JP2000029432A - Organic el display device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To increase the signal width of each scanning line (reduce the drive duty ratio), reduce the instantaneous luminance, and reduce the electrical and thermal damage of the element. , The element's initial performance can be maintained for a long period of time, and even if it has a large screen or a high-definition display screen, the necessary light emission luminance can be secured, so that a high-quality, high-definition display can be obtained. Further, an organic EL display device capable of further increasing the emission luminance and obtaining a higher definition display screen is realized. An organic EL display device having individual organic EL elements defined as a combination of row and column elements, wherein at least one of the rows and columns is driven by two or more drive systems. An EL display device was used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an organic EL display device having a plurality of organic EL elements connected in a matrix.

[0002]

2. Description of the Related Art In recent years, organic EL devices have been actively studied,
It is being put to practical use. In this method, a hole transport material such as triphenyldiamine (TPD) is formed into a thin film on a transparent electrode (hole injection electrode) such as tin-doped indium oxide (ITO) by vapor deposition, and then an aluminum quinolinol complex (A
1q3) as a light emitting layer, and a metal electrode such as Mg having a small work function (electron injection electrode)
It is an element with a basic structure that has formed a very high brightness of several hundreds to several tens of thousands cd / m ² at a voltage of about 10 V, which has attracted attention as a display for electrical components such as home appliances, automobiles, motorcycles, and aircraft. I have.

In such an organic EL device, for example, an organic layer such as a light emitting layer has a scanning (common line) electrode serving as an electron injection electrode and a data (segment line) electrode serving as a hole injection electrode (transparent electrode). And a structure formed on a transparent (glass) substrate. In the case of a display formed as a display, a matrix display that displays dots and information as an aggregate of these dots (pixels) using scanning electrodes and data electrodes arranged in a matrix form. When,
It is roughly classified into a segment display for displaying an independently existing display having a predetermined shape and size.

In the case of a segment type display,
A static drive system in which each display is displayed separately and independently is also possible, but in the case of a matrix display, a dynamic drive system in which each scan line and data line are time-divisionally driven is usually adopted.

[0005] Organic EL display devices, such as a dot matrix type, have been put into practical use as display devices with a constant luminance, and attempts to adjust the light emission gradation have been made, but are not sufficient. For this reason, in order to realize a high-quality display screen, it is necessary to further adjust the emission gradation with high accuracy.

[0006] Since the luminance of the organic EL element can be controlled by the supplied power, for example, Japanese Patent Application Laid-Open No. 5-30351 is disclosed.
As disclosed in Japanese Unexamined Patent Publication (Kokai) No. H11-260, there has been proposed a device in which a gradation signal is a voltage signal applied to an element. Also, JP-A-6-3
As can be seen from JP-A-01355, attempts have been made to introduce so-called PWM control, which controls the power supply time while keeping the instantaneous power constant.

However, when an attempt is made to increase the display area or realize a high-definition display, the number of pixels increases.
It takes more time to scan this, or shorten the signal time per pixel. However, when the signal time is shortened, the instantaneous luminance per pixel for obtaining the required luminance must be increased, so that the electric stress per pixel and the stress due to heat generation increase, thereby deteriorating the element and shortening the lifetime. In some cases, eventually destroying the device. If the signal time is too long, the screen flickers, and eventually the display quality cannot be maintained or it becomes difficult to recognize the displayed image.

Further, a desired luminance may not be obtained or a luminance required for maintaining display quality may not be obtained.
Further, the brightness gradation is limited by the ratio of the minimum pulse width to the maximum pulse width. For this reason, in the display of a moving image, in the case where the simplest pixels are sequentially scanned one by one, even a normal television image can take a signal time of only about 0.25 μs per pixel. Therefore, it is difficult to drive with the signal obtained by further dividing this time, and the light emission speed cannot catch up with it in the first place.

Even when scanning one line at a time, in the case of a television signal, the signal time is about 64 μs, and
In the case of the L element, when the minimum response time is considered to be about 10 μs, it is understood that it is difficult to secure the light emission luminance on the entire display surface. Further, the ratio of the minimum pulse width to the maximum pulse width is only about 6, and it is understood that it is difficult to increase the number of gradations in consideration of the contrast ratio.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to secure a necessary light emission luminance even when a large screen or a high-definition display screen is provided, so that a high-quality and high-definition display can be obtained. Further, it is an object of the present invention to provide an organic EL display device capable of suppressing the instantaneous luminance to a low level, reducing electrical and thermal damage to the element, and maintaining the initial performance of the element for a long period of time.

Another object of the present invention is to realize an organic EL display device capable of further increasing the emission luminance and obtaining a higher definition display screen.

[0012]

