JP4165145B2 - Organic light emitting display - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an organic light emitting display device.
[0002]
[Prior art]
With the advent of the full-fledged multimedia era, flat display devices used as man-machine interfaces have been highlighted. Conventionally, a liquid crystal display is used as the flat display device. However, the liquid crystal display device has problems such as a narrow viewing angle and low-speed response.
[0003]
In recent years, organic light emitting display devices have attracted attention as next-generation flat display devices. This organic light emitting display device has excellent characteristics such as self light emission, wide viewing angle, and high speed response characteristics.
[0004]
The structure of a conventional organic light emitting device is configured by forming a first electrode such as ITO, an organic layer composed of a hole transport layer, a light emitting layer, an electron transport layer, and the like, and a low work function upper electrode on a glass substrate. ing. When a voltage of about several volts is applied between the two electrodes, holes and electrons are injected into the electrodes, coupled with each other in the light emitting layer via the transport layer, and excitons are generated. When the excitons return to the ground state. It emits light. And this emitted light permeate | transmits the 1st electrode which has transparency, and is taken out from the substrate side back surface.
[0005]
Display devices using organic light emitting elements for pixels include a simple matrix organic light emitting display device and an active matrix organic light emitting display device. In the simple matrix organic light emitting display device, organic layers such as a hole transport layer, a light emitting layer, and an electron transport layer are formed at positions where a plurality of anode lines and cathode lines intersect, and each pixel is selected during one frame period. Lights only for hours. The selection time is a time width obtained by dividing one frame period by the number of anode lines. Simple matrix organic light emitting display devices have the advantage of simple structure.
[0006]
However, since the selection time is shortened as the number of pixels increases, it is necessary to increase the driving voltage, increase the instantaneous luminance during the selection time, and set the average luminance during one frame period to a predetermined value. Therefore, there is a problem that the lifetime of the organic light emitting element is shortened. In addition, since the organic light-emitting element is current-driven, a voltage drop due to wiring resistance occurs particularly on a large screen, and a voltage cannot be applied uniformly to each pixel, resulting in luminance variations in the display device. In view of the above, the simple matrix organic light-emitting display device has limitations in high definition and large screen.
[0007]
On the other hand, in the active matrix organic light emitting display device, a driving element composed of switching elements and capacitors of 2 to 4 thin film transistors is connected to an organic light emitting element that constitutes each pixel, so that all lighting during one frame period is possible. It becomes possible. Therefore, it is not necessary to increase the luminance, and the lifetime of the organic light emitting element can be extended. Therefore, it is considered that an active matrix organic light emitting display device is advantageous in high definition and large screen.
[0008]
In the conventional organic light emitting display device, since the emitted light is taken out from the back side of the substrate, the aperture ratio is limited in the active matrix organic light emitting display device in which the driving unit is provided between the substrate and the organic light emitting element.
[0009]
In order to solve the above problems, there is an attempt to make the upper electrode transparent and to extract emitted light from the upper electrode side.
[0010]
In the upper light extraction structure, a transparent conductive film is used for the upper electrode. In this case, low temperature film formation is indispensable in order not to damage the organic layer serving as the base layer. As a result, the resistivity is as high as 300 times or more compared to a metal film such as Al. Even when the upper electrode is made of a normal metal film, the metal film thickness cannot be increased in order to reduce the damage of the underlying organic layer, and the high resistance of the upper electrode becomes a problem as the panel size increases.
[0011]
Japanese Patent Application Laid-Open No. 2001-230086 discloses an organic light emitting device that realizes a lower resistance of the upper electrode by arranging an auxiliary electrode made of a low resistance material connected to the upper electrode.
[0012]
[Problems to be solved by the invention]
In the prior art, the resistance of the upper electrode is reduced by forming an auxiliary electrode between the adjacent organic light emitting media and the organic light emitting medium or on an insulating film that is in question with the organic light emitting medium. However, when an auxiliary electrode is disposed between the light emitting medium and the light emitting medium, the emitted light from the light emitting element propagates to the side, and it is possible to prevent crosstalk that affects adjacent elements. Since the organic light emitting medium formed on the end of the electrode cannot cover the end of the lower electrode and is short-circuited with the upper electrode, it is likely to cause a leak current and it is difficult to form a stable element. On the other hand, when the auxiliary electrode is formed on the insulating film, it is difficult to completely prevent the crosstalk because the adjacent light emitting layer is usually composed of a transparent or translucent insulating film. Met.
[0013]
An object of the present invention is to provide an organic light-emitting display device that is uniform and easy to see by reducing the variation in luminance due to wiring resistance by reducing the surface resistance of the upper electrode and preventing crosstalk between elements. .
[0014]
Another object of the present invention is to provide an organic light emitting display device that is uniform and easy to see by preventing crosstalk between elements.
[0015]
[Means for Solving the Problems]
According to an embodiment of the present application, an organic light emitting display device having a plurality of pixels, each of the plurality of pixels having an organic light emitting element, the organic light emitting element includes an organic light emitting layer and the organic light emitting layer. Is configured to take out light emitted from the organic light emitting layer from the upper electrode side, the end of the lower electrode of the organic light emitting element is covered with an insulating film, The insulating film is a contact hole formed in a stripe shape between adjacent pixels of a plurality of pixels. Formed A light reflecting layer made of a conductive material is disposed in a contact hole formed in a stripe shape, and the light reflecting layer is electrically connected to the upper electrode of each pixel.
