JP2013065405A - Display device and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device in which the color temperature is enhanced by a simple method without increasing the number of steps or the facility cost, and to provide a manufacturing method therefor.SOLUTION: The display device includes a plurality of barrier ribs provided linearly on a substrate, and two kinds of light-emitting element each having a plurality of light-emitting units provided between the barrier ribs and laminated between a first electrode and a second electrode with a connection layer interposed therebetween. One kind out of the two kinds of light-emitting element contains an n-type dopant and a p-type dopant in the connection layer, whereas the other kind of light-emitting element does not contain an n-type dopant or a p-type dopant in the connection layer.

Description

  The present disclosure relates to a display device that emits light using, for example, an organic electroluminescence (EL) phenomenon and a method for manufacturing the same.

  In order to improve the light emission efficiency of the organic EL element, for example, in Patent Document 1, an element (MPE) having a multi-photo emission structure (tandem structure) in which a plurality of organic layers (light emitting units) including a light emitting layer are stacked via a connection layer is used. Device).

  As an organic EL element (light emitting element) having a tandem structure, for example, development of a white light emitting element in which a light emitting unit having a blue light emitting layer and a light emitting unit having a yellow light emitting layer are stacked via a connection layer has been promoted. Yes. As the light emitting materials for the blue light emitting layer and the yellow light emitting layer, fluorescent materials emitting blue light or yellow light were used, respectively, but recently phosphorescent materials with higher luminous efficiency have been developed as yellow light emitting materials. And began to be used. On the other hand, a blue phosphorescent material having sufficient light emission performance has not been obtained. For this reason, in the tandem white organic EL element using a phosphorescent material for the yellow light emitting layer and a conventional fluorescent material as the material for the blue light emitting layer, the luminous efficiency is improved, but the emitted light has a blue intensity. Is emitted from yellow with insufficient color, ie, the color temperature is lowered. Therefore, there is a problem that the target chromaticity cannot be obtained when it is applied to a black and white monitor typified by an image interpretation monitor or the like.

  In order to solve this problem, for example, a method of adjusting the chromaticity by adding a blue light emitting element to the above-described display device that emits yellow light is considered.

JP 2006-73484 A

  However, in a display device in which a white light emitting element and a blue light emitting element are combined, it is necessary to form light emitting elements that emit different colors, that is, have different structures. For this reason, there existed a problem that the number of processes increased. Moreover, as the manufacturing method, a vapor deposition method is mentioned, for example. In order to form organic EL elements having different configurations using vapor deposition methods, it is possible to paint with a mask, but it is difficult to paint separately, especially when producing large panels, the mask will bend, It becomes more difficult. Furthermore, there is a problem that the equipment cost is high.

  The present technology has been made in view of such problems, and an object of the present technology is to provide a display device in which the color temperature is improved by a simple method and the manufacturing method thereof without increasing the number of steps and the equipment cost.

  A display device according to an embodiment of the present technology includes a plurality of light emission layers provided between a plurality of partition walls provided linearly on a substrate and between the first electrode and the second electrode via a connection layer. Two types of light-emitting elements each having a unit, one of which includes an n-type dopant and a p-type dopant in the connection layer, while the other includes an n-type dopant or a p-type dopant in the connection layer. It is not included.

The manufacturing method of the display device of the present technology includes the following steps (A) to (E).
(A) A step of forming a plurality of partition walls extending in one direction on the substrate (B) A step of forming a first light emitting unit between the partition walls (C) A connection layer having a plurality of layers is formed on the first light emitting unit. Step (D) Forming the second light-emitting unit on the connection layer Step (E) 2 by providing the connection layer with a region containing an n-type dopant and a p-type dopant and a region not containing an n-type dopant or a p-type dopant. A kind of light emitting element is formed.

  In the display device and the manufacturing method thereof according to the present technology, by using the partition wall as a mask, vapor deposition is performed, so that a single vapor deposition includes a region containing different contents, specifically, a region containing an n-type dopant or a p-type dopant. It is possible to form a non-existing region.

  According to the display device of the present technology and the method for manufacturing the display device, vapor deposition is performed using the partition walls as a mask. Therefore, regions having different contents are formed by a single vapor deposition. Specifically, a layer having a plurality of light-emitting units and a region containing an n-type dopant and a p-type dopant and a region not containing an n-type dopant or a p-type dopant among the plurality of layers. Can be formed. Thereby, two types of light emitting elements can be simultaneously formed by a simple method. Therefore, a display device with improved color temperature can be manufactured by a simple method without increasing the number of steps and the equipment cost.

3 is a plan view illustrating an example of a configuration of a display device according to an embodiment of the present disclosure. FIG. It is the schematic of the display apparatus shown in FIG. FIG. 3 is a diagram illustrating an example of a pixel drive circuit of the display device illustrated in FIG. 2. FIG. 2 is a partial cross-sectional view of the display device illustrated in FIG. 1. It is sectional drawing of the organic EL element which comprises the display apparatus shown in FIG. 2 shows a flow of a manufacturing process of the display device shown in FIG. It is a schematic diagram explaining the vapor deposition conditions of a connection layer. It is a characteristic view showing the relationship between a relative position and a relative film thickness. It is a characteristic view showing an emission spectrum. (A) is a perspective view showing the external appearance seen from the back side of the application example 1, (B) is a perspective view showing the external appearance seen from the front side. 12 is a perspective view illustrating an appearance of application example 2. FIG. (A) is a perspective view showing the external appearance seen from the front side of the application example 3, (B) is a perspective view showing the external appearance seen from the back side. 14 is a perspective view illustrating an appearance of application example 4. FIG. 14 is a perspective view illustrating an appearance of application example 5. FIG. (A) is a front view of the application example 6 in an open state, (B) is a side cross section thereof, (C) is a front view in a closed state, (D) is a left side view, and (E) is a right side view, (F) is a top view and (G) is a bottom view.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be given in the following order.
1. Embodiment (Display device having first lyophilic region and first lyophobic region in display region, and second lyophilic region in peripheral region)
1-1. Configuration of display area 1-2. Overall configuration of display device 1-3. Configuration of organic EL element 1-4. 1. Manufacturing method of display device Application examples

