DISPLAY DEVICE, LIGHT-EMITTING DEVICE, AND ELECTRONIC APPARATUS

Provided is a display device capable of suppressing deterioration in reliability. A display device includes: a plurality of first electrodes; a second electrode facing the plurality of first electrodes; and an organic light-emitting layer provided between the plurality of first electrodes and the second electrode. Each of the first electrode includes: a metal layer having a main surface facing the organic light-emitting layer; and a transparent electrode covering a main surface of the metal layer and a side surface of the metal layer and containing a transparent conductive oxide. The metal layer includes: a first metal layer having a hydrogen absorption capacity; and a second metal layer provided on the first metal layer and facing the organic light-emitting layer with the transparent electrode interposed therebetween. A peripheral edge of the first metal layer is separated from the transparent electrode.

TECHNICAL FIELD

The present disclosure relates to display devices, light-emitting devices, and electronic apparatuses.

BACKGROUND ART

In recent years, organic EL (electroluminescence) display devices (hereinafter simply referred to as “display devices”) have become widespread. This display device has a structure in which an organic light-emitting layer is provided between a first electrode and a second electrode. Various configurations have been proposed for the first electrode.

For example, PTL 1 (especially see FIG. 17) discloses that the first electrode includes a metal layer and a transparent electrode, and the transparent electrode covers the main surface of the metal layer and the side surfaces of the metal layer. In addition, the metal layer includes a first metal layer and a second metal layer, and the second metal layer is provided on the first metal layer to face the organic light-emitting layer with the transparent electrode interposed therebetween.

CITATION LIST

Patent Literature

SUMMARY

Technical Problem

However, when the electrode disclosed in PTL 1 is used as the first electrode, there is a problem that the reliability of the display device is lowered.

An object of the present disclosure is to provide a display device, a light-emitting device, and an electronic apparatus capable of suppressing deterioration in reliability.

Solution to Problem

In order to solve the above problems, a first disclosure provides a display device including: a plurality of first electrodes; a second electrode facing the plurality of first electrodes; and an organic light-emitting layer provided between the plurality of first electrodes and the second electrode, wherein the first electrode includes: a metal layer having a main surface facing the organic light-emitting layer; and a transparent electrode covering a main surface of the metal layer and a side surface of the metal layer and containing a transparent conductive oxide, the metal layer includes: a first metal layer having a hydrogen absorption capacity; and a second metal layer provided on the first metal layer and facing the organic light-emitting layer with the transparent electrode interposed therebetween, and a peripheral edge of the first metal layer is separated from the transparent electrode.

A second disclosure provides a light-emitting device including: a first electrode; a second electrode facing the first electrode; and an organic light-emitting layer provided between the first electrode and the second electrode, wherein the first electrode includes: a metal layer having a main surface facing the organic light-emitting layer; and a transparent electrode covering a main surface of the metal layer and a side surface of the metal layer and containing a transparent conductive oxide, the metal layer includes: a first metal layer having a hydrogen absorption capacity; and a second metal layer provided on the first metal layer and facing the organic light-emitting layer with the transparent electrode interposed therebetween, and a peripheral edge of the first metal layer is separated from the transparent electrode.

A third disclosure provides an electronic apparatus including the display device of the first disclosure or the light-emitting device of the second disclosure.

DESCRIPTION OF EMBODIMENTS

An embodiment of the present disclosure will be described in the following order. In addition, in all drawings of the following embodiments, the same or corresponding parts are denoted by the same reference numerals.1 First embodiment1.1 Configuration of display device1.2 Manufacturing method of display device1.3 Operation and effect2 Second embodiment2.1 Configuration of display device2.2 Manufacturing method of display device2.3 Operation and effect3 Third embodiment3.1 Configuration of display device3.2 Manufacturing method of display device3.3 Operation and effect4 Modification examples5 Test example6 Application example

1 First Embodiment

[1.1 Configuration of Display Device]

FIG.1is a schematic diagram showing an example of the overall configuration of a display device10according to the first embodiment of the present disclosure. The display device10has a display region110A and a peripheral region110B provided around the peripheral edge of the display region110A. In the display region110A, a plurality of sub-pixels100R,100G, and100B are two-dimensionally arranged in a predetermined arrangement pattern such as a matrix. The pixel pitch of the sub-pixels100is preferably 10 μm or less from the viewpoint of achieving high definition of the display device10.

The sub-pixel100R displays red, the sub-pixel100G displays green, and the sub-pixel100B displays blue. In the following description, the sub-pixels100R,100G, and100B are referred to as sub-pixels100when the sub-pixels are not particularly distinguished. A combination of adjacent sub-pixels100R,100G, and100B constitutes one pixel.FIG.1shows an example in which a combination of three sub-pixels100R,100G, and100B arranged in the row direction (horizontal direction) forms one pixel.

A signal line driving circuit111and a scanning line driving circuit112, which are drivers for video display, are provided in the peripheral region110B. The signal line driving circuit111supplies a signal voltage of a video signal corresponding to luminance information supplied from a signal supply source (not shown) to the selected sub-pixel100via a signal line111A. The scanning line driving circuit112is configured by a shift register or the like that sequentially shifts (transfers) start pulses in synchronization with input clock pulses. The scanning line driving circuit112scans the sub-pixels100row by row when writing video signals to the sub-pixels100, and sequentially supplies scanning signals to the scanning lines112A.