[0016]
In configuring the organic light emitting display device of the present invention, the upper electrode preferably includes at least one of a transparent conductive oxide, a light-transmissive metal thin film, and an organic conductive film.
[0017]
In configuring the organic light emitting display device of the present invention, it is desirable that the reflective layer has at least one film of a low resistance material than the upper electrode. That is, in order to extract light from the upper electrode side, it is desirable that the material is not only conductive but also highly transparent. The resistance value of the upper electrode is preferably in the range of 10 to 1 MΩ / □, and the transmittance is preferably 30% or more.
[0018]
In constructing the organic light emitting display device of the present invention, it is desirable that the reflective layer has at least one kind of metal or alloy layer. For example, it is desirable to have at least one alloy layer containing one or more of Al, Au, Pt, Cu, Ag, Ni, Mo, W, Cr, and Ta, or one or more. In particular, it is desirable to use a material that does not form a high resistance interface, such as Mo or Mo alloy, for the layer that forms the interface with the upper electrode.
[0019]
In configuring the organic light emitting display device of the present invention, the reflective layer is preferably a film made of a material having an etching rate different from that of the lower electrode. That is, the etching rate of the reflection layer and the etching rate of the lower electrode are different, so that the light reflection layer can be processed by a photolithography process.
[0020]
Further, in constituting the organic light emitting display device of the present invention, it is desirable that the reflective layer is formed and processed before the organic layer is formed. This is because it is difficult to completely protect the organic layer from the etching solution and the etching gas. Therefore, damage to the organic layer can be eliminated by finishing the formation and processing of the conductive reflective layer before forming the organic layer. Note that the reflective layer may be formed by a plating method.
[0021]
In constructing the organic light emitting display device of the present invention, the reflective layer covers the upper portion of the insulating film. By forming the conductive film over the insulating film, the resistance of the upper electrode can be further reduced.
[0022]
Further, in constituting the organic light emitting display device of the present invention, it is preferable that the reflective layer is formed thinner as it goes upward. That is, by applying a forward taper to the reflective layer, it is possible to reflect the light propagated laterally and take it out to the top.
[0023]
In configuring the organic light emitting display device of the present invention, it is desirable that the upper electrode is formed on the reflective layer. By forming the upper electrode so as to cover the reflective layer, the resistance of the upper electrode can be reduced efficiently.
[0024]
In configuring the organic light emitting display device of the present invention, it is desirable to have a light shielding layer on the reflective layer. By arranging the light shielding layer, an organic light emitting display device with better visibility can be provided.
[0025]
Here, a large number of pixels are arranged in the vertical and horizontal directions of the screen of the display device and indicate the smallest unit for displaying characters and graphics.
[0026]
In addition, the sub-pixel refers to a minimum unit that further divides a pixel in a display device that performs color display. A structure in which pixels are composed of sub-pixels of three colors of green, red, and blue is common.
[0027]
The display area refers to an area where an image is displayed on the display device. The organic light emitting device has a structure in which a lower electrode, a first injection layer, a first transport layer, a light emitting layer, a second transport layer, a second injection layer upper electrode, and a protective layer or a counter substrate are formed on a substrate. Take.
[0028]
The organic light emitting device is roughly divided into the following two structures.
[0029]
First, the lower electrode is an anode and the upper electrode is a cathode. In this case, the first injection layer and the first transport layer are a hole injection layer and a hole transport layer, respectively. The second transport layer and the second injection layer become an electron transport layer and an electron injection layer, respectively.
[0030]
Next, the lower electrode is a cathode and the upper electrode is an anode. In this case, the first injection layer and the first transport layer are an electron injection layer and an electron transport layer, respectively. The second transport layer and the second injection layer become a hole transport layer and a hole injection layer, respectively.
[0031]
In the above configuration, a structure without the first injection layer or the second injection layer is also conceivable. In addition, the first transport layer or the second transport layer has a structure that also serves as the light emitting layer. The anode mentioned here is preferably a conductive film having a large work function that increases the efficiency of hole injection. Specific examples include gold and platinum, but are not limited to these materials.
[0032]
As the anode, In ₂ O _Three -SnO ₂ Transparent conductive film, In ₂ O _Three -ZnO type transparent conductive film is mentioned. In particular, In ₂ O _Three -SnO ₂ The system transparent conductive film is used for a pixel electrode of a liquid crystal display device. Examples of the method for producing the transparent electrode material include sputtering, EB vapor deposition, and ion plating.
[0033]
In ₂ O _Three -SnO ₂ Transparent conductive film, In ₂ O _Three The work functions of the —ZnO-based transparent conductive film are 4.6 eV and 4.6 eV, respectively, but can be increased to 5.2 eV by UV irradiation, oxygen plasma treatment, or the like.
[0034]
In ₂ O _Three -SnO ₂ In the case of the system transparent conductive film, a polycrystalline state is obtained when the substrate temperature is increased to about 200 ° C. by sputtering. In the polycrystalline state, since the etching rate is different between the crystal grains and the crystal grain interface, the amorphous state is desirable.
