GB2337354A - Drive circuit for electroluminescent display providing uniform brightness - Google Patents
Drive circuit for electroluminescent display providing uniform brightness Download PDFInfo
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- GB2337354A GB2337354A GB9910680A GB9910680A GB2337354A GB 2337354 A GB2337354 A GB 2337354A GB 9910680 A GB9910680 A GB 9910680A GB 9910680 A GB9910680 A GB 9910680A GB 2337354 A GB2337354 A GB 2337354A
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- 239000011521 glass Substances 0.000 description 6
- 230000005525 hole transport Effects 0.000 description 6
- 238000004020 luminiscence type Methods 0.000 description 6
- 229910052749 magnesium Inorganic materials 0.000 description 5
- 238000005530 etching Methods 0.000 description 4
- 150000002894 organic compounds Chemical class 0.000 description 4
- 238000007789 sealing Methods 0.000 description 4
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- 239000010409 thin film Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 241000206754 Palmaria palmata Species 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000009849 deactivation Effects 0.000 description 2
- 239000002019 doping agent Substances 0.000 description 2
- 239000001921 dulse Substances 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 206010011416 Croup infectious Diseases 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- NRCMAYZCPIVABH-UHFFFAOYSA-N Quinacridone Chemical compound N1C2=CC=CC=C2C(=O)C2=C1C=C1C(=O)C3=CC=CC=C3NC1=C2 NRCMAYZCPIVABH-UHFFFAOYSA-N 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- APLQAVQJYBLXDR-UHFFFAOYSA-N aluminum quinoline Chemical compound [Al+3].N1=CC=CC2=CC=CC=C12.N1=CC=CC2=CC=CC=C12.N1=CC=CC2=CC=CC=C12 APLQAVQJYBLXDR-UHFFFAOYSA-N 0.000 description 1
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- 229910052738 indium Inorganic materials 0.000 description 1
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Classifications
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3216—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using a passive matrix
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0233—Improving the luminance or brightness uniformity across the screen
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0285—Improving the quality of display appearance using tables for spatial correction of display data
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/2007—Display of intermediate tones
- G09G3/2011—Display of intermediate tones by amplitude modulation
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/2007—Display of intermediate tones
- G09G3/2014—Display of intermediate tones by modulation of the duration of a single pulse during which the logic level remains constant
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
- Electroluminescent Light Sources (AREA)
- Control Of El Displays (AREA)
Abstract
A drive circuit for an EL display device capable of permitting picture cells of an EL display device to have a substantially equal current density, to thereby exhibit uniform luminance sufficient to provide display of the display device with increased quality, even when the picture cells are different in area, luminous color and/or luminous efficiency from each other. A luminance correction data storage section is stored therein with correction data corresponding to areas of the picture cells. The correction data of each picture cell corresponding to display data are read from the luminance correction data storage section, so that a current flowed between two electrode groups of the EL display device may be variably controlled for every picture cell while rendering a period of time during which the current is flowed therebetween constant, based on the correction data read. In an alternative embodiment, the time period of current flow is varied while the current flow remains constant.
Description
2337354 DRIVE CIRCUIT FOR ELECTROLUMINESCENT DISPLAY DEVICE This invention
relates to a drive circuit for an electroluminescent display device, and more particularly to a drive circuit for an electroluminescent display device wherein organic layers each made of an organic compound such as a hole transport layer, a luminous layer and the like are laminatedly arranged in a predetermined display pattern between a pair of electrode groups of which at least one is made of a transparent conductive layer.
An organic electroluminescent (hereinafter referred to as "EL") display device is constructed so as to interposedly arrange a thin film containing an organic compound between a cathode electrode and an anode electrode and inject electrons and positive holes into the thin film to recombine the electrons and positive holes with each other to produce excitons, resulting in light (fluorescence or luminescence) emitted from the excitons during deactivation thereof being utilized for display.
