KR100600396B1 - Light emitting display and driving method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting display device and a method of driving the same, which can prevent a color shift and make a white balance uniform.

The light emitting display device according to the present invention includes an image display portion for displaying an image, a data driver for supplying a gray scale voltage corresponding to a data signal using a gamma voltage of three colors, to the image display portion, and three colors displayed on the image display portion. And a detection unit for extracting detection signals of three colors corresponding to the amount of light of each image, and a control unit for adjusting each of the three gamma voltages according to the detection signals of the three colors from the detection unit.

By this configuration, the present invention detects the amount of light of each of the red, green, and blue images displayed on the image display unit, and automatically adjusts the red, green, and blue reference gamma voltages individually, thereby shifting color shifts due to the lifespan and characteristics of the light emitting device. The phenomenon can be prevented, and the white balance of red, green, and blue generated due to the characteristic deviation of the light emitting device can be made uniform.

Description

LIGHT EMITTING DISPLAY AND DRIVING METHOD THEREOF             

1 illustrates a general light emitting display device.

2 is a diagram illustrating a light emitting display device according to an exemplary embodiment of the present invention.

FIG. 3 is a diagram illustrating an arrangement structure of the light amount detector illustrated in FIG. 2.

4 is a diagram illustrating the control unit shown in FIG. 2.

FIG. 5 is a diagram illustrating a gamma voltage supply unit illustrated in FIG. 2.

6 is a flowchart illustrating a method of driving a light emitting display device according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

20, 120: image display unit 21, 121: pixel

30, 130: scan driver 40, 140: data driver

50, 150: control unit 60, 160: gamma voltage supply unit

110: substrate 152: look up table

154: comparison unit 156: reference gamma voltage generation unit

162: R gamma voltage generator 164: G gamma voltage generator

166: B gamma voltage generator 170: light amount detector

172, 174, 176, 178: light sensor

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a light emitting display device, and more particularly, to a light emitting display device and a driving method thereof, which can prevent a color shift and make a white balance uniform.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes. The flat panel display includes a liquid crystal display, a field emission display, a plasma display panel, a light emitting display, and the like.

Among the flat panel displays, a light emitting display device is a self-light emitting device that emits a fluorescent material by recombination of electrons and holes, and includes an inorganic light emitting display device including an inorganic light emitting layer and an organic light emitting layer according to materials and structures. It is roughly divided into. Such a light emitting display device has an advantage of having a fast response speed, such as a cathode ray tube, compared to a passive light emitting device requiring a separate light source like a liquid crystal display device.

1 is a diagram illustrating the light emitting display device illustrated in FIG. 1.

Referring to FIG. 1, a general light emitting display device includes an image display unit 20, a scan driver 30, a data driver 40, a controller 50, and a gamma voltage supply unit 160.

The image display unit 20 includes a plurality of pixels 21 formed in a region defined by the plurality of scan lines S1 to Sn and the plurality of data lines D1 to Dm. Each pixel 21 includes a light emitting element that emits light by a current corresponding to a data signal supplied to the data lines D1 to Dm. In this case, the light emitting device may be an organic light emitting device. The organic light emitting diode includes an emission layer (EML), an electron transport layer (ETL), and a hole transport layer (HTL) of an organic material formed between the anode electrode and the cathode electrode. The organic light emitting diode may further include an electron injection layer (EIL) and a hole injection layer (HIL). In the organic light emitting diode, when a voltage is applied between the anode electrode and the cathode electrode, electrons generated from the cathode electrode move toward the light emitting layer through the electron injection layer and the electron transport layer, and holes generated from the anode electrode are transferred to the hole injection layer and the hole transport layer. It moves to the light emitting layer through. Accordingly, in the light emitting layer, light is generated by collision between electrons and holes supplied from the electron transporting layer and the hole transporting layer and recombination.

As such, the image display unit 20 causes the light emitting elements of the selected pixels 21 to emit light in accordance with the data signals supplied to the data lines D1 to Dm when the scanning lines S1 to Sn are sequentially selected to display an image. do.

