JP2015176751A - Display device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device and an electronic apparatus in which peeling of a transparent conductive film can be reduced.SOLUTION: A display device 1 includes a first electrode 31, an organic layer 33 including a luminous layer and an organic layer 33 provided on the first electrode 31, and a second electrode 34A having at least a columnar structure and provided on the second electrode 34A.

Description

  The present technology relates to an organic EL display device and an electronic apparatus that emit light using an organic electroluminescence (EL) phenomenon.

  2. Description of the Related Art In recent years, organic EL display devices using organic electroluminescence (EL) elements have attracted attention as display devices that replace liquid crystal display devices. The organic EL display device is a self-luminous type and has a characteristic of low power consumption. Furthermore, since the organic EL display device has advantages such as a wide viewing angle, excellent contrast, and high response speed, it attracts attention as a next-generation flat display device. In particular, the development of an active drive (AM) organic EL display device in which a thin film transistor (TFT) is provided for each pixel to control light emission and the degree of light emission is underway.

  A light-emitting element usually has a configuration in which a first electrode, an organic layer including a light-emitting layer made of an organic light-emitting material, and a second electrode are sequentially stacked on a substrate on which a driving transistor or the like is formed (for example, see Patent Document 1). ).

  The second electrode formed on the organic layer is formed of a transparent conductive film in, for example, a top emission type organic EL display device. This transparent conductive film is formed, for example, by a physical film formation method such as vapor deposition or sputtering, or a chemical vapor deposition method such as CVD (Chemical Vapor Deposition), and is generally formed as an amorphous film. Yes. However, when an amorphous transparent conductive film is used as the second electrode (cathode electrode), there is a problem that the transparent conductive film is easily peeled off from the organic layer by long-term driving, thereby causing a high voltage.

JP 2010-56075 A JP 2009-224152 A

As a method for solving this problem, a crystal containing indium oxide (In ₂ O ₃ ) as a main component and tin (Sn) or titanium (Ti) as an additive between an organic layer and an amorphous transparent conductive film. A transparent touch panel (display device) provided with a conductive transparent conductive film is disclosed (for example, see Patent Document 2). However, in such a display device, although the heat resistance is improved, it has been difficult to sufficiently reduce the occurrence of film peeling.

  The present technology has been made in view of such problems, and an object of the present technology is to provide a display device and an electronic apparatus that can reduce peeling of a transparent conductive film.

  The display device of the present technology includes a first electrode, an organic layer provided on the first electrode, and a second electrode provided on the organic layer having at least a columnar structure. Is.

  The electronic device of the present technology includes the display device of the present technology.

  In the display device and the electronic device of the present technology, the stress at the interface between the organic layer and the second electrode is relieved by providing the second electrode having a columnar structure on the organic layer.

In the display device and the electronic apparatus according to the present technology, since the second electrode having a columnar structure is provided on the organic layer, stress at the interface between the organic layer and the second electrode is relieved, and the organic layer of the second electrode It is possible to reduce film peeling. Thus, an electronic device with improved reliability can be provided. The effect described here is not necessarily limited,
Any effect described in the present disclosure may be used.

It is sectional drawing showing the structure of the display apparatus which concerns on one embodiment of this technique. It is a schematic diagram showing the structure of the counter electrode of the display apparatus shown in FIG. It is a characteristic view showing the voltage change amount with time of the electrically conductive film which has an amorphous structure, and the electrically conductive film which has a columnar crystal. It is a top view showing the whole structure of the display apparatus shown in FIG. FIG. 5 is a circuit diagram illustrating an example of a pixel drive circuit illustrated in FIG. 4. It is a schematic diagram for demonstrating generation | occurrence | production of film | membrane peeling. It is a schematic diagram for demonstrating an Example. It is a perspective view showing the external appearance seen from the front side of the application example 1 of the display apparatus using pixels, such as the said embodiment. It is a perspective view showing the external appearance seen from the back side of the application example 1 of the display apparatus using pixels, such as the said embodiment. 12 is a perspective view illustrating an appearance of application example 2. FIG. 14 is a perspective view illustrating an appearance of Application Example 3 viewed from the front side. FIG. 12 is a perspective view illustrating an appearance of Application Example 3 viewed from the back side. FIG. 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. FIG. 11 is a front view, a left side view, a right side view, a top view, and a bottom view of Application Example 6 in a closed state. It is the front view and side view of the application example 6 in the open state.