1. Embodiment (1-1. Configuration of Display Area)
FIG. 1 illustrates a planar configuration of a display device 1 according to an embodiment of the present disclosure. The display device 1 is used for an image interpretation monitor or the like. For example, the display device 1 includes a display area 2 in which a plurality of pixels 4 (here, white pixels 4W and blue pixels 4B) are arranged on a substrate 11, and the display area 2 A peripheral region 3 is provided so as to surround the. The plurality of pixels 4 (white pixels 4W and blue pixels 4B) are arranged in a matrix. Specifically, for example, as illustrated in FIG. 1, the white pixel 4 </ b> W and the blue pixel 4 </ b> B are linearly arranged so that the lateral directions of the pixels 4 having a rectangular shape for each color are adjacent to each other. The white pixel lines 4WL and the blue pixel 4 lines BL arranged in a straight line are alternately arranged in the longitudinal direction of the display region 2, for example. Furthermore, the display area 2 of the display device 1 of the present embodiment is provided with a plurality of partition walls 5 extending in the short direction. Between the partition walls 5, one white pixel line 4WL and one blue pixel line 4BL are provided. The arrangement method of each pixel 4 (4W, 4B) is not limited to this, and the white pixel 4W and the blue pixel 4B may be arranged in a straight line so that the lateral direction is adjacent to each color. In this case, the partition wall 5 extends in the longitudinal direction of the display area 2.

  On each color pixel 4W, 4B of the display area 2, an organic EL element 10 (10W, 10B; light emitting element) of a color corresponding to each color pixel 4W, 4B is provided. As will be described in detail later, the organic EL element 10 includes a lower electrode 12 (first electrode), a first light emitting unit 13A, a connection layer 14, a second light emitting unit 13B, an electron injection layer 15, and an upper electrode 16 (second electrode). ) Are stacked in this order (see FIG. 4).

(1-2. Overall configuration of display device)
FIG. 2 shows a block configuration of the display device 1 of the present embodiment. In the display device 1, as described above, the display region 2 in which a plurality of organic EL elements 10 </ b> W and 10 </ b> B are arranged in a matrix is formed on the substrate 11, and the peripheral region 3 is formed around the display region 2. Is provided. In the peripheral region 3, a signal line driving circuit 120 and a scanning line driving circuit 130, which are drivers for displaying images, are provided.

  A pixel drive circuit 140 is provided in the display area 2. FIG. 3 illustrates an example of the pixel driving circuit 140. The pixel drive circuit 140 is an active drive circuit formed below the lower electrode 12 described later. That is, the pixel drive circuit 140 includes a drive transistor Tr1 and a write transistor Tr2, a capacitor (holding capacitor) Cs between the transistors Tr1 and Tr2, a first power supply line (Vcc), and a second power supply line (GND). ) Has a white organic EL element 10W (or a blue organic EL element 10B) connected in series to the driving transistor Tr1. The drive transistor Tr1 and the write transistor Tr2 are configured by a general thin film transistor (TFT), and the configuration may be, for example, an inverted staggered structure (so-called bottom gate type) or a staggered structure (top gate type). There is no particular limitation.

  In the pixel driving circuit 140, a plurality of signal lines 120A are arranged in the column direction, and a plurality of scanning lines 130A are arranged in the row direction. The intersection of each signal line 120A and each scanning line 130A corresponds to one of the white organic EL element 10W and the blue organic EL element 10B. Each signal line 120A is connected to the signal line drive circuit 120, and an image signal is supplied from the signal line drive circuit 120 to the source electrode of the write transistor Tr2 via the signal line 120A. Each scanning line 130A is connected to the scanning line driving circuit 130, and a scanning signal is sequentially supplied from the scanning line driving circuit 130 to the gate electrode of the writing transistor Tr2 via the scanning line 130A.

(1-3. Configuration of organic EL element)
FIG. 4 illustrates a cross-sectional configuration of the display device 1 taken along a dashed line II ′ in FIG. As described above, the display device 1 is provided with the drive circuit 140 for driving the pixels 4 on the substrate 11 by, for example, the active matrix method, and the drive circuit 140 is provided with the drive transistor Tr1 (not shown). It has been. The drive transistor Tr1 is, for example, a bottom gate type thin film transistor (TFT), and specifically, a gate electrode, a gate insulating film, an oxide semiconductor layer, a channel protective film, and a source / drain electrode on the substrate 11. Are formed in this order. On the source / drain electrodes, a flattening layer for flattening the unevenness of the TFT over the entire surface of the substrate 11 is formed. On the TFT, an organic EL element 10 (10W, 10B) constituting the pixel 4 (4W, 4B) is provided.

  FIG. 5 shows a detailed cross-sectional configuration of the organic EL element 10 (10W, 10B) shown in FIG. In the present embodiment, the white organic EL element 10W and the blue organic EL element 10B have the same configuration, and the white organic EL element 10W and the blue organic EL element 10B arranged adjacent to each other between the partition walls 5 It is composed of continuous layers. As described above, the organic EL element 10 (10W, 10B) includes the lower electrode 12, the organic layer 13 including the first light emitting unit 13A and the second light emitting unit 13B, the electron injection layer 15, and the upper electrode 16 on the substrate 11. Are stacked in this order. The first light emitting unit 13A and the second light emitting unit 13B are each formed by laminating a hole injection layer 13a1, 13a2, a hole transport layer 13b1, 13b2, a light emitting layer 13c1, 13c2, and an electron transport layer 13d1, 13d2 in order from the lower electrode 12 side. It is made. The first light emitting unit 13A and the second light emitting unit 13B are stacked via the connection layer 14.

  This organic EL element 10 (10W, 10B) emits light emitted when holes injected from the lower electrode 12 and electrons injected from the upper electrode 16 are recombined in the light emitting layers 13c1 and 13c2. This is a top emission type (top emission type) display element that extracts light from the opposite side (upper electrode 16 side). By using the top emission type organic EL element, the aperture ratio of the light emitting portion of the display device is improved. The organic EL element 10 (10W, 10B) of the present disclosure is not limited to such a configuration. For example, a transmissive display that takes out light from the substrate 11 side, that is, a bottom emission type (bottom emission type) display. It is good also as an element.

  The substrate 11 is a support on which a plurality of organic EL elements 10 are arranged and formed on one main surface side, and may be a well-known one, for example, quartz, glass, metal foil, or a resin film, A sheet or the like is used. Of these, quartz and glass are preferable. In the case of resin, methacrylic resins represented by polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene naphthalate ( Polyesters such as PBN) or polycarbonate resins may be mentioned, but it is necessary to perform a laminated structure and surface treatment that suppress water permeability and gas permeability.