That is, the above object is achieved by the following constitutions. (1) An organic EL display device having individual organic EL elements defined as a combination of row and column elements, wherein at least one of the row and column is driven by two or more drive systems. Display device. (2) The organic EL display device according to (1), wherein the two or more drive systems are driven with a duty smaller than a display resolution in a direction in which the entire screen is scanned. (3) The organic EL display device according to the above (1) or (2), wherein the row or column element driven by the two or more types of driving systems is on the scanning electrode side. (4) In each of the row or column elements, the organic EL elements in one row or column element are divided into systems corresponding to a plurality of electrode wirings, and each of the divided pixels corresponds to each electrode wiring. (1) connected to
The organic EL display device according to any one of (1) to (3). (5) The organic EL display device according to any one of (1) to (4), wherein the number of the electrode wires is greater than the number of the corresponding row or column elements. (6) The organic EL display device according to (5), wherein the number of the electrode wirings is an integral multiple of the number of the corresponding row or column elements. (7) The organic EL display device according to any one of (4) to (6), wherein the organic EL elements in the one row or column element are sequentially and alternately connected to each electrode wiring. (8) The organic EL display device according to (7), wherein two electrode wirings are arranged on both sides of the organic EL element as one pixel. (9) The organic EL display device according to any one of the above (1) to (8), wherein the electrode wiring has a three-dimensionally arranged multilayer structure. (10) The organic EL display device according to any one of (1) to (6) above, wherein the electrode wiring has a multilayer structure in which the wiring is three-dimensionally arranged on one side of an organic EL element as a pixel. (11) The electrode wiring is an organic E which is one pixel.
The organic EL display device according to the above (9), wherein the organic EL display device has a multilayer structure in which two layers are arranged on both sides of the L element and three-dimensionally arranged. (12) The organic EL display device according to any one of the above (1) to (11), which is a simple matrix and / or segment type display. (13) An organic EL display device having individual organic EL elements defined as a combination of row and column elements, wherein at least one of the row and column is driven by two or more types of driving systems, and Alternatively, each organic EL element of a column element is divided into a system corresponding to the electrode wiring, and the divided organic EL element is connected to each corresponding electrode wiring. (14) The organic EL display device according to (13), wherein the row or column element driven by the two or more types of driving systems is on the scanning electrode side. (15) The organic EL display device according to (13) or (14), wherein the two or more drive systems are driven with a duty smaller than a display resolution in a scanning direction of the entire screen. (16) The organic EL display device according to any one of (13) to (15), wherein the number of the electrode wirings is greater than the number of corresponding row or column elements. (17) The organic EL according to (16), wherein the number of the electrode wirings is an integral multiple of the number of the corresponding row or column elements.
Display device. (18) The organic EL display device according to any one of (13) to (17), wherein the organic EL elements in the one row or column element are sequentially and alternately connected to each electrode wiring. (19) The organic EL according to (18), wherein two electrode wirings are arranged on both sides of the organic EL element as one pixel.
Display device. (20) The organic EL display device according to any one of the above (13) to (19), wherein the electrode wiring has a three-dimensionally arranged multilayer structure. (21) The above-mentioned (1) wherein the electrode wiring has a multilayer structure three-dimensionally arranged on one side of an organic EL element which is a pixel.
3) The organic EL display device according to any one of (18) to (18). (22) The electrode wiring is one pixel, the organic E
(20) The organic EL display device according to the above (20), which has a multilayer structure in which two elements are arranged on both sides of the L element and three-dimensionally arranged. (23) The organic EL display device according to any one of (13) to (22), which is a simple matrix and / or segment type display.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An organic EL display device according to the present invention is an organic EL display device having individual organic EL elements defined as a combination of row and column elements, wherein at least one of the rows and columns is provided. , Driven by two or more drive systems. Preferably, the two or more drive systems are driven with a duty smaller than the display resolution in the scanning direction of the entire screen.

As described above, the row or column elements of the simple matrix and / or character display device are divided so as to be driven by two or more drive systems, and preferably each is independently displayed in the scanning direction of the entire screen. By driving with a duty smaller than the resolution, the scan time in each divided drive screen can be secured, or the speed can be further increased, and the signal width per pixel can be increased, and the entire screen can be taken. Luminous brightness can be ensured or further increased.

As a means for dividing the screen, it is preferable that a signal width per scanning line scanned in a time-division manner, that is, a driving time can be as large as possible. By driving the scanning line side by dividing into a plurality of driving systems and driving the data line side by dividing into a plurality of driving systems in accordance with the driving line, it is possible to increase the signal width per scanning line in time division driving. As a result, desired luminance can be obtained with low voltage and low current, electric and thermal stress of the element can be reduced, and overall luminance can be improved.

Next, more specific contents of the present invention will be described with reference to the drawings.

FIG. 1 is a conceptual diagram of a display showing a first configuration example of the present invention. In the illustrated example, one screen is divided into upper and lower screens 11 and 12 on the scanning line (common line) side and driven by respective drive systems. By dividing the scanning line side up and down on the scanning line side, for example, on the display surface of the scanning line 240 × the data line 320, the pixel driven with the signal width of the duty ratio 1/240 is reduced by the duty ratio 1/120. It can be driven, and the driving time per pixel can be doubled. In this case, the scanning lines (common lines) com-1 to com-
n and the scanning line (common line) com-1 of the lower screen 12
~ Com-n are sequentially scanned at the same timing. That is, com-1 of the upper screen 11 and com-1 of the lower screen 12 are driven simultaneously. Further, the data lines (segment lines) seg-1 to seg-n of the upper screen 11 and the lower screen 12 are independently driven and supplied with data. Therefore, functionally, a display of 120 scanning lines × 640 data lines is driven.

When the upper screen 11 and the lower screen 12 are driven, the upper limit screens 11 and 12 are combined and the display data may be developed and driven so as to be displayed as one screen. May be driven separately.

FIG. 2 is a conceptual diagram of a display showing a second configuration example of the present invention. In this example, each pixel 21- of one system line (segment side: for example, seg-1)
1 to 21-n are respectively separated into two systems 21-1, 21-3 and 21-2, 21-n, and the separated systems 21-1, 21-3 and 21-2, 21-n are further separated. The electrode wirings 32 and 31 are prepared for each system 2
Pixels 1-1, 21-3 and 21-2, 21-n are connected to respective electrode wirings 32, 31. Each of the electrode wires 32, 31 is connected to a terminal 32 at the bottom of the screen.
a, 31a. And these strains
It is driven for each system. As a result, each of the segment lines seg-1 to seg-5 is divided into two systems, and the screen is divided into two.

