WO2022246690A1 - 显示面板、其制备方法和显示装置 - Google Patents

显示面板、其制备方法和显示装置 Download PDF

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Publication number
WO2022246690A1
WO2022246690A1 PCT/CN2021/096070 CN2021096070W WO2022246690A1 WO 2022246690 A1 WO2022246690 A1 WO 2022246690A1 CN 2021096070 W CN2021096070 W CN 2021096070W WO 2022246690 A1 WO2022246690 A1 WO 2022246690A1
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Prior art keywords
layer
light
pixel
sub
wavelength conversion
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PCT/CN2021/096070
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English (en)
French (fr)
Inventor
李伟
张宜驰
张粲
王灿
袁丽君
丛宁
牛晋飞
张晶晶
玄明花
Original Assignee
京东方科技集团股份有限公司
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Application filed by 京东方科技集团股份有限公司 filed Critical 京东方科技集团股份有限公司
Priority to CN202180001282.5A priority Critical patent/CN115918293A/zh
Priority to EP21942271.4A priority patent/EP4207298A4/en
Priority to PCT/CN2021/096070 priority patent/WO2022246690A1/zh
Priority to US17/772,595 priority patent/US20230141443A1/en
Publication of WO2022246690A1 publication Critical patent/WO2022246690A1/zh

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/30—Devices specially adapted for multicolour light emission
    • H10K59/38—Devices specially adapted for multicolour light emission comprising colour filters or colour changing media [CCM]
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/10—OLED displays
    • H10K59/12—Active-matrix OLED [AMOLED] displays
    • H10K59/1201—Manufacture or treatment
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/10—OLED displays
    • H10K59/12—Active-matrix OLED [AMOLED] displays
    • H10K59/122—Pixel-defining structures or layers, e.g. banks
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2102/00—Constructional details relating to the organic devices covered by this subclass
    • H10K2102/301—Details of OLEDs
    • H10K2102/302—Details of OLEDs of OLED structures
    • H10K2102/3023—Direction of light emission
    • H10K2102/3026—Top emission
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2102/00—Constructional details relating to the organic devices covered by this subclass
    • H10K2102/301—Details of OLEDs
    • H10K2102/351—Thickness
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H10K59/875—Arrangements for extracting light from the devices
    • H10K59/879—Arrangements for extracting light from the devices comprising refractive means, e.g. lenses

Definitions

  • the present disclosure relates to the display field, and more specifically relates to a display panel, a manufacturing method thereof, and a display device.
  • OLED Organic light-emitting display
  • FMM fine metal mask
  • the RGB type of inkjet printing RGB OLED is a potential technology for large-size OLEDs
  • the color gamut value is not high enough due to the limitations of the research and development of solution-based OLED materials.
  • the other is to use monochromatic OLED as the backlight light-emitting unit to cooperate with color film to realize color display, which can be called backlight-color film type. Since the entire surface of an open mask can be used for vapor deposition, the method of white backlight and color film has become one of the mainstream technologies for large-size OLEDs.
  • the white backlight-color film technology the color film plays the role of filtering out light waves with wavelengths other than the desired color in white light.
  • the color gamut of the color filter directly limits the color gamut of large-size OLED products.
  • a technology that uses a wavelength conversion element to change the color of light emitted by a monochrome OLED to achieve color display has emerged.
  • the technology of combining blue OLED and QD (quantum dots) has been proposed in the related art, using blue OLED as light source, and cooperating with QD to down-convert blue light into red light and green light to realize color display, which is called QD-OLED.
  • the present disclosure provides a display panel, including:
  • the light-emitting layer on the substrate substrate is the light-emitting layer on the substrate substrate.
  • the display panel includes sub-pixels arranged in an array, and the sub-pixels arranged in the array include adjacent first sub-pixels and second sub-pixels, and each of the first sub-pixels and second sub-pixels One comprising a light-emitting unit in the light-emitting layer and a wavelength conversion unit in the wavelength conversion layer, the light-emitting unit and the wavelength conversion unit are stacked and separated by the transparent spacer layer ,
  • the light-emitting units of the first sub-pixel and the second sub-pixel are separated by the first pixel-defining layer in the light-emitting layer, and the distance between the top surfaces is d2,
  • the wavelength conversion unit of the first sub-pixel is a first wavelength conversion unit and the brightness change rate of the light emitted by the light-emitting unit is ra
  • the wavelength conversion unit of the second sub-pixel is a second wavelength conversion unit and The luminance change rate of the light emitted by the light-emitting unit is rb
  • the wavelength conversion units of the first sub-pixel and the second sub-pixel are separated by a second pixel-defining layer in the wavelength conversion layer
  • the projection length of the light path passing through the transparent spacer layer on the base substrate is less than or equal to d2+d4 2 .
  • the difference between the length of the projection of the light path passing through the transparent spacer layer on the base substrate and d2+d4 2 Less than or equal to 5 ⁇ m.
  • the first pixel between defines the orthographic projection of the boundary of the layer on the base substrate, the bottom surface of the first wavelength conversion unit and the first wavelength conversion unit between the first sub-pixel and the second sub-pixel
  • the displacement of the orthographic projection of the boundary of the two-pixel defining layer on the substrate is d4 1 ,
  • the projection length of the light path passing through the transparent spacer layer on the base substrate is less than or equal to d2+d4 1 .
  • p2 p1.
  • d4 1 d4 2 .
  • the thickness of the transparent spacer layer is d1
  • the transparent spacer layer includes m sublayers stacked from bottom to top
  • the thickness and refractive index of the i-th sublayer are Li and ni respectively
  • i is 1 to m
  • i is an integer from 1 to m
  • the sub-pixels arranged in the array further include a third sub-pixel, the first sub-pixel is adjacent to the third sub-pixel, and in the third sub-pixel, there is a a light-emitting unit in the layer and a transparent color-resist unit in the wavelength conversion layer, the light-emitting unit and the transparent color-resist unit are stacked and separated by the transparent spacer layer,
  • the light-emitting units of the first sub-pixel and the third sub-pixel are separated by the first pixel-defining layer in the light-emitting layer, and the distance between the top surfaces is d5,
  • the transparent color-resist unit does not perform wavelength conversion on the light emitted by the light-emitting unit and has a brightness change rate of rc, the wavelength conversion unit of the first sub-pixel and the transparent color-resist unit of the third sub-pixel are determined by the separated by a second pixel defining layer in the wavelength conversion layer,
  • the projection length of the light path passing through the transparent spacer layer on the base substrate is less than or equal to d5+d4 3 .
  • the light emitting unit emits blue light
  • the third sub-pixel is a blue sub-pixel
  • the first sub-pixel is a red sub-pixel
  • the second sub-pixel is a green sub-pixel.
  • ra is at [110%, 180%]
  • rb is at [25%, 70%]
  • rc is at [60%, 85%].
  • the wavelength conversion unit includes quantum dots.
  • the transparent spacer layer includes a first inorganic layer, an organic layer and a second inorganic layer stacked from bottom to top.
  • the first inorganic layer is a SiNx layer
  • the second inorganic layer is a SiONx layer or an Al 2 O 3 layer
  • the organic layer is an epoxy resin layer or a polyacrylic resin layer.
  • the thickness of the organic layer is in the range of 4 to 8 ⁇ m.
  • the thickness of the organic layer is in the range of 0.3 to 0.6 ⁇ m.
  • the width of the top surface of the second pixel defining layer is smaller than the width of the bottom surface.
  • the second pixel defining layer includes a main body and a cladding layer on a sidewall of the main body.
  • the coating is an ink penetration barrier.
  • the coating includes reflective or light-absorbing materials.
  • the cladding material is metal
  • the cover layer has a lateral extension away from the main body portion at the bottom covering the surface of the transparent spacer layer.
  • said body portion has an undercut, said laterally extending portion of said cladding covering said undercut.
  • the depth of the undercut is in the range of 4 to 9 microns.
  • a color filter layer on the wavelength conversion layer is also included.
  • the present disclosure provides a method for manufacturing the above display panel, wherein the second pixel defining layer is manufactured through the following steps:
  • the coating on the top surface of the main body and the coating on the portion of the transparent spacer layer that is not shielded by the top surface of the main body are removed by dry etching, leaving the side walls of the main body and the undercuts in the undercut. the cladding.
  • the main body portion with undercuts is obtained by low-temperature curing of black material.
  • the transparent spacer layer includes an organic layer, and the organic layer is prepared by a molecular layer deposition method.
  • the present disclosure provides a display device including the above display panel or a display panel prepared according to the above method.
  • Fig. 1 (a) and (b) respectively show the schematic diagrams of the optical path of light incident at a large angle in the color filter layer and the wavelength conversion layer.
  • FIG. 2 shows a partial schematic diagram of relevant film layers of the display panel.
  • Fig. 3 shows a cross-sectional view of the sub-pixel in the dotted box in Fig. 2 at the position A-A' in the X-Z plane.
  • Fig. 4 shows a cross-sectional view at position A-A' in the X-Z plane of a pixel including three sub-pixels arranged side by side in Fig. 2 .
  • Figure 5(a)-(f) schematically illustrate the division of the layer structure.
  • FIGS 6(a)-(b) schematically illustrate the principles of the present disclosure and the structure between two adjacent sub-pixels in one embodiment.
  • Fig. 7 exemplarily shows an output angle-light intensity curve.
  • FIG. 8 shows a schematic light path in the transparent spacer layer shown in FIG. 6 .
  • FIG. 9 schematically shows the structure between two adjacent sub-pixels in one embodiment of the present disclosure.
  • FIG. 10 shows a cross section in the Y-Z plane of FIG. 2 .
  • FIG. 11 shows a schematic shape of the second pixel defining layer.
  • FIG. 12 shows a schematic diagram of a second pixel defining layer with an ink penetration prevention layer on the sidewall.
  • Fig. 13 shows a schematic diagram of a structure with an epitaxial ink permeation protection layer at the bottom.
  • Figure 14 shows a SEM photograph of the metal ink penetration barrier with undercuts and sidewalls.
  • FIG. 15 shows a schematic structural view of an embodiment of the QD-OLED display panel of the present disclosure further comprising a color filter layer.
  • Fig. 16 shows an embodiment of a light-emitting layer-related structure.
  • the inventors have found that for display panels containing wavelength conversion elements, especially QD conversion layers, the problem of cross-color between adjacent sub-pixels is a prominent problem.
  • the color filter layer is replaced with a wavelength conversion layer of similar size, so that the wavelength conversion The way to replace the filter way to achieve color light.
  • another layer of color filter can be added to further purify the wavelength-converted colored light.
  • the wavelength conversion element is sometimes referred to as a color filter (such as a QD color filter) in the related art, in the present disclosure, the color filter layer specifically refers to a layer that selectively transmits light of a specific wavelength.
  • Cross-color refers to the phenomenon that the light emitted by the light-emitting unit of one sub-pixel causes other adjacent sub-pixels to display color.
  • the sub-pixels adjacent to the light-emitting sub-pixels also emit light when they should not emit light, which is especially harmful when the adjacent sub-pixels are sub-pixels of different colors.
  • the cross-color is serious, it will obviously affect the display quality.
  • the inventors of the present disclosure unexpectedly found that in a wavelength conversion display panel, the wavelength conversion mechanism in the wavelength conversion layer has a strengthening effect on the cross-color phenomenon.
  • a conventional color filter layer even if there is backlight incident from the bottom surface from adjacent sub-pixels, due to the large incident angle, it basically advances in a straight line after entering the color filter layer, and part of it is incident on the side wall of the color filter layer It cannot be emitted from the light-emitting surface of the color filter layer, and another part may be totally reflected on the light-emitting surface and cannot be emitted.
  • FIG. 1 (a) and (b) respectively show the schematic diagrams of the optical path of light incident at a large angle in the color filter layer and the wavelength conversion layer.
  • Figure 1(a) shows the situation of the color filter layer.
  • Two adjacent sub-pixels are schematically shown in the figure.
  • two adjacent sub-pixels each include a light emitting unit 31 as a backlight layer and a color filter 51 for filtering light.
  • the light emitted by the light-emitting unit of the backlight layer of the left sub-pixel enters the bottom surface of the color filter layer of the adjacent right sub-pixel with a large exit angle, and then travels in a straight line .
  • Route P1 indicates that it reaches the side wall of the color filter layer and cannot exit.
  • Route P2 indicates that although it reaches the top surface of the color filter layer (ie, its light-emitting surface), it cannot be emitted due to total reflection.
  • Route P3 means that even if it is emitted, the emission angle is very large, which will not affect the front view. Furthermore, even if there are scattering particles in the color filter layer, their overall impact on the light path is relatively limited, and most of the incident light will not be emitted from the light exit surface at a small exit angle.
  • FIG. 1( b ) shows the situation of the wavelength conversion layer 11 with the same size. Because there are a large number of wavelength conversion particles (such as quantum dot particles) in the wavelength conversion layer. The same incident light P1 , P2 and P3 as in FIG. 1( a ) will inevitably encounter wavelength conversion particles during the travel of the wavelength conversion unit.
  • wavelength conversion particles such as quantum dot particles
  • the wavelength of the incident light is converted into new light, and its light direction will no longer be limited by the incident angle, and can be emitted from the front of the wavelength conversion unit, causing cross-color problems. Due to at least part of the above reasons, the design of the color filter OLED display panel cannot avoid the cross-color problem of the wavelength conversion display panel.
  • the present disclosure provides:
  • the light-emitting layer on the substrate substrate is the light-emitting layer on the substrate substrate.
  • the display panel includes sub-pixels arranged in an array, and the sub-pixels arranged in the array include adjacent first sub-pixels and second sub-pixels, and each of the first sub-pixels and second sub-pixels One comprising a light-emitting unit in the light-emitting layer and a wavelength conversion unit in the wavelength conversion layer, the light-emitting unit and the wavelength conversion unit are stacked and separated by the transparent spacer layer ,
  • the light-emitting units of the first sub-pixel and the second sub-pixel are separated by the first pixel-defining layer in the light-emitting layer, and the distance between the top surfaces is d2,
  • the wavelength conversion unit of the first sub-pixel is a first wavelength conversion unit and the brightness change rate of the light emitted by the light-emitting unit is ra
  • the wavelength conversion unit of the second sub-pixel is a second wavelength conversion unit and The luminance change rate of the light emitted by the light-emitting unit is rb
  • the wavelength conversion units of the first sub-pixel and the second sub-pixel are separated by a second pixel-defining layer in the wavelength conversion layer
  • the projection length of the light path passing through the transparent spacer layer on the base substrate is less than or equal to d2+d4 2 .
  • the display panel of the present disclosure includes at least a three-layer structure on the base substrate in the thickness direction of the panel, that is, a light emitting layer, a transparent spacer layer and a wavelength conversion layer.
  • the luminescent layer is responsible for emitting light.
  • the transparent spacer layer is used to separate the light-emitting layer and the wavelength conversion layer, and can encapsulate or carry the two layers.
  • a transparent spacer layer is a layer of material that is transparent at least in the visible range. In this way, the light emitted from the light emitting unit can reach the wavelength conversion unit after passing through the transparent spacer layer.
  • the wavelength conversion layer is used to convert the wavelength of the light emitted by the light-emitting layer and passed through the transparent spacer layer into a desired wavelength, so as to realize color display.
  • the base substrate is used to carry the above-mentioned three-layer structure.
  • the display panel of the present disclosure also includes sub-pixels arranged in an array.
  • FIG. 2 shows a partial schematic diagram of relevant film layers of the display panel.
  • the display panel extends in the XY plane, and takes the Z direction as the thickness direction.
  • the Z direction is the direction from the back to the front of the display panel.
  • the light-emitting side of the display panel is referred to as the "top side” or “front side”
  • the opposite side is referred to as the "bottom side” or “back side”
  • the direction perpendicular to the direction from the bottom side to the top side is "transverse". It should be understood that these directions are relative and not absolute.
  • FIG. 2 shows sub-pixels arranged in 6 ⁇ 3 rectangular arrays. If the X direction is the row direction and the Y direction is the column direction, the sub-pixels in the figure are arranged in an array of 3 rows and 6 columns. They form 6 pixels arranged in 3 rows and 2 columns, and each pixel includes 3 sub-pixels arranged in the row direction.
  • the present disclosure does not require the arrangement form of sub-pixels of different colors.
  • the arrangement form may be that three sub-pixels in the same pixel have different colors, but the sub-pixels in the same column have the same color, and of course other forms may also be used.
  • the sub-pixels are rectangular, with the long side in the Y direction and the short side in the X direction.
  • the subpixels in the figure are all drawn to be of the same size. It should be understood that the color distribution, shape and size of the sub-pixels can be properly selected as long as they do not conflict with the principles of the present disclosure.
  • the dotted box in Figure 2 marks the approximate range of one of the sub-pixels.
  • the sub-pixels arranged in an array include adjacent first sub-pixels and second sub-pixels.
  • a light-emitting unit in the light-emitting layer and a wavelength conversion unit in the wavelength conversion layer are included, the light-emitting unit and the wavelength
  • the conversion units are stacked and separated by the transparent spacer layer. Laminated means that they overlap in the thickness direction of the display panel, that is, the Z direction.
  • each of the first sub-pixel and the second sub-pixel includes a light-emitting unit in the light-emitting layer and a wavelength conversion unit in the wavelength conversion layer, and the wavelength conversion unit receives the underlying light with its bottom surface. The light is emitted upwards from the top surface of the light-emitting unit, and the wavelength of the light is converted and emitted from the top of the wavelength conversion unit to complete the display.
  • Fig. 3 shows a schematic cross-sectional view of the sub-pixel in the dotted box in Fig. 2 at the position A-A' in the X-Z plane.
  • the sub-pixel includes a stacked light emitting unit 31 in the light emitting layer 3 and a wavelength converting unit 11 in the wavelength converting layer 1 , which are separated by a transparent spacer layer 2 .
  • the interface between the light emitting unit 31 and the transparent spacer layer 2 that is, its top surface, emits light toward the transparent spacer layer.
  • the interface between the wavelength conversion unit 11 and the transparent spacer layer 2 that is, its bottom surface, receives light from the transparent spacer layer, and the light is emitted from its top surface after wavelength conversion.
  • the wavelength conversion unit 11 and the light emitting unit 31 face each other in the vertical direction, or the orthographic projections of the bottom surface of the wavelength conversion unit and the top surface of the light emitting unit on the base substrate overlap, so that most of the The light emitted from the top surface reaches the lower surface of the wavelength conversion unit 11 after passing through the transparent spacer layer and enters the wavelength conversion unit 11 .
  • the wavelength conversion particles in the wavelength conversion unit convert the wavelength of incident light and emit from the top surface thereof.
  • the light-emitting layer is a layer that emits light, and the emitted light can be converted into other colors through the wavelength conversion layer above it, and can also optionally not convert colors, so as to realize color display.
  • the light emission of the display panel of the present disclosure is realized by the light emitting unit in the light emitting layer.
  • the light emitting units are arranged in an array.
  • the light emitting unit can typically use OLED to emit light, but it can also be in other light emitting modes, such as QLED or Mini-LED or Micro-LED using inorganic quantum dot light-emitting materials.
  • a plurality of such light-emitting units are arranged in an array parallel to the display surface of the display panel, thereby forming a light-emitting dot matrix.
  • Each sub-pixel of the display panel of the present disclosure has an independent light-emitting unit, which can cooperate with, for example, an array substrate to realize the individual lighting and extinguishing of the backlight of each sub-pixel.
  • the light emitting units of different color sub-pixels are the same.
  • a first pixel defining layer defining the light emitting cell array is included in the light emitting layer. It should be understood that the "first pixel definition layer" referred to in this disclosure actually defines the range of each sub-pixel, such as the range of red, green and blue sub-pixels, rather than the total range of a color RGB pixel.
  • the patterned first pixel-defining layer is arranged in the light-emitting layer and encloses a plurality of spaces arranged in an array for setting the light-emitting units.
  • both sides of the light emitting unit 31 are defined by the first pixel defining layer 32 .
  • first pixel defining layer and the light emitting unit illustrated in FIG. 3 are both rectangular and have vertical sidewalls, they may also have inclined sidewalls.
  • the first pixel-defining layer may be in a forward trapezoidal shape, correspondingly forming an inverted trapezoidal light emitting unit.
  • the trapezoidal first pixel defining layer can provide a larger light emitting surface, and a reflective layer can also be arranged on the side wall of the first pixel defining layer, thereby increasing the light output of the light emitting unit.
  • the present disclosure focuses on the geometric features at the top of the first pixel defining layer and the top surface of the light emitting unit, therefore, no special limitation is imposed on the shapes of the first pixel defining layer and the light emitting unit.
  • the display panel of the present disclosure is a display panel including a wavelength conversion element.
  • the wavelength conversion element is used to convert the wavelength of the light emitted by the light emitting unit into light of other colors. It should be noted that in this disclosure, wavelength conversion is not the same as wavelength selective transmission. Wavelength conversion refers to converting the wavelength of incident light to another wavelength without additional energy, while wavelength selective transmission refers to allowing only a part of the wavelengths of the incident light to pass through and blocking other wavelengths of light from passing through. Pass. Wavelength conversion can be down-conversion or up-conversion. Down-conversion is the opposite of up-conversion and refers to the conversion of light with a shorter wavelength to light with a longer wavelength. By changing the color of light using different wavelength conversion units, it is possible to realize color display using only one color light emitting unit.
  • wavelength conversion unit in the wavelength conversion layer, which is used to convert the wavelength emitted by the light emitting unit in the sub-pixel into a desired color.
  • a red wavelength conversion unit can convert a blue backlight into red light
  • a green wavelength conversion unit can convert a blue backlight into green light.
  • the example of wavelength conversion unit can be a quantum dot (quantum dot, QD) material part, inorganic phosphor material part or organic fluorescent material part, and it comprises transparent host material and the quantum dot dispersed in host material, inorganic phosphor powder or organic fluorescent material.
  • the wavelength conversion unit can also be made of other wavelength conversion materials.
  • the matrix material may be a transparent organic material such as a resin, eg cured photoresist resin, or cured ink.
  • a resin eg cured photoresist resin
  • cured ink Any suitable down conversion material may be used as the down conversion material, which is not specifically limited in the present disclosure. Among them, the QD down-conversion material is particularly preferable since the down-conversion performance can be controlled by the particle size.
  • the wavelength conversion unit may include a base resin and quantum dots mixed with (or dispersed in) the base resin.
  • the base resin may be a medium in which quantum dots are dispersed.
  • the base resin may be formed of at least one of various resin composite materials commonly referred to as adhesives.
  • the inventive concept is not limited thereto.
  • a medium capable of dispersing quantum dots can be used as a base resin regardless of its name, additional functions, and/or constituent materials.
  • the base resin may be a polymer resin.
  • the base resin may be an acrylic-based resin, a urethane-based resin, a silicon-based resin, or an epoxy-based resin.
  • the base resin may be a transparent resin.
  • Quantum dots may be particles configured to convert the wavelength of incident light.
  • Each of the quantum dots may be a material with a crystal structure having a size of a few nanometers, and may be composed of hundreds to thousands of atoms.
  • Quantum dots can exhibit quantum confinement effects, where the energy bandgap is increased due to the small size.
  • the quantum dot When light of a wavelength corresponding to energy greater than the energy bandgap is incident to the quantum dot, the quantum dot may be excited by absorbing the light, and then may transition to a ground state while emitting light of a specific wavelength. The energy of emitted light may correspond to an energy band gap.
  • the luminescent properties of quantum dots caused by the quantum confinement effect can be adjusted by adjusting the size and/or composition of the quantum dots.
  • Quantum dots can be formed from Group II-VI compounds, Group III-V compounds, Group IV-VI compounds, Group IV elements, Group IV compounds, or any combination thereof.
  • Group II-VI compounds may be selected from the group consisting of: binary compounds selected from the group consisting of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS and any mixture thereof; AgInS, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS and any mixture thereof and quaternary compounds selected from the group consisting of HgZnTeS, CdZnSeS, CdZnSeTe, CdZ
  • the group III-V compound may be selected from the group consisting of: binary compounds selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and any mixture thereof; A ternary compound selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, and any mixture thereof; and a ternary compound selected from the group consisting of GaAlNP, GaAlNAs, Quaternary compounds of the group consisting of GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb and any
  • Group IV-VI compounds may be selected from the group consisting of: binary compounds selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe and any mixture thereof; selected from SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, a ternary compound selected from the group consisting of PbSTe, SnPbS, SnPbSe, SnPbTe, and any mixture thereof; and a quaternary compound selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and any mixture thereof.
  • Group IV elements may be selected from the group consisting of Si, Ge and mixtures thereof.
  • the Group IV compound may be a binary compound selected from the group consisting of SiC, SiGe, and mixtures thereof.
  • the binary, ternary, or quaternary compounds may be present in the quantum dots in a substantially uniform concentration.