Now, a conventional EL display device in which such an organic EL device is incorporated will-be described with reference to Fig. 4. The EL display device includes a glass substrate 31 made of an insulating and light-permeable glass material and a transparent electrode made of indium tin oxide (ITO) and formed on the glass substrate 31. The transparent electrode 32 is laminatediv formed thereon with an organic layer 33, which is formed of a thin film made of an organic phosphor. The organic layer 33 includes a hole transport layer 33A and a luminous layer 33B formed on the transparent electrode 32 in order, resulting in being constructed into a two-layer structure and providing each of picture cells 34. The luminous layer 33B has a metal electrode 35 laminated on the luminous layer 33B. The metal electrode 35 is made of metal such as A!, Ag, Mg:Ag, AI:T.i or the lke.
L Ln the 1EL display de-j,-ice thus constructed, a voltage is annlied between the transDarent electrode 32 and the metalelectrode 35 while acting the transparent electrode 32 as.an anode electrode, resulting in a current of a constant level being flowed therebetween. This permits electrons and positive holes to be injected into the organic layer 33 from the transparent electrode 32 and metal electrode 35, respectively. Then, the electrons and positive holes thus injected are recombined together to produce excitons, so that light emitted from the excitons during deactivation of the excitons may provide desired luminous display.
The EL display device is driven while constantly flowing a current of a constant level to each of the picture cells rather than according to voltage driving, to thereby exhibit uniform luminescence and compensate a change of the elements with time.
However, when the EL display device is constructed so as to carry out display by a combination of picture cells different in area, constantcurrent driving causes luminance of the display to be inversely proportional to a luminous area, resulting in failing to permit the EL display device to exhibit uniform luminance, leading to a deterioration in quality of display. A similar problem arises when the picture cells are different in luminous color or luminous efficiency from each other.
The present invention has been made in view of the foregoing disadvantage of the prior art.
Accordingly, it is an object of the present invention to provide a drive circuit for an EL display device which is capable of permitting picture cells to exhibit uniform luminance irrespective of a difference in area, luminous color and/or luminous efficiency between the picture cells.
It is another object of the present invention to provide a drive circuit for an EL display device which Is capable of providing display with increased quality.
In accordance with the present invention, a drive circuit is provided for an EL display device which includes two electrode 9-1-oups of which at least one is made of a light-permeable material and organic layers 1aminatedly arranged between the two electrode croups so as to n-t-c-7ide picture cells different in are-a -umincus sect-4.on, wherein a voltage from each other acting as a - L is applied between the -Lwo electrode groups while acting one of L the two electrode groups as an anode, to thereby Permit a current J 1 1 i 1 of a predetermined level to be flowed between the two electrode groups, resulting in the EL display device carrying out desired display. The drive circuit includes a luminance correction data storage section having correction data which correspond to areas of the picture cells stored therein. The correction data of each of the picture cells corresponding to display data are read from the luminance correction data storage section, so that the current flowed between the electrode groups is variably controlled for every picture cell while rendering a period of time during which the current is flowed between the electrode groups constant, based on the correction data read.
Also, in accordance with the present invention, a drive circuit is provided for an EL display device which includes two electrode groups of which at least one is made of a lightpermeable material and organic layers laminatedly arranged between the two electrode groups so as to provide picture cells different in area from each other acting as a luminous section, wherein a voltage is applied between the two electrode groups while acting one of the two electrode groups as an anode, to thereby permit a current of a predetermined level to be flowed between the two electrode groups, resulting in the EL display device carrying out desired display. The drive circuit includes a luminance correction data storage section having correction data which correspond to areas of the picture cells stored thereJ-n. The correction data of each of the picture cells corresponding to display data are read from the luminance correction data storage section, so that a period of time during which the current is flowed between the electrode groups variably controlled for every picture cell while rendering a current flowed to each of the picture cells constant, based on the correction data read.
In a preferred embodiment of the present invention, the correction data depend on a luminous color of each of the picture 11-erna±iveiv, the correction data may depend on luminous ceLls. 'M- of each of the picture cells.
