green filter.

[0145] Of course, the color filter substrate 13 also includes a black matrix, which can be used to prevent light mixing.

[0146] Exemplarily, as shown in FIG3 , the display device 1 further includes a backlight module 20 .

[0147] Exemplarily, the backlight module 20 is used to provide backlight for the display panel 10. The display panel 10 is located on the light-emitting side of the backlight module 20. The light-emitting side of the backlight module 20 refers to the side from which the backlight module 20 emits light.

[0148] It is understood that the backlight provided by the backlight module 20 can pass through the array substrate 11 and be incident on the liquid crystal molecules in the liquid crystal layer 12. Under the influence of the electric field formed between the pixel electrode 111 and the common electrode, the liquid crystal molecules undergo a certain degree of flipping, thereby changing the polarization direction of the light passing through the liquid crystal molecules. This light passes through the different color filters in the color filter substrate 13 and then exits. This exiting light includes light of various colors, such as red, green, and blue. The various colors of light interact with each other to enable the display device 1 to achieve display.

[0149] Exemplarily, the backlight module 20 may be a direct-lit backlight module or an edge-lit backlight module. FIG. 4 shows an edge-lit backlight module, and FIG. 5 shows a direct-lit backlight module.

[0150] As shown in Figures 4 and 5, edge-lit backlight modules are generally thinner and lighter than direct-lit backlight modules. However, direct-lit backlight modules can independently control the brightness of different areas, thereby providing localized backlighting and ultra-high contrast backlighting.

[0151] The backlight module 20 is taken as an example to introduce the backlight module.

[0152] In some embodiments, as shown in FIG. 6A to FIG. 6C , the backlight module 20 includes a substrate 30 and a plurality of light-emitting devices 40 .

[0153] Exemplarily, the light emitting device 40 may be an LED light emitting device, for example, a sub-millimeter light emitting diode (Mini Light Emitting Diode, referred to as Mini LED) with a size of 100 μm to 500 μm, or a micro light emitting diode (Micro Light Emitting Diode, referred to as Micro LED) with a size less than 100 μm, or a larger LED.

[0154] Exemplarily, the plurality of light emitting devices 40 emit light under the control of the substrate 30 .

[0155] It is understandable that there are many ways for the substrate 30 to control the working states of the plurality of light-emitting devices 40 , which can be configured according to actual conditions, and the embodiments of the present disclosure do not limit this.

[0156] In some examples, as shown in FIG6A and FIG6B , the substrate 30 includes a plurality of chips 50 , which may be arranged in multiple rows and columns. One chip 50 is electrically connected to at least one light emitting device 40 .

[0157] For example, as shown in Fig. 6B, one chip 50 is electrically connected to one light emitting device 40. One chip 50 controls the operating state of one light emitting device 40 electrically connected thereto.

[0158] 6A , one chip 50 is electrically connected to a plurality of light emitting devices 40. One chip 50 controls the working states of the plurality of light emitting devices 40 electrically connected thereto.

[0159] It is understandable that each chip 50 works independently, so that different light-emitting devices 40 electrically connected to different chips can be controlled to have different working states.

[0160] For example, when a chip 50 is electrically connected to multiple light-emitting devices 40 , there are multiple ways to electrically connect the multiple light-emitting devices 40 to the chip 50 , which can be set according to actual needs, and the embodiments of the present disclosure do not limit this.

[0161] For example, the plurality of light-emitting devices 40 are electrically connected directly to the same chip 50 .

[0162] For another example, as shown in FIG6A , at least two light-emitting devices 40 are connected in series to form a light-emitting device group 40A, and at least one light-emitting device group 40A is electrically connected to a chip 50 .

[0163] With the above configuration, the chip 50 in the substrate 30 can be used to control the light emission of multiple light emitting devices 40 , thereby conveniently enabling the substrate 30 to control the light emitting devices 40 and ensuring that the backlight module 20 can provide backlight for the display panel 10 .

[0164] In some other examples, as shown in FIG6C , the substrate 30 includes a plurality of driving circuits 60. The plurality of driving circuits 60 may be arranged in a plurality of rows and columns.

[0165] 6C and 6D , a driving circuit 60 is electrically connected to at least one light emitting device 40. The driving circuit 60 transmits a control signal to the light emitting device 40 electrically connected thereto, thereby controlling the light emitting device 40 to emit light.

[0166] For example, as shown in FIG. 6C , one driving circuit 60 is electrically connected to one light emitting device 40 .

[0167] 6D , a driving circuit 60 is electrically connected to a plurality of light emitting devices 40. The plurality of light emitting devices 40 may be connected in series.

[0168] The above arrangement can utilize multiple driving circuits 60 on the substrate 30 to control multiple light-emitting devices 40 to emit light, so that the backlight module 20 can provide backlight for the display panel, and the structure of the substrate 30 is simple, which facilitates the preparation of the substrate 30 and the backlight module 20.

[0169] At present, common display device types can generally be divided into LCOS (Liquid Crystal On Silicon) display devices, OLEDOS (Organic Light Emitting Diode On Silicon) display devices, DLP (Digital Light Procession) display devices, Micro-LED direct display devices, etc. The inventors summarized the characteristics of the above four types of display devices and obtained Figure 7.

[0170] It can be seen that the advantages of Micro-LED direct display devices are more obvious. The display screen has high brightness, fast response speed, relatively simple structure and long life.

[0171] In addition, compared with OLED display devices, LCD display devices consume more power. Generally speaking, the power consumption of LCD display devices is four times that of OLED display devices. The main reason is that in LCD display devices, the light-emitting devices in the backlight module are LED light-emitting devices. Compared with the OLED light-emitting devices in OLED display devices, the light emitted by LED light-emitting devices is more divergent and the light extraction efficiency is lower, which makes the backlight module and display device consume more power. Especially in the field of near-eye display, in order to improve the display effect, the backlight module generally needs to provide a single-polarization and high-brightness backlight for the display panel.

[0172] However, as the resolution of near-eye display devices or display products continues to increase, the transmittance of the display panel in the display device has been greatly reduced (for example, reduced to less than half of its original value). As a result, the brightness of the backlight provided by the backlight module after passing through the display panel has also been reduced by about half. In addition, the backlight provided by the backlight module needs to pass through a polarizer, which absorbs some of the light, further reducing the display brightness of the display device. Therefore, it is urgent to provide a high-brightness single-polarization state light-emitting device and backlight module to reduce display power consumption.

[0173] Based on this, some embodiments of the present disclosure provide a light-emitting device. As shown in FIG8 , the light-emitting device 40 includes: a first light conversion layer 41 , an epitaxial structure 42 , and at least one metal wire grid 43 .

[0174] For example, the number of the metal wire grid 43 in the light emitting device 40 may be one or more.

[0175] For the convenience of description, the following description will be made by taking an example where the light emitting device 40 includes a metal wire grid 43 .

[0176] In some examples, epitaxial structure 42 is located on first light conversion layer 41. Metal wire grid 43 is located on epitaxial structure 42. For example, metal wire grid 43 is located on a surface of epitaxial structure 42 that is away from first light conversion layer 41. That is, epitaxial structure 42 is located between first light conversion layer 41 and metal wire grid 43.

[0177] The epitaxial structure 42 is used to emit light. The light emitted by the epitaxial structure 42 can be directed toward the metal wire grid 43 or toward the first light conversion layer 41 .

[0178] For example, as shown in FIG8 , the epitaxial structure 42 may include a first semiconductor layer 421, a light-emitting layer 422, and a second semiconductor layer 423. The first semiconductor layer 421 is located on one side of the metal wire grid 43. The light-emitting layer 422 is located on a side of the first semiconductor layer 421 away from the metal wire grid 43. The second semiconductor layer 423 is located on a side of the light-emitting layer 422 away from the metal wire grid 43.

[0179] Optionally, the material of the first semiconductor layer 421 may be n-GaN (n-type gallium nitride), the material of the light-emitting layer 422 may be multiple quantum wells (MQW), and the material of the second semiconductor layer 423 may be p-GaN (p-type gallium nitride).

[0180] For example, different voltages are applied to the first semiconductor layer 421 and the second semiconductor layer 423 , generating a voltage difference between the first semiconductor layer 421 and the second semiconductor layer 423 . The light emitting layer 422 emits light under the action of the voltage difference, for example, the light is natural light.

[0181] Exemplarily, the metal wire grid 43 may be a single wire grid structure or a double wire grid structure.

[0182] For example, the light emitted by the above-mentioned epitaxial structure 42 may include a first type of light and a second type of light, and the polarization direction of the first type of light is perpendicular to the light transmission axis direction of the metal wire grid 43. Here, taking the light transmission axis direction of the metal wire grid 43 as the first direction X as an example, the first type of light may be light along the transverse magnetic field (Transvers Magnetic) direction, and the first type of light may be referred to as TM light. The polarization direction of the second type of light is parallel to the light transmission axis direction of the metal wire grid 43. Here, taking the light transmission axis direction of the metal wire grid 43 as the first direction X as an example, the second type of light may be light along the transverse electric field (Transvers Electric) direction, and the second type of light may be referred to as TE light. TM light can be emitted through the metal wire grid 43, and TE light is reflected by the metal wire grid 43.

[0183] Therefore, the metal wire grid 43 can be used to filter the light emitted by the epitaxial structure 42, so that the polarization directions of the light emitted from the metal wire grid 43 in the light-emitting device 40 are roughly the same, so that the light-emitting device 40 can be used to provide single-polarization light for the backlight module 20, so that the display panel displays the picture under the single-polarization light provided by the backlight module, thereby improving the display effect of the display device 1.

[0184] Exemplarily, the spacing between metal patterns (eg, the first metal pattern or the second metal pattern mentioned below) in the metal wire grid 43 is at a sub-wavelength level, so that the metal wire grid 43 has certain polarization characteristics within the visible light wavelength range.

[0185] Illustratively, the first light conversion layer 41 is at least partially opposite to the epitaxial structure 42 , so that light emitted by the epitaxial structure 42 can be incident on the first light conversion layer 41 .

[0186] For example, as shown in FIG9 to FIG11 , the structure of the light emitting device 40 may be a flip-chip structure, a face-up structure, or a vertical structure.

[0187] It is understandable that when the structures of the light emitting devices 40 are different, the relative positional relationship between the first light conversion layer 41 and the epitaxial structure 42 in each light emitting device 40 is also different.

[0188] Taking the plane where the metal wire grid 43 is located as the reference plane, when the structure of the light-emitting device 40 is a vertical structure, for example, as shown in Figure 9, the vertical projection of the epitaxial structure 42 on the reference plane is within the vertical projection range of the first light conversion layer 41 on the reference plane.

[0189] For another example, as shown in FIG11 , when the light emitting device 40 has a vertical structure, the orthographic projection of the epitaxial structure 42 on the reference plane substantially coincides with the orthographic projection of the first light conversion layer 41 on the reference plane.

[0190] For another example, as shown in FIG10 , when the structure of the light emitting device 40 is a flip-chip structure, the orthographic projection of the first light conversion layer 41 on the reference plane is within the orthographic projection range of the epitaxial structure 42 on the reference plane.

[0191] In some examples, as shown in Figure 8, the first light conversion layer 41 is configured to change the traveling direction of part of the light incident on the first light conversion layer 41, so that the light after the traveling direction is changed is emitted in a direction toward the metal wire grid 43, and the polarization direction of at least a part of the light after the traveling direction is changed is changed.

[0192] It should be noted that the dotted arrows in FIG. 8 illustrate the approximate travel path of at least a portion of the light emitted by the epitaxial structure.

[0193] Illustratively, a portion of the light incident on the first light conversion layer 41 changes its direction of travel and the polarization direction of at least a portion of the light under the action of the first light conversion layer 41, and is then reflected by the first light conversion layer 41. For example, the incident direction of the portion of the light incident on the first light conversion layer 41 is approximately along the epitaxial structure 42 toward the first light conversion layer 41, and the exit direction of the portion of the light after reflection from the first light conversion layer 41 is approximately along the first light conversion layer 41 toward the metal wire grid 43.

[0194] Furthermore, the polarization direction of a portion of the light incident on the first light conversion layer 41 can be parallel to the transmission axis of the metal wire grid 43. However, the polarization direction of at least a portion of the light emitted through the first light conversion layer 41 is altered. For example, the polarization direction of at least a portion of the light can form an angle with the transmission axis of the metal wire grid 43. For example, the polarization direction of at least a portion of the light can form an angle of 90° with the transmission axis of the metal wire grid 43, i.e., the polarization direction of at least a portion of the light can be perpendicular to the transmission axis of the metal wire grid 43. As a result, at least a portion of the light can be transmitted through the metal wire grid 43 and emitted. It will be understood that the light incident on the first light conversion layer 41 includes TE light, which can be converted to TM light after passing through the first light conversion layer 41, thereby being able to be emitted through the metal wire grid 43.

[0195] It is understood that the light incident on the first light conversion layer 41 may include: light emitted by the epitaxial structure 42 and directly incident on the first light conversion layer 41, light emitted from the epitaxial structure 42 and then incident on the metal wire grid 43, and then reflected by the metal wire grid 43 and incident on the first light conversion layer 41, and light emitted from the epitaxial structure 42 and then incident on the first light conversion layer 41 through other film layers (such as the second light conversion layer mentioned below). In this way, part of the light incident on the first light conversion layer 41 can be incident on the metal wire grid 43 again through the epitaxial structure 42 and then emitted from the metal wire grid 43, thereby improving the utilization rate of the light emitted by the epitaxial structure 42, reducing the light consumption of the light-emitting device 40, improving the luminous efficiency of the backlight module, and reducing the power consumption of the display device.

[0196] Some embodiments of the present disclosure provide a light-emitting device 40, which includes a first light conversion layer 41, an epitaxial structure 42 and at least one metal wire grid 43 stacked in sequence. The first light conversion layer 41 can change the direction of travel of the incident light and change the polarization direction of the incident light, so that the direction of the light emitted from the first light conversion layer 41 is along the direction toward the metal wire grid, so that among the light emitted by the epitaxial structure 42, the TM light incident on the metal wire grid 43 is emitted through the metal wire grid, and the TE light incident on the metal wire grid 43 is reflected by the metal wire grid to the first light conversion layer 41. The TE light is changed in direction by the first light conversion layer 41, and its polarization direction is changed by the first light conversion layer 41 before it is incident on the metal wire grid 43 again, and then emitted from the metal wire grid. As a result, the light-emitting device 40 can emit single-polarization, high-brightness light, and can improve the light-emitting efficiency of the light-emitting device 40, reduce the light consumption of the light-emitting device 40, avoid the light reflected from the metal wire grid 43 from being consumed, and reduce the utilization rate of the light emitted by the epitaxial structure 42. Therefore, when the light-emitting device 40 is applied to a backlight module and a display device, the backlight module can provide a single-polarization, high-brightness light to the display panel, thereby improving the light-emitting efficiency of the backlight module, reducing the power consumption of the backlight module and the display device, and improving the display effect of the display device.

[0197] It is understood that there are various ways to achieve single-polarization light emission from the light-emitting device 40. For example, a polarizer can be provided on the epitaxial structure 42 of the light-emitting device 40. The embodiments of the present disclosure use a metal wire grid 43 as the polarization structure. The metal wire grid 43 has excellent light polarization and can be directly integrated into the epitaxial structure 42. This reduces the dependence of the light-emitting device 40 on the supply chain for producing polarizers and other components during its production process, and can improve the production capacity of the light-emitting device 40.

[0198] It is understandable that there are various structures of the metal wire grid 43 , which can be selected and set according to actual needs, and the present disclosure does not limit this.

[0199] Some embodiments of the present disclosure provide a metal wire grid 43 having a dual wire grid structure. As shown in FIG12 , the metal wire grid 43 includes a first metal layer 431 , a light-transmitting dielectric layer 432 , and a second metal layer 433 .