The divided two segment lines are:
Each can be driven (scanned) simultaneously. That is, in the illustrated example, the pixels 21-1 and 21-
2 can be driven simultaneously. As a result, the scanning time can be reduced to half of the conventional one, the driving time per scanning line can be increased, the instantaneous light emission luminance per pixel can be reduced, and the electric and thermal stress of the element can be reduced. Can be reduced. Further, the scanning time can be shortened, so that the screen can be made finer and the emission luminance can be improved. In the illustrated example, one system of pixels is alternately connected to two electrode wirings, but may be divided vertically and connected to each other, or an irregular connection method may be adopted. However, in consideration of the influence of the electric resistance of the electrode wiring, it is preferable to alternately connect the wirings as shown in the illustrated example.

The divided two segment lines (electrode wirings) are preferably driven by separate control systems. By driving the two divided segment lines with their respective display drivers,
Existing control devices and control methods can be used, and manufacturing costs can be kept low.

FIG. 3 is a conceptual diagram of a display showing a third configuration example of the present invention. In this example, the first configuration example of FIG. 1 and the second configuration example of FIG. 2 are used in combination. That is, the screen is vertically divided into two, and the segment lines seg-1 to seg-5 of each system are divided into two systems. Here, the upper and lower pixels 21-1, 21-n
And 51-1 to 51-n are the wirings 3 for the respective electrodes.
2, 31 and 62, 61, respectively, and are connected to upper and lower terminals 32a, 31a and 62a, 61a of the screen, respectively. In the illustrated example, one system of pixels is alternately connected to two electrode wirings, but may be divided vertically and connected to each other, or an irregular connection method may be adopted. However, in consideration of the influence of the electric resistance of the electrode wiring, it is preferable to alternately connect the wirings as shown in the illustrated example.

Thus, for example, the scanning line 240 ×
The display surface of the data line 320 can be driven at a duty ratio of 1/60, and the driving time per scanning line can be quadrupled, and the instantaneous light emission luminance per pixel can be reduced accordingly. , Electrical and thermal stress can be reduced, and the life of the device can be extended. Further, the scanning time can be further shortened, which is advantageous in increasing the light emission luminance of the display surface and achieving higher definition.

FIGS. 4 and 5 show a fourth embodiment of the present invention. FIG. 4 is a sectional view, and FIG. 5 is a conceptual view showing a planar structure.

In the illustrated example, two electrode wirings 102, 1
04 or 81, 82 and 83, 84 are three-dimensionally arranged. In this way, by arranging the electrode wiring in a three-dimensional manner, the space required for the electrode wiring between pixels can be reduced, and each of the pixels 71-1 to 71-1 can be reduced accordingly.
-4 can be increased. Such a three-dimensional structure
This is particularly effective when two or more electrode wirings are required for each row or column element as shown in FIGS.

In FIG. 4, barrier layers 103, 104 are formed around electrode wirings 102, 104 formed on a substrate 101 for the purpose of preventing oxidation and the like and interference with other electrodes and the like. 105 is formed. In addition, as a manufacturing process, after forming the lower electrode wiring 102 and the barrier layer 103, forming the first insulating layer 106, further forming the upper electrode wiring 104 and the barrier layer 105, The second insulating layer 107 is formed. Finally, the pixel part and the contact hole (the part where the electrode is exposed)
By forming a hole injection electrode 108 of ITO or the like, conduction between each pixel and the electrode wirings 102 and 104 is achieved. Although the barrier layer is provided in the illustrated example, it is not always necessary and may not be provided depending on conditions.

Although FIG. 4 illustrates that the left and right pixel portions and the contact hole portions are connected from the same position, actually, as shown in FIG. The contact holes of the upper and lower electrode wires may be alternately formed and connected to the left and right pixels. In FIG. 5, upper and lower electrode wirings 81 and 82 or 83 and 84 are respectively connected to terminals 82a (81a
Are omitted) or 83a, 84a. Therefore, the system of each data line, seg-n to seg-n + 2
Are formed by a lower layer 82 and an upper layer 83 of adjacent electrode wires, and their terminal electrodes 82a, 83a.

As described above, by separating the display surface into a plurality of drive systems and independently driving each of them, it is possible to increase the light emission luminance and the definition, thereby realizing a higher quality display. It is possible to realize a screen of a size that has been conventionally difficult to use or a fine screen.

In the above example, the description has been made centering on the case of dividing into two or four in each mode. However, the number of divisions may be further increased. The number of divisions may be appropriately determined according to the size of the screen, the manufacturing cost, the characteristics of the light emitting element, and the like.

The number of scanning electrodes and the number of data electrodes in the matrix are appropriately determined according to the size and definition of the display.
The number of data electrodes is 0, and the number of data electrodes is about 1 to 2048 (in the case of color display, it is about three times), but the present invention is more effective as the number of scanning electrodes is larger. The size of one pixel is usually about 30 to 5000 μm, and the interval between pixels is about 0.5 to 200 μm.

The size of the electrode wiring is 0.1 to 0.1
The thickness is about 100 μm and the thickness is about 5 to 1000 nm. The width of the barrier layer is substantially equal to or greater than the width of the electrode wiring. The total thickness of the electrode wiring and the barrier layer is 10 to 2
It is about 000 nm.

As the metal material constituting the electrode wiring,
For example, Al, Al and transition metals, especially Sc, Nb,
Zr, Hf, Nd, Ta, Cu, Si, Cr, Mo, M
Preferred examples include aluminum-based alloys which may contain n, Ni, Pd, Pt, W, and the like, preferably a total of 10 at% or less, particularly 5 at% or less, particularly 2 at% or less. Aluminum has a low resistance, and when used as an electrode wiring layer, a good effect can be obtained.