T4hese and othe-- objects and many o:f -he attendant advantages of the present invention will be readily appreciated R 1 as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings; wherein:
Fig. 1 is a plan view showing an EL display device in which a drive circuit according to the present invention may be incorporated by way of example; Fig. 2 is a fragmentary enlarged side elevation view in section of the EL display device shown in Fig. 1; Fig. 3 is a block diagram showing an embodiment of a drive circuit for an EL display device according to the present invention; and Fig. 4 is a sectional side elevation view schematically showing a conventional EL display device in which an organic EL display device is incorporated.
Now, a drive circuit for an EL display device according to the present invention will be described hereinafter with reference to the accompanying drawings.
Referring first to Fig. 1, an EL display device in which a drive circuit according to the present invention may be incorporated is illustrated by way of example. The EL display device includes an element substrate 1 of a rectangular shape acting as a base. The element substrate 1 is provided on a front surface thereof with a transparent electrode group 2, which is formed of a light-permeable material such as an ITO or the like -nto a substantially uniform thickness by etching, mask deposition or the like. In Fig. 1, the transparent electrode group 2 includes three transparent electrodes 2A arranged in a line on an upper row and three transparent electrodes 2B arranged in a line on a lower row, resulting in forming a 2row and 3column matrix. A part of each of the transparent electrodes 2A and 2B acts as a wiring, which is led out of each of the transparent electrodes 2A and 2B to an outside of the element substrate 1 and then connected to a data output circuit 17 of a drive circuit of the cresent invention described hereinafter.
The -L-ransDarent electrode group 2, as shown in Figs. 1 and 2, is laminatedly provided thereon with an insulating layer 3 of an increased resistance, which is made of, for example, epoxy 1 4 resin, frit glass or an organic silica compound by calcination and formed into a rectangular shape. The insulating layer 3 is provided with through sections 4, each of which is formed by boring a part of the insulating layer 3 into a shape corresponding to each of the transparent electrodes 2A and 2B, resulting in being patterned.
The insulating layer 3 is formed into a substantially uniform thickness by printing, mask deposition, etching or the like. More specifically, it may be formed by boring SiN or Si02 in a desired pattern by etching. Alternatively, it may be formed either by printing frit glass or an organic silica compound in a desired pattern, followed by calcination or by patterning heatresistant photosensitive resin in a predetermined configuration by photolithography.
The transparent electrodes 2A and 2B of the transparent electrode group 2, as shown in Fig. 2, each have an organic layer 5 laminatedly formed thereon so as to fill up each of the through sections 4 of the insulating layer 3. In Fig. 2, the organic layers 5 each are constructed into a twolayer structure including a hole transfer layer 5A made of an organic compound such as, for example, diamine or the like and a luminous layer 5B made of an organic compound, wherein the lamination is carried out in order of the hole transport layer 5A and luminous layer 5B.
The organic layers 5 each function at a portion thereof which fills up each of the through sections 4 of the insulating layer 3 as a picture cell 6 constituting a luminous section. In the illustrated embodiment, the picture cells 6 include three picture cells 6A arranged in a line on an upper row and three picture cells 6B arranged in a line on a lower row. The upper picture cells 6A each are formed into a square shape of a in length of one side and the lower picture cells 6B each are formed Jnto a rectangular shape having an area twice as large as that of Lhe upper picturs cell 6A. Luminescence of the organic layers 5 permits disp1Lay due to an array of the picture cells 6 to be cbserved through the element substrate 1.
The luminous layers 55B each may be made of a luminous material such as, for example, aluminum quinoline (Alq), distyryl allylene or the like when it is constructed so as to emit light by itself. Alternatively, it may be constructed so as to emit light by doping the luminous layer 5B with another luminous substance (dopant) in a trace amount. In this instance, quinacridon (Qd), a pigment for laser or the like may be used as. the dopant.
