WO2018014271A1 - An organic light emitting display and a method for manufacturing an organic light emitting display - Google Patents

An organic light emitting display and a method for manufacturing an organic light emitting display Download PDF

Info

Publication number
WO2018014271A1
WO2018014271A1 PCT/CN2016/090770 CN2016090770W WO2018014271A1 WO 2018014271 A1 WO2018014271 A1 WO 2018014271A1 CN 2016090770 W CN2016090770 W CN 2016090770W WO 2018014271 A1 WO2018014271 A1 WO 2018014271A1
Authority
WO
WIPO (PCT)
Prior art keywords
cover layer
refractive index
substrate
light emitting
base polymer
Prior art date
Application number
PCT/CN2016/090770
Other languages
French (fr)
Inventor
Masahide Inoue
Original Assignee
Huawei Technologies Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huawei Technologies Co., Ltd. filed Critical Huawei Technologies Co., Ltd.
Priority to CN201680087739.8A priority Critical patent/CN109844975A/en
Priority to PCT/CN2016/090770 priority patent/WO2018014271A1/en
Publication of WO2018014271A1 publication Critical patent/WO2018014271A1/en

Links

Images

Classifications

    • 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
    • H10K59/877—Arrangements for extracting light from the devices comprising scattering means

Definitions

  • the present invention relates to an organic light emitting display and a method for manufacturing an organic light emitting display.
  • OLED displays are displays using organic light emitting diodes comprising organic compounds as a light emitting material. Since an OLED is advantageous in its light emitting efficiency and its low power consumption, OLED displays are highly expected to be a major trend of next generation display devices.
  • an OLED comprises a first substrate, a cathode electrode layer, an organic light emitting layer, an anode electrode layer, and a second substrate. These layers have a structure separated into pixels of the display.
  • the first and second substrates are composed of glass, a polymer film, or a combination thereof.
  • the glass or the polymer film may include a coating layer.
  • Fig. 8 shows a schematic diagram of an OLED display 400 employing a conventional OLED display cell 410 as described above.
  • Light emitted from an organic light emitting layer 413 of the OLED display 400 passes through a second electrode layer 414 and a second substrate 415 to exit from the OLED display 400 into the environment.
  • the second electrode layer 414 may be an anode electrode made of an electrically conductive material having transparency such as an indium-tin-oxide (ITO) .
  • ITO indium-tin-oxide
  • the material of the second substrate 415 may be a material having transparency such as glass and plastic.
  • Materials of the organic light emitting layer 413, the second electrode layer 414, and the second substrate 415, which compose the OLED display 400 have refractive index which are different from each other and higher than the refractive index of air.
  • the refractive index decreases in the order of the material of the organic light emitting layer, the material of the second electrode layer, the material of the second substrate, and the air.
  • the refractive index of the material of the organic light emitting layer 413, the material of the second electrode layer 414, the material of the second substrate 415, and the air may be about 1.8, about 1.7, about 1.5, and 1.0, respectively. Due to the differences of the refractive index of the materials of the layers, large optical losses occur when light passes through the interfaces of the layers. Such optical losses are further described below.
  • n i is a refractive index of a material of a layer through which light passes
  • ⁇ i is an angle between a normal of a layer and a light travelling direction (an incoming angle and an output angle at an interface)
  • the incoming angle When an output angle ⁇ i is 90 degrees at an interface of layers, the incoming angle is referred to as a critical angle. When the incoming angle is larger than the critical angle, light is not able to pass through the interface but all components of the light are reflected at the interface. Such a phenomenon is referred to as total reflection. Such total reflections may occur at every interface of the layers.
  • the critical angle is derived by applying the refractive index of the materials of the layers to the equation of Snell’s law.
  • Fresnel Fresnel
  • Fig. 10 shows a plot of a simulation result of optical loss for a transmissivity of light passing through the second substrate 415 from the second electrode layer 414 to the air considering the aforementioned reflection and refraction. As shown in Fig. 10, the larger the refractive index becomes, the larger the optical loss for the transmissivity of light passing through the second substrate 415 becomes.
  • PCT International Publication No. WO 2015/053529 proposes a configuration having a concavo-convex interface formed on a surface of a second substrate.
  • United Kingdom Patent Application, Publication No. GB 2,523,859 proposes a configuration of a second substrate including scattering particles. These configurations aim to reduce optical loss at the interface between the second substrate and the air by scattering light having a large output angle before entering the air.
  • a configuration providing an additional layer having a refractive index higher than a refractive index of a material of a second electrode layer 414 between the second electrode layer 414 and a second substrate 415 of the OLED display 400 shown in Fig. 8 is known to those skilled in the art.
  • these configurations have structures in which all of the layers are encapsulated between a first substrate 411 and the second substrate 415, these configurations are generally referred to as “an in-cell configuration” .
  • an in-cell configuration since the refractive index of the material of the second substrate 415 is lower than the refractive index of the material of the additional layer, optical loss still occurs at the interface between the additional layer and the second substrate.
  • the process of forming the layers before encapsulated by the second substrate 415 needs a high degree of cleanliness, the formation of the additional layer must be performed in a clean room, which results in a complicated manufacturing process and high manufacturing cost.
  • the purpose of the present invention is to reduce optical losses at interfaces between layers of such an OLED display and to solve problems due to an in-cell configuration.
  • an organic light emitting display having an on-cell configuration comprising:
  • first cover layer disposed on the organic light emitting diode cell, the first cover layer comprising a first base polymer and scattering particles dispersed in the first base polymer
  • organic light emitting diode cell comprises:
  • a refractive index of the first base polymer is higher than a refractive index of a material of the second substrate
  • a refractive index of a material of the scattering particles is higher than the refractive index of the first base polymer.
  • the first cover layer having the above feature reduces the total reflection and results in the increase of the optical efficiency.
  • a surface of the first cover layer opposing a surface in contact with the second substrate is concavo-convex.
  • the concavo-convex surface of the first cover layer further reduces the total reflection and results in the increase of the optical efficiency.
  • the organic light emitting display further comprises a second cover layer disposed on a surface of the first cover layer opposing a surface in contact with the second substrate, the second cover layer comprising a second base polymer,
  • a refractive index of the second base polymer is lower than the refractive index of the first base polymer
  • the second cover layer having the above feature further reduces the total reflection and results in the increase of the optical efficiency.
  • a surface of the second cover layer opposing a surface in contact with the first cover layer is concavo-convex.
  • the concavo-convex surface of the second cover layer further reduces the total reflection and results in the increase of the optical efficiency.
  • a method of manufacturing an organic light emitting display having an on-cell configuration comprising:
  • an organic light emitting diode cell including: a first substrate; a first electrode layer disposed on the first substrate; an organic light emitting layer disposed on the first electrode layer; a second electrode layer disposed on the organic light emitting layer; and a second substrate disposed on the second electrode layer;
  • a refractive index of the first base polymer is higher than a refractive index of a material of the second substrate
  • a refractive index of a material of the scattering particles is higher than the refractive index of the first base polymer.
  • the first cover layer having the above feature reduces the total reflection and results in the increase of the optical efficiency.
  • a concavo-convex pattern is formed on a surface of the first cover layer in the step of curing the first base polymer to form the first cover layer.
  • the concavo-convex surface of the first cover layer further reduces the total reflection and results in the increase of the optical efficiency.
  • the method further comprises:
  • a refractive index of the second base polymer is lower than the refractive index of the first base polymer
  • the second cover layer having the above feature further reduces the total reflection and results in the increase of the optical efficiency.
  • Fig. 1 shows a cross-sectional diagram of an organic light emitting display according to a first embodiment of the present invention.
  • Fig. 2 shows a simulation result of the relationship between a refractive index of a first base polymer and an optical efficiency regarding transmissivity of light passing through a first cover layer.