It is preferable that the barrier layer has sufficient etching resistance to the etchant of the electrode wiring layer. Specifically, nitrides such as titanium nitride, molybdenum nitride, tantalum nitride, and chromium nitride; cobalt silicide, chromium silicide, molybdenum silicide,
Preferable examples include silicide compounds such as tungsten silicide and titanium silicide; titanium carbide, doped silicon carbide, and chromium. Of these, nitrides and chromium are preferred, and particularly titanium nitride,
Chromium is preferred. Titanium nitride has high corrosion resistance and has a large effect as an underlayer. The nitriding rate of TiN is 10 to 5
About 5% is preferable. Further, the above-mentioned silicide, oxide and the like usually exist in a stoichiometric composition, but may be slightly deviated from this.

A circuit for driving the main body of the organic EL display has a main control means 111 for giving data to be displayed on the display and data relating to the display as shown in FIG. 6, for example. Scanning electrodes of an organic EL display according to display data
Display control means 11 for transmitting a scan electrode drive signal and a data electrode drive signal which are signals for driving data electrodes
2 Further, it is connected to the display control means 112, and is used for expanding display data provided from the main control means 111 and the like into matrix data, bitmap data, etc., and display data for storing data of predetermined display contents and the like. A storage electrode 113, a scan electrode drive signal 114 for driving a scan electrode and a data electrode of an organic EL structure (organic EL display main body) 116 by a scan electrode drive signal and a data electrode drive signal from the display control means 112, Electrode driving means 115
And

The main control means 111 includes the organic EL structure 11
6, display data to be displayed, or designation of display data stored in the display data storage unit 113,
Gives timing and control data necessary for display.
The control means 111 can be generally constituted by a general-purpose microprocessor (MPU) and a control algorithm on a storage medium (ROM, RAM, etc.) connected to the MPU.

The main control means 111 includes CISC, RIS
It can be used irrespective of the mode of the processor such as C and DSP, and may be configured by a combination of logic circuits such as ASIC. In this example, the main control unit 111 is provided independently, but the display control unit 112,
It may be integrated with the control means of the device provided with the display.

The display control means 112 analyzes display data and the like provided from the main control means 111 and the like, searches data stored in the display data storage means 113 if necessary, and stores the display data on the organic EL display. Is converted into matrix data to be displayed at a predetermined position. That is, when the image (image or character) data to be displayed is dot data in pixel units of the organic EL element given at the intersection of each matrix, a signal for driving the scanning electrode and the data electrode giving the dot coordinates is provided. appear. In addition, driving in units of frames as described above, driving ratio (duty) control between the scanning electrodes and the data electrodes, and the like are also performed.

The display control means 112 includes, for example,
A processor or a complex logic circuit having a predetermined arithmetic function, a buffer for the processor or the like to exchange data with an external main control unit or the like, a timing signal to a control circuit,
A timing signal generating circuit (oscillation circuit) for giving a display timing signal and reading / writing to external storage means and a writing timing signal, a storage element control circuit for sending and receiving display data and the like from an external storage means, and reading from an external storage element Or a drive signal transmission circuit for transmitting display data, which is supplied from the outside or obtained by processing the data, as a drive signal, and stores data relating to a display function and a display to be externally supplied, control commands, and the like. It can be composed of various registers and the like.

The display data storage means 113 stores data (conversion table) for developing image data supplied from the outside as matrix data on a display,
Data in which predetermined character data and image data are directly expanded into matrix data and the like are stored, and can be read (written) by designating a storage position (address) as necessary.
Such a display data storage means is a RAM (VR
AM), and a semiconductor storage element such as a ROM can be preferably mentioned, but the present invention is not limited to this, and a storage medium using light or magnetism may be used.

The scanning electrode driving means 114 and the data electrode driving means 115 drive the scanning electrodes and the data electrodes according to the scanning electrode driving signal and the data electrode driving signal given from the display control means 2. The organic EL element constituting the organic EL display is a light emitting element that emits light by current driving. Therefore, the scan electrode drive signal and the data electrode drive signal, which are usually given as voltage signals, are converted into signals of a predetermined current value, and the signals are supplied to predetermined scan electrodes and data electrodes for driving.

More specifically, a scanning electrode and a data electrode at a predetermined position are driven by using a voltage-current conversion element having a necessary current capacity, an amplification element (power amplification), or the like. Examples of such a driving circuit include an open drain, an open collector circuit, a totem pole connection, a push-pull connection, and the like. A contact device such as a relay may be used as the voltage-current conversion element or the amplifying element. However, in consideration of high-speed operation and reliability, transistors, FETs, and semiconductors having functions equivalent to these are used. Elements are preferred. These semiconductor elements are
The scanning electrode and the data electrode are connected to either the power supply side or the ground side. Here, the power supply side and the ground side include not only a case where the power supply side and the ground side are directly connected to the power supply and the ground line, but also a case where the power supply side and the ground side are connected via elements such as a current limiting resistor, a protection device and a regulator.

In the present invention, among the above circuit components, in particular, the display control means 112 and the display data storage means 11
By appropriately adjusting the number 3, one screen can be divided and driven for each of a plurality of systems, and the displayed screen can be unified.

The above circuit is merely an example of a circuit configuration for driving each organic EL element (organic EL display main body), and other circuit configurations may be used as long as they have equivalent functions. Further, the display control means, the scan electrode driving means, the data electrode driving means and the like may be completely integrated without being clearly divided. Note that these circuit devices are generally configured as one or more types of ICs and peripheral components thereof.

Next, the organic EL device of the present invention will be described. The organic EL device of the present invention has a configuration in which a hole injection electrode, a hole injection / transport layer, a light emitting and electron injection / transport layer, an electron injection electrode, a protective layer and the like are stacked on a substrate.

The organic EL device of the present invention is not limited to the above-described configuration examples, but can be of various configurations. For example, a light-emitting layer is provided alone, and electron injection and transport are performed between the light-emitting layer and the electron injection electrode. A structure in which layers are interposed can also be used. Also,
If necessary, the hole injection / transport layer and the light emitting layer may be mixed.