The luminous layers 5B, as shown in Fig. 1, each are laminatedly formed thereon with a metal electrode 7A or 7B so as to cover the picture cells 6A and 6B of each of two rows. The metal electrodes 7A and 7B thus formed constitute a metal electrode group 7. The metal electrodes 7A and 7B each are formed of Al, Ag, Mg:Ag, Al:Li or the like into a substantially uniform thickness by etching, mask deposition or the like. The metal electrode group 7 is connected to a scan output circuit 15 of the drive circuit 11 described hereinafter.
The element substrate, 1 has a sealing substrate 9 fixed on an outer peripheral portion thereof so as to act as a sealing member. Such fixing of the sealing substrate 9 on the element substrate 1 is carried out in an atmosphere from which water is removed to the utmost such as a dry inert gas atmosphere, a dry air atmosphere or the like. Nitrogen may be used as the inert gas. Such arrangement of the sealing substrate 9 ensures protection of the transparent electrode group 2, metal electrode group 7 and organic layers 5 and provides the organic EL display device with high definition.
In the EL display device of the illustrated embodiment, the transparent electrode group 2 and metal electrode group 7 are arranged in a manner contrary to that described above. In this instance, the element substrate 1 is not necessarily required to be transparent, therefore, it may be made of glass exhibiting -insulating properties. Also, in the illustrated embodiment, it ls merely required that at least one of the transparent electrode group 2 and metal electrode 7 is made of a light-permeable nater-ia-,.
;"he EL display device of the -'L-llus,'--ra-Led embodiment thus:7onstructed is operated in such a manner that a voltage is a-,,Dlied between each of the transDarent electrodes 2A and 2B and each of the metal electrodes 7a and 7B while acting one of the electrode groups 2 and 7 as an anode, to thereby permit a current of a constant level to be flowed between the transparent electrode group 2 and the metal electrode group 7, resulting in providing desired display. The anode may be constituted by, for example, the transparent electrode group 7.
The drive circuit 11 for driving the thus-constructed EL display device by means of a constant current, as shown in Fig. 3, generally includes a timing signal generating circuit 12, a data control section 13, a storage section 14 including a display data storage portion 14A and a luminance correction data storage portion 14B, the scan output circuit 15 briefly described above, an operation control circuit 16, and the data output circuit 17 briefly described above.
The timing signal generating circuit 12 functions to successively select and scan the metal electrodes 7A and 7B for every row and input a data signal to the transparent electrode group, so that desired display may be carried out. For this purpose, the timing signal generating circuit 12 outputs a predetermined timing signal to each of the data control section 13, storage section 14, scan output circuit 15 and operation control circuit 16.
The data control section 13 functions to timesequentially take in display data successively inputted thereto by means of the timing signal outputted from the timing signal generating circuit and then store the display data in the display data storage portion 14A. in Fig. 1, the display data are data for displaying, for example, alphabetical characters I'V, "Ivy, "L" and the like.
The luminance correction data storage portion 14B has luminance correction data which correspond to an area of each of the picture cells 6 stored therein in the form of a table. More particularly, a level of a voltage to be applied to a picture cell of a predetermined area is previously set to be reference data and correction data depending on a voltage level corresponding to an area of each of the picture cells 6 are stored in the form of a table based on the reference data.
Alternatively, a Dulse width of a voltage to be applied to a picture cell of a predetermined area is previously set to be reference data and correction data depending on a voltage level corresponding to an area of each of the picture cells 6 are stored in the form of a table based on reference data.
The scan output circuit 15 functions to successively select and scan the metal electrodes 7A and 7B of the EL display device for every row by means of the timing signal outputted from the timing signal generating circuit 12. In the EL display device shown in Fig. 1, the selection and scanning are carried out in order of the three metal electrodes 7A on the upper row and the three metal electrodes 7B on the lower row.
The operation control circuit 16 functions to read, from the luminance correction data storage portion 14B, correction data for every picture cell corresponding to display data read from the display data storage portion 14A by means of the timing signal outputted from the timing signal generating circuit 12.
