JP2004279723A - Display circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent thinning of electrodes and narrowing of a pitch in a connecting part, and to increase the number of electrodes without enlarging an area of the connecting part. <P>SOLUTION: A display circuit comprises on a substrate 1 a 1st group of electrodes 2, 3 parallel to each other, a 2nd group of electrodes 4 parallel to each other crossing the 1st group of electrodes 2, 3, and a display part which is located at the intersectional positions of the 1st group of electrodes 2, 3 and the 2nd group of electrodes 4 and includes light emitting elements 5 connected to each electrode. This display circuit is further provided with a 1st connecting part 11 arranged in the periphery of the substrate 1 and a 2nd connecting part 12 arranged between the 1st connecting part 11 and display part to connect the electrodes extended to the periphery of the substrate 1 from the display part to another substrate, and as to the 1st group of electrodes 2, 3, adjacent electrodes are alternately extended to the 1st connecting part 11 and the 2nd connecting part 12, respectively, and the electrodes 3 extended to the 2nd connecting part are laminated on the electrodes 2 extended to the 1st connecting part via an insulating film 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display circuit, and more particularly, to a display circuit having a connection portion for connecting a driving portion and a display portion in a passive matrix display.
[0002]
[Prior art]
In recent years, as a flat panel display replacing a liquid crystal display, an organic EL display using an organic EL (Electro Luminescence) element in a pixel portion has attracted attention. The organic EL display is a self-luminous element, has high visibility and can be driven at a low voltage, and has been actively studied for practical use. The organic EL element has an organic layer containing an organic compound that emits light when an electric field is applied, and an anode and a cathode sandwiching the organic layer. Some organic compounds utilize fluorescence due to singlet excitation and phosphorescence due to triplet excitation.
[0003]
As a driving method for driving each pixel portion of the organic EL display, a passive matrix type and an active matrix type are known as in the liquid crystal display. The passive matrix type has advantages such as low cost and high yield because of its simple structure.
[0004]
The passive matrix type display includes a plurality of anodes on a transparent substrate, a plurality of cathodes intersecting the anodes, and an organic layer sandwiched between the anodes and the cathodes. One pixel portion is formed with the light emitting element in the intersection region of the anode and the cathode as one unit, and a plurality of the pixel portions are arranged to form a display portion. The anode and the cathode are extended from the display section to the periphery of the transparent substrate to form a connection section. A display circuit is configured by connecting the drive unit and the display unit via the connection unit. A display device is configured by connecting a display circuit and a control circuit that converts an image signal input from the outside and controls a driving unit.
[0005]
In order to produce a display with high definition and a high pixel count, it is necessary to increase the number of anode and cathode electrodes. If the display units have the same display area, the pitch between the electrodes is also reduced, and the pitch between the electrodes in the connection unit is also reduced. Further, as the definition becomes higher, the scanning time allocated to one scanning electrode becomes shorter, and the current flowing through the pixel portion must be increased in order to obtain the required luminance. In view of this, it has been practiced to divide the display section into upper and lower parts and increase the number of electrodes that are simultaneously scanned to increase the scanning time (for example, see Patent Documents 1 and 2). In this case, the number of electrodes at the connection portion further increases according to the number of divisions.
[0006]
[Patent Document 1]
Japanese Patent Publication No. 1-57350
[Patent Document 2]
JP 2000-56707 A
[Problems to be solved by the invention]
When the number of electrodes in the connection portion increases, there has been a problem that high-precision alignment between the substrate having the drive portion and the transparent substrate having the connection portion is required, and the yield is reduced.
[0009]
In addition, there is a problem that the area of the connecting portion formed to extend around the transparent substrate increases in order to secure a predetermined electrode width and a predetermined pitch.
[0010]
The present invention has been made in view of such a problem, and an object of the present invention is to provide a display circuit capable of increasing the number of electrodes without increasing the area of a connection portion. .
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an image forming apparatus according to claim 1, wherein m first sets of electrodes parallel to each other are provided on a substrate, and the first set of electrodes intersects the first set of electrodes. N second sets of electrodes arranged in parallel with each other (m and n are integers) are arranged at each of intersections between the first set of electrodes and the second set of electrodes, and In a display circuit having a display unit including a light-emitting element connected thereto, a first circuit provided around the substrate to connect an electrode extended from the display unit to the periphery of the substrate and another substrate. And a second connection portion provided between the first connection portion and the display portion, wherein the first set of electrodes and / or the second set of electrodes are adjacent to each other. Electrodes are respectively alternately extended to the first connection part and the second connection part, and the electrodes extended to the second connection part are respectively provided. It is characterized by being stacked through an insulating film on the extended electrodes on the first connection portion.