The hole injection electrode is usually formed as the first electrode on the substrate side, and is configured to extract emitted light. Therefore, a transparent or translucent electrode is preferable. As the transparent electrode, ITO (tin-doped indium oxide), IZO (zinc-doped indium oxide), ZnO, SnO ₂ , In ₂
O _{3 and the} like can be mentioned, and preferably, ITO (tin-doped indium oxide), IZO (zinc-doped indium oxide)
Is preferred. ITO usually contains In ₂ O ₃ and SnO in a stoichiometric composition, but the amount of O may slightly deviate from this.

The thickness of the hole injecting electrode may be a certain thickness or more that can sufficiently inject holes, and is preferably 1 or more.
The range is preferably from 0 to 500 nm, more preferably from 30 to 300 nm.

The hole injection electrode layer can be formed by a vapor deposition method or the like, but is preferably formed by a sputtering method.

As the electron injection electrode, a substance having a low work function is preferable. For example, K, Li, Na, Mg, La, C
e, Ca, Sr, Ba, Al, Ag, In, Sn, Z
It is preferable to use a single metal element such as n or Zr, or a two-component or three-component alloy system containing them for improving the stability. Note that the electron injection electrode can be formed by an evaporation method or a sputtering method.

The thickness of the electron injecting electrode thin film may be a certain thickness or more capable of sufficiently injecting electrons.
Preferably, the thickness may be 1 nm or more. The upper limit is not particularly limited, but the thickness may be generally about 1 to 500 nm. A protective electrode may be further provided on the electron injection electrode.

After forming the electrode, in addition to the protective electrode, S
inorganic materials iO _X such as Teflon, a protective film may be formed using an organic material such as fluorocarbon polymers containing chlorine. The protective film may be transparent or opaque, and the thickness of the protective film is about 50 to 1200 nm. The protective film may be formed by a general sputtering method, an evaporation method, a PECVD method, or the like, in addition to the reactive sputtering method.

Further, it is preferable to provide a sealing plate on the element in order to prevent oxidation of the organic layer and the electrode of the element. The sealing plate adheres and seals the sealing plate using an adhesive resin layer in order to prevent moisture from entering. The sealing gas is Ar, H
e, an inert gas such as N _{2 and the} like are preferable.

The material of the substrate is not particularly limited, and can be appropriately determined according to the material of the electrodes of the organic EL structure to be laminated. For example, a metal material such as Al, or a transparent or transparent material such as glass, quartz, or resin. The material may be translucent or opaque. In this case, in addition to glass, ceramics such as alumina, metal sheets such as stainless steel are subjected to insulation treatment such as surface oxidation, and thermosetting resins such as phenolic resin And a thermoplastic resin such as polycarbonate.

Next, the organic layer of the organic EL device will be described. The light emitting layer has a function of injecting holes (holes) and electrons, a function of transporting them, and a function of generating excitons by recombination of holes and electrons. It is preferable to use a relatively electronically neutral compound for the light emitting layer.

The hole injecting and transporting layer has a function of facilitating the injection of holes from the hole injecting electrode, a function of stably transporting holes, and a function of preventing electrons.
The electron injection / transport layer has a function of facilitating the injection of electrons from the negative electrode, a function of stably transporting electrons, and a function of preventing holes. These layers increase and confine holes and electrons injected into the light emitting layer, optimize the recombination region, and improve luminous efficiency.

The thickness of the light emitting layer, the thickness of the hole injecting and transporting layer, and the thickness of the electron injecting and transporting layer are not particularly limited, and vary depending on the forming method.
It is preferable that the thickness be in the range of 10 to 300 nm.

The thickness of the hole injecting and transporting layer and the thickness of the electron injecting and transporting layer depend on the design of the recombination / light emitting region, but may be about the same as the thickness of the light emitting layer or about 1/10 to 10 times. When the hole or electron injection layer and the transport layer are separated from each other, it is preferable that the injection layer has a thickness of 1 nm or more and the transport layer has a thickness of 1 nm or more. At this time, the upper limit of the thickness of the injection layer and the transport layer is usually about 500 nm for the injection layer and 500 nm for the transport layer.
It is about. Such a film thickness is the same when two injection / transport layers are provided.

The light emitting layer of the organic EL device contains a fluorescent substance which is a compound having a light emitting function. Examples of such a fluorescent substance include, for example, JP-A-63-26469.
No. 2 discloses at least one compound selected from compounds such as quinacridone, rubrene, and styryl dyes. Also, Tris (8
Quinolinol derivatives such as metal complex dyes having 8-quinolinol or a derivative thereof as a ligand, such as (quinolinolato) aluminum; tetraphenylbutadiene, anthracene, perylene, coronene, and 12-phthaloperinone derivatives. Further, a phenylanthracene derivative described in JP-A-8-12600 (Japanese Patent Application No. 6-110569) and a phenylanthracene derivative described in JP-A-8-12969 (Japanese Patent Application No.
-114456) can be used.

Further, it is preferable to use in combination with a host substance capable of emitting light by itself, and it is preferable to use it as a dopant. In such a case, the content of the compound in the light emitting layer is 0.01 to 10% by weight, and more preferably 0.1 to 10% by weight.
It is preferably 1 to 5% by weight. When used in combination with a host substance, the emission wavelength characteristics of the host substance can be changed, light emission shifted to a longer wavelength becomes possible, and the luminous efficiency and stability of the device are improved.

The host substance is preferably a quinolinolato complex, and more preferably an aluminum complex having 8-quinolinol or a derivative thereof as a ligand. Such an aluminum complex is disclosed in JP-A-63-26469.
No. 2, JP-A-3-255190, JP-A-5-7073
3, JP-A-5-258859, JP-A-6-2158
No. 74 and the like.