The display device10is, for example, a microdisplay in which self-luminous elements such as OLED or Micro-OLED are formed in an array. The display device10is suitable for use as a display device for VR (Virtual Reality), MR (Mixed Reality) or AR (Augmented Reality), an electronic view finder (EVF), a small projector, or the like.

FIG.2Ais a cross-sectional view showing an example of the configuration of the display device10according to the first embodiment of the present disclosure. The display device10includes a driving substrate11A, a first insulating layer12, a plurality of first electrodes13, an organic layer14, a second electrode15, a second insulating layer16, a protective layer17, a color filter18, a filling resin layer19, and a counter substrate11B.

The display device10is an example of a light-emitting device. The display device10is a top-emission-type display device. The counter substrate11B side is the top side, and the driving substrate11A side is the bottom side. In the following description, in each layer constituting the display device10, the top surface of the display device10is referred to as a first surface, and the bottom surface of the display device10is referred to as a second surface.

The display device10includes a plurality of light-emitting elements10A. The light-emitting element10A is composed of the first electrode13, the organic layer14, and the second electrode15. The light-emitting element10A is a white OLED or white Micro-OLED (MOLED). As a method of colorization in the display device10, a method using a white OLED and the color filter18is used. However, the colorization method is not limited to this, and an RGB coloring method or the like may be used.

The driving substrate11A is a so-called backplane and drives the plurality of light-emitting elements10A. A driving circuit including sampling transistors and driving transistors for controlling driving of the plurality of light-emitting elements10A and a power supply circuit for supplying electric power to the plurality of light-emitting elements10A (both not shown) are provided on the first surface of the driving substrate11A.

The driving substrate11A may be made of, for example, glass or resin having low moisture and oxygen permeability, or may be made of a semiconductor that facilitates formation of transistors and the like. Specifically, the driving substrate11A may be a glass substrate, a semiconductor substrate, a resin substrate, or the like. Glass substrates include, for example, high strain-point glass, soda glass, borosilicate glass, forsterite, lead glass, or quartz glass. Semiconductor substrates include, for example, amorphous silicon, polycrystalline silicon, monocrystalline silicon, or the like. The resin substrate contains, for example, at least one selected from the group consisting of polymethyl methacrylate, polyvinyl alcohol, polyvinyl phenol, polyethersulfone, polyimide, polycarbonate, polyethylene terephthalate and polyethylene naphthalate.

The first insulating layer12is provided on the first surface of the driving substrate11A and covers the driving circuit, the power supply circuit, and the like. The first insulating layer12includes a plurality of contact plugs (not shown) and wirings. The contact plug connects the light-emitting element10A and the driving circuit or wirings. The contact plug connects the wirings and the driving circuit.

The first insulating layer12is made of, for example, an organic material or an inorganic material. The organic material includes, for example, at least one selected from the group consisting of polyimide, acrylic resin, and the like. The inorganic material includes, for example, at least one selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride and aluminum oxide.

The plurality of first electrodes13are provided on the first surface of the first insulating layer12. The first electrode13is the anode. When a voltage is applied between the first electrode13and the second electrode15, holes are injected into the organic layer14from the first electrode13. Adjacent first electrodes13are electrically isolated. The first electrode13is connected to a contact plug provided on the first insulating layer12. The first electrode13is connected to the driving circuit or wirings through this contact plug.

FIG.2Bis a plan view showing an example of the configuration of the first electrode13. The first electrode13includes a metal layer13A and a transparent electrode13B.

The metal layer13A functions as a reflective layer that reflects light emitted from the organic layer14. The metal layer13A has a first surface (main surface) S1and side surfaces S2, and the first surface S1faces the organic layer14. The metal layer13A includes a first metal layer13A1and a second metal layer13A2.

The first metal layer13A1is provided between the first insulating layer12and the second metal layer13A2. The first metal layer13A1improves the crystal orientation of the second metal layer13A2when forming the second metal layer13A2. As a result, the unevenness of the surface (first surface) of the second metal layer13A2can be reduced. The first metal layer13A1has hydrogen absorption capacity. The second surface of the first metal layer13A1is connected to a contact plug provided in the first insulating layer12.

The periphery of the first metal layer13A1is separated from the transparent electrode13B and is not in contact with the transparent electrode13B. In this way, it is possible to suppress the generation of moisture due to the oxidation-reduction reaction between the first metal layer13A1and the transparent electrode13B. In the in-plane direction of the driving substrate11A (that is, the in-plane direction of the display device10), the peripheral edge of the first metal layer13A1is positioned on the inner side than the peripheral edge of the second metal layer13A2. A gap13C is provided outside the side surface of the first metal layer13A1. More specifically, the gap13C is provided between the peripheral portion of the second surface of the second metal layer13A2and the first surface of the first insulating layer12. In the present specification, the peripheral portion of the second surface refers to a region having a predetermined width toward the inner side from the peripheral edge of the second surface.

An insulating layer or a metal layer may be provided in the gap13C, or the gap13C may be hollow. The hydrogen absorption capacity of the insulating layer or metal layer provided in the gap13C is lower than that of the first metal layer13A1. It is preferable that the insulating layer or metal layer provided in the gap13C does not have hydrogen absorption capacity. The constituent material of the insulating layer provided in the gap13C may be the same as or different from the insulating material forming the second insulating layer16. The constituent material of the metal layer provided in the gap13C may be the same as or different from that of the second metal layer13A2.

