Color conversion film structure with improved light absorption efficiency, preparation method and application thereof

Abstract

The present invention discloses a color conversion film structure that improves light absorption efficiency, as well as its preparation method and application. The color conversion film structure that improves light absorption efficiency comprises: at least one wavelength conversion layer with micro-nanoscale dimensions and at least two refractive functional layers with micro-nanoscale dimensions, stacked along a selected direction. The difference in refractive index between the refractive functional layer and the adjacent wavelength conversion layer is greater than or equal to 0.2, and the difference in refractive index between adjacent refractive functional layers is greater than or equal to 0.2. By incorporating multiple refractive functional layers, the color conversion film structure provided by the present invention effectively improves light absorption efficiency and has a lifespan far exceeding that of conventional film structures.

Description

Technical Field

[0001] The present invention particularly relates to a color conversion film structure for improving light absorption efficiency, a preparation method thereof, and an application thereof, and belongs to the technical field of optoelectronic devices. Background Art

[0002] Current display development is focused on wide color gamut, high dynamic range, high resolution, low power consumption, and large and miniature displays. LCDs, with their mature technology, low cost, low power consumption, and wide range of applications, have long dominated the display market. With the advent of the metaverse concept, Micro LEDs are experiencing a new surge in popularity.

[0003] Currently, the methods for achieving full color on the market are mainly divided into three-color lamination and quantum dot color conversion (QDCC). The structure of conventional displays with quantum dot color conversion film structures is as follows: Figure 1 and Figure 2 However, so far, three-color bonding has problems such as transfer yield and cost, such as Figure 1 The QDCC structure in the display shown has problems of blue light overflow and short service life. In order to solve the blue light overflow problem, Figure 2 The display shown in the figure introduces inorganic nanoparticles (such as SiO2, TiO2, ZrO2, etc.) as light diffusion materials in the QDCC structure. However, in order to maximize the scattering effect of the inorganic nanoparticles, the particle size of the introduced inorganic nanoparticles needs to reach 150nm-200nm, while the film thickness of the QDCC structure is usually 2-3μm. First, the particle size distribution performance of the inorganic nanoparticles is poor, resulting in the agglomeration of the introduced inorganic nanoparticles, and then there are "large particles" formed by the agglomeration of inorganic nanoparticles in the QDCC structure. ", which leads to the formation of an uneven structure on the film surface of the QDCC structure, which has a great impact on the subsequent process; secondly, when there are too many "large particles" formed by the agglomeration of inorganic nanoparticles in the QDCC structure, it will also affect the subsequent photolithography process of the QDCC structure; thirdly, due to the limitation of the film thickness of the QDCC structure, in order to improve the scattering effect of inorganic nanoparticles, it is bound to lead to a low content of quantum dots in the QDCC structure, which in turn leads to the QDCC structure's absorption of light, the conversion of red and green light, and service life. There are adverse effects. Summary of the Invention

[0004] The main purpose of the present invention is to provide a color conversion film structure with improved light absorption efficiency, a preparation method thereof, and an application thereof, thereby overcoming the deficiencies in the prior art.

[0005] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include:

[0006] On one hand, the present invention provides a color conversion film layer structure for improving light absorption efficiency, comprising at least one wavelength conversion layer and at least two refractive functional layers, wherein the wavelength conversion layer and the refractive functional layer are stacked in sequence, wherein the difference between the refractive index of the refractive functional layer and the refractive index of the adjacent wavelength conversion layer is greater than or equal to 0.2, and the difference between the refractive indices of the adjacent refractive functional layers is greater than or equal to 0.2, the thickness of each wavelength conversion layer is 100-300nm, and the thickness of each refractive functional layer is 20-100nm.

[0007] Furthermore, the wavelength conversion layer is a dense film layer formed by light conversion material.

[0008] Furthermore, the photoconversion material includes quantum dots, and the quantum dots include one or a combination of two or more of CdSe, CdS, CdZnSe, CdZnS, CdZnSeS, ZnSeS, ZnSe, CuInS, CuInSe, InP, InZnP and perovskite quantum dots, but are not limited thereto.

[0009] Furthermore, the content of the quantum dots in the light conversion material is 30 wt%-80 wt%.

[0010] Furthermore, the particle size of the quantum dots is 1-50 nm.

[0011] Furthermore, the refractive functional layer is a dense film layer formed of a refractive functional material.

[0012] Furthermore, the refractive functional material includes metal oxide or inorganic non-metal oxide.

[0013] Furthermore, the refractive functional material includes any one or a combination of two or more of TiO2, ZrO, Al2O3, SiO2, ZnO, SiO, MgF, SiO2, Ti3O5, Ti2O3, TiO, Ta2O5, HfO2, Nb2O5, MgO, Y2O3, AlF3, ZnS, and ZnSe, but is not limited thereto.

[0014] Furthermore, the color conversion film layer structure includes: multiple wavelength conversion layers and multiple refractive functional layers, two or more functional refractive layers are arranged between any two wavelength conversion layers, or the wavelength conversion layers and the refractive functional layers are alternately arranged in sequence.

[0015] Furthermore, the difference between the refractive index of the refractive functional layer and the refractive index of the adjacent wavelength conversion layer is 0.2-2.0, preferably 0.2-1.0, and particularly preferably 0.3-1.0, for example, it can be 0.2, 0.3, 0.4, 0.5, 0.65, 0.85, 1.0, 1.2, 1.45, 1.75, 1.9, 2.0, etc.

[0016] Furthermore, the difference in refractive index between adjacent refractive functional layers is 0.2-2.0, preferably 0.2-1.0, and particularly preferably 0.3-1.0, for example, 0.2, 0.3, 0.4, 0.5, 0.65, 0.85, 1.0, 1.2, 1.45, 1.75, 1.9, 2.0, etc.