In this instance, when a construction wherein the luminance correction data storage portion 14B has correction data based on a voltage level stored therein is employed, a level of a voltage inputted to a driver circuit of the data output circuit 17 is varied by the correction data read, so that an output current flowed between the transparent electrode group 2 and the metal electrode group 7 may be varied depending on an area of each of the picture cells 6. At this time, a period of time during which the current is flowed therebetween is kept constant. 1For example, supposing that an output current at the time when a voltage leve'L of the correction data inputted for driving the Dicture cells 6A for luminescence is set to be reference data is 5 mA / CM2, a voltage of a level twice as high as that of the reference data is inputted to the data output circuit 17 resulting in an output current thereof being 10 mA/ CM2.
On the contrary, when a construction wherein the luminance correction data storage portion 14B has correction data based on a pulse width stored therein is employed, a pulse width of a,,oltage inputted zo the driver circuit of the data output c-i-rcuit 17 is varied bj the correction data read, so that a period of time during which an output current is flowed between each of the transparent electrodes 2A and 2B and each of the metal elect--odes 7A and 7B may be varied. For example, supposing S that an output current at the time when a pulse width of the correction data inputted for driving the picture cells 6A for luminescence is set to be reference data is 5 mA/cm', a voltage of a pulse width twice as large as that of the reference data is inputted to the data output circuit 17, resulting in an output current thereof being 10 MA/CM2.
The data output circuit 17 functions to output a data signal for on-off operation of each of the picture cells 6 in synchronism with the scan output circuit 15. More specifically, the data output circuit 17 is constituted of a driver circuit including transistors of the constantcurrent drive type corresponding in number to the transparent electrodes 2A and 2B of the transparent electrode group 2. The data output circuit 17, as described above, is so constructed that an input voltage thereof is controlled so as to provide an output current corresponding to the correction data from the operation control circuit 16, resulting in a current of,a level depending on the area of the picture cell being flowed between each of the transparent electrodes 2A and 2B and each of the metal electrodes 7A and 7B.
Thus, the EL display device of the illustrated embodiment, even when the luminous section is constituted of the picture cells different in area, permits the picture cells 6 to have the same average current density, resulting in the picture cells exhibiting uniform luminance, so that the EL display device may provide display with increased quality.
in the illustrated embodiment, the organic layers 5 each are constructed into the two-layer structure including the hole transport layer 5A and luminous layer 5B. Alternatively, the organic layer 5 may be constituted by a combination of the luminous layer and a charge transport layer such as a positive transport layer, a hole injection/transport layer, an electron injection layer, an electron injection/transport layer or the Alternatively, it may be constructed into a single-layer s----ucture i=luding only the luminous layer, a two-layer structure including the luminous layer and hole transport layer or the luminous 'Layer and electron injection layer, a threelayer s-Lructure including the hole transport, luminous layer and 1 1 1 1 electron injection layer, or the like.
The electron injection layer may be made of elemental metal reduced in work function such as, for example, Li, Na, Mg, Ca or the like or alloy reduced in work function such as, for example, Al:Li, Mg:In, Mg:Ag or the like, to thereby facilitate injection of electrons thereinto.
A pattern of the picture cells 6 incorporated in the EL display device is not limited to that described above. It may be determined as desired depending on a configuration of the picture cells 6, an area thereof and the number thereof.
In the EL display device described above, the picture cells 6 includes the picture cells 6A and picture cells 6B different in area from each other. Alternatively, the picture cells may include picture cells different in luminous color and/or luminous efficiency from each other. In this instance, the luminance correction data storage portion 14B has luminance correction data for every luminous color or luminous efficiency of each of the picture cells 6 stored therein in the form of a table for every picture cell.
More particularly, the luminance correction data storage portion 14B is stored therein with a level or pulse width of a voltage to be applied for every luminous color or luminous efficiency of each of the picture cells 6 in the form of correction data. Correction data corresponding to display data permit an output of the data output circuit 17 to be controll ed so as to provide a current density corresponding to required luminance of each of the picture cells 6 as in the abovedescribed luminescence of the picture cells 6A and 6B different in area from each other. This permits a current of a constant level determined depending on the required luminance to be fed between each of the transparent electrodes 2A and 2B and each of the metal electrodes 7A and 7B.