  • the concentration of binary, ternary or quaternary compounds in one portion of the quantum dots may be different than the concentration of binary, ternary or quaternary compounds in another portion of the quantum dots.
  • Each of the quantum dots may have a core-shell structure including a core and a shell surrounding the core.
  • the quantum dots may have a core/shell structure in which one quantum dot surrounds another quantum dot.
  • the interface of the core and the shell may have a concentration gradient in which the concentration of elements present in the shell becomes gradually smaller towards the center.
  • Quantum dots can be nano-sized particles.
  • Each of the quantum dots may have a full width at half maximum (FWHM) of an emission wavelength spectrum of about 45 nm or less, specifically about 40 nm or less, and more specifically about 30 nm or less, and color purity may be improved within this range and/or color reproducibility.
  • FWHM full width at half maximum
  • light emitted through the quantum dots may be emitted in all directions, and thus, a wide viewing angle may be improved or realized.
  • each of the quantum dots may be a general shape known in the art, but the shape of each of the quantum dots is not limited to a specific shape.
  • each of the quantum dots can have a spherical shape, a pyramidal shape, a multi-armed shape, a cubic nanoparticle shape, a nanotube shape, a nanowire shape, a nanofiber shape, or a nanoplate particle shape.
  • the color of light emitted from the quantum dots can be controlled according to the particle size of the quantum dots, and thus, the quantum dots can emit one of various emission colors of light, such as red, green or blue, especially red or green.
  • QD is used as an example of the wavelength conversion material for description.
  • the wavelength conversion unit in the wavelength conversion layer includes a first wavelength conversion unit that can convert incident light into first color light.
  • the first color may be red, that is, there is a red wavelength conversion unit in the wavelength conversion unit.
  • the wavelength conversion unit in the wavelength conversion layer may also include a second wavelength conversion unit, or more other wavelength conversion units.
  • red may be selected as the first color and green as the second color.
  • red may be the first color
  • green may be the second color
  • blue may be the third color.
  • the wavelength conversion layer may further include a transparent color-resist unit.
  • Transparent color-resist units are transparent to incident light and do not undergo wavelength conversion.
  • the blue OLED emission in the blue sub-pixel can pass through the wavelength conversion layer without undergoing wavelength conversion, and can be directly used for blue display.
  • the transparent color-resist unit may be a light-diffusing unit, for example, containing scattering particles, so that the incident light is scattered without substantially changing the wavelength, which is beneficial to uniform display.
  • the light-diffusing unit can be made of light-diffusing resin with light-diffusing ability, so as to make the blue light more uniform after passing through it.
  • the display panel of the present disclosure may be a down conversion type OLED display panel.
  • a down-conversion OLED display panel uses a short-wavelength OLED of one color as a light emitting unit, typically a blue OLED.
  • different down-converting materials such as QD
  • QD different down-converting materials
  • a down-conversion material converts the blue light emitted by the blue OLED to green light.
  • blue itself is one of the sub-pixel colors displayed by RGB
  • the blue sub-pixel the blue light may not be down-converted and directly used for blue sub-pixel display.
  • red-green-blue (RGB) color display is realized.
  • RGB red-green-blue
  • the patterned second pixel defining layer is disposed in the wavelength conversion layer, enclosing a plurality of spaces arranged in an array for arranging wavelength conversion units.
  • both sides of the bottom surface of the wavelength converting unit 11 are defined by the bottom of the second pixel defining layer 12 .
  • Both the second pixel defining layer and the wavelength converting unit illustrated in FIG. 3 are rectangular and have vertical sidewalls. However, they can also have inclined side walls.
  • the second pixel defining layer is also used to enclose the space for setting the transparent color resist unit. The specific shape of the second pixel defining layer will be further elaborated below.
  • Fig. 4 shows a cross-sectional view at position A-A' in the X-Z plane of a pixel including three sub-pixels arranged side by side in Fig. 2 .
  • the first pixel defining layer 32 defines three light emitting units 31a, 31b and 31c
  • the second pixel defining layer 12 defines three units 11a, 11b and 11c.
  • 11a and 11b are wavelength conversion units
  • 11c is a transparent color-resist unit.
  • Adjacent sub-pixels are shown in the figure.
  • the sub-pixels in the present disclosure may be sub-pixels including wavelength conversion units, or sub-pixels including transparent color-resist units.
  • the display of at least three colors can only be realized if at least two adjacent sub-pixels in the disclosed sub-pixels contain wavelength conversion units and have different colors.
  • the third color can be obtained by converting the light emitted by the light-emitting unit through another color wavelength, or by passing the light emitted by the light-emitting unit through the transparent color-resist unit. Therefore, in the present disclosure, two adjacent sub-pixels each having a wavelength conversion unit are optionally used as the first and second sub-pixels, and their order can also be reversed.
  • the light emitting layer includes a first pixel defining layer and a light emitting unit
  • the wavelength conversion layer includes a second pixel defining layer and a wavelength converting unit
  • the transparent spacer layer is between the light emitting layer and the wavelength converting layer.
  • the bottom surface of the transparent spacer layer is the top surface of the light-emitting unit in the light-emitting layer
  • the top surface of the transparent spacer layer is the bottom surface of the wavelength conversion unit (or transparent color-resist unit) in the wavelength conversion unit. As shown in FIG.
  • the top surface of the first pixel defining layer 32 in the light emitting layer 3 and the top surface of the light emitting unit 31 are in the same plane, and this plane is the bottom surface of the transparent spacer layer 2 .
  • the bottom surface of the second pixel defining layer 12 in the wavelength conversion layer 1 and the bottom surface of the wavelength conversion unit/transparent color resist unit 11 are in the same plane, and this plane is the top surface of the transparent spacer layer 2 .
  • the top surface and the bottom surface of the transparent spacer layer are not necessarily actual layered interfaces of different materials, but may also be partition surfaces set in the same material.
  • a part of the top of the first pixel defining layer may actually be within the geometric range of the transparent spacer layer.
  • the bottom surface of the transparent spacer layer that is, the benchmark of the top surface of the light-emitting layer is determined according to the shape of the top surface of the first pixel defining layer
  • the transparent spacer layer is determined according to the shape of the bottom surface of the second pixel defining layer.
  • the top surface of the spacer layer is the reference of the bottom surface of the wavelength conversion layer.
  • the top surface of the first pixel defining layer is a plane.
  • the top surface can be used as a reference plane for the top surface of the light-emitting layer.
  • a transparent spacer layer is used on both sides thereof.
  • the part lower than the reference plane is divided into the light-emitting unit, and the part higher than the reference plane is divided into the transparent spacer layer.
  • the top of the first pixel defining layer may be non-planar and slightly raised in the center. At this time, the first pixel defining layer does not have a flat top surface. However, the planar interface between the first pixel defining layer and the transparent spacer layer still needs to be demarcated.
  • the pixel-defining layer plays a blocking role for the light leakage between adjacent sub-pixels, when considering the cross-color related to the light leakage, consider such a point on the boundary of the first pixel-defining layer: it can be seen from the light-emitting unit
  • the light-emitting material layer of the light-emitting material layer receives enough light, and can provide corresponding light to the adjacent wavelength conversion unit.
  • the inflection point at the maximum slope change rate on the first pixel-defined layer profile is selected as the above-mentioned point. After such points are selected on both sides of the first pixel defining layer, their average height is used as a benchmark for dividing the transparent spacer layer and the light emitting layer.
  • this reference depends on the profile of the first pixel-defining layer, it is independent of the actual boundaries of the material. In the space above this reference, there may actually be some material of the first pixel defining layer (eg the slightly raised portion mentioned above). In the space below the reference below the two sides of the first pixel defining layer, some materials that are the same as those of the transparent spacer layer may actually exist.
  • the actual film layer structure is fitted to a film layer with a standard flat interface, and further calculation and design are carried out. Specifically, the width occupied by the first pixel defining layer on the reference line is taken as the width d2 between the top surfaces of adjacent light emitting units.
  • the light emitting unit typically has an anode, a layer of light emitting material and a cathode therein, and usually the cathode is a common cathode covering the top of the layer of light emitting material and the first pixel defining layer.
  • Figure 5(a) shows a typical structure. Wherein, 311 is an anode, 313 is a luminescent material layer, and 315 is a common cathode.
  • the top surface of the first pixel defining layer is used as a reference for dividing the light emitting layer and the transparent spacer layer. Because the light conditions at the endpoints of the top surface most represent the principles of the present disclosure.
  • the luminescent layer 3 and the transparent spacer layer 2 are divided based on the line connecting the upper left corner A1 and the upper right corner A2 of the trapezoid and its extension.
  • the common cathode above the first pixel defining layer also belongs to the range of the transparent spacer layer.
  • FIG. 5( b ) shows another typical situation, in which the common electrode 315 and the surface below it are profiled and the upper surface is concave-convex. However, this does not affect the division of the transparent spacer layer and the light emitting layer. The two end points of the top surface of the first pixel definition layer are still used as the division basis.
  • the first pixel defining layer and the light-emitting unit have a common plane top surface, and this common plane top surface is used as the light-emitting layer interface with the transparent spacer layer.
  • this common plane top surface is used as the light-emitting layer interface with the transparent spacer layer.
  • Figure 5(c) shows a more complex structure of pixels defining the perimeter of the layer than Figure 5(a).
  • the top surface of the first pixel defining layer 32 is slightly raised, and is no longer an ideal plane.
  • the position on the first pixel electrode layer with the largest change rate of the tangent slope is selected as the position of the top surface of the light emitting unit and the position of the bottom surface of the transparent spacer layer.
  • the position where the rate of change of the tangent slope is the largest is the inflection point where the substantially vertical sidewall of the first pixel electrode layer transitions to the substantially horizontal top surface.
  • the light from the luminescent material layer 313 can be fully obtained, and there is enough light emitted to the side without being blocked by the first pixel defining layer 32 .
  • the endpoint of the top surface is where the rate of change of the tangent slope is the largest.
  • Figure 5(d) shows an even more complex structure.
  • the first pixel defining layer 32 itself forms a "mushroom shape" with a large top and a small bottom.
  • the position of the inflection point with the largest tangent slope change rate above the widest point (dashed line position) of the first pixel defining layer is selected as the position of the top surface of the light emitting unit and the position of the bottom surface of the transparent spacer layer. This is because, in the part below the widest point, the light emission from the points on the sidewall of the first pixel defining layer cannot reach the adjacent sub-pixels, so they need not be taken into consideration.
  • the present disclosure considers the light emission near the top surface of the first pixel defining layer and the light incident near the bottom surface of the second pixel defining layer, therefore, the first pixel defining layer or other parts of the second pixel defining layer
  • the geometry of is not the focus of this disclosure.
  • the cross section of the first pixel defining layer may be a regular trapezoid with a narrow top and a wide bottom, a rectangle with almost the same width at the top and bottom, or an inverted trapezoid with a wide top and a narrow bottom. This has no great influence on determining the distance d2 between the light emitting units.
  • the delamination interface between the light emitting layer 3 and the transparent spacer layer 2 is determined according to the position of the inflection point.
  • the part higher than the top of the first pixel defining layer can be regarded as a part of the transparent spacer layer, while it can be placed at the top of the first pixel defining layer.
  • the portion between the first pixel defining layers that is lower than the top surface of the first pixel defining layers is used as a part of the light emitting unit.
  • Figure 5(e) shows the division of the layer structure when the lower surface of the common cathode is non-planar in one embodiment.
  • the first pixel defining layer 32 defines the height of the light emitting layer 3 , and a part of the common cathode 315 covered thereon is below the top surface of the first pixel defining layer 32 .
  • the part of the common cathode 315 above the first pixel defining layer can be regarded as a part of the transparent spacer layer 2
  • the part between the first pixel defining layer 32 can be regarded as a part of the light emitting unit 31 .
  • the boundary between the transparent spacer layer 2 and the light-emitting layer 3 is indicated by the lower dotted line.
  • the boundary between the first pixel defining layer and the light emitting unit may not be a straight line. In this case, its boundaries are represented by straight mean lines.
  • the position of the plane top surface of the first pixel defining layer is used as a benchmark for determining the light emitting layer and the transparent spacer layer.
  • the height of the standard plane top surface can be obtained by using the average height of these boundary points.
  • the inflection point of the tangent slope at the top of the pixel defining layer can be used as the boundary point of the top surface of the light emitting unit.
  • the wavelength conversion layer 1 there may be a covering layer or an encapsulation layer covering the wavelength conversion material 111 in the wavelength conversion layer 1 113.
  • a transparent encapsulation layer 21 there may be a transparent encapsulation layer 21 .
  • the interface between the wavelength conversion layer and the transparent spacer layer is divided based on the bottom surface of the second pixel defining layer. , a part of the cover layer 113 is included in the wavelength conversion unit 11, and another part is included in the transparent spacer layer 2.
  • the boundary between the transparent spacer layer 2 and the wavelength converting layer 1 is indicated by the upper dotted line.
  • FIG. 5(f) shows that when the bottom surface of the second pixel defining layer is not flat, the inflection point is similarly determined, thereby dividing the interface between the wavelength conversion layer and the transparent spacer layer.
  • 12 is the second pixel definition layer.
  • the inflection points B1 and B2 are determined according to the contour shape of the bottom surface of the second pixel defining layer 12, and the boundaries between the wavelength conversion layer 1 and the transparent spacer layer 2 are divided based on their average height.
  • Part of the encapsulation layer 113 belongs to the transparent spacer layer.
  • the present disclosure provides special dimensioning of the regions between sub-pixels to at least partially solve the cross-color problem.
  • FIG. 6( a ) is a schematic diagram showing a part of sub-pixel a on the left and sub-pixel b on the right by the first pixel defining layer 32 and the second pixel defining layer 12 .
  • the left sub-pixel a includes a stacked light emitting unit 31a and a wavelength conversion unit 11a
  • the right sub-pixel b includes a stacked light emitting unit 31b and a wavelength conversion unit 11b.
  • the top surface of the first pixel defining layer 32 is in the same plane as the top surfaces of the light emitting units 31a, 31b, and the bottom surface of the second pixel defining layer 12 is also in the same plane as the bottom surfaces 11a, 11b of the wavelength conversion units.
  • the top surface of the light-emitting unit is, for example, the top surface of a transparent pixel electrode of its OLED, such as a transparent cathode.
  • the spacer layer is a single material.
  • the light emitted to the area I (the area on the right side of the line segment A1 to B2) can reach the adjacent sub-pixel 11b, and the light emitted to the area II (the left side of the line segment A1 to B1
  • the light emitted from area ) can reach 11 a of the sub-pixel, while the light emitted to area III (the area on the left side of the line segment A1 to B2 and the right area of the line segment A1 to B1 ) will be blocked by 12 .
  • the light reaching 11b will cause 11b to emit light, which may cause cross-color.
  • the concept of the present disclosure is that, although there is inevitably light directed toward area I and reaching 11b, as long as the luminous brightness of sub-pixel b caused by this is sufficiently small compared with the luminance of sub-pixel a that emits light, the viewer will not be able to It is found that the light emission of the sub-pixel b does not cause substantial cross-color.
  • the purpose of the present disclosure is to control the relative luminance of the sub-pixel b rather than simply blocking light leakage between adjacent sub-pixels.
  • Luminance is defined as the luminous intensity per unit projected area, and the unit is nit, that is, candela/square meter (cd/m 2 ).
  • Luminous intensity is the luminous flux per unit solid angle. Luminous flux refers to the radiant power that the human eye can perceive, and the unit is lumen (lm).
  • the luminous flux at a particular wavelength is proportional to the product of the radiant power and the relative vision rate for that wavelength.
  • the relative viewing rate is also called the spectral luminous efficiency function or the human eye viewing function. Standard spectral luminous efficiency functions are available, for example, from the International Commission on Illumination (CIE).
  • the luminous brightness observed from the front of the wavelength conversion unit is related to the initial power of the light source that provides the backlight for the wavelength conversion unit, the wavelength change caused by wavelength conversion, and the conversion ability of the wavelength conversion unit itself to incident light.
  • the ability of the wavelength conversion unit (or transparent color-resist unit) to change brightness is summarized as a parameter of “brightness change rate”.
  • the luminance change rate is used to represent the luminance change generated during the process of the incident light being subjected to the action of the wavelength conversion unit to obtain the wavelength-converted outgoing light.
  • the luminance change rate is a ratio of the luminance of the wavelength-converted light emitted from the wavelength conversion unit to the luminance of light incident on the wavelength conversion unit.
  • the wavelength conversion unit there may be a part of incident light that does not undergo wavelength conversion due to not encountering wavelength conversion particles and is directly emitted through the wavelength conversion unit.
  • the remaining incident light luminance after converting the unit will basically not affect the final display luminance, nor will it affect cross-color. Therefore, when considering the luminance change rate in the present disclosure, only the luminance of the wavelength-converted light is calculated.
  • the brightness change rate is affected by the combination of light wavelength change and wavelength conversion ability. Changes in the wavelength of light can affect the relative visibility of its brightness, and wavelength conversion capabilities can affect changes in its photon count. In the quantum dot wavelength conversion unit, the wavelength conversion capability is affected by its quantum efficiency.
  • the luminance change rate represents the ratio of the luminance of light emitted from the transparent color-resist unit to the luminance of light incident on the transparent color-resist unit. Because there is no change in the wavelength, the change in its brightness is basically only affected by the change in the number of photons.
  • the luminance change rate of a specific wavelength conversion unit or transparent color resist unit for a specific incident light wavelength can be measured through experiments, or can be calculated according to material properties.
  • a collimated backlight of known brightness can be used to illuminate the bottom surface of the wavelength conversion unit structure, and the brightness of the wavelength converted light can be measured on the top surface of the wavelength conversion unit to obtain the brightness change rate.
  • the tested wavelength conversion unit can be a prefabricated analog sample, so that dimension design can be carried out according to the test results.
  • the ratio of the emission luminance of the wavelength conversion unit of an adjacent sub-pixel (such as pixel b) to the emission luminance of the wavelength conversion unit of a sub-pixel (such as pixel a) that provides light is represented by a parameter p.
  • the critical p-value is specified to be less than 5%. More preferably, the critical p-value is specified to be less than 3.1%. Most preferably, the critical p-value is less than 2%. At less than 2%, it is ensured that no crossover is observed for any color combination.
  • the present disclosure ensures that the above-mentioned p-value is below the required critical value by designing the geometry between the sub-pixels.
  • luminescence of 11b (wavelength converted luminescence) caused by luminescence of A1 is caused by light emitted into region I
  • luminescence of 11a caused by light emitted into region II.
  • wavelength-converted luminescence has an effect on the brightness of the light due to changing the wavelength.
  • the wavelengths converted in 11a and 11b are different, even if they are irradiated with light of the same intensity, the brightness of display is also different.
  • the parameter r is used to characterize the change ratio of the wavelength conversion material to the brightness of incident light. That is, when the brightness of incident light is B, the brightness of outgoing light is B ⁇ r. It is said that the luminance change rate of the first sub-pixel a is ra, and the luminance change rate of the second sub-pixel is rb. ra and rb are parameters related to material properties. It should be noted that the luminance change rate may be a value greater than 100% due to a change in wavelength.
  • the resulting total brightness of the outgoing light is B I
  • the resulting total brightness of the outgoing light is BI ⁇ rb
  • the total brightness of the light entering 11a is D II
  • ra and rb are material-dependent parameters, while the total intensity of light incident on 11b and the total intensity of light incident on 11a are geometry-dependent parameters.
  • the total intensity of the light incident from point A1 to 11 b is approximately the total intensity of the light rays with an exit angle of ⁇ .
  • the intensity will be attenuated to a certain extent.
  • the transparent spacer layer has good transmittance to the light emission of the light-emitting unit, and the overall attenuation degree is not large; on the other hand, the attenuation occurs at various angles, and has little effect on the relative brightness change of adjacent pixels. Therefore, the attenuation due to the transmittance of the material in the transparent spacer layer is ignored.
  • the outgoing light at the left boundary of the angle ⁇ will reach the left boundary point B2 of 11b, and the outgoing light at the right boundary will reach the right boundary point C2 of 11b.
  • the angle ⁇ in FIG. 6( a ) looks small, the width of 11b is actually much wider than shown in the figure. Therefore, the angular proportion of the angle ⁇ in the region I is not small.
  • the intensity of the light emitted by A1 is unevenly distributed throughout the range of the output angle, and when the output angle is large, its intensity is relatively much smaller (will be described in detail below). Therefore, the intensity of light beyond the ⁇ angle is negligible here.
  • the light within the range of ⁇ can reach 11a.
  • the light beyond the left side of C1 does not contribute to the luminescence of 11a, but the angle is very large and the total intensity is small, which is also negligible.
  • the luminescence corresponding to the small angle on the right side of B1 does not contribute to the luminescence of 11a, a large amount of luminescence on the left side of A1 can reach 11a and form a certain compensation for the luminescence.
  • the total intensity to 11a is roughly the total intensity of the light emitted from A1 to the ⁇ range and all the light on its left side, and the total intensity of the light incident to 11b is the light with an exit angle greater than ⁇ in the range of 0-90° on the right side , and the total intensity of light incident on 11a is the total intensity of light at all exit angles in the range of -90-0° on the left.
  • the relative brightness of the light incident on 11b and 11a from A1 is (total intensity of light rays whose exit angle is greater than ⁇ /total intensity of all light rays) ⁇ (rb/ra).
  • the relative brightness should not be higher than the critical value of p1, such as 5%, preferably 3.1%, more preferably 2%, so as to minimize cross-color phenomenon.
  • p1 is less than 2%, cross-color phenomenon can basically be completely avoided.
  • (total intensity of light rays whose exit angle is greater than ⁇ /total intensity of all light rays) ⁇ (rb/ra) p1.
  • the total intensity of light within a certain angle range can be calculated according to the relationship curve between the luminous intensity and angle at point A1.
  • the total intensity can be obtained by integrating by angle in the luminous intensity-angle curve.
  • the critical value of ⁇ is calculated from the above equation. Further, according to the critical value, the geometric structure between 12, 32 and the transparent spacer layer can be designed. When B2 is far enough to the right (beyond the critical position), all the rays with the exit angle of ⁇ in the A1 luminescence cannot reach 11b, and therefore, the total intensity of the rays reaching 11b after being converted into wavelength by 11b has the same brightness as reaching 11a
  • the ratio of the luminance (that is, the relative luminance) generated after the wavelength conversion of the ray of light must be smaller than the critical value p1, thereby solving the cross-color problem.
  • the transparent spacer layer is a single-layer material with uniform refractive index
  • the intensity of light with an exit angle greater than ⁇ accounts for 2.5%.
  • the corresponding angle ⁇ is, for example, 80°.
  • the above-mentioned transverse distance is the sum of the width d2 of the top surface of 32 and the portion d42 of the bottom surface of 12 beyond the boundary of 32 .
  • d2+d4 2 is designed to be greater than this critical value, the cross-color problem can be solved.
  • the width d2 of 32 is 10 microns
  • the part d4 2 where B2 exceeds A2 is greater than 1.34 microns.
  • FIG. 6( a ) only shows the analysis of color crossover from the left sub-pixel a to the right sub-pixel b.
  • the color crossover from the right sub-pixel to the left sub-pixel can also be analyzed symmetrically.
  • the critical value p2 can be set according to its color selection. p2 ⁇ 5%, more preferably ⁇ 2%. It is possible to make p2 equal to p1, as long as there is no obvious cross-color. It should be noted that the relationship of various parameters in the present disclosure can be appropriately extended to other sub-pixels, as long as the principle of the present disclosure is complied with.
  • the first pixel between defines the orthographic projection of the boundary of the layer on the base substrate, the bottom surface of the first wavelength conversion unit and the second wavelength conversion unit between the first sub-pixel and the second sub-pixel
  • the displacement of the orthographic projection of the boundary of the pixel-defining layer on the substrate is d4 1 ,
  • the projection length of the light path passing through the transparent spacer layer on the base substrate is less than or equal to d2+d4 1 .
  • the lateral distance between A1 and B2 or A2 and B1 satisfies the above relationship, cross-color can be effectively avoided.
  • the lateral distance d2+d4 1 or d2+d4 2 satisfies a critical value greater than the projection length of the optical path corresponding to the corresponding critical angle ⁇
  • cross-color can be avoided.
  • it is not necessary to set the above-mentioned lateral distance too large it only needs to be slightly larger than the critical value.
  • the difference between the lateral distance and the critical value can be as small as possible.
  • the difference between the lateral distance and the critical value may be less than or equal to 10 ⁇ m.
  • the difference between the length of the projection of the light path passing through the transparent spacer layer on the base substrate and d2+d4 2 Less than or equal to 5 ⁇ m, less than or equal to 4 ⁇ m, less than or equal to 3 ⁇ m, less than or equal to 2 ⁇ m, less than or equal to 1 ⁇ m, less than or equal to 0.5 ⁇ m, or d2+d4 2 is designed to just correspond to the case of the critical exit angle ⁇ 1 .