Hereinafter, embodiments of the present technology will be described in detail with reference to the drawings. The description will be given in the following order.
1. Embodiment (example having counter electrode having columnar structure)
1-1. Basic configuration 1-2. Overall configuration of display device 1-3. Action / Effect Application example Example

<1. Embodiment>
(1-1. Basic configuration)
FIG. 1 illustrates a cross-sectional configuration of a display device (display device 1) according to an embodiment of the present technology. In the display device 1, a display region 110 </ b> A in which a semiconductor layer 20 and a display layer 30 are stacked on a substrate 11 is provided. In the display area 110A, for example, a plurality of pixels 10 including red pixels 10R, green pixels 10G, and blue pixels 10B as sub-pixels are arranged in a matrix (see FIG. 4 for all). Each pixel 10 (10R, 10G, 10B) is provided with a red, green or blue light emitting element 2 (2R, 2G, 2B), and light emission corresponding to each pixel 10R, 10G, 10B is obtained. . The display layer 30 of the light emitting element 2 is laminated in order of the pixel electrode 31 (first electrode), the organic layer 33 including the light emitting layer, and the counter electrode 34 (second electrode) from the substrate 11 side, and is covered with a protective film 35. The counter substrate 12 is sealed with a sealing layer 36 interposed therebetween. The display device 1 is a top emission type display device in which, for example, emitted light generated in the light emitting layer is extracted from the counter electrode 34 side. In the present embodiment, the counter electrode 34 has a stacked structure of a conductive film 34A having a columnar structure and a conductive film 34B having an amorphous structure.

The substrate 11 is a high strain point glass substrate, soda glass (Na ₂ O · CaO · SiO ₂ ) substrate, borosilicate glass (Na ₂ O · B ₂ O ₃ · SiO ₂ ) substrate, forsterite (2MgO · SiO ₂ ). Examples thereof include a substrate, a lead glass (Na ₂ O · PbO · SiO ₂ ) substrate, a quartz substrate, various glass substrates having a surface formed with an insulating film, a quartz substrate, and a silicon substrate. In addition, a metal foil substrate such as aluminum (Al), nickel (Ni), copper (Cu), stainless steel or the like whose surface is insulated can be used. Further, a functional film such as a buffer layer for improving adhesion and flatness and a barrier film for improving gas barrier properties may be formed on these substrates.

  In the semiconductor layer 20, driving or writing transistors Tr1 and Tr2 and various wirings are formed, and a planarizing film 27 is provided on the transistors Tr1 and Tr2 and the wirings. The transistors Tr1 and Tr2 (hereinafter referred to as TFT 20A) may be either a top gate type or a bottom gate type. Here, a bottom gate type TFT 20A will be described as an example. In the TFT 20A, a gate electrode 21, a gate insulating film 22, a channel layer 23 for forming a channel region, and a pair of source / drain electrodes (a source electrode 24A and a drain electrode 24B) are formed in this order from the substrate 11 side. Further, an interlayer insulating film 25 (25A and 25B) and a wiring 26 are provided as a multilayer wiring layer.

  The gate electrode 21 has a role of applying a gate voltage to the channel layer 23 and controlling the carrier density in the channel layer 23 by the gate voltage. The gate electrode 21 is provided in a selective region on the substrate 11, and for example, Al, titanium (Ti), chromium (Cr), cobalt (Co), nickel (Ni), Cu, yttrium (Y), zinc (Zn). , Molybdenum (Mo), silver (Ag), tantalum (Ta), ruthenium (Ru), tungsten (W), etc. Also, two or more of these may be laminated and used.

  The gate insulating film 22 is provided between the gate electrode 21 and the channel layer 23 in a thickness range of 50 nm to 1 μm, for example. The gate insulating film 22 is preferably made of a material having a low content of hydrogen, oxygen and moisture. For example, a silicon oxide film (SiO), a silicon nitride film (SiN), a silicon oxynitride film (SiON), a hafnium oxide film (HfO), Aluminum oxide film (AlO), aluminum nitride film (AlN), tantalum oxide film (TaO), zirconium oxide film (ZrO), hafnium oxynitride film, hafnium silicon oxynitride film, aluminum oxynitride film, tantalum oxynitride film and zirconium The insulating film includes at least one of the oxynitride films. The gate insulating film 22 may have a single layer structure, or may have a laminated structure using two or more materials such as SiN and SiO.

  The channel layer 23 is provided in an island shape on the gate insulating film 22 and has a channel region at a position facing the gate electrode 21 between the source electrode 24A and the drain electrode 24B. The thickness of the channel layer 23 is, for example, 5 nm to 100 nm. The channel layer 23 is made of an oxide semiconductor containing, for example, the above-described In, Ga, Zn, and the like.