The first metal layer13A1contains, for example, at least one metal element selected from the group consisting of titanium (Ti) and tantalum (Ta). The first metal layer13A1may contain the at least one metal element as a constituent element of an alloy.

The second metal layer13A2is provided on the first surface of the first metal layer13A1. The second metal layer13A2faces the organic layer14with the transparent electrode13B interposed therebetween. The second metal layer13A2functions as a reflective layer that reflects light emitted from the organic layer14. The hydrogen absorption capacity of the second metal layer13A2is lower than that of the first metal layer13A1. The second metal layer13A2preferably does not have hydrogen absorption capacity.

The second metal layer13A2contains at least one metal element selected from the group consisting of, for example, aluminum (Al), silver (Ag), chromium (Cr), gold (Au), platinum (Pt), nickel (Ni), copper (Cu), molybdenum (Mo), magnesium (Mg), iron (Fe) and tungsten (W). The second metal layer13A2may contain the at least one metal element as a constituent element of an alloy. Specific examples of alloys include aluminum alloys and silver alloys. Specific examples of aluminum alloys include AlNd and AlCu. From the viewpoint of improving the reflectance, the second metal layer13A2preferably contains at least one metal element selected from the group consisting of aluminum (A1) and silver (Ag) among the above metal elements.

The transparent electrode13B is provided on the first surface (main surface) S1of the metal layer13A and covers the first surface S1of the metal layer13A and the side surface S2of the metal layer13A. The transparent electrode13B may be divided by the gap13C. The work function of the transparent electrode13B is preferably higher than the work function of the second metal layer13A2. In this case, since the transparent electrode13B is provided on the second metal layer13A2, hole injection from the first electrode13to the organic layer14can be improved. The transparent electrode13B preferably has a high transmittance from the viewpoint of improving luminous efficiency.

The transparent electrode13B contains a transparent conductive oxide (TCO). The transparent conductive oxides include at least one selected from the group consisting of, for example, transparent conductive oxides containing indium (hereinafter referred to as “indium-based transparent conductive oxides”), transparent conductive oxides containing tin (hereinafter referred to as “tin-based transparent conductive oxides”) and transparent conductive oxides containing zinc (hereinafter referred to as “zinc-based transparent conductive oxides”).

Indium-based transparent conductive oxides include, for example, indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium oxide (IGO) or indium gallium zinc oxide (IGZO) fluorine-doped indium oxide (IFO). Among these transparent conductive oxides, indium tin oxide (ITO) is particularly preferred. This is because indium tin oxide (ITO) has a particularly low hole injection barrier to the organic layer14in terms of work function, so that the driving voltage of the display device10can be particularly reduced. Tin-based transparent conductive oxides include, for example, tin oxide, antimony-doped tin oxide (ATO), or fluorine-doped tin oxide (FTO). Zinc-based transparent conductive oxides include, for example, zinc oxide, aluminum-doped zinc oxide (AZO), boron-doped zinc oxide, or gallium-doped zinc oxide (GZO).

The second electrode15is provided so as to face the first electrode13. The second electrode15is provided as a common electrode for all sub-pixels100within the display region110A. The second electrode15is the cathode. When a voltage is applied between the first electrode13and the second electrode15, electrons are injected from the second electrode15into the organic layer14. The second electrode15is a transparent electrode that is transparent to light generated in the organic layer14. Here, the transparent electrode includes a semi-transmissive reflective layer. The second electrode15is preferably made of a material having as high transmittance as possible and a small work function, in order to increase the luminous efficiency.

The second electrode15is composed of, for example, at least one layer of a metal layer and a transparent electrode. More specifically, the second electrode15is composed of a single layer film of a metal layer or a transparent electrode, or a laminated film of a metal layer and a transparent electrode. When the second electrode15is composed of a laminated film, the metal layer may be provided on the organic layer14side, and the transparent electrode may be provided on the organic layer14side. However, from the viewpoint of placing a layer with a low work function adjacent to the organic layer14, the metal layer is preferably provided on the organic layer14side.

The metal layer contains, for example, at least one metal element selected from the group consisting of magnesium (Mg), aluminum (Al), silver (Ag), calcium (Ca) and sodium (Na). The metal layer may contain the at least one metal element as a constituent element of an alloy. Specific examples of alloys include MgAg alloys, MgAl alloys, AlLi alloys, and the like. A transparent electrode contains a transparent conductive oxide. Examples of the transparent conductive oxide include the same materials as those of the transparent electrode13B described above.

The organic layer14is provided between the plurality of first electrodes13and the second electrode15. The organic layer14is provided as an organic layer common to all sub-pixels100within the display region110A. The organic layer14is configured to emit white light.

The organic layer14has a configuration in which a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer are laminated in this order from the first electrode13toward the second electrode15. The configuration of the organic layer14is not limited to this, and layers other than the light-emitting layer are provided as necessary.

The hole injection layer is a buffer layer for increasing the efficiency of hole injection into the light-emitting layer and suppressing leakage. The hole transport layer is provided for increasing the efficiency of transporting holes to the light-emitting layer. In the light-emitting layer, the application of an electric field causes recombination of electrons and holes, thereby generating light. The light-emitting layer is an organic light-emitting layer containing an organic light-emitting material. The electron transport layer is provided for increasing the efficiency of transporting electrons to the light-emitting layer. An electron injection layer may be provided between the electron transport layer and the second electrode15. This electron injection layer is for enhancing the electron injection efficiency.

