JP2001313182A - Organic el display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL display device enabled to reduce the number of scanning lines against the number of display lines, to prolong the life of the organic EL element, to improve the brightness, and to reduce the voltage and current of a drive circuit. SOLUTION: The number of scanning lines can be reduced to half by forming data lines in a interdigital shape. As the number of scanning lines can be reduced to half the number of display lines, illuminating period of respective scanning lines can be extended double. Further, when brightness is kept as before, as the current supplied to respective elements can be reduced, power consumption and volume of heat radiation are reduced, and the life of elements is prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an organic EL (electroluminescence) display device. More specifically, the present invention relates to a dot matrix type organic
The present invention relates to an organic EL display device that can reduce the number of scan lines relative to the number of display rows, extend the life of an organic EL element, and achieve high luminance.

[0002]

2. Description of the Related Art In a dot matrix type organic EL display device which performs matrix driving, scan lines are sequentially driven to emit light one row at a time, so that the emission time of a specific scan line is equal to the number of scan lines out of the whole. Never exceed 1. Therefore, as the number of scan lines increases, the emission time of each scan line decreases, and the relative luminance decreases. To compensate for this decrease in luminance, an organic EL
Although a higher luminance is obtained by increasing the current flowing through the element, a higher voltage and a larger current are required for the drive circuit, and the life of the element is shortened.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. By increasing the number of display lines per scan line, the life of the organic EL display device can be improved, the luminance can be increased, and the driving can be improved. An object of the present invention is to provide an organic EL display device capable of reducing the voltage and current of a circuit.

[0004]

An organic EL display device according to the first aspect of the present invention is a dot matrix type organic EL display device driven in a matrix with an anode as a data line and a cathode as a scan line. The display device includes the anode in which a pair of comb-shaped thin films are meshed on a substrate and arranged in a strip shape, and the organic EL film and the cathode arranged in a stripe shape so as to be orthogonal to the anode. Each of the comb-teeth portions, which are sequentially laminated and form a pair with the anode, are arranged so as to divide the short direction of each of the organic EL films and each of the cathodes into two. Further, as shown in the second invention, an auxiliary electrode can be formed on the spine of each anode.

The organic EL display device according to the third aspect of the present invention is a dot matrix type organic EL display device driven in a matrix using an anode as a scan line and a cathode as a data line. An organic EL in which a strip-shaped anode and a pair of comb-shaped thin films are meshed with each other to form a strip and are arranged in a stripe shape so as to be orthogonal to the anode, and each is separated by a partition wall A film and a cathode are sequentially laminated, and each comb-teeth portion forming a pair of the organic EL film and the cathode is arranged so as to divide the short direction of each anode into two.

The "substrate" may be any material that can form an organic EL film, and can be arbitrarily selected. Also, there is no particular limitation on whether the material is transparent. The “organic EL film” is a film that emits light by recombining holes and electrons supplied from the anode and the cathode. The organic EL film includes a light emitting layer including at least an organic fluorescent substance. In addition, at least one of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer can be provided in addition to the light emitting layer. Further, as a material constituting each layer, various materials generally used can be used.

The "anode" and the "cathode" can be formed of various materials.
The present organic EL element can be provided with a sealing member. The sealing member has a joining surface that is joined to the substrate at the periphery thereof, and the other portions are in such a degree that the sealing member does not contact the organic EL laminate including the anode, the organic EL film, and the cathode. It is preferable that the cap has a shape in which a space is formed.

The above-mentioned "comb shape" means a band-like "spine portion".
And “comb portions” provided at equal intervals on one side of the spine portion. Further, the shape of the comb tooth portion can be any shape such as a square shape or a rectangular shape. The “auxiliary resistance” can be formed by any conductive thin film. In particular, a thin film made of a metal such as Cr or Al can be suitably used because of its low resistance.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an organic EL display device according to the present invention will be described with reference to FIGS. In each drawing, the position of each pixel is represented by “row” and “digit”. Also, "scan line" and "row direction"
Is the y direction, and is represented as the first, second, third,...
The "data line" and the "digit direction" are in the x direction, and are expressed as 1, 2, 3,...

[Embodiment 1] The organic EL display device of Embodiment 1 employs a matrix drive in which the number of rows is twice the number of scan lines by making the shape of the anode, which is a data line, comb-shaped. Is a dot matrix type organic EL display device. Organic EL element 1 used in the present organic EL display device
Is a transparent glass substrate 2 as shown in FIGS.
And an anode 31, a partition 4, an organic EL film 32, and a cathode 33, which are sequentially formed on the substrate 2.

The anode 31 is made of an ITO thin film. Organic EL
The film 32 is a thin film formed of an organic fluorescent material or the like and sequentially laminated with a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. The cathode 33 is
It is made of an Al thin film. Further, the organic EL film 32 and the cathode 33
Are formed in a stripe shape by being separated by the partition walls 4.