[0017] Furthermore, the differences in the refractive indices of the multiple refractive functional layers are all different.

[0018] Furthermore, the thicknesses of any two wavelength conversion layers are the same or different, and the thickness of each wavelength conversion layer can be 100nm, 102nm, 120nm, 130nm, 145nm, 170nm, 193nm, 200nm, 241nm, 265nm, 280nm, 291nm, 300nm, etc.

[0019] Furthermore, the thicknesses of any two of the refractive functional layers are the same or different, and the thickness of each of the refractive functional layers is preferably 20-30 nm. For example, the thickness of each of the refractive functional layers can be 20 nm, 22 nm, 25 nm, 30 nm, 31 nm, 33 nm, 35 nm, 40 nm, 45 nm, 50 nm, 54 nm, 60 nm, 71 nm, 90 nm, 100 nm, etc.

[0020] Furthermore, the thickness of the color conversion film structure is on a micro-nano scale.

[0021] Furthermore, the color conversion film layer structure has a thickness of 2-3 μm.

[0022] Furthermore, the surface of the color conversion film structure is continuous and flat.

[0023] Another aspect of the present invention provides a method for preparing a color conversion film structure with improved light absorption efficiency, comprising:

[0024] At least one wavelength conversion layer and at least two refractive functional layers are manufactured, wherein each wavelength conversion layer has a thickness of 100-300 nm and each refractive functional layer has a thickness of 20-100 nm, and the at least one wavelength conversion layer and the at least two refractive functional layers are sequentially stacked, wherein the difference between the refractive index of the refractive functional layer and the refractive index of the adjacent wavelength conversion layer is greater than or equal to 0.2, and the difference between the refractive indices of the adjacent refractive functional layers is greater than or equal to 0.2, thereby forming the color conversion film layer structure.

[0025] Furthermore, the step of making the wavelength conversion layer includes: forming a dense film layer with a light conversion material, thereby forming the wavelength conversion layer.

[0026] For example, the wavelength conversion layer can be produced by spin coating, spray coating, screen printing, inkjet printing or other film forming methods.

[0027] Furthermore, the photoconversion material includes quantum dots, and the quantum dots include one or a combination of two or more of CdSe, CdS, CdZnSe, CdZnS, CdZnSeS, ZnSeS, ZnSe, CuInS, CuInSe, InP, InZnP and perovskite quantum dots, but are not limited thereto.

[0028] Furthermore, the content of the quantum dots in the light conversion material is 30 wt%-80 wt%.

[0029] Furthermore, the particle size of the quantum dots is 1-50 nm.

[0030] Furthermore, the thickness of any two of the wavelength conversion layers may be the same or different. For example, the thickness of each of the wavelength conversion layers may be 100 nm, 102 nm, 120 nm, 130 nm, 145 nm, 170 nm, 193 nm, 200 nm, 241 nm, 265 nm, 280 nm, 291 nm, 300 nm, etc.

[0031] Furthermore, the step of making the refractive functional layer includes: forming a dense film layer with a refractive functional material, thereby forming the refractive functional layer.

[0032] Furthermore, the step of forming the refractive functional layer includes: forming the refractive functional layer by any one of vapor deposition, optical coating, sputtering, and evaporation. Specifically, the refractive functional layer can be formed by atomic layer deposition (ALD), plasma enhanced chemical vapor deposition (PECVD), optical coating, metal organic chemical vapor deposition (MOCVD), magnetron sputtering, evaporation, etc. More specifically, the growth temperature of the refractive functional layer is 30°C-150°C, preferably 30°C-70°C, and the growth atmosphere is vacuum or a protective gas atmosphere such as N2 and Ar.

[0033] Furthermore, the refractive functional material includes metal oxide or inorganic non-metal oxide.

[0034] Furthermore, the refractive functional material includes any one or a combination of two or more of TiO2, ZrO, Al2O3, SiO2, ZnO, SiO, MgF, SiO2, Ti3O5, Ti2O3, TiO, Ta2O5, HfO2, Nb2O5, MgO, Y2O3, AlF3, ZnS, and ZnSe, but is not limited thereto.

[0035] Furthermore, the thicknesses of any two of the refractive functional layers are the same or different.

[0036] Furthermore, the thickness of each of the refractive functional layers is preferably 20-30 nm. For example, the thickness of each of the refractive functional layers can be 20 nm, 22 nm, 25 nm, 30 nm, 31 nm, 33 nm, 35 nm, 40 nm, 45 nm, 50 nm, 54 nm, 60 nm, 71 nm, 90 nm, or 100 nm.

[0037] Furthermore, the difference in refractive index between adjacent refractive functional layers is 0.2-2.0, preferably 0.2-1.0, and particularly preferably 0.3-1.0.

[0038] Furthermore, the preparation method further comprises: processing the color conversion film structure by dry etching to form at least one color conversion unit, wherein the radial dimension of the color conversion unit is 0.1-10 μm.

[0039] Furthermore, the color conversion film layer structure has a thickness of 2-3 μm.

[0040] Furthermore, the surface of the color conversion film structure is continuous and flat.

[0041] Another aspect of the present invention provides a method for improving the light absorption efficiency of a color micro-display device, comprising:

[0042] The color conversion film layer structure for improving light absorption efficiency is set on the light-emitting side of the self-luminous pixel point, or the color conversion film layer structure for improving light absorption efficiency is prepared on the light-emitting side of the self-luminous pixel point using the preparation method of the color conversion film layer structure for improving light absorption efficiency.

[0043] Furthermore, the method further comprises: processing the color conversion film structure by dry etching to form at least one color conversion unit that matches the self-luminous pixel.

[0044] Furthermore, the radial dimension of the color conversion unit is 0.1-10 μm.

[0045] Furthermore, the self-luminous pixel is a micro light emitting diode, and the radial size of the micro light emitting diode is 0.1-10 μm.