The controller 50 arranges the data signal Data supplied from the outside to be suitable for driving the image display unit 20 and supplies the data signal 40 to the data driver 40. In addition, the controller 50 controls the driving of the scan driver 30 and the data driver 40.

The scan driver 30 generates scan signals for sequentially driving the scan lines S1 to Sn in response to the scan control signals SCS supplied from the controller 50, that is, the start pulse and the clock signal. It is sequentially supplied to (S1 to Sn).

The gamma voltage supply unit 60 generates a plurality of red gamma voltages GAM_R, a plurality of green gamma voltages GAM_G, and a plurality of blue gamma voltages GAM_B and supplies them to the data driver 40.

The data driver 40 selects the gamma voltage supplied from the gamma voltage supply unit 60 according to the data signal Data from the controller 50 in response to the data control signal DCS supplied from the controller 50, and then the data. Supply to line (D). In detail, in the case of the red data signal, the data driver 40 selects one of the plurality of red gamma voltages GAM_R corresponding to the red data signal Data supplied from the controller 50, and thus the data line D. To feed. In addition, in the case of the green data signal, the data driver 40 selects one of the plurality of green gamma voltages GAM_G corresponding to the green data signal Data and supplies the selected data line D to the corresponding data line D. In the case of the blue data signal, the data driver 40 selects one of the plurality of blue gamma voltages GAM_B corresponding to the blue data signal Data and supplies the selected data to the data line D.

Such a general light emitting display device has a color shift phenomenon in which a predetermined color is expressed in a white state such as Redish or Greenish due to a change in lifespan and characteristics of a light emitting device. There is a problem that occurs. In addition, a general light emitting display device has a problem that the white balance caused by the characteristic deviation of the light emitting device is uneven.

Accordingly, an object of the present invention is to provide a light emitting display device and a method of driving the same, which can prevent color shift phenomenon and make white balance uniform.

As a technical means for achieving the above object, the first aspect of the present invention provides an image display unit for displaying an image, a data driver for supplying a gray scale voltage corresponding to a data signal to the image display unit using a gamma voltage of three colors; A detection unit for extracting a detection signal of three colors corresponding to the amount of light of each of the three color images displayed on the image display unit, and a control unit for adjusting each of the three gamma voltages according to the detection signal of the three colors from the detection unit. Provided is a light emitting display device.

Preferably, the controller compares the lookup table in which the reference light quantity values corresponding to the reference light amounts of the three color images are stored, and the reference light quantity value and the detection signals of the three colors, respectively, to compare the reference gamma voltage setting signal of the three colors. And a reference gamma voltage generator for generating each of the three reference gamma voltages according to the three reference gamma voltage setting signals. In addition, the light emitting display device supplies a plurality of first color gamma voltages, a plurality of second color gamma voltages, and a plurality of third color gamma voltages to the data driver by using each of the three reference gamma voltages. It further has a supply part. The detection unit is a plurality of optical sensors arranged to be adjacent to the image display unit to generate detection signals of the three colors that are different according to the amount of light of each of the three color images.

A method of driving a light emitting display device according to an embodiment of the present invention includes the steps of (a) displaying three-color images on an image display unit stepwise, and (b) corresponding to the amount of light of each of the three-color images displayed on the image display unit. Extracting three detection signals step by step, (c) adjusting each of the three gamma voltages according to the three detection signals, and (d) using the three gamma voltages. A method of driving a light emitting display device includes supplying a gray voltage corresponding to a signal to the image display unit.

Preferably, the method of driving the light emitting display device further includes extracting and storing a reference light amount value corresponding to the light amount of each of the at least three color images. In the step (c), the reference light amount value is compared with each of the detection signals of the three colors to generate three reference gamma voltage setting signals, and three colors according to the three reference gamma voltage setting signals. Generating each of the reference gamma voltages and generating each of the plurality of third color gamma voltages using each of the three reference gamma voltages.

Hereinafter, with reference to the accompanying drawings 2 to 6 the most preferred embodiment that can be easily carried out by those of ordinary skill in the art as follows.

2 is a diagram illustrating a light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the light emitting display device according to an exemplary embodiment of the present invention includes an image display unit 120, a scan driver 130, a data driver 140, a controller 150, a gamma voltage supply unit 160, and a light amount detector. 170 is provided.