An anode 31 as a data line is shown in FIG.
As shown in FIG. 3, a pair of comb-shaped electrodes u and d are combined so as to form a substantially strip shape, and are arranged side by side so as to form a stripe shape. Of these, the electrodes u1, u2,
The comb teeth of u3 and the comb teeth of the electrodes d1, d2, d3... alternately mesh with each other.

Further, the comb teeth of the electrodes u1, u2, u3... (The bold rectangular parts illustrated in FIG. 3) are located above the respective cathodes 33, which are scan lines, and the comb teeth d1, d1 of the electrode d. .. are located below each cathode 33. Therefore, a certain cathode 33
(Tentatively, s2) and a certain anode 31 (tentatively, an anode 31, x = 2, u2, d2) intersect in a region where the anode 31
u2 and d2 are located at the top and bottom, respectively, the second digit and the third row
And the fourth pixel. That is,
In order to make the pixel of (row, column) = (2, 3) emit light, a current may be passed between the cathode 33 of s2 and the anode of u2. Also,
In order to make the pixel of (row, column) = (2, 4) emit light, a current may be passed between the cathode 33 of s2 and the anode of d2. Note that the spine portion of the anode 31 does not emit light because the insulating layer 5 is formed thereon as shown in FIG.

An organic EL having such an organic EL element
The display device can reduce the number of scan lines to half the number of display lines. Further, since the number of scan lines can be reduced to half of the number of display lines, the emission time of each scan line can be doubled. by this,
When the same amount of current is applied to each element, the light emission luminance that can be sensed by humans can be increased.

Further, as shown in FIG. 5B, the rising of the waveform of the pulse current for driving the organic EL element is slowed down, so that the luminance is reduced accordingly. This dulling occurs for the following reasons. That is, a reverse bias voltage is applied to each non-lighted pixel of the organic EL element to prevent crosstalk, and the pixels are charged with reverse charges. In order to light this pixel, an electric charge for eliminating the charged reverse electric charge is required, and the rising becomes slower by this electric charge.

However, the present organic EL display device has the structure shown in FIG.
As shown in FIG. 5A, one pulse can be set to a time twice as long as the conventional driving time.
(See the hatched portions in (a) and (b)) can be reduced to less than two conventional pulses. For this reason, the organic EL display device can also reduce a decrease in luminance due to the dulling.

Further, when the light emission luminance is the same level as the conventional one, the amount of current flowing through each element can be reduced. For this reason, power consumption is reduced, the amount of generated heat is reduced, and the life of the element can be prolonged.

When the drive time of each scan line is the same as that of the conventional case, the number of display rows can be doubled.

[Embodiment 2] In the organic EL display device of Embodiment 2, similarly to the organic EL display device of Embodiment 1, the number of scan lines is reduced by making the shape of the anode, which is the data line, comb-shaped. This is a matrix-driven dot-matrix organic EL display device that performs display with twice the number of rows.

The organic EL device used in the organic EL display device of the first embodiment has a high resistance because the backbone of the anode 31 is narrow, and the luminance is sometimes reduced because the current is limited. Therefore, in the second embodiment, an auxiliary electrode is provided to reduce the resistance of this portion. As shown in FIGS. 6 and 7, the organic EL element used in the organic EL display device according to the second embodiment has an auxiliary electrode 311 formed on the spine of the anode 31 of the organic EL element according to the first embodiment. The auxiliary electrode 311 is a thin film on which a metal such as Cr or Al is deposited.

By providing such an auxiliary electrode 311, the spine of the anode 311 can have a low resistance,
It is possible to prevent the emission luminance from being reduced. Further, since the formation portion of the auxiliary electrode 311 is not a light emitting portion, there is no hindrance to light emission.

[Embodiment 3] The organic EL display device of Embodiment 3 employs a matrix drive for performing display with twice the number of scan lines by making the shape of the cathode as a data line comb-shaped. Is a dot matrix type organic EL display device. Organic EL element 1 used in the present organic EL display device
As shown in FIG. 8 to FIG. 11, a transparent glass substrate 2 is provided, and an anode 31, a partition 4, an organic EL film 32, and a cathode 33 are sequentially formed on the substrate 2.

The anode 31 has an IT formed in a stripe shape.
It consists of an O thin film. The organic EL film 32 is a thin film composed of an organic fluorescent material and the like, in which layers such as a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are sequentially laminated. The cathode 33 is made of an Al thin film. Further, the organic EL film 32 and the cathode 33 are separated by the partition 4.

The cathode 33, which is a data line, is shown in FIG.
As shown in FIG. 10, a pair of comb-shaped electrodes u and d are combined so as to form a substantially strip shape, and are arranged side by side so as to form a stripe shape. Of these, electrodes u1, u
, And the comb teeth of the electrodes d1, d2, d3,... Alternately mesh with each other.

