JP2015050051A - Top-emission type organic electroluminescent display device - Google Patents

Abstract

A main object of the present invention is to provide a highly reliable organic EL display device with less luminance unevenness, good display characteristics, and high reliability. The present invention includes a substrate, a pixel electrode formed on the substrate, an auxiliary electrode formed on the substrate and disposed between the adjacent pixel electrodes, and formed on the substrate. An insulating layer disposed between the adjacent pixel electrodes and between the pixel electrode and the auxiliary electrode, an organic EL layer formed on the pixel electrode and having a plurality of organic layers including a light emitting layer, and the organic EL A transparent electrode layer formed on the layer, at least one of the organic layers constituting the organic EL layer has a stripe-shaped opening on the auxiliary electrode, and the transparent electrode layer is the auxiliary electrode And a top emission type organic EL display device characterized in that the interval between the openings of the organic layer is within a range of 1 mm or more and 100 mm or less. To do. [Selection] Figure 1

Description

  The present invention relates to a top emission type organic electroluminescence display device having an auxiliary electrode.

  The organic electroluminescence display device has high visibility due to self-coloring, it is an all-solid-state display unlike a liquid crystal display device, so it has excellent impact resistance, has a fast response speed, is less affected by temperature changes, In addition, it has attracted attention because of its advantages such as a large viewing angle, and research and development and commercialization are being promoted as flat panel displays following liquid crystal display devices and plasma displays. Hereinafter, electroluminescence may be abbreviated as EL.

  There are passive matrix driving and active matrix driving as driving methods of the organic EL display device, but in the case of a large display, active matrix driving is advantageous from the viewpoint that driving by a low voltage is possible. Here, active matrix driving refers to a system in which a circuit such as a TFT is formed on an organic EL element substrate on which an organic EL element is formed, and the circuit is driven by a circuit such as a TFT.

  Organic EL display devices include a bottom emission type in which light is extracted from the organic EL element substrate side, and a top emission type in which light is extracted from the counter substrate side disposed to face the organic EL element substrate. Here, in the case of an organic EL display device driven by an active matrix, in the bottom emission type, the aperture ratio is limited by a circuit such as a TFT formed on the organic EL element substrate which is a light extraction surface, and the light extraction efficiency is reduced. There is a problem that it ends up. On the other hand, in the top emission type, since light is extracted from the counter substrate, higher light extraction efficiency can be obtained than in the bottom emission type.

  In the organic EL display device, the electrode layer on the light extraction side is a transparent electrode layer. Generally, a transparent electrode layer has a higher resistance than an electrode layer made of a metal such as Al or Cu. For this reason, a voltage drop occurs due to the resistance of the transparent electrode layer, and as a result, the occurrence of so-called luminance unevenness, in which the luminance uniformity of the organic EL display device is lowered, is a problem. In addition, since the resistance increases as the area of the transparent electrode layer increases, the problem of uneven brightness becomes significant in the case of a large display.

  For the above-described problem, a method is known in which a voltage drop is suppressed by forming a low-resistance auxiliary electrode and electrically connecting the auxiliary electrode to a transparent electrode layer. In general, the auxiliary electrode is patterned by performing a wet process etching after forming a metal layer. Therefore, in the top emission type organic EL display device, when the auxiliary electrode is formed on the organic EL layer or the transparent electrode layer, the organic EL layer or the transparent electrode layer is eroded by the etching solution used when forming the auxiliary electrode. There was a problem of being. Therefore, for example, as described in Patent Documents 1 to 4, a method of forming an auxiliary electrode under the organic EL layer has been proposed.

  However, when the auxiliary electrode is formed below the organic EL layer, when at least one organic layer constituting the organic EL layer is formed on the entire surface of the substrate on which a circuit such as a TFT and the auxiliary electrode are formed. However, the organic layer hinders electrical connection between the auxiliary electrode and the transparent electrode layer.

  Therefore, for example, Patent Documents 1 to 4 propose a method of forming an opening by removing the organic layer on the auxiliary electrode by laser ablation in order to electrically connect the auxiliary electrode and the transparent electrode layer. Yes. However, this method has a problem in that the organic layer material is scattered during laser irradiation, the pixel region is contaminated, and display characteristics are deteriorated.

Japanese Patent No. 4959119 Special table 2010-538440 gazette Japanese Patent No. 4340982 Japanese Patent No. 4545780

  In the above organic layer removal method by laser ablation, it is usual to form an opening for each pixel. For example, an opening is provided in a dot shape for each pixel, or an opening in a stripe shape along the pixel. Has been proposed. When the organic layer is removed in the form of stripes, the scattering of the material of the organic layer at the time of laser irradiation is greater than when the organic layer is removed in the form of dots. Therefore, in order to reduce scattering of the material of the organic layer, it is conceivable to reduce the density of the openings when the organic layer is removed in a stripe shape. However, if the density of the openings in the organic layer is lowered, the effect of suppressing the voltage drop by the auxiliary electrode may not be obtained. In addition, when the density of the openings in the organic layer is low, current may concentrate in the openings where the transparent electrode layer and the auxiliary electrode are electrically connected, resulting in disconnection or heat generation.