Specifically, first, tris (8-quinolinolato) aluminum, bis (8-quinolinolato) magnesium, bis (benzo {f} -8-quinolinolato) zinc, bis (2-methyl-8-quinolinolato) aluminum Oxide, tris (8-quinolinolato) indium,
Tris (5-methyl-8-quinolinolato) aluminum, 8-quinolinolatolithium, tris (5-chloro-
8-quinolinolato) gallium, bis (5-chloro-8-
Quinolinolato) calcium, 5,7-dichloro-8-quinolinolatoaluminum, tris (5,7-dibromo-
8-hydroxyquinolinolato) aluminum and poly [zinc (II) -bis (8-hydroxy-5-quinolinyl) methane].

In addition to 8-quinolinol or its derivative, an aluminum complex having another ligand may be used.

Other host materials are disclosed in
Phenylanthracene derivative described in JP-A-12600 (Japanese Patent Application No. 6-110569) and JP-A-8-1296
No. 9 (Japanese Patent Application No. 6-114456) is also preferable.

The light emitting layer may also serve as an electron injection / transport layer. In such a case, it is preferable to use tris (8-quinolinolato) aluminum or the like. These fluorescent substances may be deposited.

The light emitting layer is preferably a mixed layer of at least one kind of hole injecting and transporting compound and at least one kind of electron injecting and transporting compound, if necessary.
Further, it is preferable that a dopant is contained in the mixed layer. The content of the compound in such a mixed layer is preferably 0.01 to 20% by weight, more preferably 0.1 to 15% by weight.

In the mixed layer, a carrier hopping conduction path is formed, so that each carrier moves in a substance having a favorable polarity and injection of a carrier having the opposite polarity is unlikely to occur, so that the organic compound is less likely to be damaged. This has the advantage that the element life is extended. Further, by including the above-described dopant in such a mixed layer, the emission wavelength characteristics of the mixed layer itself can be changed, the emission wavelength can be shifted to a longer wavelength, and the emission intensity is increased, The stability of the device can be improved.

The hole injecting / transporting compound and the electron injecting / transporting compound used in the mixed layer may be selected from a compound for a hole injecting / transporting layer and a compound for an electron injecting / transporting layer, respectively, which will be described later. Among them, compounds for the hole injection transport layer include amine derivatives having strong fluorescence,
For example, it is preferable to use a triphenyldiamine derivative which is a hole transport material, a styrylamine derivative, or an amine derivative having an aromatic condensed ring.

As the compound capable of injecting and transporting electrons, it is preferable to use a quinoline derivative, furthermore a metal complex having 8-quinolinol or its derivative as a ligand, particularly tris (8-quinolinolato) aluminum (Alq3). It is also preferable to use the above-mentioned phenylanthracene derivatives and tetraarylethene derivatives.

The mixing ratio in this case depends on the respective carrier mobilities and carrier concentrations. In general, the weight ratio of the compound of the hole injection / transport compound / the compound having the electron injection / transport function is from 1/99 to less. 99/1, more preferably 10/90 to 90/10, particularly preferably 20/80
It is preferable to set it to about 80/20.

The thickness of the mixed layer is preferably not less than the thickness corresponding to one molecular layer and less than the thickness of the organic compound layer. Specifically, the thickness is preferably 1 to 85 nm, more preferably 5 to 60 nm, particularly preferably 5 to 50 nm.

As a method of forming a mixed layer, co-evaporation in which evaporation is performed from different evaporation sources is preferable. However, when the vapor pressures (evaporation temperatures) are the same or very close, the mixed layers are previously mixed in the same evaporation board. Alternatively, it can be deposited. In the mixed layer, it is preferable that the compounds are uniformly mixed, but in some cases, the compounds may exist in an island shape. The light-emitting layer is generally formed to a predetermined thickness by vapor-depositing an organic fluorescent substance or by dispersing and coating the resin in a resin binder.

The hole injecting and transporting layer is described in, for example, JP-A-63-295695 and JP-A-2-19169.
4, JP-A-3-792, JP-A-5-234
681, JP-A-5-239455, JP-A-5-299174, JP-A-7-126225, JP-A-7-126226, JP-A-8-100
Various organic compounds described in JP-A-172, EP0650955A1, and the like can be used. For example, a tetraarylbendicine compound (triaryldiamine or triphenyldiamine: TPD), an aromatic tertiary amine, a hydrazone derivative, a carbazole derivative, a triazole derivative, an imidazole derivative, an oxadiazole derivative having an amino group, polythiophene, etc. . These compounds may be used alone or in combination of two or more. When two or more kinds are used in combination, they may be stacked as separate layers or mixed.

The electron injecting / transporting layer includes a quinoline derivative such as an organometallic complex having 8-quinolinol such as tris (8-quinolinolato) aluminum (Alq3) or a derivative thereof as a ligand, an oxadiazole derivative, a perylene derivative, or the like. A pyridine derivative, a pyrimidine derivative, a quinoxaline derivative, a diphenylquinone derivative, a nitro-substituted fluorene derivative, or the like can be used. The electron injection / transport layer may also serve as the light emitting layer. In such a case, it is preferable to use tris (8-quinolinolato) aluminum or the like. The electron injecting and transporting layer may be formed by vapor deposition or the like, similarly to the light emitting layer.

In the organic layer, a hole injection / transport layer, an electron injection / transport layer, etc. may be formed of an inorganic material.

The emission color may be controlled by using a color filter film, a color conversion film containing a fluorescent substance, or a dielectric reflection film on the substrate.