  • Fig. 3 shows a simulation result of the relationship between a diffusivity of light scattered by scattering particles and an optical efficiency regarding transmissivity of light passing through the first cover layer.
  • Fig. 4 shows a simulation result of the relationship between a refractive index of the first base polymer, a diffusivity of light scattered by the scattering particles, and an optical efficiency regarding a transmissivity of light passing through the first cover layer.
  • Fig. 5 shows a cross-sectional diagram of an organic light emitting display according to a second embodiment of the present invention.
  • Fig. 6 shows a cross-sectional diagram of an organic light emitting display according to a third embodiment of the present invention.
  • Fig. 7 shows a simulation result of the relationship between a diffusivity of light scattered by the scattering particles and an image quality (blur) of the organic light emission display.
  • Fig. 8 shows a cross-sectional diagram of a conventional organic light emitting display.
  • Fig. 9 shows a simulation result of the relationship between an output angle and an intensity of light.
  • Fig. 10 shows a simulation result of the relationship between a refraction index of a material of a second substrate and an optical loss for a transmissivity of light passing through the second substrate of the conventional organic light emitting display.
  • incoming angle herein indicates an angle between a normal of an interface where light enters and a direction of the incoming light and the term “output angle” indicates an angle between a normal of an interface from which light exits and a direction of the output light. Therefore, light having a small incoming angle enters an interface in a direction closely perpendicular to the interface compared to light having a large incoming angle. Light having a small output angle exits from an interface in a direction closely perpendicular to the interface compared to light having a large output angle.
  • Fig. 1 shows a cross-sectional diagram of an OLED display 100 according to a first embodiment.
  • the OLED display 100 includes an organic light emitting diode (OLED) display cell 110 and a first cover layer 120 disposed on the OLED cell, and the first cover layer 120 includes a first base polymer 122 and scattering particles 121 dispersed in the first base polymer 122.
  • OLED organic light emitting diode
  • the OLED display cell 110 includes: a first substrate 111; a first electrode layer 112 disposed on the first substrate 111; an organic light emitting layer 113 disposed on the first electrode layer 112; a second electrode layer 114 disposed on the organic light emitting layer 113; and a second substrate 115 disposed on the second electrode layer 114.
  • the second electrode layer 114 may be, for example, an anode electrode made of an electrically conductive material having transmissivity such as an indium-tin-oxide (ITO) .
  • the material of the second substrate 115 may be, for example, a material having transmissivity such as glass and a plastic material.
  • a refractive index of the material of the second electrode layer 114 may be lower than a refractive index of the material of the organic light emitting layer 113, and a refractive index of the material of the second substrate 115 may be lower than a refractive index of the material of the second substrate layer 114.
  • the first cover layer 120 is disposed on the second substrate 115 of the OLED display cell 110, and a refractive index of the first base polymer 122 is higher than a refractive index of the material of the second substrate 115.
  • a refractive index of a material of scattering particles 121 is higher than a refractive index of the first base polymer 122.
  • an epoxy resin may be employed as a material of the first base polymer 122.
  • a metal oxide such as a titanium oxide and an aluminum oxide may be employed as a material of the scattering particles 121.
  • the OLED display 100 having such a configuration, light emitted from the organic light emitting layer 113 to the second electrode layer 114 is refracted at an interface between the second electrode layer 114 and the second substrate 115 according to Snell’s law such that the output angle becomes larger.
  • the refractive index of the first base polymer 122 is higher than the refractive index of the material of the second substrate 115, the output angle becomes smaller when light enters the first cover layer 120 including the first base polymer 122 from the second substrate 115. Therefore, the total reflection at the interface between the second substrate 115 and the first cover layer 120 is reduced and thus the optical loss can be reduced.
  • the Snell’s law is described with the following equation:
  • n 1 and n 2 are the refractive indices of the second substrate 115 and the first cover layer 120, respectively, ⁇ 1 is the incoming angle of the second substrate 115, and ⁇ 2 is the output angle of the first cover layer. Since n 2 is larger than n 1 , ⁇ 2 becomes smaller than ⁇ 1 according to the above equation. Larger ⁇ 2 results in reducing the total reflection. Nevertheless, when light enters the air having a low refractive index from the first cover layer 120 including the first base polymer 122 having the high refractive index, total reflection may still occur at the interface between the first cover layer 120 and the air. Furthermore, a Fresnel reflection may occur at the interface as described above. Therefore, optical loss may occur when light passes through the first cover layer 120.
  • the first cover layer 120 includes the scattering particles 121.
  • Light entering the first cover layer 120 is scattered by the scattering particles 121. Since the refractive index of the material of the scattering particles 121 is higher than the refractive index of the first base polymer 122, most of the scattered light travels in a direction in which the incoming angle with respect to the interface between the first cover layer 120 and the air becomes smaller compared with the direction before scattering. Therefore, the total reflection at the interface between the first cover layer 120 and the air is reduced and thus optical loss is reduced. As a result, optical efficiency of the OLED display 100 according to the first embodiment can be increased compared with conventional OLED displays.
  • Fig. 2 shows a plot of a simulation result showing the relationship between the refractive index of the first base polymer 122 included in the first cover layer 120 and the optical efficiency for transmissivity of light passing through the first cover layer 120.
  • the refractive index of the first base polymer 122 becomes higher, the rate of light passing through the first cover layer 120 becomes larger, and therefore the optical efficiency increases.
  • Fig. 3 shows a plot of a simulation result showing the relationship between the diffusivity of light scattered by the scattering particles 121 included in the first cover layer 120 and the optical efficiency for transmissivity of light passing through the first cover layer 120.
  • the diffusivity of light scattered by the scattering particles 121 becomes larger, the rate of light passing through the first cover layer 120 becomes larger, and therefore, the optical efficiency becomes larger.
  • Fig. 4 shows a plot of a simulation result showing the relationship between the diffusivity of light scattered by the scattering particles and the transmissivity of the first cover layer 120 for the first base polymer 122 made of materials having different refractive index.
  • the refractive index of the first base polymer 122 becomes higher, the rate of light passing through the first cover layer 120 becomes larger, and therefore the optical efficiency increases.
  • the diffusivity of light scattered by the scattering particles 121 becomes larger, the rate of light passing through the first cover layer 120 becomes larger, and therefore the optical efficiency increases.
  • the refractive index is larger than 1, negative values of the optical efficiency at a diffusivity equal to zero result from the optical loss due to the effect of Fresnel’s reflection.
  • the optical efficiency increases as the refractive index becomes higher according to the relationship between the refractive index of the first base polymer 122 and the scattering by the scattering particles 121.
  • a method for manufacturing the OLED display 100 having the above configuration according to the first embodiment is as follows:
  • an OLED display cell 110 including: a first substrate 111; a first electrode layer 112 disposed on the first substrate 111; an organic light emitting layer 113 disposed on the first electrode layer 112; a second electrode layer 114 disposed on the organic light emitting layer 113; and a second substrate 115 disposed on the second electrode layer 114.
  • a refractive index of a material of the second electrode layer 114 is lower than a refractive index of a material of the organic light emitting layer 113.
  • a refractive index of a material of the second substrate 115 is lower than the refractive index of the material of the second electrode layer 114.
  • a first base polymer 122 including scattering particles 121 is coated with a predetermined thickness on the second substrate 115.
  • Coating of the first base polymer 122 can be performed by means of a conventional method such as spin-coating, slit-coating, spray-coating, and screen-printing.
  • a refractive index of the first base polymer 122 is higher than the refractive index of the material of the second substrate 115.
  • a refractive index of a material of the scattering particles 121 is higher than the refractive index of the first base polymer 122.
  • a first cover layer 120 is formed by curing the first base polymer 122 to obtain the OLED display 100.
  • Curing of the first base polymer 122 can be performed by means of a conventional method such as thermal curing and UV curing.