[0046] Furthermore, the method further comprises: manufacturing a barrier layer on the color conversion film layer structure, and laminating the barrier layer on the color conversion film layer structure along the selected direction.

[0047] Specifically, the barrier layer can be produced by atomic layer deposition (ALD), plasma enhanced chemical vapor deposition (PECVD), optical coating, metal organic chemical vapor deposition (MOCVD), magnetron sputtering, evaporation and the like. More specifically, the growth temperature of the barrier layer is 30°C-150°C, preferably 30°C-70°C, and the growth atmosphere is vacuum or a protective gas atmosphere such as N2 and Ar.

[0048] Furthermore, the thickness of the barrier layer is on a micro-nano scale.

[0049] Furthermore, the thickness of the barrier layer is 20-200 nm.

[0050] Furthermore, the material of the barrier layer includes any one of Al2O3, SiO2, ZrO, and AgO, or a combination of two or more thereof.

[0051] Another aspect of the present invention provides a color micro display device, comprising: a plurality of self-luminous pixels and the color conversion film structure for improving light absorption efficiency, wherein the color conversion film structure is covered on the light-emitting side of the self-luminous pixels.

[0052] Furthermore, the self-luminous pixel is a micro light emitting diode, and the radial size of the micro light emitting diode is 0.1-10 μm.

[0053] Furthermore, the color micro-display device further includes: a barrier layer, wherein the barrier layer is stacked on the color conversion film layer structure along the selected direction.

[0054] Furthermore, the thickness of the barrier layer is on a micro-nano scale.

[0055] Furthermore, the thickness of the barrier layer is 20-200 nm.

[0056] Furthermore, the material of the barrier layer includes any one of Al2O3, SiO2, ZrO, and AgO, or a combination of two or more thereof.

[0057] Compared with the prior art, the advantages of the present invention include:

[0058] 1) The color conversion film structure provided by the present invention changes the light output angle and realizes the light source surface scattering phenomenon by introducing multiple refractive functional layers. The arrangement of the refractive functional layers can be in any pattern (ABABAB / ABCBAC / CBABCAB...It should be noted that ABC corresponds to a refractive functional layer respectively).

[0059] 2) The refractive functional layer in the color conversion film structure provided by the present invention is a metal oxide or an inorganic non-metallic oxide, both of which have a dense structure and a protective effect on QDs, thereby greatly reducing the problem of quantum dot quenching caused by the low water-oxygen barrier absorption in the glue system (the main glue body is PMMA or PS, etc., which have poor water-like heat resistance).

[0060] 3) The color conversion film structure provided by the present invention can effectively improve the light absorption efficiency by introducing a multi-layer refractive functional layer, and its lifespan is much longer than that of the traditional film structure.

[0061] 4) The color conversion film layer structure provided by the present invention is a multi-layer structure with uniform thickness in cross section, which can effectively ensure the uniformity of the etching rate of each layer during dry etching, thereby greatly avoiding the problem of uncontrollable device morphology caused by inconsistent etching rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 This is a schematic structural diagram of a color display device in the prior art;

[0063] Figure 2 It is a structural schematic diagram of another color display device in the prior art;

[0064] Figure 3a 1 is a schematic structural diagram of a color micro-display device provided in a typical embodiment of the present invention;

[0065] Figure 3b 1 is a schematic structural diagram of a color micro-display device provided in a typical embodiment of the present invention;

[0066] Figure 4This is a schematic structural diagram of a color conversion film layer structure and a self-luminous pixel in a color micro-display device provided in a typical embodiment of the present invention;

[0067] Figure 5 1 is a schematic structural diagram of a color conversion film layer structure in Example 1 of the present invention;

[0068] Figure 6 2 is a schematic structural diagram of a color conversion film layer structure in Example 2 of the present invention;

[0069] Figure 7 1 is a schematic structural diagram of a color conversion film layer structure in Example 3 of the present invention;

[0070] Figure 8 Schematic diagram of a color conversion film structure in Example 4 of the present invention;

[0071] Figure 9 It is a schematic diagram of the optical path of light passing through a refractive medium layer. DETAILED DESCRIPTION

[0072] In view of the shortcomings of the prior art, the inventors of this case, after long-term research and extensive practice, have proposed the technical solution of the present invention. This technical solution, its implementation process, and principles are further explained below with reference to the accompanying drawings and specific implementation examples. Unless otherwise specified, the vapor deposition, optical coating, sputtering, evaporation equipment and processes, and spin coating, spray coating, screen printing, inkjet printing, and other film-forming equipment and processes used in the embodiments of the present invention are all known to those skilled in the art.

[0073] The present invention provides a color conversion film layer structure for improving light absorption efficiency. The color conversion film layer changes the original straight light path into a divergent surface light source through a partitioned light conversion film layer, thereby solving the problem of blue light overflow and improving the absorption efficiency of blue light. At the same time, it also solves the problem of the life of the color conversion film layer structure and the color micro-display device.

[0074] See also Figure 3a and Figure 3bIn a typical embodiment, a color micro-display device includes a driving substrate 100, a light-emitting layer 200, a color conversion layer 300, and a barrier layer 400, which are sequentially stacked along a selected direction. The light-emitting layer 200 includes a plurality of self-luminous pixels 210 and a filling layer 220 disposed on the driving substrate 100. The filling layer 220 is disposed around the plurality of self-luminous pixels 210. The color conversion layer 300 includes a first color conversion film layer structure 310, a second color conversion film layer structure 320, a third color conversion film layer structure 330, and a barrier layer 400. The isolation layer 340, the first color conversion film layer structure 310, the second color conversion film layer structure 320, and the third color conversion film layer structure 330 are respectively covered on a self-luminous pixel 210. The self-luminous pixel 210 can be superimposed with the first color conversion film layer structure 310, the second color conversion film layer structure 320, or the third color conversion film layer structure 330 to emit light with a specified wavelength. The isolation layer 340 is arranged around the first color conversion film layer structure 310, the second color conversion film layer structure 320, and the third color conversion film layer structure 330.