The second insulating layer16is provided on the first surface of the first insulating layer12. The second insulating layer16is provided between the adjacent first electrodes13and electrically isolates the adjacent first electrodes13. The second insulating layer16has a plurality of openings16A. The plurality of openings16A are provided so as to correspond to the respective sub-pixels100. The opening16A exposes the first surface of the first electrode13(the surface facing the second electrode15). The first electrode13and the organic layer14are in contact with each other through the opening16A. One opening16A may be provided for one first electrode13, or two openings16A may be provided for one first electrode13(seeFIG.2B).

The second insulating layer16may cover a region extending from the peripheral portion of the first surface of the first electrode13to the side surface (end surface) of the first electrode13. In the present specification, the peripheral portion of the first surface refers to a region having a predetermined width toward the inner side from the peripheral edge of the first surface. Part of the insulating material forming the second insulating layer16may enter the gap13C provided between the second insulating layer16and the second metal layer13A2.

In the in-plane direction of the driving substrate11A (that is, the in-plane direction of the display device10), the peripheral edge of the first metal layer13A1is preferably positioned on the outer side of the opening16A of the second insulating layer16. As a result, deterioration of the crystal orientation of the portion of the second metal layer13A2corresponding to the opening16A can be suppressed. Therefore, the unevenness of the portion of the first surface of the second metal layer13A2exposed from the opening16A (that is, the portion of the first surface of the second metal layer13A2that contacts the organic layer14) can be reduced.

As a constituent material of the second insulating layer16, the same material as that of the above-described first insulating layer12can be exemplified.

The protective layer17is provided on the first surface of the second electrode15and covers the plurality of light-emitting elements10A. The protective layer17shields the light-emitting element10A from the outside air, and suppresses the intrusion of moisture from the external environment into the light-emitting element10A. Moreover, when the second electrode15is composed of a metal layer, the protective layer17may have a function of suppressing oxidation of this metal layer.

The protective layer17contains, for example, an inorganic material with low hygroscopicity. The inorganic material includes, for example, at least one of silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiNO), titanium oxide (TiO) and aluminum oxide (AlO). The protective layer17may have a single-layer structure, but may have a multi-layer structure when the thickness of the protective layer17is increased. This is for alleviating the internal stress in the protective layer17. The protective layer17may be made of polymer resin. The polymer resin includes at least one selected from the group consisting of thermosetting resins, ultraviolet curing resins, and the like.

The color filter18is provided on the first surface of the protective layer17. The color filter18is, for example, an on-chip color filter (OCCF). The color filter18includes, for example, a red filter, a green filter and a blue filter. The red filter, green filter, and blue filter are provided to face the light-emitting element10A for the red sub-pixel100R, the light-emitting element10A for the green sub-pixel100G, and the light-emitting element10A for the blue sub-pixel100B, respectively. The sub-pixels100R,100G, and100B are thus configured.

White light emitted from each light-emitting element10A in the sub-pixels100R,100G, and100B is transmitted through the red, green, and blue filters, respectively, so that the red, green, and blue lights are emitted from the display surface. A light shielding layer (not shown) may be provided in the region between the color filters of each color, that is, between the sub-pixels. The color filters18are not limited to on-chip color filters, and may be provided on one main surface of the counter substrate11B.

The filling resin layer19is provided between the color filter18and the counter substrate11B. The filling resin layer19functions as an adhesive layer that bonds the color filter18and the counter substrate11B. The filling resin layer19contains, for example, at least one selected from the group consisting of thermosetting resins, ultraviolet curing resins, and the like.

The counter substrate11B is provided to face the driving substrate11A. More specifically, the counter substrate11B is provided such that the second surface of the counter substrate11B faces the first surface of the driving substrate11A. The counter substrate11B and the filling resin layer19seal the light-emitting element10A, the color filter18, and the like. The counter substrate11B is made of a material such as glass that is transparent to each color light emitted from the color filter18.

[1.2 Manufacturing Method of Display Device]

An example of a method for manufacturing the display device10according to the first embodiment of the present disclosure will be described below with reference toFIGS.3A to3CandFIGS.4A to4C.

First, a driving circuit, a power supply circuit, and the like are formed on the first surface of the driving substrate11A using, for example, thin film formation technology, photolithography technology, and etching technology. Next, the first insulating layer12is formed on the first surface of the driving substrate11A so as to cover the driving circuit, the power supply circuit, and the like by, for example, a CVD (Chemical Vapor Deposition) method. At this time, a plurality of contact plugs, a plurality of wirings, and the like are formed in the first insulating layer12.

Next, the first metal layer13A1is formed on the first surface of the first insulating layer12by, for example, sputtering. Subsequently, the second metal layer13A2is formed on the first surface of the first metal layer13A1by, for example, sputtering. Next, after forming a resist mask having a predetermined pattern on the first surface of the second metal layer13A2, the first metal layer13A1and the second metal layer13A2are patterned by dry-etching the first metal layer13A1and the second metal layer13A2through the resist mask (seeFIG.3A). In this way, a plurality of patterned metal layers13A are formed on the first surface of the first insulating layer12.

