Light-emitting device, display device having the same, and lighting device

Abstract

The present invention provides a light-emitting device, a display device and an illumination device having the same. The light-emitting device includes a light-emitting unit arranged in a sub-region, the light-emitting unit including a stacked light-emitting functional layer, a light extraction functional layer and a partially transparent substrate, the light extraction functional layer being located on the light-emitting side of the light-emitting functional layer, a straight line passing through the geometric center of the light-emitting surface of the light-emitting unit and connected to the edge line of the light-emitting unit at both ends being defined as a first straight line, the shortest length of the first straight line being W, the thickness of the light-emitting unit being T in a direction perpendicular to the transparent substrate, and by making T less than W, the light extraction functional layer can meet generally applicable application conditions, thereby achieving a significant light extraction effect regardless of whether it is applied to a small-area light-emitting device or a large-area light-emitting device, thereby improving the light extraction efficiency of the light-emitting unit and extending the service life of the device.

Description

Technical Field

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

[0002] Light extraction technology is widely used in both display devices and lighting. The former is used to collect and expand the light emitted by LED lamp beads, which are similar to "point light sources", to the entire plane, and to concentrate the light through some light extraction structures such as prism arrays and emit it in the direction of the filter. Completely different from converting a point light source into a surface light source, lighting panels such as OLED are themselves a surface light source with soft light and no need for brightness uniformity. The application of light extraction structures is mainly to guide out the light that cannot be emitted due to total reflection in the OLED device structure, thereby improving the overall light output efficiency of the device and extending the service life of the device.

[0003] Aside from these "surface light sources," it's rare to see point-light-source-like micro-light-emitting devices employing light extraction structures, such as pixels. This is because existing light extraction structures are often applied blindly. These so-called light extraction structures not only have limited light extraction effects on small-area devices, but also offer limited improvements in light output. Improper configuration can also lead to light mixing, such as the mixing of RGB sub-pixels to produce white light, resulting in inaccurate image presentation. Consequently, light extraction technology is generally considered inapplicable to micro-light-emitting devices. Summary of the Invention

[0004] The main purpose of the present invention is to provide a light emitting device, a display device and an illumination device having the same, so as to solve the problem in the prior art that the light extraction structure is not suitable for small-area light emitting devices.

[0005] To achieve the above-mentioned purpose, according to one aspect of the present invention, a light-emitting device is provided, comprising: a light-transmitting substrate; an isolation structure, which is arranged on a first surface of the light-transmitting substrate, and at least one sub-region is formed between the isolation structures; a light-emitting functional layer, which is arranged in a one-to-one correspondence in the sub-region, and the light-emitting functional layer includes a reflective electrode; a light extraction functional layer, which is arranged in a one-to-one correspondence with the light-emitting functional layer; the light-emitting functional layer, the light extraction functional layer and the part of the light-transmitting substrate that correspond to each other and are stacked one by one constitute each light-emitting unit; the structure of each light-emitting unit is selected from one of structures A, B and C, wherein structure A is a light-emitting functional layer, a light extraction functional layer and a part of the light-transmitting substrate that are stacked in sequence, and structure B is a light-emitting functional layer, a part of the light-transmitting substrate and a light extraction functional layer that are stacked in sequence. Take the functional layers, structure C is a light extraction functional layer, a light emitting functional layer and a partially transparent substrate stacked in sequence; the light emitting direction of structure A and structure B is the direction from the reflective electrode to the transparent substrate, and the light emitting direction of structure C is the direction from the reflective electrode to the light extraction functional layer; define a straight line segment passing through the geometric center of the light emitting surface of each light emitting unit and connected to the edge line of the light emitting surface at both ends as the first straight line segment, and the shortest length of the first straight line segment is W; in the direction perpendicular to the transparent substrate, in structure A and structure B, the thickness of the light emitting unit minus the thickness of the reflective electrode is defined as T, and in structure C, the total thickness of the light extraction functional layer and the light emitting functional layer minus the thickness of the reflective electrode is defined as T; in structure A, structure B and structure C, T is less than W.

[0006] Furthermore, T / W ≤ 1 / 10, preferably T / W ≤ 1 / 20, more preferably T / W ≤ 1 / 30.

[0007] Furthermore, 300nm≤T≤1mm, W≥3μm.