  • Such a configuration having a first cover layer including scattering particles for reducing optical loss disposed on a second substrate of an OLED display cell is referred to as an “on-cell configuration” .
  • a first cover layer of an OLED display cell having an on-cell configuration can be disposed on a second substrate after first and second substrates encapsulate a first electrode layer, an organic light emitting layer, and a second electrode layer.
  • the first cover layer since forming a first cover layer does not need an environment as high grade clean as the environment necessary for forming the first electrode layer, the organic light emitting layer, and the second electrode layer, the first cover layer does not need to be formed in a high grade clean room. Therefore, the process for forming the first cover layer is simple and the cost is low.
  • the first cover layer is formed after forming the OLED display cell, the first cover layer is not exposed to a thermal and chemical substances applied in the process for forming the OLED display cell. Therefore, the first base polymer composing the first cover layer does not need to have thermal durability and chemical durability. Furthermore, the first cover layer can be easily applied to an existing OLED display cell. Instead of applying the first cover layer, a film having a refraction characteristic and a scattering characteristic similar to the first cover layer may be separately manufactured and laminated on the second substrate. However, such a manufacturing method has problems of high cost and contamination of dust in the lamination process, but also thicker than coating in general . Coating the first base polymer to form the first cover layer can avoid such problems.
  • a component to increase the optical efficiency such as the first cover layer has to be formed in an OLED display cell. Since a process for forming a component to increase the optical efficiency has to be performed in a clean environment such as a clean room, the process becomes more complicated and the manufacturing cost increases.
  • Fig. 5 shows a cross-sectional diagram of an OLED display 200 according to a second embodiment.
  • the OLED display 200 includes an OLED display cell 210 and a first cover layer 220 similar to the OLED display 100 according to the first embodiment.
  • the OLED display cell 210 includes: a first substrate 211; a first electrode layer 212; an organic light emitting layer 213; a second electrode 214; and a second substrate 215.
  • a first cover layer 220 is disposed on the second substrate 215 and includes a first base polymer 222 and scattering particles 221.
  • a refractive index of the first base polymer 222 is higher than a refractive index of a material of the second substrate 215.
  • a refractive index of a material of the scattering particles 221 is higher than the refractive index of the first base polymer 222.
  • a concavo-convex pattern 223 is formed on a surface of the first cover layer 220.
  • the OLED display 200 having such a configuration, light emitted from the organic light emitting layer 213 and passing through the second electrode 214 and the second substrate 215 is refracted at an interface between the second substrate 215 and the first cover layer 220 according to Snell’s law such that the output angle becomes smaller.
  • Light entering the first cover layer 220 is scattered by the scattering particles 221. Since the refractive index of the material of the scattering particles 221 is higher than the refractive index of the first base polymer 222, most of the scattered light travels in a direction in which the incoming angle with respect to the surface of the first cover layer 220 becomes smaller compared with the incoming angle before scattering.
  • the first cover layer 220 of the second embodiment has two scattering modes: one is an internal scattering mode by the scattering particles 221; the other is a surface scattering mode by the concavo-convex pattern 223 on the surface.
  • the internal scattering mode by the scattering particles 221 changes the direction of light to reduce the total reflection at an interface between the first cover layer 220 and the air and therefore reduces optical loss.
  • the surface scattering mode increases the rate of light perpendicular to the interface between the first cover layer 220 and the air and therefore increases the brightness.
  • the OLED display 200 according to the second embodiment has an increased optical efficiency compared with conventional OLED displays.
  • Fig. 6 shows a cross-sectional diagram of an OLED display 300 according to a third embodiment.
  • the OLED display 300 includes an OLED display cell 310 and a first cover layer 320 similar to the OLED display 200 according to the second embodiment.
  • the OLED display 300 according to the third embodiment further comprises a second cover layer 330 on the first cover layer 320.
  • the OLED display cell 310 includes: a first substrate 311; a first electrode layer 312; an organic light emitting layer 313; a second electrode layer 314; and a second substrate 315.
  • the first cover layer 320 is disposed on the second substrate 315 and includes a first base polymer 322 and scattering particles 321.
  • a refractive index of the first base polymer 322 is higher than a refractive index of a material of the second substrate 315.
  • a refractive index of a material of the scattering particles 321 is higher than the refractive index of the first base polymer 322.
  • a concavo-convex pattern 323 is formed on a surface of the first cover layer 320.
  • the second cover layer 330 is disposed on the first cover layer 320 and includes a second base polymer 332.
  • a refractive index of the second base polymer 332 is lower than the refractive index of the first base polymer 322.
  • the OLED display 300 In the OLED display 300 according to the third embodiment having such a configuration, light emitted from the organic light emitting layer 313 and passing through the second electrode layer 314 and the second substrate 315 is refracted at an interface between the second substrate 315 and the first cover layer 320 according to Snell’s law such that the output angle becomes smaller.
  • Light entering the first cover layer 320 is scattered by the scattering particles 321. Since the refractive index of the material of the scattering particles 321 is higher than the refractive index of the first base polymer 322, most of the scattered light travels in a direction in which the incoming angle with respect to the surface of the first cover layer 320 becomes smaller compared with the incoming angle before scattering.
  • Light coming at the surface of the first cover layer 320 is scattered by the concavo-convex pattern 323 on the surface of the first cover layer 320 in a direction in which the output angle becomes smaller.
  • the concavo-convex pattern 323 can be formed by means of a conventional method such as scratch and nanoimprinting in a step of forming the first cover layer 320.
  • a material or a process can be selected such that the concavo-convex pattern 323 is formed when curing the material of the first cover layer 320 itself.
  • Such a concavo-convex pattern is spontaneously formed since rates of shrinkage of the scattering particles 321 are different from a rate of shrinkage of the first base polymer 322 which compose the first cover layer, or since shapes of the scattering particles 321 appear on the surface of the first cover layer 320 when the first cover layer 320 is formed as a thin film if a viscosity of the first base polymer 322 is low.
  • the second cover layer 330 is disposed on the first cover layer 320.
  • the output angle of light at the interface between the first cover layer 320 and the second cover layer 330 is smaller than the output angle of light at the interface between the first cover layer 220 of the OLED display 200 according to the second embodiment and the air. Therefore, the total reflection at the interface between the first cover layer 320 and the second cover layer 330 can be reduced, and thus the optical loss can be reduced. As a result, the OLED display 300 according to the third embodiment has an increased optical efficiency compared with conventional OLED displays.
  • Disposing the second cover layer 330 without forming the concavo-convex pattern on the surface of the first cover layer 320 may also reduce the total reflection at the interface between the first cover layer 320 and the second cover layer 330 and reduce the optical loss.
  • the OLED display 300 has an increased optical efficiency compared with conventional OLED displays.
  • the second cover layer 330 can be formed by coating the second base polymer by means of a conventional method such as spin-coating, slit-coating, spray-coating, and screen-coating, and then by curing the second base polymer by means of a conventional method such as thermal curing and UV curing similarly to the first cover layer 320.
  • Fig. 7 shows a plot of a simulation result of the relationship between the diffusivity of light due to the scattering particles in the first cover layer and the concavo-convex pattern on the surface of the first cover layer and blur of an image obtained by the OLED display.
  • scattering of light by the scattering particles and the concavo-convex pattern on the surface increases the optical efficiency of the OLED display.
  • the diffusivity becomes larger, the blur of the obtained image becomes larger. Larger blur of an image leads to a degradation of image quality.
  • the diffusivity is determined, for example, by changing the concentration of the scattering particles in the first cover layer.
  • a concentration of scattering particles in a first cover layer and a concavo-convex pattern on a surface of a first cover layer have to be determined in order that both quality of an obtained image and optical efficiency fall within a preferred range.

Landscapes

  • Electroluminescent Light Sources (AREA)

Abstract

An organic light emitting display (100) having an on-cell configuration, comprises: an organic light emitting diode cell (110); and a first cover layer (120) disposed on the organic light emitting diode cell (110), the first cover layer (120) comprises a first base polymer (122) and scattering particles (121) dispersed in the first base polymer (122), wherein the organic light emitting diode cell (110) comprises: a first substrate (111); a first electrode layer (112) disposed on the first substrate (111); an organic light emitting layer (113) disposed on the first electrode layer (112);a second electrode layer (114) disposed on the organic light emitting layer (113); and a second substrate (115) disposed on the second electrode layer (114), wherein the first cover layer (120) is disposed on the second substrate (115), wherein a refractive index of the first base polymer (122) is higher than a refractive index of a material of the second substrate (115), and wherein a refractive index of a material of the scattering particles (121) is higher than the refractive index of the first base polymer (122).

Description

AN ORGANIC LIGHT EMITTING DISPLAY AND A METHOD FOR MANUFACTURING AN ORGANIC LIGHT EMITTING DISPLAY
Field of Invention
The present invention relates to an organic light emitting display and a method for manufacturing an organic light emitting display.
Background of the Invention
Organic light emitting diode (OLED) displays are displays using organic light emitting diodes comprising organic compounds as a light emitting material. Since an OLED is advantageous in its light emitting efficiency and its low power consumption, OLED displays are highly expected to be a major trend of next generation display devices.
In general, an OLED comprises a first substrate, a cathode electrode layer, an organic light emitting layer, an anode electrode layer, and a second substrate. These layers have a structure separated into pixels of the display. The first and second substrates are composed of glass, a polymer film, or a combination thereof. The glass or the polymer film may include a coating layer. The above configuration is, in general, referred to as “an OLED display cell” .
Fig. 8 shows a schematic diagram of an OLED display 400 employing a conventional OLED display cell 410 as described above. Light emitted from an organic light emitting layer 413 of the OLED display 400 passes through a second electrode layer 414 and a second substrate 415 to exit from the OLED display 400 into the environment. The second electrode layer 414 may be an anode electrode made of an electrically conductive material having transparency such as an indium-tin-oxide (ITO) . The material of the second substrate 415 may be a material having transparency such as glass and plastic. Materials of the organic light emitting layer 413, the second electrode layer 414, and the second substrate 415, which compose the OLED display 400, have refractive index which are different from each other and higher than the refractive index of air. In general, the refractive index decreases in the order of the material of the organic light emitting layer, the material of the second electrode layer, the material of the second substrate, and the air. For example, the refractive index of the material of the organic light emitting layer 413, the material of the second electrode layer 414, the material of the second substrate 415, and the air may be about  1.8, about 1.7, about 1.5, and 1.0, respectively. Due to the differences of the refractive index of the materials of the layers, large optical losses occur when light passes through the interfaces of the layers. Such optical losses are further described below.
In Fig. 8, Snell’s law is described with the following equation:
n1 Sinθ1＝ n2 Sinθ2＝ n3 Sinθ3＝ n4 Sinθ4,
where ni is a refractive index of a material of a layer through which light passes, θi is an angle between a normal of a layer and a light travelling direction (an incoming angle and an output angle at an interface) , an index of i ＝ 1 corresponds to the organic light emitting layer, i ＝ 2 corresponds to the second electrode layer, i ＝ 3 corresponds to the second substrate, and i ＝ 4 corresponds to the air.
When an output angle θi is 90 degrees at an interface of layers, the incoming angle is referred to as a critical angle. When the incoming angle is larger than the critical angle, light is not able to pass through the interface but all components of the light are reflected at the interface. Such a phenomenon is referred to as total reflection. Such total reflections may occur at every interface of the layers. The critical angle is derived by applying the refractive index of the materials of the layers to the equation of Snell’s law.
Optical losses at interfaces due to such total reflections result from the differences between the refractive index of the materials of the layers. According to Snell’s law, an output angle becomes larger than an incoming angle when light enters a material having a low refractive index from a material having a high refractive index. As discussed above, the refractive index of the layers of the conventional OLED display 400 decrease in the order of the material of the organic light emitting layer 413, the material of the second electrode layer 414, the material of the second substrate 415, and the air. Therefore, when light passes through the interfaces between the layers, the incoming angle and the output angle become larger. As shown in Fig. 9, when the output angle is large, the intensity of the output light is reduced, and thus optical loss occurs at the interface of the layers. When the incoming angle exceeds the critical angle, light totally reflects at the interface and therefore does not exit from the OLED display.
At an interface between layers having different refractive index, a reflection and a refraction can occur other than the refraction and the total reflection due to aforementioned Snell’s law. Such a reflection and a refraction are referred to as Fresnel’s reflection. Fresnel’s reflection follows the equations shown below.
Figure PCTCN2016090770-appb-000001
Figure PCTCN2016090770-appb-000002
where Rs and Rp indicate reflectivities of S and P polarizations, respectively.
Fig. 10 shows a plot of a simulation result of optical loss for a transmissivity of light passing through the second substrate 415 from the second electrode layer 414 to the air considering the aforementioned reflection and refraction. As shown in Fig. 10, the larger the refractive index becomes, the larger the optical loss for the transmissivity of light passing through the second substrate 415 becomes.
To solve the problem of optical loss at an interface, PCT International Publication No. WO 2015/053529 proposes a configuration having a concavo-convex interface formed on a surface of a second substrate. United Kingdom Patent Application, Publication No. GB 2,523,859 proposes a configuration of a second substrate including scattering particles. These configurations aim to reduce optical loss at the interface between the second substrate and the air by scattering light having a large output angle before entering the air. Furthermore, a configuration providing an additional layer having a refractive index higher than a refractive index of a material of a second electrode layer 414 between the second electrode layer 414 and a second substrate 415 of the OLED display 400 shown in Fig. 8 is known to those skilled in the art. Since these configurations have structures in which all of the layers are encapsulated between a first substrate 411 and the second substrate 415, these configurations are generally referred to as “an in-cell configuration” . In an OLED display having an in-cell configuration, since the refractive index of the material of the second substrate 415 is lower than the refractive index of the material of the additional layer, optical loss still occurs at the interface between the additional layer and the second substrate. Furthermore, since the process of forming the layers before encapsulated by the second substrate 415 needs a high degree of cleanliness, the formation of the additional layer must be performed in a clean room, which results in a complicated manufacturing process and high manufacturing cost. Since the encapsulation by the second substrate is performed after forming the additional layer, a material having thermal durability and chemical durability must be employed as the additional layer in order to avoid damage in the process. Furthermore, since the methods disclosed in PCT International Publication No. WO 2015/053529 and United Kingdom Patent Application, Publication No. GB 2,523,859 need fabrication of the second substrate itself, the manufacturing process becomes more complicated and the manufacturing cost becomes higher.
The purpose of the present invention is to reduce optical losses at interfaces  between layers of such an OLED display and to solve problems due to an in-cell configuration.
Summary of the Invention
According to an aspect of the present invention, an organic light emitting display having an on-cell configuration is provided, the organic light emission display comprising:
an organic light emitting diode cell； and
a first cover layer disposed on the organic light emitting diode cell, the first cover layer comprising a first base polymer and scattering particles dispersed in the first base polymer,
wherein the organic light emitting diode cell comprises:
a first substrate；
a first electrode layer disposed on the first substrate；
an organic light emitting layer disposed on the first electrode layer；
a second electrode layer disposed on the organic light emitting layer； and
a second substrate disposed on the second electrode layer,
wherein the first cover layer is disposed on the second substrate,
wherein a refractive index of the first base polymer is higher than a refractive index of a material of the second substrate, and
wherein a refractive index of a material of the scattering particles is higher than the refractive index of the first base polymer.
The first cover layer having the above feature reduces the total reflection and results in the increase of the optical efficiency.
In an aspect of the present application, a surface of the first cover layer opposing a surface in contact with the second substrate is concavo-convex.
The concavo-convex surface of the first cover layer further reduces the total reflection and results in the increase of the optical efficiency.
In an aspect of the present invention, the organic light emitting display further comprises a second cover layer disposed on a surface of the first cover layer opposing a surface in contact with the second substrate, the second cover layer comprising a second base polymer,
wherein a refractive index of the second base polymer is lower than the refractive index of the first base polymer.
The second cover layer having the above feature further reduces the total  reflection and results in the increase of the optical efficiency.
In an aspect of the present application, a surface of the second cover layer opposing a surface in contact with the first cover layer is concavo-convex.
The concavo-convex surface of the second cover layer further reduces the total reflection and results in the increase of the optical efficiency.
According to an aspect of the present invention, a method of manufacturing an organic light emitting display having an on-cell configuration is provided, the method comprising:
providing an organic light emitting diode cell including: a first substrate； a first electrode layer disposed on the first substrate； an organic light emitting layer disposed on the first electrode layer； a second electrode layer disposed on the organic light emitting layer； and a second substrate disposed on the second electrode layer；
coating a first base polymer on the second substrate, the first base polymer including scattering particles； and
curing the first base polymer to form a first cover layer,
wherein a refractive index of the first base polymer is higher than a refractive index of a material of the second substrate, and
wherein a refractive index of a material of the scattering particles is higher than the refractive index of the first base polymer.
The first cover layer having the above feature reduces the total reflection and results in the increase of the optical efficiency.
In an aspect of the present invention, a concavo-convex pattern is formed on a surface of the first cover layer in the step of curing the first base polymer to form the first cover layer.
The concavo-convex surface of the first cover layer further reduces the total reflection and results in the increase of the optical efficiency.
In an aspect of the present invention, the method further comprises:
coating a second base polymer on the first cover layer； and
curing the second base polymer to form a second cover layer,
wherein a refractive index of the second base polymer is lower than the refractive index of the first base polymer.
The second cover layer having the above feature further reduces the total reflection and results in the increase of the optical efficiency.
Brief Description of the Drawings
To describe the technical solutions in the embodiments of the present invention or in the prior art more clearly, the following briefly introduces the accompanying drawings required for describing the embodiments or the prior art.
Fig. 1 shows a cross-sectional diagram of an organic light emitting display according to a first embodiment of the present invention.
Fig. 2 shows a simulation result of the relationship between a refractive index of a first base polymer and an optical efficiency regarding transmissivity of light passing through a first cover layer.
Fig. 3 shows a simulation result of the relationship between a diffusivity of light scattered by scattering particles and an optical efficiency regarding transmissivity of light passing through the first cover layer.
Fig. 4 shows a simulation result of the relationship between a refractive index of the first base polymer, a diffusivity of light scattered by the scattering particles, and an optical efficiency regarding a transmissivity of light passing through the first cover layer.
Fig. 5 shows a cross-sectional diagram of an organic light emitting display according to a second embodiment of the present invention.
Fig. 6 shows a cross-sectional diagram of an organic light emitting display according to a third embodiment of the present invention.
Fig. 7 shows a simulation result of the relationship between a diffusivity of light scattered by the scattering particles and an image quality (blur) of the organic light emission display.
Fig. 8 shows a cross-sectional diagram of a conventional organic light emitting display.
Fig. 9 shows a simulation result of the relationship between an output angle and an intensity of light.
Fig. 10 shows a simulation result of the relationship between a refraction index of a material of a second substrate and an optical loss for a transmissivity of light passing through the second substrate of the conventional organic light emitting display.
Detailed Description of the Embodiments
The term “incoming angle” herein indicates an angle between a normal of an interface where light enters and a direction of the incoming light and the term “output angle” indicates an angle between a normal of an interface from which light exits and a direction of the output light. Therefore, light having a small incoming angle enters an  interface in a direction closely perpendicular to the interface compared to light having a large incoming angle. Light having a small output angle exits from an interface in a direction closely perpendicular to the interface compared to light having a large output angle.
Fig. 1 shows a cross-sectional diagram of an OLED display 100 according to a first embodiment. The OLED display 100 includes an organic light emitting diode (OLED) display cell 110 and a first cover layer 120 disposed on the OLED cell, and the first cover layer 120 includes a first base polymer 122 and scattering particles 121 dispersed in the first base polymer 122.
The OLED display cell 110 includes: a first substrate 111； a first electrode layer 112 disposed on the first substrate 111； an organic light emitting layer 113 disposed on the first electrode layer 112； a second electrode layer 114 disposed on the organic light emitting layer 113； and a second substrate 115 disposed on the second electrode layer 114. The second electrode layer 114 may be, for example, an anode electrode made of an electrically conductive material having transmissivity such as an indium-tin-oxide (ITO) . The material of the second substrate 115 may be, for example, a material having transmissivity such as glass and a plastic material. A refractive index of the material of the second electrode layer 114 may be lower than a refractive index of the material of the organic light emitting layer 113, and a refractive index of the material of the second substrate 115 may be lower than a refractive index of the material of the second substrate layer 114.
The first cover layer 120 is disposed on the second substrate 115 of the OLED display cell 110, and a refractive index of the first base polymer 122 is higher than a refractive index of the material of the second substrate 115. A refractive index of a material of scattering particles 121 is higher than a refractive index of the first base polymer 122. For example, an epoxy resin may be employed as a material of the first base polymer 122. For example, a metal oxide such as a titanium oxide and an aluminum oxide may be employed as a material of the scattering particles 121.
In the OLED display 100 having such a configuration, light emitted from the organic light emitting layer 113 to the second electrode layer 114 is refracted at an interface between the second electrode layer 114 and the second substrate 115 according to Snell’s law such that the output angle becomes larger. However, since the refractive index of the first base polymer 122 is higher than the refractive index of the material of the second substrate 115, the output angle becomes smaller when light enters the first cover layer 120 including the first base polymer 122 from the second substrate 115. Therefore, the total reflection at the interface between the second substrate 115 and the  first cover layer 120 is reduced and thus the optical loss can be reduced. At the interface between the second substrate 115 and the first cover layer 120, the Snell’s law is described with the following equation:
n1 Sinθ1 ＝ n2 Sinθ2
where n1 and n2 are the refractive indices of the second substrate 115 and the first cover layer 120, respectively, θ1 is the incoming angle of the second substrate 115, and θ2 is the output angle of the first cover layer. Since n2 is larger than n1, θ2 becomes smaller than θ1 according to the above equation. Larger θ2 results in reducing the total reflection. Nevertheless, when light enters the air having a low refractive index from the first cover layer 120 including the first base polymer 122 having the high refractive index, total reflection may still occur at the interface between the first cover layer 120 and the air. Furthermore, a Fresnel reflection may occur at the interface as described above. Therefore, optical loss may occur when light passes through the first cover layer 120.
To reduce such an optical loss, the first cover layer 120 includes the scattering particles 121. Light entering the first cover layer 120 is scattered by the scattering particles 121. Since the refractive index of the material of the scattering particles 121 is higher than the refractive index of the first base polymer 122, most of the scattered light travels in a direction in which the incoming angle with respect to the interface between the first cover layer 120 and the air becomes smaller compared with the direction before scattering. Therefore, the total reflection at the interface between the first cover layer 120 and the air is reduced and thus optical loss is reduced. As a result, optical efficiency of the OLED display 100 according to the first embodiment can be increased compared with conventional OLED displays.
Fig. 2 shows a plot of a simulation result showing the relationship between the refractive index of the first base polymer 122 included in the first cover layer 120 and the optical efficiency for transmissivity of light passing through the first cover layer 120. As shown in Fig. 2, as the refractive index of the first base polymer 122 becomes higher, the rate of light passing through the first cover layer 120 becomes larger, and therefore the optical efficiency increases.
Fig. 3 shows a plot of a simulation result showing the relationship between the diffusivity of light scattered by the scattering particles 121 included in the first cover layer 120 and the optical efficiency for transmissivity of light passing through the first cover layer 120. As shown in Fig. 3, as the diffusivity of light scattered by the scattering particles 121 becomes larger, the rate of light passing through the first cover layer 120 becomes larger, and therefore, the optical efficiency becomes larger.
Fig. 4 shows a plot of a simulation result showing the relationship between the diffusivity of light scattered by the scattering particles and the transmissivity of the first cover layer 120 for the first base polymer 122 made of materials having different refractive index. As shown in Fig. 4, as the refractive index of the first base polymer 122 becomes higher, the rate of light passing through the first cover layer 120 becomes larger, and therefore the optical efficiency increases. As the diffusivity of light scattered by the scattering particles 121 becomes larger, the rate of light passing through the first cover layer 120 becomes larger, and therefore the optical efficiency increases. When the refractive index is larger than 1, negative values of the optical efficiency at a diffusivity equal to zero result from the optical loss due to the effect of Fresnel’s reflection. Therefore, simply increasing the refractive index of the first base polymer without employing the scattering particle leads to a decrease in the optical efficiency. However, as the diffusivity of light increases due to the scattered particles 121 included in the first cover layer 120 of the OLED display 100 according to the first embodiment, the optical efficiency increases as the refractive index becomes higher according to the relationship between the refractive index of the first base polymer 122 and the scattering by the scattering particles 121.
A method for manufacturing the OLED display 100 having the above configuration according to the first embodiment is as follows:
In a first step, an OLED display cell 110 is provided, the OLED display cell 110 including: a first substrate 111； a first electrode layer 112 disposed on the first substrate 111； an organic light emitting layer 113 disposed on the first electrode layer 112； a second electrode layer 114 disposed on the organic light emitting layer 113； and a second substrate 115 disposed on the second electrode layer 114. A refractive index of a material of the second electrode layer 114 is lower than a refractive index of a material of the organic light emitting layer 113. A refractive index of a material of the second substrate 115 is lower than the refractive index of the material of the second electrode layer 114.
In a second step, a first base polymer 122 including scattering particles 121 is coated with a predetermined thickness on the second substrate 115. Coating of the first base polymer 122 can be performed by means of a conventional method such as spin-coating, slit-coating, spray-coating, and screen-printing. A refractive index of the first base polymer 122 is higher than the refractive index of the material of the second substrate 115. A refractive index of a material of the scattering particles 121 is higher than the refractive index of the first base polymer 122.
In a third step, a first cover layer 120 is formed by curing the first base polymer  122 to obtain the OLED display 100. Curing of the first base polymer 122 can be performed by means of a conventional method such as thermal curing and UV curing.
Such a configuration having a first cover layer including scattering particles for reducing optical loss disposed on a second substrate of an OLED display cell is referred to as an “on-cell configuration” . A first cover layer of an OLED display cell having an on-cell configuration can be disposed on a second substrate after first and second substrates encapsulate a first electrode layer, an organic light emitting layer, and a second electrode layer. In this case, since forming a first cover layer does not need an environment as high grade clean as the environment necessary for forming the first electrode layer, the organic light emitting layer, and the second electrode layer, the first cover layer does not need to be formed in a high grade clean room. Therefore, the process for forming the first cover layer is simple and the cost is low. Since the first cover layer is formed after forming the OLED display cell, the first cover layer is not exposed to a thermal and chemical substances applied in the process for forming the OLED display cell. Therefore, the first base polymer composing the first cover layer does not need to have thermal durability and chemical durability. Furthermore, the first cover layer can be easily applied to an existing OLED display cell. Instead of applying the first cover layer, a film having a refraction characteristic and a scattering characteristic similar to the first cover layer may be separately manufactured and laminated on the second substrate. However, such a manufacturing method has problems of high cost and contamination of dust in the lamination process, but also thicker than coating in general . Coating the first base polymer to form the first cover layer can avoid such problems.
On the other hand, in an OLED display having a conventional in-cell configuration, a component to increase the optical efficiency such as the first cover layer has to be formed in an OLED display cell. Since a process for forming a component to increase the optical efficiency has to be performed in a clean environment such as a clean room, the process becomes more complicated and the manufacturing cost increases.
Fig. 5 shows a cross-sectional diagram of an OLED display 200 according to a second embodiment. The OLED display 200 includes an OLED display cell 210 and a first cover layer 220 similar to the OLED display 100 according to the first embodiment. The OLED display cell 210 includes: a first substrate 211； a first electrode layer 212； an organic light emitting layer 213； a second electrode 214； and a second substrate 215. A first cover layer 220 is disposed on the second substrate 215 and includes a first base polymer 222 and scattering particles 221. A refractive index of the first base polymer  222 is higher than a refractive index of a material of the second substrate 215. A refractive index of a material of the scattering particles 221 is higher than the refractive index of the first base polymer 222. A concavo-convex pattern 223 is formed on a surface of the first cover layer 220.
In the OLED display 200 having such a configuration, light emitted from the organic light emitting layer 213 and passing through the second electrode 214 and the second substrate 215 is refracted at an interface between the second substrate 215 and the first cover layer 220 according to Snell’s law such that the output angle becomes smaller. Light entering the first cover layer 220 is scattered by the scattering particles 221. Since the refractive index of the material of the scattering particles 221 is higher than the refractive index of the first base polymer 222, most of the scattered light travels in a direction in which the incoming angle with respect to the surface of the first cover layer 220 becomes smaller compared with the incoming angle before scattering. Light coming at the surface of the first cover layer 220 is scattered by the concavo-convex pattern 223 on the surface of the first cover layer 220 in a direction in which the output angle becomes smaller. In other words, the first cover layer 220 of the second embodiment has two scattering modes: one is an internal scattering mode by the scattering particles 221； the other is a surface scattering mode by the concavo-convex pattern 223 on the surface. The internal scattering mode by the scattering particles 221 changes the direction of light to reduce the total reflection at an interface between the first cover layer 220 and the air and therefore reduces optical loss. The surface scattering mode increases the rate of light perpendicular to the interface between the first cover layer 220 and the air and therefore increases the brightness. As a result, the OLED display 200 according to the second embodiment has an increased optical efficiency compared with conventional OLED displays.
Fig. 6 shows a cross-sectional diagram of an OLED display 300 according to a third embodiment. The OLED display 300 includes an OLED display cell 310 and a first cover layer 320 similar to the OLED display 200 according to the second embodiment. The OLED display 300 according to the third embodiment further comprises a second cover layer 330 on the first cover layer 320. The OLED display cell 310 includes: a first substrate 311； a first electrode layer 312； an organic light emitting layer 313； a second electrode layer 314； and a second substrate 315. The first cover layer 320 is disposed on the second substrate 315 and includes a first base polymer 322 and scattering particles 321. A refractive index of the first base polymer 322 is higher than a refractive index of a material of the second substrate 315. A refractive index of a material of the scattering particles 321 is higher than the refractive  index of the first base polymer 322. A concavo-convex pattern 323 is formed on a surface of the first cover layer 320. The second cover layer 330 is disposed on the first cover layer 320 and includes a second base polymer 332. A refractive index of the second base polymer 332 is lower than the refractive index of the first base polymer 322.
In the OLED display 300 according to the third embodiment having such a configuration, light emitted from the organic light emitting layer 313 and passing through the second electrode layer 314 and the second substrate 315 is refracted at an interface between the second substrate 315 and the first cover layer 320 according to Snell’s law such that the output angle becomes smaller. Light entering the first cover layer 320 is scattered by the scattering particles 321. Since the refractive index of the material of the scattering particles 321 is higher than the refractive index of the first base polymer 322, most of the scattered light travels in a direction in which the incoming angle with respect to the surface of the first cover layer 320 becomes smaller compared with the incoming angle before scattering. Light coming at the surface of the first cover layer 320 is scattered by the concavo-convex pattern 323 on the surface of the first cover layer 320 in a direction in which the output angle becomes smaller.
The concavo-convex pattern 323 can be formed by means of a conventional method such as scratch and nanoimprinting in a step of forming the first cover layer 320. In an alternative example, a material or a process can be selected such that the concavo-convex pattern 323 is formed when curing the material of the first cover layer 320 itself. Such a concavo-convex pattern is spontaneously formed since rates of shrinkage of the scattering particles 321 are different from a rate of shrinkage of the first base polymer 322 which compose the first cover layer, or since shapes of the scattering particles 321 appear on the surface of the first cover layer 320 when the first cover layer 320 is formed as a thin film if a viscosity of the first base polymer 322 is low.
In the OLED display 200 according to the second embodiment, since the refractive index of the first base polymer 222 included in the first cover layer 220 is higher than the refractive index of the air, light is refracted at the interface between the first cover layer 220 and the air and therefore the output angle becomes larger. On the other hand, in the OLED display 300 according to the third embodiment, the second cover layer 330 is disposed on the first cover layer 320. Since the refractive index of the second base polymer 332 included in the second cover layer 330 is lower than the refractive index of the first base polymer 322 included in the first cover layer but higher than the refractive index of the air, the output angle of light at the interface between the first cover layer 320 and the second cover layer 330 is smaller than the output angle of  light at the interface between the first cover layer 220 of the OLED display 200 according to the second embodiment and the air. Therefore, the total reflection at the interface between the first cover layer 320 and the second cover layer 330 can be reduced, and thus the optical loss can be reduced. As a result, the OLED display 300 according to the third embodiment has an increased optical efficiency compared with conventional OLED displays.
Disposing the second cover layer 330 without forming the concavo-convex pattern on the surface of the first cover layer 320 may also reduce the total reflection at the interface between the first cover layer 320 and the second cover layer 330 and reduce the optical loss. As a result, the OLED display 300 has an increased optical efficiency compared with conventional OLED displays.
The second cover layer 330 can be formed by coating the second base polymer by means of a conventional method such as spin-coating, slit-coating, spray-coating, and screen-coating, and then by curing the second base polymer by means of a conventional method such as thermal curing and UV curing similarly to the first cover layer 320.
Fig. 7 shows a plot of a simulation result of the relationship between the diffusivity of light due to the scattering particles in the first cover layer and the concavo-convex pattern on the surface of the first cover layer and blur of an image obtained by the OLED display. As discussed above, scattering of light by the scattering particles and the concavo-convex pattern on the surface increases the optical efficiency of the OLED display. However, as shown in Fig. 7, as the diffusivity becomes larger, the blur of the obtained image becomes larger. Larger blur of an image leads to a degradation of image quality. The diffusivity is determined, for example, by changing the concentration of the scattering particles in the first cover layer. Since the concentration of the scattering particles is low, the diffusivity is small and therefore the effect of increasing the optical efficiency is small. However, since a high concentration of the scattering particles leads to aggregation of the scattering particles, problems such as degradation of scattering effect and image quality may occur. Therefore, in an OLED display, a concentration of scattering particles in a first cover layer and a concavo-convex pattern on a surface of a first cover layer have to be determined in order that both quality of an obtained image and optical efficiency fall within a preferred range.
It should be noted that the foregoing embodiments are merely intended for describing technical solutions of the present invention rather than limiting the present invention. Although the present invention is described in detail with reference to the  foregoing embodiments, those skilled in the art should understand that they may still make modifications to the technical solutions recorded in the foregoing embodiments or make equivalent replacements to a part or all of the technical features thereof.