Next, by wet-etching, for example, the peripheral edge of the first metal layer13A1is recessed from the peripheral edge of the first metal layer13A1toward the center. As a result, the peripheral edge of the first metal layer13A1is positioned on the inner side than the peripheral edge of the second metal layer13A2in the in-plane direction of the driving substrate11A, and the gap13C is formed between the peripheral portion of the second surface of the second metal layer13A2and the first surface of the first insulating layer12(seeFIG.3B). As a chemical solution for wet etching, it is preferable to use a solution that provides a large etching selectivity of the first metal layer13A1to the second metal layer13A2((etching rate of the first metal layer13A1)/(etching rate of the second metal layer13A2)) and can selectively etch the first metal layer13A1. As a chemical solution for wet etching, one that does not corrode the second metal layer13A2is preferable.

Next, the transparent electrode13B is formed on the first surface of the first insulating layer12so as to cover the plurality of metal layers13A by sputtering, for example. At this time, the transparent electrode13B may be divided by the gap13C. A structure in which the transparent electrode13B covers the entire metal layer13A (that is, a structure in which the side surface S2of the metal layer13A as well as the first surface S1of each metal layer13A are covered) is preferable. In this way, it is possible to suppress dissolution of each metal layer13A with a developer when forming a resist mask for the transparent electrode13B. Next, after forming a resist mask having a predetermined pattern on the first surface of the transparent electrode13B, the transparent electrode13B is patterned by dry-etching the transparent electrode13B through the resist mask. In this way, a plurality of first electrodes13are formed on the first surface of the first insulating layer12(seeFIG.3C).

Next, the second insulating layer16is formed on the first surface of the first insulating layer12so as to cover the plurality of first electrodes13by, for example, CVD. Thereafter, after forming a resist mask having a predetermined pattern on the first surface of the second insulating layer16, a plurality of openings16A is formed in the second insulating layer16by etching the second insulating layer16through the resist mask (seeFIG.4A).

Next, the organic layer14is formed by laminating a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer in this order on the first surface of the first electrode13and the first surface of the second insulating layer16by vapor deposition, for example (seeFIG.4B). Next, the second electrode15is formed on the first surface of the organic layer14by vapor deposition or sputtering, for example. In this way, a plurality of light-emitting elements10A are formed on the first surface of the first insulating layer12(seeFIG.4C).

Next, after forming a protective layer17on the first surface of the second electrode15by, for example, CVD or vapor deposition, a color filter18is formed on the first surface of the protective layer17by, for example, photolithography. A planarization layer may be formed above, below, or both above and below the color filter18in order to planarize the step of the protective layer17and the step due to the film thickness difference of the color filter18itself. Next, after covering the color filter18with the filling resin layer19using, for example, the ODF (One Drop Fill) method, the counter substrate11B is placed on the filling resin layer19. Next, for example, by applying heat to the filling resin layer19or irradiating the filling resin layer19with ultraviolet rays to harden the filling resin layer19, the driving substrate11A and the counter substrate11B are bonded together with the filling resin layer19interposed therebetween. In this way, the display device10is sealed. In this way, the display device10shown inFIGS.1and2Ais obtained.

[1.3 Operation and Effect]

In order to facilitate understanding of the operation and effect of the display device10according to the first embodiment, the operation and effect of the display device10will be described by comparing the configuration of the display device410according to the reference example with the configuration of the display device10according to the first embodiment.

FIG.5is a cross-sectional view showing the configuration of a display device410according to a reference example. In the display device410according to the reference example, a first electrode413includes a metal layer413A and a transparent electrode413B. A peripheral edge of a first metal layer413A1included in the metal layer413A is in contact with the transparent electrode413B. Since the constituent material of the first metal layer413A1has a hydrogen absorption capacity, hydrogen usually remains in the first metal layer413A1during and after the display device410is manufactured. Therefore, when the first metal layer413A1is in contact with the transparent electrode413B as described above, an oxidation-reduction reaction occurs between the first metal layer413A1and the transparent electrode413B at the contact portion, and moisture is generated. When the generated moisture permeates through the second insulating layer16and reaches the organic layer14as indicated by the arrows inFIG.5, the organic layer14deteriorates. Therefore, the reliability of the display device410is lowered. Moisture generation due to oxidation-reduction reaction occurs, for example, when the transparent electrode413B is formed in the manufacturing process of the display device410and when the first electrode413is heated in the manufacturing process of the display device410.

It is thought that the effect of the moisture generation will become remarkable because the ratio of the contact area (the contact area between the first metal layer413A1and the transparent electrode413B) to the light-emitting region increases when pixels are made to have high definition (for example, the sub-pixel pitch is made to be 10 μm or less).

In addition, abnormal growth of the transparent electrode413B occurs at the contact portion between the first metal layer413A1and the transparent electrode413B. Abnormal light emission occurs at a location where such abnormal growth occurs. The abnormal growth is considered to be caused by indium agglomeration.

In contrast, in the display device10according to the first embodiment, the peripheral edge of the first metal layer13A1included in the metal layer13A is separated from the transparent electrode13B. In this way, it is possible to suppress the generation of moisture due to the oxidation-reduction reaction between the first metal layer13A1and the transparent electrode13B. Therefore, deterioration in reliability of the organic layer14due to moisture can be suppressed. Therefore, deterioration in reliability of the display device10can be suppressed.