  The source electrode 24 </ b> A and the drain electrode 24 </ b> B are provided on the channel layer 23 so as to be separated from each other and are electrically connected to the channel layer 23. Examples of the material constituting the source electrode 24A and the drain electrode 24B include metal materials, semimetals, and inorganic semiconductor materials. Specifically, in addition to the materials listed in the gate electrode 21, for example, simple metals such as manganese (Mn), palladium (Pd), vanadium (V), gold (Au), and silver (Ag), or oxides thereof. , Nitrides or alloys can be used.

  The interlayer insulating film 25 (25A, 25B) is a wiring having different layers, for example, a wiring between the channel layer 23 and the source electrode 24A and the drain electrode 24B, or between the source electrode 24A and the drain electrode 24B and the wiring 26. This is to prevent a short circuit between them. Examples of the material of the interlayer insulating film 25 include insulating materials, for example, the inorganic insulating materials mentioned in the gate insulating film 22.

  The planarizing film 27 is for planarizing the surface of the substrate 11 on which the TFT 20A is formed, and has a thickness of 1 μm to 10 μm, for example. As a constituent material of the planarizing film 27, in addition to the inorganic insulating materials mentioned in the gate insulating film 22, for example, a photosensitive resin material such as polyimide, polyacrylate, epoxy, cresol novolac, or polystyrene is used. Organic materials such as those based on polyamide, polyamide and fluorine can be used.

  The display layer 30 includes the light emitting element 2 and is provided on the semiconductor layer 20. The light emitting element 2 is a light emitting element in which a pixel electrode 31, a partition wall 32 that is an interelectrode insulating film, an organic layer 33 including a light emitting layer, and a counter electrode 34 are laminated in this order from the semiconductor layer 20 side. The counter substrate 12 is bonded onto the counter electrode 34 with a protective film 35 and a sealing layer 36 interposed therebetween. The TFT 20 </ b> A and the light emitting element 2 are electrically connected via a connection hole 27 </ b> A provided in the planarizing film 27.

  The pixel electrode 31 is, for example, a metal having a high work function such as platinum (Pt), Au, Ag, Cr, W, Ni, Cu, iron (Fe), Co, Ta, or an alloy thereof (for example, silver as a main component, It is preferable to use an Ag—Pd—Cu alloy or an Al—Nd alloy containing 0.3 wt% to 1 wt% Pd and 0.3 wt% to 1 wt% Cu. Further, when a material having a small work function such as Al or an alloy containing Al is used, a hole injection layer described later can be used as an anode by improving hole injection properties using an appropriate material. Further, the pixel electrode 31 may be formed by laminating a single layer or two or more of the above metal materials.

  The partition wall 32 is for ensuring insulation between the pixel electrode 31 and the counter electrode 34 and for forming a light emitting region in a desired shape, and is made of, for example, a photosensitive resin. The partition wall 32 is provided only around the pixel electrode 31, and a region of the pixel electrode 31 exposed from the partition wall 32 is a light emitting region. The organic layer 33 and the counter electrode 34 are also provided on the partition wall 32, but light emission occurs only in the light emitting region.

  The organic layer 33 has a configuration in which, for example, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are stacked in this order from the pixel electrode 31 side. These layers may be provided as necessary. For example, when the light emitting layer is formed by adding a material having an electron transporting property, the electron transporting layer may be omitted. Further, a so-called tandem structure in which a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer are formed as one unit and two or more layers are stacked through a connection layer may be employed.

  The hole injection layer is a buffer layer for improving hole injection efficiency and preventing leakage. The hole transport layer is for increasing the efficiency of transporting holes to the light emitting layer. In the light emitting layer, recombination of electrons and holes occurs when an electric field is applied to generate light. The electron transport layer is for increasing the efficiency of electron transport to the light emitting layer. The electron injection layer is for increasing electron injection efficiency. The thicknesses of the hole injection layer (hole transport layer) and the electron injection layer (electron transport layer) are preferably substantially equal, but the supply of holes and electrons to the light-emitting layer can be kept balanced. It doesn't matter. For example, the electron injection layer (electron transport layer) may be thicker than the hole injection layer (hole transport layer). As a result, holes and electrons can be supplied to the light emitting layer without excess or deficiency, driving deterioration is suppressed, and the light emission lifetime is improved.