[0200] In some examples, the first metal layer 431 includes a plurality of first metal patterns 4301. Each first metal pattern 4301 extends along a first direction X, and the plurality of first metal patterns 4301 are arranged at intervals along a second direction Y. The first direction X intersects the second direction Y. For example, the angle between the first direction X and the second direction Y is 85°, 90°, 95°, 100°, or 105°.

[0201] For the convenience of description, the embodiments of the present disclosure are described by taking the included angle between the first direction X and the second direction Y as 90° as an example.

[0202] For example, there is a gap between any two adjacent first metal patterns 4301 , and any two adjacent first metal patterns 4301 are parallel to each other.

[0203] For example, as shown in FIG. 8 , the first metal layer 431 may be located on a side of the first semiconductor layer 421 away from the second semiconductor layer 423 .

[0204] In some examples, the light-transmitting medium layer 432 includes a plurality of light-transmitting medium patterns 4302. Each light-transmitting medium pattern 4302 extends along a first direction X, and the plurality of light-transmitting medium patterns 4302 are arranged along a second direction Y at intervals.

[0205] Exemplarily, the light-transmitting medium pattern 4302 is located between two adjacent first metal patterns 4301 .

[0206] For example, the light-transmitting medium pattern 4302 separates two adjacent first metal patterns 4301 .

[0207] In some examples, the second metal layer 433 includes a plurality of second metal patterns 4303 . Each second metal pattern 4303 extends along the first direction X, and the plurality of second metal patterns 4303 are arranged at intervals along the second direction Y. A second metal pattern 4303 is located on a surface of a light-transmitting medium pattern 4302 on a side close to the first semiconductor layer 421 .

[0208] Illustratively, the plurality of second metal patterns 4303 correspond one-to-one to the plurality of light-transmitting medium patterns 4302 .

[0209] The inventors of the present invention have simulated the effects of a metal wire grid with a single wire grid structure and a metal wire grid with a double wire grid structure on the polarization and transmittance of light emitted by a light-emitting device, and obtained the transmittance, reflectivity and absorptivity of the metal wire grid through simulation calculations.

[0210] The metal wire grid 43 of the double wire grid structure is shown in FIG12 .

[0211] The simulation conditions of the inventor's simulation of the metal wire grid 43 of the double-wire grid structure are that a planar light source emits light in the substrate 01, and the wavelength range of the emitted light is within 450nm~470nm. The material of the substrate 01 can be selected from silicon dioxide (SiO2) or gallium nitride (GaN), where the refractive index of SiO2 is 1.5 and the refractive index of GaN is 2.4. The transmittance, absorptivity and reflectivity of the TM light and TE light emitted through the metal wire grid 43 are simulated and calculated, and Figures 13 and 14 are obtained.

[0212] As shown in Figure 13 , the transmittance of the wire grid 43 for TE light is almost zero, meaning that almost no TE light can be emitted through the wire grid 43. The wire grid 43 has an absorptivity of approximately 0.17 and a reflectivity of approximately 0.83 for TE light. In other words, of the TE light incident on the wire grid 43, approximately 83% is reflected by the wire grid 43, while approximately 17% is absorbed by the wire grid 43.

[0213] As shown in Figure 14 , the reflectivity of the metal wire grid 43 for TM light is almost zero, meaning that the metal wire grid 43 reflects almost no TM light. The metal wire grid 43 also has an absorptivity of approximately 0.17 for TM light and a transmittance of approximately 0.83 for TM light. In other words, approximately 83% of the TM light incident on the metal wire grid 43 is transmitted through the metal wire grid 43, while approximately 17% of the TE light is absorbed by the metal wire grid 43.

[0214] It can be seen from this that the metal wire grid 43 can absorb a portion of the light, and the metal wire grid 43 can only transmit TM light, with a transmittance of TM light greater than 80%. The metal wire grid 43 can reflect most of the TE light, and the reflectance of TE light is greater than 80%. Therefore, the TE light reflected by the metal wire grid 43 can be incident on the first light conversion layer 41, and the first light conversion layer 41 changes the direction of travel and polarization direction, so that the light with changed polarization direction is incident on the metal wire grid 43 again and is emitted through the metal wire grid 43, thereby avoiding the light reflected by the metal wire grid 43 from being effectively utilized. Therefore, in the embodiment of the present disclosure, the metal wire grid 43 with the above-mentioned double wire grid structure is used as a polarization structure to filter the light emitted by the epitaxial structure, so that the light emitting device 40 can emit single-polarization, high-brightness light, and can improve the light extraction efficiency of the light emitting device 40 and reduce the power consumption of the backlight module 20.

[0215] It should be noted that the key structural parameters of the metal wire grid of the dual wire grid structure include: line width, repetition period, etc. Among them, the line width refers to the width of the first metal pattern (or second metal pattern) in the direction perpendicular to its extension direction. Taking the first metal pattern and the second metal pattern as an example with the same size, as shown in Figure 12, the line width is the size of the first metal pattern in the second direction Y. The repetition period refers to the spacing between the repetitions of the second metal pattern (or the first metal pattern) in the direction perpendicular to its extension direction, as shown in Figure 12. The repetition period here is the grating period of the metal wire grid.

[0216] The metal wire grid 43 of the single wire grid structure is shown in Figure 15. It should be noted that the metal wire grid includes a plurality of light-transmitting medium patterns 432' arranged at intervals, and a second metal pattern 433' located on the light-transmitting medium patterns.

[0217] Specifically, the structural parameters of the metal wire grid of the single-wire grid structure and the metal wire grid of the double-wire grid structure are roughly the same. For example, the wavelength of the light provided to the metal wire grid of the single-wire grid structure and the metal wire grid of the double-wire grid structure are both 450nm~470nm, the line width of the metal wire grid of the single-wire grid structure (here the line width refers to the size of the second metal pattern 433' along the second direction) and the line width of the metal wire grid of the double-wire grid structure (here the line width refers to the size of the second metal pattern 4303 along the second direction) are the same, both of which are 60nm, the repetition period P' of the second metal pattern of the metal wire grid of the single-wire grid structure in the second direction and the repetition period P' of the second metal pattern of the metal wire grid of the double-wire grid structure in the second direction are The repetition period P in the two directions is equal, both 120nm; the thickness of the transparent dielectric pattern of the metal wire grid of the single-wire grid structure is the same as the thickness of the transparent dielectric pattern of the metal wire grid of the double-wire grid structure, both 80nm; the refractive index of the transparent dielectric pattern of the metal wire grid of the single-wire grid structure is the same as the refractive index of the transparent dielectric pattern of the metal wire grid of the double-wire grid structure, both 1.5; the material of the metal pattern of the metal wire grid of the wire grid structure is the same as the material of the first metal pattern (or second metal pattern) of the metal wire grid of the double-wire grid structure, both aluminum; the light source is incident on the metal wire grid of the single-wire grid structure and the metal wire grid of the double-wire grid structure respectively through a buffer material with a refractive index of 1.5. After simulation, the transmittance and polarization degree of the metal wire grid of the single-wire grid structure and the metal wire grid of the double-wire grid structure are calculated and plotted as Figures 16 and 17.

[0218] In Figure 16, WGP1 represents the transmittance of light incident on the metal wire grid of a single wire grid structure, and WGP2 represents the transmittance of light incident on the metal wire grid of a dual wire grid structure. Since the simulation results above have confirmed that TE light is almost unable to pass through the metal wire grid, the transmittance of light incident on the metal wire grid can be considered as the transmittance of TM light within the light incident on the metal wire grid.

[0219] Figure 16 shows that the transmittance of the wire grid remains essentially unchanged depending on the wavelength of the incident light. The transmittance of the wire grids with a single wire grid structure and the dual wire grid structure is essentially the same, both around 0.80. The single wire grid and the dual wire grid structures have virtually no effect on the transmittance.

[0220] In Figure 17, WGP1 represents the polarization degree of light emitted from the metal wire grid of a single wire grid structure, and WGP2 represents the polarization degree of light emitted from the metal wire grid of a dual wire grid structure. The polarization degree here refers to the ratio of the difference between the TM light and the TE light emitted from the metal wire grid to the sum of the TM light and the TE light emitted from the metal wire grid.

[0221] As shown in Figure 17, the polarization degree of the light emitted by the metal wire grid remains essentially unchanged regardless of the wavelength of the incident light. The polarization degree of the metal wire grid with a single wire grid structure is approximately 0.918, while the polarization degree of the metal wire grid with a dual wire grid structure is approximately 0.999. The dual wire grid structure has a higher polarization degree.

[0222] Therefore, in some embodiments of the present disclosure, the light-emitting device 40 is provided with a metal wire grid 43 having a double-wire grid structure, so that the polarization degree of the metal wire grid 43 can be greater than 0.99. When the metal wire grid 43 is applied to the light-emitting device 40, the polarization degree of the light emitted by the light-emitting device 40 can be improved, and the light-emitting device can provide more precise single-polarization light, which can further improve the display effect of the display device.

[0223] In some embodiments, the light emitting device 40 includes two metal wire grids 43 .

[0224] In some examples, as shown in FIG18 , the two metal wire grids 43 are both double-wire-grid structures. The two metal wire grids 43 are stacked on the epitaxial structure 42. The two metal wire grids 43 are connected together via a connection layer.

[0225] For example, the two metal wire grids 43 form a first metal wire grid group.

[0226] The inventors simulated the stacking design of the two metal wire grids 43 and obtained the transmittance, absorptivity and polarization degree of the first metal wire grid group, and plotted them as shown in FIG19 .

[0227] As can be seen from FIG. 19 , in the case of a stacked design of two metal wire grids 43 of a double-wire grid structure, the TM light transmittance of the first metal wire grid group is about 0.60, and the polarization degree is close to 1.

[0228] Therefore, when the light emitting device 40 includes two metal wire grids 43 of a double wire grid structure, the polarization degree of light emitted by the light emitting device can be made higher.

[0229] In other examples, as shown in FIG20 , the two metal wire grids 43 are both single wire grid structures. The two metal wire grids 43 are stacked on the epitaxial structure 42. The two metal wire grids 43 are connected together via a connection layer.

[0230] For example, the two metal wire grids 43 constitute a second metal wire grid group.

[0231] The inventors simulated the stacking design of the two metal wire grids 43 and obtained the transmittance, absorptivity and polarization degree of the second metal wire grid group, and plotted them as shown in FIG21.

[0232] As can be seen from FIG. 21 , in the case of a stacked design of two metal wire grids 43 of a single wire grid structure, the polarization degree of the second metal wire grid group is close to 1.

[0233] Therefore, when the light emitting device 40 includes two metal wire grids 43 of a single wire grid structure, the polarization degree of light emitted by the light emitting device can be higher, and the manufacturing process of the light emitting device can be simplified.

[0234] For example, when both metal wire grids 43 have a single wire grid structure, the metal wire grid structure can also be arranged in other ways. For example, as shown in FIG22 , the metal patterns of the two metal wire grids are arranged in an interlaced manner. This can improve the production yield of the metal wire grid, avoid interconnection between the metal patterns of the metal wire grids, and avoid affecting the transmittance and polarization degree of the metal wire grids.

[0235] The inventor simulated the situation of the two metal wire grids in Figure 22 above, calculated their polarization degree and transmittance, and compared them with the transmittance and polarization degree of a metal wire grid with a double wire grid structure shown in Figure 12 in the above embodiment of the present disclosure, and obtained Figures 23 and 24.

[0236] In Figure 23, T_TM represents the transmittance of TM light through the metal wire grid in Figure 12, and T_TM_S represents the transmittance of TM light through the metal wire grid in Figure 22. In Figure 24, PE represents the polarization degree of the metal wire grid in Figure 12, and PE_S represents the polarization degree of the metal wire grid in Figure 22. As shown in Figures 23 and 24, the transmittance of T_TM_S decreases by more than 10% compared to T_TM, and PE_S fluctuates significantly with changes in the incident wavelength.

[0237] In addition, the inventors simulated the relationship between the alignment accuracy between the two metal wire grids in FIG. 22 and their transmittance and polarization degree, and found that the alignment accuracy between the two metal wire grids had no effect on the transmittance and polarization degree.

[0238] Therefore, in some embodiments of the present disclosure, the light emitting device includes the metal wire grid 43 of the double wire grid structure, so that the light emitting device 40 can have higher light extraction efficiency and light polarization.

[0239] In some examples, as shown in FIG12 , in the metal wire grid 43, the thickness of the light-transmitting dielectric pattern 4302 is greater than the thickness of the first metal pattern 4301. The second metal pattern 4303 is not connected to the adjacent first metal pattern 4301, and a gap exists between the second metal pattern 4303 and the first metal pattern 4301. This allows light emitted by the light-emitting layer 422 to pass through the gap and the light-transmitting dielectric layer 432 through the metal wire grid 43, thereby improving the transmittance of the metal wire grid 43, increasing the brightness of the light-emitting device 40, and improving the light extraction efficiency of the light-emitting device 40.

[0240] It should be noted that the thickness of the transparent medium pattern 4302 refers to the dimension of the transparent medium pattern 4302 along the Z direction as shown in Figure 12. Similarly, the thickness of the first metal pattern 4301 refers to the dimension of the first metal pattern 4301 along the Z direction as shown in Figure 12.

[0241] It is understandable that the shape of the light-transmitting medium pattern 4302 can be selected and set according to actual conditions, and the present disclosure does not impose any limitation on this.

[0242] In some embodiments, as shown in FIG25 , the cross-sectional shape of the light-transmitting medium pattern 4302 includes an inverted trapezoid in a direction perpendicular to the plane of the metal wire grid 43 and along the second direction Y. The angle θ between the side and the bottom of the inverted trapezoid is less than or equal to 90°.

[0243] Since the second metal pattern 4303 is located on the transparent medium pattern 4302, the cross-sectional shape of the above-mentioned transparent medium pattern 4302 is set to include an inverted trapezoid. In the process of making the second metal pattern 4303, the risk of the material of the second metal layer climbing on the side wall of the transparent medium pattern 120 can be reduced, and the risk of the second metal pattern 4303 contacting the adjacent first metal pattern 4301 along the side wall of the transparent medium pattern 4302 is reduced. To a certain extent, the disconnection between the first metal pattern 4301 and the second metal pattern 4303 can be guaranteed, thereby increasing the transmittance of the metal wire grid 43 and reducing the absorption rate of the metal wire grid 43, thereby improving the polarization degree of the light-emitting device 40 and improving the light output efficiency of the light-emitting device 40 and the backlight module.

[0244] It is understood that in the metal wire grid 43 shown in FIG25 , due to process errors and other factors, the cross-sectional shape of the light-transmitting medium pattern 4302 may not be a sharp-edged inverted trapezoid. For example, the top or bottom angles of the inverted trapezoid may be rounded or approximately rounded (not shown in FIG25 ). Furthermore, the inverted trapezoidal shape described above is related to the viewing angle of the metal wire grid 43 or the placement of the metal wire grid 43. For example, in the cross-sectional view of the metal wire grid 43 shown in FIG25 , the inverted trapezoidal shape refers to the cross-sectional shape of the light-transmitting medium pattern 4302 in the metal wire grid 43, when viewed from the direction from the second metal pattern 4303 to the first metal pattern 4301.

[0245] The inventors modeled and simulated the effects of different cross-sectional shapes of the transparent medium patterns 4302 in the metal wire grid 43 along the direction perpendicular to the plane of the metal wire grid 43 and along the second direction Y on the transmittance and polarization degree of the metal wire grid 43 using FDTD (Finite Different Time Domain) software.

[0246] Specifically, the simulation parameters are as follows: the cross-sectional shapes of the light-transmitting medium pattern 4302 are set to be a first inverted trapezoid Fab1, a second inverted trapezoid Fab2, an inverted triangle Fab3, and a rectangle Fab4, respectively. The wavelength of light incident on the metal wire grid is set to be within the range of 450 nm to 470 nm. The transmittance and polarization degree of the four metal wire grids are simulated and calculated, and plotted as Figures 27 and 28. Specifically, the angle θ between the side and the bottom base of the first inverted trapezoid Fab1 is 67°, the angle between the side and the bottom base of the second inverted trapezoid Fab2 is 75°, the angle θ between the side and the bottom base of the inverted triangle Fab3 (as shown in Figure 26) is 80°, and the angle θ between the side and the bottom base of the rectangle Fab4 (as shown in Figure 12) is 90°.