  • the difference between the length of the projection of the optical path passing through the transparent spacer on the substrate and d2+d4+ 1 is less than or equal to 5 ⁇ m, less than or equal to 4 ⁇ m, and less than or equal to 3 ⁇ m , less than or equal to 2 ⁇ m, less than or equal to 1 ⁇ m, less than or equal to 0.5 ⁇ m, or d2+d4 1 is designed to just correspond to the case of the critical exit angle ⁇ 2 .
  • the geometric design of the present disclosure does not add a light-shielding component between adjacent sub-pixels, and provides a lower limit for the distance between adjacent sub-pixels, so that the resolution can be improved as much as possible without cross-color occurrence.
  • Fig. 6(b) schematically shows the structure between two adjacent sub-pixels a and b in an embodiment finer than the schematic structure of Fig. 6(a), where the transparent spacer layer has multiple stacked sublayer.
  • the first sub-pixel a includes a light emitting unit 31a and a wavelength conversion unit 11a
  • the second sub-pixel b includes a light emitting unit 31b and a wavelength conversion unit 11b.
  • the boundary between the top surface of the light emitting unit of the first sub-pixel and the first pixel defining layer is A1
  • the boundary between the bottom surface of the wavelength conversion unit and the second pixel defining layer is B1.
  • the boundary between the top surface of the light-emitting unit of the second sub-pixel and the first pixel definition layer is A2, and the boundary between the bottom surface of the wavelength conversion unit and the second pixel definition layer is B2.
  • the light emitting units 31 a and 31 b each include an anode 311 and a light emitting material layer 313 . The two are separated by the first pixel defining layer 32, and the distance between the top surfaces of the light emitting units 31a and 31b is the width d2 at the top surface of the first pixel defining layer between them, that is, the distance between point A1 and Width between A2 points.
  • the light emitting unit includes an anode and a light emitting material layer.
  • the schematic transparent spacer layer shown in FIG. 6( b ) has four film layers, including a common cathode 315 , a first inorganic layer 211 , an organic layer 212 and a second inorganic layer 213 .
  • a second pixel defining layer Between the wavelength converting units 11a and 11b is a second pixel defining layer.
  • the distance between the bottom surfaces of the wavelength conversion units 11a and 11b is the width d3 at the bottom surface of the second pixel defining layer between them, that is, the width between points B1 and B2.
  • d4 1 In the direction from the second sub-pixel to the first sub-pixel (that is, in the leftward direction), relative to the top surface of the light-emitting unit of the first sub-pixel and the first sub-pixel and the second sub-pixel.
  • the displacement of the orthographic projection of the boundary B2 of the second pixel-defining layer between the cells on the base substrate is d4 1 .
  • d4 1 can be a negative value, which means that B1 can also be on the left side of A1.
  • the top surface of the light-emitting unit of the second sub-pixel and the first sub-pixel and the second sub-pixel The orthographic projection of the boundary A2 of the first pixel definition layer between the light emitting units of the pixel on the base substrate, the bottom surface of the second wavelength conversion unit and the wavelength conversion of the first sub-pixel and the second sub-pixel
  • the displacement of the orthographic projection of the boundary B2 of the second pixel-defining layer between the cells on the base substrate is d4 2 .
  • the present disclosure determines the size of the first pixel defining layer and the second pixel defining layer between adjacent sub-pixels according to the proportion of different light emitting angles of the light emitting unit and the brightness change rate of the wavelength conversion unit to the light emitting unit, and then controls the size of the adjacent sub-pixels. Subpixel crosstalk.
  • those that may cause crosstalk to the sub-pixel b are those that can reach the wavelength conversion unit 11b from the light-emitting surface of the light-emitting unit 11a through the transparent spacer layer. of those lights.
  • the present disclosure controls the amount of such light to a degree that does not significantly affect the display of the sub-pixel b.
  • the point on the bottom surface of the wavelength conversion layer 11b closest to point A1 on the top surface of the light emitting unit 31a is its left end point B2, that is, the right end of the bottom surface of the second pixel defining layer, or the bottom surface of the wavelength conversion unit and the first point Two pixels define the border of the layer.
  • the incident angle and the outgoing angle refer to the included angle with the normal line, within the range of 0-90°, and the incident and outgoing angles are relative to the interface.
  • the above critical angle is determined according to the intensity distribution of the light emitting angles of the light emitting unit. By making the above-mentioned critical angle satisfy "the proportion of the incident light amount greater than the critical angle is lower than the threshold", the brightness of cross-color can be controlled to be small enough, so as to actually solve the problem of cross-color.
  • the aforementioned threshold is determined by the correlation of the luminance change rates of the wavelength conversion units of the first sub-pixel and the second sub-pixel.
  • the display effect of a sub-pixel of a display device is related to its luminous intensity and the human eye's ability to perceive its luminous wavelength, which is comprehensively expressed as its brightness. Referring to FIG. 6(b), when x1% of the light emitted by A1 to the right and reaches the top surface of the transparent spacer layer may reach the second sub-pixel adjacent to the right, the second sub-pixel may be caused by color crossover.
  • the ratio of the luminance of the first sub-pixel itself to the luminance of the light-emitting unit is x1% ⁇ rb
  • the ratio of the luminance of the first sub-pixel itself caused by the light emitted from point A1 to the left to the luminance of the light-emitting unit is ra
  • ra and rb are respectively the brightness conversion ratios of the first sub-pixel and the second sub-pixel to the light of the light-emitting unit.
  • the cross-color light emission in the second sub-pixel has a luminance ratio of x1% ⁇ rb/ra, which can be expressed as x1% ⁇ (rb/ra).
  • the critical value p1 may be more preferably 3.1% or less, and still more preferably 2% or less.
  • the part of total reflection needs to be removed.
  • the incident angle of the sub-layer with a refractive index of 1.8 to the sub-layer with a refractive index of 1.5 is greater than about 52 ° of light will be totally reflected.
  • the corresponding critical angle and the like can be calculated according to the total light intensity corresponding to the initial incident light in the range of 0 to 52° in the layer. The light intensity with an incident angle greater than 52° will not affect the wavelength conversion layer because it does not reach the top surface of the transparent spacer layer, so it will not be considered in the calculation of the critical geometric parameters.
  • the proportion of the light intensity from point A1 to point B2 is limited to be below the critical value x1%, the problem of cross-color can be effectively eliminated.
  • the lateral distance from the incident point to the exit point needs to be less than or equal to d2+d4 2 , That is, the sum of the distance from A1 to A2 and the lateral distance from A2 to B2.
  • d4 2 can also be a negative value.
  • the intensity of light with an exit angle larger than ⁇ 1 accounts for less than x1%.
  • the design idea of the present disclosure is as follows. First, determine the change coefficient of the wavelength conversion unit (or transparent color-resist unit) of two adjacent sub-pixels to the luminance of the light-emitting unit. Second, considering the ratio of the light emitted from the light-emitting unit of a sub-pixel to the adjacent sub-pixel and the current sub-pixel, the adjacent sub-pixel can produce enough brightness to display cross-color. In this process, the above-mentioned luminance change coefficient is taken into consideration, and the luminance ratio sufficient to display cross-color is set as the critical ratio p obtained by simulation. Finally, the upper limit x% of the proportion of light reaching adjacent sub-pixels that should not exceed is calculated.
  • the critical emission angle ⁇ at the bottom surface of the transparent spacer layer corresponding to these proportions of light it is stipulated that the amount of light with an emission angle greater than ⁇ is the above upper limit x%. That is, a lower limit of the outgoing angle is calculated, and it is necessary to prevent light whose outgoing angle is smaller than the lower limit from reaching adjacent sub-pixels.
  • the value of the critical exit angle ⁇ corresponding to the intensity ratio of the light greater than a certain value can be measured by experiment or calculated by modeling.
  • the inventors have found that the intensity of light entering the transparent spacer layer from the light-emitting unit at its interface with the transparent spacer layer can vary as a function of angle.
  • the light intensity is the highest when the exit angle is 0° (that is, the normal direction), and the intensity is close to zero when the exit angle is close to 90°, and the relationship between the intensity and the angle may not be monotonously increasing or decreasing.
  • Fig. 7 exemplarily shows an output angle-light intensity curve.
  • the above threshold can be calculated according to the ratio of the area under the calculated curve in the output angle-light intensity curve.
  • the critical angle can be determined from the threshold.
  • the output angle-light intensity curve can be measured experimentally, or modeled and calculated.
  • the light intensity ratios of the light field distribution shown in Figure 7 at some angles above 60° are shown in the table below.
  • Figure 7 and the above table show only one exemplary light field distribution.
  • the specific light field distribution may be different from that shown in FIG. 7 .
  • the dimensions of the encapsulation structure layer, the first pixel defining layer, and the second pixel defining layer in FIG. 6(b) should also ensure that the cross-color influence of the second sub-pixel on the first sub-pixel is controlled. For this reason, when the light with an exit angle of ⁇ 2 emerges on its top surface, the lateral distance between the exit point and the incident point is no greater than d2+d4 1 , wherein the light emitted by the light-emitting unit is incident on the interface, and the exit angle
  • a critical value p2 is chosen, which is a value of ⁇ 5%.
  • the aforementioned conditions only limit the sum of d2 and d4 2 or the sum of d2 and d4 1 , but there is no requirement for the proportion of d2 in d2+d4 2 .
  • the size of the first pixel defining layer is designed first, and then the size of the second pixel defining layer is further designed. In other words, after d2 is determined first, then d4 1 and d4 2 are determined on the basis of d2. In the implementation shown in FIG. 6( b ), the bottom of the second pixel-defining layer is wider than the top of the first pixel-defining layer, and thus d4 1 and d4 2 are positive values.
  • d4 1 and d4 2 can also be negative, corresponding to the case where the bottom of the second pixel-defining layer is narrower than the top of the first pixel-defining layer. In other embodiments, d4 1 and d4 2 can be substantially zero.
  • the second pixel defining layer and the center of the first pixel defining layer are aligned, so d4 1 and d4 2 are equal.
  • the critical value of d4 1 and d4 2 should meet the requirement that the intensity ratio of the light whose exit angle is above ⁇ 1 is less than x1%, and that the exit angle is above ⁇ 2 The intensity ratio of the light above is x2% or less.
  • the larger of the critical values of d4 1 and d4 2 can be used in the sub-pixels on both sides at the same time to achieve a symmetrical design.
  • x1>x2 should be, that is, the upper limit of the proportion of light above the exit angle ⁇ 1 can be greater than the upper limit of the proportion of light above the exit angle ⁇ 2 , that is, ⁇ 1 ⁇ ⁇ 2 , correspondingly, the critical value ratio of d4 1
  • the critical value of d4 2 is large.
  • d4 2 can also be set according to the critical value of d4 1 , so that the value of the lateral propagation distance of the optical path meets the requirements of preventing the second sub-pixel from cross-coloring to the first sub-pixel, and at the same time, the lateral propagation distance of the optical path also naturally meets the requirement of preventing the first sub-pixel from cross-coloring. A requirement for color crossing from a sub-pixel to a second sub-pixel.
  • d4 1 and d4 2 may be different.
  • the size range can be extended to
  • Figure 8 shows a schematic light path in an exemplary transparent spacer layer. Its four layers are respectively L1 to L4 from bottom to top.
  • L1 may be an ITO cathode layer, on which the first inorganic layer, the organic layer, the second inorganic layer, etc. are sequentially covered. Their refractive indices are n1 to n4, respectively.
  • Transverse optical path d L1 tan ⁇ 1 +L2 tan ⁇ 2 +L3 tan ⁇ 3 +L4 tan ⁇ 4 . Therefore, by specifying ⁇ 1 as ⁇ 1 determined by x1 or ⁇ 2 determined by x2, the geometric relationship between the first sub-pixel and the second sub-pixel can be calculated, thereby completing the structural design.
  • the transparent spacer layer and its specific sub-layer composition can be selected according to the relationship according to the present disclosure.
  • the thickness of the transparent spacer layer is d1
  • the transparent spacer layer includes m sublayers stacked from bottom to top
  • the thickness and refractive index of the i-th sublayer are Li and ni , i from 1 to m
  • i is an integer from 1 to m
  • the lateral advancing distance of the optical path is the sum of the advancing distances in each sub-layer.
  • the distance of advancement in each sublayer is related to the exit angle of each light entrance interface and the thickness of the sublayer.
  • the exit angle of each light incident interface is related to the refractive index of the sub-layer and the previous sub-layer.
  • d2+d4 2 can be calculated as above; for the exit angle of ⁇ 2 , d2+d4 1 can be calculated similarly; for the exit angle of ⁇ 3 described below, d5+d4 3 can be calculated similarly ;and many more.
  • the thickness of the metal transparent cathode is much smaller relative to the inorganic/organic encapsulation layer on it.
  • the thickness of the metal transparent cathode is usually tens of nanometers at most, and the scale of the encapsulation layer on it is in the order of microns. Therefore, in the calculation of the above formula in the present disclosure, the existence of the metallic transparent cathode can be ignored.
  • the thickness of the metal transparent cathode and the lateral progress of light in it are not counted.
  • the light emission angles ⁇ 11 and ⁇ 12 are calculated from the top surface of the metal transparent cathode as the interface.
  • the travel of light in them should not be neglected.
  • the sub-pixels arranged in an array further include a third sub-pixel, the first sub-pixel is adjacent to the third sub-pixel, and in the third sub-pixel, a a light-emitting unit in the light-emitting layer and a transparent color-resist unit in the wavelength conversion layer, the light-emitting unit and the transparent color-resist unit are stacked and separated by the transparent spacer layer,
  • the light-emitting units of the first sub-pixel and the third sub-pixel are separated by the first pixel-defining layer in the light-emitting layer, and the distance between the top surfaces is d5,
  • the transparent color-resist unit does not perform wavelength conversion on the light emitted by the light-emitting unit and has a brightness change rate of rc, the wavelength conversion unit of the first sub-pixel and the transparent color-resist unit of the third sub-pixel are determined by the separated by a second pixel defining layer in the wavelength conversion layer,
  • the projection length of the light path passing through the transparent spacer layer on the base substrate is less than or equal to d5+d4 3 .
  • the wavelength conversion layer of the present disclosure may also have a transparent color resist unit.
  • the sub-pixels with the transparent color-resist unit are used to make the light emitted by the light-emitting unit be emitted directly without wavelength conversion.
  • the mutual color crossover between the two is as follows.
  • FIG. 9 schematically shows the structure between two adjacent sub-pixels c and a in an embodiment of the present disclosure.
  • the first sub-pixel a includes a light-emitting unit 31a and a wavelength conversion unit 11a
  • the third sub-pixel c includes a light-emitting unit 31c and a wavelength conversion unit 11c.
  • Components such as the transparent spacer layer, the light emitting unit, the first pixel defining layer and the second pixel defining layer in FIG. 9 are similar to those in FIG. 6 .
  • the difference from FIG. 6(f) is that the light from point A3 of the first sub-pixel to point B4 enters the transparent color-resist unit 11c. Since the transparent color-resist unit 11c does not have wavelength conversion particles, even if it contains scattering particles, the light from point A3 of the first sub-pixel to point B4 will not obviously emit light on the front of the display panel. In other words, the cross-color level from the first sub-pixel to the third sub-pixel without wavelength conversion is negligible and does not need to be limited by special geometric parameters. In this case, the distance d4 to 4 may not be specifically limited. Of course, d4 4 can also be limited by adopting the idea of the present invention based on relative brightness.
  • the transparent color-resist unit does not convert the wavelength of the light emitted by the light-emitting unit, but the brightness of the material will still change due to the brightness change rate of the material, wherein the brightness change rate is rc. rc is a value that is always less than 100%.
  • the corresponding critical light leakage intensity ratio from the light-emitting unit 31c of the third sub-pixel to the wavelength conversion unit 11a of the first sub-pixel can be calculated from p, ra, rc Critical exit angle ⁇ 3 .
  • the preferred range of the relative brightness threshold value of the anti-crosstalk is the same as above.
  • the width of the top surface of the pixel-defining layer between each sub-pixel is equal, because usually the light-emitting units are all of the same size and size and evenly distributed.
  • the specific geometric structure of each layer in the display panel with sub-pixels of three colors can be designed.
  • the light-emitting unit emits blue light
  • the third sub-pixel includes a transparent color-resisting unit and is a blue sub-pixel
  • the first sub-pixel is a red sub-pixel
  • the second sub-pixel is a green sub-pixel, respectively. sub-pixels and green sub-pixels, thus RGB color display can be realized.
  • the brightness change rate of the transparent color-resist unit is [60%, 85%].
  • ra is in [110%, 180%] and rb is in [25%, 70%].
  • the brightness change rate is related to parameters such as the emission wavelength, the converted wavelength, and the external quantum efficiency of the photoluminescent material, and the range of change is relatively large.
  • the brightness change rate of blue light to green light is in the range of 25% to 70%
  • the brightness change rate of blue light to red light is in the range of 110% to 180%. Based on such a range, x1 and x2 can be calculated, and then ⁇ 1 and ⁇ 2 can be calculated, and then the required d2+d4 1 and d2+d4 2 can be calculated.
  • the brightness change rate of the red light quantum dots may be about 40%, and the brightness change rate of the green light quantum dots may be about 170%.
  • the luminance change rate of the red light quantum dots may be about 23%, and the luminance change rate of the green light quantum dots may be about 110%.
  • the brightness change rate of the red sub-pixel may be about 120%
  • the brightness change rate of the green sub-pixel may be about 60%
  • the brightness change rate of the transparent color-resist unit or light-scattering unit may be about 80%. %.
  • the brightness change rate of the transparent color-resist unit or light-scattering unit may be about 80%. %.
  • the angle corresponding to ⁇ 1 is about 76°
  • the angle corresponding to ⁇ 2 is about 82°.
  • the minimum value of d4 1 will be greater than the minimum value of d4 2 .
  • the lateral distance between the top surface of the light-emitting unit of all sub-pixels and the bottom surface of the wavelength conversion unit or transparent color-resisting unit of the adjacent sub-pixel can be set to d2+d4 1 corresponding to 82° .
  • d2+d4 1 corresponding to 82° .
  • the design of the present disclosure can also be used in adjacent sub-pixels of the same color.
  • adjacent sub-pixels of the same color are arranged in the Y direction in FIG. 1 .
  • the crosstalk between sub-pixels of the same color will not cause color changes, it will also affect the display.
  • FIG. 10 shows a section in the YZ plane of FIG. 2 . Since two adjacent sub-pixels a1 and a2 have the same color, d4 5 and d4 6 may be equal.
  • the equivalent conversion rate is equal.
  • the conversion ratios of adjacent sub-pixels are also equal.
  • the critical light intensity proportions are equal for both the first and second sub-pixels.
  • the ratio can be selected to be slightly larger, for example, 5%, but the aforementioned range up to p and the preferred range can also be selected.
  • the parameters between the first sub-pixels and between the second sub-pixels are the same.
  • the geometric structure therebetween may not be limited, but the size is preferably the same as that of the first and second sub-pixels.
  • the wavelength converting unit comprises quantum dots.
  • the wavelength conversion unit may be a quantum dot wavelength conversion unit.
  • the light emitting unit is an OLED.
  • a QD-OLED display panel is formed.
  • the transparent spacer layer includes, from bottom to top, a first inorganic layer, an organic layer, and a second inorganic layer.
  • the inorganic-organic-inorganic transparent spacer layer can be used as an encapsulation layer for encapsulating the light-emitting layer, providing good comprehensive mechanical properties and protection against the outside world, and providing a barrier for the subsequent second pixel definition layer, wavelength conversion layer or transparent layer.
  • the preparation provides the substrate, or is used to prepare the cassette with a separately prepared wavelength conversion layer.
  • the first inorganic layer may be a SiNx layer
  • the second inorganic layer may be a SiONx layer or an Al2O3 layer.
  • a good encapsulation effect can be achieved by interposing an organic layer between such a first inorganic layer and a second inorganic layer.
  • the material selection and thickness of the inorganic layer can be adjusted appropriately, and the protection, thickness and strength of the inorganic layer should be taken into consideration.
  • An organic layer typically has a low index of refraction relative to the inorganic layers above it and causes light rays to travel at large angles within it, resulting in a large optical path length required. Reducing the thickness of the organic layer is beneficial to reduce the distance between adjacent sub-pixels, thereby improving the resolution.
  • the transparent cathode covers the first pixel defining layer as a common electrode. It should be understood that there may be electron injection layer, electron transport layer, hole blocking layer and other film layers between the transparent cathode and the light emitting material layer of the light emitting unit. If these film layers are entirely formed on the first pixel defining layer, they can also be part of the transparent spacer layer. If these film layers are formed between the first pixel defining layers, they belong to a single light emitting unit.
  • the transparent cathode can be used for the transparent cathode.
  • the thickness of the metal transparent cathode is much smaller than that of the transparent spacer layer, so its existence can be ignored in the calculation of the transverse optical path distance based on the above-mentioned refractive index and film thickness.
  • the thickness of the organic layer is in the range of 4 to 8 ⁇ m. Such a thickness is lower than the conventional thickness in the related art, which is beneficial to reduce the optical path.
  • An organic layer of this thickness can be formed, for example, by inkjet printing. Under such a thickness, according to the principles of the present disclosure, a display panel with no color crossover and higher resolution can be obtained.
  • the thickness of the organic layer is in the range of 0.3 to 0.6 ⁇ m. Such a thickness is greatly reduced compared with the related art, which is conducive to greatly reducing the optical path and greatly improving the resolution.
  • Such thin organic layers can be prepared, for example, by molecular layer deposition.
  • the first inorganic layer is SiN with a thickness ranging from 0.6 to 1.2 ⁇ m
  • the organic layer is an organic filled layer with a thickness ranging from 4 to 8 ⁇ m
  • the second inorganic layer is SiN with a thickness ranging from 0.6 to 1.2 ⁇ m. ⁇ m SiON.
  • the first inorganic layer is SiN with a thickness in the range of 0.4 to 0.7 ⁇ m
  • the organic layer is an organic layer with a thickness in the range of 0.3 to 0.6 ⁇ m
  • the second inorganic layer is SiN with a thickness in the range of 0.7 to 0.7 ⁇ m. 1.3 ⁇ m Al 2 O 3 .
  • the bottom of the second pixel defining layer is used to define the bottom surface of the wavelength conversion unit or the transparent color resist unit.
  • FIG. 11 shows several common schematic shapes of the second pixel defining layer, including substantially regular trapezoidal, substantially rectangular and substantially inverted trapezoidal.
  • a positive trapezoid means that the side closer to the substrate is longer, and an inverted trapezoid means that the side closer to the light-emitting side is longer.
  • the second pixel defining layer may also be asymmetrical, but from the viewpoint of preparation convenience, a symmetrical second pixel defining layer is preferred.
  • the boundary of its interface with the transparent spacer layer is its boundary with the wavelength conversion units or transparent color resist units on both sides, and defines their bottom surfaces.
  • the width of the top surface of the second pixel defining layer is smaller than the width of the bottom surface thereof.
  • the light emitting surface of the wavelength conversion layer between the second pixel defining layers is larger than the light incident surface, which is beneficial for display.
  • the second pixel defining layer of the present disclosure may include a main body and a cladding layer on a sidewall of the main body.
  • the additional cladding of the main body can bring various advantages to the wavelength conversion unit.
  • FIG. 12 shows a schematic diagram of a second pixel defining layer with a sidewall cladding layer on the sidewall.
  • Wavelength conversion layers such as QD wavelength conversion layers are often prepared by inkjet printing.
  • On EL route it is necessary to make a low-temperature-cured second pixel definition layer pattern on the encapsulation layer. This is because the light-emitting unit is not resistant to high temperatures. When the temperature exceeds 100°C, problems such as reduced luminous efficiency and lifetime will occur. .
  • the second pixel-defining layer material cured at low temperature there are still a large number of gaps and holes inside, causing ink to permeate easily, and one pixel penetrates into another pixel, causing color mixing, and due to ink penetration, the second pixel A swelling effect will occur in the limiting layer, and the overall width will decrease, resulting in a decrease in the pixel aperture ratio.
  • an ink penetration protection layer can be arranged on the side wall of the original second pixel defining layer.
  • the second pixel defining layer includes a main body and an ink penetration prevention layer disposed on a side thereof.
  • the coating may also be a reflective layer, including reflective material.
  • the coating can also be a light-absorbing layer, including light-absorbing materials (such as metal molybdenum; or resin mixed with black pigments, wherein the black pigments can be one or more of nigrosine black, perylene black, titanium black, carbon black, and metal oxides. 1)
  • the existence of the reflective layer can make the unconverted light and the converted light incident on the side wall of the second pixel defining layer enter the wavelength conversion unit again, thereby enhancing the light extraction efficiency.
  • the light-reflecting material or the light-absorbing material is formed on the top surface of the transparent spacer layer to form a laterally extending portion as described below, it can shield light.
  • the cladding material is a metal layer.
