JP2008108680A - Manufacturing method of organic EL element - Google Patents

Description

  The present invention relates to a method for manufacturing an organic EL element, and in particular, an organic EL element in which an inorganic insulating film that improves a reduction in visibility caused by generation of a leak current through the organic EL layer is formed on the organic EL layer. It relates to the manufacturing method.

  As an example of a light-emitting element applied to a display device, an organic electroluminescent element (hereinafter, also referred to as “organic EL element”) having a thin film laminated structure of an organic compound is known. This organic EL element is applied to a wide range of screen display devices such as portable terminals, industrial measuring instruments, and home televisions.

  The organic EL element is a thin-film self-luminous element and has excellent properties such as a low driving voltage, a high resolution, and a high viewing angle. For this reason, various studies have been made to specifically put these properties into practical use.

  An organic EL element is a laminate having a structure in which at least an organic light emitting layer is provided between an anode and a cathode, and a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer are interposed as required. is there. In such a structure, when a voltage is applied between the anode and the cathode, the injected holes and electrons recombine in the organic light emitting layer, resulting in a transition from the high energy state to the ground state. Sometimes light is emitted.

  Various displays have been developed that realize such a display function by arranging organic EL elements having such light emitting modes in a matrix. There are various driving methods for the light emitting section (the part corresponding to the pixel in the case of monochrome display, the part corresponding to the sub-pixel in the case of color display), but the anode row and the cathode row are orthogonal to each other. A method called passive matrix drive, which is relatively simple in configuration, is often used. In a passive matrix drive display, anodes and cathodes are arranged in a plurality of stripes in a state of being orthogonal to each other, and light emitting portions where the anode rows and the cathode rows intersect with each other emit light by selecting specific signals and are displayed. .

  In recent years, low power consumption has become an important issue for the above displays. For this reason, various contrivances have been made, and among them, efforts aimed at lowering the light emission threshold voltage are being actively conducted.

  That is, in order to lower the resistance value of a hole injection layer, a hole transport layer, an electron transport layer, or the like, which is a layer that injects or transports holes or electrons, F4- It is widely practiced to dope an acceptor typified by a Lewis acid compound such as TCNQ, and to dope a donor typified by an alkali metal such as Li to the electron transport layer.

  As a result, it has been confirmed that the electrical conductivity is improved by 2 to 3 orders of magnitude by doping 1 wt% of F4-TCNQ into the hole injection layer and the hole transport layer. It has also been confirmed that the electrical conductivity is improved by 1 to 2 digits by doping Li in the electron transport layer by 25 wt%. These improvements in electrical conductivity lower the emission threshold voltage, which was 20 V or more in the case of non-doping, to 10 V or less.

  Such an organic EL display that has been studied to reduce power consumption includes many thin film elements. For this reason, on the structure of a thin film element, generation | occurrence | production of the leakage current through an organic EL layer cannot be disregarded, and suppression of leakage current is an important subject. The occurrence of the leakage current causes a phenomenon in which light emitting portions other than the light emitting portion desired to emit light, that is, so-called crosstalk.

  The following are disclosed as techniques for preventing or suppressing leakage current.

  Japanese Patent Laid-Open No. 3-250583 (Patent Document 1) includes a lower electrode provided on a substrate, an organic multilayer part including a light emitting layer, and an element composed of a counter electrode as a light emitting element part. There is disclosed an electroluminescence element including a non-light emitting element portion in which a patterned interlayer insulating film is present.

  Japanese Patent Laid-Open No. 4-51494 (Patent Document 2) includes a plurality of a pair of electrodes facing each other and an organic electroluminescence layer disposed between the electrodes, and the organic electroluminescence layer and at least one of the electrodes An electroluminescent device is disclosed that includes an insulating layer sandwiched therebetween and extending along an edge of the electrode.

  In the techniques disclosed in these Patent Documents 1 and 2, an anode array is formed in a stripe pattern on a substrate, and an interlayer insulating film is formed between the anode arrays, whereby an anode and a cathode are formed. Can be prevented. However, in these techniques, since the organic EL layer is formed over the entire surface of the substrate on the interlayer insulating film, a weak leakage current may be generated through the organic film.