[0247] As shown in Figure 27, the transmittance of the four metal wire grids is similar, ranging from 0.8 to 0.85. This shows that the different cross-sectional shapes of the transparent medium patterns have little effect on the transmittance of the metal wire grids.

[0248] As can be seen from Figure 28, when the cross-sectional shape of the light-transmitting medium pattern 4302 is different, the polarization degree of the four metal wire grids has a small change, and the polarization degree changes by about 0.02% to 0.03%. The smaller the angle between the side and the bottom of the cross-sectional shape, the greater the polarization degree of the light output of the metal wire grid 43. Therefore, in the preparation process of the metal wire grid, the cross-sectional shape of the light-transmitting medium pattern can be set to an irregular shape (that is, non-rectangular) or an inverted trapezoid. Within the scope of process feasibility, the angle between the side and the bottom of the irregular shape is made smaller, thereby improving the polarization degree of the light output of the metal wire grid to a certain extent.

[0249] In some examples, the material of the first metal pattern 4301 and the material of the second metal pattern 4303 may be the same.

[0250] For example, the material of either the first metal pattern 4301 or the second metal pattern 4303 may be a metal material such as aluminum (Al), silver (Ag), gold (Au), or copper (Cu).

[0251] Using the above metal materials to form the first metal layer 431 and the second metal layer 433 can make the metal wire grid 43 have a lower absorptivity and a higher transmittance, thereby improving the light extraction efficiency and polarization degree of the light emitting device 40 .

[0252] For example, the material of the first metal pattern 4301 and the material of the second metal pattern 4303 can both be aluminum. Since aluminum has a high transmittance, a low absorptivity, and a low cost compared to other metal materials for light within the visible wavelength range, using aluminum as the material of the first metal pattern 4301 and the second metal pattern 4303 can further increase the transmittance and reduce the absorptivity of the metal wire grid 43, thereby improving the light extraction efficiency and polarization degree of the light-emitting device 40. It also significantly reduces the manufacturing cost of the metal wire grid 43, thereby reducing the cost of the light-emitting device 40 and the backlight module.

[0253] Taking the example of a case where the material of the first metal layer is the same as that of the second metal layer, the inventors simulated a metal wire grid 43 formed of aluminum (Al), silver (Ag), and copper (Cu), calculated the transmittance, absorptivity, and reflectivity of the metal wire grid, and plotted them as shown in Figures 29 to 31. The light-emitting device has a wavelength of 450 nm to 470 nm, and the dimension of the first metal pattern (or second metal pattern) in the second direction is 60 nm.

[0254] In Figure 29, the transmittances of the wire grids formed of aluminum and silver are similar, both ranging from 0.55 to 0.70. However, when the wire grid is formed of copper, the transmittance is relatively low, at around 0.20.

[0255] In Figure 30 , when aluminum is used to form the metal wire grid, the metal wire grid has the lowest absorptivity, ranging from 0.10 to 0.125. When copper is used to form the metal wire grid, the metal wire grid has the highest absorptivity, slightly greater than 0.70. When silver is used to form the metal wire grid, the metal wire grid has an intermediate absorptivity, ranging from 0.350 to 0.425.

[0256] In Figure 31 , when aluminum is used to form the metal wire grid, the reflectivity of the metal wire grid is the highest, approximately 0.25. When copper is used to form the metal wire grid, the reflectivity is intermediate, slightly greater than 0.075. When silver is used to form the metal wire grid, the reflectivity of the metal wire grid is the lowest, close to 0.

[0257] As can be seen, when aluminum and silver are used as the material for the first metal layer (or second metal layer) of the metal wire grid, the transmittance of the metal wire grid is relatively high and the difference between the two is not significant. However, when aluminum is used as the material for the first metal layer (or second metal layer) of the metal wire grid, the absorptivity of the metal wire grid is the lowest. When aluminum is used as the material for the first metal layer (or second metal layer) of the metal wire grid, the reflectivity of the metal wire grid is the highest. Moreover, aluminum is less expensive than silver.

[0258] Therefore, selecting aluminum as the material of the first metal layer (or second metal layer) of the metal wire grid 43 can improve the transmittance of the metal wire grid 43, thereby improving the light extraction efficiency of the light-emitting device 40, and can also reduce the absorptivity of the metal wire grid 43, thereby reducing the light consumption of the light-emitting device 40, and can also improve the reflectivity of the metal wire grid 43, so that light that cannot pass through the metal wire grid 43 can be reflected through the metal wire grid 43 to structures such as the first light conversion layer 41, thereby improving the utilization rate of the light emitted by the epitaxial structure 42, thereby further improving the light extraction efficiency of the light-emitting device 40.

[0259] In some embodiments, as shown in FIG. 12 , a dimension of the first metal pattern 4301 along the second direction Y is substantially equal to a dimension of the second metal pattern 4303 along the second direction Y.

[0260] For example, when viewed from above, each first metal pattern 4301 may be in the shape of an elongated strip, and the size of the first metal pattern 4301 in the second direction Y refers to the average size of the elongated strip in the width direction. Similarly, when viewed from above, each second metal pattern 4303 may also be in the shape of an elongated strip, and the size of the second metal pattern 4303 in the second direction Y refers to the average size of the elongated strip in the width direction.

[0261] This arrangement allows the first metal pattern 4301 and the second metal pattern 4303 to have approximately the same shape, resulting in a more regular shape. This, in turn, facilitates and reduces the difficulty of fabricating the metal wire grid 43. Furthermore, this arrangement allows the first metal pattern 4301 and the second metal pattern 4303 to cooperate with each other to filter light of a specific polarization direction, thereby improving the polarization degree of light emitted from the metal wire grid 43.

[0262] In some embodiments, as shown in FIG. 12 , the thickness of the first metal pattern 4301 is substantially equal to the thickness of the second metal pattern 4303 .

[0263] When the materials of the first metal pattern and the second metal pattern are the same, the above method can be used to simultaneously form the first metal layer 431 and the second metal layer 433 (or the first metal pattern 4301 and the second metal pattern 4303) in one preparation process, thereby reducing the difficulty of preparing the metal wire grid 43 and the light-emitting device 40.

[0264] In some embodiments, the thickness of the first metal pattern 4301 ranges from 20 nm to 80 nm; and / or the thickness of the second metal pattern 4303 ranges from 20 nm to 80 nm.

[0265] In some examples, the thickness of the first metal pattern 4301 ranges from 20 nm to 80 nm.

[0266] Exemplarily, the thickness of the first metal pattern 4301 may range from 20 nm to 80 nm, or from 50 nm to 60 nm, or from 20 nm to 60 nm, or from 60 nm to 80 nm, etc.

[0267] For example, the thickness of the first metal pattern 4301 may be 20 nm, 50 nm, 55 nm, 60 nm, or 80 nm.

[0268] In some other examples, the thickness of the second metal pattern 4303 ranges from 20 nm to 80 nm.

[0269] In some examples, the thickness of the second metal pattern 4303 ranges from 20 nm to 80 nm.

[0270] Exemplarily, the thickness of the second metal pattern 4303 may range from 20 nm to 80 nm, or from 50 nm to 60 nm, or from 20 nm to 60 nm, or from 60 nm to 80 nm, etc.

[0271] For example, the thickness of the second metal pattern 4303 may be 20 nm, 40 nm, 55 nm, 60 nm, or 80 nm.

[0272] In some other examples, the thickness of the first metal pattern 4301 ranges from 20 nm to 80 nm, and the thickness of the second metal pattern 4303 ranges from 20 nm to 80 nm.

[0273] For example, the thickness range of the first metal pattern 4301 and the thickness range of the second metal pattern 4303 may be the same or different.

[0274] In the following, an example is given in which the thickness of the first metal pattern 4301 is the same as that of the second metal pattern 4303 , and the material of the first metal pattern 4301 is the same as that of the second metal pattern 4303 .

[0275] The inventors simulated the metal wire grid 43 formed with different first metal pattern thicknesses, calculated the transmittance, absorptivity, and reflectivity of the metal wire grid 43, and plotted them in Figures 32, 33, 34, and 35. Aluminum was used as the material for the first metal layer (or second metal layer), the wavelength of light incident on the metal wire grid 43 was in the range of 450nm to 470nm, the line width of the metal wire grid 43 was 60nm, the repetition period of the second metal pattern was 120nm, and the thickness of the first metal pattern was in the range of 20nm to 140nm.

[0276] As shown in Figures 32 to 34, when the thickness of the first metal pattern ranges from 20nm to 80nm, the transmittance of the metal wire grid 43 is greater than 0.55, the absorptivity of the metal wire grid 43 is less than 0.20, and the reflectivity of the metal wire grid 43 is between 0.20 and 0.35.

[0277] As shown in Figures 32 to 34 , when the wavelength of light incident on the metal wire grid 43 is in the range of 450 nm to 470 nm, varying the thickness of the first metal pattern results in a linear relationship between the transmittance, absorptivity, and reflectivity of the metal wire grid 43 and the wavelength of the light incident on the metal wire grid 43. Therefore, the relationship between the transmittance, reflectivity, and absorptivity of the metal wire grid 43 and the thickness of the first metal pattern at a wavelength of 460 nm was investigated, resulting in Figure 35 .

[0278] As shown in Figure 35, as the thickness of the first metal pattern increases, the transmittance of the metal wire grid 43 first increases to approximately 0.65, then decreases to approximately 0.02, and finally increases. As the thickness of the first metal pattern increases, the reflectivity of the metal wire grid 43 first increases, gradually increasing to approximately 0.67, then decreases to approximately 0.10. As the thickness of the first metal pattern increases, the absorption of the metal wire grid 43 first slowly decreases to approximately 0.1, then increases to approximately 0.30, and then begins to decrease.

[0279] Therefore, when the thickness of the first metal pattern is within the range of 20nm to 80nm, especially when the thickness of the first metal pattern is 50nm, the metal wire grid 43 has a higher transmittance and a lower absorptivity, thereby improving the light extraction efficiency of the light emitting device.

[0280] In some embodiments, the refractive index of the light-transmitting medium pattern 4302 ranges from 1.4 to 1.5.

[0281] For example, the refractive index of the light-transmitting medium pattern 4302 may be 1.40, 1.42, 1.45, 1.49, or 1.50.

[0282] The inventors simulated the metal wire grid 43 of the transparent medium pattern 4302 with different refractive indices, calculated the transmittance, absorptivity and reflectivity of the metal wire grid 43, and plotted them as shown in Figures 36 to 39.

[0283] In Figures 36 to 38, 1.4 indicates that the refractive index of the light-transmitting medium pattern is 1.4, 1.5 indicates that the refractive index of the light-transmitting medium pattern is 1.5... 2.4 indicates that the refractive index of the light-transmitting medium pattern is 2.4.

[0284] 36 , the smaller the refractive index of the light-transmitting medium pattern 4302, the greater the transmittance of the metal wire grid 43. The larger the refractive index of the light-transmitting medium pattern, the smaller the transmittance of the metal wire grid 43.

[0285] 37 , the smaller the refractive index of the light-transmitting medium pattern 4302, the smaller the absorptivity of the metal wire grid 43. The larger the refractive index of the light-transmitting medium pattern, the larger the absorptivity of the metal wire grid 43.

[0286] 38 , the smaller the refractive index of the light-transmitting medium pattern 4302 , the smaller the reflectivity of the metal wire grid 43 . The larger the refractive index of the light-transmitting medium pattern 4302 , the larger the reflectivity of the metal wire grid 43 .

[0287] As shown in Figures 36 to 38 , when the wavelength of light incident on the metal wire grid 43 is in the range of 450 nm to 470 nm, the transmittance, absorptivity, and reflectivity of the metal wire grid 43 formed by the light-transmitting dielectric patterns 4302 of different refractive indices are substantially linearly related to the wavelength of the light incident on the metal wire grid 43. Therefore, the relationship between the transmittance, reflectivity, and absorptivity of the metal wire grid 43 and the refractive index of the light-transmitting dielectric patterns 4302 at a wavelength of 460 nm was investigated, resulting in Figure 39.

[0288] As shown in Figure 39, as the refractive index of the transparent medium pattern 4302 continues to increase, the transmittance of the metal wire grid 43 decreases from approximately 0.85 to approximately 0.45. As the refractive index of the transparent medium pattern 4302 continues to increase, the absorptivity of the metal wire grid 43 increases from approximately 0.15 to approximately 0.34.

[0289] Therefore, when the refractive index of the transparent medium pattern 4302 is in the range of 1.4 to 1.5, the metal wire grid 43 has a higher transmittance and a lower absorptivity, thereby improving the light extraction efficiency of the light emitting device 40 and reducing the light consumption of the light emitting device 40 .

[0290] For example, the transparent medium pattern 4302 may also be made of a glue or film with a lower refractive index, such as magnesium fluoride (MgF), etc. The refractive index of magnesium fluoride is 1.38.

[0291] It should be noted that, for different light emitting devices 40 in which the wavelength range of light emitted by the epitaxial structure 42 is different, different metal wire grid 43 structures can be set to match the epitaxial structure 42, so that the light extraction efficiency and polarization degree of the metal wire grid 43 are optimized.

[0292] In some embodiments, when the light-emitting device 40 emits blue light, the repetition period of the second metal pattern 4303 in the second direction Y is less than or equal to 140 nm; and / or the thickness range of the light-transmitting medium pattern 4302 is 60 nm to 80 nm; and / or the size range of the light-transmitting medium pattern 4302 in the second direction Y is 50 nm to 70 nm.

[0293] For example, the wavelength range of the blue light may be 450 nm to 470 nm.

[0294] In some examples, when the light emitting device 40 emits blue light, a repetition period of the second metal pattern 4303 in the second direction Y is less than or equal to 140 nm.

[0295] Exemplarily, when the light emitting device 40 emits blue light, the repetition period of the second metal pattern 4303 in the second direction Y is equal to 140 nm.

[0296] Exemplarily, when the light emitting device 40 emits blue light, the repetition period of the second metal pattern 4303 in the second direction Y is less than 140 nm.

[0297] For example, as shown in Figure 12, the spacing between the side wall of the second metal pattern 4303 on the left side along the second direction Y and the side wall of the adjacent second metal pattern on the left side along the second direction Y is the repetition period of the metal wire grid or the repetition period P of the second metal pattern of the metal wire grid.

[0298] It is understood that in the above-mentioned light-emitting device 40, the first metal pattern 4301 also has a repeat period, and the repeat period of the first metal pattern 4301 can be the same as the repeat period of the second metal pattern. Of course, the repeat period of the first metal pattern 4301 can also be different from the repeat period of the second metal pattern. For ease of explanation, the following description uses the example where the repeat period of the first metal pattern is the same as the repeat period of the second metal pattern.

[0299] The inventors simulated a metal wire grid 43 composed of second metal patterns with different repetition periods, setting the line width of the metal wire grid 43 to half the repetition period, the refractive index of the transparent medium pattern to 1.5, the thickness of the transparent medium layer to 80 nm, the thickness of the first metal pattern and the second metal pattern to 60 nm, the wavelength of light incident on the metal wire grid 43 to be in the range of 450 nm to 470 nm, and the planar light source to be able to penetrate the buffer layer to the metal wire grid 43, wherein the buffer layer is 80 nm thick. The transmittance, absorptivity, and reflectivity of the metal wire grid 43 were calculated and plotted as Figures 40 to 43. It can be understood that because the wavelength of the light incident on the metal wire grid 43 is blue light (here, the wavelength of blue light can be in the range of 450 nm to 470 nm), in this simulation, the repetition period of the second metal pattern is less than the wavelength of the blue light.

[0300] In FIG. 40 to FIG. 42 , the numbers 20, 30, ..., 220, 300, etc. on the right side of the line segments indicate that the repetition periods are 20 nm, 30 nm, ..., 220 nm, 300 nm.