  • the structure of the metal layer is relatively dense, which can block solvents and has a reflective effect.
  • the metals used include but are not limited to Al, Ti/Al/Ti, Mo, etc., which have excellent compactness and light reflection or light absorption for blocking ink solvents.
  • the cover layer has a lateral extension away from the main body portion at the bottom covering the surface of the transparent spacer layer.
  • FIG. 13 shows a schematic view of a structure with an epitaxial cladding on the bottom. It can be seen that the ink penetrates the protective layer, which may also be a reflective layer, at the bottom to expand the width of the second pixel defining layer.
  • the advantages of this design include the following two points.
  • the width of the bottom of the second pixel defining layer is increased as much as possible in order to avoid cross-color, the upper end of the second pixel defining layer will become wider accordingly, so that the wavelength conversion layer
  • the light-emitting area is relatively reduced, or the volume of the wavelength conversion layer is reduced, and this L-shaped cladding can make the wavelength conversion layer have a larger volume under the same light-incidence surface, so that the wavelength conversion is more sufficient. It has a relatively larger light emitting area and will not affect the resolution.
  • this L-shaped coating is an ink penetration protection layer, it will enhance the protection of the bottom of the main body, making it more difficult for ink to penetrate the relatively weak bottom.
  • the main body portion has an undercut, and the cladding layer not only covers the sidewall, but also covers the top surface of the transparent spacer layer at the undercut, as shown in the right diagram of FIG. 13 .
  • the undercut means that the bottom of the second pixel defining layer is concave relative to the top, wherein the bottom is the side close to the base substrate, and the top is the side away from the base substrate.
  • the shape of an inverted trapezoid has an undercut.
  • the top corners of inverted trapezoids are often not sharp corners, but rounded corners, and even form the aforementioned "mushroom-shaped" cross-section in actual production, the two upper corners are rounded, and the depth of undercut at the root may be different. reduce. It should be noted that, if the process allows, the deviation of the product from the trapezoid should be avoided as far as possible, that is, the standard trapezoid is more ideal.
  • the advantage of the L-shaped ink penetration protection layer disposed in the undercut is that it can be conveniently prepared on the low-temperature cured second pixel defining layer by sputtering followed by dry etching.
  • the second pixel defining layer is prepared by the following method: photocuring to obtain a main body with undercuts, sputtering deposition of a covering protective layer, and then removing the protective layer on the top surface of the main body and the undercut parts by dry etching. protective layer.
  • Figure 14 shows a SEM photograph of the metal ink penetration barrier with undercuts and sidewalls.
  • the metal ink penetration protection layer is an aluminum layer
  • the thickness of the aluminum layer in Figures (a)-(d) is and It can be seen that the thickness of metal Al is After dry etching, the thickness of Al is different, and the shape of the reflective metal left on the sidewall of the second pixel defining layer and the range of shielding are also different.
  • Al thickness selection A good fit, other metals follow the same range.
  • the reflectivity of visible light is: Ti/Al/Ti>Al>Mo, but because Al is easily oxidized to Al 2 O 3 , the reflectivity is reduced, so the material is preferably Ti/Al/Ti or Ti metal .
  • the undercut depth is in the range of [4 microns, 9 microns].
  • the undercut depth is the difference between the projection distances of the edge of the top surface and the edge of the bottom surface on the substrate, such as the distance u between the arrows in the right figure of FIG. 13 .
  • Such an undercut depth can be formed by photocuring.
  • the included angle between the side surface and the bottom surface is preferably between 95° and 140°. Such an angle maintains the strength of the body portion and leaves the right amount of space for the ink penetration barrier at the undercut.
  • the display panel forming process may include a cell-to-cell method and an on-EL method.
  • the cell-to-cell method refers to forming the light-emitting layer and the wavelength conversion layer separately, and then assembling the two in a cell.
  • the on-EL method is to continue to prepare the wavelength conversion layer layer by layer on the basis of the light-emitting layer.
  • the display panel of the present disclosure may use these two forming processes simultaneously.
  • the manufacturing process of the wavelength conversion unit/transparent color resist unit may include inkjet printing and photolithography.
  • the shapes in the cross-sectional view are all rectangles or trapezoids.
  • the top surface of the first pixel defining layer is a plane, and the top surface of the light-emitting unit between them is a plane flush with it; the bottom surface of the second pixel defining layer is a plane, and the wavelength conversion unit between them The bottom surface is a plane flush with it; the bottom and top surfaces of the transparent spacer layer are also planes accordingly.
  • the sidewalls of these structures are also flat.
  • the above-mentioned surfaces may not be ideal planes, and the side walls of these structures may also be uneven. However, these faces should not have excessive undulations. In cases where these surfaces have only minor undulations relative to the ideal shape, the aforementioned parameters are determined after fitting their surfaces to planes.
  • the present disclosure also provides a display panel including a color filter layer.
  • the display panel of the present disclosure may also include a color filter layer to provide better color display effect.
  • the color filter layer is arranged on the wavelength conversion layer. For example, red, green, and blue filter units are set for corresponding positions of the red, green, and blue sub-pixels.
  • FIG. 15 shows a schematic structural view of an embodiment of the QD-OLED display panel of the present disclosure further comprising a color filter layer.
  • the wavelength conversion layer 3 is also covered with a color filter layer 6 and an outer protective encapsulation layer 5 .
  • the color filter layer 4 may include a black matrix BM and various color filters defined by the BM.
  • 31 is an OLED light-emitting unit
  • 11R and 11G are red and green wavelength conversion units
  • 11B is a transparent color resistance unit
  • 61R, 61G and 61B are red, green and blue color filters.
  • the transparent spacer layer 2 may include an encapsulation layer for the light-emitting layer and an encapsulation layer for the wavelength conversion layer, and may also include a filler layer and a support column structure between the light-emitting layer and the wavelength conversion layer.
  • the encapsulation layer facilitates its cell-to-cell assembly.
  • FIG. 15 is only intended to illustrate the mutual positional relationship of each component, and does not limit the specific shape and details of each component.
  • Fig. 16 shows an embodiment of a light-emitting layer-related structure.
  • the figure shows a partial schematic diagram including 3 complete OLED light-emitting units and 4 PDL-1s.
  • the base substrate BS has a buffer layer BUF on it.
  • a TFT unit is configured for each sub-pixel.
  • the TFT unit includes a source S, a drain D, a gate G, and an active layer ACT.
  • An interlayer dielectric layer ILD and a planarization layer PLN are arranged in sequence above the second gate insulating layer.
  • Enable signal lines Ce1 and Ce2 are also arranged between the second insulating layer and the interlayer dielectric layer.
  • a light emitting unit is formed between the first pixel defining layer PDL-1.
  • the light emitting unit includes an anode AD, an organic light emitting part EL, and a cathode CD from the bottom side to the top side.
  • the anode is connected to the drain of the TFT, and the cathode is a common electrode.
  • the first encapsulation layer Encap-1 Above the cathode, there is also the first encapsulation layer Encap-1.
  • the first encapsulation layer is located on the side of the light-emitting layer close to the wavelength conversion layer. As shown in FIG.
  • PDL-1 is a wall with a trapezoidal longitudinal section. It should be understood that it forms a grid on the array substrate and defines many spaces for arranging the light emitting units.
  • the structure of the above-mentioned OLED light-emitting unit is known in the art, which includes an anode, an organic light-emitting layer, a cathode, and the like.
  • the anode AD of the light emitting unit may be a reflective anode, which reflects the light emitted by the OLED to the top surface, so as to increase the light extraction efficiency.
  • the light-emitting layer of the present disclosure has only one color of light-emitting material layer, so it can be formed using an Open Mask without using, for example, a fine metal mask to form sub-pixels one by one.
  • the projection of the TFT on the base substrate can overlap with both the PDL-1 and the light emitting unit. That is, the TFT may also be partly placed under the PDL-1 and another part under the reflective anode.
  • the present disclosure provides a method for preparing the above display panel, wherein the second pixel defining layer is prepared through the following steps:
  • the coating on the top surface of the main body and the coating on the portion of the transparent spacer layer that is not shielded by the top surface of the main body are removed by dry etching, leaving the side walls of the main body and the undercuts in the undercut. the cladding.
  • the "L"-shaped cladding layer schematically shown in the right figure of FIG. 13 can be easily obtained through the above-mentioned sputtering-dry etching method.
  • metals such as Al, Ti/Al/Ti, and Mo are deposited on the second pixel defining layer by sputtering at room temperature, and then vertically etched by dry etching.
  • the inverted trapezoidal sidewall can provide Effective shielding allows the metal on the side wall to remain, and the top of the inverted trapezoid and the metal in the pixel are etched away.
  • the top of the inverted trapezoid has no metal to prevent reflections on ambient light.
  • hydrogen fluoride plasma bombardment is carried out to modify the surface of the top of the second pixel defining layer, so that it has a hydrophobic and oleophobic surface property, which is convenient for the subsequent printing process.
  • the undercut body portion is obtained by low temperature curing of a black material.
  • the wavelength conversion layer is directly formed on the substrate of the light-emitting layer and the transparent spacer layer. Therefore, in order not to damage the underlying light-emitting unit due to high temperature, it is advantageous to use a low-temperature cured second pixel defining layer.
  • due to the low curing temperature of materials cured at low temperature there are still a large number of gaps and holes inside, so the ink is prone to permeation during the inkjet printing process, and one pixel penetrates into another pixel, resulting in color mixing.
  • the material of the second pixel defining layer will undergo a swelling effect and become wider overall, resulting in a decrease in the pixel aperture ratio.
  • the bottom of the material is poorly cured due to the black blocking of light, thereby naturally forming an undercut.
  • the undercut facilitates the formation of an L-shaped coating, and after the L-shaped coating is formed, it can effectively block ink penetration.
  • the use of low-temperature curing black material to obtain the main body with an undercut not only protects the light-emitting unit, but also facilitates the preparation of an L-shaped coating to overcome the problem of pores.
  • the edge of the L-shaped cladding layer in the undercut that is, the boundary of the wavelength conversion unit, can be easily defined by the top width of the second pixel definition layer itself in the dry etching process, without the need for high-precision mask and other patterning means . This avoids the problem that the lateral extension distance of the L-shaped coating in FIG. 13 is not easy to control.