  The counter electrode 34 is formed of a light-transmitting material and has a structure in which a conductive film 34A having a columnar structure and a conductive film 34B having an amorphous structure are stacked in this order as shown in FIG. . In general, a conductive film having an amorphous structure, such as a conductive film 34B, is used for the counter electrode used in the organic EL display device. The conductive film having an amorphous structure is as shown in FIG. As time passes, the drive voltage increases. On the other hand, no change in voltage is observed in the conductive film having a columnar structure. Therefore, by using a conductive film having a columnar structure as the counter electrode 34, it is possible to suppress a high voltage due to long-term driving of the display device. In addition, it is possible to prevent peeling of the counter electrode 34 from the organic layer 33 by the anchor effect.

  Examples of the material of the counter electrode 34 (conductive films 34A and 34B) include metal elements such as zinc (Zn), magnesium (Mg), aluminum (Al), indium (In), and silicon (Si). It is preferable to include one or more types. Specific examples include oxides of indium and tin (ITO), InZnO (indium zinc oxide), zinc oxide (ZnO), and alloys such as Al, Mg, calcium (Ca), and Na.

  The film thickness of the conductive film 34A and the conductive film 34B is preferably, for example, from 100 nm to 1500 nm in the conductive film 34A, and is preferably, for example, from 100 nm to 500 nm in the conductive film 34B. Although the counter electrode 34 has a two-layer structure of the conductive film 34A and the conductive film 34B here, the present invention is not limited to this, and the conductive film 34B may be omitted. However, when the conductive film 34B is omitted, there is a possibility that leakage current may be generated from the gaps in the columnar structure in the conductive film 34A. Therefore, when the conductive film 34B is omitted, the thickness of the conductive film 34A is preferably 1000 nm or more. In addition, the conductive film 34A is not limited to a single layer film, and may be a stacked film including a plurality of layers. In this case, it is preferable that the film thickness increases in order from the organic layer 33 side, and the film is formed so as to have a thickness of 100 nm to 1500 nm as a whole. In addition to preventing leakage current, the conductive film 34B is formed for the purpose of improving adhesion to the protective film 35 formed in the upper layer, but a conductive film having a low resistance value is formed on the protective film 35 side. This can also serve this purpose. Specifically, for example, a layer having a low resistance value on a surface in contact with another layer (here, the organic layer 33 and the protective film 35), such as a conductive film having a low resistance value-a high conductive film-a low conductive film, The structure which arrange | positions a layer with high resistance value inside is mentioned. As a result, it is possible to prevent a short circuit and suppress the occurrence of dark spots.

The protective film 35 has a thickness of 1 to 10 μm, for example, and is formed of an insulating material such as aluminum oxide (AlO _x ), silicon oxide (SiO), or silicon oxynitride (SiON). As an insulating material other than the above, silicon nitride (SiN _x ) suitable as a protective film for the organic layer 33 may be used although the amount of hydrogen released is larger than others.

  The sealing layer 36 is for preventing moisture from entering the organic layer 33 from the outside and increasing the mechanical strength. The thickness is preferably 3 μm to 20 μm, and more preferably 5 μm. ~ 15 μm. If the thickness is less than 3 μm, foreign matter mixed during sealing may apply pressure to the light-emitting element 2 to cause dark spots such as missing pixels. When the thickness is larger than 20 μm, the distance between the light emitting layer and a color filter 37 provided on the counter substrate 12 described later is increased, and the viewing angle such as color mixing may be deteriorated. Further, since the empty surface between the sealing layer 36 and the protective film 35 has a higher light extraction efficiency when the refractive index difference is smaller, the refractive index of the sealing layer 36 is preferably, for example, 1.7 or more. Furthermore, the sealing layer 36 preferably has a transmittance of, for example, 80% or more in the display region 110A, but is not particularly limited in the peripheral region 110B (see FIG. 4).

  The color filter 37 has a red filter, a green filter, and a blue filter, and is arranged in order corresponding to each pixel 10R, 10G, 10B. Each of the red filter, the green filter, and the blue filter is, for example, rectangular and has no gap. These red filter, green filter and blue filter are each composed of a resin mixed with a pigment, and by selecting the pigment, the light transmittance in the target red, green or blue wavelength region is high, The light transmittance in the wavelength range is adjusted to be low. Note that the color filter 37 may be omitted when the light emitting elements 2R, 2G, and 2B that emit the corresponding emitted light are provided as the light emitting elements 2 in the pixels 10R, 10G, and 10B, respectively. By disposing 37, the color purity can be increased and the color gamut can be improved.

The light shielding film (black matrix 38) is constituted by, for example, a black resin film having an optical density of 1 or more mixed with a black colorant, or a thin film filter using thin film interference. Of these, a black resin film is preferable because it can be formed inexpensively and easily. The thin film filter is formed by, for example, laminating one or more thin films made of metal, metal nitride, or metal oxide, and attenuating light by utilizing interference of the thin film. Specific examples of the thin film filter include those in which chromium and chromium oxide (III) (Cr ₂ O ₃ ) are alternately laminated.