[0301] As shown in Figures 40 to 42, the greater the repeat period of the second metal pattern of wire grid 43, the lower the transmittance of wire grid 43. When the repeat period of the second metal pattern of wire grid 43 is greater than 180 nm, the transmittance of wire grid 43 is less than 0.7, and the absorptivity of wire grid 43 is less than 0.20. When the repeat period of the second metal pattern is approximately 260 nm, the absorptivity of wire grid 43 is approximately 35%, resulting in significant light loss. There is a linear relationship between the repeat period of the second metal pattern of wire grid 43 and the reflectivity of wire grid 43.

[0302] In order to explore the relationship between the transmittance, reflectivity and absorptivity of the metal wire grid 43 and the repetition period of the second metal pattern at a wavelength of 460 nm, FIG. 43 is obtained.

[0303] As shown in Figure 43, as the repeat period of the second metal pattern of metal wire grid 43 increases (within the range of 40nm to 300nm), the transmittance of metal wire grid 43 decreases. When the repeat period of the second metal pattern is 300nm, the transmittance of metal wire grid 43 is less than 0.05, and the absorptivity of metal wire grid 43 is approximately 0.25. When the repeat period of the second metal pattern is between 10nm and 140nm, the transmittance of metal wire grid 43 is generally greater than 0.80, and the absorptivity is less than 0.20.

[0304] Therefore, setting the repetition period of the second metal pattern of the metal wire grid 43 to be less than or equal to 140 nm can increase the transmittance of the metal wire grid 43 and reduce the absorptivity, thereby improving the luminous efficiency of the light-emitting device. Furthermore, the repetition period of the second metal pattern of the metal wire grid 43 can be set to approximately 120 nm. This reduces the difficulty of manufacturing the metal wire grid 43 and the light-emitting device while maintaining a certain tolerance, facilitating mass production of the metal wire grid 43.

[0305] Exemplarily, a dimension of the second metal pattern in the second direction is half of a repeating period of the second metal pattern.

[0306] For example, when the repetition period of the second metal pattern of the metal wire grid 43 is 120 nm, the size of the second metal pattern in the second direction is 60 nm.

[0307] For another example, when the repetition period of the second metal pattern of the metal wire grid 43 is 140 nm, the size of the second metal pattern in the second direction is 70 nm.

[0308] By adopting the above-mentioned configuration, the metal wire grid 43 can have a higher transmittance and a lower absorptivity, thereby reducing the light consumption of the light-emitting device and improving the light extraction efficiency of the light-emitting device.

[0309] The inventors simulated different sizes (hereinafter referred to as line width) of the second metal pattern in the second direction, obtained the absorptivity, transmittance and reflectivity of different metal wire grids 43, and plotted them as shown in Figures 44 to 47.

[0310] In Figures 44 to 46, the numbers 10, 20...110, 120, etc. on the right side of the line segments indicate that the sizes of the second metal pattern in the second direction are 10 nm, 20 nm...110 nm, 120 nm, etc., respectively.

[0311] As shown in Figures 44-46, when the wavelength of light incident on the metal wire grid 43 is between 450nm and 470nm, the different line widths of the second metal pattern are linearly correlated with the transmittance, absorptivity, and reflectivity of the metal wire grid 43 it forms. However, the transmittance of the metal wire grid 43 varies significantly with different line widths, fluctuating between 0 and 0.8. Therefore, for a constant repetition period, the line width has a significant impact on the transmittance of the metal wire grid 43. Therefore, during the preparation of the metal wire grid 43, careful attention should be paid to the control of the line width.

[0312] As shown in Figure 47, when the line width of the metal wire grid 43 is within the range of 60nm±10nm, the repetition period of the second metal pattern is 120nm, and the line width of the second metal pattern is approximately 50% of the repetition period, the transmittance of the metal wire grid 43 is greater than 0.7, and the absorptivity is approximately 0.15. Therefore, when the line width of the metal wire grid 43 is set within the range of 60nm±10nm and the line width of the second metal pattern is approximately 50% of the repetition period, the absorptivity of the metal wire grid 43 is low and the transmittance is high, thereby improving the light extraction efficiency of the light-emitting device 40 and reducing the power consumption of the backlight module and display device.

[0313] In other examples, when the light emitting device 40 emits blue light, the thickness of the light-transmitting medium pattern 4302 ranges from 60 nm to 80 nm.

[0314] For example, when the light emitting device 40 emits blue light, the thickness of the light-transmitting medium pattern 4302 may be in the range of 60 nm to 70 nm or 70 nm to 80 nm.

[0315] For example, when the light emitting device 40 emits blue light, the thickness of the light-transmitting medium pattern 4302 may be 60 nm, 65 nm, 70 nm, 77 nm, or 80 nm.

[0316] The inventors simulated the metal wire grid 43 composed of transparent medium patterns of different thicknesses, and set the line width of the metal wire grid 43 to 60nm, the repetition period of the second metal pattern to 120nm, the refractive index of the transparent medium pattern to 1.5, the thickness of the transparent medium layer to 80nm, the thickness of the first metal pattern and the second metal pattern to 60nm, the wavelength range of the light incident on the metal wire grid is 450nm~470nm, the planar light source is emitted to the metal wire grid through the buffer layer, where the thickness of the buffer layer is 80nm, and the transmittance, absorptivity and reflectivity of the metal wire grid are obtained by simulation and calculation, and graphs are obtained as Figures 48 to 51.

[0317] In Figures 48 to 50, the numbers 50, 60...140, 150, etc. indicate that the thickness of the light-transmitting medium pattern is 50 nm, 60 nm...140 nm, 150 nm, etc., respectively.

[0318] As shown in Figures 48 to 50, when the thickness of the transparent dielectric pattern is between 50nm and 150nm, the transmittance, reflectivity, and absorptivity of the metal wire grid are all linearly related to the thickness of the transparent dielectric pattern. Except for cases where the thickness of the transparent dielectric pattern is 50nm and 60nm, the absorptivity of the metal wire grid is around 0.15.

[0319] Figure 51 shows that the thickness of the metal wire grid's transparent dielectric layer significantly affects its transmittance. When the transparent dielectric layer is 70 nm thick, the wire grid's transmittance reaches a maximum of approximately 0.82, while its reflectivity reaches a minimum of approximately 0.03. When the thickness of the transparent dielectric layer exceeds 70 nm, the wire grid's absorptivity remains relatively constant, remaining around 0.15.

[0320] When the thickness of the light-transmitting dielectric layer of the metal wire grid is less than 140 nm, the polarization degree of the light emitted by the metal wire grid can reach above 0.99. Therefore, when the light-emitting device 40 emits blue light, setting the thickness of the light-transmitting dielectric pattern 4302 in the range of 60 nm to 80 nm can make the metal wire grid have higher transmittance and lower absorptivity, while also achieving a higher polarization degree, thereby improving the light extraction efficiency of the blue light emitted by the light-emitting device and reducing the light loss of the blue light of the light-emitting device.

[0321] In some other examples, when the light emitting device 40 emits blue light, the size of the light-transmitting medium pattern 4302 in the second direction Y ranges from 50 nm to 70 nm.

[0322] For example, when the light emitting device 40 emits blue light, the size of the light-transmitting medium pattern 4302 in the second direction Y may range from 50 nm to 60 nm or from 60 nm to 70 nm.

[0323] For example, when the light emitting device 40 emits blue light, the size of the light-transmitting medium pattern 4302 in the second direction Y may be 50 nm, 54 nm, 60 nm, 66 nm, or 70 nm.

[0324] By adopting the above arrangement, the light-transmitting medium pattern can be matched with the corresponding second metal pattern, thereby making the transmittance of the metal wire grid higher, and thus making the light extraction efficiency of the blue light emitted by the light-emitting device higher.

[0325] In some other examples, when the light-emitting device 40 emits blue light, the repetition period of the second metal pattern 4303 in the second direction Y is less than or equal to 140 nm, and the thickness range of the transparent medium pattern 4302 is 60 nm to 80 nm, and the size range of the transparent medium pattern 4302 in the second direction Y is 50 nm to 70 nm.

[0326] For example, when the light emitting device 40 emits blue light, the repetition period of the second metal pattern 4303 in the second direction Y is 120 nm, the thickness of the transparent medium pattern 4302 is 60 nm, and the size of the transparent medium pattern 4302 in the second direction Y is 60 nm.

[0327] In some embodiments, when the light-emitting device 40 emits green or red light, the repetition period of the second metal pattern 4303 in the second direction Y is less than or equal to 240 nm. Furthermore, the thickness of the light-transmitting medium pattern 4302 ranges from 70 nm to 90 nm. Furthermore, the dimension of the light-transmitting medium pattern 4302 in the second direction Y ranges from 110 nm to 130 nm.

[0328] For example, the wavelength range of the red light may be 620 nm to 640 nm, and the wavelength range of the green light may be 520 nm to 540 nm.

[0329] In some examples, when the light-emitting device 40 emits green light, the repetition period of the second metal pattern 4303 in the second direction Y is less than or equal to 240 nm. Furthermore, the thickness of the light-transmitting dielectric pattern 4302 ranges from 70 nm to 90 nm. Furthermore, the dimension of the light-transmitting dielectric pattern 4302 in the second direction Y ranges from 110 nm to 130 nm.

[0330] Exemplarily, when the light emitting device 40 emits green light, a repetition period of the second metal pattern 4303 in the second direction Y is less than or equal to 240 nm.

[0331] For example, in the case where the light emitting device 40 emits green light, the repetition period of the second metal pattern 4303 in the second direction Y is 240 nm or 200 nm.

[0332] For example, when the light emitting device 40 emits green light, the thickness of the light-transmitting medium pattern 4302 ranges from 70 nm to 90 nm.

[0333] For example, when the light emitting device 40 emits green light, the thickness of the light-transmitting medium pattern 4302 may be in the range of 70 nm to 80 nm or 80 nm to 90 nm.

[0334] For example, when the light emitting device 40 emits green light, the thickness of the light-transmitting medium pattern 4302 is 70 nm, 75 nm, 80 nm, 86 nm, or 90 nm.

[0335] For example, when the light emitting device 40 emits green light, the size of the light-transmitting medium pattern 4302 in the second direction Y ranges from 110 nm to 130 nm.

[0336] For example, when the light emitting device 40 emits green light, the size of the light-transmitting medium pattern 4302 in the second direction Y ranges from 110 nm to 120 nm or from 120 nm to 130 nm.

[0337] For example, when the light emitting device 40 emits green light, the size of the light-transmitting medium pattern 4302 in the second direction Y may be 110 nm, 115 nm, 120 nm, 126 nm, or 130 nm.

[0338] For example, when the light-emitting device 40 emits green light, the repetition period of the second metal pattern 4303 in the second direction Y is less than or equal to 240 nm. Furthermore, the thickness of the light-transmitting dielectric pattern 4302 ranges from 70 nm to 90 nm. Furthermore, the dimension of the light-transmitting dielectric pattern 4302 in the second direction Y ranges from 110 nm to 130 nm.

[0339] By adopting the above-mentioned setting method, when the light-emitting device emits green light, the transmittance of the metal wire grid in the light-emitting device to green light can be made higher, and the polarization degree of the green light emitted by the metal wire grid can be made higher, thereby improving the light-emitting efficiency and polarization degree of the light-emitting device emitting green light.

[0340] In some examples, when the light-emitting device 40 emits red light, the repetition period of the second metal pattern 4303 in the second direction Y is less than or equal to 240 nm. Furthermore, the thickness of the light-transmitting dielectric pattern 4302 ranges from 70 nm to 90 nm. Furthermore, the dimension of the light-transmitting dielectric pattern 4302 in the second direction Y ranges from 110 nm to 130 nm.

[0341] Exemplarily, when the light emitting device 40 emits red light, a repetition period of the second metal pattern 4303 in the second direction Y is less than or equal to 240 nm.

[0342] For example, when the light emitting device 40 emits red light, the sum of the size of the first metal pattern 4301 in the second direction Y and the size of the adjacent second metal pattern 4303 in the second direction Y is 240 nm or 200 nm.

[0343] For example, when the light emitting device 40 emits red light, the thickness of the light-transmitting medium pattern 4302 ranges from 70 nm to 90 nm.

[0344] For example, when the light emitting device 40 emits red light, the thickness of the light-transmitting medium pattern 4302 may be in the range of 70 nm to 80 nm or 80 nm to 90 nm.

[0345] For example, when the light emitting device 40 emits red light, the thickness of the light-transmitting medium pattern 4302 is 70 nm, 75 nm, 80 nm, 86 nm, or 90 nm.

[0346] For example, when the light emitting device 40 emits red light, the size of the light-transmitting medium pattern 4302 in the second direction Y ranges from 110 nm to 130 nm.

[0347] For example, when the light emitting device 40 emits red light, the size of the light-transmitting medium pattern 4302 in the second direction Y ranges from 110 nm to 120 nm or from 120 nm to 130 nm.

[0348] For example, when the light emitting device 40 emits red light, the size of the light-transmitting medium pattern 4302 in the second direction Y may be 110 nm, 115 nm, 120 nm, 126 nm, or 130 nm.

[0349] For example, when the light-emitting device 40 emits red light, the repetition period of the second metal pattern 4303 in the second direction Y is less than or equal to 240 nm. Furthermore, the thickness of the light-transmitting medium pattern 4302 ranges from 70 nm to 90 nm. Furthermore, the dimension of the light-transmitting medium pattern 4302 in the second direction Y ranges from 110 nm to 130 nm.

[0350] By adopting the above-mentioned setting method, when the light-emitting device emits red light, the transmittance of the metal wire grid in the light-emitting device to red light can be made higher, and the polarization degree of the red light emitted by the metal wire grid can be made higher, thereby improving the light-emitting efficiency and polarization degree of the light-emitting device emitting red light.

[0351] In some embodiments, as shown in FIG. 8 , the light emitting device 40 further includes a buffer layer 44 located between the epitaxial structure 42 and the at least one metal wire grid 43 .

[0352] Exemplarily, when the light emitting device 40 includes a plurality of metal wire grids 43 , the buffer layer 44 is located between the metal wire grid 43 closest to the epitaxial structure 42 and the epitaxial structure 42 .

[0353] The presence of the buffer layer 44 reduces the difference between the refractive index of the contacting or adjacent first semiconductor layer 421 and the refractive index of the buffer layer 44, and reduces the difference between the refractive index of the contacting or adjacent buffer layer 44 and the refractive index of the metal wire grid 43, thereby improving the light extraction efficiency of the light-emitting device 40. This can avoid a large difference between the refractive index of the metal wire grid 43 and the refractive index of the first semiconductor layer 421 in the epitaxial structure, and avoid causing large light loss due to the large difference in refractive indices between the two when light is incident from the metal wire grid 43 to the epitaxial structure 42 or when the epitaxial structure is incident on the metal wire grid 43.

[0354] For example, the material of the buffer layer may be silicon dioxide, silicon nitride (SiNx), photoresist (PR for short), PMMA, or the like.

[0355] The inventors simulated the cases of setting no buffer layer and setting a buffer layer in the light emitting device 40. The wavelength of the light emitted by the epitaxial structure was 460 nm. The transmittance and polarization degree of the metal wire grid 43 were calculated and plotted as shown in FIG52.

[0356] As shown in FIG52 , the light-emitting device 40 with a buffer layer exhibits higher transmittance and lower absorptivity than the light-emitting device 40 without a buffer layer. When the thickness of the light-transmitting dielectric pattern is 70 nm, the transmittance of the metal wire grid without a buffer layer differs by approximately 10% from that of the metal wire grid with a buffer layer.

[0357] Therefore, providing the buffer layer 44 in the light emitting device 40 can improve the transmittance of the metal wire grid 43 and further improve the light extraction efficiency of the light emitting device.

[0358] In some embodiments, the buffer layer 44 has a thickness ranging from 60 nm to 80 nm.

[0359] In some examples, the buffer layer 44 may have a thickness ranging from 60 nm to 70 nm or from 70 nm to 80 nm.