[0035]
In addition, the provision of the hole injection layer for the anode eliminates the need to use a material having a high work function, and an ordinary conductive film is sufficient. Specifically, metals such as aluminum, indium, molybdenum and nickel, alloys using these metals, and inorganic materials such as polysilicon, amorphous silicon, tin oxide, indium oxide, indium tin oxide (ITO) Is desirable.
[0036]
In addition, organic materials such as polyaniline and polythiophene using a coating method with a simple formation process, and conductive ink are desirable. Of course, the material is not limited to these materials, and two or more of these materials may be used in combination.
[0037]
The hole injection layer mentioned here is preferably a material having an appropriate ionization potential in order to lower the injection barrier between the anode and the hole transport layer. It is also desirable to fill the surface irregularities of the underlayer. In the case of a foreign body, steel phthalocyanine, a star-perstamine compound, polyaniline, polythiophene, vanadium oxide, molyptene oxide, ruthenium oxide, aluminum oxide, and the like can be mentioned, but not limited thereto.
[0038]
The hole injection layer here has a role of transporting holes and injecting them into the light emitting layer. Therefore, it is desirable that the hole mobility is high. It is also desirable that it be chemically stable. It is also desirable that the ionization potential is small. Also, it is desirable that the electron affinity is small. Also, it is desirable that the glass transition temperature is high. Specifically, N, N′-bis (3-methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4′diamine (TPD), 4,4′-bis [ N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD), 4,4 ′, 4 ″ -tri (N-carbazolyl) triphenylamine (TCTA), 1,3,5-tris [N -(4-Diphenylaminophenyl) phenylamino] benzene (p-DPA-TDAB) is desirable, and of course not limited to these materials, and two or more of these materials may be used in combination. .
[0039]
The light emitting layer here refers to a layer that emits light at a wavelength specific to the material by recombination of injected holes and electrons. There are a case where the host material itself forming the light emitting layer emits light and a case where a dopant material added to the host in a small amount emits light. Dissimilar host materials include distyrylarylene derivatives (DPVBi), silole derivatives (2PSP) having a benzene ring in the skeleton, oxodiazole derivatives (EM2) having a triphenylamine structure at both ends, and verinones having a phenanthrene group Derivative (P1), oligothiophene derivative having triphenylamine structure at both ends (BMA-3T), berylene derivative (tBu-PTC), tris (8-quinolinol) aluminum, polybaraphenylene vinylene derivative, polythiophene derivative, polyrose Phenylene derivatives, polysilane derivatives, and polyacetylene derivatives are desirable. Of course, the material is not limited to these materials, and two or more of these materials may be used in combination.
[0040]
Next, specific dovant materials include quinacridone, coumarin 6, nile red, luprene, 4- (dicyanomethylene) -2-methyl-6- (para-dimethylaminostyryl) -4H-pyran (DCM), diene. A carbazole derivative is desirable. Of course, the material is not limited to these materials, and two or more of these materials may be used in combination.
[0041]
The electron transport layer here has a role of transporting electrons and injecting them into the light emitting layer. Therefore, it is desirable that the electron mobility is high. Specifically, tris (8-quinolinol) aluminum, oxadiazole derivatives, silole derivatives, and zinc benzothiazole complexes are desirable. Of course, the material is not limited to these materials, and two or more of these materials may be used in combination.
[0042]
The electron injection layer here is used to improve the efficiency of electron injection from the cathode to the electron transport layer. Specifically, lithium fluoride, magnesium fluoride, calcium fluoride, strontium fluoride, barium fluoride, magnesium oxide, and aluminum oxide are desirable. Of course, the material is not limited to these materials, and two or more of these materials may be used in combination.
[0043]
The cathode referred to here is preferably a conductive film having a small work function that increases the efficiency of electron injection.
[0044]
Specific examples include a magnesium / silver alloy, an aluminum / lithium alloy, an aluminum / calcium alloy, an aluminum / magnesium alloy, and metallic calcium, but are not limited to these materials.
[0045]
If the above-described electron transport layer is provided, it is not necessary to use a material having a low work function as a condition for the cathode, and a general metal material can be used. Specifically, metals such as aluminum, indium, molybdenum and nickel, alloys using these metals, polysilicon, and amorphous silicon are desirable.
[0046]
In the present invention, when a cathode is used as the upper electrode, it is desirable to provide an electron injection layer below the cathode. By providing the electron injection layer, a work function transparent conductive film can be used for the cathode. Specifically, In ₂ O _Three -SnO ₂ Transparent conductive film, In ₂ O _Three -ZnO type transparent conductive film is mentioned. In particular, In ₂ O _Three -SnO ₂ The system transparent conductive film is used for a pixel electrode of a liquid crystal display device. Examples of the method for producing the transparent electrode material include sputtering, EB vapor deposition, and ion plating.
[0047]
The protective layer referred to here is formed on the upper electrode and is in the atmosphere H ₂ O, O ₂ It is intended to prevent from entering the upper electrode or the organic layer below it.
[0048]
Specifically, SiO ₂ , SiN _X , Al ₂ O _Three Inorganic materials such as polychloroethylene, polyethylene terephthalate, polyoxymethylene, polyvinyl chloride, polyvinylidene fluoride, cyanoethyl pullulan, polymethyl methacrylate, polysulfone, polycarbonate, polyimide, etc., but are limited to these materials I don't mean.