  The counter substrate 12 is located on the counter electrode 34 side of the light emitting element 2 and seals the light emitting element 2 together with an adhesive layer (not shown). The counter substrate 12 is preferably made of a material that can transmit light generated by the light emitting element 2, for example, various glass substrates or quartz substrates mentioned in the substrate 11. The counter substrate 12 is provided with a light-shielding film as, for example, a color filter 37 and a black matrix 38, so that light generated by the light-emitting element 2 is taken out and the contrast is improved.

(2-2. Manufacturing method)
The semiconductor layer 20 and the display layer 30 can be formed using, for example, a general method described below. First, a metal film is formed on the entire surface of the substrate 11 by using, for example, a sputtering method or a vacuum evaporation method. Next, the metal film is patterned by using, for example, photolithography and etching to form the gate electrode 21. Subsequently, a gate insulating film 22 and a channel layer 23 are sequentially formed on the entire surface of the substrate 11 and the gate electrode 21. Specifically, the above-described gate insulating film material, for example, a PVP (Polyvinylpyrrolidone) solution is applied over the entire surface of the substrate 11 by, for example, spin coating, and dried. Thereby, the gate insulating film 22 is formed. Next, a semiconductor is applied on the gate insulating film 22 to form a channel layer 23 on the gate insulating film 22.

  Subsequently, after an interlayer insulating film 25A is formed on the channel layer 23, a source electrode 24A and a drain electrode 24B are formed on the interlayer insulating film 25A so as to be electrically connected to the channel layer 23. Specifically, for example, a Ti film is formed by using, for example, a sputtering method. Next, the source electrode 24A and the drain electrode 24B are formed by etching using, for example, a photolithography method. Next, an interlayer insulating film 25B and a wiring 26 are sequentially formed on the source electrode 24A, the drain electrode 24B, and the interlayer insulating film 25A.

  Subsequently, after the planarization film 27 is formed on the interlayer insulating film 25B and the wiring 26, the pixel electrode 31 is disposed. Specifically, for example, after applying polyimide, the planarizing film 27 is patterned into a predetermined shape by exposure and development, and the connection hole 27A is formed and baked. Next, after a metal film is formed on the planarizing film 27 by, for example, a sputtering method, a predetermined one metal film is selectively removed by wet etching, for example, and the pixels separated into the respective pixels 10R, 10G, and 10B. The electrode 31 is formed.

Next, the organic layer 33 including the light emitting layer is formed by using, for example, a physical vapor deposition method (PVD method) such as a vacuum deposition method, various printing methods, a laser transfer method, or the like. Subsequently, of the counter electrode 34, a conductive film 34A is formed using, for example, a sputtering method. The film formation conditions are, for example, DC power density: 0.16 W / cm ² , pressure: 0.5 Pa, and O ₂ / Ar ratio: 0.17%. Thereby, the conductive film 34A having a columnar structure with a low volume resistivity (for example, 5.3E + 00Ω · cm) is obtained. Note that the volume resistivity of the conductive film 34A can be adjusted by the amount of a reactive gas (here, O ₂ ) with respect to argon (Ar). For example, by setting the O ₂ / Ar ratio to 0.43%, a conductive film having a high volume resistivity (for example, 5.5E + 05Ω · cm) can be formed. Next, after forming the conductive film 34B by using, for example, a vacuum deposition method to form the counter electrode 34, a protective film 35 made of, for example, SiNx is reacted on the counter electrode 34 with, for example, silane and ammonia gas. The film is formed using the CVD method. Further, a sealing layer 36 is formed on the protective film 35.

  Finally, an adhesive layer (not shown) is formed on the sealing layer 36, and the counter substrate 12 including the color filter 37 and the black matrix 38 is bonded to the adhesive layer. Thus, the display device 1 shown in FIG. 1 is completed.