  JP-A-8-315981 (Patent Document 3) discloses a substrate in which a plurality of first display electrodes corresponding to a light emitting portion are formed on a surface, and at least a part of the first display electrode is exposed. A plurality of electrically insulating barrier ribs projecting on the substrate; at least one organic electroluminescent medium thin film formed on each of the exposed portions of the first display electrode; and formed on the medium thin film. Further, there is disclosed a display panel comprising a plurality of second display electrodes and having an overhang portion protruding in a direction parallel to the substrate above the partition wall.

  FIG. 3 is a schematic view showing the structure of the organic EL element disclosed in Patent Document 3, wherein (a) is a cross-sectional view along the longitudinal direction of the cathode 27, passing through the center of the light emitting part, ) Is a cross-sectional view along the longitudinal direction of the anode 22 through the center of the light emitting part. As shown in FIG. 3, in this organic EL element, the anode 22 is formed in a stripe shape on the substrate 21, and the interlayer insulating film 23 is formed on the entire surface of the substrate 21 except for the opening for the light emitting portion. A hole transport layer 24, an organic light emitting layer 25, and an electron transport layer 26 are sequentially formed so as to cover all the openings, and are in a direction perpendicular to the stripe of the anode 22, and the organic EL layers 24- 26 has a structure in which a cathode 27 is formed, and on the interlayer insulating film 23, a partition wall 28 is formed which is partially widened upward in a sectional view in the longitudinal direction of the anode 22.

  In such an organic EL element, since the partition wall 28 is disposed between each stacked group including the stacked organic EL layers 24 to 26 and the cathode 27, these stacked groups 24 to 27 are in contact with each other. There is nothing (FIG. 3B). However, in the longitudinal direction of the partition wall 28, for example, the highly conductive hole transport layer 24 or the like may be a path for leakage current (FIG. 3A).

  Further, JP-A-3-2333891 (Patent Document 4) comprises a plurality of electrode pairs facing each other and an electroluminescence layer disposed between the electrode pairs, and the electroluminescence layer is sandwiched between the electrode pairs. In other words, an electroluminescent element is disclosed, which includes island region groups that exist independently in each of the plurality of regions.

  Japanese Patent Laid-Open No. 2000-36388 (Patent Document 5) includes a first electrode made of a transparent conductive material, an organic layer having at least a layer made of an organic light emitting material, and a metal or alloy on a transparent substrate. An optical element is disclosed in which a second electrode is formed in this order, and a plurality of the organic layers are provided in an island-like state.

  Both of the techniques disclosed in Patent Documents 4 and 5 disclose forming an organic EL layer in an island shape. FIG. 4 is a schematic view showing the structure of the organic EL element disclosed in Patent Documents 4 and 5, wherein (a) is a cross-sectional view along the longitudinal direction of the cathode 37, passing through the center of the light emitting part, (B) is a cross-sectional view along the longitudinal direction of the anode 32 through the center of the light emitting section. As shown in FIG. 4, in this organic EL element, anodes 32 are formed in stripes on a substrate 31, and an interlayer insulating film 33 is formed on the entire surface of the substrate 31 except for an opening for a light emitting portion. The hole transport layer 34, the organic light emitting layer 35, and the electron transport layer 36 are sequentially formed almost only on the opening, and are in a direction orthogonal to the stripe of the anode 32 and the organic EL layers 34 to 36. Has a structure in which a cathode 37 is formed so as to cover completely from above.

  In such an organic EL element, since the organic EL layers 34 to 36 are formed in an island shape, there is no leakage current path via the adjacent highly conductive charge transport layers 34 and 36 (FIG. 4A). (B)). However, since the cathode 37 has a structure in which the gap between the island-shaped organic EL layers 34 to 36 is filled in order to realize passive matrix driving, the cathode 37 and the highly conductive hole transport layer 34 or electron transport layer 36. There is a risk that the contact surface will be a path for leakage current (FIG. 4A).

  In addition, Japanese Patent Application Laid-Open No. 2005-276667 (Patent Document 6) discloses an insulating substrate, a plurality of first electrodes disposed on the substrate at intervals, and these first electrodes. An organic compound layer including at least a light-emitting layer formed in a state of covering from above, and a second electrode disposed so as to cross and face the first electrode with the organic compound layer interposed therebetween, An organic EL element is disclosed in which an organic compound layer is divided between the plurality of first electrodes, and an insulating layer is embedded in the divided portion so that an end face of the organic compound layer is not exposed. Has been.