[0360] For example, the buffer layer 44 may have a thickness in the range of 60 nm, 67 nm, 70 nm, 76 nm, or 80 nm.

[0361] The inventors simulated the light emitting device 40 with buffer layers of different thicknesses, calculated the transmittance and absorptivity of the metal wire grid 43 , and plotted them as shown in FIG53 to FIG55 .

[0362] In Figure 53, T_H=0 represents the transmittance of the metal wire grid when the thickness of the buffer layer is 0 nm, T_H=20 represents the transmittance of the metal wire grid when the thickness of the buffer layer is 20 nm... T_H=200 represents the transmittance of the metal wire grid when the thickness of the buffer layer is 200 nm.

[0363] In Figure 54, Abs_H=0 represents the absorption rate of the metal wire grid when the thickness of the buffer layer is 0 nm, Abs_H=20 represents the absorption rate of the metal wire grid when the thickness of the buffer layer is 20 nm... Abs_H=200 represents the absorption rate of the metal wire grid when the thickness of the buffer layer is 200 nm.

[0364] In Figure 55, R_H=0 represents the reflectivity of the metal wire grid when the thickness of the buffer layer is 0 nm, R_H=20 represents the reflectivity of the metal wire grid when the thickness of the buffer layer is 20 nm...R_H=200 represents the reflectivity of the metal wire grid when the thickness of the buffer layer is 200 nm.

[0365] 53 to 55 , it can be seen that the wavelength of the light emitting device 40 has little significant effect on the transmittance of the metal wire grid. When the buffer layer thickness ranges from 60 nm to 80 nm, the transmittance of the metal wire grid reaches a maximum value and the absorptivity reaches a minimum value.

[0366] In addition, the inventors simulated the light emitted by the light emitting device 40 with a wavelength of 460nm and different buffer layer thicknesses, and calculated the transmittance, reflectivity, and reflectivity of the metal wire grid, resulting in Figure 56. As shown in Figure 56, when the buffer layer thickness ranges from 60nm to 80nm, the transmittance of the metal wire grid is 75%, the absorptivity is 8%, and the reflectivity is 18%, thereby achieving higher luminous efficiency of the light emitting device.

[0367] In some embodiments, the refractive index of the buffer layer 44 ranges from 1.4 to 1.5.

[0368] For example, the refractive index of the buffer layer 44 may be 1.40, 1.43, 1.45, 1.48, or 1.50.

[0369] The inventors simulated the light emitting device 40 with buffer layers having different refractive indices, calculated the transmittance and absorptivity of the metal wire grid 43 , and plotted them as shown in FIG57 to FIG60 .

[0370] In Figure 57, T_n=1.4 represents the transmittance of the metal wire grid when the refractive index of the buffer layer is 1.4, T_n=1.5 represents the transmittance of the metal wire grid when the refractive index of the buffer layer is 1.5... T_n=2.4 represents the transmittance of the metal wire grid when the refractive index of the buffer layer is 2.4.

[0371] In Figure 58, Abs_n=1.4 represents the absorption rate of the metal wire grid when the refractive index of the buffer layer is 1.4, Abs_n=1.5 represents the absorption rate of the metal wire grid when the refractive index of the buffer layer is 1.5... Abs_n=2.4 represents the absorption rate of the metal wire grid when the refractive index of the buffer layer is 2.4.

[0372] In Figure 59, R_n=1.4 represents the reflectivity of the metal wire grid when the refractive index of the buffer layer is 1.4, R_n=1.5 represents the reflectivity of the metal wire grid when the refractive index of the buffer layer is 1.5...R_n=2.4 represents the reflectivity of the metal wire grid when the refractive index of the buffer layer is 2.4.

[0373] 57 to 59 , it can be seen that the smaller the refractive index of the buffer layer 44 is, the greater the transmittance of the metal wire grid is, the smaller the absorptivity is, and the smaller the reflectivity is.

[0374] In addition, the wavelength is set to 460nm, the refractive index range of the buffer layer 44 is 1.4 to 2.4, and the transmittance, absorptivity and reflectivity of the metal wire grid are simulated and calculated to obtain Figure 60. When the refractive index of the buffer layer is small, the greater the transmittance of the metal wire grid, the smaller the absorptivity. The change trend between the transmittance of the metal wire grid and the refractive index of the buffer layer is not completely a linear relationship. As the refractive index of the buffer layer continues to decrease, the transmittance of the metal wire grid continues to increase. Therefore, setting the refractive index of the buffer layer in the range of 1.4 to 1.5 can make the transmittance of the metal wire grid higher.

[0375] For example, the material of the buffer layer may be magnesium fluoride (MgF) or polymethyl methacrylate (PMMA), etc. The refractive index of PMMA is 1.48.

[0376] It is understood that during the fabrication of the light-emitting device, the epitaxial structure and the metal wire grid can be prepared separately, and then the metal wire grid and the epitaxial structure can be bonded together. For example, an optical clear adhesive (OCA) with a refractive index of 1.5 can be selected to bond the metal wire grid and the epitaxial structure. During the fabrication of the metal wire grid, a substrate is required. For example, the substrate can be silicon dioxide (SiO2) or glass. Then, a first metal layer, a light-transmitting dielectric layer, and a second metal layer are formed on the substrate.

[0377] The inventors simulated the case where the metal wire grid includes the above-mentioned substrate (taking the substrate material as glass as an example), calculated the transmittance and polarization degree of the metal wire grid, and plotted it to obtain Figure 61.

[0378] As shown in Figure 61, when the metal wire grid includes a substrate and the wavelength of light incident on the metal wire grid is 460nm, the transmittance of the metal wire grid decreases slightly, by approximately 0.1 (compared to Figure 60 in the text), while the degree of polarization remains essentially unchanged, remaining at approximately 0.9979. Therefore, to reduce the influence of the substrate on the transmittance of the metal wire grid, the metal wire grid can be directly integrated into the epitaxial structure during the preparation of the light-emitting device, thereby avoiding the loss of transmittance of the metal wire grid caused by the substrate, thereby improving the light extraction efficiency of the light-emitting device.

[0379] The inventors simulated a metal wire grid constructed using the optimized structural parameters of the above-mentioned multiple embodiments, and obtained the transmittance, reflectivity, absorptivity and polarization degree of the metal wire grid through simulation calculation, and plotted them as Figures 62 and 63. Specifically, the wavelength range of the light incident on the metal wire grid is set to be 450nm to 470nm, the first metal pattern and the second metal pattern of the metal wire grid are made of the same material, both aluminum, the repetition period of the second metal pattern of the metal wire grid is 120nm, the size of the first metal pattern (or the second metal pattern) in the second direction is 60nm, the thickness of the first metal pattern is 60nm, the refractive index of the transparent medium pattern is 1.4, the thickness of the transparent medium pattern is 70nm, the size of the transparent medium pattern in the second direction is 60nm, the refractive index of the buffer layer is 1.4, the thickness of the buffer layer is 70nm, and the metal wire grid is formed directly on the epitaxial structure.

[0380] In Figure 62, T_TM represents the transmittance of the metal wire grid TM light, T_TE represents the transmittance of the metal wire grid TE light, R_TM represents the reflectivity of the metal wire grid TM light, R_TE represents the reflectivity of the metal wire grid TE light, Abs_TM represents the absorptivity of the metal wire grid TM light, and Abs_TE represents the absorptivity of the metal wire grid TE light.

[0381] As shown in Figures 62 and 63, the polarization degree of the metal wire grid is greater than or equal to 0.999, the transmittance of the TM light of the metal wire grid is as high as 0.825, the reflectivity of the TM light of the metal wire grid is almost 0, the absorptivity of the TM light of the metal wire grid is 0.16, the transmittance of the TE light of the metal wire grid is almost 0, the reflectivity of the TE light of the metal wire grid is approximately 0.82, and the absorptivity of the TE light of the metal wire grid is 0.18. Therefore, the above-mentioned configuration can greatly improve the light extraction efficiency of the light-emitting device and reduce the light loss of the light-emitting device.

[0382] It should be noted that the above embodiment is introduced based on the example of the light-emitting device 40 emitting blue light. When the light-emitting device 40 emits red light or green light, the structural parameters of the metal wire grid 43 can be set as follows: the first metal pattern and the second metal pattern of the metal wire grid 43 are made of the same material, both aluminum, the repetition period of the second metal pattern of the metal wire grid 43 is 240nm, the size of the first metal pattern (or the second metal pattern) in the second direction is 120nm, the thickness of the first metal pattern is 60nm, the refractive index of the transparent medium pattern is 1.4, the thickness of the transparent medium pattern is 80nm, the size of the transparent medium pattern in the second direction is 120nm, the refractive index of the buffer layer is 1.4, and the thickness of the buffer layer is 70nm. In this way, the light extraction efficiency of the light-emitting device 40 emitting red light or blue light can be greatly improved, the polarization degree of the light extracted by the light-emitting device 40 can be improved, the light consumption of the light-emitting device 40 can be reduced, and the power consumption of the backlight module or display device can be reduced.

[0383] It is understandable that there are various types of the first light conversion layer 41 , which can be selected and configured as needed, and the present disclosure does not impose any limitation thereto.

[0384] In some embodiments, as shown in FIG. 9 , the first light conversion layer 41 includes a specular reflection layer 411 .

[0385] For example, the surface of the mirror reflection layer 411 is relatively flat.

[0386] For example, the material of the mirror reflective layer 411 can be a metal or a metal alloy. For example, the material of the mirror reflective layer 411 can include metallic silver with a mass percentage of greater than or equal to 90%. This can reduce the absorption of light by the mirror reflective layer 411, thereby reducing the light loss of the light-emitting device 40. Furthermore, light absorption losses can also be reduced by reducing the thickness of other film layers (such as the buffer layer) in the light-emitting device 40.

[0387] In some examples, the mirror reflective layer 411 is configured to reflect a portion of the light incident on the mirror reflective layer 411 .

[0388] Exemplarily, most of the light emitted by the epitaxial structure is incident on the metal wire grid 43, and is reflected, absorbed or transmitted by the metal wire grid 43. Among them, most of the TM light is emitted through the metal wire grid 43, and most of the TE light is reflected by the metal wire grid 43 to the mirror reflection layer 411. This part of the TE light is incident on the epitaxial structure, and is incident on the mirror reflection layer 411 through the epitaxial structure. After being reflected on the mirror reflection layer 411, it is incident on the epitaxial structure again, and is incident on the metal wire grid 43 through the epitaxial structure. In the process of the TE light passing through the epitaxial structure twice, at least a portion of the TE light is depolarized by the epitaxial structure, changing the polarization direction, so that at least a portion of the TE light is converted into circularly polarized light and is incident on the metal wire grid. In the circularly polarized light, the light perpendicular to the transmission axis direction of the metal wire grid 43 can be emitted from the metal wire grid 43. Among the above-mentioned circularly polarized light, the light parallel to the transmission axis direction of the metal wire grid 43 will be reflected by the metal wire grid 43, and then enter the epitaxial structure again, and after being depolarized in the epitaxial structure, enter the mirror reflection layer 411, and then be reflected by the mirror reflection layer 411 to the epitaxial structure, and then be depolarized in the epitaxial structure and enter the metal wire grid again, and the above process will be repeated continuously.

[0389] By adopting the above-mentioned setting method, the mirror reflection layer 411 is used to reflect the light reflected by the metal wire grid 43 and then deflected by the epitaxial structure to the metal wire grid again, and then emitted after being screened by the metal wire grid, thereby avoiding the loss of this part of the light, thereby reducing the loss rate of the light emitted by the epitaxial structure 42, and avoiding further improving the luminous efficiency of the light-emitting device 40.

[0390] It is understandable that the epitaxial structure has a certain depolarization effect on light and also has a certain absorption effect on light. Therefore, the thickness of the epitaxial structure can be reduced to reduce the absorption loss of light by the epitaxial structure.

[0391] In some examples, the reflectivity of the specular reflective layer 411 is greater than or equal to 80%.

[0392] For example, the reflectivity of the mirror reflection layer 411 is 80%, 85%, 90%, 96% or 100%.

[0393] By setting the reflectivity of the mirror reflection layer 411 within the above range, the utilization rate of the light emitted by the epitaxial structure can be improved, the loss of the light can be reduced, and the luminous efficiency of the light-emitting device can be improved.

[0394] In some embodiments, as shown in FIG. 9 , the first light conversion layer 41 includes a scattering reflective layer 412 .

[0395] Exemplarily, the surface of the scattering reflection layer 412 has a certain degree of roughness.

[0396] Exemplarily, the material of the scattering reflective layer 412 may be a metal or a metal alloy. For example, the material of the scattering reflective layer 412 may include metallic silver having a mass percentage of greater than or equal to 90%. This can reduce the absorption of light by the scattering reflective layer 412, thereby reducing light loss of the light-emitting device.

[0397] In some examples, the scattering reflective layer 412 is configured to scatter or reflect a portion of the light incident on the scattering reflective layer 412 and convert at least a portion of the light scattered or reflected by the scattering reflective layer 412 into natural light.

[0398] It can be understood that most of the light reflected by the metal wire grid to the scattering reflection layer 412 is TE light. The TE light is reflected or scattered by the scattering reflection layer 412 and converted into natural light by the scattering reflection layer 412. The natural light can then be incident on the metal wire grid again and then filtered by the metal wire grid, thereby reducing the loss rate of light emitted by the epitaxial structure and avoiding thereby improving the luminous efficiency of the light-emitting device.

[0399] For example, the light incident on the scattering reflection layer 412 and then emitted from the scattering reflection layer 412 satisfies Lambert's cosine law I=I0×cos N(θ). Here, I is the intensity of the outgoing light, I0 refers to the intensity of the light emitted from the normal direction of the scattering reflective layer, θ is the reflection angle or scattering angle of the light reflected from the scattering reflective layer, I is the intensity of the light with a reflection angle or scattering angle of θ, and N is the roughness of the scattering reflective layer 412. The smaller N, the smaller the roughness of the scattering reflective layer 412. When N is small, the scattering reflective layer 412 almost entirely reflects the incident light, and the scattering effect is weak.

[0400] Exemplarily, the roughness of the scattering reflection layer 412 is greater than or equal to 2 μm.

[0401] For example, the roughness of the scattering reflection layer 412 is 2.0 μm, 2.2 μm, 2.6 μm, 3.0 μm, or 3.2 μm.

[0402] It is understood that the scattering properties of the scattering reflective layer 412 are related to its surface roughness and the angle of incidence of the light. When incident on the scattering reflective layer 412 at medium to large angles, the light exiting the scattering reflective layer 412 no longer strictly adheres to Lambert's cosine law. In practice, when the roughness N of the scattering reflective layer 412 is less than 1 μm, the intensity of the light exiting the scattering reflective layer 412 is concentrated near the angle of specular reflection, indicating that the scattering reflective layer 412 has a moderate scattering effect on the incident light. When the roughness N of the scattering reflective layer 412 is greater than or equal to 2 μm, the intensity of the light exiting the scattering reflective layer 412 conforms to Lambert's cosine law. In other words, the intensity of the light exiting the scattering reflective layer 412 is similar at all angles. Therefore, by setting the roughness of the scattering reflection layer 412 within the above-mentioned range, the light intensity of most of the light emitted from the scattering reflection layer 412 can be made to have little difference in the scattering intensity at various angles, and the light can also be considered as natural light. When the natural light is incident on the metal wire grid, it can be filtered by the metal wire grid, so that the TM light is emitted from the metal wire grid, thereby improving the light extraction efficiency of the light-emitting device.

[0403] In some embodiments, as shown in FIG. 9 , the first light conversion layer 41 includes a phase conversion layer 413 .

[0404] For example, the phase conversion layer 413 can perform a phase conversion on light incident on its surface. The phase of the light incident on the surface of the phase conversion layer 413 is different from the phase of the light emitted from the surface after the phase conversion effect of the phase conversion layer 413. The phase difference can be (2n-1)π, (2n-1)×π / 2, etc., where n is a positive integer.