[0012]
According to this configuration, by connecting every other electrode to a different substrate, thinning and narrowing of the electrodes can be prevented, and short-circuiting can be prevented by covering the electrodes with an insulating film.
[0013]
According to a second aspect of the present invention, the first set of electrodes and / or the second set of electrodes according to the first aspect are made of a transparent conductive film material of either ITO or an In-Zn oxide film. It is characterized.
[0014]
According to a third aspect of the present invention, in the first connection part and the second connection part according to the first aspect, the first set of electrodes and / or the second set of electrodes include Mo, Cr, It is characterized by being made of one of Ni and W metals.
[0015]
The invention according to claim 4 is characterized in that the insulating film according to claim 1, 2 or 3 is formed of an inorganic oxide film.
[0016]
The invention according to claim 5 is characterized in that the other substrate according to any one of claims 1 to 4 is a flexible printed circuit board.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In one embodiment of the present invention, in the connection portion, by forming the electrode into a multilayer structure with an insulating layer interposed therebetween, it is possible to prevent thinning and narrowing of the electrode, to simplify the alignment, and to reduce the area of the connection portion. To prevent it from expanding.
[0018]
In the following description, a passive matrix display using an organic EL element will be described, but only the first electrode corresponding to either the anode or the cathode will be described, and other detailed configurations of the display will be omitted. A color filter layer, a color conversion layer, a polymer layer, an inorganic layer, or the like formed on a transparent substrate is integrally referred to as a first electrode substrate.
[0019]
FIG. 1 shows a display unit and a connection unit of a passive matrix display according to a first embodiment of the present invention. On the first electrode substrate 1, a plurality of first electrodes 2, 3, a plurality of second electrodes 4 intersecting the first electrodes 2, 3, and sandwiched between the first electrodes 2, 3 and the second electrode 4. And an organic light emitting layer 5. The intersection area of the organic light emitting layer 5 sandwiched between the first electrodes 2 and 3 and the second electrode 4 constitutes one pixel portion. The first electrodes 2, 3 can function as anodes or cathodes, and the second electrodes 4 can also function correspondingly as cathodes or anodes.
[0020]
When the light from the organic light emitting layer 5 is extracted from the first electrode substrate 1 side, a transparent conductive film is used for the first electrodes 2 and 3. As the transparent conductive film material, ITO (Indium Tin Oxide), an In-Zn oxide film, ATO, or the like can be used. In particular, an In—Zn oxide film that can obtain a film having a relatively low resistance by film formation at room temperature and can be patterned by a weak acid is preferable. As a film forming method, patterning is performed by photolithography using a sputtering method or the like.
[0021]
The first electrodes 2 and 3 may be formed of a transparent conductive film for both the display section and the connection section. A connection part that does not need to transmit light may be connected to a transparent conductive film using a lower resistance metal as an auxiliary electrode. As the auxiliary electrode material, Al, Mo, Cr, Ni, W, Al alloy and alloys thereof can be used. The auxiliary electrode is patterned by photolithography using a sputtering method or the like. Further, it may be formed by lift-off, mask film formation, or the like.
[0022]
Although the organic light emitting layer 5 is illustrated as a single layer, it can be formed by combining an electron injection layer, a hole injection layer, a hole transport layer, and the like. Known materials are used for forming each layer. For example, the organic light-emitting layer 5 that emits blue to blue-green light is formed of a benzothiazole-based, benzimidazole-based, benzoxazole-based fluorescent whitening agent, a metal-chelated oxonium compound, a styrylbenzene-based compound, an aromatic dimethylidin-based compound, or the like. Use
[0023]
For the second electrode 4, Al, Mg, or an alloy thereof can be used. The second electrode 4 can be formed by a sputtering method using a mask. Although not shown, an inorganic film such as silicon oxide or silicon oxynitride can be formed after the second electrode 4 is formed, thereby forming a sealing member. Further, the display portion or the display can be sealed using a glass substrate, a SUS can, a film substrate such as a polycarbonate, and a UV curable resin.