  In the technique disclosed in Patent Document 6, there is a possibility that a predetermined shape on the surface of the organic EL layer cannot be obtained due to mask displacement when forming an insulating layer filling the organic layer. In such a case, a leakage current from the cathode to the anode that is not planned via the organic EL layer may occur.

Japanese Patent Laid-Open No. 3-250583 JP-A-4-51494 JP-A-8-315981 JP-A-3-2333891 JP 2000-36388 A JP 2005-276667 A JP 9-167684 A

  Accordingly, the object of the present invention is to ensure superiority over the technologies disclosed in Patent Documents 1 to 6, particularly when an insulating layer is disposed between the organic EL layers, and Another object of the present invention is to provide a method for producing an organic EL device in which the contact surface between the cathode and the charge transport layer does not become a path for leakage current.

  In manufacturing an organic EL element driven by a passive matrix, the present invention forms an anode array by disposing a plurality of electrode layers on an insulating substrate in a state of being separated from each other, and at least holes are formed on the anode array. A step of forming an organic EL layer by laminating a transport layer, an organic light emitting layer, an electron transport layer, and a metal thin film in an island shape, and further forming an inorganic insulating film so as to cover the island-shaped organic EL layer from above And a step of exposing the inorganic thin film to expose the metal thin film, a plurality of the metal thin film and the inorganic insulating film being spaced apart from each other and orthogonal to the anode row. And a step of forming a cathode column by arranging an electrode layer. In the organic EL manufacturing method of the present invention, the portion including the organic EL layer is a light emitting portion, and this light emitting portion corresponds to a pixel in the case of monochrome display, and in the case of color display. This is a portion corresponding to a sub-pixel.

  The manufacturing method of the organic EL element of this invention can be used in order to obtain the structural member of the display apparatus which has the outstanding visibility. In the method for producing an organic EL device of the present invention, the charge transport layer is preferably at least one of a hole transport layer and an electron transport layer. The etching process is preferably a dry etching process, a photo etching process, or a laser etching process.

  In the method for producing an organic EL element of the present invention, the contact surface between the organic EL layer and / or the cathode and the charge transport layer cannot be a path for leakage current. For this reason, according to the method, an organic EL element having excellent visibility can be obtained. As a result, the organic EL element is highly visible in recent years, such as portable terminals, industrial measuring instruments, and home televisions. The present invention can be applied to various screen display devices that are increasingly demanded for their characteristics.

Hereinafter, preferred embodiments of the present invention will be described in detail, but this is an example of the present invention, and the present invention is not particularly limited to this example.
FIG. 1 is a cross-sectional view along the longitudinal direction of a cathode showing a method for producing a passive matrix driven organic EL device of the present invention, wherein (a) is a first step until an inorganic insulating film is formed, (b). Shows a second step of etching the inorganic insulating film, and (c) shows a third step of forming the cathode. FIG. 2 is a cross-sectional view along the longitudinal direction of the anode showing the method for manufacturing an organic EL element driven by a passive matrix according to the present invention. (A), (b), and (c) are respectively diagrams. It is drawing corresponding to 1 (a), (b), and (c). Hereinafter, although each process is demonstrated in detail, in the following description, an example of the manufacturing method regarding a bottom emission type organic EL element is shown among organic EL elements.

(First step)
In the first step, as shown in FIGS. 1A and 2A, an anode 12, an interlayer insulating film 13, an organic layer (a hole transport layer 14, an organic light emitting layer 15, and an electron transport) are formed on a substrate 11. In this step, the layer 16) and the metal thin film 17 are sequentially formed, and the inorganic insulating film 18 is formed so as to cover the organic layers 14 to 16 from above.

  The board | substrate 11 will not be specifically limited if it is excellent in visible light transmittance | permeability. For example, a glass substrate, various plastic substrates or various films can be used.

As the anode 12, an amorphous transparent conductive film, for example, IZO or ITO can be used. As the interlayer insulating film 13, SiO _x , SiN _x, or the like formed by a CVD method using a positive photoresist [WIX-2A] (trade name, manufactured by Nippon Zeon Co., Ltd.) can be used.