As the color filter film, a color filter used in a liquid crystal display or the like may be used.
The characteristics of the color filter may be adjusted in accordance with the light emitted from the organic EL element to optimize the extraction efficiency and the color purity.

When a color filter capable of cutting off short-wavelength external light that is absorbed by the EL element material or the fluorescence conversion layer is used, the light resistance of the element and the display contrast are improved.

Further, an optical thin film such as a dielectric multilayer film may be used instead of the color filter.

The fluorescence conversion filter film absorbs EL light and emits light from the phosphor in the fluorescence conversion film to convert the color of the emitted light. It is formed from a fluorescent material and a light absorbing material.

As the fluorescent material, basically, a material having a high fluorescence quantum yield may be used, and it is desirable that the fluorescent material has strong absorption in the EL emission wavelength region. In practice, laser dyes and the like are suitable, and rhodamine compounds, perylene compounds, cyanine compounds, phthalocyanine compounds (including subphthalocyanines, etc.) naphthaloimide compounds, condensed ring hydrocarbon compounds, condensed heterocyclic compounds A styryl compound, a coumarin compound or the like may be used.

As the binder, a material that does not quench the fluorescence may be basically selected, and a binder that can be finely patterned by photolithography, printing, or the like is preferable. Further, a hole injection electrode formed on the upper layer, for example, I
It is preferable to use a material that is not damaged during the film formation of TO and IZO.

The light absorbing material is used when the light absorption of the fluorescent material is insufficient, but may be omitted when unnecessary. As the light absorbing material, a material that does not quench the fluorescence of the fluorescent material may be selected.

For forming the hole injection transport layer, the light emitting layer and the electron injection transport layer, a uniform thin film can be formed.
It is preferable to use a vacuum deposition method. When vacuum deposition is used, the amorphous state or the crystal grain size is 0.1 μm
The following homogeneous thin film is obtained. If the crystal grain size exceeds 0.1 μm, the light emission becomes non-uniform, the driving voltage of the device must be increased, and the charge injection efficiency is significantly reduced.

The conditions for vacuum deposition are not particularly limited.
The degree of vacuum is 0 ^-4 Pa or less, and the deposition rate is 0.01 to 1 nm /
It is preferable to set it to about sec. Further, it is preferable to form each layer continuously in a vacuum. If they are formed continuously in a vacuum, impurities can be prevented from adsorbing at the interface between the layers, so that high characteristics can be obtained. Further, the driving voltage of the element can be reduced, and the occurrence and growth of dark spots can be suppressed.

When a plurality of compounds are contained in one layer when a vacuum evaporation method is used to form each of these layers, it is preferable to co-deposit each boat containing the compounds by individually controlling the temperature.

The driving current of the organic EL device is preferably about 0.001 to 100 mA, particularly about 0.01 to 50 mA.

[0087]

<Example 1> After a wiring for an electrode was formed on a glass substrate, a passivation film (SiO ₂ ) was formed (patterned) except for the wiring for an electrode and a light emitting portion. Thereafter, an ITO transparent electrode (hole injection electrode) was formed to a thickness of about 100 nm by a sputtering method. The obtained ITO thin film was patterned and etched by a photolithographic technique to form a hole injection electrode layer constituting a 240 × 320 dot (pixel) pattern.

At this time, the wiring structure was divided into upper and lower two parts as shown in FIG. 1 (Sample 1), and the wiring structure was made into two upper and lower parts and two parallel electrode wirings as shown in FIG. 3 (Sample 2). The electrode wiring of FIG. 3 is simply a multilayer structure as shown in FIG. 4 (sample 3), the electrode wiring of FIG. 3 is multilayered, and the data lines are divided into four as two parallel electrode wirings. A sample (Sample 4) was produced. Also,
As a comparative example, one having no divided structure (comparative sample) was also produced.

After the surface of the substrate on which the ITO transparent electrodes, electrode wirings, etc. are formed is subjected to UV / O ₃ cleaning, a mask for vapor deposition is mounted, and the substrate is fixed to a substrate holder of a vacuum vapor deposition apparatus. The pressure was reduced.

4,4 ′, 4 ″ -tris (-N- (3-methylphenyl) -N-phenylamino) triphenylamine (hereinafter referred to as m-MTDATA) was deposited to a thickness of 40 nm, and a hole injection layer was formed. And then, while maintaining the reduced pressure,
N, N'-diphenyl-N, N'-m-tolyl-4,
4'-diamino-1,1'-biphenyl (hereinafter referred to as TP
D) was deposited to a thickness of 35 nm to form a hole transport layer. Further, while maintaining the reduced pressure, tris (8-quinolinolato)
Aluminum (hereinafter, Alq3) was deposited to a thickness of 50 nm to form an electron injecting / transporting / light emitting layer.

Then, while maintaining the reduced pressure, the EL element structure substrate was transferred from the vacuum evaporation apparatus to the sputtering apparatus, and the AlLi electron injection electrode (Li concentration: 7.2 at%) was formed to a thickness of 50 nm at a sputtering pressure of 1.0 Pa. Then, a film was formed. At that time, Ar was used as a sputtering gas, the input power was 100 W, the size of the target was 4 inches in diameter, and the distance between the substrate and the target was 90 mm. Further, while maintaining the reduced pressure, the EL
The element substrate was transferred to another sputtering apparatus, and the Al protective electrode was set to 200 nm by DC sputtering using an Al target.
Was formed to a thickness of The mask was removed when all film formation was completed.

Finally, a glass sealing plate was attached, and organic E
L display.

Each of the obtained organic EL displays was applied with a DC voltage in the air and driven under an acceleration condition of 400 cd / m ² per pixel, and a change in light emission luminance after 5000 hours was measured.

