JP2010033983A - Organic el display device, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL display device having a superior organic compound layer with no effect of burrs and residues formed in formation of the lower layer, and to provide a manufacturing method of the organic EL display device enabling formation of this organic compound layer. <P>SOLUTION: The organic EL display device is composed of the lower part electrode which is constituted of a substrate and a plurality of pixels arranged on the substrate and in which the pixels are installed on the substrate, an electrode layer which is installed upward the lower part electrode and in which the number of the layer is n, and the organic compound layer which is installed between the lower part electrode and the electrode layers directly above the lower part electrode and between the electrode layers, and includes a light-emitting layer to emit prescribed light, and in which the number of the layers is n. The film thickness of the organic compound layer satisfies a relationship of the following equation (1): d<SB>1</SB><d<SB>2</SB>< ..., <d<SB>n</SB>, wherein d<SB>1</SB>denotes the film thickness of a first organic compound layer, d<SB>2</SB>denotes the film thickness of a second organic compound layer, and d<SB>n</SB>denotes the film thickness of an n-th organic compound layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic EL display device and a manufacturing method thereof.

  As a multicolor organic EL display device in which organic compound layers and electrode layers are alternately stacked, for example, a multicolor light emission display device disclosed in Patent Document 1 can be cited. The multicolor light emitting display device disclosed in Patent Document 1 has a configuration in which at least two light emitting elements are stacked, and each light emitting element can be driven individually. Further, in the multicolor light emitting display device disclosed in Patent Document 1, it is necessary to pattern each electrode layer in a desired shape in order to selectively drive a plurality of organic light emitting elements constituting the device. In addition, it is also necessary to partially electrically connect the upper electrode layer to a lower electrode layer or a wiring layer previously formed on the substrate. That is, when the multicolor light emitting display device disclosed in Patent Document 1 is manufactured, a step of selectively removing the electrode layer and the organic compound layer is required. Further, even in the selectively removed region, it is required to sequentially stack the electrode layer and the organic compound layer without causing a short circuit between the electrodes.

US Pat. No. 5,707,745

  However, when the multicolor light emitting display device disclosed in Patent Document 1 is manufactured, particularly when a step of selectively removing the organic compound layer or the electrode layer is performed, burrs or Residues may be generated. For this reason, a favorable processed shape may not be obtained. In particular, as the thickness of the region to be removed increases, burrs and residues may be more prominently generated. When a thin film that becomes an organic compound layer or an electrode layer is formed on a region where burrs or residues are generated in this way, the processed shape in the removed region is not good, so the thin film that becomes an organic compound layer or an electrode layer is good. Hard to form. On the other hand, when the thickness of the organic compound layer formed on the upper layer of the removed region is thin, it is difficult to completely cover the desired region under the influence of burrs and residues generated in the lower layer, and the organic compound layer is good. It becomes difficult to form. For this reason, there is a problem that a short circuit between the electrodes occurs and the manufacturing yield of the organic EL display device is lowered.

  The present invention has been made to solve the above problems. An object of the present invention is to provide an organic EL display device having a good organic compound layer without being affected by burrs and residues generated during the formation of the lower layer, and a method for manufacturing the organic EL display device that enables the formation of this organic compound layer Is to provide.

The organic EL display device of the present invention includes a substrate,
A plurality of pixels arranged on the substrate,
A lower electrode provided on the substrate;
An electrode layer provided above the lower electrode and having n layers;
An organic compound layer including a light emitting layer provided between the lower electrode and the electrode layer immediately above the lower electrode and between the electrode layers and emitting predetermined light, the number of layers being n,
The film thickness of the organic compound layer satisfies the relationship of the following formula (1).
d ₁ <d ₂ <... <d _n (1)
In (Equation (1), d ₁ is .d ₂ representing the thickness of the first organic compound layer, .d _n representing the thickness of the second organic compound layer, the thickness of the n organic compound layer To express.)

  According to the present invention, an organic EL display device having a good organic compound layer without being affected by burrs and residues generated during the formation of the lower layer, and an organic EL display device capable of forming this organic compound layer A manufacturing method can be provided. Therefore, it is possible to reduce a short circuit between the electrodes on the region where the organic compound layer or the electrode layer is selectively removed, and the manufacturing yield of the organic EL display device can be improved.