  The present invention has been made in view of the above problems, and has as its main object to provide a highly reliable organic EL display device with less luminance unevenness, good display characteristics, and high reliability.

  As a result of diligent investigations to solve the above problems, the present inventors have found that in order to improve all of luminance unevenness due to voltage drop, disconnection due to current concentration, and scattering of the organic layer material during laser ablation, The inventors have found that it is effective to set the interval between the openings of the layers within a predetermined range, and have completed the present invention.

  That is, the present invention provides a substrate, a pixel electrode formed on the substrate, an auxiliary electrode formed on the substrate and disposed between the adjacent pixel electrodes, and formed on the substrate and adjacent thereto. An insulating layer disposed between the pixel electrodes and between the pixel electrode and the auxiliary electrode, an organic EL layer formed on the pixel electrode and having a plurality of organic layers including a light emitting layer, and the organic EL layer And at least one organic layer constituting the organic EL layer has a striped opening on the auxiliary electrode, and the transparent electrode layer includes the auxiliary electrode and the transparent electrode layer. Provided is a top emission organic EL display device which is electrically connected through an opening of an organic layer, and the interval between the openings of the organic layer is in a range of 1 mm to 100 mm.

  According to the present invention, the auxiliary electrode is formed, and the interval between the openings of the organic layer is within a predetermined range, thereby suppressing the occurrence of luminance unevenness due to voltage drop and disconnection due to current concentration, Further, when the opening is formed by removing the organic layer by laser ablation, it is possible to reduce scattering of the material of the organic layer to the pixel region and suppress deterioration of display characteristics.

  In the present invention, there is an effect that there is little luminance unevenness, display characteristics are good, and a highly reliable organic EL display device can be obtained.

It is the schematic plan view and sectional drawing which show an example of the top emission type organic electroluminescent display apparatus of this invention. It is a schematic sectional drawing which shows the other example of the top emission type organic electroluminescent display apparatus of this invention. It is process drawing which shows an example of the manufacturing method of the top emission type organic electroluminescence display of this invention. 4 is a graph showing a relationship between an opening of an organic layer and a voltage drop in Example 1. 6 is a schematic plan view illustrating an example of a top emission type organic EL display device according to Example 2. FIG.

  Hereinafter, the top emission type organic EL display device of the present invention will be described in detail. The top emission type organic EL display device may be abbreviated as an organic EL display device.

  The organic EL display device of the present invention is formed on a substrate, a pixel electrode formed on the substrate, an auxiliary electrode formed on the substrate and disposed between the adjacent pixel electrodes, and the substrate. An insulating layer disposed between the adjacent pixel electrodes and between the pixel electrode and the auxiliary electrode, an organic EL layer formed on the pixel electrode and having a plurality of organic layers including a light emitting layer, and the organic A transparent electrode layer formed on the EL layer, at least one of the organic layers constituting the organic EL layer has a stripe-shaped opening on the auxiliary electrode, and the transparent electrode layer is the auxiliary electrode The electrode and the organic layer are electrically connected to each other through an opening, and the distance between the openings of the organic layer is in a range of 1 mm to 100 mm.

First, the organic EL display device of the present invention will be described with reference to the drawings.
FIG. 1A is a schematic plan view showing an example of the organic EL display device of the present invention, and FIG. 1B is a cross-sectional view taken along line AA of FIG. In FIG. 1A, the pixel electrode is indicated by a broken line, the auxiliary electrode is indicated by a one-dot chain line, and an active layer such as an insulating layer and a transparent electrode layer, a wiring such as a TFT, a scanning line or a signal line, and a planarization layer The matrix driving circuit is omitted.
As illustrated in FIGS. 1A and 1B, the organic EL display device 1 includes a substrate 2, a TFT 11 formed on the substrate 2, a planarization layer 17 formed so as to cover the TFT 11, A pixel electrode 3 formed in a pattern on the planarizing layer 17; an auxiliary electrode 4 formed in a pattern on the substrate 2 and disposed between adjacent pixel electrodes 3; and formed on the substrate 2. An insulating layer 5 disposed between adjacent pixel electrodes 3 and between the pixel electrode 3 and the auxiliary electrode 4, and formed on the entire surface of the substrate 2 on which the pixel electrode 3, the auxiliary electrode 4 and the insulating layer 5 are formed. An organic EL layer 6 having a stripe-shaped opening 10 on the electrode 4 and a transparent layer formed on the entire surface of the organic EL layer 6 and electrically connected to the auxiliary electrode 4 through the opening 10 of the organic EL layer 6 And an electrode layer 7. The TFT 11 includes a gate electrode 12, a gate insulating layer 13 formed on the gate electrode 12, a semiconductor layer 14 formed on the gate insulating layer 13, and a source electrode 15 and a drain electrode formed on the semiconductor layer 14. 16, and the TFT 11 and the pixel electrode 3 are connected to each other through a contact hole that penetrates the planarization layer 17. Further, the stripe-shaped openings 10 of the organic EL layer 6 are arranged at a predetermined interval d1.