  • said transparent spacer layer comprises an organic layer, said organic layer being prepared by molecular layer deposition.
  • molecular layer deposition much thinner organic layers can be obtained compared to coating or inkjet printing. Since the refractive index of organic materials is generally low, an ultra-thin organic layer can significantly reduce the lateral optical path of light in the light path emitted by the critical angle described in the present disclosure, so that the bottom surface of the second sub-pixel can be narrower, thereby obtaining higher resolution.
  • the present disclosure also provides a display device comprising the display panel of the present disclosure, which can have good anti-cross-color performance.
  • the device prepared in this series of embodiments is a blue OLED superimposed QD wavelength conversion unit structure, On EL type route, the TFT, light-emitting unit and QD wavelength conversion unit are fabricated on a substrate, the packaging layer of the light-emitting unit in this embodiment It is a three-layer packaging structure, about 10 ⁇ m.
  • the stacked structure of the backplane is TFT layer, PNL layer, anode ITO/Ag/ITO layer, first pixel definition layer, blue light emitting layer, cathode layer, thin film encapsulation layer, low temperature second pixel definition layer, second pixel definition layer Layer side wall reflective metal layer, QD wavelength conversion unit layer, low temperature color filter layer, low temperature OC layer, white glass cover plate.
  • the substrate substrate is cleaned by standard methods; and the TFT process is prepared;
  • a layer of ITO/Ag/ITO is deposited by sputtering with a thickness of Coating a layer of photoresist material by spin coating; patterning the ITO/Ag/ITO layer through pre-baking, exposure, development, wet etching and other process conditions;
  • the MgAg cathode layer was prepared using sputtering equipment 80 to
  • IJP to print R/G QD Ink materials and B pixel scattering particle Ink materials; adjust the process conditions such as pre-baking, exposure, development, and post-baking, with a thickness of 10 to 12 ⁇ m; the brightness conversion rate of red and green QD layers to blue light The ratio is 2:1;
  • Coat low-temperature RGB CF materials by spin coating adjust the process conditions such as pre-baking, exposure, development, and post-baking, and the thickness is 2 ⁇ m;
  • the optical path is calculated according to the refractive index of each layer of the encapsulation layer and the total reflection part is removed.
  • the light intensity with an exit angle between 51° and 52° accounts for about 1.55% of the total light intensity between 0° and 52°.
  • the exit angle is about 80°, which moves 45.4 ⁇ m laterally in the organic layer with a thickness of 8 ⁇ m.
  • the exit angle becomes 55°, and it moves laterally by 1.4 ⁇ m in SiNx with a thickness of 1 ⁇ m. Therefore, the total lateral movement distance is calculated to be 48 ⁇ m, which is less than the bottom width (50 ⁇ m) of the second pixel defining layer, and cannot reach the wavelength conversion unit of the adjacent sub-pixel.
  • the prevention of cross-color can be realized in a structure without an additional vertical light-blocking layer.
  • the device prepared in this series of embodiments is a blue OLED superimposed QD wavelength conversion unit structure
  • the TFT, light-emitting unit and QD wavelength conversion unit are fabricated on a substrate, the packaging layer of the light-emitting unit in this embodiment It is a three-layer packaging structure, about 2 ⁇ m.
  • This structure uses molecular layer deposition and atomic layer deposition equipment to make the film layer denser. While ensuring reliability, it optimizes and thins the EL packaging layer. According to the previous dimension design calculation, compare Embodiment 1, this embodiment can increase the designed aperture ratio by more than 60%.
  • the stacked structure of the backplane is TFT layer, PNL layer, anode ITO/Ag/ITO layer, first pixel definition layer, blue light emitting layer, cathode layer, thin film encapsulation layer, low temperature second pixel definition layer, second pixel definition layer Layer side wall reflective metal layer, QD wavelength conversion unit layer, low temperature color filter layer, low temperature OC layer, white glass cover plate.
  • the substrate substrate is cleaned by standard methods; and the TFT process is prepared;
  • a layer of ITO/Ag/ITO is deposited by sputtering with a thickness of Coating a layer of photoresist material by spin coating; patterning the ITO/Ag/ITO layer through pre-baking, exposure, development, wet etching and other process conditions;
  • the MgAg cathode layer was prepared using sputtering equipment 80 to
  • PECVD molecular layer deposition
  • ALD atomic layer deposition
  • IJP to print R/G QD Ink materials and B pixel scattering particle Ink materials; adjust the process conditions such as pre-baking, exposure, development, and post-baking, with a thickness of 10 to 12 ⁇ m; the brightness conversion rate of red and green QD layers to blue light The ratio is 2:1;
  • Coat low-temperature RGB CF materials by spin coating adjust the process conditions such as pre-baking, exposure, development, and post-baking, and the thickness is 2 ⁇ m;
  • the anti-cross-color effect can be obtained at a good resolution.
  • the device prepared in this series of embodiments is a blue OLED superimposed QD wavelength conversion unit structure, On EL type route, the TFT, light-emitting unit and QD wavelength conversion unit are fabricated on a substrate, the packaging layer of the light-emitting unit in this embodiment It is a three-layer packaging structure, about 10 ⁇ m.
  • the cross-section of the second pixel defining layer is trapezoidal, and this structure is more conducive to light emission.
  • the stacked structure of the backplane is TFT layer, PNL layer, anode ITO/Ag/ITO layer, first pixel definition layer, blue light emitting layer, cathode layer, thin film encapsulation layer, low temperature second pixel definition layer, second pixel definition layer Layer side wall reflective metal layer, QD wavelength conversion unit layer, low temperature color filter layer, low temperature OC layer, white glass cover plate.
  • the substrate substrate is cleaned by standard methods; and the TFT process is prepared;
  • a layer of ITO/Ag/ITO is deposited by sputtering with a thickness of Coating a layer of photoresist material by spin coating; patterning the ITO/Ag/ITO layer through pre-baking, exposure, development, wet etching and other process conditions;
  • the MgAg cathode layer was prepared using sputtering equipment 80 to
  • Print R/G QD Ink material and B pixel scattering particle Ink material by IJP adjust the pre-baking, exposure, development, post-baking and other process conditions, the thickness is 10 to 12 ⁇ m; the brightness conversion rate of red and green QD layers to blue light is different The ratio is 2:1;
  • Coat the low-temperature RGB color film material by spin coating adjust the process conditions such as pre-baking, exposure, development, and post-baking, and the thickness is 2 ⁇ m;
  • the wavelength conversion unit whose top surface width is larger than the bottom surface width can be more conducive to light extraction.
  • the present disclosure provides a display panel having a light-emitting layer, a transparent spacer layer on the light-emitting layer, and a wavelength conversion layer on the transparent spacer layer, wherein according to the brightness change rate of the wavelength conversion unit of adjacent pixels and the transparent spacer
  • the optical path characteristics of the layer can at least partially solve the problem of cross-color of the wavelength conversion display panel by controlling the ratio of the light intensity reaching the wavelength conversion unit of the adjacent sub-pixel within a certain limit.

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Abstract

本公开提供一种显示面板，具有发光层，在发光层上的透明间隔层，和在透明间隔层上的波长转换层，其中，根据相邻像素的波长转换单元的亮度改变率和透明间隔层的光路特性，通过将到达相邻子像素的波长转换单元的光强占比控制在一定限度内，至少部分解决波长转换型显示面板的串色问题。

Description

显示面板、其制备方法和显示装置 技术领域
本公开涉及显示领域，更具体涉及一种显示面板、其制备方法、和一种显示装置。
背景技术
有机发光显示(OLED)作为主流显示技术已占领移动显示市场，在TV等显示应用上也引起了厂商们极大的兴趣。从显示色彩的方式看，OLED技术路线主要分为两种。一种是用发不同颜色光的有机发光材料(如红色发光材料、绿色发光材料和蓝色发光材料)形成不同颜色的子像素，可称为RGB型。RGB型色域高，已占领中小尺寸应用市场。但是，其因为受到精细金属掩模(FMM)工艺的限制而无法大面积化。喷墨打印RGB OLED的RGB型虽是大尺寸OLED的潜在技术，但因为溶液法OLED材料的研发限制，色域值不够高。另一种是采用单色OLED作为背光发光单元配合彩膜实现彩色显示，可称为背光-彩膜型。由于可采用开口掩模(open mask)整面蒸镀，白色背光配合彩膜的方式已是大尺寸OLED的主流技术之一。在白色背光-彩膜技术中，彩膜起到滤除白光中所需颜色以外波长的光波的作用。彩膜的色域直接限制了大尺寸OLED产品的色域范围。
已经出现了采用波长转换元件将单色的OLED发出的光变色来实现彩色显示的技术。例如，相关技术中已经提出了用蓝光OLED与QD(量子点)结合的技术，以蓝光OLED作为光源，配合QD将蓝光下转换为红光、绿光，实现彩色显示，称为QD-OLED。
包含波长转换元件的显示面板的发展仍面临许多实际技术挑战。对于包含波长转换元件特别是QD转换层的显示面板，仍存在着改进的需要。
概述
本公开提供一种显示面板，包括：
在衬底基板上的发光层，
在所述发光层上的透明间隔层，和
在所述透明间隔层上的波长转换层，
其中，所述显示面板包括阵列排布的子像素，所述阵列排布的子像素包含相邻的第一子像素和第二子像素，在所述第一子像素和第二子像素中每一个中，包含一个在所述发光层中的发光单元和一个在所述波长转换层中的波长转换单元，所述发光单元与所述波长转换单元是层叠的并且由所述透明间隔层隔开，
所述第一子像素和第二子像素的发光单元由所述发光层中的第一像素限定层隔开，且顶面间距为d2，
所述第一子像素的波长转换单元为第一波长转换单元且对所述发光单元发出的光的亮度改变率为ra，所述第二子像素的波长转换单元为第二波长转换单元且对所述发光单元发出的光的亮度改变率为rb，所述第一子像素和第二子像素的波长转换单元由所述波长转换层中的第二像素限定层隔开，
在从所述第一子像素到第二子像素的方向上，相对于所述第二子像素的发光单元的顶面与所述第一子像素和第二子像素的发光单元之间的第一像素限定层的边界在所述衬底基板上的正投影，所述第二波长转换单元的底面与所述第一子像素和第二子像素的波长转换单元之间的第二像素限定层的边界在所述衬底基板上的正投影的位移为d4 2，
其中，
从所述发光单元顶面入射到所述透明间隔层并且可达到所述透明间隔层的顶面的光中，出射角在α 1以上的光的强度占比为x1％以下，其中，x1％＝p1×(ra/rb)，其中，p1≤5％，
其中，从所述透明间隔层的底面出发的光当出射角为α 1时，穿过所述透明间隔层的光路在所述衬底基板上的投影的长度小于等于d2+d4 2。
可选地，p1≤2％。
可选地，从所述透明间隔层的底面出发的光当出射角为α 1时，穿过所述透明间隔层的光路在所述衬底基板上的投影的长度与d2+d4 2之差小于等于5μm。
可选地，在从所述第二子像素到第一子像素的方向上，相对于所述第一子像素的发光单元的顶面与所述第一子像素和第二子像素的发光单元 之间的第一像素限定层的边界在所述衬底基板上的正投影，所述第一波长转换单元的底面与所述第一子像素和第二子像素的波长转换单元之间的第二像素限定层的边界在所述衬底基板上的正投影的位移为d4 1，
其中，
从所述发光单元顶面入射到所述透明间隔层并且可达到所述透明间隔层的顶面的光中，出射角在α 2以上的光的强度占比为x2％以下，其中，x2％＝p2×(rb/ra)，其中，p2≤5％，
其中，从所述透明间隔层的底面出发的光当出射角为α 2时，穿过所述透明间隔层的光路在所述衬底基板上的投影的长度小于等于d2+d4 1。
可选地，p2＝p1。
可选地，d4 1＝d4 2。
可选地，|d4 1|≤5μm，|d4 2|≤5μm。
可选地，所述透明间隔层的厚度为d1，所述透明间隔层包括由下到上堆叠的m个子层，第i个子层的厚度和折射率分别为L i和n i，i为1至m，
各参数满足：
Figure PCTCN2021096070-appb-000001
Figure PCTCN2021096070-appb-000002
其中i为1至m的整数，n isinθ 1i为常数且θ 11＝α 1。
可选地，所述阵列排布的子像素还包含第三子像素，所述第一子像素与所述第三子像素相邻，在所述第三子像素中，包含一个在所述发光层中的发光单元和一个在所述波长转换层中的透明色阻单元，所述发光单元与所述透明色阻单元是层叠的并且由所述透明间隔层隔开，
所述第一子像素和第三子像素的发光单元由所述发光层中的第一像素限定层隔开，且顶面间距为d5，
所述透明色阻单元对所述发光单元发出的光不进行波长转换并且亮度改变率为rc，所述第一子像素的波长转换单元和所述第三子像素的透明色阻单元由所述波长转换层中的第二像素限定层隔开，
在从所述第三子像素到第一子像素的方向上，相对于所述第一子像素 的发光单元的顶面与所述第一子像素和第三子像素的发光单元之间的第一像素限定层的边界在所述衬底基板上的正投影，所述第一波长转换单元的底面与所述第一子像素的波长转换单元和第三子像素的透明色阻单元之间的第二像素限定层的边界在所述衬底基板上的正投影的位移为d4 3，
其中，
从所述发光单元顶面入射到所述透明间隔层并且可达到所述透明间隔层的顶面的光中，出射角在α 3以上的光的强度占比为x3％以下，其中，x3％＝p3×(rc/ra)，其中，p3≤5％，
其中，从所述透明间隔层的底面出发的光当出射角为α 3时，穿过所述透明间隔层的光路在所述衬底基板上的投影的长度小于等于d5+d4 3。
可选地，所述发光单元发蓝光，所述第三子像素为蓝色子像素，所述第一子像素为红色子像素，第二子像素为绿色子像素。
可选地，ra在[110％，180％]，rb在[25％，70％]，rc在[60％，85％]。
可选地，所述波长转换单元包含量子点。
可选地，所述透明间隔层包括由下至上层叠的第一无机层、有机层和第二无机层。
可选地，所述第一无机层是SiNx层，所述第二无机层是SiONx层或Al 2O 3层，所述有机层是环氧树脂层或聚丙烯酸系树脂层。
可选地，所述有机层的厚度在4至8μm的范围内。
可选地，所述有机层的厚度在0.3至0.6μm的范围内。
可选地，所述第二像素限定层的顶面宽度小于其底面宽度。
可选地，所述第二像素限定层包括主体部和在所述主体的侧壁上的覆层。
可选地，所述覆层是墨水渗透防护层。
可选地，所述覆层包括反光材料或吸光材料。
可选地，所述覆层材料为金属。
可选地，所述覆层在底部处具有覆盖所述透明间隔层表面的离开所述主体部的横向延伸部分。
可选地，所述主体部具有底切，所述覆层的所述横向延伸部分覆盖所述底切。
可选地，所述底切的深度在4至9微米的范围内。
可选地，还包括在所述波长转换层上的彩膜层。
在另一个方面，本公开提供一种制备上述显示面板的方法，其中，所述第二像素限定层通过以下步骤制得：
获得具有底切的主体部；
在所述透明间隔层和主体部表面溅射沉积覆盖覆层；
通过干刻除去所述主体部顶面的覆层和所述透明间隔层上未被所述主体部顶面遮蔽的部分的所述覆层，保留所述主体部侧壁和所述底切中的所述覆层。
可选地，通过低温固化黑色材料获得所述具有底切的主体部。
可选地，所述透明间隔层包含有机层，通过分子层沉积法制备所述有机层。
在又一个方面，本公开提供一种包含上述显示面板或根据上述方法制备的显示面板的显示装置。
附图说明
图1(a)和(b)分别示出了在彩膜层和波长转换层中大角度入射的光的光路示意图。
图2示出了显示面板的相关膜层的局部示意图。
图3示出了图2的虚线框中的子像素在X-Z平面内A-A’位置的截面图。
图4示出了图2中一个包含三个并排子像素的像素中在X-Z平面内A-A’位置的截面图。
图5(a)-(f)示意性说明了层结构的划分。
图6(a)-(b)示意性示出了本公开的原理和一个实施方案中两个相邻子像素和之间的结构。
图7示例性地示出了出一种出射角度-光强度曲线。
图8示出了图6所示的透明间隔层中的示意性光路。
图9示意性示出了本公开的一个实施方案中两个相邻子像素之间的结构。
图10示出了在图2的Y-Z面中的截面。
图11示出了第二像素限定层的示意性形状。
图12示出了侧壁具有墨水渗透防护层的第二像素限定层的示意图。
图13示出了在底部具有外延的墨水渗透防护层的结构的示意图。
图14示出了具有底切和侧壁上的金属墨水渗透防护层的SEM照片。
图15示出了还包含彩膜层的本公开的QD-OLED显示面板的一个实施方案的结构示意图。
图16示出了发光层相关结构的一个实施方案。
具体实施方式
发明人发现，对于包含波长转换元件特别是QD转换层的显示面板，相邻子像素之间的串色问题是一个突出的问题。
相关技术中，将OLED-彩膜型显示面板中的背光从白光发光器件替换为可激发波长转换单元的光如蓝光后，将其彩膜层替换为类似尺寸的波长转换层，从而通过波长转换方式代替滤光方式实现彩色发光。在此基础上，还可以再附加一层彩膜层对波长转换后的彩色光进一步纯色化。应注意，尽管相关技术中有时将波长转换元件也称为彩膜(例如QD彩膜)，但在本公开中，彩膜层特指选择性透过特定波长的光的层。
然而，以QD-OLED为代表的波长转换型显示面板中，显现出明显大于OLED-彩膜型显示面板的不同色子像素串色问题。串色是指一个子像素的发光单元发出的光使相邻的其他子像素显色的现象。串色的结果是与发光子像素相邻的子像素在本不该发光的情况下也产生发光，这在相邻子像素是异色子像素时尤其有害。串色严重时，会明显影响显示质量。当直接将白光OLED-彩膜型显示面板的几何参数用于例如蓝光OLED-波长转换型显示面板时，将出现明显影响显示质量的串色。相关技术中已开始注意到串色问题的发生，但关于其具体成因和解决方式仍在研究之中。