[0008] Furthermore, the light emitting surface is a polygon formed by a plurality of straight line segments or a figure surrounded by arc segments. Preferably, the light emitting surface of each sub-region is independently selected from any one of a rectangle, a circle, an ellipse and a diamond.

[0009] Furthermore, the light-emitting functional layer includes a light-transmitting electrode, a light-emitting layer and a reflective electrode, and the light-transmitting electrode and the reflective electrode are independently located on both sides of the light-emitting layer.

[0010] Furthermore, the light-emitting functional layer also includes a hole injection transport layer and an electron injection transport layer, which are located on both sides of the light-emitting layer, and the light-transmitting electrode is located on the side of the hole injection transport layer or the electron injection transport layer away from the light-emitting layer. Preferably, the light-emitting layer is a quantum dot material layer or an organic light-emitting material layer.

[0011] Furthermore, the light extraction functional layer includes a light extraction layer and an interface layer, and the interface layer is located between the light-transmitting electrode and the light extraction layer.

[0012] Furthermore, the light emitting device includes a plurality of light emitting units for emitting light of different colors, and the light of different colors is independently selected from at least one of red light, green light, blue light and white light.

[0013] Furthermore, the light-emitting device is any one of an OLED device, an LED device and a QLED device.

[0014] According to another aspect of the present invention, a display device is provided, including a light-emitting device, wherein the light-emitting device is the light-emitting device described above, the isolation structure is a pixel isolation structure, and the sub-region is a sub-pixel region.

[0015] According to another aspect of the present invention, a lighting device is provided, comprising a light-emitting device, wherein the light-emitting device is the light-emitting device described above, and the isolation structure is a frame, wherein a light-emitting unit is provided in the frame.

[0016] By applying the technical solution of the present invention, a light-emitting device is provided, which includes a light-emitting unit arranged in a sub-region, the light-emitting unit including a stacked light-emitting functional layer, a light extraction functional layer and a partially transparent substrate, the light extraction functional layer is located on the light-emitting side of the light-emitting functional layer, and a straight line passing through the geometric center of the light-emitting surface of the light-emitting unit and connected to the edge line of the light-emitting unit at both ends is defined as a first straight line, the shortest length of the first straight line is W, and the thickness of the light-emitting unit in the direction perpendicular to the transparent substrate is T. By making T less than W, the light extraction functional layer can meet generally applicable application conditions, so that whether it is applied to a small-area light-emitting device or a large-area light-emitting device, it can have a significant light extraction effect, thereby improving the light extraction efficiency of the light-emitting unit and extending the service life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 A partial cross-sectional schematic diagram of a top-emitting light-emitting device provided according to an embodiment of the present invention is shown;

[0019] Figure 2 A partial cross-sectional schematic diagram of a bottom-emitting light-emitting device provided according to an embodiment of the present invention is shown;

[0020] Figure 3 A partial cross-sectional schematic diagram of another bottom-emitting light-emitting device provided according to an embodiment of the present invention is shown;

[0021] Figure 4Schematic diagrams of top views of the positions of first straight line segments in light-emitting surfaces of different top-emitting light-emitting devices provided according to embodiments of the present invention are shown, wherein the dotted line is the first straight line segment with the shortest length.

[0022] The above drawings include the following reference numerals:

[0023] 10. Transparent substrate; 20. Light-emitting layer; 210. Transparent electrode; 220. Light-emitting layer; 230. Reflective electrode; 30. Light extraction layer. DETAILED DESCRIPTION

[0024] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0025] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0026] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present invention described herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0027] As described in the background art, the light extraction structure in the prior art is not suitable for small area light emitting devices. The inventors of this application have conducted research on the above problem and proposed a light emitting device, such as Figures 1 to 3 As shown, it includes a light-transmitting substrate 10, an isolation structure, a light-emitting functional layer 20 and a light extraction functional layer 30. The isolation structure is arranged on the first surface of the light-transmitting substrate 10, and at least one sub-region is formed between the isolation structures; the light-emitting functional layer 20 is arranged in the sub-region one by one, and the light-emitting functional layer includes a reflective electrode 230; the light extraction functional layer 30 is arranged one by one with the light-emitting functional layer 20.