  The present invention relates to an organic EL display device including a substrate and a plurality of pixels arranged on the substrate, and a manufacturing method thereof.

  The pixel that is a constituent member of the organic EL display device of the present invention is a member that includes a lower electrode, an electrode layer, and an organic compound layer. Here, the lower electrode is provided on the substrate. The electrode layer is provided above the lower electrode, and the number of layers is n. Here, the value of n is preferably 2 to 4 in consideration of the voltage applied to the organic EL display device. The organic compound layer is provided between the lower electrode and the electrode layer immediately above the lower electrode and between the electrode layers, and the number of layers is n. Here, the organic compound layer includes a light emitting layer that emits predetermined light. The value of n is preferably 2 to 4 in consideration of the voltage applied to the organic EL display device.

The organic EL display device of the present invention is characterized in that the film thickness of the organic compound layer satisfies the relationship of the following formula (1).
d ₁ <d ₂ <... <d _n (1)

In Formula (1), d ₁ represents the film thickness of the first organic compound layer. Here, the first organic compound layer refers to an organic compound layer provided between the lower electrode and the first electrode layer provided immediately above the lower electrode.

In the formula (1), d ₂ represents the thickness of the second organic compound layer. Here, the second organic compound layer refers to an organic compound layer provided between the first electrode layer described above and the second electrode layer provided immediately above the first electrode layer.

In the formula (1), d _n represents the film thickness of the n organic compound layer. Here, the nth organic compound layer is an n-1 electrode layer that is the second electrode layer provided from the top and an nth electrode layer (upper electrode) that is the first electrode layer provided from the top. An organic compound layer provided between them.

  When the organic EL display device of the present invention is manufactured, the thickness of the organic compound layer is controlled so as to satisfy the relationship of the above formula (1) when the organic compound layer is formed. That is, as shown in Formula (1), when forming an organic compound layer, it is formed with a film thickness thicker than the organic compound layer below.

In the organic EL display device of the present invention, the light emitting layer included in the organic compound layer preferably satisfies the relationship of the following formula (2).
λ ₁ <λ ₂ <... <λ _n (2)

In Formula (2), λ ₁ represents the peak wavelength of light emitted from the first light emitting layer included in the first organic compound layer.

In Formula (2), λ ₂ represents the peak wavelength of light emitted from the second light emitting layer included in the second organic compound layer.

In Formula (2), λ _n represents the peak wavelength of light emitted from the nth light emitting layer included in the nth organic compound layer.

  In the case of producing the organic EL display device of the present invention, preferably, when the organic compound layer is formed, the light emitting layer included in the organic compound layer satisfies the relationship of the following formula (2). That is, as shown in Formula (2), the peak wavelength of light emitted from the light emitting layer included in the organic compound layer is longer than the peak wavelength of light emitted from the light emitting layer included in the organic compound layer below. It is preferable to adjust so as to shift.

  Hereinafter, the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to this.

[First Embodiment]
FIG. 1 is a schematic view showing an organic EL display device manufactured by the manufacturing method of the present invention. 1, (a) is a schematic cross-sectional view showing an organic EL display device for one pixel, and (b) is a circuit diagram showing an equivalent circuit of the organic EL display device shown in (a).

  An organic EL display device 1 shown in FIG. 1A is a top emission type organic EL display device. In the organic EL display device shown in FIG. 1A, a first subpixel P1, a second subpixel P2, and a third subpixel P3 are arranged in parallel, and the three subpixels P1 are arranged. , P2 and P3 constitute one pixel.

  By the way, in the sub-pixels P1, P2, and P3 shown in FIG. 1A, there are organic compound layers that emit light of different colors between the lower electrode and the electrode layer and between the electrode layer and the electrode layer, respectively. Is formed.

  That is, the first subpixel P1 is formed on the substrate 10 with the lower electrode 11a, the first organic compound layer 12a, the first electrode layer 13a, the second organic compound layer 14a, the second electrode layer 15a, and the third organic compound layer 16a. And the 3rd electrode layer 21 is laminated | stacked in this order.