  Here, the “transparent electrode layer formed on the organic EL layer” means that the transparent electrode layer is formed on the organic EL layer. Usually, as illustrated in FIG. The transparent electrode layer 7 is continuously formed on the entire surface of the substrate 2 on which the pixel electrode 3, the auxiliary electrode 4, the insulating layer 5, and the organic EL layer 6 are formed.

  “The organic EL layer formed on the pixel electrode” means that the organic EL layer is formed on the pixel electrode. Usually, as illustrated in FIG. At least one organic layer to be formed is continuously formed on the substrate 2 on which the pixel electrode 3, the auxiliary electrode 4, and the insulating layer 5 are formed.

  According to the present invention, since the auxiliary electrode is formed and the interval between the openings of the organic layer is within a predetermined range, luminance unevenness due to voltage drop can be prevented, and disconnection due to current concentration can be prevented. In addition, when the organic layer is removed by laser ablation to form the opening, scattering of the organic layer material to the pixel region can be reduced and deterioration of display characteristics can be suppressed.

  Hereinafter, each configuration in the organic EL display device of the present invention will be described.

1. In the present invention, at least one organic layer constituting the organic EL layer is formed on the pixel electrode, the auxiliary electrode, and the insulating layer, and has a stripe-shaped opening on the auxiliary electrode. The transparent electrode layer and the auxiliary electrode are electrically connected through the opening of the organic layer.

  The interval between the openings of the organic layer is in the range of 1 mm to 100 mm, preferably in the range of 5 mm to 50 mm, and more preferably in the range of 10 mm to 50 mm. If the spacing between the openings in the organic layer is too wide, the effect of suppressing the voltage drop will not be sufficiently obtained, resulting in high power consumption, and the current density at the openings in the organic layer will increase, resulting in disconnection and reliability. It may decrease. On the other hand, when the interval between the openings of the organic layer is narrower than the above range, the effect of suppressing the voltage drop is hardly changed, whereas when the openings are formed by removing the organic layer by laser ablation, There is a possibility that the scattering of the material increases and the display characteristics are deteriorated, and the removal of the organic layer is complicated and requires a long time.

  Here, the interval between the openings of the organic layer refers to the distance from the center to the center of the adjacent openings, and is indicated by d1 in FIG.

The arrangement of the openings is not particularly limited as long as the openings are arranged on the auxiliary electrode and the distance between the openings is within a predetermined range, and various arrangements are possible. is there.
Especially, it is preferable that the opening is not arranged for each pixel, that is, for each pixel electrode. This is because if the opening is arranged for each pixel, it takes time to form the opening, and the productivity is lowered and the manufacturing cost is increased.
The openings may be arranged regularly or irregularly, but are usually arranged regularly.

  The shape of the opening of the organic layer in plan view is not particularly limited as long as the transparent electrode layer and the auxiliary electrode can be electrically connected, and examples thereof include a rectangle and an ellipse.

  Here, for example, as shown in FIG. 1A, the stripe-shaped opening 10 on the auxiliary electrode 4 is formed continuously, but the organic layer is removed by laser ablation to form the opening. In this case, since the laser beam is usually intermittently irradiated, there may be a discontinuous portion in a part of the stripe-shaped opening.

The method for forming the opening of the organic layer is not particularly limited as long as it can form a stripe-shaped opening in the organic layer so that a part of the auxiliary electrode is exposed. It is preferable to use a laser ablation method in which the organic layer is removed by irradiating.
The laser light is not particularly limited as long as it can remove the organic layer covering the auxiliary electrode, and the laser light generally used in the method of removing the organic layer by laser ablation should be adopted. Can do. Examples thereof include lasers such as YAG, Ar ions, He—Ne, KrF, and a carbon laser (CO ₂ laser).

2. Auxiliary Electrode The auxiliary electrode in the present invention is formed on the substrate and disposed between adjacent pixel electrodes.

The auxiliary electrode may or may not have optical transparency.
A metal material is used for the auxiliary electrode. Note that the metal material used for the auxiliary electrode can be the same as the metal material used for the pixel electrode, which will be described later, and thus the description thereof is omitted here.
Further, when an auxiliary electrode is formed on the same plane as the pixel electrode as described later, the material used for the auxiliary electrode may be the same as or different from the material used for the pixel electrode. Especially, it is preferable that a pixel electrode and an auxiliary electrode consist of the same material. This is because the pixel electrode and the auxiliary electrode can be formed collectively, and the manufacturing process can be simplified.
Further, as described later, when an auxiliary electrode is formed on the same plane as a wiring such as a scanning line or a signal line of the active matrix driving circuit, the material used for the auxiliary electrode is the same as the material used for the wiring. It may or may not be. Especially, it is preferable that a wiring and an auxiliary electrode consist of the same material. This is because the wiring and the auxiliary electrode can be collectively formed, and the manufacturing process can be simplified.