(2-3. Overall configuration of display device)
FIG. 4 illustrates an example of a planar configuration of the entire display device 1 illustrated in FIG. The display device 1 includes a display region 110A in which a plurality of pixels 10 (10R, 10G, and 10B) are arranged in a matrix on a substrate 11, and a peripheral region 110B that is positioned around the display region 110A (outer edge side and outer peripheral side). And are provided. In the peripheral area 110B, 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 110A. FIG. 5 shows an example of the pixel driving circuit 140 (an example of a pixel circuit of the red pixel 10R, the green pixel 10G, and the blue pixel 10B). The pixel drive circuit 140 is an active drive circuit formed in the semiconductor layer 20 formed below the pixel electrode 31. The pixel driving circuit 140 includes a driving transistor Tr1 and a writing transistor Tr2, and a capacitor (holding capacity) Cs between the transistors Tr1 and Tr2. The pixel drive circuit 140 also includes the light emitting element 2 connected in series to the drive transistor Tr1 between the first power supply line (Vcc) and the second power supply line (GND). That is, a light emitting element (light emitting element 2 (2R, 2G, 2B)) is provided in each of the red pixel 10R, the green pixel 10G, and the blue pixel 10B. The drive transistor Tr1 and the write transistor Tr2 are configured by general TFTs, and the configuration may be, for example, the above-described bottom gate type or a staggered structure (top gate type) described later, and is not particularly limited.

  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 red pixel 10R, the green pixel 10G, and the blue pixel 10B. Each signal line 120A is connected to a signal line drive circuit 120, and an image signal is supplied to the source electrode of the write transistor Tr2 via the signal line drive circuit 120 to signal line 120A. Each scanning line 130A is connected to the scanning line driving circuit 130, and scanning signals are sequentially supplied from the scanning line driving circuit 130 to the gate electrode of the writing transistor Tr2 via the scanning line 130A.

  In this display device 1, a scanning signal is supplied from the scanning line driving circuit 130 to the gate electrode of the writing transistor Tr2 for each pixel 10, and an image signal is sent from the signal line driving circuit 120 via the writing transistor Tr2. It is held in the holding capacitor Cs. That is, the driving transistor Tr1 is controlled to be turned on / off in accordance with the signal held in the holding capacitor Cs, whereby the driving current Id is injected into the light emitting element 2, thereby recombining holes and electrons to emit light. Happens. This light is, for example, multiple-reflected between the pixel electrode 31 and the counter electrode 34, or the reflected light from the pixel electrode 31 and the light generated in the light emitting layer are intensified by interference, and the counter electrode 34 (conductive film 34A) And the conductive film 34B).

(1-3. Action and effect)
As described above, the electrode film (conductive film) formed on the organic layer of a general organic EL display device has an amorphous structure. In the conductive film having an amorphous structure, the conductive film easily peels from the organic layer by long-term driving. This is considered due to the surface roughness of the organic layer. For example, as shown in FIG. 6A, the organic layer (organic layer 133) has irregularities on the surface. When a film having surface contact such as a conductive film having an amorphous structure is stacked on the organic layer 133 as described above, stress concentrates on the convex portion 133A of the organic layer 133, and the conductive film is finally formed. It will be in the state (film peeling) which floated from the convex part 133A (FIG. 6 (B)). As described above, the general organic EL display device has a problem that the contact surface decreases and the drive voltage increases due to the occurrence of film floating at the interface between the organic layer 133 and the counter electrode 134 over time. .

As a method for solving this problem, for example, a crystalline conductive film (counter electrode) using In ₂ O ₃ containing an additive element such as Sn or Ti between the organic layer 133 and the amorphous conductive film 134 is used. 134). As described above, when a crystalline conductive film is formed between the organic layer 133 and the counter electrode 134, the heat resistance is improved, but the film peeling cannot be sufficiently reduced.

  In contrast, in the present embodiment, a conductive film 34A having a columnar structure is formed on the organic layer 33 as the counter electrode 34 so that the organic layer 33 and the counter electrode 34 are in point contact. As a result, as shown in FIG. 7, stress is diffused to the convex portion 33 </ b> A on the surface of the organic layer 33, so that film floating (film peeling) from the convex portion 33 </ b> A can be prevented.

  As described above, in the display device 1 of the present embodiment, the conductive film 34A having a columnar structure is used for the counter electrode 34 that is in direct contact with the organic layer 33. Therefore, at the interface between the organic layer 33 and the counter electrode 34. Stress is relieved. Thereby, film peeling of the counter electrode 34 from the organic layer 33 is suppressed, and an increase in driving voltage can be suppressed. Therefore, an electronic device with improved reliability can be provided.

  As described above, the volume resistivity of the conductive film 34A having a columnar structure can be controlled by adjusting the amount of reactive gas with respect to Ar during sputtering. The counter electrode 34 can prevent a short circuit by increasing its volume resistivity (resistance value) and suppress the occurrence of dark spots, but when the volume resistivity is high, polarization occurs in the film. In the conductive film having polarization in the film, when the organic layer 33 is charged, the charge in the organic layer 33 is relieved by the polarization component, so that film peeling is likely to occur. For this reason, the polarization performance of the conductive film 34A is controlled. Specifically, the conductive film 34A has a multilayer structure such as a film having a low volume resistivity-a high film-a low film, and a volume resistance is applied to a layer directly in contact with the organic layer 33. A conductive film with a low rate is used. This makes it possible to provide a display device with improved reliability.