[0049]
Another embodiment of the present application is an organic light emitting display device having a plurality of pixels, each of the plurality of pixels having an organic light emitting element, and the organic light emitting element sandwiches the organic light emitting layer and the organic light emitting layer. The upper electrode and the lower electrode are configured to extract light emitted from the organic light emitting layer from the upper electrode side, and the end of the lower electrode of the organic light emitting element is covered with an insulating film. Is a contact hole formed in a stripe shape between adjacent pixels of a plurality of pixels. Formed A light shielding layer made of a conductive material is disposed in the contact hole formed in a stripe shape, and the light shielding layer is electrically connected to the upper electrode of each pixel.
[0050]
This is because by arranging the light shielding layer, the light reflection suppressing layer functions as a black matrix and the visibility is improved.
[0051]
According to another embodiment of the present application, in the organic light emitting display device having a plurality of pixels, each of the plurality of pixels has an organic light emitting element, and the organic light emitting element includes the organic light emitting layer and the organic light emitting element. It is configured to have an upper electrode and a lower electrode sandwiching the layers, and takes out the emitted light of the organic light emitting layer from the upper electrode side, the end of the lower electrode of the organic light emitting element is covered with an insulating film, In other words, a light shielding layer is disposed between the insulating films in the adjacent pixels of the plurality of pixels.
[0052]
This light reflection suppression layer functions as a black matrix and improves visibility.
[0053]
DETAILED DESCRIPTION OF THE INVENTION
(Example 1)
Hereinafter, examples of the organic light emitting display device of the present invention will be described. FIG. 1 is a plan view of an organic light emitting display device according to the present embodiment, and FIG. 2 is a cross-sectional view of FIG.
[0054]
The organic light emitting display device according to this embodiment is characterized in that in the organic light emitting display device having a plurality of pixels, each of the plurality of pixels has an organic light emitting element. The organic light emitting element includes the organic light emitting layer 122 and the organic light emitting layer 122. The upper electrode 125 and the lower electrode 115 sandwiching the organic light emitting layer 122 are configured to extract light emitted from the organic light emitting layer 122 from the upper electrode 125 side, and the end of the lower electrode 115 of the organic light emitting element. Is covered with an insulating film (third interlayer insulating film 120), and between the insulating film (third interlayer insulating film 120) and the insulating film (third interlayer insulating film 120) in adjacent pixels of the plurality of pixels. A light reflecting layer 130 of a conductive material layer is disposed, and the light reflecting layer 130 is electrically connected to the upper electrode 125 of each pixel.
[0055]
Hereinafter, a method for manufacturing the organic light emitting display device of this embodiment will be described.
[0056]
An amorphous silicon (a-Si) film having a thickness of 50 nm is formed on the glass substrate 116 by using a low pressure chemical vapor deposition method (LPCVD method). Raw material is Si ₂ H ₆ The substrate temperature was 450 ° C. Next, the entire surface of the film was laser annealed using a XeCl excimer laser. Laser annealing was performed in two stages. The first and second irradiation energy is 188mJ / cm respectively. ² 290mJ / cm ² Met. Thereby, a-Si was crystallized to become polycrystalline silicon (p-Si). Next, the p-Si film is made CF _Four The active layer 103 of the first transistor 101, the active layer 103 ′ of the second transistor 102, and the capacitor lower electrode 105 were formed by patterning using dry etching.
[0057]
Next, a 100 nm-thickness SiO film is formed as the gate insulating film 117. ₂ A film was formed.
SiO ₂ The film was formed by plasma enhanced chemical vapor deposition (PECVD) using tetraethoxysilane (TEOS) as a raw material.
[0058]
Next, a TiW film having a film thickness of 50 nm was produced as the gate electrodes 107 and 107 ′ by sputtering and was subjected to buttering. In addition, the scanning line 106 and the capacitor upper electrode 108 were also buttered.
[0059]
Next, 4 × 10 4 is applied to the patterned p-Si layer from the top of the gate insulating film 117 by ion implantation. ¹⁵ Ion / cm ² , P ions with an energy of 80 keV were implanted. P ions are not implanted into the region having the gate electrode on the upper portion, and become active layers 103 and 103 '.
[0060]
Next, substrate 116 is inert N ₂ In an atmosphere, heating was performed at 300 ° C. for 3 hours to activate the ions so that doping was effectively performed. The p-Si ion-implanted region had a surface resistance value of 2 kΩ / □. Furthermore, silicon nitride (SiN) is used as the first interlayer insulating film 118. _X ) A film was formed. The film thickness is 200 nm.
[0061]
Next, contact holes were formed in the gate insulating film 117 and the first interlayer insulating film 118 above both ends of the active layers 103 and 103 ′. Further, a contact hole was formed in the first interlayer insulating film 118 above the gate electrode 107 ′ of the second transistor.
[0062]
An Al film having a thickness of 500 nm is formed thereon by sputtering. The signal line 109 and the first current supply line 110 are formed by a photolithography process. Further, the source electrode 112 and the drain electrode 113 of the first transistor 101, and the source electrode 112 ′ and the drain electrode 113 ′ of the second transistor 102 are formed.
[0063]
The capacitor lower electrode 105 and the drain electrode 113 of the first transistor 101 are connected. In addition, the source electrode 112 of the first transistor 101 and the signal line 109 are connected.