  As the organic layer, as shown in FIGS. 1 (a) and 2 (a), it is important to use at least a hole transport layer 14, an organic light emitting layer 15, and an electron transport layer 16. In addition, a hole injection layer and an electron injection layer (not shown in FIGS. 1 and 2) may be provided. The arrangement of the hole injection layer is preferable from the viewpoint of improving the hole injection efficiency, and the arrangement of the electron injection layer is preferable from the viewpoint of improving the electron injection efficiency.

  The material of each layer of the organic layer is not particularly limited, and known materials can be used. The hole transport layer 14 may be made of MTDATA as a base material and doped with a Lewis oxide such as F4-TCNQ. The doping amount of the Lewis oxide is preferably 0.5 to 5 wt% with respect to the hole transporting material.

  A material corresponding to a desired color tone can be selected for the organic light emitting layer 15. For example, in order to obtain light emission from blue to blue green, a material such as benzothiazole, benzimidazole, or benzoxazole is used. An optical brightener, a styrylbenzene compound, an aromatic dimethylidin compound, or the like can be used. Note that white light emission can also be obtained by simultaneously dispersing a blue guest material and a red guest material in the host material of the organic light emitting layer 15.

  As host materials, aluminum chelate, 4,4′-bis (2,2′-diphenylvinyl) biphenyl (DPVBi), and 2,5-bis (5-tert-butyl-2-benzoxazolyl) -thiophene (BBOT) or the like can be used.

  Blue guest materials include perylene, 2,5,8,11-tetra-t-butylperylene (TBP), 4,4′-bis [2- {4- (N, N-diphenylamino) phenyl} vinyl Biphenyl (DPAVBi) or the like can be doped by 0.1 to 5 wt%.

  As the red guest material, 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran (DCM), 4,4-difluoro-1,3,5,7-tetraphenyl -4-Bora-3a, 4a, -diaza-s-indacene, propanedinitrile (DCJT1), Nile Red, etc. can be doped by 0.1 to 5 wt%.

  The electron transport layer 16 may be made of (aluminum chelate) Alq3 as a base material and doped with an alkali metal such as Li. The doping amount of the alkali metal is preferably 1 to 40 wt% with respect to the electron transporting material.

  The metal thin film 17 is used for protecting the organic layers 14 to 16 and ensuring good contact with the cathode 19 described later. For the metal thin film 17, Al, Ag, MgAg, AlLi, or the like can be used.

The inorganic insulating film 18 is used to improve a problem in the prior art, that is, a problem related to a decrease in visibility caused by the occurrence of a leak current through the organic EL layer. For the inorganic insulating film 18, silicon oxide (SiO _X ), silicon nitride (SiN _X ), silicon oxynitride (SiO _X N _Y ), or the like can be used.

  Next, the substrate 11, the anode 12, the organic layer (the hole transport layer 14, the organic light emitting layer 15, and the electron transport layer 16), the metal thin film 17, and the inorganic insulating film 18 described above are used. One step will be described in detail.

  First, an anode material is formed on the cleaned substrate 11 by a method such as vapor deposition or sputtering, and patterned into a stripe shape by photoetching to form the anode 12. The anode 12 is an anode row composed of a plurality of striped electrodes that are spaced apart from each other in parallel.

  Next, an interlayer insulating film 13 is formed on the entire surface of the substrate on the patterned anode 12 except for a portion to be a light emitting portion. For this formation, for example, a technique such as an etching method using a photoresist or a dry etching method can be used.

  Further, the organic layers 14 to 16 are sequentially formed in an island shape in the opening formed by the interlayer insulating film 13. Here, the island shape means a state in which a plurality of organic layers 14 to 16 exist discontinuously in both the longitudinal direction of the anode 12 and the longitudinal direction of the cathode 19.

  A vacuum deposition method using a mask can be used for island formation of these organic layers 14-16. In addition, as disclosed in Japanese Patent Laid-Open No. 9-167684 (Patent Document 7), the island formation is performed by arranging a donor sheet on which an organic EL material has been formed in advance on the substrate so as to be spaced apart from each other. It is also possible to irradiate the substrate with a heat source such as a laser and deposit an organic EL material on the substrate.

  About the film thickness in each layer of the organic layers 14-16, a drive voltage, transparency, etc. can be selected suitably. Specifically, for example, the hole transport layer 14 may be 20 to 80 nm, the organic light emitting layer 15 may be 20 to 40 nm, and the electron transport layer 16 may be 20 to 40 nm.