  A contact hole 20a is provided in the vicinity of the first subpixel P1, so that the first electrode 13a, the second electrode layer 15a, and the third electrode layer 21 can be directly electrically connected. Thereby, the first subpixel P1 forms an equivalent circuit A shown in FIG. 1B, and the first organic compound layer 13a emits light when a desired voltage is applied.

  In the second subpixel P2, the lower electrode 11b, the first organic compound layer 12b, the first electrode layer 13b, the second organic compound layer 14b, the second electrode layer 15b, the third organic compound layer 16b, and the first electrode are formed on the substrate 10. Three electrode layers 21 are laminated in this order.

  A contact hole 18b and a contact hole 20b are provided in the vicinity of the second subpixel P2. Here, the contact hole 18b allows the lower electrode 11b and the first electrode layer 13b to be directly electrically connected. Further, the contact hole 20b allows the second electrode layer 15b and the third electrode layer 21 to be directly electrically connected. By providing the above two types of contact holes, the second subpixel P2 forms the equivalent circuit B shown in FIG. 1B, and the second organic compound layer 14b emits light when a desired voltage is applied. It is supposed to be.

  In the third subpixel P3, the lower electrode 11c, the first organic compound layer 12c, the first electrode layer 13c, the second organic compound layer 14c, the second electrode layer 15c, the third organic compound layer 16c, and the first electrode are formed on the substrate 10. Three electrode layers 21 are laminated in this order.

  A contact hole 19c is provided in the vicinity of the third subpixel P3 so that the lower electrode layer 11c, the first electrode layer 13c, and the second electrode layer can be directly electrically connected. Thus, the third subpixel P3 forms an equivalent circuit C shown in FIG. 1B, and the third organic compound layer 16c emits light when a desired voltage is applied.

  On the other hand, the organic compound layers (12a to 12c, 14a to 14c, and 16a to 16c) shown in FIG. 1A are a single-layer thin film including at least a light-emitting layer or a laminate including two or more layers. Here, when the organic compound layer is a laminate composed of two or more layers, any of a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer and the like is included in addition to the light emitting layer.

  On the other hand, a substrate in which a switching element (not shown) such as a TFT is formed on an insulating substrate may be used as the substrate 10. This switching element is electrically connected to the lower electrodes 11a to 11c.

  Next, the manufacturing method of this invention is demonstrated, referring drawings. FIG. 2 is a schematic cross-sectional view showing a method for manufacturing the organic EL display device of the present invention.

  In the present embodiment, first, the lower electrodes 11a to 11c are patterned in a desired shape on the substrate 10.

  The substrate 10 used in this embodiment is preferably an insulating substrate, for example, a glass substrate.

  Examples of the constituent material of the lower electrodes 11a to 11c include a simple metal such as Cr, Al, and Ag, and a transparent conductive compound such as ITO and IZO. In addition, the 1st electrode layers 11a thru | or 11c may be the laminated body which laminated | stacked the thin film comprised from said metal simple substance, and the thin film comprised from the said transparent conductive compound.

  As a method for forming the lower electrodes 11a to 11c, there is a method in which a metal film or a transparent conductive compound film formed by sputtering or vacuum vapor deposition is patterned using a photolithography method.

  After forming the lower electrodes 11a to 11c, the first organic compound layer 12 common to the plurality of sub-pixels is formed so as to cover the lower electrodes 11a to 11c (FIG. 2A).

When the first organic compound layer 12 is formed, the thickness (d ₁ ) is preferably thin. By forming the first organic compound layer 12 thinner, when forming the contact holes 18b and 18c in the next step, the generation of burrs and residues at the end portions of the formed contact holes 18b and 18c is reduced. Is possible. Here, the film thickness d ₁ is the film thickness of the first organic compound layer provided between the lower electrode and the first electrode layer.

  The first organic compound layer 12 includes, for example, three layers of an electron transport layer, a light emitting layer, and a hole transport layer, but the present invention is not limited to this.

As an electron injecting and transporting material constituting the electron transporting layer, Alq ₃ in which an 8-hydroxyquinoline trimer is coordinated to an aluminum atom, an azomethine zinc complex, a distyrylbiphenyl derivative system, or the like can be used.