[0405] For example, when n is 1 and the phase conversion layer 413 can perform a π-phase conversion on the light incident on its surface, the phase conversion layer 413 can convert the TE light incident on its surface into TM light before emitting it. As a result, the TM light can be emitted from the metal wire grid, thereby improving the light extraction efficiency of the light-emitting device.

[0406] In some examples, as shown in Figures 64 and 65 , the phase conversion layer 413 includes a plurality of nano-pillar structures 414. The plurality of nano-pillar structures 414 are arranged in an array.

[0407] For example, the material of the nanorod structure 414 may be silicon nitride.

[0408] For example, when the material of the nanocolumn structure 414 is silicon nitride, the refractive index of the nanocolumn structure is about 2.0, thereby making the preparation process of the nanocolumn structure compatible with the preparation process of the light-emitting device, thereby reducing the difficulty of preparing the light-emitting device.

[0409] For example, when the material of the nanorod structure 414 is silicon nitride, the extinction coefficient of the nanorod structure is close to 0. Therefore, the absorption of light by the nanorod structure can be avoided as much as possible, thereby reducing the light loss of the light emitting device.

[0410] For example, the plurality of nanorod structures 414 can perform a phase conversion effect on light incident on the surface thereof.

[0411] Exemplarily, the light emitting device 40 further includes a first substrate 48 , which is located on a side of the phase conversion layer 413 away from the epitaxial structure.

[0412] For example, the first substrate 48 has a substantially flat surface, and the plurality of nanorod structures 414 are located on the first substrate 48 .

[0413] In some other examples, as shown in FIG66 , the phase conversion layer 413 includes a plurality of through holes 415. The plurality of through holes 415 are periodically arranged.

[0414] For example, the orthographic projection shape of the plurality of through holes on the first substrate is a rectangle.

[0415] In some other examples, the first substrate 48 in the light-emitting device includes a plurality of grooves, which are arranged periodically, and the first substrate is reused as the phase conversion layer 413 .

[0416] For example, the orthographic projection of the plurality of grooves on the plane where the first substrate is located is a rectangle.

[0417] In yet other examples, the phase conversion layer includes a plurality of nanorod structures and a plurality of through holes.

[0418] Exemplarily, the plurality of through holes and the plurality of nano-pillar structures are arranged periodically.

[0419] For example, the shape of the orthographic projection of the through hole on the first substrate is substantially the same as the shape of the orthographic projection of the nanorod structure on the first substrate.

[0420] In some other examples, the phase conversion layer is a wire grid structure.

[0421] It is understood that in the case where the phase conversion layer includes multiple nanopillar structures, the case where the phase conversion layer includes multiple through holes, and the case where the phase conversion layer includes multiple grooves, the arrangement period and structural parameters of the multiple nanopillar structures are substantially the same as the arrangement period and structural parameters of the multiple through holes, and the arrangement period and structural parameters of the multiple grooves. When light is incident on these nanopillars, through holes, or grooves, phase conversion can occur. For ease of explanation, the following description uses the example of a phase conversion layer including multiple nanopillar structures.

[0422] Specifically, when light is incident on the nanopillar structure, the phase difference before and after phase conversion can be 0 to 2π. Within the phase difference of 0 to 2π, there are eight phase differences, namely π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4, and 2π. For example, by adjusting parameters such as the arrangement period and structural parameters of the nanopillar structure, the incident light can be precisely converted between the eight phase differences. Furthermore, the different arrangement periods and structural parameters of the multiple nanopillar structures 414 will also affect the phase conversion efficiency of the phase conversion layer 413. Furthermore, the phase conversion efficiency is also related to the wavelength of the light incident on the multiple nanopillar structures 414. Therefore, for light-emitting devices emitting light of different wavelengths, the arrangement period and structural parameters of the nanopillar structures in the phase conversion layer 413 provided therein are also different. For example, as shown in FIG64 , the nanopillar structure 414 can be in the shape of a rectangular parallelepiped. The arrangement period of the nanopillar structures 414 includes a first period P1 and a second period P2. The first period P1 is the recurring period of the long side L in a top view of the cuboid, and the second period P2 is the recurring period of the short side W in a top view of the cuboid. Structural parameters of the nanopillar structures 414 include the long side L, the short side W, and the height H of the nanopillar structures.

[0423] The nanorod structure is described below by taking the case where the phase conversion layer 413 can convert the phase of light incident on its surface by (2n-1)×π / 2 as an example.

[0424] For example, in the light-emitting device, the first period P1 and the second period P2 of the plurality of nanorod structures 414 are equal, thereby simplifying the manufacturing process of the phase conversion layer and the light-emitting device.

[0425] For example, when the light-emitting device emits red light (e.g., the wavelength of the red light is 620 nm), the first period P1 and the second period P2 are both 300 nm, the height of the nanopillar structure is 700 nm, the ratio of the height H of the nanopillar structure to the short side dimension W of the nanopillar structure is greater than or equal to 5:1, the ratio of the long side dimension L to the short side dimension W of the nanopillar structure is 1, and the short side dimension W of the nanopillar structure is 120 nm. In this case, the phase shift layer can perform a π / 2 phase shift on most red light incident on its surface. If the short side dimension of the nanopillar structure is set to 60 nm among the above structural parameters, while the other structural parameters remain the same, the phase shift layer can perform a 3π / 2 phase shift on blue light incident on its surface.

[0426] In this way, the efficiency of the nanocolumn structure in phase conversion of the red light incident thereon can be improved, so that most of the red light incident on the phase conversion layer can undergo phase conversion. For example, most of the red light incident on the nanocolumn structure is reflected by the metal wire grid to the phase conversion layer. This part of the red light is TE light. After passing through the phase conversion layer, it undergoes a π / 2 (n is 1 here) phase conversion, and then is emitted to the metal wire grid. After being reflected by the metal wire grid, it is incident on the phase conversion layer again and undergoes a π / 2 phase conversion again. That is, after two phase conversions, most of the TE light is converted into TM light, and then this part of the TM light can be incident on the metal wire grid again, so that it can be emitted through the metal wire grid, thereby improving the light output efficiency of the light-emitting device emitting red light.

[0427] For another example, when the light-emitting device emits blue light (e.g., the wavelength of the blue light is 450nm), the first period P1 and the second period P2 are both 225nm, the height of the nanopillar structure is 700nm, the ratio of the height of the nanopillar structure to the short side dimension W of the nanopillar structure is greater than or equal to 5:1, the ratio of the long side dimension L to the short side dimension W of the nanopillar structure is 1, and the short side dimension W of the nanopillar structure is 45nm. Then, the phase shift layer can perform a π / 2 phase shift on the blue light incident on its surface. If the short side dimension of the nanopillar structure in the above structural parameters is set to 80nm, while the other structural parameters remain the same, then the phase shift layer can perform a 3π / 2 phase shift on the blue light incident on its surface.

[0428] In this way, the efficiency of the nanocolumn structure in phase conversion of the blue light incident thereon can be improved, so that most of the light incident on the phase conversion layer can undergo phase conversion. For example, most of the blue light incident on the nanocolumn structure is reflected by the metal wire grid to the phase conversion layer. This part of the blue light is TE light. After passing through the phase conversion layer, it undergoes a π / 2 (n is 1 here) phase conversion, and then is emitted to the metal wire grid. After being reflected by the metal wire grid, it is incident on the phase conversion layer again and undergoes a π / 2 phase conversion again. That is, after two phase conversions, most of the TE light is converted into TM light, and then this part of the TM light can be incident on the metal wire grid again, so that it can be emitted through the metal wire grid, thereby improving the light output efficiency of the light-emitting device emitting blue light.

[0429] For another example, when the light-emitting device emits green light (e.g., the wavelength of the green light is 532 nm), the first period P1 and the second period P2 are both 250 nm, the height of the nanopillar structure is 700 nm, the ratio of the height of the nanopillar structure to the short side dimension W of the nanopillar structure is greater than or equal to 5:1, the ratio of the long side dimension L to the short side dimension W of the nanopillar structure is 1, and the short side dimension W of the nanopillar structure is 80 nm. In this case, the phase shift layer can perform a π phase shift on green light incident on its surface. If the short side dimension of the nanopillar structure is set to 115 nm among the above structural parameters, while the other structural parameters remain the same, the phase shift layer can perform a 3π phase shift on green light incident on its surface.

[0430] In this way, the efficiency of the nanocolumn structure in phase conversion of the green light incident thereon can be improved, so that most of the light incident on the phase conversion layer can undergo phase conversion. For example, most of the green light incident on the nanocolumn structure is reflected by the metal wire grid to the phase conversion layer. This part of the green light is TE light. After passing through the phase conversion layer, it undergoes a π / 2 (n is 1 here) phase conversion, and then is emitted to the metal wire grid. After being reflected by the metal wire grid, it is incident on the phase conversion layer again and undergoes a π / 2 phase conversion again. That is, after two phase conversions, most of the TE light is converted into TM light, and then this part of the TM light can be incident on the metal wire grid again, so that it can be emitted through the metal wire grid, thereby improving the light output efficiency of the light-emitting device emitting green light.

[0431] In one implementation, a quarter-wave plate replaces the phase conversion layer in the above embodiment. The quarter-wave plate can also phase-convert light incident on its surface. However, its transmittance is approximately 50% to 60%, and its polarization conversion efficiency is approximately 25% to 30%, which is relatively low. The quarter-wave plate has a complex structure, and its fabrication process is incompatible with existing light-emitting device fabrication processes, making it difficult to directly integrate it into an epitaxial structure. Furthermore, its thickness is relatively large, hindering the design of thin and lightweight display devices.

[0432] Some embodiments of the present disclosure utilize the above-mentioned phase conversion layer including multiple nanocolumn structures. The transmittance of the phase conversion layer is as high as 85%, and the polarization conversion rate is about 42.5%. It can be adjusted accordingly according to the wavelength of the light whose phase needs to be converted, thereby obtaining a higher polarization conversion efficiency. The thickness of the phase conversion layer is small, and it can be made into an ultra-thin nanometer-scale size, which is conducive to the lightweight design of light-emitting devices and display devices. In addition, the preparation method of the phase conversion layer is compatible with the preparation method of other film layers of the light-emitting device, so that the phase conversion layer can be prepared on the epitaxial structure, thereby simplifying the preparation process of the light-emitting device. The phase conversion layer can perform phase conversion on light within the wavelength range (380nm~780nm) of the entire white light spectrum, and can accurately control the phase change of the incident light, such as a phase change value of nπ / 2.

[0433] The nanorod structure is described below by taking the case where the phase conversion layer 413 can convert the light incident on its surface into a (2n-1)π phase as an example.

[0434] For example, in the light-emitting device, the first period P1 and the second period P2 of the plurality of nanorod structures 414 are equal, thereby simplifying the manufacturing process of the phase conversion layer and the light-emitting device.

[0435] For example, when the light-emitting device emits red light (for example, the wavelength of the red light is 620 nm), the first period P1 and the second period P2 are both 300 nm, the height of the nanocolumn structure is 700 nm, the ratio of the height of the nanocolumn structure to the short side dimension W of the nanocolumn structure is greater than or equal to 5:1, the ratio of the long side dimension L to the short side dimension W of the nanocolumn structure is 1, and the short side dimension W of the nanocolumn structure is 140 nm, then, the phase conversion layer can convert the phase of most of the red light incident on its surface into (2n-1)π.

[0436] In this way, the efficiency of the nanocolumn structure in phase conversion of the red light incident thereon can be improved, so that most of the light incident on the phase conversion layer can undergo phase conversion. For example, most of the red light incident on the nanocolumn structure is reflected by the metal wire grid to the phase conversion layer. This part of the red light is TE light. After passing through the phase conversion layer and undergoing a (2n-1)π phase conversion, most of it is converted into TM light. This part of the TM light can then be incident on the metal wire grid again, so that it can be emitted through the metal wire grid, thereby improving the light output efficiency of the light-emitting device emitting red light.

[0437] For another example, when the light-emitting device emits blue light (for example, the wavelength of the blue light is 450 nm), the first period P1 and the second period P2 are both 225 nm, the height of the nanocolumn structure is 700 nm, the ratio of the height of the nanocolumn structure to the short side dimension W of the nanocolumn structure is greater than or equal to 5:1, the ratio of the long side dimension L to the short side dimension W of the nanocolumn structure is 1, and the short side dimension W of the nanocolumn structure is 65 nm, then, the phase conversion layer can perform (2n-1)π phase conversion on the blue light incident on its surface.

[0438] In this way, the efficiency of the nanocolumn structure in phase conversion of the blue light incident thereon can be improved, so that most of the light incident on the phase conversion layer can undergo phase conversion. For example, most of the blue light incident on the nanocolumn structure is reflected by the metal wire grid to the phase conversion layer. This part of the blue light is TE light. After passing through the phase conversion layer, it undergoes a (2n-1)π phase conversion and most of it is converted into TM light. This part of the TM light can then be incident on the metal wire grid again, so that it can be emitted through the metal wire grid, thereby improving the light output efficiency of the light-emitting device emitting blue light.

[0439] For another example, when the light-emitting device emits green light (for example, the wavelength of the green light is 532 nm), the first period P1 and the second period P2 are both 250 nm, the height of the nanocolumn structure is 700 nm, the ratio of the height of the nanocolumn structure to the short side dimension W of the nanocolumn structure is greater than or equal to 5:1, the ratio of the long side dimension L to the short side dimension W of the nanocolumn structure is 1, and the short side dimension W of the nanocolumn structure is 100 nm, then, the phase conversion layer can perform (2n-1)π phase conversion on the green light incident on its surface.

[0440] In this way, the efficiency of the nanocolumn structure in phase conversion of the green light incident thereon can be improved, so that most of the light incident on the phase conversion layer can undergo phase conversion. For example, most of the green light incident on the nanocolumn structure is reflected by the metal wire grid to the phase conversion layer. This part of the green light is TE light. After passing through the phase conversion layer and undergoing a (2n-1)π phase conversion, most of it is converted into TM light. This part of the TM light can then be incident on the metal wire grid again, so that it can be emitted through the metal wire grid, thereby improving the light output efficiency of the light-emitting device emitting green light.

[0441] It can be understood that when the wavelengths of the light emitted by the above-mentioned light-emitting devices are different, the height of the nanocolumn structure can be set to 700nm. This can improve the processing convenience and consistency of different light-emitting devices, and enable the nanocolumn structure to achieve more efficient phase deflection for white light in the wavelength range of 380nm to 680nm.

[0442] For example, the plurality of nanorod structures 414 may also be randomly arranged.

[0443] In some embodiments, as shown in FIG. 65 , the light-emitting device 40 further includes a first reflective layer 45 covering the top and side surfaces of each nanorod structure 414 .

[0444] Exemplarily, the first reflective layer 45 can reflect light incident on its surface to prevent the light from being consumed by passing through the first reflective layer 45 , thereby reducing light consumption of the light-emitting device.

[0445] Exemplarily, the material of the first reflective layer may be a metal material. For example, the metal material may be silver. Using silver as the material of the first reflective layer can achieve a reflectivity of the first reflective layer of approximately 86%. For another example, the metal material may be aluminum. Using aluminum as the material of the first reflective layer can achieve a reflectivity of the first reflective layer of approximately 80%.

[0446] For example, the first reflective layer 45 may also be located in a region between two adjacent nanorod structures 414 in the first substrate 48 .

[0447] Because the first reflective layer 45 covers the nanorod structure and there is a step between the nanorod structure and the first substrate 48, the overall profile of the first reflective layer 45 exhibits periodic undulations. As a result, light incident on the first reflective layer 45 undergoes phase shift and reflection due to the interaction between the nanorod structure and the first reflective layer 45, thereby reducing light loss in the light-emitting device and increasing the brightness of the light emitted by the device.

[0448] In some embodiments, as shown in FIG. 67 , the light emitting device 40 further includes a second light conversion layer 46 located between the epitaxial structure 42 and the at least one metal wire grid 43 .