[0075] Specifically, the driving substrate 100 may be a thin film transistor, such as a silicon-based TFT or CMOS.

[0076] Specifically, the self-luminous pixel 210 can be a micro-light emitting diode or a micro-organic light emitting diode, i.e., a Micro-LED. Specifically, a Micro-LED is formed based on inorganic semiconductor materials, where the inorganic semiconductor materials can be gallium nitride, aluminum gallium nitride, gallium arsenide, aluminum gallium indium phosphide, etc. A Micro-organic light emitting diode is formed based on organic materials, where the organic materials can be small molecules, polymers, phosphorescent materials, etc.

[0077] Specifically, the self-luminous pixel 210 can provide initial light emission having a first wavelength, which can be monochromatic light, such as ultraviolet, blue, or green. If the initial light emission includes light of a wavelength required for the micro-display to be implemented, the color conversion film layer structure (material) corresponding to the wavelength can be omitted. For example, if the initial light emission of the display is blue, the corresponding blue color conversion film layer structure is not required. If the initial light emission of the display is ultraviolet light, a blue color conversion film layer structure is required to convert the blue light.

[0078] Specifically, a plurality of self-luminous pixel points 210 may be provided, and the plurality of self-luminous pixel points 210 are distributed in a first area on the surface of the driving substrate 100, and the filling layer 220 is distributed in a second area on the surface of the driving substrate 100. The second area is adjacent to the first area, and the first area may be considered as a luminous area, wherein the plurality of self-luminous pixel points 210 may be distributed in a graphical array.

[0079] Specifically, the pixel pitch size of the self-luminous pixel 210 is 1100 μm, and the pixel resolution of the self-luminous pixel 210 can be flexibly set, such as VGA (640*480), XGA (1024*768), FHD (1920*1080), etc.

[0080] Specifically, the thickness of the self-luminous pixel 210 and the filling layer 220 can be the same, so that the entire surface of the light-emitting layer 200 is continuous and flat. Specifically, the filling layer 220 is made of an insulating material, such as silicon oxide.

[0081] Specifically, the first color conversion film layer structure 310 can be a red light conversion structure, the second color conversion film layer structure 320 can be a green light conversion structure, and the third color conversion film layer structure 330 can be a blue light conversion structure. As mentioned above, when the initial light provided by the self-luminous pixel point 210 is blue light, the third color conversion film layer structure 330 can be omitted.

[0082] Specifically, the structures of the first color conversion film layer structure 310 , the second color conversion film layer structure 320 , and the third color conversion film layer structure 330 may be the same. Therefore, they are collectively referred to as color conversion film layer structures below to explain and illustrate their specific structures.

[0083] See also Figure 4 The color conversion film layer structure includes at least one wavelength conversion layer 301 with a micro-nano scale and at least two refractive functional layers 500 with a micro-nano scale stacked along a selected direction. The difference between the refractive index of the refractive functional layer 500 and the refractive index of the adjacent wavelength conversion layer 301 is greater than 0.2, and the difference between the refractive index of adjacent refractive functional layers 500 is greater than 0.2.

[0084] Specifically, the difference in refractive index between adjacent refractive functional layers 500 may be 0.2-2.0, preferably 0.2-1.0, and particularly preferably 0.3-1.0.

[0085] Specifically, the wavelength conversion layer 301 can superimpose the initial light of the first wavelength emitted by the self-luminous pixel 210 to emit light of a specified wavelength. For example, the wavelength conversion layer in the first color conversion film layer structure 310 can superimpose the initial light of the self-luminous pixel 210 to emit red light, the wavelength conversion layer in the second color conversion film layer structure 320 can superimpose the initial light of the self-luminous pixel 210 to emit green light, and the wavelength conversion layer in the third color conversion film layer structure 330 can superimpose the initial light of the self-luminous pixel 210 to emit blue light; see Figure 9When light passes through the refractive functional layer 500, whose refractive index is greater than that of the wavelength conversion layer and whose difference in at least two refractive indices is greater than or equal to 0.2, it is refracted, so that the optical path of the light is changed, thereby changing the angle of the light output and realizing the scattering phenomenon of the light output surface.

[0086] Specifically, the color conversion film layer structure includes at least two wavelength conversion layers 301 and at least two refractive functional layers 500 stacked along a selected direction.

[0087] It should be noted that there can be n different refractive functional layers (n ≥ 1) between any two wavelength conversion layers. Only when there is a refractive index difference between the n different refractive functional layers can the optical path be increased as much as possible. The larger the refractive index difference, the larger the refraction angle, and the greater the increase in optical path. The refractive index difference between adjacent refractive functional layers is between 0.2-2.0, the larger the better. However, because high-refractive index materials are limited, the refractive index difference is generally preferred to be between 0.3-1.0.

[0088] The thicknesses of any two wavelength conversion layers 301 can be the same or different, and the thicknesses of any two refractive functional layers 500 can also be the same or different. Specifically, the thickness of each wavelength conversion layer is less than or equal to 300 nm, for example, 100-300 nm. The thickness of each refractive functional layer is less than or equal to 100 nm, for example, 20-100 nm, and particularly preferably 20-30 nm. Specifically, the thickness of the color conversion film structure along a selected direction is 2-3 μm.

[0089] Specifically, wavelength conversion layer 301 is a dense film layer formed of a photoconversion material, wherein the photoconversion material can be a quantum dot glue mixture formed by mutually dissolving and uniformly dispersing quantum dots (QDs) and photoresist. The particle size of the quantum dots is 1-50 nm, and the content of the quantum dots in the photoconversion material is 30 wt%-80 wt%, for example, 30 wt%, 40 wt%, 45 wt%, 65 wt%, 80 wt%, etc. Specifically, the quantum dots include one or a combination of two or more of CdSe, CdS, CdZnSe, CdZnS, CdZnSeS, ZnSeS, ZnSe, CuInS, CuInSe, InP, InZnP, and perovskite quantum dots. The photoresist can be a transparent material known to those skilled in the art, such as polymethyl methacrylate (PMMA) and polystyrene (PS).