  Subsequently, a metal thin film 17 is formed on the organic layers 14 to 16 formed in an island shape. Examples of the formation method include a mask vapor deposition method and a proximity separation formation method.

  Finally, the inorganic insulating film 18 is formed by CVD or sputtering so that all of the island-shaped organic layers 14 to 16 and the metal thin film 17 are covered from above and the upper surface of the interlayer insulating film 13 is an outer edge in plan view. Form by law. By the formation of the inorganic insulating film 18, the island portions formed of the organic layers 14 to 16 and the metal thin film 17 are completely insulated (FIGS. 1A and 2A). The metal thin film 17 is effective as a protective film for preventing damage to the organic layers 14 to 16 when the inorganic insulating film 18 is formed.

(Second step)
In the second step, as shown in FIG. 1B and FIG. 2B, the inorganic insulating film 18 located at the uppermost part of the laminate obtained in the first step is subjected to an etching process to form a metal thin film 17. As a result, the entire inorganic insulating film 18 is removed to the same level as the exposed metal thin film 17 so as to be flush with each other.

  The etching process is preferably a dry etching process, a photo etching process, or a laser etching process.

  In these etching processes, the metal thin film 17 serves as a protective film for the organic layers 14 to 16, in other words, as an etching stop layer. In the second step, as shown in FIGS. 1 (b) and 2 (b), the exposure of the surface of the metal thin film is reliably achieved, and contact with the cathode 19 described later can be realized without problems, and the peripheral portion of the metal thin film In this case, since the inorganic insulating film is not over-etched, leakage due to contact between the cathode and the organic film can be prevented. This is necessary to form the cathode 19 described later with high accuracy.

(Third step)
In the third step, as shown in FIG. 1C and FIG. 2C, a cathode 19 is formed on the metal thin film 17 and the inorganic insulating film 18 located at the top of the laminate obtained in the second step. It is a process of forming.

  The cathode 19 is made of a metal material, and for example, Al, Ag, MgAg, AlLi, or the like can be used.

  Formation of the cathode 19 can use methods, such as a vapor deposition method, for example.

  After the cathode 19 is formed in this manner, the substrate 11, the anode 12, the interlayer insulating film 13, the organic layer (the hole transport layer 14, the organic light emitting layer) shown in FIGS. 1C and 2C. 15 and an electron transport layer 16), a laminate comprising a metal thin film 18, an inorganic insulating film 18 and a cathode 19 are placed in a glove box (not shown), and in a dry nitrogen atmosphere in which both oxygen and moisture concentrations are 10 ppm or less, Sealing is performed using sealing glass and a UV curable adhesive.

  In the organic EL element obtained through each of the first to third steps as described above, the organic layers 14 to 16 and the metal thin film 17 are formed in an island shape, in other words, the anode 12 The layer groups 14 to 17 are discontinuously arranged in the cross section along the longitudinal direction (FIG. 1C) and also in the cross section along the longitudinal direction of the cathode 19 (FIG. 2C). In addition, an inorganic insulating film 18 is disposed between the island portions. For this reason, in the organic EL element obtained by the manufacturing method of the present invention, the contact surface between the organic EL layer and / or the cathode and the charge transport layer does not become a path of leakage current. Therefore, the organic EL element obtained in this manner can exhibit excellent visibility, and as a result, the organic EL layer has recently been high in portable terminals, industrial measuring instruments, home televisions, and the like. It can be applied to various screen display devices for which visibility is increasingly demanded.

Hereinafter, the present invention will be described in detail with reference to examples, and the effects of the present invention will be demonstrated.
(Formation of organic EL elements)
Example 1
A VGA standard (400 × RGB × 300) display including the organic EL element of the present invention shown in FIGS. The RGB subpixel size was 0.148 × 0.704 mm, and the subpixel spacing was 0.130 mm. The pixel size was 0.704 mm × 0.704 mm, and the pixel interval was 0.312 mm. The pixel pitch was 1.016 mm.