[0449] Exemplarily, the second light conversion layer 46 is configured to reflect or transmit a portion of the light incident on the second light conversion layer 46 and change the polarization direction of at least a portion of the light emitted after passing through the second light conversion layer 46 .

[0450] For example, light incident on the second light conversion layer 46 may be reflected on the surface of the second light conversion layer 46 and emitted toward the first light conversion layer 41 , or pass through the second light conversion layer 46 and be emitted toward the metal wire grid 43 .

[0451] Exemplarily, the second light conversion layer 46 can depolarize light incident on its surface. For example, the light reflected by the metal wire grid 43 is mostly TE light. This TE light enters the second light conversion layer 46 and is depolarized by the second light conversion layer 46, thereby converting at least a portion of the TE light into natural light. This natural light then enters the metal wire grid 43, which transmits the TM light contained in the natural light. The natural light can also be reflected by the second light conversion layer 46 and then enter the first light conversion layer 41, where it is reflected and changes its polarization direction, thereby improving the efficiency of converting the TE light into TM light. This in turn increases the transmittance of the metal wire grid 43 and improves the light extraction efficiency of the light-emitting device 40.

[0452] In some examples, second light conversion layer 46 is further configured to change the color of a portion of the light incident on second light conversion layer 46 .

[0453] For example, the material of the second light conversion layer 46 may include a color conversion material or a fluorescent material, so as to change the color of the light incident on the second light conversion layer 46 .

[0454] This arrangement reduces the number of light oscillations between the metal wire grid 43 and the first light conversion layer 41, such as the epitaxial structure 42 and the buffer layer. This reduces light absorption losses during the oscillation process, significantly improving the light extraction efficiency of the light-emitting device 40. Furthermore, the second light conversion layer 46 has a strong depolarization effect, and when combined with the first light conversion layer 41, this further improves the depolarization efficiency, thereby increasing the light extraction efficiency of the light-emitting device 40.

[0455] In some embodiments, as shown in FIG8 , the light-emitting device 40 further includes a second reflective layer 47. The second reflective layer 47 surrounds at least the first light conversion layer 41 and the side surfaces of the epitaxial structure 42. The second reflective layer 47 is configured to reflect light incident on the second reflective layer 47 and direct the reflected light toward the light-emitting side of the light-emitting device 40.

[0456] For example, when the light emitting device 40 further includes a buffer layer 44 , the second reflective layer 47 surrounds the first light conversion layer 41 , the epitaxial structure 42 and the side surfaces of the buffer layer 44 .

[0457] It can be understood that the light emitted by a single light-emitting device is emitted from the six surfaces of the light-emitting device, and its light emission color spectrum distribution diagram is shown in Figure 68. The light emission color spectrum of multiple array-arranged light-emitting devices is shown in Figure 69. It can be seen from Figure 68 that light with different light intensities is emitted in the normal direction of the top surface of the light-emitting device and in the direction with an angle to the normal. And at a large angle (the large angle here means that the angle between the light emission direction and the normal and the plane where the first direction is located is greater than 45°, or the angle between the light emission direction and the normal and the plane where the second direction is located is greater than 45°), the light intensity of the emitted light is greater than the light intensity of the light emitted in the normal direction. It can be seen from Figures 68 and 69 that the light emission conditions of multiple light-emitting devices are similar to those of a single light-emitting device. A comparison diagram of the light emission conditions of multiple light-emitting devices and the light emission conditions of a single light-emitting device is shown in Figure 70.

[0458] Light emitted at large angles is mostly emitted from the side of the light-emitting device, while light emitted at small angles (the small angle here refers to the angle between the light emission direction and the normal line is less than or equal to 45°) is mostly emitted from the main light-emitting surface of the light-emitting device (the main light-emitting surface here refers to the top surface of the light-emitting device, which can be considered as the main light-emitting surface of the light-emitting device). The light emitted from the main light-emitting surface is emitted from the epitaxial structure and then filtered by the metal wire grid. The light emitted from the side is mostly emitted from the side of the epitaxial structure. If it is not processed and is emitted without being filtered by the metal wire grid, it will reduce the polarization degree of the light emitted by the light-emitting device, thereby reducing the contrast of the display device.

[0459] The embodiment of the present disclosure includes a second reflective layer 47 that reflects light emitted from the side of the epitaxial structure 42 and reflects it into the interior of the epitaxial structure 42, causing it to pass through the metal wire grid and then be emitted along the main light-emitting surface of the light-emitting device. This can improve the polarization of the light emitted by the light-emitting device and enhance the contrast of the display device. In addition, the above arrangement can also reduce crosstalk between light emitted by adjacent light-emitting devices, thereby improving the display effect of the display device.

[0460] In some embodiments, as shown in FIG. 9 , the light emitting device 40 further includes a first electrode 491 and a second electrode 492 .

[0461] For example, the first electrode 491 is electrically connected to the first semiconductor layer 421 and provides a first voltage signal to the first semiconductor layer 421. The second electrode 492 is electrically connected to the second semiconductor layer 423 and provides a second voltage signal to the second semiconductor layer 423.

[0462] In one implementation, as shown in FIG71 , the backlight module also includes optical film layers such as a diffusion layer, a quantum dot enhancement film (QDEF), and a filter layer. These optical film layers are doped with a small amount of scattering particles and have a certain degree of depolarization, which can depolarize single-polarized light. In this way, when the single-polarized light emitted by the light-emitting device passes through the above-mentioned diffuser, QDEF and other optical film layers and is incident on the display panel, it will be depolarized by the above-mentioned optical film layers, thereby reducing the polarization degree of the backlight provided by the backlight module.

[0463] The depolarization degree of the above-mentioned optical film layer can be obtained through testing and analysis. Specifically, as shown in Figure 72, a light source is provided to provide natural light, a first polarizer and a second polarizer are respectively provided on both sides of the optical film layer to be tested, and a receiver is provided to detect the received light. The transmission axes of the first polarizer and the second polarizer are set perpendicular to each other. Natural light passes through the first polarizer and becomes single polarized light. Under the depolarization effect of the optical film layer to be tested, the above single polarized light will be depolarized, and then part of the light will pass through the second polarizer and be received by the receiver. The depolarization degree of the optical film to be tested can be obtained by calculating the ratio of the light intensity received by the receiver to the above single polarized light.

[0464] Specifically, the depolarization effect and transmittance of each optical film layer are shown in Figure 73.

[0465] As shown in Figure 73, QDEF can depolarize almost all single-polarized light, converting it from single-polarized light into natural light. Therefore, in a backlight module providing single-polarized backlight, a film layer with a high depolarization degree, such as QDEF, can be omitted. The sum of the depolarization degrees of diffusion layers 1 and 2 is approximately 24%. This means that after single-polarized light passes through two diffusion layers, approximately half of the light is depolarized into natural light. Therefore, it is best not to include a diffusion layer in a backlight module providing single-polarized backlight. The depolarization degree of the two-layer brightness enhancement film is 18%. Therefore, in a backlight module providing single-polarized backlight, the provision of the above-mentioned optical film layer will reduce the polarization degree of the backlight provided by the backlight module.

[0466] As shown in FIG. 74 , a backlight module 20 provided by some of the above embodiments of the present disclosure further includes: at least one light-uniforming layer 70 located on the plurality of light-emitting devices 40 .

[0467] For example, the plurality of light emitting devices 40 may include a red light emitting device, a blue light emitting device, a green light emitting device, and the like.

[0468] For example, at least one red light-emitting device, at least one blue light-emitting device, and at least one green light-emitting device constitute a light-emitting device group.

[0469] For example, the light emitting devices in a light emitting device group may be arranged in a triangle, a square, or a hexagonal arrangement, so that the red light, the green light, and the blue light emitted by the light emitting device group are mixed to produce white light.

[0470] For example, since the electro-optical conversion efficiency of the epitaxial structure that emits red light is low and the cost is high, a red light-emitting device can be formed by setting a color conversion layer on the epitaxial structure that emits green or blue light. The blue or green light emitted by the epitaxial structure is converted into red light through the color conversion layer, thereby reducing the cost of the red light-emitting device.

[0471] For example, the light uniformity layer 70 can improve the uniformity of light emitted by the backlight module 20 .

[0472] It is understandable that, when the arrangement density of multiple light-emitting devices is constant, the uniformity of the light emitted by the backlight module 20 is directly proportional to the optical distance (the optical distance here is the distance between the light-leveling layer 70 and the substrate 30). The greater the optical distance, the higher the uniformity of the light emitted by the backlight module. Without considering the thickness of the backlight module, the optical distance can be used to control the uniformity of the light emitted by the backlight module. The area within the optical distance is air and will not affect the polarization degree of the incident light.

[0473] The inventor simulated the light uniformity at different optical distances in the backlight module, and calculated and plotted Figure 75.

[0474] As shown in FIG75 , as the optical distance continues to increase, the light uniformity of the backlight module continues to improve.

[0475] Illustratively, the light-homogenizing layer 70 has a low degree of depolarization and a weak depolarization effect on light, thereby only depolarizing a small amount of single-polarized light (such as TM light) emitted by the light-emitting device, thereby avoiding a significant reduction in the degree of polarization of the backlight provided by the backlight module.

[0476] For example, the backlight module 20 includes multiple light-homogenizing layers 70 , thereby making the light uniform by using the multiple light-homogenizing layers 70 , thereby reducing the optical distance and further reducing the thickness of the backlight module, which is beneficial to the lightweight design of the backlight module and the display device.

[0477] In addition, the inventors conducted simulations on the cases where the backlight module includes different numbers of uniform light layers, calculated the light uniformity of the backlight module, and plotted Figures 76 to 78.

[0478] As shown in FIG76 , as the number of uniform light layers increases, the light uniformity of the backlight module is improved to a certain extent.

[0479] Figure 77 shows the case of two dodging layers, where the horizontal axis represents the positional offset between the two dodging layers. It can be seen that the positional offset between the dodging layers has little effect on the light uniformity of the backlight module.

[0480] As shown in Figure 78, as the number of stacked dodging layers increases, the light propagation path changes multiple times during transmission between the multiple dodging layers, which increases the degree of deflection of the light by the multiple dodging layers. As the number of stacked dodging layers increases, the light output uniformity of the backlight module gradually increases.

[0481] In some embodiments, as shown in FIG. 79 , the light-homogenizing layer 70 includes a main body 71 and a plurality of micro-transparent structures 72 .

[0482] Exemplarily, a plurality of micro-permeable structures 72 are located on the body 71. Each micro-permeable structure 72 extends along a first direction X, and the plurality of micro-permeable structures 72 are arranged along a second direction Y.

[0483] Exemplarily, the multiple micro-permeable structures 72 have the same shape, and the intervals between the multiple micro-permeable structures 72 are the same.

[0484] For example, light incident on the plurality of micro-transparent structures 72 may be emitted through the plurality of micro-transparent structures 72. The micro-transparent structures 72 are configured to homogenize the light emitted by the light emitting device 40 and / or collimate the light emitted by the light emitting device 40.

[0485] For example, the micro-transparent structure 72 is configured to homogenize the light emitted by the light emitting device 40. The light homogenization layer can control the transmission path of the light emitted by the light emitting device, thereby achieving homogenization of the light emitted by the light emitting device 40.

[0486] For example, the micro-transmissive structure 72 is configured to collimate the light emitted by the light emitting device 40 .

[0487] For example, among the light emitted by the light emitting device 40 and incident on the micro-transmissive structure 72, the micro-transmissive structure 72 can converge the light at a large angle into a small angle, so that the light intensity of the light at the small angle is increased, thereby achieving collimation of the light.

[0488] In some embodiments, as shown in FIG. 79 , the surface of the micro-transparent structure 72 close to the plurality of light-emitting devices 40 is an arched surface.

[0489] For example, the light emitted by the light emitting device 40 is incident on the above-mentioned arched surface and changes its emission direction at the arched surface, so that the emission direction of the light is close to the normal direction of the backlight module, thereby enhancing the light intensity of the light emitted close to the normal direction, improving the uniformity of the light output of the backlight module, and allowing part of the light to be close to collimated emission.

[0490] In some embodiments, as shown in FIG. 79 , a ratio of the arch height H1 to the arch diameter K is less than or equal to 1.5.

[0491] For example, the ratio of the arch height H1 to the arch diameter K may be 1.5, 1.4, 1.3, 1.2 or 1.1.

[0492] The inventors simulated the micro-transmitter structure 72 with different arch heights and different arch diameters to obtain the deflection and uniformity of the light by the micro-transmitter structure 72, and plotted them as Figures 80 and 81.

[0493] Figures 80 and 81 show that when the arch height is less than or equal to 75μm, the uniformity of the dodging layer is low. When the arch aperture is approximately 50μm, the uniformity of the backlight module is maximized after the dodging layer evens out the light emitted by multiple light-emitting devices. Therefore, when the aperture is approximately 50μm and the ratio of arch height to aperture is ≤1.5, the uniformity is less than 1%, and the dodging layer has good light uniformity.

[0494] Therefore, by setting the ratio of the arch height to the arch aperture to be less than or equal to 1.5, the depolarization degree of the light-emitting layer can be lower and the light output uniformity of the backlight module can be higher, thereby improving the uniformity of the backlight provided by the backlight module and making the single-polarized light emitted by the light-emitting device almost not depolarized by the light-emitting layer.

[0495] The inventors simulated dodging layers with different apertures and arch heights, calculating the dodging layer's deflection coefficient and light uniformity. Specifically, when the microlens arch diameter was 8μm and the microlens arch height was 4μm to 5μm, the dodging layer's deflection coefficient was 0.3%, and the nine-point uniformity of the light output was 61%. When the microlens arch diameter was 32μm and the microlens arch height was 8μm to 9μm, the deflection coefficient was 0.4%, and the nine-point uniformity of the light output was 81%.

[0496] The inventors also simulated micro-transparent structures with different arch heights in the light-homogenizing layer (the aperture of the micro-transparent structure is 50 μm), calculated the light collimating effect of the light-homogenizing layer, and plotted Figures 82 to 83.

[0497] In Figures 82 and 83, 5, 10...100 indicate that the arch heights of the micro-transmitted structures are 5μm, 10μm...100μm respectively.

[0498] Figures 82 and 83 show that micro-transmitter structures with different arch heights have different light collimation or focusing capabilities. When the arch height to aperture ratio is 1.5 (that is, for a 50μm aperture micro-transmitter structure with an arch height of 75μm), the half-width at half-peak of the micro-transmitter's focusing angle is within ±20°, indicating strong focusing capabilities.

[0499] Therefore, setting the ratio of the micro-transmitter structure arch height to the aperture to be less than or equal to 1.5 can enhance the collimation effect of the light-dotting layer.

[0500] It's understandable that the micro-transparent structure focuses wide-angle light onto a narrower angle, thus enhancing the light intensity within that narrow angle. This enhancement can be characterized by the Enhancement Factor (EF). The Enhancement Factor is the ratio of the brightness within the normal viewing angle (where the angle between the outgoing light and the normal to the backlight module is approximately 0°) with a uniform layer to the brightness within the normal viewing angle without a uniform layer.

[0501] Taking the square arrangement of multiple light-emitting devices in the backlight module as an example, the inventors conducted simulations for different apertures and arch heights of the micro-transmitter structure, calculated the corresponding gain coefficients, and plotted Figures 84 and 85.

[0502] As shown in Figure 84, the aperture of the microlens is less than 300μm, and the gain coefficient of the microlens structure is around 1.6. When the aperture of the microlens is comparable to the arrangement position of multiple light-emitting devices, the light-emitting devices are equivalent to being placed at the focal point of the microlens. The gain coefficient of the microlens structure is maximized, and the light-gathering layer's focusing ability is enhanced.

[0503] As shown in Figure 85, the gain coefficient is large when the micro-permeable structure has a height less than 80 μm. Therefore, when the aperture of the micro-permeable structure is set to 50 μm and the ratio of the micro-permeable structure's height to the aperture is less than or equal to 1.5, the gain coefficient is large, reaching 1.6. This allows the light-leveling layer to have a stronger collimating effect on the light and achieve better light uniformity.