As a result, Sample 1 had a drive duty of 1/120 and 30% of the initial luminance, Sample 2 had a drive duty of 1/60 and 50% of the initial luminance, and Sample 3 had a drive duty of 1/60 and 60% of the initial luminance. Sample 4 was able to maintain a light emission luminance of 70% of the initial luminance at a drive duty of 1/30. On the other hand, in the comparative sample, the initial emission luminance was obtained only up to 200 cd / m ² at the drive duty of 1/240.

<Embodiment 2> In Embodiment 1, segment-type elements are connected to one of the drive lines on the scanning electrode side by the number of data lines, and each data line is connected to each segment element. Are connected, and the data lines are driven so as to make these selections.

As a result, it was confirmed that the same effect as in the first embodiment can be obtained even when the segment element is driven.

[0097]

As described above, according to the present invention, it is possible to increase the signal width of each scanning line (decrease the drive duty ratio) and to reduce the instantaneous luminance.
It is possible to realize an organic EL display device capable of reducing electrical and thermal damage to the element and maintaining the initial performance of the element for a long period of time.

Further, even when a large screen or a high-definition display screen is provided, a necessary light emission luminance can be ensured, and therefore, an organic EL display device capable of obtaining a high-quality and high-definition display can be realized.

Further, it is possible to realize an organic EL display device capable of further increasing the emission luminance and obtaining a higher definition display screen.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a first configuration example of the present invention.

FIG. 2 is a schematic plan view showing a second configuration example of the present invention.

FIG. 3 is a schematic plan view showing a third configuration example of the present invention.

FIG. 4 is a schematic sectional view showing a fourth configuration example of the present invention.

FIG. 5 is a schematic plan view showing a fourth configuration example of the present invention.

FIG. 6 is a block diagram illustrating an example of a drive circuit of the organic EL display device.

[Explanation of symbols]

 11 upper screen 12 lower screen 31, 32 electrode wiring 21-1 to n pixel 31a, 32a terminal seg-1 to 5 data line 61, 62 electrode wiring 51-1 to n pixel 61a, 62a terminal 81, 83 electrode Wiring (upper) 82,84 Wiring for electrode (lower)

Continuation of the front page (72) Inventor Shun Tanaka 1-1-13 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation (72) Inventor Hiroshi Yamamoto 1-13-1 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation F-term (reference)

Claims (23)

[Claims] 1. An organic EL display device having individual organic EL elements defined as a combination of row and column elements, wherein at least one of the rows and columns is driven by two or more drive systems. Organic EL display device. 2. The organic EL display device according to claim 1, wherein the two or more drive systems are driven with a duty smaller than a display resolution in a direction in which the entire screen is scanned. 3. The organic EL display device according to claim 1, wherein the row or column element driven by the two or more drive systems is on the scanning electrode side. 4. An organic EL element in one row or column element is divided into a system corresponding to a plurality of electrode wirings, and each of the divided pixels corresponds to a corresponding one of the electrodes. The organic EL display device according to claim 1, wherein the organic EL display device is connected to a wiring for use. 5. The organic EL display device according to claim 1, wherein the number of said electrode wires is larger than the number of corresponding row or column elements. 6. The organic EL according to claim 5, wherein the number of the electrode wirings is an integral multiple of the number of the corresponding row or column elements.
Display device. 7. The organic EL in one row or column element
The organic EL display device according to any one of claims 4 to 6, wherein the elements are sequentially and alternately connected to each electrode wiring. 8. The electrode wiring is composed of one pixel, the organic E
8. The organic EL device according to claim 7, wherein two organic EL devices are arranged on both sides of the L element.
Display device. 9. The organic EL display device according to claim 1, wherein said electrode wiring has a three-dimensionally arranged multilayer structure. 10. An electrode according to claim 1, wherein said electrode wiring is an organic E
7. The organic EL display device according to claim 1, wherein the organic EL display device has a multilayer structure three-dimensionally arranged on one side of the L element. 11. The organic EL display device according to claim 9, wherein two of said electrode wirings are arranged on both sides of an organic EL element as one pixel and have a three-dimensionally arranged multilayer structure. 12. The organic EL display device according to claim 1, which is a display of a simple matrix and / or segment type. 13. An organic EL display device having individual organic EL elements defined as a combination of row and column elements, wherein at least one of the row and column is driven by two or more drive systems, An organic EL display device in which each organic EL element of this row or column element is divided into a system corresponding to the electrode wiring, and each of the divided organic EL elements is connected to each corresponding electrode wiring. . 14. The organic EL display device according to claim 13, wherein the row or column element driven by the two or more drive systems is on the scanning electrode side. 15. The organic EL display device according to claim 13, wherein the two or more drive systems are driven with a duty smaller than a display resolution in a scanning direction of the entire screen. 16. The organic EL display device according to claim 13, wherein the number of the electrode wires is larger than the number of the corresponding row or column elements. 17. The organic EL display device according to claim 16, wherein the number of the electrode wirings is an integral multiple of the number of the corresponding row or column elements. 18. The organic E in one row or column element.
18. The organic EL display device according to claim 13, wherein L elements are sequentially and alternately connected to each electrode wiring. 19. The organic EL display device according to claim 18, wherein two electrode wirings are arranged on both sides of the organic EL element as one pixel. 20. The organic EL display device according to claim 13, wherein said electrode wiring has a multilayer structure arranged three-dimensionally. 21. An electrode according to claim 1, wherein the electrode wiring is a pixel.
19. The organic EL display device according to claim 13, wherein the organic EL display device has a multilayer structure three-dimensionally arranged on one side of the L element. 22. The organic EL display device according to claim 20, wherein two of said electrode wirings are arranged on both sides of an organic EL element as one pixel and have a three-dimensionally arranged multilayer structure. 23. The organic EL display device according to claim 13, which is a display of a simple matrix and / or segment type.