[0090] Specifically, the refractive functional layer 500 is a dense film layer formed of a refractive functional material. The refractive functional material includes a metal oxide or an inorganic non-metallic oxide. Both metal oxides and inorganic non-metallic oxides have a dense structure and protect the quantum dots, significantly reducing quantum dot quenching caused by the low water-oxygen barrier absorption in the glue system. Specifically, the refractive functional material includes any one of TiO2, ZrO, Al2O3, SiO2, ZnO, SiO, MgF, SiO2, Ti3O5, Ti2O3, TiO, Ta2O5, HfO2, Nb2O5, MgO, Y2O3, AlF3, ZnS, and ZnSe, or a combination of two or more.

[0091] It should be noted that the wavelength conversion layer and each functional refractive layer included in the color conversion film layer structure of the present invention have uniform thickness. The color conversion film layer structure is a multilayer structure with uniform cross-section thickness. When the color conversion film layer is dry-etched to form a pattern, the uniformity of the etching rate of each structural layer is guaranteed, which greatly avoids the problem of uncontrollable device morphology caused by inconsistent etching rate.

[0092] The inventors of this case have found that the corresponding relationship between the thickness x of the refractive functional layer and the blue light reflectivity y is:

[0093] y=-0.0014x 2 +0.6813x+4 (the refractive layer is a single layer)

[0094] y=-1E -05 x 3 +0.0043x 2 +0.078x+26.714△n+12.51 (the refractive functional layer is a multi-layer superposition, △n is the difference in refractive index between the two refractive functional layers).

[0095] The refractive index of the functional refractive layer used in the present invention and the corresponding light transmission band are shown in Table 1.

[0096] Table 1 shows the refractive index of each functional refractive layer material and its corresponding light transmission band

[0097] name Molecular formula Refractive index Transmittance band magnesium fluoride <![CDATA[MgF2]]> 1.38 160-8000nm Silicon dioxide <![CDATA[SiO2]]> 1.46 200-2000nm Alumina <![CDATA[Al2O3]]> 163 200-5000nm Silicon monoxide <![CDATA[SiO2]]> 155 800-8000nm Titanium dioxide <![CDATA[TiO2]]> 2.35 400-12000nm Titanium pentoxide <![CDATA[Ti2O5]]> 2.35 400-12000nm Titanium trioxide <![CDATA[Ti2O3]]> 2.35 400-12000nm Titanium monoxide TiO 2.35 400-12000nm Tantalum pentoxide <![CDATA[Ta2O5]]> 2.1 350-7000nm Hafnium oxide <![CDATA[HfO2]]> 1.95 230-7000nm Zirconia <![CDATA[ZrO2]]> 2.05 250-7000nm Niobium oxide <![CDATA[Nb2O5]]> 2.3 350-9000nm magnesium oxide MgO 1.7 200-8000nm zinc oxide ZnO 2 400-16000nm Yttrium oxide <![CDATA[Y2O3]]> 1.8 250-8000nm Cerium oxide <![CDATA[CeO2]]> 2.2 400-11000nm Cerium fluoride <![CDATA[CeF3]]> 1.63 300-5000nm Lanthanum fluoride <![CDATA[LaF3]]> 1.58 220-14000nm Yttrium fluoride <![CDATA[YF3]]> 1.55 200-14000nm Barium fluoride <![CDATA[BaF2]]> 1.4 220-15000nm Aluminum fluoride <![CDATA[AIF3]]> 1.35 200-8000nm cryolite <![CDATA[Na3AlF6]]> 1.33 200-14000nm Cone Cryolite <![CDATA[Na5Al3F 14 ]]> 1.33 200-14000nm zinc sulfide ZnS 2.4 400-1000nm zinc selenide ZnSe 2.58 600-15000nm

[0098] Specifically, the surfaces of the first, second, and third color-conversion film layers 310, 320, and 330 are continuous and flat. The thicknesses of the first, second, and third color-conversion film layers 310, 320, and 330 are the same as those of the isolation layer 340, ensuring a continuous and flat surface for the entire color-conversion layer 300. This ensures seamless adhesion between the color-conversion layer 300 and the barrier layer 400. Specifically, the isolation layer 340 is made of an insulating material, such as silicon oxide.

[0099] Specifically, the material of the barrier layer 400 includes Al 2 O 3 , SiO 2 , ZrO, AgO, etc., and the thickness of the barrier layer 400 is 20-200 nm.

[0100] In a more specific embodiment, a method for preparing a color micro-display device may include the following steps:

[0101] 1) Provide a display panel, which includes a driving substrate 100 and a light-emitting layer 200 disposed on a surface of the driving substrate 100. The structures and selection of the driving substrate 100 and the light-emitting layer 200 can be referred to above.

[0102] 2) A first color conversion film structure 310 is formed on the surface of the light-emitting layer 200 , and the first color conversion film structure 310 covers a portion of the self-luminous pixels 210 .

[0103] Step 2 may specifically include:

[0104] 2.1) Forming at least one wavelength conversion layer 301 having a micro-nano scale and at least two refractive functional layers 500 having a micro-nano scale along a selected direction on the surface of the light-emitting layer 200, and stacking the at least one wavelength conversion layer 301 and the at least two refractive functional layers 500 in sequence along the selected direction, wherein the difference between the refractive index of the refractive functional layer 500 and the refractive index of the wavelength conversion layer 301 is greater than or equal to 0.2, and the difference between the refractive indices of adjacent refractive functional layers 500 is greater than or equal to 0.2, thereby forming a first color conversion layer.