  The light-emitting material constituting the light-emitting layer can be appropriately selected according to the color of light to be extracted or the wavelength of light. For example, a triarylamine derivative, a stilbene derivative, a polyarylene, an aromatic condensed polycyclic compound, an aromatic heterocyclic compound, an aromatic heterocyclic condensed ring compound, a metal complex compound, and a single oligo or a composite oligo thereof. Can be used.

  As a hole injecting and transporting material constituting the hole transporting layer, a phthalocyanine compound, a triarylamine compound, a conductive polymer, a perylene compound, an Eu complex, or the like can be used.

  As a method for forming the first organic compound layer 12, a vacuum deposition method, a coating method, or the like can be used.

  Next, the contact holes 18b and 18c are formed by selectively removing the first organic compound layer provided in the region where the contact holes are to be formed (FIG. 2B). At this stage, the first organic compound layer is selectively removed also in regions where contact holes 19a (20a) and 20b, which will be described later, are formed. By this selective removal, the divided first organic compound layers 12a to 12c are formed. As a method for selectively removing the first organic compound layer, a laser ablation method is preferable. Specific examples of the laser ablation method include a method of irradiating a YAG laser, an excimer laser, or the like, but this is not limited as long as the first organic compound layer can be selectively and satisfactorily removed. In this embodiment, more specifically, an excimer laser with a wavelength of 248 nm is used. Further, as a selective removal method of the first organic compound layer, specifically, a method of scanning a laser focused to several μm, a laser is irradiated only to a desired region using a mask in which a light shielding film is arranged in a pattern. A method etc. can be adopted.

  Another method for forming the first organic compound layer 12 and the contact holes 18b and 18c includes pattern formation by vacuum deposition using a metal mask or selective application using an ink jet or the like.

  Next, after forming a thin film corresponding to the first electrode layer on the first organic compound layers 12a to 12c, patterning is performed to form the first electrode layers 13a to 13c divided into desired patterns ( FIG. 2 (c)). At this time, the lower electrode 11b and the first electrode layer 13b are electrically connected via the contact hole 18b. The lower electrode 11c and the first electrode layer 13c are electrically connected through the contact hole 18c. Here, the first electrode layer 13a is formed in a region covering the first organic compound layer 12a. The first electrode layer 13b is formed in a region covering the first organic compound layer 12b. The first electrode layer 13c is formed in a region covering the first organic compound layer 12c.

  The first electrode layers 13a to 13c are preferably transparent electrodes made of ITO, IZO or the like, but may be semi-transparent Al thin films or Ag thin films having a film thickness of 10 nm to 30 nm.

  As a method for forming the first electrode layers 13a to 13c, a method similar to that for the lower electrodes 11a to 11c, that is, a metal film formed by sputtering or vacuum deposition, or a transparent conductive compound film is used by photolithography. And a method of forming a pattern using them.

Next, the second organic compound layer 14 is formed by the same method as that for the first organic compound layer 12 (FIG. 2C). Here, the film thickness (d ₂ ) of the second organic compound layer 14 is made larger than the film thickness d _{1 of} the first organic compound layer 12. By making the film thickness of the second organic compound layer 14 larger than that of the first organic compound layer 12, a thin film corresponding to the second organic compound layer 14 is also formed on the first electrode layer 13b formed on the contact hole 18b. It can be formed satisfactorily. For this reason, generation | occurrence | production of the short circuit between the 1st electrode layer 13b and the 2nd electrode layer 15b mentioned later can be reduced. Here, the film thickness d ₂ means the film thickness of the second organic compound layer provided between the first electrode layer and the second electrode layer.

  The second organic compound layer 14 includes, for example, three layers of an electron transport layer, a light emitting layer, and a hole transport layer, but the present invention is not limited to this. Further, as the constituent material of the second organic compound layer 14, the same material as the constituent material of the first organic compound layer 12 can be used.

  As a method for forming the second organic compound layer 14, as in the case of the first organic compound layer 12, a vacuum deposition method, a coating method, and the like can be given.