<2. Application example>
The display device 1 described in the above embodiment can be suitably used, for example, as the following electronic device.

(Application example 1)
8A shows the appearance of the smartphone according to Application Example 1 from the front side, and FIG. 8B shows the back side. This smartphone includes, for example, a display unit 610 (display device 1), a non-display unit (housing) 620, and an operation unit 630. The operation unit 630 may be provided on the front surface of the non-display unit 620 as illustrated in FIG. 8A, or may be provided on the upper surface as illustrated in FIG. 8B.

(Application example 2)
FIG. 9 illustrates an appearance of a television device according to Application Example 2. This television apparatus has, for example, a video display screen unit 200 including a front panel 210 and a filter glass 220, and the video display screen unit 200 corresponds to the display device.

(Application example 3)
10A shows the appearance of the digital camera according to Application Example 3 from the front side, and FIG. 10B shows the back side. This digital camera has, for example, a flash light emitting unit 310, a display unit 320 as the display device, a menu switch 330, and a shutter button 340.

(Application example 4)
FIG. 11 illustrates an appearance of a notebook personal computer according to Application Example 4. The notebook personal computer includes, for example, a main body 410, a keyboard 420 for inputting characters and the like, and a display unit 430 as the display device.

(Application example 5)
FIG. 12 illustrates the appearance of a video camera according to Application Example 5. This video camera has, for example, a main body 510, a subject photographing lens 520 provided on the front side surface of the main body 510, a start / stop switch 530 during photographing, and a display 540 as the display device. Yes.

(Application example 6)
FIG. 13A illustrates a front view, a left side view, a right side view, a top view, and a bottom view of the cellular phone according to Application Example 6 in a closed state. FIG. 13B shows a front view and a side view of the mobile phone in an opened state. 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. . The display 740 or the sub display 750 corresponds to the display device.

<3. Example>
Next, examples of the present technology will be described. Examples 1 and 2 shown below correspond to the above embodiment. Comparative Example 1 has the same structure as that of Examples 1 and 2 except that the counter electrode is made of a conductive film having an amorphous structure.

Example 1
First, as the conductive film constituting the counter electrode 34, a conductive film 34A made of MgAlSiZnO (Experimental Examples 1-1 and 1-2) and a conductive film 134 made of MgSiZnO (Experimental Example 1-3) were formed, and their volumes The resistivity was measured. Table 1 summarizes the composition ratios and film resistance values of the elements constituting the conductive film 34A (, 134). Note that when Al is contained in the film, the crystal structure becomes a columnar structure, whereas when Al is not contained in the film, the crystal structure becomes an amorphous structure without being columnarized.

  Although Experimental Examples 1-1 and 1-2 having a columnar structure have higher volume resistivity than Experimental Example 1-3 having an amorphous structure, short-circuiting with an anode electrode (pixel electrode 31) through a foreign substance is reduced. The occurrence of dark spots can be suppressed. Further, comparing Experimental Example 1-1 and Experimental Example 1-2, the conductive film 34A having a columnar structure as in the present disclosure promotes reaction with oxygen during the process by increasing the ratio of Al to Zn. It is speculated that aluminum oxide is formed and the film longitudinal resistance can be changed.

(Example 2)
Next, an organic film corresponding to the organic layer 33 is formed, and a conductive film 34A (experimental) is formed on the organic film, for example, with a DC power of 5 kW, a deposition pressure of 0.3 P, and an O ₂ / Ar ratio of 0.15%. Examples 2-1 to 2-8) were formed, their film stress and volume resistivity were measured, and film peeling experiments at the organic film interface were conducted. Table 2 summarizes the film thickness, film stress, volume resistivity, and presence / absence of film peeling in Experimental Examples 2-1 to 2-8.