[0024]
FIG. 2 shows a connection section according to the first embodiment of the present invention. FIG. 2 is a sectional view taken along a broken line AA ′ shown in FIG. 1. On the first electrode substrate 1, a plurality of lower first electrodes 2a to 2d, an insulating film 6, and upper first electrodes 3a to 3d are sequentially stacked. The lower first electrodes 2a to 2d extend from the display unit to the first connection unit 11 around the first electrode substrate 1, and are connected to the driving unit via a flexible printed board at the electrode ends. The lower first electrodes 2 a to 2 d in the second connection portion 12 are covered with the insulating film 6. The upper first electrodes 3a to 3d are extended to the second connection part 12 on the insulating film 6, and are connected to the driving part via a flexible printed board at the electrode end.
[0025]
The insulating film 6 can be made of an inorganic oxide, a negative photoresist such as acrylate, or a polyimide material. After the inorganic oxide is formed by a sputtering method or the like, patterning is performed by photolithography. Further, it may be formed by lift-off, mask film formation, or the like.
[0026]
With such a configuration, a display circuit is configured by connecting the drive unit and the display unit via the connection units 11 and 12. Further, details of the connection units 11 and 12 will be described.
[0027]
FIG. 3 shows the connection between the first electrode and the flexible printed circuit board. A conductive portion 8a corresponding to the lower first electrodes 2a to 2d is formed on the flexible printed circuit board 7a, and the conductive portion 8a and the lower first electrodes 2a to 2d are heated using an anisotropic conductive adhesive film. Crimp. A conductive portion 8b corresponding to the upper first electrodes 3a to 3d is formed on the flexible printed board 7b, and the conductive portion 8b and the upper first electrodes 3a to 3d are heated using an anisotropic conductive adhesive film. Crimp.
[0028]
In the connection portion, adjacent electrodes are arranged in a multilayer structure with an insulating layer interposed therebetween, and every other electrode is connected to a different flexible printed circuit board 7a, 7b. In this way, each of the first connection part 11 and the second connection part 12 is connected to the drive part via the flexible printed circuit boards 7a and 7b.
[0029]
FIG. 4 is a top view showing a display unit and a connection unit of a passive matrix display according to a second embodiment of the present invention. On the first electrode substrate 1, a plurality of lower first electrodes 2a to 2c, an insulating film 6, and upper first electrodes 3a to 3c are sequentially stacked. In the second embodiment, the display portion formed by the organic light emitting layer is divided into upper and lower portions, and an upper display portion 21 and a lower display portion 22 are formed. The illustration of the second electrode is omitted.
[0030]
The lower first electrodes 2a to 2c extend from the lower display unit 22 to the first connection unit 11 around the first electrode substrate 1, and are connected to the drive unit via the flexible printed circuit board at the electrode ends. The lower first electrodes 2 a to 2 d in the second connection portion 12 are covered with the insulating film 6. The upper first electrodes 3a to 3d extend from the upper display unit 21 to the second connection unit 12 on the insulating film 6, and are connected to the drive unit via a flexible printed board at the electrode ends. The connection between the first electrodes 2 and 3 and the organic light emitting layer 5 is performed by the transparent conductive films 9 and 10.
[0031]
After a color conversion filter made of a dye or a pigment was formed on a transparent substrate, a polymer film layer and an inorganic film layer were formed to obtain a first electrode substrate 1. As a polymer film layer, a UV curable resin was applied by a spin coating method, and irradiated with a high-pressure mercury lamp to form a film having a thickness of 8 μm. The upper surface of the polymer film layer is flat. As the inorganic film layer, a 300 nm-thick SiOx film was formed at room temperature by an RF sputtering method. Si was used as a sputtering target, and a mixed gas of Ar and oxygen was used as a sputtering gas.
[0032]
As the lower first electrodes 2a to 2c, 300 nm of Mo was formed at room temperature by DC sputtering. A Mo target was used as a sputtering target, and Ar was used as a sputtering gas. Then, after patterning the resist by a photolithographic method, an electrode pattern having a width of 7 μm and a spacing of 58 μm was formed by patterning using a mixed solution of phosphoric acid, nitric acid and acetic acid as an etching solution.
[0033]
As the insulating film 6, an SiOx film was formed to a thickness of 300 nm at room temperature by an RF sputtering method, and was patterned by a lift-off method.
[0034]
As the first electrodes 3a to 3c, Mo was deposited to a thickness of 300 nm at room temperature by DC sputtering. The sputtering method conditions and patterning are the same as those for the lower first electrodes 2a to 2c. The upper first electrodes 3a to 3c had a width of 7 μm and an interval of 58 μm, and had a pattern 3 mm shorter than the lower first electrodes 2a to 2c when viewed from the display unit.