不依赖于任何理论，本公开的发明人出人意料地发现，波长转换型显示面板中，波长转换层中的波长转换机制对串色现象有加强作用。在常规的彩膜层中，即使存在从底面入射的来自相邻子像素的背光，由于入射角度很大，其在进入彩膜层后基本上直线前进，其中一部分入射到彩膜层侧 壁上无法射出彩膜层的出光面，另一部分可能在出光面发生全反射无法射出。即使有小部分可能射出，也因为出射角大而对在显示面板正面观看的显示效果基本没有影响。而且，即使在彩膜中存在用于扩大观看角度的散射粒子的情况下也基本如此，因为散射粒子难以将大部分的入射光以大的偏转角度散射至彩膜层正面。与此相反，在波长转换层中，入射的光在光转换点(例如量子点微粒)处发生光致发光，即重新发光。发出的光的发光角度与入射光角度无关，因此大量光将从正面射出，从而造成比相同几何设计的彩膜型显示面板严重得多的串色现象。
图1(a)和(b)分别示出了在彩膜层和波长转换层中大角度入射的光的光路示意图。图1(a)示出了彩膜层的情况。图中示意性地示出了两个相邻的子像素。图1(a)中，两个相邻的子像素各自包括作为背光层的发光单元31和用于滤光的彩膜51。当彩膜层中不存在散射粒子时，左侧子像素的背光层的发光单元发出的光进入与其相邻右侧子像素的彩膜层的底面后，出射角很大，并随后沿直线前进。路线P1表示其到达彩膜层侧壁，无法出射。路线P2表示其虽到达彩膜层的顶面(即其出光面)，但因全反射无法射出。路线P3表示即使射出，出射角也很大，不会对正面观看造成影响。进而，即使彩膜层中存在散射粒子，其对光路的总体影响也比较有限，不会导致大部分入射的光以小的出射角从出光面射出。因此，在彩膜层型OLED的设计中，只需适当设计尺寸使得来自相邻子像素的背光在彩膜层的入射角度较大，即可基本上解决串色问题。与此不同的是，图1(b)示出了相同尺寸下波长转换层11的情况。由于波长转换层中存在大量波长转换粒子(例如量子点微粒)。与图1(a)中相同的入射光P1、P2和P3在波长转换单元行进途中将不可避免地遇到波长转换粒子。在波长转换粒子处，入射光发生波长转换成为新的发光，其发光方向将不再受到入射角度的限制，并且可以从波长转换单元的正面射出，从而造成串色问题。至少部分由于上述原因，彩膜型OLED显示面板中的设计不能避免波长转换型显示面板的串色问题。
解决该问题的可能方式之一是通过增大子像素之间的间距来避免漏光。不过，相关技术中并未发现将子像素间距增大到何种程度为宜。发明人发现，由于串色现象源于由入射光导致的光致发光，因此一味地增大相 邻子像素的距离并不能彻底避免漏光，同时还可能无谓地降低分辨率。虽然也可能在相邻像素之间增设不透光的竖直阻光层等防止向相邻像素漏光，但这类方式将大大增加工艺难度和材料成本，不利于生产。
为至少部分解决上述问题，本公开提供包括：
在衬底基板上的发光层，
在所述发光层上的透明间隔层，和
在所述透明间隔层上的波长转换层，
其中，所述显示面板包括阵列排布的子像素，所述阵列排布的子像素包含相邻的第一子像素和第二子像素，在所述第一子像素和第二子像素中每一个中，包含一个在所述发光层中的发光单元和一个在所述波长转换层中的波长转换单元，所述发光单元与所述波长转换单元是层叠的并且由所述透明间隔层隔开，
所述第一子像素和第二子像素的发光单元由所述发光层中的第一像素限定层隔开，且顶面间距为d2，
所述第一子像素的波长转换单元为第一波长转换单元且对所述发光单元发出的光的亮度改变率为ra，所述第二子像素的波长转换单元为第二波长转换单元且对所述发光单元发出的光的亮度改变率为rb，所述第一子像素和第二子像素的波长转换单元由所述波长转换层中的第二像素限定层隔开，
在从所述第一子像素到第二子像素的方向上，相对于所述第二子像素的发光单元的顶面与所述第一子像素和第二子像素的发光单元之间的第一像素限定层的边界在所述衬底基板上的正投影，所述第二波长转换单元的底面与所述第一子像素和第二子像素的波长转换单元之间的第二像素限定层的边界在所述衬底基板上的正投影的位移为d4 2，
其中，
从所述发光单元顶面入射到所述透明间隔层并且可达到所述透明间隔层的顶面的光中，出射角在α 1以上的光的强度占比为x1％以下，其中，x1％＝p1×(ra/rb)，其中，p1≤5％，
其中，从所述透明间隔层的底面出发的光当出射角为α 1时，穿过所述透明间隔层的光路在所述衬底基板上的投影的长度小于等于d2+d4 2。
本公开的显示面板在面板厚度方向上至少包括在衬底基板上的三层结构，即发光层、透明间隔层和波长转换层。发光层负责发光。透明间隔层用于隔开发光层和波长转换层，可以对两者有封装或承载的作用。透明间隔层是至少在可见光范围内透明的材料层。这样，从发光单元发出的光可以经过透明间隔层后到达波长转换单元。波长转换层用于将由发光层发出并经过透明间隔层的光的波长转换为所需波长，以实现彩色显示。衬底基板用于承载上述三层结构。此外，与常规显示面板一样，为了实现显示，本公开的显示面板也包括阵列排布的子像素。图2示出了显示面板的相关膜层的局部示意图。
如图2所示，显示面板在XY平面内延展，并且以Z方向为厚度方向。Z方向为从显示面板背面到正面的方向。在Z方向上，依次有衬底基板4，发光层3，透明间隔层2和波长转换层1。在本公开中，如无特别说明，以显示面板的出光侧为“顶侧”或“正面”，其相反侧为“底侧”或“背面”，以便于描述相对方向。相应地，与底侧到顶侧的方向垂直的方向为“横向”。应当理解，这些方向都是相对而非绝对方向。
从显示面板正面看，其包含阵列排布的子像素。子像素通常为矩形阵列排布，但也可以是其他合适的阵列排布方式，只要与本公开的原则不冲突即可。图2示出了6×3个矩形阵列排布的子像素。若以X方向为行方向，Y方向为列方向，图中的子像素排列成3行6列的阵列。它们形成了排列成3行2列的6个像素，每个像素包含在行方向上排列的3个子像素。本公开对不同颜色的子像素排布形式不做要求，例如，排布形式可以为同一像素中3个子像素颜色不同，而同一列内的子像素颜色相同，当然也可以为其他形式。子像素为矩形，长边在Y方向上，短边在X方向上。图中的子像素均绘制为相同尺寸的。应当理解，子像素的颜色分布、形状和大小等都可以进行适当选择，只要与本公开的原则不冲突即可。图2中的虚线框标出了其中一个子像素的大致范围。
阵列排布的子像素包含相邻的第一子像素和第二子像素。在所述第一子像素和第二子像素中每一个中，包含一个在所述发光层中的发光单元和一个在所述波长转换层中的波长转换单元，所述发光单元与所述波长转换单元是层叠的并且由所述透明间隔层隔开。层叠的是指它们在显示面板的 厚度方向即Z方向上重叠。换言之，所述第一子像素和第二子像素中每一个包含一个在所述发光层中的发光单元和一个在所述波长转换层中的波长转换单元，波长转换单元以其底面接收其下方由发光单元顶部的顶面向上发出的光，并将光波长转换后从波长转换单元顶部射出，以完成显示。
图3示出了图2的虚线框中的子像素在X-Z平面内A-A’位置的示意性截面图。该子像素包含层叠的在发光层3中的发光单元31和在波长转换层1中的波长转换单元11，两者由透明间隔层2隔开。发光单元31与透明间隔层2的界面即其顶表面，向透明间隔层发光。波长转换单元11与透明间隔层2的界面即其底表面，接收来自透明间隔层的光照，并且光经过波长转换后从其顶面射出。波长转换单元11与发光单元31在竖直方向上彼此相对，或者说波长转换单元的底面与发光单元的顶面在衬底基板上的正投影是重叠的，从而绝大部分从发光单元31的顶面射出的光经过透明间隔层后到达波长转换单元11的下表面并进入波长转换单元11中。波长转换单元中的波长转换粒子将入射光的波长转换，并且从其顶表面射出。
如上所述，发光层是起到发光的作用的层，其中发出的光经过其上方的波长转换层，可以转换为其他颜色，并且也可以任选地不转换颜色，从而实现彩色显示。
本公开的显示面板的光发射由发光层中的发光单元实现。典型地，发光单元布置为阵列。发光单元典型地可以采用OLED发光，不过也可以为其他发光模式，如使用无机量子点发光材料的QLED或者Mini-LED或Micro-LED等。在发光层中，平行于显示面板的显示面阵列排布多个这样的发光单元，从而组成发光点阵。本公开的显示面板的每个子像素具有独立的发光单元，可以配合例如阵列基板以实现每个子像素背光的单独点亮和熄灭。在本公开的一个实施方案中，不同颜色子像素的发光单元是相同的。
在所述发光层中包括限定所述发光单元阵列的第一像素限定层。应当理解，在本公开中所称的“第一像素限定层”实际上限定的是各个子像素的范围，例如红、绿、蓝子像素的范围，而不是一个彩色RGB像素的总范围。
图案化的第一像素限定层设置在发光层中，围成了阵列排布的多个用于设置发光单元的空间。图3中，发光单元31的两侧由第一像素限定层32限定。
尽管图3中示意的第一像素限定层和发光单元均为矩形且具有竖直的侧壁，但它们也可以具有倾斜的侧壁。例如，第一像素限定层可以是正梯形，相应地形成倒梯形的发光单元。正梯形的第一像素限定层可以提供较大的出光面，并且第一像素限定层的侧壁上还可以设置反射层，从而提高发光单元的出光量。本公开关注第一像素限定层顶部及发光单元顶面处的几何特征，因此，对第一像素限定层和发光单元的形状不作特别的限制。
本公开的显示面板是包含波长转换元件的显示面板。波长转换元件用于将发光单元发出的光进行波长转换，变为其他颜色的光。应注意，在本公开中，波长转换与波长选择性透过不同。波长转换是指在无需额外使用能量的情况下将入射光的波长转换为另一种波长，而波长选择性透过是指仅允许入射光中一部分波长的光透过并阻止其他波长的光透过。波长转换可以是下转换，也可以是上转换。下转换与上转换相反，是指将波长较短的光转换为波长较长的光。通过使用不同的波长转换单元改变光的颜色，可以实现仅使用一种颜色的发光单元来实现彩色显示。
在波长转换层中具有波长转换单元，其用于将子像素中的发光单元发出的波长转换为所需颜色。例如，红色波长转换单元可以将蓝色背光转换为红色光，绿色波长转换单元可以将蓝色背光转换为绿色光。波长转换单元的实例可以是一个量子点(quantum dot，QD)材料部、无机荧光粉材料部或有机荧光材料部，其包括透明基质材料和分散在基质材料中的量子点、无机荧光粉或有机荧光材料。波长转换单元也可以由其他波长转换材料制成。基质材料可以是透明有机材料如树脂，例如固化的光刻胶树脂，或者固化的墨水。下转换材料可以采用任何合适的下转换材料，本公开对此没有特别的限定。其中，QD下转换材料由于可以通过粒径控制下转换性能而是特别优选的。
在一个实施方案中，波长转换单元可以包括基础树脂和与基础树脂混合(或分散在基础树脂中)的量子点。基础树脂可以是其中分散有量子点的介质。基础树脂可以由通常称为粘合剂的各种树脂复合材料中的至少一种 形成。然而，本发明构思不限于此。例如，能够分散量子点的介质可以用作基础树脂，而不管其名称、附加功能和/或组成材料如何。在一些示例性实施方式中，基础树脂可以是聚合物树脂。例如，基础树脂可以是丙烯酸基树脂、氨基甲酸乙酯基树脂、硅基树脂或环氧基树脂。基础树脂可以是透明树脂。
量子点可以是配置成转换入射光的波长的颗粒。量子点中的每个可以是具有拥有几纳米大小的晶体结构的材料，并且可以由数百到数千个原子组成。量子点可以表现出量子限制效应，其中由于小尺寸而增加了能带隙。当与大于能带隙的能量对应的波长的光入射到量子点时，量子点可以通过吸收光来激发，并且然后可以转变到基态同时发射特定波长的光。发射光的能量可以与能带隙对应。量子点的通过量子限制效应而引起的发光特性可以通过调节量子点的尺寸和/或组成来调节。
量子点可以由II-VI族化合物、III-V族化合物、IV-VI族化合物、IV族元素、IV族化合物或其任何组合形成。
II-VI族化合物可以选自由以下构成的组：选自由CdSe、CdTe、ZnS、ZnSe、ZnTe、ZnO、HgS、HgSe、HgTe、MgSe、MgS及其任何混合物构成的组的二元化合物；选自由AgInS、CdSeS、CdSeTe、CdSTe、ZnSeS、ZnSeTe、ZnSTe、HgSeS、HgSeTe、HgSTe、CdZnS、CdZnSe、CdZnTe、CdHgS、CdHgSe、CdHgTe、HgZnS、HgZnSe、HgZnTe、MgZnSe、MgZnS及其任何混合物构成的组的三元化合物；以及选自由HgZnTeS、CdZnSeS、CdZnSeTe、CdZnSTe、CdHgSeS、CdHgSeTe、CdHgSTe、HgZnSeS、HgZnSeTe、HgZnSTe及其任何混合物构成的组的四元化合物。
III-V族化合物可以选自由以下构成的组：选自由GaN、GaP、GaAs、GaSb、AlN、AlP、AlAs、AlSb、InN、InP、InAs、InSb及其任何混合物构成的组的二元化合物；选自由GaNP、GaNAs、GaNSb、GaPAs、GaPSb、AlNP、AlNAs、AlNSb、AlPAs、AlPSb、InNP、InNAs、InNSb、InPAs、InPSb及其任何混合物构成的组的三元化合物；以及选自由GaAlNP、GaAlNAs、GaAlNSb、GaAlPAs、GaAlPSb、GaInNP、GaInNAs、GaInNSb、GaInPAs、GaInPSb、InAlNP、InAlNAs、InAlNSb、InAlPAs、InAlPSb及其任何混合物构成的组的四元化合物。IV-VI族化合物可以选自由以下构 成的组：选自由SnS、SnSe、SnTe、PbS、PbSe、PbTe及其任何混合物构成的组的二元化合物；选自由SnSeS、SnSeTe、SnSTe、PbSeS、PbSeTe、PbSTe、SnPbS、SnPbSe、SnPbTe及其任何混合物构成的组的三元化合物；以及选自由SnPbSSe、SnPbSeTe、SnPbSTe及其任何混合物构成的组的四元化合物。IV族元素可以选自由Si、Ge及其混合物构成的组。IV族化合物可以是选自由SiC、SiGe及其混合物构成的组的二元化合物。
在这些情况下，二元化合物、三元化合物或四元化合物可以以基本上均匀的浓度存在于量子点中。替代地，量子点的一部分中的二元化合物、三元化合物或四元化合物的浓度可以不同于量子点的另一部分中的二元化合物、三元化合物或四元化合物的浓度。
量子点中的每个可以具有包括核和包围核的壳的核-壳结构。替代地，量子点可以具有一个量子点包围另一量子点的核/壳结构。核和壳的界面可以具有浓度梯度，其中存在于壳中的元素的浓度朝向中心逐渐变小。
量子点可以是纳米尺寸的颗粒。量子点中的每个可以具有约45nm或更小、具体地约40nm或更小以及更具体地约30nm或更小的发射波长光谱的半高全宽(FWHM)，并且可以在该范围内改善颜色纯度和/或颜色再现性。此外，通过量子点发射的光可以在所有方向上发射，并且因此，可以改善或实现宽视角。
此外，量子点中的每个的形状可以是本领域中已知的一般形状，但是量子点中的每个的形状不限于特定形状。例如，量子点中的每个可以具有球形形状、金字塔形状、多臂形状、立方纳米颗粒形状、纳米管形状、纳米线形状、纳米纤维形状或纳米板颗粒形状。可以根据量子点的颗粒尺寸来控制从量子点发射的光的颜色，并且因此，量子点可以发射各种发射颜色的光中的一种，诸如红色、绿色或蓝色，特别是红色或绿色。
在本申请中，以下若无特别说明，均以QD作为波长转换材料的示例进行说明。
波长转换层中的波长转换单元包括第一波长转换单元，其可以将入射的光转换为第一颜色光。例如，第一颜色可以为红色，即波长转换单元中存在红色波长转换单元。应当理解，第一颜色、第二颜色等用语仅是为了区分颜色，而非对颜色进行任何排序。为了实现彩色显示，波长转换层中 的波长转换单元还可以包括第二波长转换单元、或更多其他波长转换单元。例如，可以选择红色为第一颜色，绿色为第二颜色。又例如，可以以红色为第一颜色，绿色为第二颜色，蓝色为第三颜色。
可选地，除了波长转换单元之外，波长转换层还可以包括透明色阻单元。透明色阻单元对入射光是透明的，且不发生波长转换。这样，例如，蓝色子像素中的蓝色OLED发光可以穿过波长转换层但不经历波长转换，直接用于蓝色显示。优选地，透明色阻单元可以是光扩散单元，例如包含散射粒子，使得入射光在波长基本不发生改变的情况下发生散射，利于均匀显示。光扩散单元可以由具有光扩散能力的光扩散树脂制备，从而使蓝光穿过它之后更加均匀。
在一个实施方案中，本公开的显示面板可以为下转换型OLED显示面板。下转换型OLED显示面板使用一种颜色的短波长的OLED作为发光单元，典型地使用蓝光OLED。在不同颜色的子像素中，利用不同的下转换材料(如QD)对上述短波长的光进行下转换，变为波长相对较长的光，从而基于同一颜色的发光单元实现彩色显示。作为一个实例，对于所有颜色的子像素，都使用短波长的蓝色OLED发光。在红色子像素中，下转换材料将蓝色OLED发出的蓝光转换为红光。在绿色子像素中，下转换材料将蓝色OLED发出的蓝光转换为绿光。此外，由于蓝色本身为RGB显示的子像素颜色之一，因此在蓝色子像素中，可以不对蓝光进行下转换，直接用于蓝色子像素显示。当然，也可以使用蓝色转换材料调节蓝色像素的颜色。由此，实现红绿蓝(RGB)彩色显示。在本公开以下的讨论中，有时以蓝色背光作为短波长背光以及向绿色、红色光的下转换为例进行说明。但是，应当理解，根据需要，也可以选择其他颜色的发光或其他颜色的转换光。
图案化的第二像素限定层设置在波长转化层中，围成了阵列排布的多个用于设置波长转化单元的空间。图3中，波长转化单元11的底面的两侧由第二像素限定层12的底部限定。图3中示意的第二像素限定层和波长转换单元均为矩形且具有竖直的侧壁。不过，它们也可以具有倾斜的侧壁。第二像素限定层也用于围成设置透明色阻单元的空间。关于第二像素限定层的具体形状将在下文进一步阐述。
图4示出了图2中一个包含三个并排子像素的像素中在X-Z平面内A-A’位置的截面图。第一像素限定层32限定了三个发光单元31a、31b和31c，第二像素限定层12则限定了三个单元11a、11b和11c。作为示例，11a和11b为波长转换单元，11c为透明色阻单元。
图中示出了相邻的子像素。如前所述，本公开的子像素既可以是包含波长转换单元的子像素，也可以是包含透明色阻单元的子像素。不过，本公开的子像素中至少有两种相邻的子像素均包含波长转换单元且颜色不同，才能实现至少三种颜色的显示。第三种颜色可以是发光单元发的光经过另一种颜色的波长转换得到的，也可以是发光单元发的光经过透明色阻单元得到的。因此，本公开中任选均具有波长转换单元的两个相邻子像素作为第一和第二子像素，它们的顺序也可以对调。
在本公开中，发光层包括第一像素限定层和发光单元，波长转换层包括第二像素限定层和波长转换单元，透明间隔层在发光层和波长转换层之间。透明间隔层的底面即为发光层中的发光单元的顶面，且透明间隔层的顶面即为波长转换单元中的波长转换单元(或透明色阻单元)的底面。如图4所示，其中，发光层3中第一像素限定层32的顶面和发光单元31的顶面在同一平面内，并且该平面即为透明间隔层2的底面。波长转换层1中第二像素限定层12的底面和波长转换单元/透明色阻单元11的底面在同一平面内，并且该平面即为透明间隔层2的顶面。
应注意，上述各个层之间的界面关系是根据它们几何上的划分得到的。换言之，考虑到实际结构与理想几何形状或标准几何形状的偏差，上述的各个层的界面不一定是材料的实际界面。
例如，透明间隔层的顶面和底面不一定是不同材料的实际分层界面，也可以是同种材料中设定的划分面。又例如，第一像素限定层的顶部可以有一部分实际上处于透明间隔层的几何范围内。
本公开中，对于实际的膜层结构，根据第一像素限定层的顶面的形状来确定透明间隔层底面即发光层顶面的基准，并且根据第二像素限定层的底面的形状来确定透明间隔层顶面即波长转换层底面的基准。
以第一像素限定层为例，理想地，第一像素限定层的顶面为平面。这时，可以以其顶面作为发光层顶面的基准面。其正上方为透明间隔层。在 其两侧，低于该基准面的部分划分至发光单元，高于该基准面的部分划分至透明间隔层。
不过，这种理想的划分情况可能在实际器件中是难以得到的。例如，第一像素限定层顶部可以是非平面，且中央稍微凸起。此时，第一像素限定层不具有平的顶面。但是，仍需划分第一像素限定层与透明间隔层之间的平面界面。
由于像素限定层对于相邻子像素之间的漏光起到阻挡作用，因此，当考虑与漏光相关的串色时，在第一像素限定层的边界上考虑这样的点：其既可以从发光单元的发光材料层得到足够的光照，又可以向相邻的波长转换单元提供相应的光照。本公开中，选取第一像素限定层廓线上斜率变化率最大处的拐点作为上述点。在第一像素限定层两侧选取这样的点后，将它们的平均高度作为划分透明间隔层与发光层的基准。由于该基准取决于第一像素限定层的廓线，因此，其与材料的实际边界无关。在高于该基准的空间中，可以实际上存在一些第一像素限定层的材料(例如上述的微微凸起的部分)。低于第一像素限定层两侧的低于该基准的空间中，也可以实际存在一些与透明间隔层材料相同的材料。根据该基准划分后，将实际的膜层结构拟合为具有标准平直界面的膜层，并进一步计算和设计。具体地，一该基准线上第一像素限定层所占据的宽度作为相邻的发光单元的顶面之间的宽度d2。
以下给出一些划分的具体实例来进行说明。
发光单元中典型地具有阳极、发光材料层和阴极，并且通常阴极为公用阴极，覆盖发光材料层和第一像素限定层的顶部。例如，图5(a)示出了典型的结构。其中，311为阳极、313为发光材料层，且315为公用阴极。在这种情况下，以第一像素限定层的顶面作为划分发光层和透明间隔层的基准。因为在顶面的端点处的发光情况最代表本公开的原理。如图所示，以梯形左上角A1和右上角A2的连线及其延长线为基准划分发光层3和透明间隔层2。这时，第一像素限定层上方的公用阴极也属于透明间隔层的范围。
例如，图5(b)显示了另一种典型状况，其中公用电极315与其下方的表面是仿形的且上表面是凹凸的。不过，这并不影响透明间隔层与发光层 的划分。仍以第一像素限定层的顶面的两个端点作为划分基准。
如上所述，如图5(a)或5(b)所示的是比较理想的标准形状，第一像素限定层与发光单元具有共同的平面顶表面，并且以该共同平面顶表面作为发光层与透明间隔层的界面。这时，其中的各部分的平直分界都是清楚的。但是，实际的装置中，各个界面可能不是理想的平面。此时，取其中具有代表性的位点来确定几何参数。
显示面板的真实结构中的界面可能存在一些变形。不过，可以将它们归结为标准形状。
例如，图5(c)示出了一种比图5(a)更复杂的像素限定层周边的结构。其中，第一像素限定层32的顶面略微凸起，不再是理想的平面。在这种情况下，如图所示，选取第一像素电极层上切线斜率变化率最大的位置作为发光单元的顶表面位置和透明间隔层的底表面位置。切线斜率变化率最大的位置是第一像素电极层的基本竖直的侧壁向基本水平的顶面过渡的拐点位置。在该位置，既可以充分获得来自发光材料层313的光，又存在足够的向侧方射出且不被第一像素限定层32阻挡的光。实际上，在标准的梯形第一像素限定层的情况下，顶面的端点处便是切线斜率变化率最大的位置。
例如，图5(d)示出了还更复杂的结构。第一像素限定层32本身形成上大下小的“蘑菇形”。此时，选择在第一像素限定层的最宽处(虚线位置)上方的切线斜率变化率最大的拐点位置作为发光单元的顶表面位置和透明间隔层的底表面位置。这是因为，在最宽处以下的部分，第一像素限定层侧壁上的点的发光不能到达相邻的子像素，因此无需将它们考虑在内。应理解的是，本公开所考虑的是第一像素限定层顶面附近的光出射和第二像素限定层底面附近的光入射，因此，第一像素限定层或第二像素限定层的其他部分的几何形状不是本公开关注的重点。例如，第一像素限定层的截面可以是顶部窄、底部宽的正梯形，顶部和底部几乎同宽的矩形，或顶部宽、底部窄的倒梯形。这对确定发光单元之间的距离d2没有大的影响。
相应地，在图5(d)中根据拐点位置确定发光层3与透明间隔层2的分层界面。
应当理解，图5(c)和(d)的切线所针对的是整体廓线，忽略壁上的微小 凹凸结构。
以上仅是对真实结构进行标准化区域划分的一些实例。可以基于本公开的原理对真实结构进行正确的划分，并且符合本公开限定的真实结构都在本公开的保护范围之内。
如上所述，阴极在第一像素限定层顶部的厚度与其在发光材料层顶部的厚度不同时，可以将其高于第一像素限定层顶面的部分作为透明间隔层的一部分，而将其在第一像素限定层之间低于第一像素限定层顶面的部分作为发光单元的一部分。
例如，图5(e)示出了在一个实施方案中当公共阴极下表面非平面时的层结构划分。第一像素限定层32限定了发光层3的高度，且其上覆盖的公共阴极315的一部分在第一像素限定层32的顶面以下。在此情况下，可以将公共阴极315在第一像素限定层上方的部分作为透明间隔层2的一部分，而在第一像素限定层32之间的部分作为发光单元31的一部分。透明间隔层2与发光层3之间的边界用下方的虚线表示。
除了公共阴极之外，其他具有在第一像素限定层顶部高度之上部分的膜层也都可以如此划分。
在垂直纸面的方向上，第一像素限定层与发光单元的边界也可以不是直线。在此情况下，以直的平均线代表其边界。
总之，原则上，以第一像素限定层的平面顶面位置作为确定发光层与透明间隔层的基准。当第一像素限定层与两侧的发光单元的顶面的边界点有轻微高度落差时，可以以这些边界点的平均高度获得标准平面顶面的高度。当第一像素限定层的顶面相对于两侧的发光单元的顶面稍微隆起时，可以以像素限定层顶部的切线斜率拐点位置来作为发光单元顶面的边界点。
类似地，也可以对波长转换层进行标准化的几何划分。
例如，如图5(e)所示，特别是在使用对盒方法将波长转换层1与发光单元3组装的情况下，波长转换层1中可以有覆盖波长转换材料111的覆盖层或封装层113。在覆盖层113与公共阴极315之间，可以是透明封装层21。类似地，以第二像素限定层的底面为基准划分波长转换层与透明间隔层之间的界面。，覆盖层113的一部分归入波长转换单元11，另一部分 归入透明间隔层2。透明间隔层2与波长转换层1之间的边界用上方的虚线表示。
例如，图5(f)示出了当第二像素限定层的底面不是平面时，类似地确定拐点，进而划分波长转换层与透明间隔层之间的界面。其中，12为第二像素限定层。其两侧具有子像素a和b，各自具有波长转换单元111a和111b，并且第二像素限定层12和波长转换单元111a和111b均被封装层113覆盖。根据第二像素限定层12底面的廓线形状确定拐点B1和B2，并且以它们的平均高度作为基准，划分波长转换层1和透明间隔层2的边界。封装层113的一部分属于透明间隔层。
本公开提供了子像素之间区域的特殊尺寸设计以至少部分解决串色问题。
图6示意性地示出了本公开的原理。图6(a)为原理示意图，显示了由第一像素限定层32和第二像素限定层12左侧的子像素a和右侧的子像素b的局部。左侧子像素a包括层叠的发光单元31a和波长转换单元11a，右侧子像素b包括层叠的发光单元31b和波长转换单元11b。理想地，第一像素限定层32的顶面和发光单元31a、31b的顶面在同一平面内，第二像素限定层12的底面和波长转换单元的底面11a、11b也在同一平面内。发光单元的顶面是例如其OLED的透明像素电极如透明阴极的顶表面。间隔层是单一材质。此时，从31a与32的边界点A1射出的光中，向区域I(线段A1至B2右侧区域)射出的光可以到达相邻子像素的11b，向区域II(线段A1至B1左侧区域)射出的光可以到达本子像素的11a，而向区域III(线段A1至B2左侧和线段A1至B1右侧区域)射出的光将被12遮挡。到达11b的光将会引起11b的发光，可能造成串色。
本公开的构思是，尽管不可避免地有射向区域I并到达11b的光，但是，只要由此引发的子像素b的发光亮度与发光的子像素a亮度相比足够小，观看者将无法发现子像素b的发光，不会导致实质上的串色。换言之，本公开的目的是控制子像素b的相对发光亮度而非单纯阻挡相邻子像素之间的漏光。
对于显示面板的使用者即观看者而言，子像素的相对亮度是其能否注意到产生了颜色差别的主要因素。亮度(luminance)的定义是单位投影面 积上的发光强度(luminous intensity)，单位是尼特(nit)，即坎德拉/平方米(cd/m 2)。发光强度为单位立体角内的光通量(luminous flux)。光通量是指人眼所能感觉到的辐射功率，单位为流明(lm)。特定波长的光通量与辐射功率和该波长的相对视见率(vision rate)的乘积成正比。相对视见率也称为光谱光视效率函数或者人眼视见函数。标准光谱光视效率函数可以由例如国际照明委员会(CIE)得到。
从波长转换单元的正面观察到的发光亮度与为波长转换单元提供背光的光源的初始功率、波长转换导致的波长变化、以及波长转换单元本身对入射光的转换能力都是有关的。本公开中，将波长转换单元(或透明色阻单元)对于亮度的改变能力归纳为“亮度改变率”这一参数。在波长转换单元中，亮度改变率用于表示在入射光由于受到波长转换单元作用得到波长转换后的出射光这一过程中所产生的亮度改变。具体地，亮度改变率是从波长转换单元出射的波长转换后的光的亮度与入射到波长转换单元的光的亮度的比值。应当注意，可能存在一部分入射光由于没有遇到波长转换粒子而未经过波长转换并直接透过波长转换单元射出，但因为在显示装置中还设置有用于滤除多余背光的彩膜，所以经过波长转换单元后剩余的入射光亮度基本不会对最终的显示亮度造成影响，不会对串色造成影响。所以，在本公开中考虑亮度变化率时，只计算波长转换后的光的亮度。亮度改变率受到光波长变化和波长转换能力的综合影响。光波长变化可以影响其亮度中相对视见率的部分，而波长转换能力可以影响其光子数的变化。在量子点波长转换单元中，波长转换能力受其量子效率的影响。在透明色阻单元中，亮度改变率表示从透明色阻单元出射的光的亮度与入射到透明色阻单元的光的亮度的比值。因为其中波长没有改变，所以其亮度的改变基本仅受到光子数变化的影响。具体的波长转换单元或透明色阻单元针对特定入射光波长的亮度改变率可以通过试验测得，或者可以根据材料性能计算得到。
例如，可以使用已知亮度的准直背光照射波长转换单元结构的底面，并且在波长转换单元的顶面测量波长转换光的亮度，来得到亮度改变率。测试的波长转换单元可以是预制的模拟样品，从而可以根据测试结果进行尺寸设计。
由发光单元31a引起的子像素b的波长转换单元11b的发光亮度与子像素a的11a的发光亮度之比(或相对亮度)越小，串色表现越弱。在本公开中，将相邻子像素(例如像素b)的波长转换单元的发光亮度与提供发光的子像素(例如像素a)的波长转换单元的发光亮度之比用参数p表示。