  The lower electrode 12 has, for example, a thickness in the stacking direction (hereinafter simply referred to as a thickness) of 10 nm or more and 3000 nm or less, and a work function from the vacuum level of the electrode material in order to efficiently inject holes into the organic layer 13. It is preferable to use one having a large. Specifically, a simple substance or an alloy of a metal element such as chromium (Cr), gold (Au), platinum (Pt), nickel (Ni), copper (Cu), tungsten (W) or silver (Ag) can be used. . The lower electrode 12 includes a metal film made of a single element or an alloy of these metal elements, an oxide of indium and tin (Indium Tin Oxide: ITO), InZnO (Indium Zinc Oxide: zinc oxide), zinc oxide (ZnO). And a laminated structure of a transparent conductive film such as an alloy of aluminum (Al).

  Particularly in the case of a top emission type display element, the lower electrode 12 uses an electrode having a high reflectivity, whereby the light extraction efficiency to the outside is improved by the interference effect and the high reflectivity effect. For example, the lower electrode 12 preferably has a laminated structure of a first layer having excellent light reflectivity and a second layer having a light transmittance and a large work function provided thereon. Here, it is preferable to use an alloy mainly containing Al as a main component for the first layer, and an element having a work function relatively smaller than that of Al as a main component is used as a subcomponent. As such a minor component, it is preferable to use a lanthanoid series element. Although the work function of the lanthanoid series elements is not large, the inclusion of these elements improves the stability of the anode and also satisfies the hole injection property of the anode. In addition to lanthanoid series elements, elements such as silicon (Si) and copper (Cu) may be used as subcomponents.

  For the second layer, an Al alloy oxide, molybdenum (Mo) oxide, zirconium (Zr) oxide, Cr oxide, and tantalum (Ta) oxide can be used. For example, when the second layer is an oxide layer (including a natural oxide film) of an Al alloy containing a lanthanoid series element as a subcomponent, the oxide of the lanthanoid series element has a high transmittance, so The transmittance of the two layers becomes good. Thereby, the reflectance at the surface of the first layer is kept high. Moreover, the hole injection characteristic of the lower electrode 12 is improved by using a transparent conductive layer such as ITO or IZO as the second layer. In addition, since ITO and IZO have a large work function, the charge injection efficiency is improved by using the ITO and IZO on the side in contact with the substrate 11, that is, the first layer, and the adhesion between the lower electrode 12 and the substrate 11 is improved. Can do.

  When the driving method of the display device 1 configured using the organic EL element 10 is an active matrix method, the lower electrode 12 is patterned for each pixel, and a driving transistor (not shown) provided on the substrate 11 is provided. ) Are connected to each other. In this case, a partition wall 5 (see FIG. 4) is provided on the lower electrode 12, and the surface of the lower electrode 12 of each pixel 4W, 4B is exposed from the opening of the partition wall 5.

  The organic layer 13 includes a first light emitting unit 13A and a second light emitting unit 13B connected by a connection layer 14 described later. The first light emitting unit 13A has a configuration in which, for example, a hole injection layer 13a1, a hole transport layer 13b1, a light emitting layer 13c1, and an electron transport layer 13d1 are stacked in this order from the lower electrode 12 side. The second light emitting unit 13B has a configuration in which a hole injection layer 13a2, a hole transport layer 13b2, a light emitting layer 13c2, and an electron transport layer 13d2 are stacked in this order from the lower electrode 12 side. The organic layer 13 is formed by, for example, a vacuum deposition method, as will be described in detail later. The upper surface of the organic layer 13 is covered with the upper electrode 16. Although the film thickness of each layer which comprises the organic layer 13, a constituent material, etc. are not specifically limited, An example is shown below.

  The hole injection layers 13a1 and 13a2 are buffer layers for increasing the efficiency of hole injection into the light emitting layers 13c1 and 13c2 and preventing leakage. The thickness of the hole injection layer 13A is preferably, for example, 5 nm to 200 nm, and more preferably 8 nm to 130 nm. The constituent material of the hole injection layer 13A may be appropriately selected in relation to the electrode and the material of the adjacent layer. For example, polyaniline, polythiophene, polypyrrole, polyphenylene vinylene, polythienylene vinylene, polyquinoline, polyquinoxaline, and derivatives thereof. , Conductive polymers such as polymers containing an aromatic amine structure in the main chain or side chain, metal phthalocyanines (such as copper phthalocyanine), and carbon. Specific examples of the conductive polymer include oligoaniline and polydioxythiophene such as poly (3,4-ethylenedioxythiophene) (PEDOT).

  The hole transport layers 13b1 and 13b2 are for increasing the efficiency of hole transport to the light emitting layers 13c1 and 13c2. The thickness of the hole transport layer 16B depends on the entire configuration of the element, but is preferably, for example, 5 nm to 200 nm, and more preferably 8 nm to 130 nm. As a material constituting the hole transport layers 13b1 and 13b2, a light-emitting material soluble in an organic solvent, for example, polyvinyl carbazole, polyfluorene, polyaniline, polysilane or a derivative thereof, and an aromatic amine in a side chain or a main chain Polysiloxane derivatives, polythiophene and its derivatives, polypyrrole, Alq3, or the like can be used.

  The light emitting layers 13c1 and 13c2 emit light by recombination of electrons and holes when an electric field is applied. The light emitting layer 13c1 is, for example, a blue light emitting layer that emits blue light, and the light emitting layer 13c2 is, for example, a yellow light emitting layer that emits yellow light. The thickness of the blue light emitting layer is preferably 2 nm to 50 nm, and more preferably 5 nm to 30 nm, although it depends on the overall structure of the element. Although the thickness of a yellow light emitting layer is based also on the whole structure of an element, it is preferable that it is 10 nm-200 nm, for example, More preferably, it is 13 nm-100 nm.

  As a material constituting the light emitting layer 13C, a material that emits light of a desired color may be used. When a low molecular material having a molecular weight of about 1 to 5000 is used as the light emitting material, it is preferable to use a mixture of two or more kinds of light emitting materials as the host material and the dopant material.