A display portion (400 × RGB × 300) having the above pixel configuration was formed on a glass substrate of 500 mm × 500 mm × 0.50 mm. The manufacturing method is as follows.
That is, first, an anode material (transparent electrode (ITO) material) was formed on the entire surface of a glass substrate by sputtering. Next, after applying a resist agent “OFRP-800” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) on the anode material, patterning is performed by a photolithography method, and the width is 0.204 mm and the gap 0 is located in the RGB sub-pixel portion. A stripe-patterned anode having a thickness of 0.048 mm and a thickness of 100 nm was obtained.

  Next, using a positive photoresist “WIX-2A” (trade name, manufactured by ZEON CORPORATION), an opening of 0.148 × 0.704 mm is left at the position corresponding to the subpixel on the anode, and the thickness is 1 μm. An interlayer insulating film was formed. The angle with respect to the substrate at the end of the interlayer insulating film was an acute angle.

Further, the substrate on which the anode and the interlayer insulating film are formed is placed in a resistance heating vapor deposition apparatus, and using a mask having an opening of 0.148 × 0.704 mm size in the sub-pixel corresponding portion, a hole transport layer, The organic light emitting layer and the electron transport layer were sequentially formed in an island shape without breaking the vacuum. During film formation, the internal pressure of the vacuum chamber was 1 × 10 ⁻⁴ Pa.

  As the hole transporting layer, 20 nm of MTDATA doped with 1 wt% of F4-TCNQ was formed. As the organic light emitting layer, a host material 4,4′-bis (2,2′-diphenylvinyl) biphenyl (DPVBi) and a blue guest material 4,4′-bis [2- {4- (N, N-diphenyl) are used. Amino) phenyl} vinyl] biphenyl (DPAVBi) doped with 5 wt% was deposited to a thickness of 40 nm. As the electron transport layer, an aluminum chelate (Alq3) doped with 25 wt% of Li was deposited to a thickness of 20 nm. Next, a metal thin film made of Al having a thickness of 20 nm was formed without breaking the vacuum.

The thus obtained substrate in which the layer group consisting of the island-like organic layer and the metal thin film is arranged in a matrix is placed in a CVD apparatus, and each flow rate of SiH ₄ 100 sccm, NH ₃ 500 sccm, and N ₂ 5000 sccm is set. The pressure is kept at 0.75 torr, glow discharge is performed with a discharge frequency of 13.56 WHz and a discharge power of 500 W, and the gap between the island-like layers is filled, and a 200 nm thick SiN film is formed on the metal thin film. An insulating film was formed.

  On the formed inorganic insulating film, a resist film was applied using the portion corresponding to the sub-pixel portion as an opening, and dry etching was performed using the metal thin film as an etching stop layer to expose the surface of the metal thin film. At this time, the levels of the metal thin film and the inorganic insulating film were controlled to be the same.

  After the resist was peeled off, an exposed metal thin film was covered by a vapor deposition method using a mask, and an Al film was stacked as a cathode in a direction perpendicular to the anode row to form a cathode row.

  Finally, a laminate composed of a substrate, an anode, an interlayer insulating film, an organic layer (a hole transport layer, an organic light emitting layer, and an electron transport layer), a metal thin film, an inorganic insulating film, and a cathode is placed in a glove box, In a dry nitrogen atmosphere in which oxygen and moisture concentrations are both 10 ppm or less, sealing was performed using sealing glass and a UV curable adhesive to obtain an organic EL element, which was arranged in a matrix to obtain a display. .

(Example 2)
As a material used for the organic light emitting layer, 4,4′-bis (2,2′-diphenylvinyl) biphenyl (DPVBi) is used as a host material, and 4,4′-bis [2- {4- (N, N-diphenylamino) phenyl} vinyl] biphenyl (DPAVBi) and 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran (DCM) as a red guest material The display of VGA standard (400 × RGB × 300) was produced under the same conditions as in Example 1 except that a 40 nm white light emitting layer was formed. The DPAVBi and DCM were respectively doped with 2.5 wt% and 0.2 wt% with respect to the host material.

(Example 3)
A VGA standard (400) under the same conditions as in Example 1 except that instead of dry etching, the inorganic insulating film (SiN film) corresponding to the subpixel was etched using a laser beam to expose the surface of the metal thin film. A display of × RGB × 300) was produced.