Moreover, it is possible to suppress the occurrence of abnormal growth of the transparent electrode13B at the contact portion between the first metal layer13A1and the transparent electrode13B. Therefore, it is possible to suppress the occurrence of abnormal light emission.

2 Second Embodiment

[2.1 Configuration of Display Device]

FIG.6is a cross-sectional view showing an example of the configuration of a display device20according to a second embodiment of the present disclosure. The display device20includes a first electrode23instead of the first electrode13(seeFIG.2A) in the first embodiment. The display device20also includes a plurality of sidewalls21. The first electrode23, the organic layer14, and the second electrode15constitute a light-emitting element20A. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted.

The first electrode23includes a metal layer23A and a transparent electrode23B. The metal layer23A includes a first metal layer23A1and a second metal layer13A2. The peripheral edge of the first metal layer23A1and the peripheral edge of the second metal layer13A2are aligned in the thickness direction of the first electrode23. However, the configuration of the metal layer23A is not limited to this, and the peripheral edge of the first metal layer23A1may be positioned on the inner side of the peripheral edge of the second metal layer13A2in the in-plane direction of the driving substrate11A. Alternatively, the peripheral edge of the first metal layer23A1may be positioned on the outer side of the peripheral edge of the second metal layer13A2. The transparent electrode23B covers the first surface S1and the sidewalls21of the metal layer23A.

The plurality of sidewalls21are provided on the first surface of the first insulating layer12. The sidewall21surrounds the metal layer23A and covers the side surface S2of the metal layer23A.FIG.6shows an example in which the sidewall21covers the entire side surface S2of the metal layer23A, but it is sufficient if it covers at least the side surface of the first metal layer13A1. The sidewall21is provided between the side surface S2of the metal layer23A and the transparent electrode23B.

In order to suppress the generation of moisture due to the oxidation-reduction reaction, the sidewalls21preferably have lower hydrogen absorption capacity than the first metal layer13A1, and more preferably, the sidewalls21do not have the hydrogen absorption capacity.

The sidewalls21contain, for example, at least one selected from the group consisting of metals, insulating materials, and the like. As the metal, the same material as that of the second metal layer13A2can be exemplified. As the insulating material, the same material as that of the first insulating layer12can be exemplified.

[2.2 Manufacturing Method of Display Device]

An example of a method for manufacturing the display device20according to the second embodiment of the present disclosure will be described below with reference toFIGS.7A to7C.

First, the steps up to the etching of the first metal layer23A1and the second metal layer13A2are performed in the same manner as in the method of manufacturing the display device10according to the first embodiment. In this way, a plurality of patterned metal layers23A are formed on the first surface of the first insulating layer12.

Next, an insulating layer21A is formed on the first surface of the first insulating layer12so as to cover the plurality of metal layers23A by, for example, CVD (seeFIG.7A). After that, by etching back the insulating layer21A, the sidewall21is formed on the side surface S2of each metal layer23A (seeFIG.7B). By forming the sidewall21on the side surface S2of each metal layer23A in this way, it is possible to suppress contact between the peripheral edge of the first metal layer23A1and the transparent electrode23B in a later step.

Next, a transparent electrode23B is formed on the first surface of the first insulating layer12so as to cover the plurality of metal layers23A and the plurality of sidewalls21by sputtering, for example. Next, after forming a resist mask having a predetermined pattern on the first surface of the transparent electrode23B, the transparent electrode23B is patterned by dry-etching the transparent electrode23B through the resist mask. In this way, a plurality of first electrodes23is formed on the first surface of the first insulating layer12(seeFIG.7C).

Subsequent steps are performed in the same manner as in the manufacturing method of the display device10of the first embodiment. In this way, the display device20shown inFIG.6is obtained.

In the manufacturing method described above, the sidewalls21are formed from the insulating layer21A. However, the manufacturing method of the display device20is not limited to this. A metal layer may be used instead of the insulating layer21A, and the sidewalls21may be formed from the metal layer.

[2.3 Operation and Effect]

In the display device20according to the second embodiment, the sidewall21covers the side surface S2of the metal layer23A, and the sidewall21is sandwiched between the peripheral edge of the first metal layer23A1and the transparent electrode23B. As a result, since the peripheral edge of the first metal layer23A1can be separated from the transparent electrode23B, deterioration in reliability of the display device20can be suppressed. The occurrence of abnormal light emission can be suppressed.

[3.1 Configuration of Display Device]

FIG.8is a cross-sectional view showing an example of the configuration of a display device30according to a third embodiment of the present disclosure. The display device30includes a first electrode33instead of the first electrode13(seeFIG.2A) in the first embodiment. The first electrode33, the organic layer14, and the second electrode15constitute a light-emitting element30A. In the third embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted.

The first electrode23includes a metal layer33A and a transparent electrode33B. The metal layer33A includes a first metal layer13A1and a second metal layer33A2. The peripheral edge of the second metal layer33A2is positioned on the outer side than the peripheral edge of the first metal layer13A1. The second metal layer33A2covers the side surface of the first metal layer13A1. The transparent electrode33B covers the first surface (main surface) S1of the second metal layer33A2and the side surface S2of the second metal layer33A2.