  As a material of the blue light emitting layer (light emitting layer 13c1), for example, blue or green light emission is generated by combining a dopant material of a blue or green fluorescent dye with an anthracene compound as a host material. Examples of the dopant material include materials having high luminous efficiency, for example, low-molecular fluorescent materials, organic light-emitting materials such as phosphorescent dyes and metal complexes. Specifically, it is a compound having a peak wavelength in the range of about 400 nm to 490 nm. As such a compound, an organic substance such as a naphthalene derivative, anthracene derivative, naphthacene derivative, styrylamine derivative, or bis (azinyl) methene boron complex is used. Among these, it is preferable to select from aminonaphthalene derivatives, aminoanthracene derivatives, aminochrysene derivatives, aminopyrene derivatives, styrylamine derivatives, and bis (azinyl) methene boron complexes.

  Examples of the material of the yellow light emitting layer (light emitting layer 13c2) include a phosphorescent or fluorescent material having at least one peak wavelength in a region of 500 nm to 750 nm. Specific examples include luminescent polymers such as polyfluorene polymer derivatives, polyphenylene vinylene derivatives, polyphenylene derivatives, polyvinyl carbazole derivatives, and polythiophene derivatives. Moreover, as a dopant material mixed when using a low molecular weight material as a host material, for example, a phosphorescent metal complex compound, specifically, a metal selected from Groups 7 to 11 of the periodic table as a central metal, for example, Beryllium (Be), boron (B), zinc (Zn), cadmium (Cd), magnesium (Mg), gold (Au), silver (Ag), palladium (Pd), platinum (Pt), aluminum (Al), Gadolinium (Ga), yttrium (Y), scandium (Sc), ruthenium (Ru), rhodium (Rh), osmium (Os), iridium (Ir), or the like is preferably used.

  The light emitting layers 13c1 and 13c2 may be, for example, hole transporting light emitting layers that also serve as the above-described hole transporting layers 13b1 and 13b2, and electron transporting properties that also serve as electron transporting layers 13d1 and 13d2 described later. It is good also as a light emitting layer.

  The electron transport layers 13d1 and 13d2 are for increasing the efficiency of electron transport to the light emitting layers 13c1 and 13c2. Although the thickness of the electron transport layers 13d1 and 13d2 depends on the overall structure of the device, it is preferably, for example, 5 nm to 200 nm, and more preferably 10 nm to 180 nm.

  As a material for the electron transport layers 13d1 and 13d2, an organic material having an excellent electron transport ability is preferably used. By increasing the transport efficiency of the light emitting layers 13c1 and 13c2, a change in emission color due to the electric field strength described later is suppressed. Specifically, it is preferable to use, for example, an arylpyridine derivative or a benzimidazole derivative. Thus, high electron supply efficiency is maintained even at a low driving voltage. In addition, alkali metals, alkaline earth metals, rare earth metals and oxides thereof, composite oxides, fluorides, carbonates, and the like can be given.

  The connection layer 14 is for connecting the first light emitting unit 13A and the second light emitting unit 13B. The connection layer 14 has a configuration in which, for example, the electron supply layer 14A, the intermediate layer 14B, and the hole injection layer 14C are stacked in this order from the lower electrode 12 side, and the film thickness of the connection layer 14 as a whole depends on the device configuration. For example, the thickness is preferably 1 nm to 100 nm, more preferably 10 nm to 50 nm.

  The material constituting the connection layer 14 is appropriately selected depending on the characteristics of the adjacent organic layer 13 (particularly, the electron transport layer 13d1 in the first light emitting unit 13A and the hole injection layer 13a2 in the second light emitting unit 13B). Hereinafter, examples of materials of the electron supply layer 14A, the intermediate layer 14B, and the hole injection layer 14C will be described.

  The electron supply layer 14A has an electron donor property, and examples of the material include an electron transport material doped with an n-type dopant, specifically, for example, the materials listed in the electron transport layers 13d1 and 13d2. Can be used. Examples of the n-type doped material include alkali metals, alkaline earth metals, or oxides, composite oxides, fluorides, and organic complexes thereof.

  In particular, when the electron mobility of the electron transport layer 15d1 of the first light emitting unit 13A is relatively large and there is no large injection failure between the electron transport layer 15d1 and the electron supply layer 14A, the electronegativity is small and the electron donor is small. A material excellent in properties can be mentioned. Among these, a material having a small light absorption in the visible light region in a film state is preferable. Specifically, for example, alkali metals such as Li, Na, K, Rb, and Cs or alkaline earth metals such as Be, Mg, Ca, Sr, Ba, and Ra can be used.

  The electron supply layer 14A may be formed of the above alkali metal or alkaline earth metal alone, but it is formed by forming a co-evaporated film with Ag, In, Al, Si, Ge, Au, Cu, Zn or the like. The stability of the state can be improved. The co-evaporated film may be formed as a mixed film using three or more kinds of the above metals. In that case, in order to suppress the optical light absorption loss as much as possible, it is preferable to make the film thickness as thin as possible while exhibiting the function and ensuring the stability of the film. For example, a suitable film thickness is 5 nm or less. Further, the electron supply layer 14A formed by co-evaporation may form a mixed film using the alkali metal or alkaline earth metal and an organic material. As the organic material to be mixed, a material having a high electron transporting property is preferable, but a material having a high insulating property or a hole transporting material may be used. For example, a material such as Alq3 or α-NPD can be used. From the viewpoint of stability in the alkali metal and alkaline earth metal film, it is preferable to use an organic material that forms a metal complex with these alkali metal and alkaline earth metal. Specifically, for example, an organic material having a skeleton that easily forms a complex such as bathophenanthroline or bathocuproine or an oxadiazole skeleton can be given.

  The intermediate layer 14B has a charge transporting property and includes at least one material having an electron transporting property, a hole transporting property, or both charge transporting properties. Specific examples include arylpyridine derivatives and benzimidazole derivatives.

  The hole injection layer 14C has an electron acceptor property, and for example, a hole transport material is used as the material thereof. In the hole injection layer 14C of the present embodiment, two types of regions having different constituent materials are provided in the layer. Specifically, a region 14CW containing a p-type dopant in addition to the hole transport material is provided on the white organic EL element 10W, and a region 14CB not containing the p-type dopant is provided on the blue organic EL element 10B. . Accordingly, the white organic EL element 10W and the blue organic EL element 10B can emit different light emission while having the same element configuration.