Alternatively, the luminance correction data storage portion 14B is stcred therein with a level or Dulse width of a luminous color or luminous ;cl-l-.age to be applied for every area, efficiency o--P: each o-LE the picture cells 6 as correction data in 7-.-.e form of a table for every picture cell, so that correction data corresnonding to display data permit an output of the data 0 output circuit 17 to be controlled. The correction data may be in the form of a level or pulse width of a voltage corresponding to any combination of an area of each of the picture cells 6, a luminous color thereof and luminous efficiency thereof.
As can be seen from the foregoing, the present invention, even when the picture cells are different in area, luminous color and/or luminous efficiency from each other, permits the picture cells to have a substantially equal current density, resulting in the picture cells exhibiting uniform luminance, so that the display may be provided with increased quality.
C 1 a -l I 5z:
A drive circuit for an EL display device which includes two electrode groups of which at least one is made of a light-permeable material and organic layers laminatedly arranged between the two electrode groups so as to provide picture cells different in area from each other acting as a luminous section, wherein a voltage is applied thereto while acting one of the two electrode groups as an anode, to thereby permit a current of a predetermined level to be flowed between the two electrode groups, resulting in the EL display device carrying out desired display, comprising:
a luminance correction data storage section having correction data which correspond to areas of said picture cells stored therein; whereby the correction data of each of said picture cells corresponding to display data are read from said luminance correction data storage section, so that the current flowed between said electrode groups is variably controlled for every picture cell while rendering a period of time during which the current is flowed between said electrode groups constant, based on the correction data read.
2. A drive circuit as defined in claim 1, wherein said correction data depend on a luminous color of each of said picture cells.
3. A drive circuit as defined in claim 1, wherein said correction data depend on luminous efficiency of each of said picture cells.
4. A drive circuit for an EL display device which includes two electrode groups of which at least one is made of a light-permeable material and organic layers laminatedly arranged between the two electrode groups so as to provide picture cells different in area from each other acting as a luminous section, wherein a voltage is applied thereto while acting one of the two electrode groups as an anode, to thereby permit a current of a predetermined level to be flowed between the two electrode g.roups, resulting in the EL display device carrying out JLe-sired display, comprising:
a luminance correction data storage seczion having correction data which correspond to areas of said picture cells stored therein; whereby the correction data of each of said picture cells corresponding to display data are read from said luminance correction data storage section, so that a period of time during which the current is flowed between said electrode groups varlably controlled for every picture cell while rendering a current flowed to each of said picture cells constant, based on the correction data read.
5. A drive circuit as defined in claim 1, wherein said correction data depend on a luminous color of each of said picture cells.
6. A drive circuit as defined in claim 1, wherein said correction data depend on luminous efficiency of each of said picture cells.