[0105] Specifically, step 2.1) includes:

[0106] A light conversion material is spin-coated on the surface of the light-emitting layer 200 by spin coating or other methods. The thickness of the light conversion material is adjusted by controlling the rotation speed (e.g., 1500 rpm / min) (the higher the speed, the thinner the film). The light conversion material is then hardened at 60° C. to 100° C. for 1 to 30 minutes to form a wavelength conversion layer with a thickness of 100 to 300 nm.

[0107] The refractive functional materials are grown by atomic layer deposition (ALD), plasma enhanced chemical vapor deposition (PECVD), optical coating, metal organic chemical vapor deposition (MOCVD), magnetron sputtering, evaporation, etc., and the growth rate is controlled to Growing a refractive functional layer with a thickness of 20-100 nm, preferably 20-30 nm;

[0108] The refractive functional material is changed in a selected order during the growth process, and at least one of the above processes is repeated more than once, thereby obtaining a first color conversion layer.

[0109] The difference in refractive index between the refractive functional layer 500 and the wavelength conversion layer 301 may be 0.2-2.0, preferably 0.2-1.0, and particularly preferably 0.3-1.0. The difference in refractive index between adjacent refractive functional layers 500 may be 0.2-2.0, preferably 0.2-1.0, and particularly preferably 0.3-1.0.

[0110] The refractive functional layer obtained by the present invention by atomic layer deposition and other methods has a uniform thickness, is dense, and is pure. Because the film layer is dense, it also has a certain barrier effect on water and oxygen, and it also acts as a passivation layer. By growing multiple layers of refractive functional layers with different refractive indices (the refractive index is greater than the refractive index of the wavelength conversion layer), the optical path can be adjusted from the original straight line (2-3um) to a broken line, thereby greatly improving the optical path, while also increasing the light output rate, improving the life and optical performance of the device. This is because when light is obliquely incident from one medium to another, the propagation direction changes, causing the light to be deflected at the junction of different media. Through this refraction method, the original single straight optical path is converted into a multi-fold path, thereby improving the optical path and light absorption efficiency (because each layer is a flat film layer, which will purely be in the mirror reflection effect, the Ag mirror structure is used to realize the light path return and avoid the mirror reflection phenomenon).

[0111] 2.2) A first mask is set on the first color conversion layer, and the first mask covers a portion of the first color conversion layer. It should be noted that the first mask corresponds to a portion of the self-luminous pixel points 210. The correspondence means that the shape, area, and distribution pattern of the first mask are the same as the shape, area, and distribution pattern of the portion of the self-luminous pixel points 210.

[0112] 2.3) The first color conversion layer not covered by the first mask is removed by dry etching. The remaining portion of the first color conversion layer is correspondingly disposed above some of the self-luminous pixels 210 , thereby forming a first color conversion film structure 310 .

[0113] Specifically, dry etching includes physical etching, chemical etching or a combination of physical etching and chemical etching, wherein physical etching can be ion beam etching, and the typical etching gas used in ion beam etching can be argon, etc., and chemical etching can be plasma etching, and the typical etching gas used in plasma etching can be sulfur hexafluoride, carbon tetrafluoride, etc.; the combination of physical etching and chemical etching can be reactive ion etching, and the typical etching gas used in reactive ion etching can be chlorine, boron trichloride, sulfur hexafluoride, carbon tetrafluoride, argon, etc.

[0114] 3) A second color conversion film structure 320 is fabricated on the surface of the light-emitting layer 200 , and the second color conversion film structure 320 covers another portion of the self-luminous pixels 210 .

[0115] Specifically, step 3) includes:

[0116] 3.1) Referring to step 2.1), a second color conversion layer is formed on the surface of the light-emitting layer 200 .

[0117] 3.2) A second mask is set on the second color conversion layer, and the second mask covers a portion of the second color conversion layer. It should be noted that the second mask corresponds to another part of the self-luminous pixel points 210. The correspondence means that the shape, area, and distribution pattern of the second mask are the same as the shape, area, and distribution pattern of the other part of the self-luminous pixel points 210, and there is no overlapping area between the second mask and the orthographic projection area of ​​the first mask.

[0118] 3.3) The second color conversion layer not covered by the second mask is removed by dry etching. The remaining portion of the second color conversion layer is correspondingly disposed above another portion of the self-luminous pixels 210 , thereby forming a second color conversion film structure 320 .

[0119] 4) Referring to step 3), a third color conversion film structure 330 is formed.

[0120] It should be noted that the method of dry etching the color conversion layer can refer to CN113990999A. Of course, the present invention can also first set an etching barrier layer on the surface of the light-emitting layer. When manufacturing the second color conversion film layer structure 320, the first mask can also be retained to protect the first color conversion film layer structure 310 with reference to CN113990999A. The first color conversion film layer structure 310, the second color conversion film layer structure 320 or the third color conversion film layer structure 330 are the aforementioned color conversion units.

[0121] The mask used in the present invention includes a semiconductor mask, a photoresist mask or a metal mask, wherein the material of the semiconductor mask can be silicon dioxide, silicon nitride or aluminum oxide, etc., and the metal mask can be a plurality of metal layers stacked together, and the material of the metal layer includes cadmium, aluminum, nickel, gold, titanium or platinum, etc.

[0122] 5) An isolation material is provided on the light-emitting layer 200 to form an isolation layer 340, and the isolation layer 340 is filled between the first color conversion film layer structure 310, the second color conversion film layer structure 320, and the third color conversion film layer structure 320. The thickness of the first color conversion film layer structure 310, the second color conversion film layer structure 320, the third color conversion film layer structure 320, and the isolation layer 340 are the same, thereby forming a color conversion layer 300, and the surface of the formed color conversion layer 300 is continuous and flat.