[0028] The above-mentioned one-to-one corresponding and stacked light-emitting functional layer 20, light extraction functional layer 30, and partially transparent substrate 10 constitute each light-emitting unit; the structure of each light-emitting unit is selected from one of Structure A, Structure B, and Structure C. Structure A is a light-emitting functional layer 20, a light extraction functional layer 30, and a partially transparent substrate 10 stacked in sequence; Structure B is a light-emitting functional layer 20, a partially transparent substrate 10, and a light extraction functional layer 30 stacked in sequence; Structure C is a light extraction functional layer 30, a light-emitting functional layer 20, and a partially transparent substrate 10 stacked in sequence; the light emission direction of Structure A and Structure B is from the reflective electrode 230 to the transparent substrate 10, and the light emission direction of Structure C is from the reflective electrode 230 to the light extraction functional layer 30. "Partially transparent substrate" refers to a transparent substrate corresponding to the contact area with the adjacent layer.

[0029] A straight line segment passing through the geometric center of the light-emitting surface of the light-emitting unit and connected to the edge of the light-emitting surface at both ends is defined as a first straight line segment. The shortest length of the first straight line segment is W, such as Figure 4 As shown, (a) is a rhombus, (b) is a polygon, (c) is a rectangle, and (d) is an ellipse; in the direction perpendicular to the transparent substrate 10, in structures A and B, the thickness of the light-emitting unit minus the thickness of the reflective electrode 230 is defined as T, and in structure C, the total thickness of the light extraction functional layer and the light-emitting functional layer minus the thickness of the reflective electrode 230 is defined as T; in structures A, B, and C, T is less than W.

[0030] Since the light-emitting functional layers in each light-emitting unit are arranged in a one-to-one correspondence in the sub-region, that is, the shape of the cross-section of the sub-region determines the shape of the light-emitting surface of the light-emitting unit, by making the thickness T of the light-emitting unit less than W, the light extraction functional layer can meet generally applicable application conditions, so that whether it is applied to a small-area light-emitting device or a large-area light-emitting device, it can have a significant light extraction effect, thereby improving the light extraction efficiency of the light-emitting unit and extending the service life of the device.

[0031] The light-emitting device of the present invention may include multiple light-emitting units, each of which emits light of a different wavelength through the light-emitting functional layer 20. The incident light of different wavelengths does not only refer to incident light of different single wavelengths, but can also be understood as incident light of different wavelength ranges. The light of different wavelengths can be light of different colors, such as red, green, blue, and white light. Those skilled in the art can reasonably select the number of light-emitting units and the emission wavelength of each light-emitting unit based on actual needs, so that the light-emitting units can be applied to OLED devices, LED devices, or QLED devices.

[0032] The light extraction functional layer 30 in each light-emitting unit is arranged in a one-to-one correspondence with the light-emitting functional layer 20, so that when the incident light of different wavelengths from the light-emitting functional layer 20 passes through specific light extraction layers, the light extraction layers 30 corresponding to the incident light of different wavelengths have different light extraction enhancement ratios, thereby optimizing the external quantum efficiency of light-emitting units of different wavelengths in the light-emitting device, which not only improves the luminous efficiency of the device, but also makes the final external quantum efficiency of each light-emitting unit close, realizes synchronous aging, and extends the service life of the device.

[0033] The above-mentioned light extraction improvement ratio refers to the external quantum efficiency improvement ratio of the light-emitting unit. In some embodiments, the light-emitting unit with the highest original external quantum efficiency is defined as the first light-emitting unit, the light-emitting unit with the lowest original external quantum efficiency is defined as the third light-emitting unit, and the light-emitting unit with an original external quantum efficiency between the first light-emitting unit and the third light-emitting unit is defined as the second light-emitting unit. The external quantum efficiency improvement ratio of the light extraction functional layer 30 to the first light-emitting unit is X1, the external quantum efficiency improvement ratio of the light extraction functional layer 30 to the second light-emitting unit is X2, and the external quantum efficiency improvement ratio of the light extraction functional layer 30 to the third light-emitting unit is X3. X1, X2 and X3 are not equal. Definition Wherein, n is selected from any natural number between 1 and 3, Q1 is the original external quantum efficiency of each light-emitting unit, and Q2 is the actual external quantum efficiency of each light-emitting unit.