[0504] In some embodiments, as shown in FIG. 86 , the backlight module 20 further includes a first barrier layer 81 and an encapsulation layer 90 .

[0505] For example, the first barrier layer 81 and the encapsulation layer 90 are both located between the light emitting device 40 and the light uniforming layer 70 .

[0506] Illustratively, the first barrier layer 81 is located on the substrate 30 .

[0507] In some examples, the first barrier layer 81 is located between two adjacent light emitting devices 40 and contacts the side surfaces of the light emitting devices 40. The first barrier layer 81 is configured to absorb light incident on the first barrier layer 81 through the side surfaces of the light emitting devices 40.

[0508] Exemplarily, the material of the first barrier layer 81 is a black light-shielding material.

[0509] It can be understood that the light-emitting devices 40 with different filling patterns in Figure 86 represent light-emitting devices 40 that emit light of different colors. As can be seen from the above, the light emitted from the side of the light-emitting device 40 is generally non-single polarized light. With the above-mentioned setting method, the first barrier layer 81 can be used to absorb the light emitted from the side of the light-emitting device 40, thereby improving the polarization degree of the backlight provided by the backlight module, avoiding the light emitted from the side of the light-emitting device 40 from exiting the backlight module, and thus avoiding the influence of this part of the light on the polarization degree of the backlight provided by the backlight module. In addition, the above-mentioned setting method can also reduce the crosstalk phenomenon between the light emitted by adjacent light-emitting devices 40, thereby improving the display effect of the display device.

[0510] In some examples, the encapsulation layer 90 covers the plurality of light emitting devices 40 and the first barrier layer 81 .

[0511] With this arrangement, the encapsulation layer 90 isolates the light-emitting devices 40 and the first barrier layer from the outside world, protecting the multiple light-emitting devices 40 and the first barrier layer 81. This prevents water, oxygen, and other external elements from entering the light-emitting devices 40 or the first barrier layer, thereby reducing the lifespan of the light-emitting devices 40 and the absorption effect of the first barrier layer. Furthermore, the encapsulation layer 90 optimizes the distribution of light emitted by the light-emitting devices 40, thereby improving the light extraction efficiency of the light-emitting devices 40.

[0512] Exemplarily, the material of the encapsulation layer 90 is a highly transparent material. For example, the material of the encapsulation layer 90 can be OCA, which has a transmittance of 98% when the wavelength of the incident light is 450nm. This can prevent the encapsulation layer 90 from absorbing the light emitted by the light-emitting device 40, thereby reducing the light loss of the backlight module.

[0513] For example, the average thickness of the encapsulation layer 90 may be in the range of tens of micrometers to hundreds of micrometers.

[0514] For example, the average thickness of the encapsulation layer 90 may be in the range of 200 μm to 300 μm.

[0515] In some other embodiments, as shown in FIG. 87 , the backlight module 20 further includes: an encapsulation layer 90 and a second barrier layer 82 .

[0516] For example, the second barrier layer 82 and the encapsulation layer 90 are both located between the light emitting device and the light uniforming layer 70 .

[0517] Exemplarily, the encapsulation layer 90 is located on the substrate 30 and covers the plurality of light-emitting devices 40 .

[0518] By adopting the above configuration, the encapsulation layer 90 is used to isolate the light emitting device 40 from the outside world, thereby protecting the multiple light emitting devices 40 and preventing the invasion of external water, oxygen, etc. into the light emitting device 40, thereby avoiding affecting the life of the light emitting device 40.

[0519] Exemplarily, the second barrier layer 82 is located on a side of the encapsulation layer 90 away from the plurality of light-emitting devices 40 .

[0520] Illustratively, the second barrier layer 82 includes a plurality of openings 83 , and one opening 83 is directly opposite to one light emitting device 40 . The second barrier layer 82 is configured to absorb or reflect light incident on the second barrier layer 82 from the light emitting device 40 .

[0521] For example, light emitted from the main light-emitting surface of the light-emitting device 40, after passing through the encapsulation layer, is emitted from the corresponding opening in the second barrier layer 82. Light emitted from the side of the light-emitting device 40 is emitted from the second barrier layer 82 after passing through the encapsulation layer 90 and is absorbed or reflected by the second barrier layer 82, thereby improving the polarization degree, contrast, and light extraction efficiency of the backlight provided by the backlight module 20. Light emitted from the side of the light-emitting device 40 that has not passed through the metal wire grid 43 is prevented from being emitted from the uniform light layer, thereby avoiding reducing the polarization degree of the backlight provided by the backlight module 20. In addition, the above-mentioned arrangement can also prevent crosstalk between light emitted by adjacent light-emitting devices 40, thereby improving the display effect of the display device.

[0522] The light emission of the backlight module provided in the embodiment of the present disclosure is described below.

[0523] For a backlight module without the first light conversion layer, the light emitted by the light emitting device is only TM light, and the light emission utilization rate of the light emitting device is only 50%.

[0524] The backlight module in the present disclosure includes the above-mentioned first light conversion layer. Among the light emitted by the epitaxial structure, TM light is emitted through the metal wire grid, and TE light is reflected from the metal wire grid to the first light conversion layer. After the traveling direction and polarization direction are changed by the first light conversion layer, it is incident on the metal wire grid again. In this process, the reflectivity of the TE light in the metal wire grid is about 90%, and the reflectivity in the first light conversion layer is about 90%. The TE light passes through the epitaxial structure and the buffer layer and other film layers twice, and the transmittance in the film layer is 80%. The proportion of TE light in the light emitted by the epitaxial structure is 50%. Therefore, the light output utilization rate of the backlight module in the present disclosure is 75.9% (specifically calculated by 50% + 90% × 2 × 80% × 2). Compared with the backlight module without the first light conversion layer, the brightness of the backlight provided by the backlight module can be increased by 51.8% (specifically, (75.9% - 50%) / 50% = 51.8%).

[0525] In some embodiments, the display device further includes a polarizer positioned between the backlight module and the display panel. The polarizer can filter light emitted from the light-emitting side of the backlight module, allowing the display panel to receive light with a higher degree of polarization, such as a degree of polarization greater than or equal to 0.99994, thereby achieving a gain in light efficiency of the backlight module of more than 20% and reducing the power consumption of the display device by approximately 20%.

[0526] Some embodiments of the present disclosure also provide a method for preparing the light-emitting device 40 described above, as shown in Figures 88 to 90. First, an epitaxial structure 42 is provided. A light-transmitting dielectric material, such as PMMA or resin, is spin-coated on the surface of the epitaxial structure 42. The light-transmitting dielectric material is then patterned using a nanoimprint process to form a light-transmitting dielectric pattern 4302. A metal material is then deposited on the light-transmitting dielectric pattern 4302 to form a first metal layer and a second metal layer. The light-transmitting dielectric pattern, the first metal layer, and the second metal layer constitute a metal wire grid 43.

[0527] For example, a magnetron sputtering process may be used to deposit metal material on the light-transmitting medium pattern 4302 and the area between two adjacent light-transmitting medium patterns.

[0528] Regarding the structural features of the metal wire grid 43 , reference may be made to the description in some of the above embodiments, which will not be repeated here.

[0529] As shown in Figures 91 to 95, the method for manufacturing the light-emitting device 40 further includes: providing a substrate 001, spin-coating a resin material on the substrate 001 to form a first thin film 002, patterning the first thin film 002 and then etching to form a first pattern 003, wherein the first pattern 003 and a portion of the substrate 001 form a nanorod structure 414, and depositing a metal material on the first pattern 003 to form a first reflective layer 45. The entire structure consisting of the substrate 001, nanorod structure 414, and first reflective layer 45 is bonded to the side of the epitaxial structure 42 away from the metal wire grid 43 to form the light-emitting device 40.

[0530] For example, the process for patterning the first thin film may be a nanoimprint process or a plasma etching process.

[0531] For example, the shape of the first pattern may be a column, and the angle between the sidewall of the column and the substrate may be an acute angle, so that metal material is deposited on the sidewall of the first pattern, thereby ensuring the integrity of the nanocolumn structure.

[0532] For example, the material of the substrate may be sapphire or the like.

[0533] Regarding the structural features of the nanocolumn structure, reference may be made to the descriptions in some of the above embodiments, which will not be repeated here.

[0534] Exemplarily, the method for manufacturing the light-emitting device further includes: forming an encapsulation layer on a side of the metal wire grid 43 away from the epitaxial structure.

[0535] For example, the material of the encapsulation layer may be a light-transmitting material.

[0536] In addition, the metal wire grid in the above-mentioned light-emitting device can also be formed by spraying metal material on the packaging layer after the packaging layer of the light-emitting device is prepared to form a first metal pattern and a second metal pattern, thereby forming a metal wire grid.

[0537] In some embodiments, after the above-mentioned light-emitting device 40 is prepared, a substrate can be provided, and the light-emitting device 40 can be transferred and fixed to the substrate 30, and a random inspection can be performed to detect the fixation yield of the light-emitting device. The light-emitting device and the substrate can be fixed using a reflow soldering process. Then, a reflective layer is formed on the substrate, the reflective layer has an opening, and the light-emitting device is located in the opening. Glue is dispensed around the light-emitting device to form an encapsulation layer, etc., and then it is bound to the FPC (Flexible Printed Circuit) to complete the preparation of the backlight module.

[0538] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that a person skilled in the art can conceive within the technical scope disclosed in the present disclosure should be included within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A light emitting device, comprising: a first light conversion layer; an epitaxial structure located on the first light conversion layer, the epitaxial structure being used to emit light; at least one metal wire grid located on the epitaxial structure; Wherein, the first light conversion layer is configured to change the traveling direction of part of the light incident on the first light conversion layer, so that the light after the traveling direction is changed is emitted in the direction toward the metal wire grid, and the polarization direction of at least part of the light after the traveling direction is changed is changed.

2. The light emitting device according to claim 1, wherein: The first light conversion layer includes: a phase conversion layer; The phase conversion layer includes: a plurality of nano-column structures; the plurality of nano-column structures are arranged in an array.

3. The light emitting device according to claim 2, further comprising: A first reflective layer covers the top surface and side surfaces of each nanorod structure.

4. The light emitting device according to claim 1, wherein: The first light conversion layer includes: a specular reflection layer; The specular reflection layer is configured to reflect a portion of the light incident on the specular reflection layer; The reflectivity of the mirror reflection layer is greater than or equal to 80%.

5. The light emitting device according to claim 1, wherein: The first light conversion layer includes: a scattering reflection layer; The scattering reflection layer is configured to scatter or reflect part of the light incident on the scattering reflection layer, and convert at least part of the light scattered or reflected by the scattering reflection layer into natural light; The roughness of the scattering reflection layer is greater than or equal to 2 μm.

6. The light emitting device according to any one of claims 1 to 5, further comprising: a second light conversion layer between the epitaxial structure and the at least one metal wire grid; The second light conversion layer is configured to reflect or transmit part of the light incident to the second light conversion layer, and change the polarization direction of at least part of the light emitted after passing through the second light conversion layer.

7. The light emitting device according to claim 6, wherein: The second light conversion layer is further configured to change the color of a portion of the light incident on the second light conversion layer.

8. The light emitting device according to any one of claims 1 to 7, wherein: The metal wire grid comprises: A first metal layer includes a plurality of first metal patterns; the plurality of first metal patterns extend along a first direction and are arranged at intervals along a second direction; the first direction intersects with the second direction; a light-transmitting medium layer, comprising a plurality of light-transmitting medium patterns, each of which extends along the first direction, and a plurality of the light-transmitting medium patterns are arranged at intervals along the second direction; and the light-transmitting medium pattern is located between two adjacent first metal patterns; The second metal layer includes a plurality of second metal patterns, each of which extends along the first direction, and the plurality of second metal patterns are arranged at intervals along the second direction; one second metal pattern is located on one of the light-transmitting medium patterns.

9. The light emitting device according to claim 8, wherein: In a direction perpendicular to the plane where the metal wire grid is located and in the second direction, a cross-sectional shape of the light-transmitting medium pattern includes an inverted trapezoid.

10. The light emitting device according to claim 8 or 9, wherein: A size of the first metal pattern along the second direction is substantially equal to a size of the second metal pattern along the second direction.

11. The light emitting device according to any one of claims 8 to 10, wherein: The thickness of the first metal pattern is substantially equal to the thickness of the second metal pattern.

12. The light emitting device according to any one of claims 8 to 11, wherein: The thickness of the first metal pattern is in the range of 20 nm to 80 nm; and / or the thickness of the second metal pattern is in the range of 20 nm to 80 nm.

13. The light emitting device according to any one of claims 8 to 12, wherein: The refractive index of the light-transmitting medium pattern is in the range of 1.4 to 1.

5.

14. The light emitting device according to any one of claims 8 to 13, wherein: When the light emitting device emits blue light, a repetition period of the second metal pattern in the second direction is less than or equal to 140 nm; And / or, the thickness of the light-transmitting medium pattern is in the range of 60 nm to 80 nm; And / or, a size of the light-transmitting medium pattern in the second direction ranges from 50 nm to 70 nm.

15. The light emitting device according to any one of claims 8 to 13, wherein: When the light emitting device emits green light or red light, a repetition period of the second metal pattern in the second direction is less than or equal to 240 nm; And / or, the thickness of the light-transmitting medium pattern is in the range of 70 nm to 90 nm; And / or, a size of the light-transmitting medium pattern in the second direction ranges from 110 nm to 130 nm.

16. The light emitting device according to any one of claims 1 to 15, further comprising: A buffer layer is located between the epitaxial structure and the at least one metal wire grid. The light-emitting device according to claim 16 , wherein the buffer layer has a thickness ranging from 60 nm to 80 nm.

18. The light emitting device according to claim 16 or 17, wherein: The refractive index of the buffer layer is in the range of 1.4 to 1.

5.

19. The light emitting device according to any one of claims 1 to 18, further comprising: a second reflective layer; The second reflective layer at least surrounds the first light conversion layer and the side surface of the epitaxial structure, and the second reflective layer is configured to reflect the light incident on the second reflective layer and make the reflected light emitted to the light emitting side of the light emitting device.

20. A backlight module, comprising: substrate; A plurality of light emitting devices according to any one of claims 1 to 19 are located on the substrate.

21. The backlight module according to claim 20, further comprising: At least one light-homogenizing layer is located on the plurality of light-emitting devices.

22. The backlight module according to claim 21, wherein: The light homogenization layer comprises: ontology; A plurality of micro-permeable structures are located on the body; each micro-permeable structure extends along a first direction, and a plurality of the micro-permeable structures are arranged along a second direction; Wherein, the micro-transmissive structure is configured to perform a homogenization process on the light emitted by the light-emitting device; and / or to perform a collimation process on the light emitted by the light-emitting device.

23. The backlight module according to claim 22, wherein: A surface of the micro-transparent structure close to the plurality of light-emitting devices is an arched surface.

24. The backlight module according to claim 23, wherein: The ratio of the arch height to the arch diameter is less than or equal to 1.

5.

25. The backlight module according to any one of claims 20 to 24, further comprising: a first barrier layer located on the substrate, wherein the first barrier layer is located between two adjacent light-emitting devices and contacts the side surfaces of the light-emitting devices; The first blocking layer is configured to absorb light incident on the first blocking layer through the side of the light-emitting device; The encapsulation layer covers the plurality of light emitting devices and the first barrier layer.

26. The backlight module according to any one of claims 20 to 24, further comprising: an encapsulation layer, located on the substrate and covering the plurality of light-emitting devices; The second barrier layer is located on a side of the encapsulation layer away from the plurality of light-emitting devices; the second barrier layer comprises a plurality of openings; one opening is directly opposite to a light-emitting device; the second barrier layer is configured to absorb or reflect light incident from the light-emitting device to the second barrier layer.

27. A display device comprising: A plurality of light emitting devices according to any one of claims 1 to 19; Or, the backlight module as described in any one of claims 20 to 26.

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