  As an auxiliary electrode formation position, the auxiliary electrode is disposed between adjacent pixel electrodes, and any auxiliary electrode can be used as long as the auxiliary electrode can exhibit its function of suppressing a voltage drop due to the resistance of the transparent electrode layer. It is not limited. For example, the auxiliary electrode 4 may be formed only on the same plane as the pixel electrode 3 as shown in FIG. 1B, and scanning of the active matrix driving circuit is performed on the same plane as the pixel electrode 3 as shown in FIG. A first auxiliary electrode 4a and a second auxiliary electrode 4b may be formed on the same plane as a line or a signal line (not shown), and the first auxiliary electrode 4a and the second auxiliary electrode 4b may be connected. In the latter case, since the second auxiliary electrode is formed closer to the substrate than the pixel electrode, there is no need to consider light extraction, and the area of the second auxiliary electrode can be increased. The voltage drop can be further suppressed.

  The arrangement of the auxiliary electrode is not particularly limited as long as the auxiliary electrode is arranged between adjacent pixel electrodes and can exhibit the function of the auxiliary electrode to suppress the voltage drop due to the resistance of the transparent electrode layer. It is not a thing and it selects suitably according to the structure of an auxiliary electrode, etc. For example, as shown in FIG. 1B, when the auxiliary electrode 4 is formed only on the same plane as the pixel electrode 3, the auxiliary electrode 4 is disposed between the adjacent pixel electrodes 3. On the other hand, for example, as shown in FIG. 2, the first auxiliary electrode 4a is formed on the same plane as the pixel electrode 3, and the second auxiliary electrode 4b is formed on the same plane as the scanning lines or signal lines (not shown) of the active matrix driving circuit. In the case of being formed above, it is sufficient that the first auxiliary electrode 4a formed on the same plane as the pixel electrode 3 is disposed between the adjacent pixel electrodes 3, and the scanning line of the active matrix drive circuit or The second auxiliary electrode 4b formed on the same plane as the signal line (not shown) does not have to be disposed between the adjacent pixel electrodes 3. In the latter case, the arrangement of the second auxiliary electrode is not dependent on the pixel electrode, but the area of the second auxiliary electrode can be increased as described above, so that the voltage drop due to the resistance of the transparent electrode layer can be further suppressed. it can.

  The shape of the auxiliary electrode in plan view is not particularly limited as long as it can exhibit the function of the auxiliary electrode to suppress the voltage drop due to the resistance of the transparent electrode layer, and depending on the configuration of the auxiliary electrode, etc. Are appropriately selected. For example, as shown in FIGS. 1B and 2, the auxiliary electrode 4 or the first auxiliary electrode 4 a formed on the same plane as the pixel electrode 3 is disposed between the adjacent pixel electrodes 3. The shape of the auxiliary electrode 4 and the first auxiliary electrode 4a in plan view is preferably a shape that does not reduce the light extraction efficiency of the organic EL display device. For example, a lattice shape as shown in FIG. On the other hand, for example, as shown in FIG. 2, the second auxiliary electrode 4 b formed on the same plane as the scanning line or signal line (not shown) of the active matrix driving circuit is formed on the substrate 2 side with respect to the pixel electrode 3. Therefore, there is no need to consider light extraction, and the shape of the second auxiliary electrode 4b in plan view can be an arbitrary shape.

  The thickness of the auxiliary electrode is appropriately adjusted according to the presence or absence of leakage current from the end of the auxiliary electrode, and is preferably in the range of, for example, 10 nm to 1000 nm, and more preferably in the range of 20 nm to 500 nm. preferable. Note that when the auxiliary electrode is formed together with the pixel electrode, the pixel electrode and the auxiliary electrode have the same thickness.

  The method for forming the auxiliary electrode is not particularly limited as long as the auxiliary electrode can be formed in a pattern on the substrate, and a general electrode forming method can be employed. For example, the vapor deposition method using a mask, the photolithographic method, etc. are mentioned. Examples of the vapor deposition method include a sputtering method and a vacuum vapor deposition method. In particular, it is preferable to form the auxiliary electrode together with the pixel electrode and the wiring of the active matrix driving circuit. This is because the manufacturing process can be simplified.

3. Organic EL Layer The organic EL layer in the present invention is formed on the pixel electrode and has a plurality of organic layers including a light emitting layer. Further, as described above, at least one organic layer constituting the organic EL layer has a stripe-shaped opening on the auxiliary electrode.