[0034] Those skilled in the art can provide light extraction functional layers 30 with different efficiency extraction ratios for light-emitting units of different luminous colors. In some embodiments, the first light-emitting unit can be a light-emitting unit that emits red light, the second light-emitting unit can be a light-emitting unit that emits green light, and the third light-emitting unit can be a light-emitting unit that emits blue light; normally, the original external quantum efficiencies of the first light-emitting unit, the second light-emitting unit, and the third light-emitting unit decrease in sequence. Since the original external quantum efficiencies of the three light-emitting units corresponding to RGB decrease in sequence, the improvement ratio needs to increase in sequence: X3>X2>X1. It should be noted that, under special circumstances, the efficiencies between the above-mentioned light-emitting units may be relatively close or even surpass each other. The light-emitting device having the above-mentioned light-emitting units can be an RGB light-emitting device or an RGBW light-emitting device.

[0035] In some embodiments, in order to utilize the light extraction functional layer 30 to achieve the adjustment of the external quantum efficiency improvement ratio of the light-emitting unit, the above-mentioned light extraction functional layer 30 can be a light scattering layer having scattering particles, and the scattering particles include but are not limited to zinc oxide, aluminum oxide, zirconium oxide, titanium oxide, etc. The raw materials forming the above-mentioned light extraction functional layer 30 can also include various additives, polymers, curable glue, etc.

[0036] In order to enable the light extraction functional layer 30 to have different light extraction enhancement ratios corresponding to incident light of different wavelengths, in some embodiments, the thicknesses of the light extraction functional layers 30 corresponding to incident light of different wavelengths are different, and the thickness of the light extraction functional layer 30 in the first light-emitting unit is defined as H1, the thickness of the light extraction functional layer 30 in the second light-emitting unit is defined as H2, and the thickness of the light extraction functional layer 30 in the third light-emitting unit is defined as H3, and H1, H2 and H3 are not equal.

[0037] In other embodiments, the volume percentage of the scattering particles in the above-mentioned light extraction functional layer 30 is used to adjust the external quantum efficiency improvement ratio of the light-emitting unit. The volume percentage of the scattering particles in the light extraction functional layer 30 of the first light-emitting unit is defined as V1, the volume percentage of the scattering particles in the light extraction functional layer 30 of the second light-emitting unit is defined as V2, and the volume percentage of the light extraction functional layer 30 of the third light-emitting unit is defined as V3. V1, V2 and V3 are not equal.

[0038] In other embodiments, the refractive index of the scattering particles in the above-mentioned light extraction functional layer 30 is used to adjust the external quantum efficiency improvement ratio of the light-emitting unit. The refractive index of the scattering particles in the light extraction functional layer 30 of the first light-emitting unit is defined as K1, the refractive index of the scattering particles in the light extraction functional layer 30 of the second light-emitting unit is defined as K2, and the refractive index of the scattering particles in the light extraction functional layer 30 of the third light-emitting unit is defined as K3, and K1, K2 and K3 are not equal.

[0039] In addition to using a light scattering layer containing scattering particles as the light extraction functional layer 30, the light extraction functional layer 30 may also be a homogeneous material layer. When the light extraction functional layer 30 is a homogeneous material layer, the material forming the light extraction functional layer 30 may be selected from any one of a polymer resin, metal oxide particles, and a semiconductor material.

[0040] The above-mentioned light extraction functional layer 30 can also be a refractive index gradient material layer. The material forming the light extraction functional layer 30 can be selected from a variety of polymer resins, metal oxide particles and semiconductor materials, such as a scattering system formed by stacking multiple semiconductor materials, or gradually changing the sputtering atmosphere to cause a slight change in the components of the metal compound, thereby obtaining a metal compound layer with a continuously changing n value, whose effective refractive index = (volume fraction of the first component × refractive index of the first component) + (volume fraction of the second component × refractive index of the second component) +... (volume fraction of the nth component × refractive index of the nth component), n is greater than 1.

[0041] In order to improve the light extraction effect of the light extraction function layer 30 when applied to a light emitting device, preferably, T / W ≤ 1 / 10, more preferably, T / W ≤ 1 / 20, and even more preferably, T / W ≤ 1 / 30.

[0042] In order to enable the light extraction function layer 30 to have a significant light extraction effect in both a small-area light-emitting device and a large-area light-emitting device, preferably, 300 nm ≤ T ≤ 1 mm, and W ≥ 3 μm.

[0043] In the above-mentioned light-emitting device of the present invention, each sub-region has a first cross-section parallel to the transparent substrate 10, and the first cross-section is the same as the shape of the light-emitting surface of the above-mentioned light-emitting unit, and can be composed of a combination of straight line segments and / or arc segments, such as a figure composed of straight line segments and arc segments, a polygon composed of multiple straight line segments, or a figure surrounded by at least one arc segment. The first cross-section of each of the above-mentioned sub-regions and its corresponding light-emitting surface can be selected from any one of a rectangle, a circle, an ellipse, a diamond, or an approximate rectangle, an approximate circle, an approximate ellipse, and an approximate diamond shape.

[0044] In some embodiments, the light-emitting functional layer 20 includes a transparent electrode 210, a light-emitting layer 220, and a reflective electrode 230, wherein the transparent electrode 210 and the reflective electrode 230 are independently located on either side of the light-emitting layer 220. Light generated in the light-emitting layer 220 can be reflected by the reflective electrode 230 and transmitted through the transparent electrode 210 to the light extraction functional layer 30.

[0045] In order to achieve electroluminescence, the above-mentioned light-emitting functional layer 20 may also include a hole injection transport layer and an electron injection transport layer, the hole injection transport layer and the electron injection transport layer are located on both sides of the light-emitting layer 220, and the transparent electrode 210 is located on the side of the hole injection transport layer or the electron injection transport layer away from the light-emitting layer 220, and the above-mentioned light-emitting layer 220 may be a quantum dot material layer or an organic light-emitting material layer.

[0046] When the light emitting functional layer 20 includes the light-transmitting electrode 210, the light extraction functional layer 30 may include a light extraction layer and an interface layer (not shown in the figure), and the interface layer is located between the light-transmitting electrode 210 and the light extraction layer. Figure 1 In the light emitting device shown in FIG. 1 , the interface layer can protect the light-transmitting electrode 210. When the interface layer is provided in the Figure 2 In the light-emitting device shown, the interface layer can be used to planarize the light extraction functional layer 30 to facilitate the smooth application of the transparent electrode 210 .

[0047] In a preferred embodiment, the light emitting device of the present invention is a top emitting light emitting device, and the light-transmitting substrate 10 is located on the side of the light emitting functional layer 20 of the light emitting unit away from the light extraction functional layer 30. Figure 1 shown.

[0048] In another preferred embodiment, the light emitting device of the present invention is a bottom emitting light emitting device, the light emitting unit includes a light-transmitting substrate 10, and the light-transmitting substrate 10 is located on the side of the light extraction functional layer 30 away from the light emitting functional layer 20, such as Figure 2 shown.

[0049] When the light emitting device of the present invention is a bottom-emitting light emitting device, the structure of the light emitting device is not limited to the above preferred embodiment. For example, the light emitting unit includes a light-transmitting substrate 10, and the light-transmitting substrate 10 is located between the light-emitting functional layer 20 and the light extraction functional layer 30. Figure 3 shown.

[0050] According to another aspect of the present invention, a display device is provided, comprising the above-mentioned light-emitting device, wherein the isolation structure in the light-emitting device is a pixel isolation structure, at least one sub-pixel region is formed between the pixel isolation structures, and the light-emitting functional layer 20 and the light extraction functional layer 30 are arranged in the sub-pixel region in a one-to-one correspondence.

[0051] According to another aspect of the present invention, a lighting device is provided, comprising the above-mentioned light-emitting device, wherein the isolation structure in the light-emitting device is a frame, and the above-mentioned light-emitting unit is arranged in the frame.

[0052] The light-emitting device provided in the present application will be further described below with reference to examples and comparative examples.

[0053] Example 1

[0054] The light emitting device provided in this embodiment is a top-emitting light emitting device, such as Figure 1 As shown, it includes a light-transmitting substrate 10, a light-emitting functional layer 20 and a light extraction functional layer 30 stacked in sequence, the light-emitting functional layer 20 includes a light-transmitting electrode 210, a hole injection and transport layer, a light-emitting layer 220, an electron injection and transport layer and a reflective electrode 230, and the light-transmitting electrode 210 and the reflective electrode 230 are independently located on both sides of the light-emitting layer 220, and the light extraction functional layer 30 includes a light extraction layer; the above-mentioned light-emitting device also includes a pixel isolation structure provided on the first surface of the light-transmitting substrate 10, and a 3* is formed between the pixel isolation structures. 3*3 (RGB) sub-pixel areas; the light-emitting functional layer 20 is arranged in the sub-pixel area in a one-to-one correspondence; the light extraction functional layer 30 is arranged in a one-to-one correspondence with the light-emitting functional layer 20, and the one-to-one corresponding and stacked partially transparent substrates 10, light-emitting functional layers 20 and light extraction functional layers 30 constitute each light-emitting unit, and the light emitting direction of each light-emitting unit is the direction from the reflective electrode 230 to the light extraction functional layer 30, and the thickness T of the above-mentioned light-emitting unit is 4μm, the light-emitting surface of the light-emitting unit is rectangular, and the shortest length W is 20μm.