  As can be seen from Table 2, different results were obtained in Experimental Examples 2-1 and 2-2 having the same volume resistivity, for example, a volume resistivity of 5.3 Ω · cm. This is considered to be due to the fact that in Example 2-2, the film thickness was increased 10 times, so that the amount of warpage was increased due to the film stress, and film peeling occurred. Further, in the case of a volume resistivity of 550000 Ω · cm or more (Experimental Examples 2-5 to 2-7), although film peeling did not occur if the film thickness was reduced (for example, 100 nm), the film stress was small. It was found that film peeling easily occurs. This is presumably because the polarization component contributes as electrical distortion when the volume resistivity is high, but the reason is unknown. From these results, it is understood that the volume resistivity of the conductive film 34A is preferably 5.3 Ω · cm or more and less than 550000 Ω · cm. In addition, More preferably, they are 10 ohm * cm or more and 500000 ohm * cm or less. The film thickness of the conductive film 34A is 10 nm to 1500 nm when the volume resistivity is 10 Ω · cm to 500,000 Ω · cm.

  While the present technology has been described with reference to the embodiment, the present technology is not limited to the above-described embodiment and the like, and various modifications are possible. For example, the material and thickness of each layer described in the above embodiment and the like, or the film formation method and film formation conditions are not limited, and other materials and thicknesses may be used. It is good also as film | membrane conditions.

  Moreover, in the said embodiment etc., although the structure of the display apparatus 1 was mentioned concretely and demonstrated, it is not necessary to provide all the layers and you may further provide other layers.

  In addition, the effect described in this specification is an illustration to the last, and is not limited, Moreover, there may exist another effect.

In addition, this technique can also take the following structures.
(1) A display device including a first electrode, an organic layer provided on the first electrode, and a second electrode provided on the organic layer having at least a columnar structure, including a light emitting layer. .
(2) The second electrode is a first conductive film containing at least one of zinc (Zn), indium (In), magnesium (Mg), aluminum (Al), and silicon (Si). The display device described in 1.
(3) The display device according to (1) or (2), wherein the film thickness of the second electrode is not less than 100 nm and not more than 1500 nm.
(4) The display device according to (2) or (3), wherein the second electrode includes a second conductive film having an amorphous structure on the first conductive film.
(5) The display device according to any one of (2) to (4), wherein the first conductive film has a volume resistivity of 10 Ω · cm to 500,000 Ω · cm.
(6) The organic layer includes a hole injection layer having a hole injecting property to the light emitting layer and an electron injecting layer having an electron injecting property to the light emitting layer, with the light emitting layer interposed therebetween, The display device according to any one of (1) to (5), wherein the electron injection layer is made of an alkali metal or alkaline earth metal compound.
(7) The display device according to any one of (1) to (6), wherein emitted light generated in the light emitting layer is extracted from the second electrode side.
(8) A display device is provided, the display device including a first electrode, a light emitting layer, an organic layer provided on the first electrode, and provided on the organic layer having at least a columnar structure. An electronic device having a second electrode.

DESCRIPTION OF SYMBOLS 1 ... Display apparatus, 2 (2R, 2G, 2B) ... Light emitting element, 10 (10R, 10G, 10B) ... Pixel, 11 ... Substrate, 12 ... Opposite substrate, 20 ... Semiconductor layer, 20A ... TFT, 21 ... Gate electrode 22 ... gate insulating film, 23 ... channel layer, 24A ... source electrode, 24B ... drain electrode, 25 (25A, 25B) ... interlayer insulating film, 26 ... wiring, 27 ... flattening film, 27A ... connection hole, 30 ... Display layer 31... Pixel electrode 32. Partition wall 33 organic layer 34 counter electrode 34 A and 34 B conductive film 35 protective film 36 sealing layer 37 color filter 38 black matrix

Claims (8)

A first electrode;
An organic layer including a light emitting layer and provided on the first electrode;
A display device comprising: a second electrode provided on the organic layer having at least a columnar structure.   2. The display according to claim 1, wherein the second electrode is a first conductive film containing at least one of zinc (Zn), indium (In), magnesium (Mg), aluminum (Al), and silicon (Si). apparatus.   The display device according to claim 1, wherein a film thickness of the second electrode is not less than 100 nm and not more than 1500 nm.   The display device according to claim 2, wherein the second electrode includes a second conductive film having an amorphous structure on the first conductive film.   The display device according to claim 2, wherein the volume resistivity of the first conductive film is 10 Ω · cm or more and 500000 Ω · cm or less. The organic layer has a hole injection layer having a hole injecting property to the light emitting layer and an electron injecting layer having an electron injecting property to the light emitting layer, with the light emitting layer interposed therebetween,
The display device according to claim 1, wherein the electron injection layer is made of an alkali metal or alkaline earth metal compound.   The display device according to claim 1, wherein emitted light generated in the light emitting layer is extracted from the second electrode side. A display device,
The display device
A first electrode;
An organic layer including a light emitting layer and provided on the first electrode;
An electronic device having at least a columnar structure and a second electrode provided on the organic layer.

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