i 3
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10130428A JPH11327506A (en) | 1998-05-13 | 1998-05-13 | Driving circuit for el display device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9910680D0 GB9910680D0 (en) | 1999-07-07 |
| GB2337354A true GB2337354A (en) | 1999-11-17 |
Family
ID=15034016
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9910680A Withdrawn GB2337354A (en) | 1998-05-13 | 1999-05-07 | Drive circuit for electroluminescent display providing uniform brightness |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPH11327506A (en) |
| KR (1) | KR19990088200A (en) |
| GB (1) | GB2337354A (en) |
| TW (1) | TW455832B (en) |
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| GB2346004A (en) * | 1999-01-20 | 2000-07-26 | Nec Corp | Light emitting display device with current control |
| GB2360870A (en) * | 2000-03-31 | 2001-10-03 | Seiko Epson Corp | Driver circuit for organic electroluminescent device |
| WO2003030136A3 (en) * | 2001-10-03 | 2003-12-04 | Koninkl Philips Electronics Nv | Device and method for varying the row scanning time to compensate the signal attenuation depending on the distance between pixel rows and column driver |
| WO2003034385A3 (en) * | 2001-10-19 | 2003-12-18 | Clare Micronix Integrated Syst | System and method for illumination timing compensation in response to row resistance |
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| EP1439518A4 (en) * | 2001-09-26 | 2007-09-05 | Sanyo Electric Co | Planar display apparatus |
| US8847997B2 (en) | 2008-03-13 | 2014-09-30 | Samsung Display Co., Ltd. | Organic light emitting display, method for driving the same, and driver therefor |
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| GB2346004B (en) * | 1999-01-20 | 2001-10-31 | Nec Corp | Display device, portable electronic device and method of controlling display d evice |
| GB2346004A (en) * | 1999-01-20 | 2000-07-26 | Nec Corp | Light emitting display device with current control |
| GB2360870A (en) * | 2000-03-31 | 2001-10-03 | Seiko Epson Corp | Driver circuit for organic electroluminescent device |
| US6943759B2 (en) | 2000-07-07 | 2005-09-13 | Seiko Epson Corporation | Circuit, driver circuit, organic electroluminescent display device electro-optical device, electronic apparatus, method of controlling the current supply to an organic electroluminescent pixel, and method for driving a circuit |
| US7079131B2 (en) | 2001-05-09 | 2006-07-18 | Clare Micronix Integrated Systems, Inc. | Apparatus for periodic element voltage sensing to control precharge |
| US7079130B2 (en) | 2001-05-09 | 2006-07-18 | Clare Micronix Integrated Systems, Inc. | Method for periodic element voltage sensing to control precharge |
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| EP1439518A4 (en) * | 2001-09-26 | 2007-09-05 | Sanyo Electric Co | Planar display apparatus |
| WO2003030136A3 (en) * | 2001-10-03 | 2003-12-04 | Koninkl Philips Electronics Nv | Device and method for varying the row scanning time to compensate the signal attenuation depending on the distance between pixel rows and column driver |
| WO2003034385A3 (en) * | 2001-10-19 | 2003-12-18 | Clare Micronix Integrated Syst | System and method for illumination timing compensation in response to row resistance |
| US7019719B2 (en) | 2001-10-19 | 2006-03-28 | Clare Micronix Integrated Systems, Inc. | Method and clamping apparatus for securing a minimum reference voltage in a video display boost regulator |
| US7019720B2 (en) | 2001-10-19 | 2006-03-28 | Clare Micronix Integrated Systems, Inc. | Adaptive control boost current method and apparatus |
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| US6995737B2 (en) | 2001-10-19 | 2006-02-07 | Clare Micronix Integrated Systems, Inc. | Method and system for adjusting precharge for consistent exposure voltage |
| US7126568B2 (en) | 2001-10-19 | 2006-10-24 | Clare Micronix Integrated Systems, Inc. | Method and system for precharging OLED/PLED displays with a precharge latency |
| US6943500B2 (en) | 2001-10-19 | 2005-09-13 | Clare Micronix Integrated Systems, Inc. | Matrix element precharge voltage adjusting apparatus and method |
| US6847171B2 (en) | 2001-12-21 | 2005-01-25 | Seiko Epson Corporation | Organic electroluminescent device compensated pixel driver circuit |
| US8847997B2 (en) | 2008-03-13 | 2014-09-30 | Samsung Display Co., Ltd. | Organic light emitting display, method for driving the same, and driver therefor |
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| CN110619819B (en) * | 2019-09-17 | 2021-07-13 | Oppo广东移动通信有限公司 | Folding screen and electronic equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11327506A (en) | 1999-11-26 |
| TW455832B (en) | 2001-09-21 |
| GB9910680D0 (en) | 1999-07-07 |
| KR19990088200A (en) | 1999-12-27 |
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| Date | Code | Title | Description |
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| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |