CN114303184A - Display screen and terminal equipment - Google Patents

Display screen and terminal equipment Download PDF

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Publication number
CN114303184A
CN114303184A CN201980099744.4A CN201980099744A CN114303184A CN 114303184 A CN114303184 A CN 114303184A CN 201980099744 A CN201980099744 A CN 201980099744A CN 114303184 A CN114303184 A CN 114303184A
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Prior art keywords
layer
adhesive layer
cathode
thickness
adhesive
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Chinese (zh)
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鬼岛靖典
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Huawei Technologies Co Ltd
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Huawei Technologies Co Ltd
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K77/00—Constructional details of devices covered by this subclass and not covered by groups H10K10/80, H10K30/80, H10K50/80 or H10K59/80
    • H10K77/10—Substrates, e.g. flexible substrates
    • H10K77/111—Flexible substrates
    • 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
    • H10K59/87—Passivation; Containers; Encapsulations
    • H10K59/873—Encapsulations
    • H10K59/8731—Encapsulations multilayered coatings having a repetitive structure, e.g. having multiple organic-inorganic bilayers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • 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
    • H10K2102/311—Flexible OLED
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/549—Organic PV cells

Abstract

A display screen and a terminal device capable of enhancing flexibility and foldability are provided. The display screen comprises a matrix of pixels, each pixel comprising three sub-pixels. Each sub-pixel comprises a cathode layer and a polarizer layer. The polarizer layer includes an adhesive layer. An adhesive layer is formed on the cathode layer, and H in the adhesive layer is controlled at 85 deg.C/85% RH2O and/or O2Has a permeability of 40 μm/h or less. In an embodiment, an inorganic compound barrier layer having a thickness of 1 μm or less may be formed between the cathode layer and the adhesive layer. The adhesive layer has a thickness of 100 μm or less.

Description

Display screen and terminal equipment
Technical Field
The present invention relates to a display panel and a terminal device, and more particularly to an encapsulation technique for a display device having an organic light emitting layer.
Background
The above-mentioned encapsulation technique is called Thin Film Encapsulation (TFE). TFE by alternately laminating inorganic compound barriers(hereinafter, referred to as "inorganic barrier layer") and an organic compound barrier layer (hereinafter, referred to as "organic barrier layer") to realize an encapsulation function. A structure that realizes an encapsulation function by laminating inorganic layers is also known. An organic EL display device using an Organic Light Emitting Diode (OLED) includes a TFE layer to suppress oxygen (O)2) And moisture (H)2O) intrusion into the display device.
However, the TFE layer limits the flexibility and foldability of the panel of the display device, since the laminate structure in TFE requires a certain thickness. Although recent display devices have increased demands for flexibility and foldability, display devices using a TFE layer have been generally difficult to satisfy such demands.
Disclosure of Invention
An object of the present disclosure is to provide a display screen capable of enhancing flexibility and foldability and a terminal device including the same.
A first aspect provides a display screen comprising a matrix of pixels, each pixel comprising three sub-pixels. In particular, each sub-pixel comprises a cathode layer and a polarizer layer. The polarizer layer includes an adhesive layer. An adhesive layer is formed on the cathode layer, and H in the adhesive layer is controlled at 85 ℃/85% RH2O and/or O2Has a permeability of 40 μm/h or less.
According to this aspect, the adhesive layer may perform an encapsulation function such that the adhesive layer formed on the cathode layer performs encapsulation. Therefore, the layer for encapsulation can be made relatively thin compared to the laminate structure of TFE. In addition, defects due to dust or the like generated in the CVD process can be reduced, thereby ensuring improved reliability of the display device in long-term use.
In addition, the adhesive layer has H content at 85 deg.C/85% RH2O and/or O2Has a permeability of 40 μm/h or less, and thus a display device having a practically required barrier property is configured.
According to an embodiment of the first aspect, an inorganic compound barrier layer having a thickness of 1 μm or less is formed between the cathode layer and the adhesive layer.
According to this embodiment, an inorganic compound barrier layer having a thickness of 1 μm or less is formed between the cathode layer and the adhesive layer. The display panel having the inorganic compound with a thickness of 1 μm or less can prevent H in the manufacturing process2O and O2The invasion of (2). Therefore, it is possible to prevent H in the atmosphere from being generated during the manufacturing process2O and O2Resulting in a degradation of quality.
According to an embodiment of the first aspect, the above-mentioned binder layer is formed directly on the cathode layer.
According to this embodiment, since the lamination structure of TFE is not formed on the cathode layer, the encapsulation layer can be made relatively thin.
According to an embodiment of the first aspect, the thickness of the adhesive layer is 100 μm or less.
According to this embodiment, long-term stability of the characteristics of the display device is achieved.
According to an embodiment of the first aspect, the thickness of the adhesive layer is 50 μm or less.
According to this embodiment, H is removed from the inside of the adhesive layer due to the thinner thickness of the adhesive layer2O and O2The smaller the difficulty, the more the growth rate of the dark spot area is reduced and the number of dark spots is reduced.
According to an embodiment of the first aspect, the thickness of the adhesive layer is 10 μm or less.
According to this embodiment, H is removed from the inside of the adhesive layer due to the thinner thickness of the adhesive layer2O and O2The smaller the difficulty, the more prominent the reduction in the growth rate of the dark spot area and the reduction in the number of dark spots.
According to an embodiment of the first aspect, the thickness of the adhesive layer is 5 μm or less.
According to this embodiment, H is removed from the inside of the adhesive layer due to the thinner thickness of the adhesive layer2O and O2The smaller the difficulty is, the more prominent the reduction in the growth rate of the dark spot area and the reduction in the number of dark spots become, and the thickness of the adhesive layer becomesIs desirably set to a thickness that allows absorbing irregularities (irregularities) of the substrate surface.
According to an embodiment of the first aspect, the anode layer; a light emitting unit including an organic light emitting layer formed on the anode layer; and an encapsulation member covering at least a part of the side surfaces of the anode layer, the light emitting cell, and the cathode layer.
According to this embodiment, providing the encapsulating member covering at least a part of the side surfaces of the anode layer, the light emitting cell, and the cathode layer can prevent H2O and O2From the side of the layer structure of the display device.
According to an embodiment of the first aspect, the display device is a top-emission type display device.
According to this aspect, in the top emission structure in which light is extracted from the top of the substrate (cathode layer side), the advantage of the adhesive layer having the encapsulation function can be utilized.
According to an embodiment of the first aspect, the cathode layer is a metal having a thickness of 30nm or less.
According to this aspect, setting the thickness of the metal cathode layer of Mg — Ag or the like to 30nm or less can adjust and improve the intensity of the emission spectrum in the cavity (cavity) structure. Further, an appropriate device with good balance can be arranged without significantly deteriorating the effect of extracting light to the outside due to the light absorbed by the cathode layer.
A second aspect provides a terminal device comprising a display and a processor. A display screen according to the first aspect and a processor for controlling the display screen.
According to this aspect, since the adhesive layer is formed on the cathode layer in the display screen, the layer for encapsulation can be made relatively thin as compared with the laminated structure of TFE for encapsulation. This allows for a higher flexibility and foldability of the terminal device. Further, since the laminated structure of TFE is not formed on the cathode layer, the processing time for manufacturing the terminal device can be shortened. In addition, defects due to dust and the like generated in the CVD process can be reduced, thereby improving the process yield and ensuring improved reliability of the terminal device in long-term use.
A third aspect provides a method of manufacturing a display screen comprising a matrix of pixels. Each pixel comprises three sub-pixels. The method comprises the following steps:
forming a cathode layer, and
forming a polarizer layer including an adhesive layer, wherein the adhesive layer is formed on the cathode layer, and H in the adhesive layer is at 85 ℃/85% RH2O and/or O2Has a permeability of 40 μm/h or less.
According to this aspect, the adhesive layer may perform an encapsulation function such that the adhesive layer formed on the cathode layer performs encapsulation. Therefore, the layer for encapsulation can be made relatively thin compared to the laminate structure of TFE for encapsulation. In addition, a lamination structure in which TFE is not formed for encapsulation on the cathode layer can shorten the process time for manufacturing the display device. In particular, the CVD process requires a long time, and thus the elimination of the CVD process can shorten the processing time for manufacturing the display device. The reliability of the display device can also be improved. In addition, defects due to dust and the like generated in the CVD process can be reduced, thereby improving process yield and ensuring improved reliability of the display device in long-term use.
In addition, the adhesive layer has H content at 85 deg.C/85% RH2O and/or O2Has a permeability of 40 μm/h or less, and thus a display device having a practically required barrier property is configured.
According to an embodiment of the third aspect, the method further comprises:
an inorganic compound barrier layer having a thickness of 1 μm or less is formed on the cathode layer before the adhesive layer is formed.
According to this embodiment, the inorganic compound barrier layer having a thickness of 1 μm or less is formed between the cathode layer and the adhesive layer, so that it is possible to prevent H in the atmosphere from being generated during the manufacturing process2O and O2Resulting in a degradation of quality.
According to an embodiment of the third aspect, the adhesive layer is formed directly on the cathode layer.
According to this embodiment, since the lamination structure of TFE is not formed on the cathode layer, the encapsulation layer can be made relatively thin.
According to an embodiment of the third aspect, the thickness of the adhesive layer is 100 μm or less.
According to this embodiment, long-term stability of the characteristics of the display device is achieved.
According to an embodiment of the third aspect, the thickness of the adhesive layer is 50 μm or less.
According to this embodiment, H is removed from the inside of the adhesive layer due to the thinner thickness of the adhesive layer2O and O2The smaller the difficulty, the more the growth rate of the dark spot area is reduced and the number of dark spots is reduced.
According to an embodiment of the third aspect, the thickness of the adhesive layer is 10 μm or less.
According to this embodiment, H is removed from the inside of the adhesive layer due to the thinner thickness of the adhesive layer2O and O2The smaller the difficulty, the more prominent the reduction in the growth rate of the dark spot area and the reduction in the number of dark spots.
According to an embodiment of the third aspect, the thickness of the above adhesive layer is 5 μm or less.
According to this embodiment, H is removed from the inside of the adhesive layer due to the thinner thickness of the adhesive layer2O and O2The smaller the difficulty is, the more prominent the reduction in the growth rate of the dark spot area and the reduction in the number of dark spots becomes, and the thickness of the adhesive layer is set to a thickness that allows absorbing irregularities of the substrate surface as needed.
According to an embodiment of the third aspect, the method further comprises:
providing an anode layer;
providing a light emitting unit including an organic light emitting layer formed on an anode layer; and
an encapsulation member is provided, which covers the anode layer, the light emitting cell, and at least a portion of the side surface of the cathode layer.
According to this embodimentThe encapsulation member for covering at least a portion of the side surfaces of the anode layer, the light emitting cell, and the cathode layer can prevent H2O and/or O2From the side of the layer structure of the display device.
According to an embodiment of the third aspect, the display device is a top emission type display device.
According to this aspect, in the top emission structure in which light is extracted from the top of the substrate (cathode layer side), the advantage of the adhesive layer having the encapsulation function can be utilized.
According to an embodiment of the third aspect, the cathode layer is a metal having a thickness of 30nm or less.
According to this aspect, setting the thickness of the metal cathode layer of Mg — Ag or the like to 30nm or less enables adjustment and improvement of the intensity of the emission spectrum in the cavity structure. Further, an appropriate device with good balance can be arranged without significantly deteriorating the effect of extracting light to the outside due to the light absorbed by the cathode layer.
A fourth aspect provides a method of manufacturing a terminal device, comprising:
preparing a display screen according to the first aspect; and
a processor is provided for controlling the display screen.
According to this aspect, the adhesive layer is formed on the cathode layer in each display device formed in a matrix form on the substrate, so that the encapsulation layer can be made relatively thin. This allows for a higher flexibility and foldability of the terminal device. Further, since the laminated structure of TFE is not formed on the cathode layer, the processing time for manufacturing the terminal device can be shortened. In addition, defects due to dust and the like generated in the CVD process can be reduced, thereby improving the process yield and ensuring improved reliability of the terminal device in long-term use.
Drawings
Fig. 1 is a diagram showing a structure of a display device according to an embodiment.
Fig. 2 is a view showing the structure of an adhesive layer.
Fig. 3 is a diagram showing a structure of a conventional display device as a comparative example.
Fig. 4 is a flowchart showing a manufacturing process of a display device according to a comparative example.
Fig. 5 is a view showing a manufacturing process of a display device according to a comparative example.
Fig. 6 is a flowchart showing a manufacturing process of a display device according to an embodiment.
Fig. 7 is a view showing a procedure of an adhesive layer bonding process according to an embodiment.
Fig. 8 is a diagram showing an example of the adhesive layer bonding process.
[ FIG. 9]]FIG. 9 (a) is a view showing a conventional OLED structure, and FIG. 9 (b) is a view showing H2O and O2Diagram of the mechanism of intrusion into the OLED structure.
[ FIG. 10 ]]FIG. 10 is a diagram showing H according to the embodiment2O and O2Diagram of the mechanism of intrusion into the partial structure of an OLED.
[ FIG. 11 ]]FIG. 11 is a diagram showing H according to the embodiment2O and O2Diagram of the mechanism of intrusion into the partial structure of an OLED.
Fig. 12 is a graph showing the relationship between time and permeability in a part of the OLED structure.
Fig. 13 is a graph showing the angular dependence of electroluminescence intensity.
Fig. 14 is a diagram showing a relationship between a storage time and a dark spot area in a reliability test.
Fig. 15 is a diagram showing a relationship between a storage time and a shrinkage area in a reliability test.
Fig. 16 is a diagram showing an example of a dam (dam) structure of an OLED.
Fig. 17 is a diagram showing a relationship between a storage time and the number of dark spots in a reliability test.
Fig. 18 is a diagram showing a relationship between a storage time and the number of dark spots in a reliability test.
Fig. 19 is a diagram showing the configuration of a display screen equipped with a display device according to the present embodiment.
Detailed Description
Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The display screen according to the embodiment can be applied to, for example, a terminal device. The terminal device may be a smartphone. The terminal may include a display screen and a processor, such as a Central Processing Unit (CPU), for controlling the display screen.
(first embodiment)
Next, with reference to fig. 1, a structure of a display device according to a first embodiment of the present invention is described. The display device 100 is used in a display screen, which will be described later with reference to fig. 19, and functions as a display screen of a smartphone. Fig. 1 shows a cross section of a display device 100, the top side of which is the side of the display seen by a user, and fig. 1 shows a part of the display device 100 to show the layer structure thereof.
The display device 100 is configured as a layer structure including a rear barrier layer 411, a back plate 412, a front plane 413, and a polarizer layer 801.
Back side barrier 411 for preventing O2And H2O intrudes from the back surface, and is configured to have a first inorganic barrier layer 401a (silicon nitride (SiN))x) Silicon oxynitride (SiN)xOy) Silicon oxide (SiO)x) Etc.), an organic barrier layer 401b (organic resin), and a second inorganic barrier layer 401c (SiN)xOr SiOx)。
The backplane 412 has drivers of Thin Film Transistors (TFTs) embedded directly under the respective pixels to apply voltages or currents to selected pixels to individually operate the pixels. The back plate 412 has a substrate 402a and a layer (PLN/TFT)402b including a TFT and a planarization film, which are sequentially stacked.
The front plane 413 is configured to include an anode layer (hereinafter, referred to as an "anode") 403a, a light emitting cell 415, and a cathode layer (hereinafter, referred to as a "cathode") 403 g. The light emitting unit 415 includes a Hole Injection Layer (HIL) 403b, a Hole Transport Layer (HTL) 403c, an organic light emitting layer 403d, a Hole Blocking Layer (HBL) 403e, and an Electron Transport Layer (ETL) 403f, which are sequentially laminated from the anode 403a side.
The polarizer layer 801 is configured to have sequential lamination of a first adhesive layer 801a (including an adhesive and an inorganic barrier layer), a polarizing Plate (POL)405b, and a second adhesive layer 405c (including an adhesive). Note that the first adhesive layer 801a may also include a layer of a Touch Panel (TP). The adhesive of the first adhesive layer according to the present embodiment may be configured as, for example, an Optically Clear Adhesive (OCA). The adhesive of the second adhesive layer 405c used may be the same as the first adhesive. In addition, a thermosetting adhesive (e.g., an acrylic adhesive, an epoxy adhesive, a urethane adhesive, a silicone adhesive, or a cyanoacrylate adhesive) and an ultraviolet curing adhesive, which have different components from those of the first adhesive, may be used. In an embodiment, the first adhesive layer 801a may be formed directly on the cathode 403 g.
Fig. 2 is a view showing a detailed structure of the first adhesive layer 801 a. As shown in (a) of fig. 2, the first adhesive layer 801a may be configured to include only the adhesive layer 201. Alternatively, as shown in fig. 2 (b), the adhesive layer 201 may be stacked on SiNx、SiNxOy、SiOxEtc., or, as shown in fig. 2 (c), the above-described adhesive layer 201 and inorganic barrier layer 202 may be stacked in the reverse order to that shown in fig. 2 (b). Further, the first adhesive layer 801a may be configured to include a Touch Panel (TP). In this case, the adhesive layer 201, the TP 203, and the inorganic barrier layer 202 may be sequentially stacked from the bottom as shown in fig. 2 (d), or, as shown in fig. 2 (e), the above-described adhesive layer 201, TP 203, and inorganic barrier layer 202 may be stacked in the reverse order to that shown in fig. 2 (d).
Furthermore, the inorganic barrier layer 202 may be formed of multiple layers of SiNx、SiNxOyOr SiOxAnd (4) forming. Further, one adhesive layer, TP 203, and another adhesive layer may be sequentially stacked on the inorganic barrier layer 202.
The display assembly 100 is a top emission type display device that extracts light generated when holes injected from the anode 403a and electrons injected from the cathode 403g are recombined in the organic light emitting layer 403d from the cathode 403g side opposite to the substrate 402 a.
The substrate 402a is a support in which a plurality of display modules 100 are placed and formed on one main surface side of the support; for example, the substrate 402a is made of quartz, glass, metal foil, a film or sheet made of resin, or the like. Of these materials, quartz and glass are preferable. When the substrate 402a is made of resin, polyester, such as polybutylene naphthalate (PBN), methacrylic resin represented by polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), Polyimide (PI), Polyamide (PA), polycarbonate resin, or the like, may be used as a material of the substrate 402 a.
In order to efficiently inject holes into the light emitting unit, the anode 403a is preferably made of an electrode material having a large work function at a vacuum level, for example. Specifically, a simple substance of a metal element such as chromium (Cr), gold (Au), platinum (Pt), nickel (Ni), copper (Cu), tungsten (W), or silver (Ag), or an alloy thereof can be used as such an electrode material. In addition, the anode 403a may have a laminated structure of a metal film made of a simple substance or an alloy of such a metal element and a transparent conductive film made of Indium Tin Oxide (ITO), indium zinc oxide (InZnO), or an alloy of zinc oxide (ZnO) and aluminum (Al) or the like.
In particular, in the case of a top emission type display device, an electrode having a high reflectance is used as the anode 403a, whereby the efficiency of extracting light to the outside is improved due to an interference effect and a high reflectance effect. For example, the anode 403a preferably uses a laminated structure of a first layer excellent in light reflection property and a second layer provided on a portion of the first layer near the HIL 403b and having light transmittance and a large work function. The first layer is preferably made of an alloy that mainly contains Al as a main component and also contains, as an auxiliary component, an element having a work function relatively smaller than that of Al as the main component. Any of the lanthanides is preferably used as such an auxiliary component. Although any of lanthanides has a small work function, when these elements are contained in the auxiliary component, any of these elements can improve the stability of the anode and satisfy the hole injection property of the anode. An element such as silicon (Si) or copper (Cu) may be used as an auxiliary component of the first layer in addition to any lanthanoid element.
The second layer may be made of an oxide of aluminum alloy, an oxide of molybdenum (Mo), an oxide of zirconium (Zr), an oxide of chromium (Cr), or an oxide of tantalum (Ta). For example, when the second layer is composed of an oxide layer (including a natural oxide film) of an aluminum alloy containing any of lanthanoids as an auxiliary component, since any of the oxides of lanthanoids has a high transmittance, the transmittance of the second layer containing any of the oxides of lanthanoids as an auxiliary component is excellent. Thus, the surface of the first layer maintains a high reflectivity. Further, using a transparent conductive layer made of ITO or the like in the second layer improves the electron injection property of the anode 403 a. It is to be noted that since ITO or the like has a large work function, the use of ITO or the like in the side contacting the substrate 402a, i.e., in the first layer, can enhance carrier injection efficiency and can also enhance adhesion between the anode 403a and the substrate 402 a.
It is to be noted that when the method for driving a display panel including a plurality of display devices 100 is an active matrix system, each pixel portion is patterned with a pixel definition layer (PDL, WIN) and is provided to be connected to a TFT for driving after the anode 403a is formed.
The HIL 403b, the HTL403c, the organic light emitting layer 403d, the HBL 403e, and the ETL403f included in the light emitting unit 415 are organic layers. These organic layers are composed of materials to be described later, in addition to an acrylic compound and Hexamethyldisiloxane (HMDSO). The organic layer is formed by, for example, an inkjet printer or the like. The surface of the ETL403f opposite to the HBL 403e is covered with a cathode 403 g. Although there are no particular limitations on the thickness, constituent material, and the like of each layer constituting the organic layer, some examples thereof will be described below.
The HIL 403b is a buffer layer for improving efficiency of hole injection into the organic light emitting layer 403d and preventing generation of leakage current. The thickness of the HIL 403b is preferably set in the range of 5 to 200nm, more preferably, in the range of 8 to 150 nm. The material for the HIL 403b may be sufficiently selected relative to the materials for the electrodes and adjacent layers. Examples of the above-mentioned material include, for example, polyaniline and a derivative thereof, polythiophene and a derivative thereof, polypyrrole and a derivative thereof, polyphenylenevinylene and a derivative thereof, polythienylenevinylene and a derivative thereof, polyquinoline and a derivative thereof, polyquinoxaline and a derivative thereof, a conductive high molecular material (for example, a polymer containing an aromatic amine structure in a main chain or a side chain thereof), metal phthalocyanine (for example, copper phthalocyanine), and carbon. Specific examples of the conductive polymer material include oligoaniline and polydioxythiophene such as poly (3,4-ethylenedioxythiophene) (PEDOT).
The HTL403c serves to enhance the efficiency of hole transport to the organic light emitting layer 403 d. The thickness of the HTL403c, which depends on the overall structure of the device, is preferably set in the range of, for example, 5 to 200nm, more preferably, 8 to 150 nm. A light emitting material soluble in an organic solvent (for example, polyvinylcarbazole and derivatives thereof, polyfluorene and derivatives thereof, polyaniline and derivatives thereof, polysilane and derivatives thereof, polysiloxane derivatives having aromatic amine in a side chain or a main chain, polythiophene and derivatives thereof, polypyrrole, triphenylamine derivatives, and the like) can be used as the material of the HTL403 c.
In the organic light emitting layer 403d, application of an electric field causes recombination of electrons and holes to emit light. The thickness of the organic light emitting layer 403d depending on the entire structure of the device is preferably set in the range of, for example, 10 to 200nm, more preferably, 20 to 150 nm. The organic light emitting layer 403d may have a single layer structure or a laminated structure.
The material for the organic light emitting layer 403d should be selected according to the corresponding emission color; for example, materials that can be used for the organic light-emitting layer 403d include (poly) p-phenylene vinylene derivatives, polyfluorene polymer derivatives, polyphenyl derivatives, polyvinylcarbazole derivatives, polythiophene derivatives, pyrene pigments, coumarin pigments, rhodamine pigments, triphenylamine derivatives, and materials obtained by doping the above-described polymer materials with organic EL materials. For example, as the dopant, red fluorene, perylene, 9, 10-diphenylanthracene, tetraphenylbutadiene, nile red, coumarin 6, a triphenylamine derivative, or the like can be used. Note that the material for the organic light-emitting layer 403d can be obtained by mixing two or more of the above-described materials. In addition, the material for the organic light emitting layer 403d is not limited to the above-described high molecular material, and may be a combination of low molecular materials. Examples of such low-molecular materials include anthracene, benzene, styrylamine, triphenylamine, porphyrin, triphenylene, azaphenylene, tetracyanoquinodimethane, triazole, imidazole, oxadiazole, polyarylalkane, phenylenediamine, arylamine, oxazole, fluorenone, hydrazone, stilbene, triphenylamine derivatives of the above materials, and heterocyclic conjugated monomers or oligomers of polysilane compounds, vinylcarbazole compounds, thiophene compounds, aniline compounds, and the like.
In addition to the above materials, as a material of the organic light-emitting layer 403d, a material having high light-emitting efficiency as a light-emitting guest material, for example, an organic light-emitting material (for example, a low-molecular fluorescent material, a phosphorescent pigment, a metal complex, or the like) can be used.
Note that the organic light emitting layer 403d may be, for example, an organic light emitting layer having a hole transporting property and serving as an HTL403c, and an organic light emitting layer having an electron transporting property and serving as an ETL403f to be described later.
HBL 403e serves to inhibit the flow of holes into cathode 403g, and may be made of, for example, BCP (2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline). The thickness of the HBL 403e may be set in the range of, for example, 0.1 to 100 nm.
The ETL403f serves to enhance efficiency of electron transport to the organic light emitting layer 403 d. The thickness of the ETL403f, which depends on the overall structure of the device, is preferably set in the range of, for example, 5 to 200nm, more preferably in the range of 10 to 180 nm.
As the material of the ETL403f, an organic material having excellent electron transport ability is preferably used. Enhancing the efficiency of transporting electrons to the organic light emitting layer 403d suppresses the change in emission color due to the electric field intensity, which will be described later. Specifically, for example, an arylpyridine derivative, a benzimidazole derivative, or the like is preferably used. Therefore, even at a low driving voltage, high electron supply efficiency can be maintained. Other examples of such organic materials include: alkali metals and oxides thereof, composite oxides thereof, fluorides thereof, and carbonates thereof, alkaline earth metals and oxides thereof, composite oxides thereof, fluorides thereof, and carbonates thereof, and rare earth metals and oxides thereof, composite oxides thereof, fluorides thereof, and carbonates thereof.
ETL403f has electron donor properties; for example, an electron transport material doped with an n-type dopant (specifically, the material described above for the ETL403 f) may be used as the material of the ETL403 f. Examples of the n-type doping material include alkali metals or oxides thereof, composite oxides thereof, fluorides thereof, and organic complexes thereof, and alkaline earth metals or oxides thereof, composite oxides thereof, fluorides thereof, and organic complexes thereof.
In particular, when the electron mobility of the ETL403f is relatively large, a material having low electronegativity and excellent electron donor properties may be used. Among these materials, a material having small light absorption in the visible light region in a thin film state is preferable. Specifically, a metal material having a low electron affinity (for example, alkali metals such as lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs), alkaline earth metals such as beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra), or lanthanoid metals such as samarium (Sm), ytterbium (Yb), gallium (Ga), and lanthanum (La)) is an example of such a material.
For example, the cathode 403g is made of a material having a thickness of about 10nm, excellent light transmittance, and a small work function. In addition, light extraction can be ensured even if an oxide is used to form the transparent conductive film. In this case, ZnO, ITO, InZnO, indium tin zinc oxide (InSnZnO), or the like can be used. Further, although the cathode 403g may be a single layer, the cathode 403g may also have a structure of multiple layers stacked in order from the anode 403a side.
The cathode 403g may be formed of a mixed layer containing an organic light-emitting material (e.g., an aluminum quinoline complex, a styrylamine derivative, or a phthalocyanine derivative). In this case, the cathode 403g may further have an Al-Li layer or an Mg-Ag layer. In addition, the cathode 403g should take an optimum combination and an optimum lamination structure.
The first adhesive layer 801a of the polarizer 801 includes adhesive layers as shown in fig. 1 to 3. The adhesive layer contains, as a base material, a material selected from those given in (1) below, wherein a material selected from resins given in (2) below is added as a tackifying resin to provide adhesiveness. If there is no problem with compatibility, a variety of materials can be selected from (i) to (vi) of (1). Alternatively, the adhesive layer may contain a material selected from the following (3) as a filler.
The adhesive layer of the present embodiment obtained by selecting these materials has O obtained to penetrate into the inside of the first adhesive layer 801a2And H2The function of O. In particular, the selected materials include use as getters to obtain O2And H2And O is selected from the group consisting of. In addition, the function of the side chain of the selected material also captures O2And H2And O. The function of the single adhesive layer as described above enables it to perform the operations to be described below with reference to fig. 12 and subsequent drawings.
(1) Base material
(i) Epoxy resin
Herein, the above epoxy resin may have a glycidyl group.
(ii) A blocked isocyanate obtained by blocking an isocyanate compound with imidazole or a resin composition containing a phenoxy resin and a propoxy resin.
(iii) Styrene-isobutylene modified resins.
The styrene-isobutylene modified resin has a polystyrene main chain and a polyisobutylene bone block copolymer, which have functional groups. The functional group may include, but is not limited to, one or more of an anhydride group, an amino group, a carboxyl group, a cyanate group, an epoxy group, a hydrazide group, a hydroxyl group, an isocyanate group, an oxazoline group, an oxetane group, and a phenol group.
(iv) Modified polyolefin resin
The modified polyolefin resin includes methacrylic acid, alkyl acrylate, and acid anhydride modified polyolefin resins.
(v) Phenoxy resin of type A and/or type F
The phenoxy resin is synthesized by bisphenol A epoxy resin and/or bisphenol F epoxy resin.
(vi) Polyisoprene and/or polyisobutylene resins
The polyisoprene and/or polyisobutylene resin may have functional groups that can react with epoxy groups.
(2) Tackifying resins
The tackifying resin may include, but is not limited to, one or more of the following: alicyclic saturated hydrocarbon resins, aliphatic petroleum resins, dicyclopentadiene-modified hydrocarbon resins, alicyclic unsaturated hydrocarbon resins, and/or saturated hydrocarbon resins containing a cyclohexane ring.
(3) Filler material
Fillers may include, but are not limited to, one or more of the following: alumina, barium titanate, hydrotalcite, titanium oxide, cerium oxide, and/or zirconium oxide.
In another embodiment of the present disclosure, the first adhesive layer 801a further comprises SiNx/SiNxOy/SiOxEtc. thin inorganic barrier layers. Addition of inorganic barrier layer to prevent H2O and O2Resulting in a degradation of the OLED quality and the thickness of the inorganic barrier layer may be greater than 0nm and equal to about 1 μm or less. For example, SiN may be formed on cathode 403g by CVD before the adhesive layer is directly adhered to cathode 403gx/SiOxAnd then an adhesive layer is bonded to the inorganic barrier layer to laminate the first layer. The first layer is suitably chosen to prevent H from the ambient environment during processing2O and O2Resulting in a decrease in the quality of the lower cathode 403 g. Preferably, the first layer is thin.
In another embodiment of the present disclosure, the first adhesive layer 801a further includes a Touch Panel (TP). As the TP, polyethylene terephthalate (PET), cycloolefin polymer (COP), Polyimide (PI), Polycarbonate (PC), cellulose Triacetate (TAC), or the like, in which a wiring pattern of ITO, copper, or the like is formed, may be used. The TP is formed by a lamination process. The adhesive layer, inorganic barrier layer, and TP may be stacked in any order.
The polarizing plate 405b is used to prevent reflection of sunlight, and polyvinyl alcohol (PVA), triacetyl cellulose (TAC), or the like is used for the polarizing plate. The second adhesive layer 405c is used to adhere higher layers, such as color filters. The adhesive used herein may be an adhesive layer, or an adhesive other than an adhesive layer may be used.
Fig. 3 shows a structure of a conventional display device as a comparative example. In the display device 200, the rear barrier layer 411, the back plate 412, and the front plane 413 are the same as the rear barrier layer 411, the back plate 412, and the front plane 413 in fig. 1. The display device 200 has a TFE 414 and a polarizer 416 stacked on the cathode 403g of the front plane 413. TFE 414 has SiN about 1 μm thickx/SiOxA first inorganic barrier layer 404a, an organic barrier layer 404b having a thickness of about 7.5 μm, and SiN having a thickness of about 1 μmx/SiOxThe second inorganic barrier layer 404 c. Polarizer 416 is configured as SiN in TFE 414x/SiOxHaving a first adhesive layer 405a (including conventional adhesive, TP, and/or SiN)x/SiOx) POL 405b, and a second adhesive layer 405 c. As can be understood from comparison with the display device 100, the thickness of the TFE 414 of the display device 200 affects the thickness of the entire display device 200.
Next, a procedure of a manufacturing method of a display device according to a comparative example is described with reference to fig. 4.
First, a substrate 402a is prepared, and a back surface blocking layer 411 is formed on the back surface of the substrate 402 a. A Thin Film Transistor (TFT) and a layer (PLN/TFT)402b of a planarization film (PLN) are formed on the surface of the substrate 402 a. Next, the anode 403a, the HIL 403b, the HTL403c, the organic light emitting layer 403d, the HBL 403e, and the ETL403f are formed on the planarized PLN/TFT 402b by, for example, an inkjet printer. Then, a cathode 403g is formed on the ETL403f by, for example, vacuum evaporation (vacuum evaporation). The front plane 413 is formed in this manner (S101).
Note that an organic cover layer may be formed on the cathode 403 g. An organic capping layer is formed in the top emission type organic electroluminescent device to prevent a considerable amount of light from being lost due to total reflection of light when the cathode 403g is formed. The organic covering layer preferably contains one member selected from the group consisting of an aromatic diamine derivative, a triamine derivative, 4' -bis (carbazol-9-yl) biphenyl (CBP), and tris (8-hydroxyquinoline) aluminum (Alq 3).
Next, TFE is formed on the cathode 403 g. First, in step S102, SiN is deposited on the cathode 403g by CVD in vacuum (e.g., 1Pa or less)xThe first inorganic barrier layer 404 a. Then, in step S103, a printing technique (e.g., ink jet method) is used to print on the first SiN layerxAn acrylic resin layer is formed on the layer. Then, in step S104, the acrylic resin layer is thermally cured in dry air to form the organic barrier layer 404 b. Then, in step S105, SiN is formed by CVD in vacuumxThe second inorganic barrier layer 404 c. Then, in step S106, a first adhesive layer 405a including an adhesive layer, a polarizing Plate (POL)405b, and a second adhesive layer 405c are formed on the TFE 414 through a lamination process. Thus, the polarizer 416 is formed.
TFE formed in the above process has at least three layers of complex structure including inorganic barrier layer/organic barrier layer/inorganic barrier layer. The inorganic barrier layer/the organic barrier layer/the inorganic barrier layer are respectively 1-2 μm/6-12 μm/1-2 μm thick, which hinders the flattening of the display screen using the OLED.
Furthermore, the next generation of OLEDs can be turned to foldable OLED solutions, such as inner-folded type, outer-folded type, and S-shaped (inner and outer). The foldable OLED is preferably made of a soft material (e.g. organic molecules). In fact, in the general organic laminate structure of an OLED device, organic molecules are not chemically bonded, but form an organic thin film by intermolecular Van der Waals (Van der Waals) interactions. On the other hand, the inorganic portion of TFE (i.e., SiN)xOy、SiNx、SiOxEtc.) are rigid membranes with very strong binding forces and are therefore bendingAre fragile and fragile in handling. With respect to foldable OLEDs, it is desirable to not use such TFE materials as much as possible for improved quality and extended lifetime.
In the structure of the comparative example shown in fig. 5, the first inorganic barrier layer 404a of TFE 414 is formed in vacuum, the organic barrier layer 404b is formed in air, and the second inorganic barrier layer 404c is formed again in vacuum. This means that the device substrate enters and exits the vacuum chamber during the formation of the thin film encapsulation structure, resulting in low mass productivity. In particular, since an alloy of highly active metals (e.g., highly active Mg and Li) is used for the cathode, the cathode is oxidized when placed in air.
Likewise, SiH is used4Gas and NH3Suitable mixtures of gases, by CVD, may form SiN of good qualityxOyOr SiNx. CVD denotes chemical vapor deposition (chemical vapor deposition) in which a gas is supplied as a film-forming material and thin film deposition is performed by a chemical reaction on the surface of a substrate (base material) in a gas phase. CVD has some drawbacks in forming inorganic barrier layers. Plasma CVD and thermal CVD will be described below as examples to explain these disadvantages.
Plasma CVD is a thin film deposition technique in which a high frequency is applied to parallel plate-type electrodes in a reaction furnace, and a source gas composed of a halide of a material as a main component of a thin film and a required carrier gas such as hydrogen or nitrogen are decomposed by plasma vaporization to deposit the material on a substrate placed on one of the electrodes to form a thin film.
Plasma generation schemes include high-frequency (inductively coupled) discharge, direct-current glow discharge, and microwave discharge, in addition to high-frequency (parallel plate type) discharge. The use of plasma makes it possible to perform thin film deposition even at 300 ℃ lower than that of thermal CVD and prevent reaction with the substrate. Therefore, a thin film can be deposited on a heat-non-resistant substrate such as plastic. In addition, plasma CVD has many features such as ease of deposition over a large area and the ability to form a film of uniform thickness. The pressure at which the thin film is deposited is 1 to several hundred Pa, and plasma is easily generated at this pressure. In OLEDs, an inorganic barrier layer is typically deposited using plasma CVD.
However, SiH in plasma processing4Gas and NH3Radiant heat generated by gases, and in SiNxOyOr SiNxParticles constituting an object colliding with the surface of the cathode upon deposition of the thin film directly damage the surface of, for example, Mg — Ag alloy used for the cathode.
In thermal CVD, a source gas and an oxidizing agent or a reducing agent are mixed, and the mixture is introduced into a reaction vessel, so that a chemical reaction occurs on a high-temperature substrate surface. The chemical reaction is determined by the raw material ratio, the reaction temperature and the design of the reaction vessel. Thermal CVD has the advantages of relatively simple equipment configuration, capability of forming a high-purity film, good coverage and the like. However, thermal CVD also has disadvantages such as limitations on available film formation temperatures, available substrates, and available source gases, and the quality of the film may be degraded at low temperatures.
In CVD, the attack of energetic particles may damage the OLED when the film is heated to high temperatures during deposition. For example, thermal radiation from a target may increase the substrate temperature of an OLED, and thus a deposition thickness of 1 μm may increase the substrate temperature to about 100 ℃. Although the glass transition temperature Tg of the organic material used for the OLED is generally higher than 100 ℃ (thus not affecting the organic material), it is difficult to maintain the boundary state of the laminated structure. That is, the layers are easily mixed at the boundary portion of the laminated structure. This phenomenon causes degradation of the OLED, making it difficult to maintain an exciton confinement structure (exciton confinement structure) around the light emitting layer. This means a reduction in Internal Quantum Efficiency (IQE).
To suppress SiNxSuch damage to the OLED by thin film deposition requires suppression of the increase in the temperature of the surface of the deposited thin film. This imposes a limit to increasing the deposition rate.
In addition, during CVD, dust adheres to the CVD reaction vessel, causing dark spots, short circuits, shrinkage, and the like. This results in reduced panel yield.
Fig. 6 is a flowchart illustrating a manufacturing process of a display device according to an embodiment. In step S202 after step S101, the adhesive layer is bonded to the cathode by a lamination process. The adhesive layer may be an optically clear adhesive film OCA. The adhesion of the adhesive layer may be performed in air. Thus, pre-bonding the polarizing layer including the polarizing plate and the touch panel to the adhesive layer allows the lamination structure on the cathode to be bonded by lamination without performing heat treatment in air.
Accordingly, as shown in fig. 7, if a layer structure including the back side barrier layer 411, the back plate 412, and the front plane 413 is formed, the remaining steps may be performed through a lamination process.
Fig. 8 schematically shows the course of the lamination process. Fig. 8 (a) shows a layer structure 301 in which a polarizing plate 303 is formed on the OCA 302. On the other hand, fig. 8 (c) shows a layer structure 304, the layer structure 304 including a backside barrier layer 306, a back-plate 307, and a front plane 308. The layer structure 301 and the layer structure 304 are prepared separately, and as shown in fig. 8 (b), the two layer structures are press-bonded by a roll laminator 305.
It should be noted that during the final stages of the lamination process, an autoclave may be used to remove the remaining air from the lamination surface by heat and pressure.
Next, H in the present embodiment is described2O and/or O2Principle of penetration into display device and prevention of H2O and/or O2Reliability of penetration.
Acrylic compounds or HMDSO are often used as part of the composition of the protective film of an OLED, but this composition may trap H from the air or from the manufacturing process flow2And O. This is detrimental to the reliability of the OLED.
Providing TFE on the front plane prevents H2O penetrates from the top to the front plane. However, the layer structure of the display device has a disadvantage in that the layer structure is susceptible to H2O and O2Influence of side penetration.
FIG. 9 shows H2O and O2Penetration (intrusion) into the display device of the comparative example. Fig. 9 (b) shows the front plane 413 and the TFE 414 in the display device 200 shown in fig. 9 (a). As shown in FIG. 9 (b), H2O and O2Horizontally penetrating from the surface between layers and the side of layersAnd then falls. Therefore, when the number of layers of TFE is large and the area of the side surface of the layer is large, H2O and O2Readily penetrate into the layer.
Fig. 10 shows a layer structure according to the present embodiment. In the layer structure shown in FIG. 10, H2O and O2Can permeate from the side of the first adhesive layer 801a and the surface of the cathode 403g, but reduces the permeation path to suppress H2O and O2The penetration of (2).
Fig. 11 shows another layer structure according to the present embodiment. The layer structure shown in fig. 11 has an anode 602, an OLED 603, banks (banks) 608 separating the OLEDs 603, a cathode 604, a first adhesive layer 605, a polarizing plate 606, and a second adhesive layer 607 stacked on a back sheet 601 including a substrate and TFTs. In this case, H is suppressed2O and O2Penetration to the sides of the first adhesive layer 605 and the surface between the first adhesive layer 605 and the cathode 604.
FIG. 12 is a view showing H according to the present embodiment2O and O2Graph of permeability into the adhesive layer. In the graph, the horizontal axis represents the storage time at 85 ℃/85% RH, and the vertical axis represents the number of dark spots in H2O and O2Permeability of (d). In contrast to conventional TFE structures, directly or via SiNxAnd/or SiOxIs attached to the material of the adhesive layer on the OLED device2O and/or O2The permeation rate is low and has a low permeation rate over storage time. In addition, the permeability curve becomes a saturation curve and has a small slope as shown by the dotted line in fig. 12. With respect to the permeability saturation curve, the adhesive layer has the property that the filler added to the adhesive layer acts as a getter to capture H by chemical reaction2O and/or O2. Alternatively, the pressure-sensitive adhesive layer has a property that a side chain of a substance constituting the pressure-sensitive adhesive layer has a structure that reacts with H by a chemical reaction2O and/or O2Bound moiety to capture H by chemical reaction2O and/or O2。
The experimental results show that in order to obtain the actually required performance, the adhesive is adhered under the condition of 85 ℃/85% RHH of the material of the mixture layer2O and/or O2The permeation rate should be 0 μm/h or more and 40 μm/h or less. For 4mm2Preferably, the dark spot area after 300 hours should be 0 μm or more under the condition of 85 ℃/85% RH2And is less than or equal to 3000 μm2(i.e. the area is less than or equal to 0.75%).
FIG. 13 shows emission surfaces of display devices relating to the present embodiment and comparative example every 1cm2Angle dependence of the electroluminescence intensity (a.u.). In this example, the current flowing through the circuit is 10 mA. The display device according to the present embodiment has higher electroluminescence intensity in the range of-90 ° to 90 ° than the display device according to the comparative example. The electroluminescence intensity was used to calculate External Quantum Efficiency (EQE), which was used as an index of the characteristics of the OLED display device. That is, EQE (%) is the ratio of the number of photons extracted from the device to the number of carriers injected into the device, and this value ηEQEGiven by the following equation.
ηEQE＝k·λ/I
Where k is a constant, P is the emission intensity per unit area of the OLED, λ is the wavelength, and I is the current flowing through the display device.
Therefore, as can be understood from the figure, the EQE of the display device according to the present embodiment has been improved. This effect is dependent on the design of the display device (in particular SiN)xAnd SiNxOyDesign of thickness of (d) is obtained.
Fig. 14 shows the measurement results of the dark spot area with respect to the storage time under the condition of 85 ℃/85% RH. In the figure, example 1 is a display device having an adhesive layer with a thickness of 5 μm, the reference example is a display device having conventional TFE, and example 2 is a display device having an adhesive layer with a thickness of 20 μm. TFE Structure 800nm SiN for reference examplex300nm SiNxOyOrganic resin/200 nm SiN 8 μmxOy800nm SiNxan/OLED. According to the measurement results, the value of the dark spot area in example 1 was substantially the same as that in the reference example up to 300 hours.
In the case of example 2, the increase in the dark spot area was very fast compared to the 5 μm adhesive layer. The rate of increase of the dark spot area appears to be due to the difficulty in removing H inside the adhesive layer2O and O2Thereby, the effect is achieved. Therefore, making the adhesive layer formed on the OLED thinner can provide better characteristics. Preferably, the thickness of the adhesive layer is suitably chosen so as to retain sufficient strength for bonding and absorbing the roughness of the underlying structure, and is greater than 0nm and less than or equal to about 100 μm. In particular, when the thickness of the adhesive layer is about 50 μm or less, the growth rate of the dark spot area is significantly reduced, and when the thickness of the adhesive layer is about 10 μm or less, the suppression of the growth rate becomes more prominent. Further, setting the thickness to about 5 μm or less more significantly reduces the growth rate of the dark spot area and the number of dark spots, and the thickness is set as a thickness allowing absorption of irregularities of the substrate surface as needed.
Fig. 15 shows the measurement results of the shrinkage area with respect to the storage time under the condition of 85 ℃/85% RH. In the figure, the structures of example 1, example 2, and the reference example are the same as those of fig. 14. The measurement results showed that in the case of example 1 having an adhesive layer of 5 μm thickness, the shrinkage area was not seen before 300 hours. However, in the case of example 2 having an adhesive layer 20 μm thick, a shrinkage area was still visible at 300 hours. In the case of example 1, the constricted area occurred at a point at 900 hours. It should be noted, however, that the occurrence of the shrinkage area can be suppressed by the dam structure applied to the side of the display device.
Fig. 16 is a diagram illustrating a layer structure according to another embodiment of the present disclosure. The layer structure 1600 is formed to have a substrate 1201, a layer structure 1202 formed by laminating a multilayer TFT to a cathode formed on the substrate 1201, and an adhesive layer 1206 formed on the layer structure 1202. Then, an encapsulating member 1205 having a so-called dam structure is disposed on the side surface of the layer structure 1202 to cover the side surface. The dam structure is formed of, for example, an ultraviolet curable resin, and has a sectional shape including a plurality of irregularities as shown in fig. 16. The layer structure 1600 further includes an adhesive layer 1206, the adhesive layer 1206 being formedFor the top of the cover layer structure 1202 and the encapsulation member 1205. By using a dam structure as described above, if H2O and O2Penetration from the side of the layer structure, then H2O and O2Move along the irregular surface such that H2O and O2The distance to the side of the layer structure of the OLED is increased, so that H is suppressed2O and O2Penetrating into the layer structure 1202 and the substrate 1201.
It should be noted that the layer structure is not limited to the example shown in fig. 16, and any layer structure provided with an encapsulating member covering at least a part of the side faces of the light emitting unit and the cathode may at least partially prevent H2O and O2Permeate from the side.
Fig. 17 shows the measurement results of the number of dark spots with respect to the storage time under the condition of 85 ℃/85% RH. In the figure, the structures of example 1, example 2, and the reference example are the same as the measurement target in fig. 14. The measurement results showed that in the case of example 1 having an adhesive layer of 5 μm thickness, the number of dark spots was smaller than that in the reference example at 300 hours. Whereas for adhesive layers with a thickness of more than 10 μm the number of dark spots increases significantly after 100 hours. In view of this, H contained in the adhesive layer itself2O and O2May affect the increase in the number of dark spots.
Fig. 18 shows, on the basis of fig. 17, the results of measuring OLEDs having adhesive layers of different thicknesses. With respect to the thickness of the adhesive layer, as the adhesive layer becomes thinner, the number of dark spots may be reduced. The reduction in the number of dark spots may provide good conditions by the display device bonding the OLED display device and the adhesive layer such that there is no gap between the surfaces thereof. Therefore, the reduction in the number of dark spots is limited by the adhesion of the adhesive layer. The adhesion depends on the design of the wiring on the substrate in the back sheet, the condition of the wiring, and the like. Since the OLEDs are formed on the PLN/TFT of the backplane, the overall surface roughness depends on the design of the device, and the minimum thickness of the adhesive layer is determined according to these conditions. In order to maintain long-term stability at 85 ℃/85% RH, the thickness of the adhesive layer is preferably greater than 0nm, less than or equal to 100 μm. In particular, when the thickness of the adhesive layer is about 50 μm or less, the number of dark spot areas is significantly reduced, and when the thickness of the adhesive layer is about 10 μm or less, the suppression of the number of dark spot areas becomes more prominent. Further, setting the thickness to about 5 μm or less more significantly reduces the growth rate of the dark spot area and the number of dark spots, and the thickness is set as a thickness allowing absorption of irregularities of the substrate surface as needed.
Fig. 19 shows a configuration of a display screen 1800 including the display device 100 of the present embodiment. The display screen 1800 serves as a display for a terminal device (e.g., a smartphone, etc.) and is controlled by the processor. For example, the display screen 1800 has a pixel matrix including a plurality of display devices 100. Each pixel 1802 includes light emitting devices corresponding to three sub-pixels (for example, a red light emitting device 100R, a green light emitting device 100G, and a blue light emitting device 100B) arranged in a matrix on the substrate 402a as a display region. A signal line driver 1803 and a scan line driver 1804 (drivers for image display) are provided around the display area. Note that the combination of adjacent display devices 100 constitutes one pixel 1802. Such a configuration allows some display devices 100 to be selected to emit light in accordance with signals from the signal line driver 1803 and the scan line driver 1804.
The above-described embodiment is particularly effective for a top emission structure that extracts light from the top (cathode side) of the substrate, and in this case, the thickness of the cathode film needs to be thin in order to extract light. For example, in the case of a metal cathode such as Mg-Ag, the thickness should generally be 30nm or less. Furthermore, when a transparent material such as InZnO is used on top of the substrate, the absorption of light emission by the thick film is increased. In this case, the thickness is appropriately set within a range in which the power consumption of the panel does not increase.
As described above, according to the present disclosure, an inorganic/organic/inorganic laminate structure currently used or a Thin Film Encapsulation (TFE) structure as an inorganic laminate structure is not formed on a cathode, thereby excluding CVD and inkjet processes. In particular, CVD processes require a longer time, which can reduce the required manufacturing time. To increase the deposition rate in a CVD process, it is often necessary to perform at high temperatures, which adversely affects the reliability of the OLED device. Therefore, eliminating the CVD process may also improve the reliability of the OLED device.
In addition, according to the CVD process, the generation of dust generates dark spots and reduces yield. In addition, the gas used in the CVD process chemically damages the film formation surface of the OLED display device. Therefore, these problems can be avoided by eliminating the CVD process.
In addition, although inorganic SiN is contained in TFExOyAnd/or SiNxAbsorbing blue light, but not forming a TFE laminate structure enhances EQE (EL intensity). Thus, the dissipation power can be reduced.
Further, inorganic SiN contained in TFExOyAnd/or SiNxIs rigid and generates a plurality of cracks when bent, which deteriorates the reliability of the OLED display device. Therefore, a laminate structure without TFE can provide a better structure of the folding OLED display.
The above description is only a specific embodiment of the present invention, and is not intended to limit the scope of the present invention. Any changes or substitutions that can be easily understood by those skilled in the art within the technical scope disclosed are within the scope of the present invention. Accordingly, the scope of the invention is to be accorded the full breadth of the claims.

Claims (7)

1. A display panel comprising a matrix of pixels, each pixel comprising three sub-pixels, each sub-pixel comprising:
a cathode layer;
a polarizer layer comprising an adhesive layer, wherein the adhesive layer is formed on the cathode layer, and H in the adhesive layer is at 85 ℃/85% RH2O and/or O2Has a permeability of 40 μm/h or less.
2. The display panel according to claim 1, wherein an inorganic compound barrier layer having a thickness of 1 μm or less is formed between the cathode layer and the adhesive layer.
3. The display screen of claim 1, wherein the adhesive layer is formed directly on the cathode layer.
4. A display screen according to any one of claims 1 to 3, wherein the adhesive layer has a thickness of 100 μm or less.
5. The display screen of any of claims 1-4, comprising:
an anode layer;
a light emitting unit including an organic light emitting layer formed on the anode layer; and
an encapsulation member covering at least a portion of a side surface of the anode, the light emitting unit, and the cathode layer.
6. A display screen according to any one of claims 1 to 5, wherein the cathode layer is a metal having a thickness of 30nm or less.
7. A terminal device, comprising:
the display screen of any one of claims 1-6; and
and the processor is used for controlling the display screen.
CN201980099744.4A 2019-08-30 2019-08-30 Display screen and terminal equipment Pending CN114303184A (en)

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