[0064]
Further, the drain electrode 113 of the first transistor is connected to the gate electrode 107 ′ of the second transistor. Further, the drain electrode 113 ′ of the second transistor is connected to the first current supply line 110. Further, the upper electrode 108 of the capacitor 104 is connected to the first current supply line 110.
[0065]
Next, as the second interlayer insulating film 119, SiN _X A film was formed. The film thickness is 500 nm. A contact hole is provided on the drain electrode 112 'of the second transistor. A 150 nm thick ITO film is formed thereon using a sputtering method, and a lower electrode 115 is formed using a photolithographic method.
[0066]
Next, as the third interlayer insulating film 120, a positive photosensitive protective film (PC452) manufactured by JSR was formed. A film was formed by a spin coating method under a coating condition of 1000 rpm / 30 seconds, a substrate was placed on a hot plate, and prebaked at 90 ° C./2 minutes.
[0067]
The film thickness of the third interlayer insulating film 120 formed of PC452 was 1 μm and covered the edge of the lower electrode 115 by 3 μm.
[0068]
Next, the structure of the organic light-emitting element serving as a pixel will be described with reference to FIG. The glass substrate 116 formed up to the lower electrode 115 was subjected to ultrasonic cleaning for 3 minutes in the order of acetone and pure water. After washing and spin drying, it was dried in an oven at 120 ° C. for 30 minutes.
[0069]
Next, a 500 nm Al film 131 and a 20 nm Mo film 132 were sequentially formed by sputtering. The light reflecting layer 130 is formed by a photolithography process.
[0070]
Next, a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter abbreviated as α-NPD film) having a film thickness of 50 nm is formed on the lower electrode 115 by vacuum deposition. did.
[0071]
About 60 mg of the raw material was put in a Mo sublimation boat, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. A shadow mask was used for pattern formation. The vapor deposition region was 1.2 times each side of the first electrode. This α-NPD film functions as the hole transport layer 121.
[0072]
A co-deposited film of tris (8-quinolinol) aluminum and quinacridone (hereinafter abbreviated as Alq and Qc, respectively) having a film thickness of 20 nm was formed thereon by a binary simultaneous vacuum deposition method.
[0073]
About 40 mg and 10 mg of Alq and Qc raw materials are put in two Mo sublimation boats, respectively, and the deposition rates are controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. And deposited. The Alq + Qc co-evaporated film functions as the light emitting layer 122.
[0074]
An Alq film having a thickness of 20 nm was formed thereon by vacuum deposition.
[0075]
About 40 mg of the raw material was put in a Mo sublimation boat, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. The Alq film functions as the electron transport layer 123.
[0076]
An alloy film of Mg and Ag was formed thereon as the electron injection layer 124. Using the binary simultaneous vacuum deposition method, the deposition rates were set to 0.14 ± 0.05 nm / s and 0.01 ± 0.005 nm / s, respectively, and a film thickness of 10 nm was deposited.
[0077]
Next, an In—Zn—O film (hereinafter abbreviated as IZO film) with a thickness of 50 nm was formed by a sputtering method. This film functions as the upper electrode 125 and is an amorphous oxide film. The target used was In / (In + Zn) = 0.83.
[0078]
The film formation conditions are Ar: O ₂ The atmosphere is mixed gas and the degree of vacuum is 1 Pa. Sputtering output is 0.2 W / cm. ² It was. The upper electrode 125 made of a Mg: Ag / In—ZnO laminated film functioned as a cathode, and the transmittance was 65%.
[0079]
Next, SiN having a film thickness of 50 nm is formed by sputtering. _X A film was formed. The film functions as a protective layer 126.
[0080]
In the organic light emitting display device of this example, an IZO film was used for the upper electrode 125 in order to extract emitted light from the protective layer side. The IZO film has a sheet resistance of 200Ω / □.
[0081]
When an IZO film is used for the upper electrode 125 and the upper electrode 125 and the second current supply line 111 are connected, as shown in FIG. 3A, the feeding point for the upper electrode 125 of each pixel is set to the display amount of the panel. When the feed point and the upper electrode 125 of each pixel are connected via the second current supply line 111, the one disposed at the end of the display area of the panel and the center of the display area of the panel In the pixels arranged in, a difference occurs in the wiring resistance value due to the IZO film, and the voltage applied to the pixels varies, resulting in luminance variations in the panel.
[0082]
On the other hand, in the organic light emitting display device of this embodiment, as shown in FIGS. 2 and 3B, a light reflecting layer formed between each pixel is used as an auxiliary electrode of the upper electrode.
[0083]
The upper electrode 125 and the light reflection layer 130 have a total wiring resistance of about 0.2Ω, and the wiring resistance value in each pixel is so small that it can be ignored.
[0084]
(Example 2)
Next, an organic light emitting display device using the upper electrode as an anode will be described with reference to FIG. FIG. 4 is a cross-sectional view taken along the pixel area AA ′ as in FIG.
[0085]
In the present embodiment, unlike the first embodiment, the upper electrode 125 is configured as an anode and the lower electrode 115 is configured as a cathode.