Further, the comb-tooth portions (thick-line rectangular portions shown in FIG. 10) of the electrodes u1, u2, u3,... Are located above the respective anodes 31 which are scan lines, and the comb-tooth portions d1, d2 of the electrode d. , d3 ... are located below each anode 31. For this reason, a certain anode 31 (probably s2) and a certain cathode 33 (probably a cathode 3 of x = 2)
3, u2, and d2) intersect with each other.
And d2 are located at the top and bottom, respectively, and can be used as the second pixel and the third and fourth pixels, respectively. That is,
In order to cause the pixel of (row, column) = (2, 3) to emit light, a current may be passed between the anode 31 of s2 and the cathode of u2. Also,
In order to cause the pixel of (row, column) = (2, 4) to emit light, a current may be passed between the anode 31 of s2 and the cathode of d2. As shown in FIG. 11A, the spine portion of the cathode 33 does not emit light because the insulating layer 5 is formed below the spine portion.

An organic EL having such an organic EL element
The display device can halve the number of scan lines with respect to the number of display lines as in the first and second embodiments. Further, since the number of scan lines can be reduced to half of the number of display lines, the emission time of each scan line can be doubled. As a result, when the same amount of current is applied to each element, it is possible to increase the light emission luminance that can be sensed by humans. Further, by setting the light emission luminance to the same level as that of the related art, the amount of current flowing to each element can be reduced. For this reason, power consumption is reduced, the amount of generated heat is reduced, and the life of the element can be prolonged. Further, when the drive time of each scan line is the same as in the conventional case, the number of display rows can be doubled.

The present invention is not limited to the above embodiment, but may be variously modified within the scope of the present invention according to the purpose and application. That is, among the comb-teeth shapes of the respective embodiments, the shape of the comb-teeth portion is rectangular, but may be square. Further, the anode 3 of Examples 1 and 2
Although the electrodes u and d of the cathode 33 of Example 1 and Example 3 are provided at the upper and lower ends of the substrate, respectively, only one of the ends can be provided.

[0028]

According to the organic EL display device of the present invention,
The number of scan lines can be reduced with respect to the number of display rows, the life of the organic EL element can be extended, and high luminance can be achieved. In addition, lower voltage and lower current of the driver circuit can be achieved.

[Brief description of the drawings]

FIG. 1 illustrates an organic EL used in an organic EL display device according to a first embodiment.
FIG. 3 is a plan view for describing a configuration of an L element.

FIG. 2 is a schematic plan view for explaining a pattern shape of an anode according to the first embodiment.

FIG. 3 is a partially enlarged view for explaining in detail a pattern shape of an anode according to the first embodiment.

FIG. 4 illustrates an organic EL used in the organic EL display device according to the first embodiment.
FIG. 3 is a schematic cross-sectional view in an X direction (a) and a Y direction (b) for explaining a configuration of an L element.

FIGS. 5A and 5B are driving waveforms of the organic EL element of the present embodiment and FIG.

FIG. 6 is a schematic plan view for explaining a pattern shape of an anode according to a second embodiment.

FIG. 7 illustrates an organic EL used in the organic EL display device according to the second embodiment.
FIG. 3 is a schematic cross-sectional view in an X direction (a) and a Y direction (b) for explaining a configuration of an L element.

FIG. 8 illustrates an organic EL used in the organic EL display device according to the third embodiment.
FIG. 3 is a plan view for describing a configuration of an L element.

FIG. 9 is a schematic plan view for explaining a pattern shape of an anode according to a third embodiment.

FIG. 10 is a partially enlarged view for explaining in detail a pattern shape of an anode according to a third embodiment.

FIG. 11 is a schematic cross-sectional view in the X direction (a) and the Y direction (b) for explaining the configuration of the organic EL element used in the organic EL display device of the third embodiment.

[Explanation of symbols]

1; organic EL element, 2; substrate, 31; anode, 311; auxiliary electrode, 32; organic EL thin film, 33; cathode, 4;
5; insulating layer.

Claims (3)

[Claims] 1. A dot matrix type organic EL display device driven in a matrix with an anode as a data line and a cathode as a scan line, wherein the organic EL display device has a pair of comb-shaped thin films meshed on a substrate. The above-mentioned anode, in which the strips are arranged in a strip shape, and the organic EL films and the above-mentioned cathodes, which are arranged in a stripe shape so as to be orthogonal to the anode, are sequentially laminated, and each of the comb teeth portions forming a pair of the anodes Is disposed so as to divide the short direction of each of the organic EL films and each of the cathodes into two. 2. The organic EL display device according to claim 1, wherein an auxiliary electrode is formed on a backbone of each anode. 3. A dot matrix type organic EL display device driven in a matrix with an anode as a scan line and a cathode as a data line, the organic EL display device comprising: an anode arranged in a stripe on a substrate; A band-shaped one in which a pair of comb-shaped thin films are engaged is arranged in a stripe shape so as to be orthogonal to the anode, and an organic EL film and a cathode each separated by a partition are sequentially laminated, An organic EL display device, wherein the comb-teeth portions forming a pair of the organic EL film and the cathode are arranged so as to divide the short direction of each anode into two.