[0123] 6) A barrier layer 400 is formed on the color conversion layer 300 .

[0124] Specifically, the barrier layer can be produced by atomic layer deposition (ALD), plasma enhanced chemical vapor deposition (PECVD), optical coating, metal organic chemical vapor deposition (MOCVD), magnetron sputtering, evaporation and other methods. More specifically, the growth temperature of the barrier layer is 30°C-150°C, preferably 30°C-70°C, and the growth atmosphere is vacuum or protective gas atmosphere such as N2 and Ar.

[0125] Of course, the process may also include a step of packaging the formed color micro display device, which is not particularly limited here.

[0126] Example 1

[0127] See also Figure 3a 、 Figure 3b and Figure 5 In this embodiment, the self-luminous pixels in a color micro-display device are blue Micro-LEDs. The first color conversion film layer structure 310 and the second color conversion film layer structure 320 include multiple color conversion units stacked along a selected direction. Each color conversion unit includes a wavelength conversion layer 301, a first refractive functional layer 501, and a second refractive functional layer 502 stacked in sequence along the selected direction. The wavelength conversion layer 301 has a thickness of 300 nm, and the first and second refractive functional layers 501 and 502 each have a thickness of 100 nm. The first refractive functional layer 501 is a SiO2 layer, and the second refractive functional layer 502 is a Y2O3 layer.

[0128] Example 2

[0129] See also Figure 3a 、 Figure 3b and Figure 6In this embodiment, the self-luminous pixel in a color micro-display device is a blue light Micro-LED. The first color conversion film layer structure 310 and the second color conversion film layer structure 320 include multiple color conversion units stacked along a selected direction. Each color conversion unit includes a first refractive functional layer 501, a wavelength conversion layer 301, and a second refractive functional layer 502 stacked in sequence along the selected direction. The wavelength conversion layer 301 has a thickness of 150 nm, and the first refractive functional layer 501 and the second refractive functional layer 502 are both 40 nm thick. The first refractive functional layer 501 is a SiO2 layer, and the second refractive functional layer 502 is a HfO2 layer.

[0130] Example 3

[0131] See also Figure 3a 、 Figure 3b and Figure 7 In this embodiment, the self-luminous pixel in a color micro-display device is a blue Micro-LED. The first color conversion film layer structure 310 and the second color conversion film layer structure 320 include multiple color conversion units stacked along a selected direction. Each color conversion unit includes a wavelength conversion layer 301, a first refractive functional layer 501, a second refractive functional layer 502, and a third refractive functional layer 503 stacked in sequence along the selected direction. The wavelength conversion layer 301 has a thickness of 100 nm, and the first, second, and third refractive functional layers 501, 502, 503 each have a thickness of 30 nm. The first refractive functional layer 501 is a SiO2 layer, the second refractive functional layer 502 is a HfO2 layer, and the third refractive functional layer 503 is a TiO2 layer.

[0132] Example 4

[0133] See also Figure 3a 、 Figure 3b and Figure 8 In this embodiment, the self-luminous pixels in a color micro-display device are blue micro-LEDs. The first color conversion film layer structure 310 and the second color conversion film layer structure 320 include a plurality of color conversion units stacked along a selected direction. Each color conversion unit includes a first refractive functional layer 501, a wavelength conversion layer 301, a second refractive functional layer 502, and a third refractive functional layer 503 stacked in sequence along the selected direction. The wavelength conversion layer 301 has a thickness of 120 nm, and the first, second, and third refractive functional layers 501, 502, 503 each have a thickness of 20 nm. The refractive index of the first refractive functional layer 501 is smaller than that of the second refractive functional layer 502 and the third refractive functional layer 503. The first refractive functional layer 501 is a SiO2 layer, the second refractive functional layer 502 is a Y2O3 layer, and the third refractive functional layer 503 is a CeO2 layer.

[0134] Comparative Example 1

[0135] See also Figure 2 The structure of the color micro display device in Comparative Example 1 is basically the same as that in Example 1, except that: in Comparative Example 1, TiO2 nanoparticles are doped into the wavelength conversion layer, and the particle size of the TiO2 nanoparticles is 150 nm.

[0136] Comparative Example 2

[0137] See also Figure 2 The structure of the color microdisplay device in Comparative Example 2 is essentially the same as that in Example 1, except that SiO2 nanoparticles and TiO2 nanoparticles are incorporated into the wavelength conversion layer. The TiO2 nanoparticles have a particle size of 150 nm, and the SiO2 nanoparticles have a particle size of 200 nm.

[0138] Comparative Example 3

[0139] See also Figure 1 The structure of the color micro display device in Comparative Example 3 is substantially the same as that in Example 1, except that: Comparative Example 3 does not perform any doping treatment on the wavelength conversion layer.

[0140] Performance tests were performed on the color micro-display devices in Examples 1 to 4 and Comparative Examples 1 to 3, respectively. The equipment and methods used in the tests are known to those skilled in the art. The test results are shown in Table 1.

[0141] Table 1 shows the performance test results of the color micro-display devices in Examples 1 to 4 and Comparative Examples 1 to 3.

[0142]

[0143] As can be seen from the test results in Table 1, compared with the traditional method of using inorganic nanoparticles as light diffusion materials, although this method can obtain a uniform film thickness to obtain a color conversion layer and realize the preparation of smaller pixels (Micro-LED, but due to the precision limitations of the photoresist, it cannot realize micro-nanoscale pixels. When the etching method is used to process it, the etching rate is greatly affected by the disorderly distribution of the diffusion particles in the film layer. In addition, the diffusion particles need to be surface modified, and the modifier damages the QDs, which in turn affects the life of the color conversion layer.

[0144] The color conversion film structure provided by the present invention changes the light emission angle and realizes the light source surface scattering phenomenon by introducing multiple refractive functional layers. The arrangement of the refractive functional layers can be in any pattern (ABABAB / ABCBAC / CBABCAB...It should be noted that ABC corresponds to a refractive functional layer respectively).