发明人通过仿真模拟发现，对于不同的颜色组合，存在不同的临界p值，并且在该临界值p以下时，可以完全确保人眼感受不到串色。在一些实施方案中，规定该临界p值小于5％。更优选地，规定该临界p值小于3.1％。最优选地，该临界p值小于2％。在小于2％时，对任何颜色组合，都可以确保没有观察得到的串色。
本公开通过设计子像素之间的几何结构来确保上述p值在所需的临界值以下。在图6(a)中，A1的发光所造成的11b的发光(波长转换发光)由发射到I区中的光引起，而所造成的11a的发光由发射到II区中的光引起。
注意到，波长转换发光由于改变了波长，因此对光的亮度有影响。当11a和11b中转换的波长不同时，即使受到同样强度的光照射，显示的亮度也不同。
本公开中，采用参数r来表征波长转换材料对入射光的亮度的改变比例。即，当入射光的亮度为B时，出射光的亮度为B×r。称第一子像素a的亮度改变率为ra，第二子像素的亮度改变率为rb。ra和rb是与材料性质有关的参数。应当注意，由于波长发生改变，亮度改变率可以是大于100％的数值。
由此，若射入11b的光的总的亮度为B I，则造成的出射光总亮度为BI×rb，入射11a的光的总的亮度为D II，则造成的出射光总亮度为D II×ra。因此，11b的发光与11a的发光的相对亮度为(D I×rb)/(D II×ra)＝D I/D II×(rb/ra)。
对于同样的由31a射出的光来说，其亮度与其强度成比例。因此，由A1的发光造成的11b与11a的相对亮度将是(射到11b的光的总强度/射到11a的光的总强度)×(rb/ra)。
如上所述，ra和rb是与材料相关的参数，而射到11b的光的总强度和射到11a的光的总强度则是与几何结构有关的参数。
在图6(a)所示的平面中，从A1点射到11b的光的总强度近似地是出射角为γ的光线的总强度。严格地说，从发光单元出射的光由于在到达波长转换层之前要穿过透明间隔层，因此强度会发生一定的衰减。不过，一方面透明间隔层对发光单元的发光的透过性好，总的衰减程度不大；另一方面，衰减发生在各个角度，对于相邻像素的相对亮度变化影响不大。因此，忽略透明间隔层中因材料透射率导致的衰减。角度γ的左边界的出射光将达到11b左边界点B2，右边界的出射光将达到11b的右边界点C2。尽管图6(a)中的角度γ看上去较小，但是实际上11b的宽度比图中所示宽得多，因此，角度γ在区域I中占据的角度比例并不小。此外，A1出射的光的强度在整个出射角范围内分布是不平均的，并且当出射角很大时，其强度相对小得多(将在下文详述)。因此，超出γ角度的光的强度在此可以忽略不计。这样，可以近似地认为A1向右侧发射的光中，出射角在α以上的光的总强度射到11b，而出射角小于α的光都射入区域III中，并且被第二像素限定层12所阻挡。
而A1向左侧发出的光中，在θ范围内的光可以达到11a。如上所述，超出C1左侧的光虽然不对11a的发光作出贡献，但角度很大且总强度很小，也可以忽略不计。此外，虽然B1右侧对应的小角度中的发光未对11a的发光作出贡献，但有大量A1左侧的发光可以到达11a并对发光形成一定的补偿，因此，可以近似地认为，从A1入射到11a的总强度大致是从A1发出的光向θ范围以及其左侧的全部发光的总强度，入射到11b的光的总强度是右侧的0-90°范围内出射角大于α的光的总强度，而入射到11a的光的总强度是左侧的-90-0°范围内全部出射角的光的总强度。
这时，从A1入射到11b与11a的光相对亮度即为(出射角大于α的光线的总强度/全部光线的总强度)×(rb/ra)。如上所述，相对亮度应不高于p1的临界值，例如5％，优选3.1％，更优选2％，以尽量降低串色现象。当p1小于2％时，基本上可以完全避免串色现象。此时，(出射角大于α的光线的总强度/全部光线的总强度)×(rb/ra)＝p1。此处，当计算比例时，可以将左右侧的全部发光计算在内，即从-90°至+90°范围内的全部发光。这与仅计算0-90°的单侧发光所得的结果是相同的。
上式中，一定角度范围内的光线总强度可以根据A1点的发光强度与 角度的关系曲线计算。通过发光强度-角度曲线中按角度积分，即可获得总强度。
由此，在确定p、ra、rb后，从上述等式计算出α的临界值。进一步，根据该临界值，可以设计12、32以及透明间隔层之间的几何结构。当B2足够靠右时(超过临界位置后)，A1发光中出射角为α的光线不能全部到达11b，并且因此，到达11b的光线的总强度在经过11b转化波长后，产生的亮度与到达11a的光线波长转换后产生的亮度之比(即相对亮度)必将小于临界值p1，从而解决了串色问题。
例如，在一个实施方案图6(a)所示的实施方案中，取p的临界值p1为5％。则(出射角大于α的光线的总强度/全部光线的总强度)×(rb/ra)＝5％。按照此α值求得临界的B2位置。则当子像素设计为12的右端比B2更靠右时，均可以解决串色问题。
更具体地，例如，透明间隔层为折射率均匀的单层材料时，rb/ra＝2时，出射角大于α的光线的强度占比为2.5％。此时，对应的α角度例如为80°。由于透明间隔层为单层材料并且光在其中直线传播，因此，若透明间隔层厚度为d1＝2微米，则B2到A1的临界横向距离为2微米×tan 80°＝11.34微米。上述横向距离是32顶面的宽度d2与12底面超出32边界部分d4 2之和。只要将d2+d4 2设计为大于此临界值，即可解决串色问题。例如，当32的宽度d2是10微米时，B2超出A2的部分d4 2为大于1.34微米即可。
应当理解，虽然图中仅示出了在纸平面内的光线，但由于从A1出发向纸面之外的光线是左右对称的，并且发光单元和波长转换单元也均在垂直于纸面的方向上延伸，即在垂直纸面的方向上也是对称的，因此，这些不在纸面内的光线对上述相对亮度的临界估算的影响可以抵消或忽略。
图6(a)中仅示出了对左侧子像素a向右侧子像素b串色的分析。右侧子像素向左侧子像素的串色也可以对称地分析。对于右侧向左侧子像素的串色，可以根据其颜色选择设定临界值p2。p2≤5％，更优选≤2％。可以使p2与p1相等，只要可以保证没有明显的串色即可。应当注意，本公开的各种参数的关系都可以适当地扩展至其他子像素的情况下，只要符合本公开的原理即可。
具体地，在从所述第二子像素到第一子像素的方向上，相对于所述第 一子像素的发光单元的顶面与所述第一子像素和第二子像素的发光单元之间的第一像素限定层的边界在所述衬底基板上的正投影，所述第一波长转换单元的底面与所述第一子像素和第二子像素的波长转换单元之间的第二像素限定层的边界在所述衬底基板上的正投影的位移为d4 1，
其中，
从所述发光单元顶面入射到所述透明间隔层并且可达到所述透明间隔层的顶面的光中，出射角在α 2以上的光的强度占比为x2％以下，其中，x2％＝p2×(rb/ra)，其中，p2≤5％，
其中，从所述透明间隔层的底面出发的光当出射角为α 2时，穿过所述透明间隔层的光路在所述衬底基板上的投影的长度小于等于d2+d4 1。
只要A1与B2或A2与B1的横向距离满足上述关系，便可以有效地避免串色。换言之，只要横向距离d2+d4 1或d2+d4 2满足大于相应的临界角α对应的光路投影长度的临界值，便可避免串色。可选地，不必将上述横向距离设置得过大，只需比临界值稍大即可。换言之，该横向距离与临界值的差可以尽量小。该横向距离与临界值的差可以小于等于10μm。可选地，从所述透明间隔层的底面出发的光当出射角为α 1时，穿过所述透明间隔层的光路在所述衬底基板上的投影的长度与d2+d4 2之差小于等于5μm、小于等于4μm、小于等于3μm、小于等于2μm、小于等于1μm，小于等于0.5μm、或d2+d4 2设计为恰好对应于临界出射角α 1的情况。可选地，当出射角为α 2时，穿过所述透明间隔层的光路在所述衬底基板上的投影的长度与d2+d4 1之差小于等于5μm、小于等于4μm、小于等于3μm、小于等于2μm、小于等于1μm，小于等于0.5μm、或d2+d4 1设计为恰好对应于临界出射角α 2的情况。
与相关技术相比，本公开的几何设计没有在相邻子像素之间增加遮光部件，给出相邻子像素的间距下限，从而可以在不发生串色的同时尽可能提高分辨率。
图6(b)示意性示出了一个比图6(a)的原理图结构更精细的实施方案中两个相邻子像素a和b之间的结构，其中透明间隔层具有多个层叠的亚层。第一子像素a包含发光单元31a、波长转换单元11a，第二子像素b包含发光单元31b、波长转换单元11b。第一子像素的发光单元的顶面与第一像 素限定层的边界为A1，波长转换单元的底面与所述第二像素限定层的边界为B1。第二子像素的发光单元的顶面与第一像素限定层的边界为A2，波长转换单元的底面与所述第二像素限定层的边界为B2。发光单元31a与31b各自包括阳极311和发光材料层313。两者之间由第一像素限定层32隔开，发光单元31a与31b之间的顶面之间的距离即为两者之间第一像素限定层顶表面处的宽度d2，即A1点与A2点之间的宽度。发光单元中包括阳极和发光材料层。在发光单元31a、31b和第一像素限定层之上是透明间隔层2。图6(b)所示的示意性透明间隔层具有4个膜层，包括公共阴极315，第一无机层211、有机层212和第二无机层213。波长转换单元11a和11b之间为第二像素限定层。波长转换单元11a和11b之间的底面之间的距离即为两者之间第二像素限定层底表面处的宽度d3，即B1点与B2点之间的宽度。在从所述第二子像素到第一子像素的方向上(即向左的方向上)，相对于所述第一子像素的发光单元的顶面与所述第一子像素和第二子像素的发光单元之间的第一像素限定层的边界A1在所述衬底基板上的正投影，所述第一波长转换单元的底面与所述第一子像素和第二子像素的波长转换单元之间的第二像素限定层的边界B2在所述衬底基板上的正投影的位移为d4 1。此处，d4 1可以为负值，即表示B1也可以在A1左侧。在从所述第一子像素到第二子像素的方向上(即向右的方向上)，相对于所述第二子像素的发光单元的顶面与所述第一子像素和第二子像素的发光单元之间的第一像素限定层的边界A2在所述衬底基板上的正投影，所述第二波长转换单元的底面与所述第一子像素和第二子像素的波长转换单元之间的第二像素限定层的边界B2在所述衬底基板上的正投影的位移为d4 2。d4 1和d4 2实际上也就是第二像素限定层的底部边缘相对于其下方的第一像素限定层的边缘突出或缩入的横向距离。d3＝d2+d4 1+d4 2。
本公开通过根据发光单元的不同发光角度的占比以及波长转换单元对发光单元的亮度改变率来确定相邻子像素之间第一像素限定层、第二像素限定层的尺寸，进而控制相邻子像素的串扰。
在图6(b)中，在子像素a的发光单元11a所发出的光中，可能对子像素b造成串扰问题的是那些可以从发光单元11a的发光面经过透明间隔层到达波长转换单元11b的那些光。本公开通过结构设计，将这样的光的量 控制在不会对子像素b的显示造成明显影响的程度。
波长转换层11b的底面中与发光单元31a的顶面中的A1点最近的点是其左端点B2，即第二像素限定层的底表面的右端，或者说波长转换单元的底面与所述第二像素限定层的边界。对于从A1点入射的光来说，出射角较小的光将会在X方向上传播得较近，不足以到达B2点；仅仅那些出射角较大的光才能够到达B2点。在本公开中，入射角和出射角均是指与法线的夹角，在0-90°的范围内，并且入射、出射是相对于界面而言。换言之，存在临界的出射角α 1，当出射角为临界角以下时，其发光g1不会到达波长转换单元11b造成串扰，而出射角等于和大于临界角的光g2、g3才有可能到达波长转换单元11b。图中虚线表示光线对应关系，但不表示光线实际沿直线传播。与图6(a)不同的是，光线在A1和B2之间不是直线前进，而是发生多次折射。图中以虚线示意这些折射，未示出具体折射光路。不过，尽管透明间隔层中发生折射，但本公开的原理仍然适用。
如上所述，与彩膜层不同，入射到波长转换层的光即使出射角大，也可能造成串色问题。根据发光单元的出光角度的强度分布来确定上述临界角。通过使得上述临界角满足“大于临界角的入射光量占比低于阈值”，可以将串色亮度控制得足够小，从而从实际上解决串色问题。
在本公开中，上述阈值通过第一子像素和第二子像素的波长转换单元的亮度改变率的相互关系确定。显示器件的子像素的显示效果与其发光强度及人眼对其发光波长的感知能力相关，综合表现为其亮度。参考图6(b)，当A1向右侧发出的到达透明间隔层顶面的光中有x1％可能到达右侧相邻的第二子像素时，第二子像素中可能由于串色而产生的亮度与发光单元的发光亮度之比为x1％×rb，而A1点向左侧发出的光造成的第一子像素本身的亮度与发光单元的发光亮度之比则为ra，其中ra和rb分别为第一子像素和第二子像素对发光单元的光的亮度转化率。在第二子像素中的串色发光与第一子像素正常发光相比较，亮度比为x1％×rb/ra，可以表示为x1％×(rb/ra)。经仿真模拟，当该亮度比低于5％时，基本上不发生可以被人眼察觉的串色现象。因此，当以p为临界值p1时，x1％×(rb/ra)＝p1，即x1％＝p1×(ra/rb)。临界值p1可以更优选为3.1％以下，还更优选为2％以下。
应当注意，与图6(a)的单一材料的透明间隔层的情况不同，图6(b)的透明间隔层中由于有不同折射率的膜层交叠，会发生全反射，造成一部分光无法到达波长转换单元。此时，在计算到达两个子像素的波长转换单元的光强度时，不包含不可能到达透明间隔层顶面的那些光，因为这些光不会造成串色。本公开的方案仅考虑从所述发光单元顶面入射到所述透明间隔层并且可达到所述透明间隔层的顶面的光中的光强占比。当透明间隔层中存在全反射的可能时，需除去全反射的部分。例如，当透明间隔层中存在折射率为1.8和在出光方向上与其紧邻的折射率为1.5的亚层时，折射率1.8的亚层向折射率为1.5的亚层入射的入射角大于约52°的光将被全反射。此时可以根据对应于该层中0至52°范围的最初入射光的总光强，计算相应的临界角度等。而入射角大于52°的光强度因为未达到透明间隔层的顶面，不会对波长转换层产生影响，因此在临界几何参数的计算中不予考虑。
因此，若将从A1点到达B2点的光的强度占比限制在上述临界值x1％以下，则可以有效地消除串色问题。此时，从所述透明间隔层与所述发光单元的界面处入射的出射角为α 1的光在其顶面出射时，入射点到出射点经过的横向距离需要小于等于d2+d4 2，即A1到A2的距离及A2到B2的横向距离之和。可以理解，若第二像素限定层边缘相对于第一像素限定层边缘缩进，d4 2也可以是负值。其中所述发光单元所发出的入射到所述界面的光中，出射角大于α 1的光的强度占比为x1％以下。
总之，本公开的设计思想为如下。第一，确定两个相邻子像素的波长转换单元(或透明色阻单元)对发光单元亮度的改变系数。第二，考虑从一个子像素的发光单元发出的光中，到达相邻子像素和到达本子像素的光的比例为多少时，会使得相邻子像素产生的足以显示串色的亮度。在此过程中，将上述亮度改变系数考虑在内，并且将足以显示串色的亮度比例设定为模拟得到的临界比p。最后算得到达相邻子像素的光的不应超越的占比上限x％。第三，考虑这些占比的光对应的在透明间隔层底面处的临界出射角α，规定出射角大于α的光量为上述上限x％。即，算出一个出射角度下限，并且需避免出射角度小于该下限的光也能到达相邻子像素。第四，根据该临界出射角，计算出光路起点和终点之间的横向距离d2+d4的 下限。这样，只要d2+d4的距离足够大(大于临界角α对应的光路的起点和终点之间的横向距离)，便可以保证出射角度小于α的光不会进入相邻子像素，进而可以保证仅有小于x％的光进入相邻子像素，进而可以保证在经过波长转换单元的亮度转换之后，相邻子像素中产生的亮度小于发光子像素中产生的亮度的临界比，从而不发生对实际观看造成影响的串色。
对于实际制备的非标准形状的第一像素限定层、第二像素限定层、发光单元、波长转换单元和透明间隔层，可以将它们根据上述原则拟合至标准图形后，检验其几何特征是否符合本公开，即是否可以达到本公开的使得有限比例的光达到相邻子像素，并且经过换算后是否满足相对亮度的限制。应理解，虽然后续附图均基于标准图形绘制，但其也包括符合上述原则的技术方案。
发光单元所发出的入射到所述界面的光中，大于特定值的光的强度比例所对应的临界出射角α的值可以通过试验测量或建模计算。发明人发现，从发光单元在其与透明间隔层的界面处进入透明间隔层的光强度可随着角度变化而变化。例如，出射角为0°(即法线方向)的光强度最高，而出射角在接近90°时强度则接近零，而且，强度与角度之间的关系可以不是单调增减的。图7示例性地示出了一种出射角-光强度曲线。强度在40度左右降至极小值后反而上升，并且在60度左右达到极大值后再度下降。上述阈值可以根据在出射角-光强度曲线中计算曲线下方的面积比例来计算。由此，可以从阈值确定临界角大小。出射角-光强度曲线可以试验测量，也可以建模计算。图7所示的光场分布在60°以上一些角度的光强占比如下表所示。
角度(°) 60 65 70 75 80 85
光强占比(％) 21.8 15.6 11.0 6.45 2.4 0.6
图7和上表所示仅为一种示例性光场分布。具体的光场分布可以与图7所示的不同。
通过上述结构设计，第一子像素对第二子像素的串色影响得到准确控制。
同样，图6(b)中的封装结构层、第一像素限定层、第二像素限定层尺寸也应保证第二子像素对第一子像素的串色影响受到控制。为此，出射角 为α 2光在其顶面出射时，出射点与入射点的横向距离不大于d2+d4 1，其中所述发光单元所发出的入射到所述界面的光中，出射角大于α 2的光的强度占比为x2％以下，其中x2％＝p2×(rb/ra)。其中，选择临界值p2，其为≤5％的值。
注意到，前述条件仅限定了d2与d4 2之和或d2与d4 1之和，而对d2在d2+d4 2中占多少比例没有要求。通常，先设计第一像素限定层的尺寸，再进一步设计第二像素限定层的尺寸。换言之，先确定d2后，再在d2的基础上确定d4 1及d4 2。在图6(b)所示的实施方案中，第二像素限定层底部比第一像素限定层顶部宽，并且因此d4 1及d4 2为正值。不过，在一些实施方案中，d4 1及d4 2也可以为负值，对应于第二像素限定层底部比第一像素限定层顶部窄的情况。在另一些实施方案中，d4 1及d4 2可以基本上为0。
在一些实施例中，为了便于制备，第二像素限定层与第一像素限定层中心对位设置，因此d4 1与d4 2相等。可以理解的是，当ra不等于rb时，d4 1与d4 2的取值的临界值应满足使出射角在α 1以上的光的强度占比为x1％以下，并且使出射角在α 2以上的光的强度占比为x2％以下。这时，可以取d4 1与d4 2的临界值中较大者同时用于两侧的子像素中，实现对称设计。例如，当ra＞rb时，第一子像素的波长转换材料的亮度改变率较高。此时，本应x1＞x2，即出射角α 1以上的光占比的上限可以大于出射角α 2以上的光占比的上限，即α 1＜α 2，相应地d4 1的临界值比d4 2的临界值大。此时，可以将d4 2也按照d4 1的临界值设置，使得光路横向传播距离值满足防止第二子像素向第一子像素串色的要求，同时该光路横向传播距离也自然满足防止第一子像素向第二子像素串色的要求。
当然，本公开也可以根据相邻两个子像素的具体参数来设计不同的子像素几何尺寸。如果不考虑第二像素限定层与第一像素限定层在截面中呈现轴对称形态，则d4 1和d4 2可以不等。
在一个实施方案中，第二像素限定层与第一像素限定层中心对位设置且其底部与第一像素限定层顶部宽度相等，即d4 1＝d4 2＝0。这比较方便用相同的掩模等装置进行膜层制备。
在一个实施方案中，考虑到实际生产中可能有1-5微米的对位精度偏差，因此，可选地，尺寸范围可以放宽至|d4 1|≤5μm、≤4μm、≤3μm、 ≤2μm、≤1μm。同样，可选地，|d4 2|≤5μm、≤4μm、≤3μm、≤2μm、≤1μm。
确定临界角大小后，即可通过在透明间隔层中的光路计算，确定各尺寸的相互关系。换言之，当按照所得的尺寸关系制备显示面板后，该显示面板将不会表现明显的串色问题。此时，结构设计简化为对透明间隔层中的独立光路计算。图8示出了示例性的透明间隔层中的示意性光路。其四个层由下至上分别为L1至L4。例如，其中L1可以为ITO阴极层，其上依次覆盖第一无机层、有机层、第二无机层等。它们的折射率分别为n1至n4。则从透明阴极底侧入射且出射角为θ 1的光线向着透明间隔层顶面前进过程中，每经过一个界面，便按照折射率公式改变一次角度。n1sinθ 1＝n2sinθ 2＝n3sinθ 3＝n4sinθ 4。根据各个角度，可进一步计算横向光程与纵向光程的关系。横向光程d＝L1tanθ 1+L2 tanθ 2+L3 tanθ 3+L4 tanθ 4。由此，通过将θ 1规定为由x1确定的α 1或由x2确定的α 2，即可计算出第一子像素与第二子像素之间的几何关系，由此完成结构设计。
由此，当使用特定的透明间隔层时，可以根据本公开的关系得到所需的子像素之间的横向间距。反之，当需要一定的分辨率时，则可根据根据本公开的关系选择透明间隔层及其具体亚层构成。
在一个实施方案中，所述透明间隔层的厚度为d1，所述透明间隔层包括由下到上堆叠的m个子层，第i个子层的厚度和折射率分别为L i和n i，i为1至m，
各参数满足：
Figure PCTCN2021096070-appb-000003
Figure PCTCN2021096070-appb-000004
其中i为1至m的整数，n isinθ 1i为常数且θ 11＝α 1。
换言之，光路的横向前进距离为在每个亚层中的前进距离之和。每个亚层中的前进距离与每个入光界面的出射角和亚层厚度相关。每个入光界面的出射角则与该亚层及前一亚层的折射率相关。当光线进入第一亚层的底侧界面时的出射角α确定时，即可根据上述方式计算d1、d2及d4。例 如，对于α 1的出射角，可以如上计算d2+d4 2；对于α 2的出射角，可以类似地计算d2+d4 1；对于下述α 3的出射角，可以类似地计算d5+d4 3；等等。
还需注意的是，当透明间隔层的底部中存在金属透明阴极时，极薄的金属透明阴极虽然对于光线是透明的，但光在其中的折射行为可能不适合用常规的折射率进行表征。不过，金属透明阴极的厚度相对于其上的无机/有机封装层小得多。典型地，金属透明阴极厚度通常最大在几十纳米，而其上的封装层的尺度为微米级。因此，在本公开上述公式的计算中，可以忽略金属透明阴极的存在。即不将金属透明阴极的厚度和光在其中的横向前进计算在内。此时，光出射角度θ 11、θ 12从金属透明阴极的顶面作为界面开始算起。不过，对于例如厚度较大的阴极如ITO电极，光线在其中的行进不应忽略。
在一个实施方案中，所述阵列排布的子像素还包含第三子像素，所述第一子像素与所述第三子像素相邻，在所述第三子像素中，包含一个在所述发光层中的发光单元和一个在所述波长转换层中的透明色阻单元，所述发光单元与所述透明色阻单元是层叠的并且由所述透明间隔层隔开，
所述第一子像素和第三子像素的发光单元由所述发光层中的第一像素限定层隔开，且顶面间距为d5，
所述透明色阻单元对所述发光单元发出的光不进行波长转换并且亮度改变率为rc，所述第一子像素的波长转换单元和所述第三子像素的透明色阻单元由所述波长转换层中的第二像素限定层隔开，
在从所述第三子像素到第一子像素的方向上，相对于所述第一子像素的发光单元的顶面与所述第一子像素和第三子像素的发光单元之间的第一像素限定层的边界在所述衬底基板上的正投影，所述第一波长转换单元的底面与所述第一子像素的波长转换单元和第三子像素的透明色阻单元之间的第二像素限定层的边界在所述衬底基板上的正投影的位移为d4 3，
其中，
从所述发光单元顶面入射到所述透明间隔层并且可达到所述透明间隔层的顶面的光中，出射角在α 3以上的光的强度占比为x3％以下，其中，x3％＝p3×(rc/ra)，其中，p3≤5％，
其中，从所述透明间隔层的底面出发的光当出射角为α 3时，穿过所 述透明间隔层的光路在所述衬底基板上的投影的长度小于等于d5+d4 3。
如上所述，本公开的波长转换层中也可以具有透明色阻单元。具有透明色阻单元的子像素用于使得发光单元的发光不经波长转换直接射出。对于一个具有波长转换单元的子像素和一个与之相邻的具有透明色阻单元的子像素来说，两者的相互串色情况如下。
图9示意性示出了本公开的一个实施方案中两个相邻子像素c和a之间的结构。第一子像素a包含发光单元31a、波长转换单元11a，第三子像素c包含发光单元31c、波长转换单元11c。图9中的透明间隔层、发光单元、第一像素限定层和第二像素限定层等部件类似于图6。
与图6(f)不同的是，从第一子像素的A3点到达B4点的光线进入的是透明色阻单元11c。透明色阻单元11c由于不具有波长转换粒子，因此即使其含有散射粒子，从第一子像素的A3点到达B4点的光线也不会明显地产生在显示面板正面的发光。换言之，从第一子像素到达无波长转换的第三子像素的串色水平可以忽略，不必通过特殊的几何参数对其进行限制。在这种情况下，也可以对距离d4 4不做具体限定。当然，也可以采取本发明的基于相对亮度的构思对d4 4进行限定。
不过，从第三子像素的A4点到达B3点的光线仍造成串色隐患，需要采用本公开的原理对其进行控制。此时透明色阻单元对发光单元的发光没有波长转换，但因材料的亮度改变率仍会使其亮度改变，其中亮度改变率为rc。rc是始终小于100％的值。相应地，当选定前述相对亮度临界值p选定，可以从p、ra、rc计算出从第三子像素的发光单元31c向第一子像素的波长转换单元11a的临界漏光强度比例对应的临界出射角α 3。防串色的相对亮度临界值的优选范围与上述相同。
通常，各个子像素之间的像素限定层顶面的宽度相等，因为通常发光单元都是相同大小和尺寸并且均匀分布的。换言之，可以将几何参数设计为d5＝d2。
根据前述方式，可以设计具有三种颜色子像素的显示面板中各个层的具体几何结构。
在一个实施方案中，发光单元发蓝光，第三子像素中包含透明色阻单元且为蓝色子像素，所述第一子像素为红色子像素，第二子像素为绿色子 像素分别为红色子像素和绿色子像素，由此可以实现RGB彩色显示。
在一个实施方案中，透明色阻单元的亮度改变率在[60％，85％]。
在一个实施方案中，ra在[110％，180％]，rb在[25％，70％]。亮度改变率与发光波长、转化后波长以及光致发光材料的外量子效率等参数相关，并且变动幅度较大。典型地，蓝光向绿光的亮度改变率在25％至70％的范围内，蓝光向红光的亮度改变率为110％至180％的范围内。基于这样的范围，可以计算出x1、x2，进而计算出α 1、α 2，再进而计算出所需的d2+d4 1和d2+d4 2。
作为实例，硒化镉系量子点中，红光量子点的亮度改变率可以为约40％，绿光量子点的亮度改变率可以为约170％。磷化铟系量子点中，红光量子点的亮度改变率可以为约23％，绿光量子点的亮度改变率可以为约110％。
在一个实施方案中，例如，红色子像素的亮度改变率可以约为120％，绿色子像素的亮度改变率可以约为60％，透明色阻单元或光散射单元的亮度改变率可以约为80％。取所有的临界p值均为3％。由于蓝色子像素中没有波长转换单元，不发生光致发光，因此红色子像素和绿色子像素发光向蓝色子像素的串色而不易出现。而在相邻的红色、绿色和蓝色子像素之间，由于红色子像素的亮度改变率高且绿色子像素亮度改变率最低，因此，绿色子像素发光向红色子像素串色最为明显。此时，若假设红色子像素为第一子像素且绿色子像素为第二子像素，则x1％约为3％×(120％/60％)＝6％，x2％约为3％×(60％/120％)＝1.5％。相应地，例如根据前表，例如，α 1对应的角度约为76°，α 2对应的角度约为82°。此时，d4 1的最小值将大于d4 2的最小值。在这种情况下，可以将所有子像素的发光单元顶面与相邻子像素的波长转换单元或透明色阻单元的底面之间的横向距离都设定为82°所对应的d2+d4 1。换言之，只要满足绿色子像素发光不对红色子像素造成明显串色，其他串色均可得到避免。
应当理解，以上实例参数仅是为了说明而非对本公开进行限定。
在实施方案中，本公开的设计也可以用于同色的相邻子像素中。例如，在图1的Y方向上，排列相邻的同色子像素。同色子像素之间的串扰虽然不会造成颜色变化，但也对显示有影响。图10示出了在图2的Y-Z面中 的截面。由于相邻两个子像素a1、a2同色，d4 5和d4 6可以是相等的。此外，相当于转化率相等。而且，对于在Y方向的具有波长转换单元的第二子像素的情况而言，相邻子像素的转化率也相等。因此，对于第一和第二子像素来说，临界光强度占比都相等。在相邻子像素同色时，该占比可以选择得稍大，例如5％，但也可以选择前述的多至p的范围及优选范围。第一子像素之间和第二子像素之间的参数是相同的。至于对于具有透明色阻单元的例如第三子像素，因串扰不明显，因此可以不对其间的几何结构进行限定，但优选与第一和第二子像素尺寸相同。
在一个实施方案中，波长转换单元包含量子点。换言之，波长转换单元可以是量子点波长转换单元。更优选地，发光单元为OLED。由此，形成QD-OLED显示面板。
在一个实施方案中，透明间隔层由下至上包括第一无机层、有机层，和第二无机层。无机-有机-无机的透明间隔层可以是用于封装发光层的封装层，提供良好的综合机械性能和对外界的防护性能，并为后续的第二像素限定层、波长转换层或透明层的制备提供基底，或者用于准备与单独制备的波长转换层对盒。
在一个实施方案中，第一无机层可以是SiNx层，第二无机层可以是是SiONx层或Al 2O 3层。在这样的第一无机层和第二无机层之间夹设有机层可以达到良好的封装效果。无机层的选材和厚度可以适当调节，应兼顾防护性、厚度和本身的强度。
有机层相对于其上下的无机层通常折射率较低，并且导致光线在其中以大角度行进，造成所需的光程很大。减小有机层的厚度有利于减小相邻子像素的距离，从而提高分辨率。
如上所述，通常，透明阴极作为公共电极覆盖在第一像素限定层上。应当理解，在透明阴极与发光单元的发光材料层之间还可以有电子注入层、电子传输层、空穴阻挡层等膜层。若这些膜层整面形成在第一像素限定层上，它们也可以作为透明间隔层的一部分。若这些膜层形成在第一像素限定层之间，则属于单个发光单元。