The image display unit 120 includes a plurality of pixels 121 formed in a region defined by the plurality of scan lines S1 to Sn and the plurality of data lines D1 to Dm. Each pixel 121 includes a light emitting device that emits light by a current corresponding to a data signal supplied to the data lines D1 to Dm. In this case, the light emitting device may be an organic light emitting device. The organic light emitting diode includes an emission layer (EML), an electron transport layer (ETL), and a hole transport layer (HTL) of an organic material formed between the anode electrode and the cathode electrode. The organic light emitting diode may further include an electron injection layer (EIL) and a hole injection layer (HIL). In the organic light emitting diode, when a voltage is applied between the anode electrode and the cathode electrode, electrons generated from the cathode electrode move toward the light emitting layer through the electron injection layer and the electron transport layer, and holes generated from the anode electrode are transferred to the hole injection layer and the hole transport layer. It moves to the light emitting layer through. Accordingly, in the light emitting layer, light is generated when the electrons and holes supplied from the electron transport layer and the hole transport layer collide and recombine.

As such, the image display unit 120 emits light from the light emitting elements of the selected pixels 121 according to data signals supplied to the data lines D1 to Dm when the scanning lines S1 to Sn are sequentially selected to display an image. do.

The light amount detection unit 170 corresponds to the red, green, and blue light amounts for each of the red, green, and blue images displayed on the image display unit 120 using a test pattern during initial driving of the light emitting display device or in a test mode. The green and blue light quantity signals Lr, Lg, and Lb are extracted and supplied to the controller 150.

The controller 150 arranges the data signal Data supplied from the outside to be suitable for driving the image display unit 120 and supplies the data signal to the data driver 140. In addition, the controller 150 controls the driving of the scan driver 130 and the data driver 140. The controller 150 adjusts the red, green, and blue white balances according to the red, green, and blue light amount signals Lr, Lg, and Lb supplied from the light amount detector 170. The reference gamma voltages VR, VG, and VB are compensated for and supplied to the gamma voltage supply unit 160.

The scan driver 130 generates scan signals for sequentially driving the scan lines S1 to Sn in response to the scan control signals SCS supplied from the controller 150, that is, the start pulse and the clock signal. It is sequentially supplied to (S1 to Sn).

The gamma voltage supply unit 160 uses the compensated red, green, and blue reference gamma voltages VR, VG, and VB supplied from the controller 150, respectively, to provide a plurality of red gamma voltages GAM_R and a plurality of green gamma. The voltage GAM_G and the plurality of blue gamma voltages GAM_B are generated and supplied to the data driver 140.

The data driver 140 selects the gamma voltage supplied from the gamma voltage supply unit 160 according to the data signal Data from the controller 150 in response to the data control signal DCS supplied from the controller 150, thereby providing data. Supply to line (D). In detail, in the case of the red data signal, the data driver 140 selects any one of the plurality of red gamma voltages GAM_R corresponding to the red data signal Data supplied from the controller 150, to thereby correspond to the corresponding data line D. To feed. In addition, in the case of the green data signal, the data driver 140 selects one of the plurality of green gamma voltages GAM_G corresponding to the green data signal Data and supplies the selected data line D to the corresponding data line D. In the case of the blue data signal, the data driver 140 selects one of the plurality of blue gamma voltages GAM_B corresponding to the blue data signal Data and supplies the selected data to the data line D.

3 is a diagram illustrating an arrangement structure of the light amount detector 170 illustrated in FIG. 1.

3 and 2, the light amount detector 170 may be a plurality of light sensors 172, 174, 176, and 178 to be adjacent to the image display unit 120 provided on the substrate 110. Each of the plurality of light sensors 172, 174, 176, and 178 outputs different output values according to the amounts of red, green, and blue light.

The first optical sensor 172 of the plurality of optical sensors 172, 174, 176, and 178 is disposed on the substrate 110 adjacent to the upper left of the image display unit 120, and the second optical sensor 174 is an image. The third optical sensor 176 is disposed on the substrate 110 adjacent to the upper right side of the display unit 120, and the third optical sensor 176 is disposed on the substrate 110 adjacent to the lower left side of the image display unit 120. The 178 may be disposed on the substrate 110 adjacent to the lower right side of the image display unit 120.