[0086]
An amorphous silicon (a-Si) film having a thickness of 50 nm is formed on the glass substrate 116 by using a low pressure chemical vapor deposition method (LPCVD method). Raw material is Si ₂ H ₆ The substrate temperature was 450 ° C. Next, the entire surface of the film was laser annealed using a XeCl excimer laser. Laser annealing was performed in two stages. The first and second irradiation energy is 188mJ / cm respectively. ² 290mJ / cm ² Met. Thereby, a-Si was crystallized to become polycrystalline silicon (p-Si).
[0087]
Next, the p-Si film is made CF _Four The active layer 103 of the first transistor 101, the active layer 103 ′ of the second transistor 102, and the capacitor lower electrode 105 were formed by patterning using dry etching.
[0088]
Next, a 100 nm-thickness SiO film is formed as the gate insulating film 117. ₂ A film was formed.
SiO ₂ The film was formed by plasma enhanced chemical vapor deposition (PECVD) using tetraethoxysilane (TEOS) as a raw material.
[0089]
Next, a TiW film having a thickness of 50 nm was formed as the gate electrodes 107 and 107 ′ by sputtering and patterned. In addition, the scanning line 106 and the capacitor upper electrode 108 were also buttered.
[0090]
Next, 4 × 10 4 is applied to the patterned p-Si layer from the top of the gate insulating film 117 by ion implantation. ¹⁵ Ion / cm ² , P ions with an energy of 80 keV were implanted. In the region where the gate electrode is located on the upper side, P ions are not implanted and become the active layers 103 and 103 '. ₂ In an atmosphere, heating was performed at 300 ° C. for 3 hours to activate the ions so that doping was effectively performed. The p-Si ion-implanted region had a surface resistance value of 2 kΩ / □. Furthermore, silicon nitride (SiN) is used as the first interlayer insulating film 118. _X ) A film was formed. The film thickness is 200 nm.
[0091]
Next, contact holes were formed in the gate insulating film 117 and the first interlayer insulating film 118 above both ends of the active layers 103 and 103 ′. Further, a contact hole was formed in the first interlayer insulating film 118 above the gate electrode 107 ′ of the second transistor.
[0092]
An Al film having a thickness of 500 nm is formed thereon by sputtering. The signal line 109 and the first current supply line 110 are formed by a photolithography process. Further, the source electrode 112 and the drain electrode 113 of the first transistor 101, and the source electrode 112 ′ and the drain electrode 113 ′ of the second transistor 102 are formed. The capacitor lower electrode 105 and the drain electrode 113 of the first transistor 101 are connected. In addition, the source electrode 112 of the first transistor 101 and the signal line 109 are connected. Further, the drain electrode 113 of the first transistor is connected to the gate electrode 107 ′ of the second transistor. Further, the drain electrode 113 ′ of the second transistor is connected to the first current supply line 110. Further, the upper electrode 108 of the capacitor 104 is connected to the first current supply line 110.
[0093]
Next, as the second interlayer insulating film 119, SiN _X A film was formed. The film thickness is 500 nm. A contact hole is provided on the drain electrode 112 'of the second transistor. An Al film having a thickness of 150 nm is formed thereon using a vapor deposition method, and a lower electrode 115 is formed using a photolithographic method.
[0094]
Next, a positive photosensitive protective film (PC452) manufactured by JSR was formed as the third interlayer insulating film 120. A film was formed by a spin coating method under a coating condition of 1000 rpm / 30 seconds, a substrate was placed on a hot plate, and prebaked at 90 ° C./2 minutes.
[0095]
Next, exposure was performed by ghi line mixing using a photomask to form contact holes in stripes. Next, using JSR developer PD-523, development was performed under conditions of room temperature / 40 seconds, and after the development, rinsing was performed with running pure water under conditions of room temperature / 60 seconds. After rinsing, at a wavelength of 365 nm, 300 mJ / cm ² Post-exposure was performed at a strength to obtain a post-baking under conditions of 220 ° C./1 hour with clean opening. The third interlayer insulating film 120 formed of PC452 has a thickness of 1 μm and covers the edge of the lower electrode 115 by 3 μm.
[0096]
Next, the structure of the organic light-emitting element serving as a pixel will be described with reference to FIG. The glass substrate 116 formed up to the lower electrode 115 was subjected to ultrasonic cleaning for 3 minutes in the order of acetone and pure water. After washing and spin drying, it was dried in an oven at 120 ° C. for 30 minutes.
[0097]
Next, a 500 nm Al film 131 and a 20 nm Mo film 132 were sequentially formed by EB vapor deposition. A shadow mask was used for pattern formation. The layer composed of the Al film 131 and the Mo film 132 functions as a light reflecting layer.
[0098]
Next, a LiF film was formed as the electron injection layer 124 on the lower electrode 115.
About 10 mg of the raw material was put in a Mo sublimation boat, and the vapor deposition rate was controlled to 0.05 nm / sec for vapor deposition. For pattern formation, a shadow mask was used and a film thickness of 0.5 nm was deposited. An Alq film having a thickness of 20 nm was formed thereon by vacuum deposition. About 40 mg of the raw material was put in a Mo sublimation boat, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. The Alq film functions as the electron transport layer 123. A co-deposited film of tris (8-quinolinol) aluminum and quinacridone (hereinafter abbreviated as Alq and Qc, respectively) having a film thickness of 20 nm was formed thereon by a binary simultaneous vacuum deposition method. About 40 mg and about 10 mg of Alq and Qc raw materials are put in two Mo sublimation boats, respectively, and the deposition rates are controlled to 0.40 ± 0.05 nm / sec and 0.01 ± 0.005 nm / sec, respectively. And deposited. The Alq + Qc co-evaporated film functions as the light emitting layer 122.