透明阴极可以使用相关技术中常见的材料。如上所述，金属透明阴极的厚度与透明间隔层相比小很多，因此在前述根据折射率和膜层厚度计算 横向光路距离的公式计算中，可以忽略其存在。
在一个实施方案中，所述有机层的厚度在4至8μm的范围内。这样的厚度较相关技术中常规的厚度低，有利于减少光程。此厚度的有机层可以例如通过喷墨打印方式形成。在这种厚度下，按照本公开的原理，可以得到不串色且具有较高分辨率的显示面板。
在一个实施方案中，所述有机层的厚度在0.3至0.6μm的范围内。这样的厚度较相关技术中大大降低，有利于大幅减少光程，大幅提高分辨率。这样薄层的有机层可以用例如分子层沉积的方式制备。
例如，在一个示例性实施方案中，第一无机层是厚度范围为0.6至1.2μm的SiN，有机层是厚度范围为4至8μm的有机填充层，第二无机层是厚度范围为0.6至1.2μm的SiON。
又例如，在一个示例性实施方案中，第一无机层是厚度范围为0.4至0.7μm的SiN，有机层是厚度范围为0.3至0.6μm的有机层，第二无机层是厚度范围为0.7至1.3μm的Al 2O 3。
本公开利用第二像素限定层的底部限定波长转换单元或透明色阻单元的底面。图11示出了几种常见的第二像素限定层的示意性形状，包括基本上正梯形、基本上矩形和基本上倒梯形。正梯形表示靠近衬底基板一侧的边长较长，倒梯形表示靠近出光侧一侧的边长较长。当然，第二像素限定层也可以是不对称的，但从制备方便角度，对称的第二像素限定层是优选的。
对于具有这些形状的第二像素限定层来说，其与透明间隔层的界面的边界即是其与两侧的波长转换单元或透明色阻单元的边界，并且限定了它们的底面。
在一个实施方案中，第二像素限定层的顶面宽度小于其底面宽度。第二像素限定层之间的波长转换层的出光面大于入光面，有利于显示。
在一个实施方案中，本公开的第二像素限定层可以包括主体部和在所述主体的侧壁上的覆层。主体部的附加覆层可以为波长转换单元带来多方面的优点。
图12示出了侧壁具有侧壁覆层的第二像素限定层的示意图。
波长转换层如QD波长转换层常通过喷墨打印法制备。在On EL式的 路线中，需要在封装层上制作低温固化的第二像素限定层图案，这是由于发光单元不耐高温，当温度超过100℃时，就会出现发光效率、寿命降低等问题。但低温固化的第二像素限定层材料由于固化温度较低，内部仍有大量间隙和孔洞，导致墨水易发生渗透，由一个像素渗透进另一个像素，造成混色，并且由于墨水渗透，第二像素限定层会发生溶胀效应，整体变宽，导致像素开口率下降。为防止第二像素限定层的溶胀效应以及Ink对旁边像素的渗透作用，可以在原有第二像素限定层侧壁上设置墨水渗透防护层。此时，第二像素限定层包括主体部和设置在其侧面的墨水渗透防护层。
覆层也可以是反光层，包括反光材料。覆层还可以是吸光层，包括吸光材料(例如金属钼；或者掺有黑色颜料的树脂，其中黑色颜料可以是苯胺黑、苝黑、钛黑、炭黑、金属氧化物中的一种或多种)反光层的存在可以使射到第二像素限定层侧壁上的未转化的光和转化后的光再次进入波长转化单元内，增强出光效率。反光材料或吸光材料当在透明间隔层的顶面形成如下所述的横向延伸部时，可以对光起到遮挡作用。
优选地，覆层材料为金属层。金属层结构相对致密，可阻挡溶剂，同时具有反光作用。更优选地，可以是使用的金属包括但不限于Al、Ti/Al/Ti、Mo等，它们具备优异的阻挡墨水溶剂的致密性和反光性或吸光性。
在一个实施方案中，所述覆层在底部处具有覆盖所述透明间隔层表面的离开所述主体部的横向延伸部分。
图13示出了在底部具有外延的覆层的结构的示意图。可以看到，墨水渗透防护层，其也可以是反光层，在底部处扩大了第二像素限定层的宽度。这一设计的优点包括以下两点。首先，在没有这种“L”形覆层的情况下，如果为了避免串色而尽量增加第二像素限定层底部宽度的话，第二像素限定层上端将随之变宽，使得波长转换层的发光面积相对变小，或者使波长转换层的体积变小，而这种L形的覆层可以在相同的入光面的情况下使波长转换层具有更大的体积使波长转换更充分，还具有相对更大的出光面积，不会影响分辨率。其次，这种L形的覆层若是墨水渗透防护层，其将增强对主体部底部的保护，使得墨水更难渗透相对薄弱的底部。
在一个更优选的实施方案中，所述主体部具有底切，所述覆层不但覆 盖侧壁，还覆盖所述底切处透明间隔层的顶面，如图13右图所示。
底切是指第二像素限定层的底部相对于顶部凹入，其中底部是靠近衬底基板一侧，顶部是远离衬底基板一侧。典型地，倒梯形的形状即具有底切。虽然理想地想要形成梯形截面，但是由于第二像素限定层材料和工艺限制，实际制成的产品中截面形状常常与标准梯形产生一些偏差。倒梯形的顶角常常不是尖锐角，而是圆角，甚至在实际生产中形成前述的“蘑菇形”的截面，其两个上顶角圆滑化，并且在根部底切深度还有可能有所减少。应当注意，在工艺允许的情况下，应尽量避免产品由梯形产生偏差，即，标准梯形是更为理想的。
在底切中设置的L型的墨水渗透防护层的优点在于可以在低温固化的第二像素限定层上通过溅射随后干刻的方式方便地制备。具体地，所述第二像素限定层通过以下方法制得：光固化获得具有底切的主体，溅射沉积覆盖防护层，再通过干刻除去主体顶面的防护层和底切部位之外的防护层。
图14示出了具有底切和侧壁上的金属墨水渗透防护层的SEM照片。其中，金属墨水渗透防护层均为铝层，图(a)-(d)中铝层的厚度依次为
Figure PCTCN2021096070-appb-000005
Figure PCTCN2021096070-appb-000006
和
Figure PCTCN2021096070-appb-000007
可以看到，金属Al的厚度在
Figure PCTCN2021096070-appb-000008
之间，在干刻后，Al厚度不同，在第二像素限定层侧壁上留下的反光金属形貌和遮挡范围也有所不同。遵照尽可能包覆，防止墨水渗透的原则，Al厚度选择
Figure PCTCN2021096070-appb-000009
比较合适，其他金属遵循相同范围。
可以选用多种金属。对可见光的反射率，由大到小是：Ti/Al/Ti＞Al＞Mo，但由于Al容易被氧化为Al 2O 3，使得反射率降低，所以材料优选Ti/Al/Ti或Ti金属。
优选地，底切深度范围在[4微米，9微米]。底切深度为顶面边缘与底面边缘在衬底基板上投影距离之差，如图13右图中箭头之间的距离u。这样的底切深度可以通过光固化方式形成。当主体部为基本上倒梯形时，其侧面与底面的夹角优选在95°至140°之间。这样的角度保持主体部的强度并且为底切处的墨水渗透防护层留有适量的空间。
显示面板形成工艺可以包括对盒方式和on-EL方式。对盒方式是指分别形成发光层和波长转换层，随后将两者对盒组装。on-EL方式是在发光 层的基础上继续逐层制备波长转换层。本公开的显示面板可以同时使用这两种形成工艺。此外，从波长转换单元/透明色阻单元的制备工艺上分可以包括喷墨打印方式和光刻方式。
本公开的上述说明都基于理想的平直形状。例如截面图中的形状均为矩形或梯形。理想地，第一像素限定层的顶面为平面，并且它们之间的发光单元的顶面是与其平齐的平面；第二像素限定层的底面为平面，并且它们之间的波长转换单元的底面是与其平齐的平面；透明间隔层的底面和顶面相应地也为平面。此外，这些结构的侧壁也都是平坦的。实际生产中，上述各个面都可能不是理想的平面，这些结构的侧壁也可能并不平坦。然而，这些面不应具有过大的起伏。在这些面相对于理想形状仅具有较小起伏的情况下，将其表面拟合为平面后确定前述参数。
本公开还提供包含彩膜层的显示面板。本公开的显示面板还可以包含彩膜层，以提供更好的色彩显示效果。彩膜层设置在波长转换层上。例如，针对红、绿、蓝子像素的对应位置设置红、绿、蓝色滤光单元。
图15示出了还包含彩膜层的本公开的QD-OLED显示面板的一个实施方案的结构示意图。其中，在波长转换层3上，还覆盖彩膜层6和外保护封装层5。彩膜层4可以包括黑矩阵BM和由BM限定的各色彩膜。31为OLED发光单元，11R、11G为红、绿波长转换单元，11B为透明色阻单元，61R、61G、61B为红、绿、蓝色彩膜。
图15仅示出了示意性的基本结构。具体地，透明间隔层2可以包含对发光层的封装层和对波长转换层的封装层，还可以包含在发光层与波长转换层之间的填料层和支撑柱结构。对于波长转换层，封装层有利于其进行对盒组装。图15仅意在说明各个元件的相互位置关系，对各个部件的具体形状和细节不构成限制。
图16示出了发光层相关结构的一个实施方案。图中示出了包含3个完整OLED发光单元和4个PDL-1的局部示意图。衬底基板BS上具有缓冲层BUF。缓冲层上，为每个子像素配置一个TFT单元。TFT单元包括源极S，漏极D，栅极G，有源层ACT。栅极下方与有源层之间为第一栅极绝缘层GI1，栅极周围和上方覆盖第二栅极绝缘层GI2。在第二栅极绝缘层上方依次设有层间介质层ILD和平坦化层PLN。在第二绝缘层和层间 介质层之间还设置有使能信号线Ce1和Ce2。在平坦化层上，第一像素限定层PDL-1之间形成发光单元。发光单元从底侧到顶侧包括包括阳极AD、有机发光部EL和阴极CD。阳极与TFT的漏极相连，阴极为公共电极。在阴极上方，还有第一封装层Encap-1。第一封装层位于发光层靠近波长转换层一侧。图2中示例性示出了，PDL-1是纵截面为梯形的壁。应当理解，其在阵列基板上形成网格，并且限定出许多用于安置发光单元的空间。如上所述的OLED发光单元的结构是本领域已知的，其包括阳极、有机发光层、阴极等。在图17中，发光单元的阳极AD可以是反射阳极，将OLED发出的光向顶面反射，以增加出光效率。此外，与多颜色的OLED阵列不同，本公开的发光层中仅有一种颜色的发光材料层，因此其可以使用Open Mask整面形成，无需使用例如精细金属掩模逐个子像素形成。TFT在衬底基板上的投影可以与PDL-1及发光单元均有重叠。即，TFT也可以部分位于PDL-1之下，另一部分位于反射阳极之下。
本公开提供一种制备上述显示面板的方法，其中，所述第二像素限定层通过以下步骤制得：
获得具有底切的主体部；
在所述透明间隔层和主体部表面溅射沉积覆盖覆层；
通过干刻除去所述主体部顶面的覆层和所述透明间隔层上未被所述主体部顶面遮蔽的部分的所述覆层，保留所述主体部侧壁和所述底切中的所述覆层。
对于有底切的显示面板，通过上述溅射-干刻的方式，可以容易地获得如图13的右图示意性示出的“L”形覆层。在一个实施方案中，通过溅射的方式在第二像素限定层上室温沉积Al、Ti/Al/Ti、Mo等金属，再通过干刻的方式进行垂直刻蚀，倒梯形的侧壁可提供有效的遮挡，使侧壁的金属留下来，倒梯形顶部和像素内金属均被刻掉。倒梯形的顶部没有金属，可防止对环境光的反射。然后再进行氟化氢等离子体轰击，对第二像素限定层顶部进行表面修饰，使其具有疏水疏油的表面性能，以便之后的打印制程。
在一个实施方案中，通过低温固化黑色材料获得所述具有底切的主体部。在On-EL制备工艺中，波长转换层直接形成在发光层和透明间隔层基 底上。因此，为了不使下方的发光单元因高温受损，采用低温固化的第二像素限定层是有利的。但是，低温固化的材料由于固化温度较低，内部仍有大量间隙和孔洞，因此在喷墨打印工艺中导致墨水易发生渗透，由一个像素渗透进另一个像素，造成混色。并且第二像素限定层材料会发生溶胀效应，整体变宽，导致像素开口率下降。
针对此问题，采用低温固化黑色材料特别有利，因为其在固化过程中，底部由于黑色对光的遮挡而固化较差，从而自然形成底切。底切便于形成L形覆层，并且在L形覆层形成后，可以有效阻挡墨水的渗透。
因此，采用低温固化黑色材料获得具有底切的主体部既保护发光单元，又可以方便地制备L形覆层克服孔隙问题。此外，在底切中L形覆层的边缘即波长转换单元的边界可以在干法刻蚀工艺中通过第二像素限定层本身的顶部宽度容易地限定，而无需高精度的掩模等图案化手段。这避免了采用图13的L形覆层横向延伸距离不易控制的问题。
在一个实施方案中，所述透明间隔层包含有机层，通过分子层沉积法制备所述有机层。通过分子层沉积法，与涂布法或喷墨打印法相比，可以获得薄得多的有机层。由于有机材料的折射率通常较低，因此超薄的有机层可以明显减少本公开描述的由临界角出射的光路中光的横向光程，从而可以使第二子像素底面可以更窄，进而获得更高的分辨率。
在另一个实施方案中，本公开还提供包含本公开的显示面板的显示装置，其可以具有良好的防串色性能。
下面结合具体实例对本公开作进一步说明，但本公开并不限于以下实例。
实施例1：
本系列实施例所制备的器件为蓝色OLED叠加QD波长转换单元结构，On EL式路线，将TFT、发光单元和QD波长转换单元制作在一张基板上，本实施例中发光单元的封装层为三层封装结构，约10μm。
背板的层叠结构依次为TFT层、PNL层、阳极ITO/Ag/ITO层、第一像素限定层、蓝光发光层、阴极层、薄膜封装层、低温第二像素限定层层、第二像素限定层侧壁反光金属层、QD波长转换单元层、低温彩膜层，低 温OC层，白玻璃盖板。
基板衬底采用标准方法进行清洗；并进行TFT工序的制备；
用溅射方式沉积一层ITO/Ag/ITO厚度为
Figure PCTCN2021096070-appb-000010
用旋涂的方式涂覆一层光致抗刻蚀材料；经过前烘、曝光、显影、湿刻等工艺条件使ITO/Ag/ITO层图案化；
用旋涂的方式涂覆一层第一像素限定层材料；调节前烘、曝光、显影、后烘，灰化等工艺条件，制备第一像素限定层，厚度在0.5至2.0μm；顶部宽度50μm；
用蒸镀的方式制备蓝色OLED发光层；
使用溅射设备制备MgAg阴极层80至
Figure PCTCN2021096070-appb-000011
用PECVD和喷墨打印(IJP)制作薄膜封装层SiNx 1μm、有机层8μm、SiON 1μm，折射率分别为1.9、1.5和1.8；
用旋涂的方式涂覆低温黑色第二像素限定层主体部材料；调节前烘、曝光、显影、后烘等工艺条件，BM厚度在10至13μm；第二像素限定层主体部图案化时与第一像素限定层顶部宽度相同，固化后形成深度为4至9μm的底切；
用溅射的方式沉积金属Ti/Al/Ti
Figure PCTCN2021096070-appb-000012
再使用ICP干刻的方式进行刻蚀，制作反光金属层；底切处的封装层由反光金属层覆盖，因此第二像素限定层的底面与第一像素限定层顶面同宽；
用IJP的方式打印R/G QD Ink材料以及B像素散射粒子Ink材料；调节前烘、曝光、显影、后烘等工艺条件，厚度在10至12μm；红色与绿色QD层对蓝光的亮度转化率之比为2∶1；
用旋涂的方式涂覆低温RGB CF材料；调节前烘、曝光、显影、后烘等工艺条件，厚度在2μm；
用旋涂的方式涂覆低温低折射率外保护层OC材料(折射率为1.4)；调节前烘、曝光、显影、后烘等工艺条件，厚度在2.0μm；
用白玻璃盖板封装。
按照x1％＝p×(1/2)＝1.55％，根据封装层各层折射率计算光路并除去全反射部分。从封装层底部出发时，出射角为约52°以上的光，将在SiON与有机层界面处全反射，不能从SiON进入有机层。因此，考虑x1％时， 仅取初始出射角0-52°之间的部分。经测试，在本实施例中，出射角在51°至52°之间的光强约占0°至52°之间的总光强的1.55％。按出射角51°计算，其在厚度为1μm的SiON层中横向移动1.2μm。进入有机层时，出射角约为80°，其在厚度为8μm的有机层中横向移动45.4μm。其进入SiNx层后出射角变为55°，其在厚度为1μm的SiNx中横向移动1.4μm。由此算得横向移动总距离为48μm，小于第二像素限定层的底面宽度(50μm)，无法到达相邻子像素的波长转换单元。
根据本公开的方案，可以在不设置额外的竖直阻光层的结构中实现防止串色。
实施例2：
本系列实施例所制备的器件为蓝色OLED叠加QD波长转换单元结构，On EL式路线，将TFT、发光单元和QD波长转换单元制作在一张基板上，本实施例中发光单元的封装层为三层封装结构，约2μm，该结构使用分子层沉积和原子层沉积设备，使膜层更为致密，在保障信赖性的同时，优化减薄EL封装层，根据前面的尺寸设计计算，对比实施例1，本实施例可使设计开口率提升60％以上。
背板的层叠结构依次为TFT层、PNL层、阳极ITO/Ag/ITO层、第一像素限定层、蓝光发光层、阴极层、薄膜封装层、低温第二像素限定层层、第二像素限定层侧壁反光金属层、QD波长转换单元层、低温彩膜层，低温OC层，白玻璃盖板。
基板衬底采用标准方法进行清洗；并进行TFT工序的制备；
用溅射方式沉积一层ITO/Ag/ITO厚度为
Figure PCTCN2021096070-appb-000013
用旋涂的方式涂覆一层光致抗刻蚀材料；经过前烘、曝光、显影、湿刻等工艺条件使ITO/Ag/ITO层图案化；
用旋涂的方式涂覆一层第一像素限定层材料；调节前烘、曝光、显影、后烘，灰化等工艺条件，制备第一像素限定层，厚度在0.5至2.0μm；顶部宽度8μm；
用蒸镀的方式制备蓝色OLED发光层；
使用溅射设备制备MgAg阴极层80至
Figure PCTCN2021096070-appb-000014
用PECVD、分子层沉积(MLD)和原子层沉积(ALD)制作薄膜封装层SiN 0.4至0.7μm、有机层0.3至0.6μm、Al 2O 3 1μm；
用旋涂的方式涂覆低温黑色第二像素限定层主体部材料；调节前烘、曝光、显影、后烘等工艺条件，BM厚度在10至13μm；第二像素限定层主体部图案化时与第一像素限定层顶部宽度相同，固化后形成深度为4至9μm的底切；
用溅射的方式沉积金属Ti/Al/Ti
Figure PCTCN2021096070-appb-000015
再使用ICP干刻的方式进行刻蚀，制作反光金属层；底切处的封装层由反光金属层覆盖，因此第二像素限定层的底面与第一像素限定层顶面同宽；
用IJP的方式打印R/G QD Ink材料以及B像素散射粒子Ink材料；调节前烘、曝光、显影、后烘等工艺条件，厚度在10至12μm；红色与绿色QD层对蓝光的亮度转化率之比为2∶1；
用旋涂的方式涂覆低温RGB CF材料；调节前烘、曝光、显影、后烘等工艺条件，厚度在2μm；
用旋涂的方式涂覆低温低折射率外保护层OC材料(折射率为1.4)；调节前烘、曝光、显影、后烘等工艺条件，厚度在2.0μm；
用白玻璃盖板封装。
类似于实施例1，验证了，从透明间隔层底面以发光占比为1.55％对应的临界角出射的光的横向移动总距离不到4μm，小于第二像素限定层的底面宽度(8μm)，无法到达相邻子像素的波长转换单元。
通过采用分子层沉积答复减小透明间隔层中的低折射率的有机层厚度，可以在良好的分辨率下获得防串色效果。
实施例3：
本系列实施例所制备的器件为蓝色OLED叠加QD波长转换单元结构，On EL式路线，将TFT、发光单元和QD波长转换单元制作在一张基板上，本实施例中发光单元的封装层为三层封装结构，约10μm。第二像素限定层层横截面呈正梯形，此结构更有利于出光。
背板的层叠结构依次为TFT层、PNL层、阳极ITO/Ag/ITO层、第一像素限定层、蓝光发光层、阴极层、薄膜封装层、低温第二像素限定层层、 第二像素限定层侧壁反光金属层、QD波长转换单元层、低温彩膜层，低温OC层，白玻璃盖板。
基板衬底采用标准方法进行清洗；并进行TFT工序的制备；
用溅射方式沉积一层ITO/Ag/ITO厚度为
Figure PCTCN2021096070-appb-000016
用旋涂的方式涂覆一层光致抗刻蚀材料；经过前烘、曝光、显影、湿刻等工艺条件使ITO/Ag/ITO层图案化；
用旋涂的方式涂覆一层第一像素限定层材料；调节前烘、曝光、显影、后烘，灰化等工艺条件，制备第一像素限定层，厚度在0.5至2.0μm；顶部宽度为8μm；
用蒸镀的方式制备蓝色OLED发光层；
使用溅射设备制备MgAg阴极层80至
Figure PCTCN2021096070-appb-000017
用PECVD和IJP制作薄膜封装层SiON 1μm、有机层8μm、SiNx 1μm；
用旋涂的方式涂覆低温黑色第二像素限定层主体部材料；调节前烘、曝光、显影、后烘等工艺条件，BM厚度在10至13μm；第二像素限定层底部与第一像素限定层顶部宽度相同，且其顶部宽度为6微米，形成正梯形截面；
由于无底切，用溅射的方式沉积金属Ti/Al/Ti
Figure PCTCN2021096070-appb-000018
再狭缝涂布的方式涂覆一层光刻胶，曝光显影，光刻胶图案部分保护侧壁金属不被刻蚀，保护范围为整个梯形侧壁，再使用ICP干刻的方式进行刻蚀，刻掉顶部和像素内的金属，制作出侧壁反光金属层；
IJP的方式打印R/G QD Ink材料以及B像素散射粒子Ink材料；调节前烘、曝光、显影、后烘等工艺条件，厚度在10至12μm；红色与绿色QD层对蓝光的亮度转化率之比为2∶1；
用旋涂的方式涂覆低温RGB彩膜材料；调节前烘、曝光、显影、后烘等工艺条件，厚度在2μm；
用旋涂的方式涂覆低温低折射率外保护层OC材料(折射率为1.4)；调节前烘、曝光、显影、后烘等工艺条件，厚度在2.0μm；
用白玻璃盖板封装。
类似于实施例1，验证了，从透明间隔层底面以发光占比为1.55％对 应的临界角出射的光无法到达相邻子像素的波长转换单元。
顶面宽度大于底面宽度的波长转换单元可以更有利于出光。
可见，本公开提供一种显示面板，具有发光层，在发光层上的透明间隔层，和在透明间隔层上的波长转换层，其中根据相邻像素的波长转换单元的亮度改变率和透明间隔层的光路特性，通过将到达相邻子像素的波长转换单元的光强占比控制在一定限度内，至少部分解决波长转换型显示面板的串色问题。
以上所述，仅为本公开的具体实施方式，但本公开的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本公开揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本公开的保护范围之内。因此，本公开的保护范围应以所述权利要求的保护范围为准。

Claims (29)

  1. 一种显示面板，包括：
    在衬底基板上的发光层，
    在所述发光层上的透明间隔层，和
    在所述透明间隔层上的波长转换层，
    其中，所述显示面板包括阵列排布的子像素，所述阵列排布的子像素包含相邻的第一子像素和第二子像素，在所述第一子像素和第二子像素中每一个中，包含一个在所述发光层中的发光单元和一个在所述波长转换层中的波长转换单元，所述发光单元与所述波长转换单元是层叠的并且由所述透明间隔层隔开，
    所述第一子像素和第二子像素的发光单元由所述发光层中的第一像素限定层隔开，且顶面间距为d2，
    所述第一子像素的波长转换单元为第一波长转换单元且对所述发光单元发出的光的亮度改变率为ra，所述第二子像素的波长转换单元为第二波长转换单元且对所述发光单元发出的光的亮度改变率为rb，所述第一子像素和第二子像素的波长转换单元由所述波长转换层中的第二像素限定层隔开，
    在从所述第一子像素到第二子像素的方向上，相对于所述第二子像素的发光单元的顶面与所述第一子像素和第二子像素的发光单元之间的第一像素限定层的边界在所述衬底基板上的正投影，所述第二波长转换单元的底面与所述第一子像素和第二子像素的波长转换单元之间的第二像素限定层的边界在所述衬底基板上的正投影的位移为d4 2，
    其中，
    从所述发光单元顶面入射到所述透明间隔层并且可达到所述透明间隔层的顶面的光中，出射角在α 1以上的光的强度占比为x1％以下，其中，x1％＝p1×(ra/rb)，其中，p1≤5％，
    其中，从所述透明间隔层的底面出发的光当出射角为α 1时，穿过所述透明间隔层的光路在所述衬底基板上的投影的长度小于等于d2+d4 2。
  2. 根据权利要求1所述的显示面板，其中，p1≤2％。
  3. 根据权利要求1所述的显示面板，其中，从所述透明间隔层的底面出发的光当出射角为α 1时，穿过所述透明间隔层的光路在所述衬底基板上的投影的长度与d2+d4 2之差小于等于5μm。
  4. 根据权利要求1所述的显示面板，其中，在从所述第二子像素到第一子像素的方向上，相对于所述第一子像素的发光单元的顶面与所述第一子像素和第二子像素的发光单元之间的第一像素限定层的边界在所述衬底基板上的正投影，所述第一波长转换单元的底面与所述第一子像素和第二子像素的波长转换单元之间的第二像素限定层的边界在所述衬底基板上的正投影的位移为d4 1，
    其中，
    从所述发光单元顶面入射到所述透明间隔层并且可达到所述透明间隔层的顶面的光中，出射角在α 2以上的光的强度占比为x2％以下，其中，x2％＝p2×(rb/ra)，其中，p2≤5％，
    其中，从所述透明间隔层的底面出发的光当出射角为α 2时，穿过所述透明间隔层的光路在所述衬底基板上的投影的长度小于等于d2+d4 1。
  5. 根据权利要求4所述的显示面板，其中，p2＝p1。
  6. 根据权利要求4所述的显示面板，其中，d4 1＝d4 2。
  7. 根据权利要求4所述的显示面板，其中，|d4 1|≤5μm，|d4 2|≤5μm。
  8. 根据权利要求1所述的显示面板，其中，所述透明间隔层的厚度为d1，所述透明间隔层包括由下到上堆叠的m个子层，第i个子层的厚度和折射率分别为L i和n i，i为1至m，
    各参数满足：
    Figure PCTCN2021096070-appb-100001
    Figure PCTCN2021096070-appb-100002
    其中i为1至m的整数，n isinθ 1i为常数且θ 11＝α 1。
  9. 根据权利要求1所述的显示面板，其中，所述阵列排布的子像素还包含第三子像素，所述第一子像素与所述第三子像素相邻，在所述第三子 像素中，包含一个在所述发光层中的发光单元和一个在所述波长转换层中的透明色阻单元，所述发光单元与所述透明色阻单元是层叠的并且由所述透明间隔层隔开，
    所述第一子像素和第三子像素的发光单元由所述发光层中的第一像素限定层隔开，且顶面间距为d5，
    所述透明色阻单元对所述发光单元发出的光不进行波长转换并且亮度改变率为rc，所述第一子像素的波长转换单元和所述第三子像素的透明色阻单元由所述波长转换层中的第二像素限定层隔开，
    在从所述第三子像素到第一子像素的方向上，相对于所述第一子像素的发光单元的顶面与所述第一子像素和第三子像素的发光单元之间的第一像素限定层的边界在所述衬底基板上的正投影，所述第一波长转换单元的底面与所述第一子像素的波长转换单元和第三子像素的透明色阻单元之间的第二像素限定层的边界在所述衬底基板上的正投影的位移为d4 3，
    其中，
    从所述发光单元顶面入射到所述透明间隔层并且可达到所述透明间隔层的顶面的光中，出射角在α 3以上的光的强度占比为x3％以下，其中，x3％＝p3×(rc/ra)，其中，p3≤5％，
    其中，从所述透明间隔层的底面出发的光当出射角为α 3时，穿过所述透明间隔层的光路在所述衬底基板上的投影的长度小于等于d5+d4 3。
  10. 根据权利要求9所述的显示面板，其中，所述发光单元发蓝光，所述第三子像素为蓝色子像素，所述第一子像素为红色子像素，第二子像素为绿色子像素。
  11. 根据权利要求10所述的显示面板，其中，ra在[110％，180％]，rb在[25％，70％]，rc在[60％，85％]。
  12. 根据权利要求1所述的显示面板，其中，所述波长转换单元包含量子点。
  13. 根据权利要求1所述的显示面板，其中，所述透明间隔层包括由下至上层叠的第一无机层、有机层和第二无机层。
  14. 根据权利要求13所述的显示面板，其中，所述第一无机层是SiNx层，所述第二无机层是SiONx层或Al 2O 3层，所述有机层是环氧树脂层或 聚丙烯酸系树脂层。
  15. 根据权利要求13所述的显示面板，其中，所述有机层的厚度在4至8μm的范围内。
  16. 根据权利要求13所述的显示面板，其中，所述有机层的厚度在0.3至0.6μm的范围内。
  17. 根据权利要求1所述的显示面板，其中，所述第二像素限定层的顶面宽度小于其底面宽度。
  18. 根据权利要求1所述的显示面板，其中，所述第二像素限定层包括主体部和在所述主体的侧壁上的覆层。
  19. 根据权利要求18所述的显示面板，其中，所述覆层是墨水渗透防护层。
  20. 根据权利要求18所述的显示面板，其中，所述覆层包括反光材料或吸光材料。
  21. 根据权利要求18所述的显示面板，其中，所述覆层材料为金属。
  22. 根据权利要求18所述的显示面板，其中，所述覆层在底部处具有覆盖所述透明间隔层表面的离开所述主体部的横向延伸部分。
  23. 根据权利要求22所述的显示面板，其中，所述主体部具有底切，所述覆层的所述横向延伸部分覆盖所述底切。
  24. 根据权利要求23所述的显示面板，其中，所述底切的深度在4至9微米的范围内。
  25. 根据权利要求1所述的显示面板，还包括在所述波长转换层上的彩膜层。
  26. 一种制备权利要求1所述的显示面板的方法，其中，所述第二像素限定层通过以下步骤制得：
    获得具有底切的主体部；
    在所述透明间隔层和主体部表面溅射沉积覆盖覆层；
    通过干刻除去所述主体部顶面的覆层和所述透明间隔层上未被所述主体部顶面遮蔽的部分的所述覆层，保留所述主体部侧壁和所述底切中的所述覆层。
  27. 根据权利要求26所述的方法，其中，通过低温固化黑色材料获得 所述具有底切的主体部。
  28. 根据权利要求26所述的方法，其中，所述透明间隔层包含有机层，通过分子层沉积法制备所述有机层。
  29. 一种包含根据权利要求1至25中任一项所述的显示面板或根据权利要求26至28中任一项所述的方法制备的显示面板的显示装置。
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