[0035]
The transparent conductive films 9 and 10 were formed using an In-Zn oxide film by a DC sputtering method at a room temperature of 220 nm. An In—Zn oxide firing target was used as a sputtering target, and a mixed gas of Ar and oxygen was used as a sputtering gas. After patterning the resist by photolithography, patterning was performed using oxalic acid as an etchant.
[0036]
The first electrode substrate 1 on which the first electrodes 2 and 3 are formed is mounted in a resistance heating evaporation apparatus, and an organic light emitting layer including a hole injection layer, a hole transport layer, an organic light emitting layer, and an electron injection layer is formed. 5 was formed. The hole injection layer is formed by laminating copper phthalocyanine (CuPc) to a thickness of 100 nm, and the hole transport layer is formed by depositing 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD) to a thickness of 20 nm. Laminated. The organic light emitting layer was formed by laminating 30 nm of 4,4′-bis (2,2′-diphenylvinyl) biphenyl (DPVBi), and the electron injection layer was formed by laminating 20 nm of aluminum chelate (Alq).
[0037]
As the second electrode 4, Mg / Ag (weight ratio 10: 1) was formed to a thickness of 200 nm using a mask having a stripe pattern with a width of 110 μm and a gap of 20 μm. Finally, sealing was performed using a sealing glass and a UV-curable adhesive in a dry nitrogen atmosphere (both oxygen and moisture concentrations are 10 ppm or less) in the glove box.
[0038]
The flexible printed circuit board 6 was heat-pressed to the display unit thus manufactured using an anisotropic conductive adhesive film, and a driving unit was connected to form a display circuit. When a display device was configured by connecting a control circuit for controlling the drive unit and a display circuit, and the display device was driven, it was possible to drive satisfactorily without a short circuit.
[0039]
In the present embodiment, a passive matrix display using an organic EL element has been described, but the light emitting element is not limited to the organic EL element. Further, the connection portions 11 and 12 of the first electrodes 2 and 3 have been described, but the present embodiment can be applied to the second electrode 4.
[0040]
【The invention's effect】
As described above, according to the present invention, the adjacent electrodes are alternately extended to the first connection part and the second connection part, respectively, and the electrode extended to the second connection part is the first connection part. Since the electrode is laminated on the electrode extended to the connection portion via an insulating film, every other electrode can be connected to a different substrate, and the number of electrodes can be increased without increasing the area of the connection portion. Can be increased.
[Brief description of the drawings]
FIG. 1 is a top view showing a display unit and a connection unit of a passive matrix display according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating a connection portion according to the first embodiment of the present invention.
FIG. 3 is a diagram showing a connection between a first electrode and a flexible printed circuit board.
FIG. 4 is a top view showing a display unit and a connection unit of a passive matrix display according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st electrode substrate 2 lower 1st electrode 3 upper 1st electrode 4 2nd electrode 5 organic light emitting layer 6 insulating film 7 flexible printed circuit board 8 conductive part 9, 10 transparent conductive film 11 first connection part 12 second connection part 21 Upper display unit 22 Lower display unit

Claims (5)

A first set of m parallel electrodes on a substrate, and a second set of n parallel electrodes arranged intersecting the first set of electrodes (m and n are integers); A display circuit, comprising: a display unit that is disposed at each of intersections of the first set of electrodes and the second set of electrodes and includes a light emitting element connected to each of the electrodes.
A first connection unit provided around the substrate to connect an electrode extended from the display unit to the periphery of the substrate and another substrate;
A second connection unit provided between the first connection unit and the display unit;
In the first set of electrodes and / or the second set of electrodes, adjacent electrodes are alternately extended to the first connection part and the second connection part, respectively, and are extended to the second connection part. A display circuit, wherein the provided electrode is laminated via an insulating film on the electrode extended to the first connection portion. 2. The display circuit according to claim 1, wherein the first set of electrodes and / or the second set of electrodes are made of a transparent conductive film material of one of ITO and an In—Zn oxide film. 3. The first set of electrodes and / or the second set of electrodes in the first connection portion and the second connection portion are made of any one of Mo, Cr, Ni, and W. The display circuit according to claim 1. The display circuit according to claim 1, wherein the insulating film is formed of an inorganic oxide film. The display circuit according to claim 1, wherein the other substrate is a flexible printed circuit board.

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