  Next, the contact holes 19a and 19c are formed by selectively removing the second organic compound layer provided in the region where the contact holes are to be formed (FIG. 2D). At this stage, the second organic compound layer is selectively removed also in a region where a contact hole 20b described later is formed. By this selective removal, the divided second organic compound layers 14a to 14c are formed.

  Next, after forming a thin film corresponding to the second electrode layer on the second organic compound layers 14a to 14c, patterning is performed to form second electrode layers 15a to 15c divided into desired patterns ( FIG. 2 (e)). At this time, the first electrode layer 13a and the second electrode layer 15a are electrically connected through the contact hole 19a. Further, the lower electrode 11c, the first electrode layer 13c, and the second electrode layer 15c are electrically connected through the contact hole 19c. Here, the second electrode layer 15a is formed in a region covering the second organic compound layer 14a. The second electrode layer 15b is formed in a region covering the second organic compound layer 14b. The second electrode layer 15c is formed in a region covering the second organic compound layer 14c.

  The second electrode layers 15a to 15c are preferably transparent electrodes made of ITO, IZO or the like, but may be semi-transparent Al thin films or Ag thin films having a film thickness of 10 nm to 30 nm.

  As a method of forming the second electrode layers 15a to 15c, a method similar to that of the lower electrodes 11a to 11c, that is, a metal film formed by sputtering or vacuum deposition, or a transparent conductive compound film is used by photolithography. And a method of forming a pattern using them.

Next, the third organic compound layer 16 is formed by the same method as that for the first organic compound layer 12 (FIG. 2E). Here, the film thickness (d ₃ ) of the second organic compound layer 16 is made larger than the film thickness d _{2 of} the second organic compound layer 14. By making the film thickness of the third organic compound layer 16 larger than that of the second organic compound layer 14, a thin film corresponding to the second organic compound layer 14 is also formed on the second electrode layer 15b formed on the contact hole 19c. It can be formed satisfactorily. For this reason, generation | occurrence | production of the short circuit between the 2nd electrode layer 15c and the 3rd electrode layer 21 mentioned later can be reduced. Further, when the second electrode layers 15 a to 15 c are formed by patterning or the like, burrs or residues may be generated at the processed end, but the film of the third organic compound layer 16 is more than the second organic compound layer 14. The thickness may be increased. By doing so, a film efficiently covering the second electrode layers 15a to 15c can be formed. Note that the film thickness d ₃ referred to herein is intended to refer to a film thickness of the third organic compound layer provided between the second electrode layer and the third electrode layer.

  The third organic compound layer 16 includes, for example, three layers of an electron transport layer, a light emitting layer, and a hole transport layer, but is not limited to this in the present invention. Further, as the constituent material of the third organic compound layer 16, the same material as the constituent material of the first organic compound layer 12 can be used.

  As a method for forming the third organic compound layer 16, as in the case of the first organic compound layer 12, a vacuum deposition method, a coating method, and the like can be given.

  Next, the contact holes 20a and 20b are formed by selectively removing the third organic compound layer provided in the region for forming the contact holes (FIG. 2 (f)). By this selective removal, divided third organic compound layers 16a to 16c are formed.

  Next, the third electrode layer 21 is formed on the third organic compound layers 16a to 16c (FIG. 2G). At this time, the first electrode layer 13a, the second electrode layer 15a, and the third electrode layer 21 are electrically connected through the contact hole 20a. The second electrode layer 15b and the third electrode layer 21 are electrically connected through the contact hole 20b.

  The third electrode layers 15a to 15c are preferably transparent electrodes made of ITO, IZO or the like, but may be semi-transparent Al thin films or Ag thin films having a film thickness of 10 nm to 30 nm.

  Examples of the method for forming the third electrode layer 21 include a sputtering method and a vacuum deposition method.

  The organic EL display device manufactured by the method described above can satisfactorily form the organic compound layer even on the region where the organic compound layer or the electrode layer has been selectively removed. Accordingly, it is possible to reduce a short circuit between the electrode layers that may occur on the region where the organic compound layer or the electrode layer is selectively removed, and to improve the manufacturing yield of the organic EL display device.