[3.2 Manufacturing Method of Display Device]

An example of a method for manufacturing the display device30according to the third embodiment of the present disclosure will be described below with reference toFIGS.9A to9C.

First, the steps up to the formation of the first insulating layer12are performed in the same manner as in the method of manufacturing the display device10according to the first embodiment. Next, a first metal layer13A1is formed on the first surface of the first insulating layer12. Next, after forming a resist mask having a predetermined pattern on the first surface of the first metal layer13A1, the first metal layer13A1is patterned by dry-etching the first metal layer13A1through the resist mask. In this way, a plurality of first metal layers13A1are formed on the first surface of the first insulating layer12(seeFIG.9A).

Next, a second metal layer33A2is formed on the first surface of the first insulating layer12so as to cover the plurality of first metal layers13A1by sputtering. Next, after forming a resist mask having a predetermined pattern on the first surface of the second metal layer33A2, the second metal layer33A2is patterned by dry-etching the second metal layer33A2through the resist mask. In this way, a plurality of metal layers33A are formed on the first surface of the first insulating layer12(seeFIG.9B).

Next, a transparent electrode33B is formed on the first surface of the first insulating layer12so as to cover the plurality of metal layers33A by, for example, sputtering. Next, after forming a resist mask having a predetermined pattern on the first surface of the transparent electrode33B, the transparent electrode33B is patterned by dry-etching the transparent electrode33B through the resist mask. In this way, a plurality of first electrodes33are formed on the first surface of the first insulating layer12(seeFIG.9C).

Subsequent steps are performed in the same manner as in the manufacturing method of the display device10of the first embodiment. As described above, the display device30shown inFIG.8is obtained.

[3.3 Operation and Effect]

In the display device30according to the third embodiment, the peripheral edge of the second metal layer33A2is positioned on the outer side than the peripheral edge of the first metal layer13A1, and the second metal layer33A2covers the side surface of the first metal layer13A1. As a result, part of the second metal layer33A2can be interposed between the peripheral edge of the first metal layer13A1and the transparent electrode33B, and the peripheral edge of the first metal layer13A1can be separated from the transparent electrode33B. Therefore, deterioration in reliability of the display device30can be suppressed. The occurrence of abnormal light emission can be suppressed.

4 Modification Examples

Modification Example 1

In the first embodiment, the configuration in which the transparent electrode13B is divided by the gap13C (seeFIG.2A) has been described, but the transparent electrode13B may cover the gap13C as shown inFIG.10. In this case, the gap13C may be hollow, or an insulating layer or a metal layer may be provided in the gap13C. Note thatFIG.10shows an example in which the gap13C is hollow.

Modification Example 2

In the first to third embodiments, an example in which the present disclosure is applied to a display device has been described, but the present disclosure is not limited to this, and can be applied to light-emitting devices other than display devices. Examples of light-emitting devices other than display devices include, but are not limited to, lighting devices. In this case, the number of light-emitting elements included in the light-emitting device such as the lighting device may be plural or singular.

5 Test Example

As described below, samples were prepared by forming a transparent conductive oxide layer (ITO layer, IZO layer, IGZO layer) on a Ti layer, and occurrence of moisture due to oxidation-reduction reaction was evaluated using these prepared samples.

Sample 1-1 was obtained by forming an ITO layer on a hydrogen-absorbed Ti layer by a sputtering method.

Sample 1-2 was obtained by forming an IZO layer on a hydrogen-absorbed Ti layer by a sputtering method.

Sample 1-3 was obtained by forming an IGZO layer on a hydrogen-absorbed Ti layer by a sputtering method.

A hydrogen-absorbed Ti layer was used as sample 1-4.

Thermal desorption of moisture from samples 1-1 to 1-4 was measured by TDS (Thermal Desorption Spectrometry).FIG.11Ashows the TDS spectra resulting from this measurement.

It can be seen fromFIG.11Athat when the samples 1-1 to 1-3 in which the metal layer in which hydrogen is absorbed and the transparent conductive oxide layer (transparent electrode) are in contact are heated, moisture is generated.

As described below, samples were prepared by forming a thin film on a Si substrate, and the desorption amount of hydrogen was evaluated using these prepared samples.

Sample 2-1 was obtained by forming a Ti layer on a Si substrate by a sputtering method.

Sample 2-2 was obtained by forming an AlO layer on a Si substrate by an ALD (Atomic Layer Deposition) method.

Sample 2-3 was obtained by forming a SiCO layer on a Si substrate by plasma CVD.

Sample 2-4 was obtained by forming an AlO layer on a Si substrate by a sputtering method.

The desorption amount of hydrogen from samples 2-1 to 2-4 was measured by TDS.FIG.11Bshows the TDS spectra resulting from this measurement.

It can be seen fromFIG.11Bthat the amount of desorption of hydrogen from the Ti layer is the largest among the evaluation thin films. From this result, it is presumed that the amount of moisture generated is particularly large when the Ti layer and the transparent conductive oxide layer (transparent electrode) are in contact with each other.

6 Application Example

The display devices10,20, and30according to the above-described first to third embodiments and modification examples thereof can be used in various electronic apparatuses. The display devices10,20and30are incorporated into various electronic apparatuses as modules as shown inFIG.12, for example. In particular, the display devices are suitable for electronic viewfinders of video cameras or single-lens reflex cameras, head-mounted displays, or the like, which require high resolution and are used in close proximity to the eyes. This module has an exposed region210that is not covered with the counter substrate11B or the like on one short side of the driving substrate11A, and wiring of the signal line driving circuit111and the scanning line driving circuit112is extended so that an external connection terminal (not shown) is formed in this region210. A flexible printed circuit (FPC)220for signal input/output may be connected to the external connection terminal.