  The organic layer having a stripe-shaped opening on the auxiliary electrode may be at least one layer, and all organic layers constituting the organic EL layer may have a stripe-shaped opening. A part of the organic layer that constitutes may have a stripe-shaped opening. For example, when the light emitting layer is formed only on the pixel electrode, the light emitting layer does not have a stripe-shaped opening on the auxiliary electrode.

  Examples of the organic layer constituting the organic EL layer include a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer in addition to the light emitting layer. Hereinafter, the organic layer which comprises an organic EL layer is demonstrated.

(1) Light-Emitting Layer The light-emitting layer in the present invention may be a single-color light-emitting layer or a multi-color light-emitting layer, and is appropriately selected according to the colorization method of the organic EL display device.

  The light emitting material used for the light emitting layer may be any material that emits fluorescence or phosphorescence, and examples thereof include dye materials, metal complex materials, and polymer materials. Note that specific pigment materials, metal complex materials, and polymer materials can be the same as those generally used, and thus description thereof is omitted here.

  The thickness of the light-emitting layer is not particularly limited as long as it can provide a function of emitting light by providing a recombination field of electrons and holes, and may be, for example, about 10 nm to 500 nm. it can.

  The method for forming the light emitting layer may be a wet process in which a light emitting layer forming coating solution in which the above light emitting material or the like is dissolved or dispersed in a solvent may be applied, or may be a dry process such as a vacuum deposition method. Good. Among these, a dry process is preferable in terms of luminous efficiency and life.

(2) Hole Injecting and Transporting Layer In the present invention, a hole injecting and transporting layer may be formed between the light emitting layer and the anode.
The hole injection transport layer may be a hole injection layer having a hole injection function, or a hole transport layer having a hole transport function, and the hole injection layer and the hole transport layer are laminated. And may have both a hole injection function and a hole transport function.

  The material used for the hole injecting and transporting layer is not particularly limited as long as it can stabilize the injection and transportation of holes to the light emitting layer, and a general material can be used. .

  The thickness of the hole injecting and transporting layer is not particularly limited as long as the hole injecting function and the hole transporting function are sufficiently exhibited. Specifically, the thickness is in the range of 0.5 nm to 1000 nm, particularly 10 nm to It is preferable to be in the range of 500 nm.

  The formation method of the hole injection transport layer may be a wet process in which a coating liquid for forming a hole injection transport layer in which the above-described materials or the like are dissolved or dispersed in a solvent may be applied. It may be a process and is appropriately selected according to the type of material.

(3) Electron Injecting and Transporting Layer In the present invention, an electron injecting and transporting layer may be formed between the light emitting layer and the cathode.
The electron injection / transport layer may be an electron injection layer having an electron injection function, may be an electron transport layer having an electron transport function, or may be a laminate of an electron injection layer and an electron transport layer. It may have both an electron injection function and an electron transport function.

  The material used for the electron injection layer is not particularly limited as long as it can stabilize the injection of electrons into the light emitting layer, and the material used for the electron transport layer is from the cathode. The material is not particularly limited as long as the injected electrons can be transported to the light emitting layer. A general material can be used as a specific material used for the electron injection layer and the electron transport layer.

  In addition, when an electron injection layer is formed between the light emitting layer and the transparent electrode layer, the electron injection layer is formed on the entire surface of the substrate on which the organic layer having the opening is formed, and the electron injection layer is transparent on the electron injection layer. By forming the electrode layer, the auxiliary electrode, the electron injection layer, and the transparent electrode layer can be electrically connected through the opening of the organic layer. When the electron injection layer is extremely thin, the auxiliary electrode and the transparent electrode layer can be electrically connected even when the electron injection layer is formed in the opening of the organic layer. In this case, since the deterioration of the electron injection layer when forming the opening of the organic layer can be prevented, a material containing an alkali metal such as lithium fluoride, which is relatively unstable, is used for the electron injection layer. It becomes possible.

  The thickness of the electron injection / transport layer is not particularly limited as long as the electron injection function and the electron transport function are sufficiently exhibited.

  The method for forming the electron injecting and transporting layer may be a wet process in which a coating liquid for forming an electron injecting and transporting layer in which the above-described materials or the like are dissolved or dispersed in a solvent may be applied, or by a dry process such as a vacuum evaporation method. There may be, and it chooses suitably according to the kind etc. of material.

4). Pixel electrode The pixel electrode in the present invention is formed in a pattern on a substrate.
The pixel electrode may or may not have optical transparency, but the organic EL display device of the present invention is a top emission type and usually takes out light from the transparent electrode layer side. It is assumed that it does not have transparency.