[Second Embodiment]
In the method for producing an organic EL display device of the present invention, preferably, the emission peak wavelength of the light emitting layer contained in the organic compound layer is longer than the emission peak wavelength of the light emitting layer contained in the organic compound layer below. Adjust to shift.

  Specifically, for example, in the organic EL display device of FIG. 1A, the emission spectrum of the second light emitting layer included in the second organic compound layers (14a to 14c) is the first organic compound layer (12a to 12c). It is preferable that the wavelength is longer than the emission spectrum of the first light-emitting layer included in (1). Moreover, the emission spectrum of the 3rd light emitting layer contained in a 3rd organic compound layer (16a-16c) is longer wavelength than the light emission spectrum of the 2nd light emitting layer contained in a 2nd organic compound layer (14a-14c). Is preferred.

  More specifically, for example, in the organic EL display device of FIG. 1A, the first light emitting layer included in the first organic compound layers (12a to 12c) is a blue light emitting layer. And let the 2nd light emitting layer contained in a 2nd organic compound layer (14a-14c) be a green light emitting layer, and let the 3rd light emitting layer contained in a 3rd organic compound layer (16a-16c) be a red light emitting layer.

  By doing so, it becomes possible to extract light with high color purity using the resonator structure of light, and the display quality of the organic EL display device can be further improved.

It is a schematic diagram which shows the organic electroluminescence display manufactured by the manufacturing method of this invention, (a) is a cross-sectional schematic diagram which shows the organic electroluminescence display for 1 pixel, (b) is (a). It is a circuit diagram which shows the equivalent circuit of the organic electroluminescence display shown. FIG. 2 is a schematic cross-sectional view showing a method for manufacturing the organic EL display device of the present invention.

Explanation of symbols

10 Substrate 11a, 11b, 11c Lower electrode 12, 12a, 12b, 12c First organic compound layer 13a, 13b, 13c First electrode layer 14, 14a, 14b, 14c Second organic compound layer 15a, 15b, 15c Second electrode Layer 16, 16a, 16b, 16c Third organic compound layer 18b, 18c, 19a, 19c, 20a, 20b Contact hole 21 Third electrode layer P1 First subpixel P2 Second subpixel P3 Third subpixel

Claims (4)

A substrate,
A plurality of pixels arranged on the substrate,
A lower electrode provided on the substrate;
An electrode layer provided above the lower electrode and having n layers;
An organic compound layer including a light emitting layer provided between the lower electrode and the electrode layer immediately above the lower electrode and between the electrode layers and emitting predetermined light, the number of layers being n,
An organic EL display device, wherein the film thickness of the organic compound layer satisfies the relationship of the following formula (1).
_{d 1 <d 2 <··· <} d n (1)
In (Equation (1), d ₁ is .d ₂ representing the thickness of the first organic compound layer, .d _n representing the thickness of the second organic compound layer, the thickness of the n organic compound layer To express.) The organic EL display device according to claim 1, wherein the light emitting layer included in the organic compound layer satisfies a relationship of the following formula (2).
λ ₁ <λ ₂ <... <λ _n (2)
(In Formula (2), λ ₁ represents the peak wavelength of light emitted from the first light-emitting layer included in the first organic compound layer. Λ ₂ is emitted from the second light-emitting layer included in the second organic compound layer. .λ represents a peak wavelength of light _n represents a peak wavelength of light emitted from the n light emitting layer included in the n organic compound layer.) A substrate,
A plurality of pixels arranged on the substrate,
A lower electrode provided on the substrate;
An electrode layer provided above the lower electrode and having n layers;
An organic compound layer including a light emitting layer provided between the lower electrode and the electrode layer immediately above the lower electrode and between the electrode layers and emitting predetermined light, the number of layers being n;
In the manufacturing method of the organic EL display device comprising:
A method for producing an organic EL display device, comprising controlling the film thickness of the organic compound layer so as to satisfy the relationship of the following formula (1) when the organic compound layer is formed.
d ₁ <d ₂ <... <d _n (1) 4. The method of manufacturing an organic EL display device according to claim 3, wherein when the organic compound layer is formed, the light emitting layer included in the organic compound layer satisfies a relationship of the following formula (2).
λ ₁ <λ ₂ <... <λ _n (2)

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