Specific Example 1

FIGS.13A and13Bshow an example of the appearance of a digital still camera310. This digital still camera310is an interchangeable single-lens reflex-type camera, and has an interchangeable photographing lens unit (interchangeable lens)312in approximately the center of the front surface of a camera main body (camera body)311, and has a grip portion313for a photographer to hold on the left side of the front surface.

A monitor314is provided at a position shifted to the left from the center of the rear side of the camera main unit311. On the monitor314, an electronic viewfinder (eyepiece window)315is provided. Viewing through the electronic viewfinder315allows the photographer to visually recognize an optical subject image guided from the photographing lens unit312and determine the composition. As the electronic viewfinder315, any one of the display devices10,20, and30can be used.

Specific Example 2

FIG.14shows an example of the appearance of a head-mounted display320. The head-mounted display320has, for example, ear hooks322on both sides of an eyeglass-shaped display unit321to be worn on the user's head. As the display unit321, any one of the display devices10,20, and30can be used.

Specific Example 3

FIG.15shows an example of the appearance of a television device330. This television device330has, for example, a video display screen portion331including a front panel332and a filter glass333. The video display screen portion331is configured by any one of the display devices10,20, and30.

Although the first to third embodiments of the present disclosure and the modification examples thereof have been specifically described above, the present disclosure is not limited to the above-described first to third embodiments and the modification examples thereof, and various modifications based on the technical idea of the present disclosure are possible.

For example, the configurations, methods, processes, shapes, materials, numerical values, and the like given in the above-described first to third embodiments and the modification examples thereof are merely examples, and different configurations, methods, processes, shapes, materials, numerical values, and the like may be used, if necessary.

In addition, the configurations, methods, processes, shapes, materials, numerical values, and the like in the first to third embodiments and the modification examples thereof described above can be combined with each other without departing from the gist of the present disclosure.

The materials exemplified in the above-described first to third embodiments and the modification examples thereof may be used singly or in combination of two or more unless otherwise specified.

In addition, the present disclosure may have the following constitutions.

A display device including: a plurality of first electrodes; a second electrode facing the plurality of first electrodes; and an organic light-emitting layer provided between the plurality of first electrodes and the second electrode, wherein each of the first electrode includes: a metal layer having a main surface facing the organic light-emitting layer; and a transparent electrode covering a main surface of the metal layer and a side surface of the metal layer and containing a transparent conductive oxide, the metal layer includes: a first metal layer having a hydrogen absorption capacity; and a second metal layer provided on the first metal layer and facing the organic light-emitting layer with the transparent electrode interposed therebetween, and a peripheral edge of the first metal layer is separated from the transparent electrode.

(2) The display device according to (1), wherein the first metal layer contains at least one selected from the group consisting of titanium (Ti) and tantalum (Ta).

(3) The display device according to (1) or (2), wherein a peripheral edge of the first metal layer is positioned on an inner side of a peripheral edge of the second metal layer.

(4) The display device according to (3), wherein a gap is provided on an outer side of a side surface of the first metal layer.

(5) The display device according to (4), wherein an insulating layer or a metal layer is provided in the gap.

(6) The display device according to (4), wherein the gap is hollow.

(7) The display device according to any one of (1) to (3), wherein the second metal layer covers a side surface of the first metal layer.

(8) The display device according to any one of (1) to (7), further including a sidewall provided between a side surface of the metal layer and the transparent electrode.

(9) The display device according to (8), wherein the sidewall has lower hydrogen absorption capacity than the first metal layer.

(10) The display device according to (8), wherein the sidewall does not have hydrogen absorption capacity.

(11) The display device according to any one of (8) to (10), wherein the sidewall contains at least one selected from the group consisting of metals and insulating materials.

(12) The display device according to any one of (1) to (11), further including an insulating layer having a plurality of openings, wherein the first electrode is exposed from the opening, and a peripheral edge of the first metal layer is positioned on an outer side of a peripheral edge of the opening.

(13) The display device according to any one of (1) to (12), wherein the second metal layer contains at least one selected from the group consisting of aluminum (Al) and silver (Ag).

(14) The display device according to any one of (1) to (13), wherein the transparent conductive oxide contains at least one selected from the group consisting of a transparent conductive oxide containing indium, a transparent conductive oxide containing tin, and a transparent conductive oxide containing zinc.

(15) A light-emitting device including: a first electrode; a second electrode facing the first electrode; and an organic light-emitting layer provided between the first electrode and the second electrode, wherein the first electrode includes: a metal layer having a main surface facing the organic light-emitting layer; and a transparent electrode covering a main surface of the metal layer and a side surface of the metal layer and containing a transparent conductive oxide, the metal layer includes: a first metal layer having a hydrogen absorption capacity; and a second metal layer provided on the first metal layer and facing the organic light-emitting layer with the transparent electrode interposed therebetween, and a peripheral edge of the first metal layer is separated from the transparent electrode.

(16) An electronic apparatus including the display device according to any one of (1) to (14).

REFERENCE SIGNS LIST