[0099]
Next, a 4,4-bis [N- (1-naphthyl) -N-phenylamino] biphenyl film (hereinafter abbreviated as α-NPD film) having a film thickness of 50 nm was formed by vacuum deposition. About 60 mg of the raw material was put in a Mo sublimation boat, and the vapor deposition rate was controlled to 0.15 ± 0.05 nm / sec. A shadow mask was used for pattern formation. The vapor deposition region was 1.2 times each side of the first electrode. This α-NPD film functions as the hole transport layer 121.
[0100]
Next, an In—Zn—O film (hereinafter abbreviated as IZO film) with a thickness of 50 nm was formed by a sputtering method. This film functions as the upper electrode 125 and is an amorphous oxide film. The target used was In / (In + Zn) = 0.83. The film formation conditions are Ar: O ₂ The atmosphere is mixed gas and the degree of vacuum is 1 Pa. ² It was. The upper electrode 125 made of an In—ZnO film functioned as an anode, and the transmittance was 80%.
[0101]
Next, SiN having a film thickness of 50 nm is formed by sputtering. _X A film was formed. The film functions as a protective layer 126. In the organic light emitting display device of this example, an IZO film was used for the upper electrode 125 in order to extract emitted light from the protective layer side. The IZO film has a sheet resistance of 200Ω / □.
[0102]
In this embodiment, since the light reflection layer formed between the pixels is used as the auxiliary electrode of the upper electrode as in the first embodiment, the wiring resistance value in each pixel is so small that it can be ignored, and there is a variation in luminance within the panel. It is suppressed.
[0103]
(Example 3)
Next, as Example 3 of the present invention, an organic light emitting display device using the upper electrode as an anode will be described with reference to FIG. FIG. 5 is a cross-sectional view taken along the line AA ′ of FIG. In this embodiment, the light reflection layer is formed in a forward tapered shape, and other configurations are substantially the same as those in the first embodiment.
[0104]
The light reflecting layer 130 is formed by the following method.
[0105]
When the third interlayer insulating film 120 is formed, the insulating film layer 140 serving as the base of the light reflecting layer is formed in a mountain shape having a height of 100 nm and a width of 100 nm. Next, a 200 nm Al film and a 20 nm Mo film are formed by EB vapor deposition to form the light reflecting layer 130. Note that a shadow mask was used for pattern formation.
[0106]
In the organic light emitting display device of this embodiment, the light leaked sideways is reflected upward by the reflective layer, thereby preventing crosstalk and improving luminance.
[0107]
Example 4
Next, as Example 4 of the present invention, an organic light emitting display device using the upper electrode as an anode will be described with reference to FIG. 6 is a cross-sectional view taken along the line AA ′ of FIG.
[0108]
In the present embodiment, a light blocking layer 133 is formed on the light reflecting layer 130, and other configurations are substantially the same as those in the first embodiment.
[0109]
The light reflecting layer 130 and the light shielding film 133 are formed by the following method.
[0110]
A 200 nm Al film and a 20 nm Cr film are sequentially formed by EB vapor deposition. A shadow mask was used for pattern formation. At this time, the reflectance of the Cr film is 20% or less and functions as the light shielding film 133. The Al film functions as the light reflecting layer 130.
[0111]
In the organic light emitting display device of the present embodiment, the light leaking from the side is prevented from crosstalk by the light reflecting layer 130, and the light shielding film 133 functions as a black matrix, thereby improving visibility.
[0112]
(Example 5)
Next, as Example 5 of the present invention, an organic light emitting display device using the upper electrode as an anode will be described with reference to FIG. FIG. 7 is a sectional view taken along the line AA ′ of the pixel storage area as in FIG.
[0113]
In this embodiment, a light blocking layer 150 is configured instead of the light reflecting layer 130, and other configurations are substantially the same as those of the first embodiment.
[0114]
The light shielding layer 150 is formed by the following method.
[0115]
A 100 nm Cr film 151, a 100 nm Al film 152, and a 20 nm Mo film 153 are sequentially formed by EB vapor deposition. A shadow mask was used for pattern formation. At this time, the reflectance of the Cr film is 20% or less, and the layer made of Cr / Al / Mo functions as the light shielding layer 150.
[0116]
In the organic light emitting display device of this embodiment, the light leaked by the light shielding layer 150 is absorbed to prevent crosstalk. In this way, the light shielding layer functions as a black matrix, so that the visibility is improved.
[0117]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the dispersion | variation in the brightness | luminance by wiring resistance can be reduced, and the organic light emitting display apparatus of the favorable display which prevents the crosstalk between elements can be provided.
[Brief description of the drawings]
FIG. 1 is a plan view of a pixel region in an organic light-emitting device showing Example 1 of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA ′ shown in FIG.
3A is a schematic diagram illustrating a relationship between a second current supply line and a power supply line in a conventional organic light emitting display device, and FIG. 3B is a diagram illustrating a light reflecting layer in the organic light emitting display device according to the present invention; It is a schematic diagram which shows the relationship with a feeder.
FIG. 4 is a cross-sectional view showing a second embodiment of the present invention.