The pixel electrode may be either an anode or a cathode.
The pixel electrode preferably has a low resistance, and a metal material that is a conductive material is generally used, but an organic compound or an inorganic compound may be used.
For the anode, a conductive material having a large work function is preferably used so that holes can be easily injected. Examples thereof include metals such as Au, Cr, and Mo; inorganic oxides such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide, and indium oxide; and conductive polymers such as metal-doped polythiophene. It is done. These conductive materials may be used alone or in combination of two or more. When two or more types are used, layers made of each material may be stacked.
For the cathode, it is preferable to use a conductive material having a low work function so that electrons can be easily injected. Examples thereof include magnesium alloys such as MgAg, aluminum alloys such as AlLi, AlCa, and AlMg, and alloys of alkali metals and alkaline earth metals such as Li, Cs, Ba, Sr, and Ca. Further, a laminated film of Mo, Al, Mo, a laminated film of Ti, Al, Ti, or the like can also be used.

  The thickness of the pixel electrode is appropriately adjusted according to the presence or absence of leakage current from the end of the pixel electrode, and can be set to, for example, about 10 nm to 1000 nm, and preferably about 20 nm to 500 nm. The thickness of the pixel electrode may be the same as or different from the thickness of the auxiliary electrode described later. Note that when the pixel electrode and the auxiliary electrode are collectively formed, the pixel electrode and the auxiliary electrode have the same thickness.

  The method for forming the pixel electrode is not particularly limited as long as the pixel electrode can be formed in a pattern on the substrate, and a general electrode forming method can be employed. For example, the vapor deposition method using a mask, the photolithographic method, etc. are mentioned. Examples of the vapor deposition method include a sputtering method and a vacuum vapor deposition method.

5. Transparent electrode layer The transparent electrode layer in this invention is formed on the said organic EL layer, and is electrically connected with an auxiliary electrode through the opening part of the organic layer which comprises an organic EL layer.

The transparent electrode layer may be either an anode or a cathode.
The material of the transparent electrode layer is not particularly limited as long as it is a transparent conductive material. For example, an inorganic oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide, indium oxide, And conductive polymers such as metal-doped polythiophene. These transparent conductive materials may be used alone or in combination of two or more. When two or more types are used, layers made of each material may be stacked. Further, a magnesium alloy such as MgAg, or a metal material such as aluminum or calcium can also be used. In this case, a thin film having a light-transmitting property can be used as the transparent electrode layer.

The sheet resistance of the transparent electrode layer is preferably small, specifically 200Ω / □ or less, more preferably 100Ω / □ or less, and particularly preferably 40Ω / □ or less. This is because the voltage drop due to the resistance of the transparent electrode layer can be suppressed.
The sheet resistance can be measured using, for example, a resistivity meter Loresta manufactured by Mitsubishi Chemical Corporation.

  As a method for forming the transparent electrode layer, any method can be used as long as it can be formed on the organic EL layer, and a general electrode forming method can be used. For example, a vacuum deposition method, a sputtering method, an EB deposition method, an ion Examples thereof include a PVD method such as a plating method, a CVD method, and the like.

6). Insulating layer The insulating layer in the present invention is formed in a pattern on the substrate, and is disposed between the adjacent pixel electrodes and between the pixel electrode and the auxiliary electrode. The insulating layer can prevent a short circuit due to a leak current that may occur between adjacent pixel electrodes and between the pixel electrode and the auxiliary electrode.

  As a material of the insulating layer, a material of a general insulating layer in an organic EL display device can be used. For example, a photo-curable resin such as a photosensitive polyimide resin or an acrylic resin, a thermosetting resin, an inorganic material, or the like. Can be mentioned.

The insulating layer may be disposed between adjacent pixel electrodes and between the pixel electrode and the auxiliary electrode, but is preferably formed so as to cover at least an end portion of the pixel electrode. Generation of leakage current from the end portion of the pixel electrode can be suppressed. Usually, as illustrated in FIG. 1B, the insulating layer 5 is formed between the adjacent pixel electrodes 3 and the entire region between the pixel electrode 3 and the auxiliary electrode 4.
As described above, since the insulating layer is formed between adjacent pixel electrodes and between the pixel electrode and the auxiliary electrode, the arrangement of the insulating layer is appropriately selected according to the arrangement of the pixel electrodes. For example, a lattice shape can be mentioned. In addition, a pixel is defined by the insulating layer.

  The thickness of the insulating layer is not particularly limited as long as it defines a pixel and can insulate between adjacent pixel electrodes and between a pixel electrode and an auxiliary electrode. It is preferably within the range of 3 μm to 100 μm, more preferably within the range of 0.5 μm to 50 μm, and particularly preferably within the range of 1 μm to 20 μm.

  The method for forming the insulating layer is not particularly limited as long as the insulating layer can be formed in a pattern on the substrate, and examples thereof include a printing method and a photolithography method.

7). Substrate The substrate in the present invention supports the above-described members.
Since the organic EL display device of the present invention is a top emission type, the substrate may or may not have optical transparency.
The substrate may or may not have flexibility, and is appropriately selected depending on the use of the organic EL display device.
Examples of such a substrate material include glass and resin. A gas barrier layer may be formed on the surface of the substrate.
The thickness of the substrate is appropriately selected depending on the material of the substrate and the use of the organic EL display device, and is specifically about 0.005 mm to 5 mm.