Each of the plurality of light sensors 172, 174, 176, and 178 extracts an amount of red light corresponding to a red image displayed on the image display unit 120 by using a test pattern during initial driving of the light emitting display device or in a test mode. The red light quantity signal Lr is supplied to the controller 150. After extracting the red light amount, each of the plurality of light sensors 172, 174, 176, and 178 extracts the green light amount according to the green image displayed on the image display unit 120, and outputs the green light signal Lg corresponding thereto. Supply to the control unit 150. After extracting the green light amount, each of the plurality of light sensors 172, 174, 176, and 178 extracts the blue light amount corresponding to the blue image displayed on the image display unit 120, and corresponds to the blue light amount signal Lb corresponding thereto. ) Is supplied to the controller 150. At this time, the order of extraction of the red light amount, the green light amount and the blue light amount may be changed.

4 is a block diagram illustrating a part of the controller 150 illustrated in FIG. 2.

4, the controller 150 includes a lookup table 152, a comparator 154, and a reference gamma voltage generator 156.

The lookup table 152 stores the red, green, and blue reference light signal values Rr, Rg, and Rb corresponding to the reference red light, the reference green light, and the reference blue light. At this time, the red, green, and blue reference light quantity signal values Rr, Rg, and Rb are extracted using the red, green, and blue images using the light emitting devices in the normal state.

The comparator 154 includes three comparators. The first comparator compares the red light quantity signal Lr supplied from the light quantity detector 170 with the red reference light quantity signal value Rr supplied from the lookup table 152, and according to the comparison result, the red reference gamma The voltage setting signal Cr is generated and supplied to the reference gamma voltage generator 156. The second comparator compares the green light quantity signal Lg supplied from the light quantity detector 170 with the green reference light quantity signal value Rg supplied from the lookup table 152, and according to the comparison result, the green reference gamma The voltage setting signal Cg is generated and supplied to the reference gamma voltage generator 156. The third comparator compares the blue light amount signal Lb supplied from the light amount detection unit 170 with the blue reference light amount signal value Rb supplied from the lookup table 152 and, according to the comparison result, the blue reference gamma. The voltage setting signal Cb is generated and supplied to the reference gamma voltage generator 156. As a result, the comparator 154 uses the first to third comparators to generate the red, green, and blue reference gamma voltage setting signals Cr, Cg, and Cb for uniformizing the white balance of red, green, and blue. Is generated and supplied to the reference gamma voltage generator 156.

The reference gamma voltage generator 156 may generate the red, green, and blue reference gamma voltages VR and VG according to the red, green, and blue reference gamma voltage setting signals Cr, Cg, and Cb supplied from the comparator 154. , VB) is set and supplied to the gamma voltage supply unit 160. As a result, the reference gamma voltage generator 156 generates the gamma voltage supply units 160 by generating the reference gamma voltages VR, VG, and VB of the red, green, and blue colors to uniformly balance the red, green, and blue white balances. Supplies).

5 is a diagram illustrating the gamma voltage generator 160 shown in FIG. 1.

5, the gamma voltage generator 160 includes a red gamma voltage generator 162, a green gamma voltage generator 164, and a blue gamma voltage generator 166.

The red gamma voltage generator 162 generates a plurality of red gamma voltages GMA_R having different levels by using the red reference gamma voltage VR supplied from the controller 150 and supplies them to the data driver 140. do.

The green gamma voltage generator 164 generates a plurality of green gamma voltages GMA_G having different levels by using the green reference gamma voltage VG supplied from the controller 150, and supplies them to the data driver 140. do.

The blue gamma voltage generator 166 generates a plurality of blue gamma voltages GMA_B having different levels by using the blue reference gamma voltage VB supplied from the controller 150 and supplies them to the data driver 140. do.