(Comparative example)
According to the example shown in Patent Document 3 (FIG. 3), an organic EL element was formed, and the subsequent process was performed in the same manner as in Example 1 to obtain a display.
Specifically, the same manufacturing process as in Example 1 was applied until an interlayer insulating film was formed, and then a 4 μm thick partition wall using a negative photoresist [ZPN1100] (trade name, manufactured by Nippon Zeon) Formed. The partition length in the longitudinal direction of the cathode was 130 μm, and the partition pitch was 1.016 mm.

Further, the substrate on which the anode was formed was placed in a resistance heating vapor deposition apparatus, and a hole transport layer, an organic light emitting layer, and an electron transport layer were sequentially formed without breaking the vacuum. During film formation, the internal pressure of the vacuum chamber was 1 × 10 ⁻⁴ Pa. For the hole transport layer, MTDATA having a thickness of 20 nm formed by doping 1 wt% of F4-TCNQ was formed. For the organic light emitting layer, the host material 4,4′-bis (2,2′-diphenylvinyl) biphenyl (DPVBi) and the guest material 4,4′-bis [2- {4- (N, N-diphenylamino)] [Phenyl} vinyl] biphenyl (DPAVBi) was doped to form a 40 nm film. For the electron transport layer, an aluminum chelate (Alq3) doped with 25 wt% of Li was formed to a thickness of 20 nm. Subsequently, using a metal mask, a cathode made of an Al layer having a thickness of 200 nm was formed without breaking the vacuum to obtain an organic EL element, which was arranged in a matrix to obtain a display.

(Evaluation results)
First, the luminous efficiencies of the elements used in the examples and comparative examples were 5 to 7 cd / A, and it was found that all of them had high performance. Next, for each display of each example and comparative example, only the selected subpixel was driven with a pulse voltage (duty ratio 1/100, voltage 10 V, fundamental frequency 60 Hz), and a light emission test was performed. As a result, in Examples 1 to 3 of the produced displays, only the desired subpixel was lit, but for the comparative example, lighting of the subpixel adjacent to the desired subpixel was also observed, The occurrence of leakage current was found.

  The production method of the present invention is promising in that an organic EL element that can be applied to various screen display devices that require high visibility can be obtained.

It is sectional drawing along the longitudinal direction of the cathode which shows the manufacturing method of the organic EL element of the passive matrix drive of this invention, (a) is the 1st process until an inorganic insulating film is formed, (b) is an inorganic insulating film. (C) shows the 3rd process of forming a cathode, respectively. It is sectional drawing along the longitudinal direction of the anode which shows the manufacturing method of the organic EL element of the passive matrix drive of this invention, (a) is the 1st process until an inorganic insulating film is formed, (b) is an inorganic insulating film (C) shows the 3rd process of forming a cathode, respectively. It is a schematic diagram which shows the structure of the organic EL element currently disclosed by patent document 3, Comprising: (a) is sectional drawing along the longitudinal direction of a cathode through a light emission part center, (b) is a light emission part center. It is sectional drawing along the longitudinal direction of an anode as follows. It is a schematic diagram which shows the structure of the organic EL element currently disclosed by patent documents 4, 5, Comprising: (a) is sectional drawing which followed the longitudinal direction of the cathode through the center of a light emission part, (b) is light emission. It is sectional drawing which passed along the center of a part and followed the longitudinal direction of the anode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Board | substrate 12 Anode 13 Interlayer insulation film 14 Hole transport layer 15 Organic light emitting layer 16 Electron transport layer 17 Metal thin film 18 Inorganic insulation film 19 Cathode

Claims (4)

A method for manufacturing a passive matrix driving organic EL element,
A plurality of electrode layers are arranged on an insulating substrate in a state of being separated from each other to form an anode row, and at least a hole transport layer, an organic light emitting layer, an electron transport layer, and a metal thin film are formed on the anode row. Forming an organic EL layer, and further forming an inorganic insulating film so as to cover the island-shaped organic EL layer from above;
Etching the inorganic insulating film to expose the metal thin film;
A step of forming a cathode row by disposing a plurality of electrode layers on the metal thin film and the inorganic insulating film and in a state of being separated from each other and orthogonal to the anode row, Manufacturing method of organic EL element.   The method for manufacturing an organic EL element according to claim 1, wherein the etching process is a dry etching process.   2. The method of manufacturing an organic EL element according to claim 1, wherein the etching process is a photoetching process.   2. The method of manufacturing an organic EL element according to claim 1, wherein the etching process is a laser etching process.

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