FIG. 5 is a sectional view showing Example 3 of the present invention.
FIG. 6 is a sectional view showing Example 4 of the present invention.
FIG. 7 is a sectional view showing Example 5 of the present invention.
[Explanation of symbols]
101 ... 1st transistor, 102 ... 2nd transistor, 103 ... Active layer,
104 ... capacitor 105 ... capacitor lower electrode 106 ... scan line 107 ... gate electrode 108 ... capacitor upper electrode 109 ... signal line 110 ... first current supply line 111 ... second current supply line 112,112 '... Source electrode, 113 ... Drain electrode, 114 ... Feed point, 115 ... Lower electrode, 116 ... Substrate, 117 ... Gate insulating film, 118 ... First interlayer insulating film, 119 ... Second interlayer insulating film, 120 ... Third Interlayer insulating film, 121 ... hole transport layer, 122 ... light emitting layer, 123 ... electron transport layer, 124 ... electron injection layer, 125 ... upper electrode, 126 ... protective layer, 130 ... light reflecting layer, 133 ... light shielding film, 140: insulating film layer, 150: light shielding layer.

Claims (19)

In an organic light emitting display device having a plurality of pixels,
Each of the plurality of pixels has an organic light emitting element,
The organic light emitting device is configured to include an organic light emitting layer and an upper electrode and a lower electrode sandwiching the organic light emitting layer, and takes out light emitted from the organic light emitting layer from the upper electrode side.
Both ends of the lower electrode of the organic light emitting element are covered with an insulating film,
The insulating film has a contact hole formed in a stripe shape between adjacent pixels of the plurality of pixels,
A conductive material layer is disposed in the contact holes formed in the stripe shape,
The conductive material layer is disposed so as to reflect light emitted from an organic light emitting layer disposed on at least the lower electrode between the insulating film and electrically connected to the upper electrode of each pixel. Organic light-emitting display devices connected to each other.   2. The organic light emitting display device according to claim 1, wherein the conductive material layer is disposed up to a depth of substantially the same layer position as the organic light emitting layer disposed on the lower electrode.   3. The organic light emitting display device according to claim 2, wherein the conductive material layer is formed of a layer including an Al film.   The conductive material layer is disposed so as to shield light emitted from an organic light emitting layer disposed on at least the lower electrode between the insulating film and the insulating film. Organic light-emitting display device.   3. The organic light emitting display device according to claim 2, wherein the conductive material layer is formed of a layer including a Cr film.   2. The organic light emitting display device according to claim 1, wherein the upper electrode is made of at least one of a transparent conductive oxide, a light-transmissive metal thin film, and an organic conductive film. Said conductive material layer which functions as a light-reflecting layer, an organic light emitting display device according to claim 1 or 3, characterized in that at least one layer having a film of low resistance material than the resistance of the upper electrode. Said conductive material layer which functions as a light-reflecting layer, at least one layer organic light emitting display device according to claim 1 or 3, characterized in that it comprises a film having an alloy containing Mo or Mo. Said conductive material layer which functions as a light-reflecting layer, an organic light emitting display device according to claim 1 or 3, wherein said a material of etch rate different from the etching rate of the lower electrode. Said conductive material layer which functions as a light reflecting layer, said characterized in that it is formed to cover the upper portion of the insulating film according to claim 1 or 3 of the OLED display device. The upper electrode, according to claim 1 or 3 of the organic light emitting display device, characterized in that it is formed on the conductive material layer which functions as a light reflecting layer. It said conductive material layer functioning as a light shielding layer, an organic light emitting display device according to claim 4 or 5, characterized in that at least one layer having a film of low resistance material than the resistance of the material of the upper electrode. It said conductive material layer functioning as a light shielding layer, at least one layer organic light emitting display device according to claim 4 or 5, characterized in that it comprises a film having an alloy containing Mo or Mo. It said conductive material layer functioning as a light shielding layer, an organic light emitting display device according to claim 4 or 5, characterized in that it is made of a material etching rate different from the etching rate of the lower electrode. Said conductive material layer functioning as a light shielding layer, said characterized in that it is formed to cover the upper portion of the insulating film according to claim 4 or 5 of the organic light emitting display device. The upper electrode, according to claim 4 or 5 of the organic light emitting display device, characterized in that it is formed in the conductive reflective layer functioning as a light shielding layer. In an organic light emitting display device having a plurality of pixels,
Each of the plurality of pixels has an organic light emitting element,
The organic light emitting device is configured to include an organic light emitting layer and an upper electrode and a lower electrode sandwiching the organic light emitting layer, and takes out light emitted from the organic light emitting layer from the upper electrode side.
The end of the lower electrode of the organic light emitting device is covered with an insulating film,
The insulating film has a contact hole formed in a stripe shape between adjacent pixels of the plurality of pixels,
A conductive material layer functioning as a light shielding layer is arranged in the contact hole formed in the stripe shape,
The organic light emitting display device in which the conductive material layer functioning as the light shielding layer is electrically connected to the upper electrode of each pixel. The organic light emitting display device according to claim 17 , wherein the conductive material layer is disposed up to a depth of substantially the same layer as the organic light emitting layer disposed on the lower electrode. The organic light emitting display device according to claim 17 , wherein the conductive material layer includes a layer including a Cr film.

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