8). Active Matrix Drive Circuit In the present invention, an active matrix drive circuit may be formed on the substrate.
Since an active matrix drive circuit can be used, a description thereof is omitted here.

9. Sealing substrate In the present invention, a sealing substrate may be disposed and sealed on the transparent electrode layer.
Since the organic EL display device of the present invention is a top emission type, the sealing substrate has light transmittance. The light transmittance of the sealing substrate only needs to be transparent to the wavelength in the visible light region. Specifically, the light transmittance for the entire wavelength range in the visible light region is 80% or more. Of these, 85% or more, particularly 90% or more is preferable.
Here, the light transmittance can be measured by, for example, an ultraviolet-visible light spectrophotometer UV-3600 manufactured by Shimadzu Corporation.

  Further, the sealing substrate may or may not have flexibility, and is appropriately selected depending on the use of the organic EL display device.

  The material of the sealing substrate is not particularly limited as long as a light-transmitting sealing substrate can be obtained. For example, inorganic materials such as quartz and glass, acrylic resin, and COP are used. Examples thereof include resins such as cycloolefin polymer, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyimide, polyamideimide, polyethersulfone, polyetherimide, and polyetheretherketone. A gas barrier layer may be formed on the surface of the resin sealing substrate.

  The thickness of the sealing substrate is appropriately selected depending on the material of the sealing substrate and the use of the organic EL display device. Specifically, the thickness of the sealing substrate is about 0.001 mm to 5 mm.

10. Manufacturing Method of Organic EL Display Device The manufacturing method of the organic EL display device of the present invention is not particularly limited as long as it is a method capable of manufacturing the organic EL display device having the above configuration, but it is preferable to remove the organic layer by laser ablation. Hereinafter, an example of the manufacturing method of the organic EL display device of the present invention will be given.

  3A to 3E are process diagrams showing an example of a method for manufacturing an organic EL display device of the present invention. First, as illustrated in FIG. 3A, the pixel electrode 3 and the auxiliary electrode 4 are formed in a pattern on the substrate 2. Next, as illustrated in FIG. 3B, the insulating layer 5 is formed in a pattern between the adjacent pixel electrodes 3 on the substrate 2 and between the pixel electrode 3 and the auxiliary electrode 4. Next, as illustrated in FIG. 3C, the organic EL layer 6 is formed on the entire surface of the substrate 2 on which the pixel electrode 3, the auxiliary electrode 4, and the insulating layer 5 are formed. Next, as illustrated in FIG. 3D, the organic EL layer 6 formed on the auxiliary electrode 4 is irradiated with laser light L to remove the organic EL layer 6 on the auxiliary electrode 4, and the auxiliary electrode 4. Is exposed to form the opening 10. At this time, the openings 10 are formed at a predetermined interval. Thereafter, as illustrated in FIG. 3E, the transparent electrode layer 7 is formed on the organic EL layer 6 so as to be electrically connected to the auxiliary electrode 4 through the opening 10. In this way, the organic EL display device 1 is obtained.

  In the present invention, the openings are formed in the organic layer at predetermined intervals, so that the time for forming the openings can be shortened, the productivity can be improved, and the manufacturing cost can be reduced.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

[Example 1]
A simulation was performed on the relationship between the gap between the openings of the organic layer and the voltage drop when the surface resistance of the transparent electrode layer and the auxiliary electrode was changed.
The voltage drop was calculated by the following formula (1).
ΔV = Σ (n) ir = 1 / 2n (n + 1) ir (1)
(In the above formula (1), ΔV is the voltage drop (V), i is the current (A), r is the sheet resistance (Ω / □), and n is the number of light-emitting pixels existing between the openings of the organic layer. )
The calculation conditions are as shown below.
• The current flowing through each pixel was set to a constant value.
-The area of one pixel was 300 μm × 300 μm.
The transparent electrode layer was a laminated film of Ca and Al, the auxiliary electrode was a laminated film of Ti and Al, the surface resistance of the transparent electrode layer was 40Ω / □, and the surface resistance of the auxiliary electrode was 0.1Ω / □.
The luminance was 3000 cd / m ² and the luminous efficiency was 60 cd / A.
-The space | interval of the opening part of an organic layer was changed within the range of 0.45 mm-300 mm.
The evaluation results are shown in Table 1 and FIG.

  In consideration of power consumption, it was confirmed that ΔV <1.5V can be set within the allowable range, and the interval between the openings is desirably 100 mm or less. Further, it was found that when the gap between the openings was 10 mm or less, the voltage drop hardly changed and the performance was almost equivalent.

[Example 2]
(Production of organic EL display device)
On the substrate made of alkali-free glass with a thickness of 0.7 mm, a Mo—Al—Mo laminated film with a thickness of 500 nm was formed by sputtering to form a second auxiliary electrode. The thickness of the Mo film was 50 nm, and the thickness of the Al film was 400 nm. Next, a first insulating layer having striped openings with a pitch of 100 μm was formed on the substrate by photolithography. Next, a Ti—Al—Ti laminated film having a thickness of 500 nm was formed on the first insulating layer by a sputtering method, and was patterned by a photolithography method to form a pixel electrode and a first auxiliary electrode. The pixel electrodes were formed in a stripe shape having a width of 70 μm and a pitch of 100 μm, and the stripe-shaped openings of the first insulating layer were positioned between adjacent pixel electrodes. The second auxiliary electrode was formed in the stripe-shaped opening of the first insulating layer. Next, a second insulating layer having a width of 7 μm and a thickness of 1.5 μm was formed between the pixel electrode and the auxiliary electrode.
Next, a hole injection layer having a thickness of 100 nm and a light emitting layer having a thickness of 300 nm are formed on the entire surface of the substrate on which the pixel electrode, the first auxiliary electrode, the second auxiliary electrode, the first insulating layer, and the second insulating layer are formed. And an electron transport layer having a thickness of 300 nm were sequentially formed.

After the formation of the electron transport layer, irradiation with YAG laser light having an energy of 500 mJ / cm ² , a spot diameter of 15 μmφ, a wavelength of 355 nm, and a pulse width of 5 nsec is performed by shifting one shot at a time to cover the auxiliary electrode, a hole injection layer, a light emitting layer, The layer was removed in a stripe shape, and the auxiliary electrode was exposed to form an opening. At this time, as illustrated in FIG. 5, the distance d1 between the openings 10 of the hole injection layer, the light emitting layer, and the electron injection layer was changed as shown in Table 2 below.

Next, lithium fluoride is vacuum-deposited to a thickness of 0.5 nm so as to be electrically connected to the first auxiliary electrode exposed at the openings of the hole injection layer, the light emitting layer, and the electron injection layer. A film was formed to form an electron injection layer. Next, the film was formed by vacuum deposition so that the calcium film thickness was 10 nm and the aluminum film thickness was 5 nm to form a transparent electrode layer.
Then, the sealing substrate which apply | coated the adhesive material was bonded and sealed.

[Comparative Example 1]
An organic EL display device was produced in the same manner as in Example 2 except that no opening was formed in the hole injection layer, the light emitting layer, and the electron injection layer.

[Evaluation]
Regarding the organic EL display device obtained in Example 2, scattering of the material of the organic layer into the pixel region and disconnection were evaluated.

The scattering of the organic layer material into the pixel region was evaluated by measuring the luminance using a luminance meter BM-8 manufactured by Topcon Corporation. Specifically, when the luminance of the organic EL display device of Comparative Example 1 was Xcd / m ² and the luminance of the organic EL display device of Example 2 was Ycd / m ² , the evaluation was performed by the following formula (2).
Luminance ratio (%) = Y / X × 100 (2)
The luminance ratio was 100% for “A”, less than 100% for 95% or more as “B”, less than 95% for 85% or more for “C”, and less than 85% for “D”.

About disconnection, the terminal was connected to the auxiliary electrode, and the current density that flowed when the current was injected was evaluated. 0.15 mA / mm ² or more which do not break even by applying a current so that the current density "A", one that does not break if a current density of 0.1 mA / mm ² or less "B", 0. If the current density was 05 mA / mm ² or less, the one that was not disconnected was designated as “C”.
The evaluation results are shown in Table 2.

  It was confirmed that when the distance between the openings is 1 mm or more, the scattering of the organic layer material to the pixel region can be sufficiently reduced, and the occurrence of disconnection due to current concentration can be suppressed.

DESCRIPTION OF SYMBOLS 1 ... Organic EL display device 2 ... Substrate 3 ... Pixel electrode 4 ... Auxiliary electrode 5 ... Insulating layer 6 ... Organic EL layer 7 ... Transparent electrode layer 10 ... Opening d1 ... Space | interval of opening

Claims (1)

A substrate,
A pixel electrode formed on the substrate;
An auxiliary electrode formed on the substrate and disposed between the adjacent pixel electrodes;
An insulating layer formed on the substrate and disposed between the adjacent pixel electrodes and between the pixel electrode and the auxiliary electrode;
An organic electroluminescent layer formed on the pixel electrode and having a plurality of organic layers including a light emitting layer;
A top emission type organic electroluminescence display device comprising: a transparent electrode layer formed on the organic electroluminescence layer;
At least one of the organic layers constituting the organic electroluminescence layer has a stripe-shaped opening on the auxiliary electrode,
The transparent electrode layer is electrically connected to the auxiliary electrode through the opening of the organic layer;
A top emission type organic electroluminescence display device characterized in that an interval between openings of the organic layer is in a range of 1 mm or more and 100 mm or less.

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