[0055] The above-mentioned light-emitting units include the same number of first light-emitting units emitting red light, second light-emitting units emitting green light, and third light-emitting units emitting blue light. The light-emitting layer in the first light-emitting unit is formed by drying a quantum dot ink including red quantum dots and a solvent, wherein the red quantum dots are CdSe / ZnS. The light-emitting layer in the third light-emitting unit is formed by drying a quantum dot ink including blue quantum dots and a solvent, wherein the blue quantum dots are CdZnS / ZnS. The light-emitting layer in the second light-emitting unit is formed by drying a quantum dot ink including green quantum dots and a solvent, wherein the green quantum dots are CdSe / CdS.

[0056] The light-transmitting electrode 210 is an ITO anode (150nm thick), the hole injection layer is made of polyethylene dioxythiophene: poly(styrene sulfonic acid), and the hole transport layer is made of polyethylene carbazole. The reflective electrode 230 is a cathode made of Ag, and the electron injection and transport layer is made of zinc oxide nanocrystals. The total thickness of the light-emitting layer, hole transport layer, hole injection layer, and electron injection and transport layer of the light-emitting unit is 150nm. The interface layer is 100nm of NPB (N,N′-di(naphthalene-1-yl)-N,N′-di(phenyl)benzidine) produced by vacuum thermal evaporation.

[0057] The light extraction functional layer 30 is formed by curing a mixture of scattering particles and 6108 type UV adhesive in a volume fraction ratio of 50:50. The scattering particles are P25 type titanium dioxide with an average particle size of 21nm. The thickness of the light extraction functional layer 30 is 3600nm.

[0058] Example 2

[0059] The light emitting device provided in this embodiment differs from that in Embodiment 1 in that:

[0060] The thickness T of the light-emitting unit is 1 μm, wherein the total thickness of the functional layers of the light-emitting unit is 150 nm, the transparent electrode ITO is 100 nm, the interface layer NPB is 50 nm, and the light extraction functional layer is 700 nm thick. The shortest length W of the light-emitting surface of the light-emitting unit is 10 μm.

[0061] Example 3

[0062] The light emitting device provided in this embodiment differs from that in Embodiment 1 in that:

[0063] The thickness T of the light-emitting unit is 1 μm. The total thickness of the functional layers is 150 nm, the transparent ITO electrode is 100 nm, the interface layer NPB is 50 nm, and the light extraction functional layer is 700 nm thick. The light-emitting surface of the light-emitting unit is elliptical, with a minimum length W of 20 μm.

[0064] Example 4

[0065] The light emitting device provided in this embodiment differs from that in Embodiment 1 in that:

[0066] The thickness T of the light-emitting unit is 300nm, of which the total thickness of the functional layers of the light-emitting unit is 150nm, the transparent electrode Ag is 15nm, the interface layer NPB is 20nm, and the light extraction functional layer is 115nm thick. The light-emitting surface of the light-emitting unit is diamond-shaped, with a minimum length W of 9μm.

[0067] Example 5

[0068] The light emitting device provided in this embodiment differs from that in Embodiment 1 in that:

[0069] Light-emitting devices such as Figure 3 As shown, it includes a light-emitting functional layer 20, a transparent substrate 10 and a light extraction functional layer 30 stacked in sequence. The thickness T of the light-emitting unit is 0.7 mm, of which the total thickness of the light-emitting functional layer is 150 nm, the thickness of the transparent electrode ITO is 150 nm, the thickness of the transparent substrate is about 0.7 mm, and the light extraction functional layer is 800 nm. The total thickness is approximately the thickness of the transparent substrate, that is, 0.7 mm. (Here the light extraction layer is made on the outside of the substrate away from the device, and no interface layer is required) The shortest length W of the light-emitting surface of the above-mentioned light-emitting unit is 35 mm.

[0070] Example 6

[0071] The light emitting device provided in this embodiment differs from that in Embodiment 1 in that:

[0072] Light-emitting devices such as Figure 2 As shown, the device comprises a sequentially stacked light-emitting functional layer 20, a light extraction functional layer 30, and a light-transmitting substrate 10. The thickness T of the light-emitting unit is 50 μm, including a 150 nm light-emitting functional layer, a 200 nm transparent ITO electrode, a 2.15 μm interface layer, a 2.5 μm light extraction functional layer, and a 45 μm transparent substrate. The shortest length W of the light-emitting surface of the light-emitting unit is 2 mm.

[0073] Comparative Examples 1-6

[0074] The light-emitting devices provided in the above comparative examples are respectively the light-emitting devices in Examples 1 to 6 without the light extraction functional layer 30 .

[0075] The thickness of each embodiment and comparative example was tested using a DEKTAK XT step profiler, and the length was tested using a microscope.

[0076] The external quantum efficiency of the light-emitting devices in the above Examples 1-6 and Comparative Examples 1-6 was tested. The performance test method of the QLED device is mainly divided into two parts: the first part is mainly composed of a Keithley 2400 digital source meter and a probe base, which is mainly used to measure the voltage (V) and current (I) signals of the device, and further obtain the voltage (V)-current density (J) curve when the device is working and the number of electrons passing through the device per unit time; the second part is mainly composed of an integrating sphere, an optical fiber and a spectrometer (QE65000 or QEPro), which is mainly used to measure the spectral data of the front light emission of the device, including the luminescence peak position, half-peak width and the number of luminous photons. Combining the data of the above two parts, the external quantum efficiency (EQE) of the device can be calculated according to the formula. And under a 1000nit white field (a 1000nit white field consists of 300nit red light, 600nit green light and 100nit blue light respectively), the time it takes for the brightness to decay to 980nit (T98) is tested. The test results are shown in the following table.

[0077] / Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 EQE% 11.3 12.7 18.1 20.4 14.5 21.3 T98 / h 2665 2930 5396 6836 3829 7980 / Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 EQE% 9.1 8.9 9.3 9.6 9.4 9.9 T98 / h 1691 1536 1721 1901 1705 2104

[0078] From the above test results, it can be seen that compared with the light-emitting devices in the comparative examples without the light extraction functional layer, the external quantum efficiency of the devices in the above embodiments, whether small-area light-emitting devices or large-area light-emitting devices, is improved by applying the light extraction functional layer, and as the T / W ratio increases, the improvement ratio is also significantly improved. From the time T98 taken for the brightness to decay to 98% of the initial brightness, it can be seen that the life of the devices with the light extraction functional layer is significantly improved. In the first and second groups of devices, the T / W ratio is only about 5 and 10 times, and the improvement ratio of the external quantum efficiency is approximately 24% and 45%. The fifth group of devices is more special. The light extraction functional layer can only extract light in the substrate mode (the so-called external light extraction, and the rest are internal light extraction). Therefore, even if the T / W ratio is large, the improvement of the external quantum efficiency can only reach about 50%, but compared with the first and second groups of devices, the improvement ratio is significantly improved (the first group of devices mentioned above is Example 1 and Comparative Example 1, and so on).

[0079] In some cases, the size of the light-emitting surface is strictly limited, that is, the pixels are getting smaller and smaller. In order to maximize the external quantum efficiency, it is necessary to carefully design the light-emitting path of the device to minimize the T / W ratio to obtain a higher improvement ratio.

[0080] In addition, the devices of Examples 1-6 were visually inspected and observed under a microscope. Except for Example 5 where the edge of the light emitting area was not clear, no light mixing or blurring was found in the other examples. Figure 2 The structure is more suitable for lighting devices, while Figure 1 and Figure 3The structure can be used for display devices by reasonably designing and controlling the optical path according to actual conditions.

[0081] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0082] The shortest length of a straight line passing through the geometric center of the light-emitting surface of the light-emitting unit and connected to the edge of the light-emitting surface at both ends is defined as W. By making the thickness T of the light-emitting unit less than W, the light extraction functional layer can meet generally applicable application conditions, so that whether it is applied to a small-area light-emitting device or a large-area light-emitting device, it can have a significant light extraction effect, thereby improving the light extraction efficiency of the light-emitting unit and extending the service life of the device.