Claims (7)

  1. An organic light emitting display having an on-cell configuration, comprising:
    an organic light emitting diode cell； and
    a first cover layer disposed on the organic light emitting diode cell, the first cover layer comprising a first base polymer and scattering particles dispersed in the first base polymer,
    wherein the organic light emitting diode cell comprises:
    a first substrate；
    a first electrode layer disposed on the first substrate；
    an organic light emitting layer disposed on the first electrode layer；
    a second electrode layer disposed on the organic light emitting layer； and
    a second substrate disposed on the second electrode layer,
    wherein the first cover layer is disposed on the second substrate,
    wherein a refractive index of the first base polymer is higher than a refractive index of a material of the second substrate, and
    wherein a refractive index of a material of the scattering particles is higher than the refractive index of the first base polymer.
  2. The organic light emitting display according to Claim 1, wherein a surface of the first cover layer opposing a surface in contact with the second substrate is concavo-convex.
  3. The organic light emitting display according to Claim 1 or 2, further comprising a second cover layer disposed on a surface of the first cover layer opposing a surface in contact with the second substrate, the second cover layer comprising a second base polymer,
    wherein a refractive index of the second base polymer is lower than the refractive index of the first base polymer.
  4. The organic light emitting display according to Claim 3, wherein a surface of the second cover layer opposing a surface in contact with the first cover layer is concavo-convex.
  5. A method of manufacturing an organic light emitting display having an on-cell configuration, comprising:
    providing an organic light emitting diode cell including: a first substrate； a first electrode layer disposed on the first substrate； an organic light emitting layer disposed on the first electrode layer； a second electrode layer disposed on the organic light emitting layer； and a second substrate disposed on the second electrode layer；
    coating a first base polymer on the second substrate, the first base polymer including scattering particles； and
    curing the first base polymer to form a first cover layer,
    wherein a refractive index of the first base polymer is higher than a refractive index of a material of the second substrate, and
    wherein a refractive index of a material of the scattering particles is higher than the refractive index of the first base polymer.
  6. The method according to Claim 5, wherein a concavo-convex pattern is formed on a surface of the first cover layer in the step of curing the first base polymer to form the first cover layer.
  7. The method according to Claim 5 or 6, further comprising:
    coating a second base polymer on the first cover layer； and
    curing the second base polymer to form a second cover layer,
    wherein a refractive index of the second base polymer is lower than the refractive index of the first base polymer.
PCT/CN2016/090770 2016-07-20 2016-07-20 An organic light emitting display and a method for manufacturing an organic light emitting display WO2018014271A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201680087739.8A CN109844975A (en) 2016-07-20 2016-07-20 Organic light emitting display and method for manufacturing organic light emitting display
PCT/CN2016/090770 WO2018014271A1 (en) 2016-07-20 2016-07-20 An organic light emitting display and a method for manufacturing an organic light emitting display

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2016/090770 WO2018014271A1 (en) 2016-07-20 2016-07-20 An organic light emitting display and a method for manufacturing an organic light emitting display

Publications (1)

Publication Number Publication Date
WO2018014271A1 true WO2018014271A1 (en) 2018-01-25

Family

ID=60992751

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2016/090770 WO2018014271A1 (en) 2016-07-20 2016-07-20 An organic light emitting display and a method for manufacturing an organic light emitting display

Country Status (2)

Country Link
CN (1) CN109844975A (en)
WO (1) WO2018014271A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112310314A (en) * 2020-10-27 2021-02-02 广东聚华印刷显示技术有限公司 Light extraction module, organic light emitting diode and display device

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090115970A1 (en) * 2007-11-02 2009-05-07 Jabil Circuit, Inc. High efficiency compact oled microdisplay projection engine
US20100155757A1 (en) * 2008-12-23 2010-06-24 Samsung Mobile Display Co., Ltd. Organic light emitting diode display
CN103715372A (en) * 2013-12-26 2014-04-09 京东方科技集团股份有限公司 Oled display panel and manufacturing method thereof
CN103824960A (en) * 2008-02-27 2014-05-28 皇家飞利浦电子股份有限公司 Hidden organic optoelectronic devices with a light scattering layer
US20150123917A1 (en) * 2013-11-05 2015-05-07 Innolux Corporation Touch display device

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI446018B (en) * 2011-12-20 2014-07-21 Au Optronics Corp Light extraction film and light emitting device using the same
EP2983018A4 (en) * 2013-04-05 2016-04-20 Mitsubishi Rayon Co Optical film and surface light emitting body
CN105098097B (en) * 2015-09-11 2017-06-06 四川虹视显示技术有限公司 The encapsulating structure and method for packing of a kind of flexible OLED devices
CN105226198A (en) * 2015-10-13 2016-01-06 京东方科技集团股份有限公司 A kind of waterproof transmission increasing flexible OLED devices device and preparation method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090115970A1 (en) * 2007-11-02 2009-05-07 Jabil Circuit, Inc. High efficiency compact oled microdisplay projection engine
CN103824960A (en) * 2008-02-27 2014-05-28 皇家飞利浦电子股份有限公司 Hidden organic optoelectronic devices with a light scattering layer
US20100155757A1 (en) * 2008-12-23 2010-06-24 Samsung Mobile Display Co., Ltd. Organic light emitting diode display
US20150123917A1 (en) * 2013-11-05 2015-05-07 Innolux Corporation Touch display device
CN103715372A (en) * 2013-12-26 2014-04-09 京东方科技集团股份有限公司 Oled display panel and manufacturing method thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112310314A (en) * 2020-10-27 2021-02-02 广东聚华印刷显示技术有限公司 Light extraction module, organic light emitting diode and display device

Also Published As

Publication number Publication date
CN109844975A (en) 2019-06-04

Similar Documents

Publication Publication Date Title
US9018620B2 (en) Organic electroluminescent light emitting device and method for manufacturing the same
US10705378B2 (en) EL element, EL element substrate, lighting device, display device, and liquid crystal display device
US8461576B2 (en) Organic light-emitting diode and light source device including same
KR20080010458A (en) Electroluminescence light source
TWI495175B (en) Organic light electroluminescent device
US10741784B2 (en) Patterned organic light emitting diode (OLED) with enhanced light extraction
US10651415B2 (en) Organic EL (electroluminescent) device
US10811396B2 (en) Display device
WO2016165364A1 (en) Organic light-emitting display device and manufacturing method therefor
WO2021258849A1 (en) Display panel and display device
TW201306342A (en) OLED lighting element and manufacture method and lighting device utilizing thereof
CN113136149B (en) Protective film for brightness uniformity of display device and display device comprising same
JP2013206883A (en) Plurality of optical management texture
US8928024B2 (en) Optical device and method for manufacturing the same
TWI570965B (en) Illumination device and display having the illumination device
WO2018014271A1 (en) An organic light emitting display and a method for manufacturing an organic light emitting display
JP2015176735A (en) El element, lighting device, display device and liquid crystal device
US20170276838A1 (en) Antireflection member
CN112289953B (en) Display panel and display device
JP2004127560A (en) Organic electroluminescent display device
CN111799387B (en) Display panel, manufacturing method thereof and display device
KR100773935B1 (en) Organic light emitting diode panel
Shin et al. Enhancing the optical performance of organic light-emitting diodes using nanoscale random rubbed structure
US20220399477A1 (en) Micro light-emitting diode device structure
JP2015176734A (en) Board for el element, el element, lighting device, display device and liquid crystal display device

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16909199

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 16909199

Country of ref document: EP

Kind code of ref document: A1