[0145] The refractive functional layer in the color conversion film structure provided by the present invention is a metal oxide or an inorganic non-metallic oxide, both of which have a dense structure and a protective effect on QDs, thereby greatly reducing the problem of quantum dot quenching caused by low water-oxygen barrier absorption in the glue system (the main glue body is PMMA or PS, etc., which have poor water-like heat resistance).

[0146] The color conversion film structure provided by the present invention can effectively improve light absorption efficiency by introducing a multi-layer refractive functional layer, and its lifespan is much longer than that of a traditional film structure.

[0147] The color conversion film layer structure provided by the present invention is a multilayer structure with uniform thickness in cross section, which can effectively ensure the uniformity of the etching rate of each layer when dry etching is performed thereon, thereby greatly avoiding the problem of uncontrollable device morphology caused by inconsistent etching rate.

[0148] It should be understood that the above embodiments are merely illustrative of the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent variations or modifications made in accordance with the spirit and substance of the present invention are intended to be encompassed within the scope of protection of the present invention.

Claims

1. A color conversion film structure for improving light absorption efficiency, characterized in that: include: At least one wavelength conversion layer and at least two refractive functional layers, the wavelength conversion layer and the refractive functional layer are stacked, wherein the refractive functional layer is a dense film layer formed of a refractive functional material, the refractive index of the refractive functional layer is greater than the refractive index of the wavelength conversion layer, the difference between the refractive index of the refractive functional layer and the refractive index of the adjacent wavelength conversion layer is greater than or equal to 0.2, and the difference between the refractive indices of two adjacent refractive functional layers is greater than or equal to 0.2, the thickness of each wavelength conversion layer is 100-300nm, and the thickness of each refractive functional layer is 20-100nm.

2. The color conversion film structure according to claim 1, wherein: The wavelength conversion layer is a dense film layer formed of a light conversion material. The light conversion material includes quantum dots. The particle size of the quantum dots is 1-50 nm. The content of the quantum dots in the light conversion material is 30 wt %-80 wt %.

3. The color conversion film structure according to claim 1, wherein: The refractive functional material includes any one or a combination of two or more of TiO2, ZrO, Al2O3, SiO2, ZnO, SiO, MgF, SiO2, Ti3O5, Ti2O3, TiO, Ta2O5, HfO2, Nb2O5, MgO, Y2O3, AlF3, ZnS, and ZnSe.

4. The color conversion film structure according to claim 1, characterized in that: include: A plurality of the wavelength conversion layers and the plurality of the refractive functional layers are stacked, and two or more refractive functional layers are arranged between any two of the wavelength conversion layers. Alternatively, the wavelength conversion layers and the refractive functional layers are alternately arranged in sequence, and the thicknesses of any two of the wavelength conversion layers are the same or different, and the thicknesses of any two of the refractive functional layers are the same or different.

5. The color conversion film structure according to claim 1, wherein: The difference in refractive index between two adjacent refractive functional layers is 0.2-2.

0.

6. The color conversion film structure according to claim 1, wherein: The thickness of the color conversion film layer structure is 2-3 μm.

7. A method for preparing a color conversion film structure with improved light absorption efficiency, characterized in that: include: At least one wavelength conversion layer and at least two refractive functional layers are manufactured, wherein the thickness of each wavelength conversion layer is 100-300 nm, and the thickness of each refractive functional layer is 20-100 nm, and the at least one wavelength conversion layer and the at least two refractive functional layers are stacked in sequence, wherein the refractive functional layer is a dense film layer formed of a refractive functional material, the refractive index of the refractive functional layer is greater than the refractive index of the wavelength conversion layer, the difference between the refractive index of the refractive functional layer and the refractive index of the adjacent wavelength conversion layer is greater than or equal to 0.2, and the difference between the refractive indices of adjacent refractive functional layers is greater than or equal to 0.2, thereby forming the color conversion film layer structure.

8. The preparation method according to claim 7, wherein include: The wavelength conversion layer is formed by forming a dense film layer with a light conversion material. The light conversion material includes quantum dots. The particle size of the quantum dots is 1-50 nm. The content of the quantum dots in the light conversion material is 30 wt %-80 wt %.

9. The preparation method according to claim 7, characterized in that include: The refractive functional material is formed into a dense film layer by any one of atomic layer deposition, plasma enhanced chemical vapor deposition, optical coating, metal organic compound chemical vapor deposition, magnetron sputtering, and evaporation vapor deposition, thereby forming a refractive functional layer. The refractive functional material includes any one of TiO2, ZrO, Al2O3, SiO2, ZnO, SiO, MgF, SiO2, Ti3O5, Ti2O3, TiO, Ta2O5, HfO2, Nb2O5, MgO, Y2O3, AlF3, ZnS, and ZnSe, or a combination of two or more thereof.

10. The preparation method according to claim 7, characterized in that The preparation method further comprises: etching the color conversion film layer structure by dry etching to form at least one color conversion unit, wherein the radial dimension of the color conversion unit is 0.1-10 μm.

11. A color micro display device, characterized in that: include: A plurality of self-luminous pixels and a color conversion film structure for improving light absorption efficiency according to any one of claims 1 to 6, wherein the color conversion film structure is covered on the light-emitting side of the self-luminous pixels.

12. The color micro-display device according to claim 11, characterized in that: The self-luminous pixel is a micro light emitting diode, and the size of the micro light emitting diode is 0.1-10 μm.

13. The color micro-display device according to claim 11, characterized in that: The color micro-display device further includes a barrier layer, which is stacked on the color conversion film structure. The thickness of the barrier layer is 20-200 nm, and the material of the barrier layer includes any one of Al2O3, SiO2, ZrO, and AgO, or a combination of two or more.

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