  As the hole transporting material, for example, the materials listed in the hole transporting layers 15b1 and 15b2 can be used. Examples of the p-type doping material include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (F4-TCNQ) and hexaazacyanotriphenylene (HAT-6CN). . In particular, when there is no large injection failure between the hole injection layer 15a2 and the hole supply layer 14C of the second light emitting unit 13B, the same concept as the material selection in the electron supply layer 14A described above may be used. For example, an organic material having excellent electron acceptor properties can be used. Specifically, an electron acceptor organic material having a skeleton such as azatriphenylene or TCNQ can be formed as a single layer or a mixed film with a metal or the like. However, the present invention is not limited to this, and an organic material having a high hole mobility may be formed of a single layer or a mixed film with a metal or the like in the same manner as the electron acceptor organic material. Here, the metal is, for example, an alkali metal, an alkaline earth metal containing Mg, or a group IIIB or group IVB metal in the periodic table. In addition, like the electron supply layer 14A, a material that absorbs light in the visible light region in a film state is preferable. Furthermore, it is preferable to reduce the film thickness as much as possible, while maintaining its function as a film in order to suppress the optical light absorption loss as much as possible. It is a suitable film thickness.

  The n-type doped material, the charge transporting material, and the p-type doped material are merely examples, and electrons or holes are efficiently transported to the first light emitting unit layer 13A and the second light emitting unit 13B in the connection layer 14, respectively. It only has to be possible.

  The electron injection layer 15 is for increasing the efficiency of electron injection into the light emitting layers 13c1 and 13c2. Although the thickness of the electron injection layer 15 is dependent on the whole structure of an element, it is preferable that it is 5 nm-200 nm, for example, More preferably, it is 10 nm-180 nm. As a material of the electron injection layer 15, it is preferable to use an organic material having an excellent electron injection ability. Specifically, the materials mentioned in the electron transport layers 13d1 and 13d2 can be used.

  The upper electrode 16 is made of, for example, a material having a thickness of about 10 nm, good light transmittance, and a small work function. Moreover, light extraction can be ensured also by forming a transparent conductive film using an oxide. In this case, ZnO, ITO, IZnO, InSnZnO, or the like can be used. Furthermore, the upper electrode 16 may be a single layer, but here has a structure in which, for example, the first layer 16A, the second layer 16B, and the third layer 16C are stacked in order from the lower electrode 12 side.

The first layer 16A is preferably formed of a material having a small work function and good light transmittance. Specifically, alkaline earth metals such as calcium (Ca) and barium (Ba), alkali metals such as lithium (Li) and cesium (Cs), indium (In), magnesium (Mg), and silver (Ag) Is mentioned. Further examples include alkali metal oxides such as Li ₂ O, Cs ₂ Co ₃ , Cs ₂ SO ₄ , MgF, LiF, and CaF ₂ , alkali metal fluorides, alkaline earth metal oxides, and alkaline earth fluorides.

  The second layer 16B is made of a material having light transmissivity such as a thin-film MgAg electrode or Ca electrode and having good conductivity. The third layer 16C is preferably made of a transparent lanthanoid oxide in order to suppress electrode deterioration. Thereby, it becomes possible to use as a sealing electrode which can take out light from the upper surface. In the case of the bottom emission type, gold (Au), platinum (Pt), AuGe, or the like is used as the material of the third layer 15C.

  The first layer 16A, the second layer 16B, and the third layer 16C are formed by a technique such as a vacuum evaporation method, a sputtering method, or a plasma CVD method. When the driving method of the display device configured using this display element is the active matrix method, the upper electrode 16 is separated from the lower electrode 12 by the partition wall 5 and the organic layer 13 that cover a part of the lower electrode 12. It is formed in a solid film shape on the substrate 11 in an insulated state, and may be used as a common electrode for each pixel.

  The upper electrode 16 may be a mixed layer containing an organic light emitting material such as an aluminum quinoline complex, a styrylamine derivative, or a phthalocyanine derivative. In this case, a layer having optical transparency such as MgAg may be additionally provided as the third layer 16C (not shown). Needless to say, the upper electrode 16 is not limited to the laminated structure as described above, and may have an optimum combination and laminated structure according to the structure of the device to be manufactured. For example, the configuration of the upper electrode 16 of the present embodiment includes an inorganic layer (first layer) that promotes functional separation of each electrode layer, that is, electron injection into the organic layer 13, and an inorganic layer (second layer) that controls the electrode. ) And an inorganic layer (third layer) protecting the electrode. However, the inorganic layer that promotes electron injection into the organic layer 13 may also serve as the inorganic layer that controls the electrode, and these layers may have a single-layer structure.

  Further, when the organic EL element 10 has a cavity structure, it is preferable that the upper electrode 16 is configured using a transflective material. As a result, emitted light that has been subjected to multiple interference between the light reflecting surface on the lower electrode 12 side and the light reflecting surface on the upper electrode 16 side is extracted from the upper electrode 16 side. In this case, the optical distance between the light reflecting surface on the lower electrode 12 side and the light reflecting surface on the upper electrode 16 side is defined by the wavelength of light to be extracted, and the film thickness of each layer so as to satisfy this optical distance. Is set. In such a top emission type display element, it is possible to improve the light extraction efficiency to the outside and control the emission spectrum by positively using this cavity structure.

The protective layer 17 is for preventing moisture from entering the organic layer 13, and is formed with a thickness of, for example, 2 to 3 μm using a material having low permeability and low water permeability. The material of the protective layer 17 may be made of either an insulating material or a conductive material. As the insulating material, an inorganic amorphous insulating material such as amorphous silicon (α-Si), amorphous silicon carbide (α-SiC), amorphous silicon nitride (α-Si _1-x N _x ), amorphous carbon (α -C) is preferred. Such an inorganic amorphous insulating material does not constitute grains, and thus has low water permeability and becomes a good protective film.

  The sealing substrate 18 is located on the upper electrode 16 side of the organic EL element 10 (10W, 10B), and seals the organic EL element 10 together with an adhesive layer (not shown). The sealing substrate 18 is made of a material such as glass that is transparent to the light generated in the organic EL element 10 (10W, 10B). The sealing substrate 18 may be provided with, for example, a color filter and a light shielding film (not shown) as a black matrix. As a result, the light generated in the organic EL element 10 is color-divided and taken out, and the external light reflected in the wiring between the organic EL elements 10 is absorbed to improve the contrast.

  The organic EL display device 1 can be manufactured as follows, for example.

(Process of forming the lower electrode 12)
FIG. 6 shows the flow of the manufacturing method of the organic EL display device 1. First, the lower electrode 12 is formed on the entire surface of the substrate 11 made of the above-described material (step S101). Specifically, a conductive film made of, for example, Al is formed, and the conductive film is patterned to form the lower electrode 12 for each of the white organic EL element 10W and the blue organic EL element 10B. At that time, the lower electrode 12 is brought into conduction with the drain electrode of the driving transistor through the contact hole of the planarization layer.

(Step of forming partition wall 5)
Subsequently, the partition walls 5 are formed on the lower electrode 12 and the planarization layer (not shown) (step S102). Specifically, when the height of the partition wall 5 is several tens of μm or more, a dry film is attached and processed into a predetermined shape. When the height of the partition wall 5 is relatively low, less than several tens of μm, for example, a material such as polyimide or acrylic is applied and processed into a predetermined shape using a photolithography technique and an etching technique.

(Step of forming the first light emitting unit 13A)
Hereinafter, the organic layer 13 and the connection layer 14 are formed using a line vapor deposition method (step S103). Specifically, for example, a material such as polyaniline is put into a long first line-type vapor deposition source 21 (see FIG. 7), and the first line-type vapor deposition source 21 and the substrate 11 to be vapor-deposited are relatively moved. Then, the hole injection layer 13a1, the hole transport layer 13b1, the blue light emitting layer 13c1, and the electron transport layer 13d1 are sequentially formed. The first line type vapor deposition source 21 is provided with a plurality of openings along the longitudinal direction, and the vapor deposition material is ejected from each opening. In addition, a limiting plate 21A (see FIG. 7) is provided in the first line-type vapor deposition source 21 in the longitudinal direction so as to sandwich each opening, thereby defining the film forming width in the transport direction.

(Step of forming the connection layer 14)
After forming the first light emitting unit 13A, the connection layer 14 is formed (step S104). Specifically, the electron supply layer 14A and the intermediate layer 14B containing the n-type dopant are formed using, for example, a method similar to the method for forming the first light emitting unit 13A. When two or more types of materials are used as in the electron supply layer 14A, a plurality of types of materials may be mixed and evaporated in the first line type evaporation source 21, or in a range facing the film formation region. A plurality of line-type vapor deposition sources corresponding to the number of materials used in the device may be arranged and vaporized by vaporizing each material individually.

Subsequently, a hole supply layer 14C is formed on the intermediate layer 14B. In the present embodiment, the hole supply layer 14C on the white organic EL element 10W contains a p-type dopant, but the hole supply layer 14CB on the blue organic EL element 10B does not contain a p-type dopant. Such a hole supply layer 14C is formed, for example, by forming a film as follows. FIG. 7A shows the positional relationship between the substrate 11, the first line evaporation source 21 that evaporates the hole host material, and the second line evaporation source 22 that evaporates the p-type dopant. The hole supply layer 14C includes a distance (H) between the substrate 11 and the first line deposition source 21 in the deposition apparatus, a second line deposition source 22 that evaporates the first line deposition source 21 and the p-type dopant, and The following formulas (Formula 1 and Formula 2) that define the distance (T), the height (h) of the partition walls 5, the distance (t) between the partition walls 5, and the film formation width (w) in the transport direction of the substrate 11 By satisfying this, as shown in FIG. 7B, it is possible to simultaneously form the region 14CW including the p-type dopant and the region 14CB not including the p-type dopant in the hole supply layer 14C.
(Equation 1)
h × (Tw / 2−t / 2) / (H−h)> 0 (1)
(Equation 2)
t−h × (Tw / 2−t / 2) / (H−h)> 0 (2)
(H: height of partition wall, T: distance between first deposition source and second deposition source, w: film formation width in substrate transport direction, t: distance between partition walls, H: distance between substrate and first deposition source distance)

  FIG. 8 shows a hole host material (FIG. 8A) and a p-type dopant at each position between the partition walls 5 when h = 50 μm, T = 260 mm, w = 100 mm, t = 300 μm, and H = 100 mm. The film thickness in FIG. 8B was measured. The hole host material deposited from the first line deposition source 21 disposed at a position facing the deposition region has a uniform film thickness. On the other hand, the p-type dopant deposited from the second line deposition source 22 arranged on the right side (blue pixel line 5BL side) with respect to the deposition region so as to be deposited obliquely with respect to the deposition surface is on the blue pixel 5B. It can be seen that is not deposited on the white pixel 5W. From these results, it can be seen that coating can be performed on a predetermined region by performing vapor deposition so as to satisfy the above conditions.

(Step of forming the second light emitting unit 13B)
Next, the second light emitting unit 13B is formed on the connection layer 14 (step S105). Specifically, the hole injection layer 13a2, the hole transport layer 13b2, the yellow light-emitting layer 13c2, and the electron transport layer 13d2 are sequentially formed using the same method as the first light-emitting unit 13A.

  FIG. 9 shows emission spectra measured in a region 14CW containing a p-type dopant (FIG. 9A) and a region 14CB not containing a p-type dopant (FIG. 9B). In FIG. 9A, it can be seen that there are peaks in both the blue wavelength region and the yellow wavelength region, whereas in FIG. 9B, there are peaks only in the blue wavelength region. From this, it can be seen that the white organic EL element 10W and the blue organic EL element 10B were formed between the partition walls 5 in the same process.

(Step of forming electron injection layer 13C and upper electrode 15)
Subsequently, after forming the second light emitting unit 13B, the electron injection layer 13C and the upper electrode 15 are formed on the entire surface of the electron transport layer 13c2 (steps S106 and S107). Specifically, LiF is vacuum-deposited to form an electron injection layer 13C having a deposition layer degree of 0.01 nm / sec or less and a film thickness of about 0.3 nm, and then Ca is vacuumed as the first layer of the upper electrode 15. The upper electrode 15 is formed by forming a film with a thickness of about 3 nm by a vapor deposition method, and forming MgAg as a second layer with a thickness of about 5 nm by a vacuum vapor deposition method.

  After the upper electrode 15 is formed, the protective layer 16 and the sealing substrate 17 are formed. Specifically, as a protective film, for example, SiN is formed to a film thickness of 2 to 3 μm by a film forming method in which the energy of film forming particles is small, for example, vapor deposition or CVD. Thereafter, for example, UV resin or thermosetting resin is applied and bonded to the sealing substrate 17 for sealing. Thus, the display device 1 shown in FIGS. 1, 2, and 4 is completed.

  The first light emitting unit 13A, the connection layer 14, the second light emitting unit 13B, the electron injection layer 13C, the upper electrode 15 and the protective film 16 are preferably formed in the same film forming apparatus without being exposed to the atmosphere. Is performed continuously. Thereby, deterioration of the organic layer 13 due to moisture in the atmosphere is prevented.

  In the display device 1, a scanning signal is supplied from the scanning line driving circuit 130 to the pixel via the gate electrode of the writing transistor Tr 2, and an image signal is held from the signal line driving circuit 120 via the writing transistor Tr 2. The capacitance Cs is held. That is, the driving transistor Tr1 is controlled to be turned on / off according to the signal held in the holding capacitor Cs, whereby the driving current Id is injected into the white organic EL element 10W and the blue organic EL element 10B, and holes and electrons are generated. Recombination causes light emission. This light is transmitted through the lower electrode 12 and the substrate 11 in the case of bottom emission (bottom emission), and is transmitted through the upper electrode 15 and the sealing substrate 18 in the case of top emission (top emission). .

  In the display device 1 and the manufacturing method thereof according to the present embodiment, the hole supply layer of the connection layer 14 that connects the first light emitting unit 13A that emits blue light and the second light emitting unit 13B that emits yellow light. When 14C is formed, vapor deposition is performed so as to satisfy the vapor deposition conditions shown in the above formulas 1 and 2. Thereby, the region 14CW including the p-type dopant and the region 14CB not including the p-type dopant are formed in the hole supply layer 14C by a single vapor deposition process.

  As described above, in the display device 1 and the manufacturing method thereof according to the present embodiment, one of the connection layers composed of a plurality of layers (here, the hole supply layer 14 </ b> C) is vapor deposition conditions represented by the above-described formulas 1 and 2. It was made to vapor-deposit so that it might satisfy. Thereby, the partition 5 provided outside the white organic EL element 10W and the blue organic EL element 10B arranged adjacent to each other (particularly, the partition provided on the blue organic EL element 10B side) serves as a mask, and the holes In the supply layer 14C, the region 14CW including the p-type dopant and the region 14CB not including the p-type dopant are formed in the same process. Thereby, the white organic EL element 10W and the blue organic EL element 10B can be formed simultaneously without performing multi-step color separation. Therefore, it is possible to provide the display device 1 having a higher color temperature than that of the conventional light emitted from yellow without increasing the number of steps and the equipment cost.

  Further, since it is not necessary to provide a separate mask between the substrate 11 and the vapor deposition source, the utilization efficiency of the vapor deposition material is improved. That is, the material cost can be reduced.

  The display device 1 can be mounted on the electronic devices shown in the following application examples 1 to 6, for example.

2. Module and Application Examples Hereinafter, application examples of the display device 1 described in the above embodiment will be described. The display device 1 according to the above embodiment is a monochrome terminal device such as an image interpretation monitor, or a color terminal using a color filter or the like, so that a portable terminal device such as a television device, a digital camera, a notebook personal computer, a mobile phone, or the like The present invention can be applied to display devices of electronic devices in various fields that display video signals input from the outside or video signals generated inside such as video cameras as images or videos.

(module)
The display device 1 according to the above-described embodiment is incorporated into various electronic devices such as application examples 1 to 5 to be described later, for example, as a module illustrated in FIG. In this module, for example, a region 210 exposed from the protective layer 20 and the sealing substrate 30 is provided on one side of the substrate 11, and wirings of the signal line driving circuit 120 and the scanning line driving circuit 130 are provided in the exposed region 210. An external connection terminal (not shown) is formed by extending. The external connection terminal may be provided with a flexible printed circuit (FPC) 220 for signal input / output.

(Application example 1)
FIG. 11 illustrates an appearance of a television device to which the display device 1 of the above embodiment is applied. The television apparatus has, for example, a video display screen unit 300 including a front panel 310 and a filter glass 320, and the video display screen unit 300 is configured by the display devices 1 to 1G according to the above embodiments. ing.

(Application example 2)
FIG. 12 shows the appearance of a digital camera to which the display device 1 of the above embodiment is applied. The digital camera includes, for example, a flash light emitting unit 410, a display unit 420, a menu switch 430, and a shutter button 440. The display unit 420 includes the display devices 1 to 1G according to the above embodiments. Has been.

(Application example 3)
FIG. 13 shows the appearance of a notebook personal computer to which the display device 1 of the above embodiment is applied. The notebook personal computer has, for example, a main body 510, a keyboard 520 for inputting characters and the like, and a display unit 530 for displaying an image. The display unit 530 is a display device according to the above embodiment. 1 to 1G.

(Application example 4)
FIG. 14 shows the appearance of a video camera to which the display device 1 of the above embodiment is applied. This video camera has, for example, a main body 610, a subject photographing lens 620 provided on the front side surface of the main body 610, a start / stop switch 630 at the time of photographing, and a display 640. 640 includes the display devices 1 to 1G according to the above-described embodiment.

(Application example 5)
FIG. 15 shows the appearance of a mobile phone to which the display device 1 of the above embodiment is applied. For example, the mobile phone is obtained by connecting an upper housing 710 and a lower housing 720 with a connecting portion (hinge portion) 730, and includes a display 740, a sub-display 750, a picture light 760, and a camera 770. Yes. The display 740 or the sub-display 750 is configured by the display devices 1 to 1G according to the above embodiment.

  The present technology has been described with reference to one embodiment. However, the present technology is not limited to the above-described embodiment, and various modifications can be made. For example, in the above embodiment, each of the light emitting layers 13c1 and 15c2 is a single layer. However, the present invention is not limited to this and may have a laminated structure. For example, the light emitting layer 13c1 may be a stack of a red light emitting layer and a green light emitting layer, and the light emitting layer 13c2 may be a single layer of a blue light emitting layer to form a white light emitting element. In addition, the light emitting layer 13c1 may be an orange light emitting layer and the light emitting layer 13c2 may be a blue-green light emitting layer to form a white light emitting element.

  In the above embodiment, the region 14CW and the region 14CB not including the dopant are provided in the hole supply layer 14C in the connection layer 14, but the light emitting layer 13c1 of the first light emitting unit 13A is a yellow light emitting layer, When the light emitting layer 13c2 of the single light emitting unit 13B emits blue light, and the region 14AW including the dopant and the region 14AB not including the dopant are provided in the electron supply layer 14A, the same effect as in the above embodiment can be obtained.

  Further, the material and thickness of each layer described in the above embodiment, the film formation method, the film formation conditions, and the like are not limited, and may be other materials and thicknesses, or other film formation methods and film formation. It is good also as conditions. For example, in the first embodiment, an oxide semiconductor is used as a channel in the TFT 20, but the present invention is not limited to this, and silicon, an organic semiconductor, or the like may be used.

  Moreover, in the said embodiment, although the structure of organic EL element 10W, 10B etc. was mentioned concretely and demonstrated, it is not necessary to provide all the layers and you may further provide other layers. For example, the light emitting layer 13C may be formed directly without forming the hole transport layer 13B on the hole injection layer 13A.

  Furthermore, in addition to the above-described methods, the organic layer 13 is formed by a coating method such as a spin coating method, a dipping method, a doctor blade method, a discharge coating method, a spray coating method, an ink jet method, an offset printing method, a relief printing method, an intaglio printing method. Formation by a printing method such as a printing method, a screen printing method, or a micro gravure coating method is also possible, and a dry process and a wet process may be used in combination depending on the properties of each organic layer and each member.

  In the above embodiment, the case of an active matrix display device has been described. However, the present technology can also be applied to a passive matrix display device. Furthermore, the configuration of the pixel driving circuit for active matrix driving is not limited to that described in the above embodiment, and a capacitor or a transistor may be added as necessary. In that case, a necessary driving circuit may be added in addition to the signal line driving circuit 120 and the scanning line driving circuit 130 described above in accordance with the change of the pixel driving circuit.

In addition, this technique can also be set as the following structures.
(1) A plurality of partition walls linearly provided on a substrate, and a plurality of light emitting units provided between the partition walls and stacked between a first electrode and a second electrode via a connection layer. Two types of light emitting elements, one of which includes an n-type dopant and a p-type dopant in the connection layer, while the other includes an n-type dopant or a p-type dopant in the connection layer. Display device not included.
(2) The display device according to (1), wherein the connection layer includes a first layer including an electron transporting host material and a second layer including a hole transporting host material.
(3) The light emitting unit has, in order from the substrate side, a hole injection / transport layer having hole injection or hole transportability, a light emitting layer, an electron injection / transport layer having electron injection or electron transportability, The display device according to (1) or (2).
(4) The display device according to any one of (1) to (3), wherein the light emitting element is a blue light emitting element and a white light emitting element.
(5) Forming a plurality of partition walls extending in one direction on the substrate, forming a first light emitting unit between the partition walls, and forming a connection layer having a plurality of layers on the first light emitting unit. Including a step and a step of forming a second light emitting unit on the connection layer, and providing the connection layer with a region containing an n-type dopant and a p-type dopant and a region not containing an n-type dopant or a p-type dopant. A method for manufacturing a display device in which two types of light-emitting elements are formed by:
(6) In the region including and not including the n-type dopant or p-type dopant in the connection layer, the height of the partition and the positional relationship between the substrate, the first evaporation source, and the second evaporation source are expressed by the following formulas: The method for manufacturing a display device according to (5), wherein the display device is arranged so as to satisfy 1 and Formula 2, and is formed by vapor deposition using the partition as a mask.
(Equation 1)
h × (Tw / 2−t / 2) / (H−h)> 0 (1)
(Equation 2)
t−h × (Tw / 2−t / 2) / (H−h)> 0 (2)
(H: height of partition wall, T: distance between first deposition source and second deposition source, w: film formation width in substrate transport direction, t: distance between partition walls, H: distance between substrate and first deposition source distance)
(7) The region including and not including the n-type dopant or the p-type dopant in the connection layer is formed by depositing the second vapor deposition source in an oblique direction with respect to the vapor deposition surface of the substrate. Method of manufacturing the display device.

DESCRIPTION OF SYMBOLS 1 ... Display apparatus, 2 ... Display area, 3 ... Peripheral area | region, 4 ... Pixel, 5 ... Partition, 10 ... Organic EL element.

Claims (7)

A plurality of partitions provided linearly on the substrate;
Two types of light-emitting elements provided between the partition walls and having a plurality of light-emitting units stacked via a connection layer between the first electrode and the second electrode,
The two types of light emitting elements are:
Whereas one includes an n-type dopant and a p-type dopant in the connection layer,
The other does not contain an n-type dopant or a p-type dopant in the connection layer.   The display device according to claim 1, wherein the connection layer includes a first layer containing an electron transporting host material and a second layer containing a hole transporting host material.   The light emitting unit includes a hole injection / transport layer having hole injection or hole transportability, a light emitting layer, and an electron injection / transport layer having electron injection or electron transportability in order from the substrate side. The display device described in 1.   The display device according to claim 1, wherein the two types of light emitting elements are a blue light emitting element and a white light emitting element. Forming a plurality of partition walls extending in one direction on the substrate;
Forming a first light emitting unit between the partition walls;
Forming a connection layer having a plurality of layers on the first light emitting unit;
Forming a second light emitting unit on the connection layer,
A method for manufacturing a display device, wherein two types of light-emitting elements are formed by providing a region containing an n-type dopant and a p-type dopant and a region not containing an n-type dopant or a p-type dopant in the connection layer. In the region including and not including the n-type dopant or p-type dopant in the connection layer, the height of the partition and the positional relationship between the substrate, the first evaporation source, and the second evaporation source are expressed by the following equations 1 and The method for manufacturing a display device according to claim 5, wherein the display device is formed by vapor deposition using the partition walls as a mask.
(Equation 1)
h × (Tw / 2−t / 2) / (H−h)> 0 (1)
(Equation 2)
t−h × (Tw / 2−t / 2) / (H−h)> 0 (2)
(H: height of partition wall, T: distance between first deposition source and second deposition source, w: film formation width in substrate transport direction, t: distance between partition walls, H: distance between substrate and first deposition source distance)   7. The display device according to claim 6, wherein the region including and not including the n-type dopant or the p-type dopant in the connection layer deposits the second deposition source in an oblique direction with respect to a deposition surface of the substrate. Production method.

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