[0083] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A light-emitting device, comprising: a light-transmitting substrate (10); Isolation structures are provided on the first surface of the light-transmitting substrate (10), with at least one sub-region formed between the isolation structures; A light-emitting functional layer (20) is arranged in the sub-regions in a one-to-one correspondence, and the light-emitting functional layer includes a reflective electrode (230); A light extraction functional layer (30) is provided in one-to-one correspondence with the light emitting functional layer (20); The invention is characterized in that the light-emitting functional layer (20), the light extraction functional layer (30) and part of the light-transmitting substrate (10) which are stacked one by one correspond to each other constitute each light-emitting unit; the structure of each light-emitting unit is selected from one of A, B and C, wherein A is the light-emitting functional layer (20), the light extraction functional layer (30) and part of the light-transmitting substrate (10) which are stacked in sequence, B is the light-emitting functional layer (20), part of the light-transmitting substrate (10) and the light extraction functional layer (30) which are stacked in sequence, and C is the light extraction functional layer (30), the light-emitting functional layer (20) and part of the light-transmitting substrate (10) which are stacked in sequence; the light emitting direction of A and B is the direction from the reflective electrode (230) to the light-transmitting substrate (10), and the light emitting direction of C is the direction from the reflective electrode (230) to the light extraction functional layer (30); A straight line segment passing through the geometric center of the light-emitting surface of each light-emitting unit and connected to the edge of the light-emitting surface at both ends is defined as a first straight line segment, and the shortest length of the first straight line segment is W; in a direction perpendicular to the light-transmitting substrate (10), in A and B, the thickness of the light-emitting unit minus the thickness of the reflective electrode (230) is defined as T, and in C, the total thickness of the light extraction functional layer and the light-emitting functional layer minus the thickness of the reflective electrode (230) is defined as T; in A, B, and C, T is less than W; T / W≤1 / 10, 300nm≤T≤1mm, W≥3μm.

2. The light emitting device according to claim 1, wherein T / W≤1 / 20.

3. The light emitting device according to claim 1, wherein T / W≤1 / 30.

4. The light emitting device according to any one of claims 1 to 3, characterized in that The light-emitting surface is a polygon formed by a plurality of straight line segments or a figure surrounded by arc segments.

5. The light emitting device according to any one of claims 1 to 3, characterized in that The light emitting surface of each sub-region is independently selected from any one of a rectangle, a circle, an ellipse and a diamond.

6. The light emitting device according to any one of claims 1 to 3, characterized in that The light-emitting functional layer (20) comprises a light-transmitting electrode (210), a light-emitting layer (220), and the reflective electrode (230), and the light-transmitting electrode (210) and the reflective electrode (230) are independently located on both sides of the light-emitting layer (220).

7. The light emitting device according to claim 6, characterized in that The light-emitting functional layer (20) further comprises a hole injection transport layer and an electron injection transport layer, wherein the hole injection transport layer and the electron injection transport layer are located on both sides of the light-emitting layer (220), and the light-transmitting electrode (210) is located on a side of the hole injection transport layer or the electron injection transport layer away from the light-emitting layer (220).

8. The light emitting device according to claim 7, characterized in that The light-emitting layer (220) is a quantum dot material layer or an organic light-emitting material layer.

9. The light emitting device according to claim 6, characterized in that The light extraction functional layer (30) comprises a light extraction layer and an interface layer, and the interface layer is located between the light-transmitting electrode (210) and the light extraction layer.

10. The light emitting device according to any one of claims 1 to 3, characterized in that The light emitting device includes a plurality of light emitting units for emitting light of different colors, wherein the light of different colors is independently selected from at least one of red light, green light, blue light and white light.

11. The light emitting device according to any one of claims 1 to 3, characterized in that The light-emitting device is any one of an OLED device, an LED device and a QLED device.

12. A display device comprising a light emitting device, characterized in that: The light-emitting device is the light-emitting device according to any one of claims 1 to 11, the isolation structure is a pixel isolation structure, and the sub-region is a sub-pixel region.

13. A lighting device comprising a light emitting device, characterized in that: The light-emitting device is the light-emitting device according to any one of claims 1 to 11, the isolation structure is a frame, and one light-emitting unit is arranged in the frame.

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