As described above, the light emitting display device according to the embodiment of the present invention uses red, green, and blue images displayed on the image display unit 120 by using a test pattern during initial driving (setup) of the image display unit 120 or in a test mode. Each of the red, green, and blue light amount signals Lr, Lg, and Lb is extracted, and the red, green, and blue reference gamma voltages are extracted using the extracted red, green, and blue light amount signals, Lr, Lg, and Lb. VR, VG, VB). Accordingly, the light emitting display device according to the embodiment of the present invention uniformly adjusts the white balance of red, green, and blue by using the set red, green, and blue reference gamma voltages VR, VG, and VB.

As a result, the light emitting display device according to an exemplary embodiment of the present invention automatically adjusts the red, green, and blue reference gamma voltages VR, VG, and VB according to the output value of the optical sensor, thereby changing the lifespan and characteristics of the light emitting device. Due to this, it prevents a color shift phenomenon in which a predetermined color is expressed in a white state, such as Redish or Greenish, and red, green, and White balance of blue can be made uniform.

Meanwhile, the scan driver 130 and / or the data driver 140 may be electrically connected to a substrate including the image display unit 120, or a tape carrier package that is electrically attached to the substrate. ) May be mounted in the form of a chip. On the other hand, the scan driver 130 and / or the data driver 140 may be mounted in the form of a chip or the like on a flexible printed circuit or a film that is bonded and electrically connected to the substrate. It may also be referred to as a Chip On Flexible Board (Chip On Film) method. On the other hand, the scan driver 130 and / or the data driver 140 and / or the gamma voltage generator 160 may be directly mounted on the substrate, which is called a chip on glass (COG) method. . It may also be replaced with a driving circuit formed on the substrate in the same layers as the signal line, the data line D and the thin film transistor.

6 is a flowchart illustrating a method of driving a light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 6 in conjunction with FIG. 2, a method of driving a light emitting display device according to an exemplary embodiment of the present invention will be described below. Here, the driving method of the light emitting display device according to the embodiment of the present invention may be applied during the initial driving of the light emitting display device (re-driven after the setup or the end of driving) or in the test mode.

First, a red image is displayed on the image display unit 120. First step (S1)

Following the first step S1, the red light amount signal Lr corresponding to the red light amount emitted from the light amount detection unit 170, that is, the image display unit 120 displaying the red image is extracted using the plurality of light sensors. do. Second step (S2)

Following the second step S2, a green image is displayed on the image display unit 120. Third step (S3)

After the third step S3, the green light amount signal Lg corresponding to the amount of green light emitted from the image display unit 120 displaying the green image is extracted using the plurality of light sensors. Fourth step (S4)

Subsequent to the fourth step S4, a blue image is displayed on the image display unit 120. FIG. 5th step (S5)

Subsequently to the fifth step S5, a blue light amount signal Lb corresponding to the amount of blue light emitted from the image display unit 120 displaying a blue image is extracted using a plurality of light sensors. Sixth step (S6)

Following the sixth step S6, the red, green, and blue light amount signals Lr, Lg, Lb and the reference red, green, and blue light amount signals extracted in the second, fourth, and sixth steps S2, S4, and S6. The reference gamma voltage setting signal is generated by comparing the values. Then, the reference gamma voltages VR, VG, and VB of red, green, and blue are set according to the reference gamma voltage setting signal. Seventh Step (S7)

Then, the gamma voltage supply unit 160 generates a plurality of red, green, and blue gamma voltages GMA_R, generated by the red, green, and blue reference gamma voltages VR, VG, and VB set in the seventh step S7. GMA_G and GMA_B are supplied to the data driver 140. Accordingly, the data driver 140 corresponds to the gradation voltages corresponding to the plurality of red, green, and blue gamma voltages GMA_R, GMA_G, and GMA_B supplied from the gamma voltage supply unit 160 according to the data signal supplied from the controller 150. Is selected and supplied to the data line D of the image display unit 120.

As a result, the method of driving the light emitting display device according to an exemplary embodiment of the present invention automatically adjusts the red, green, and blue reference gamma voltages VR, VG, and VB in accordance with the output value of the optical sensor. Due to the characteristic change, a color shift phenomenon such as a predetermined color is expressed in a white state, such as Redish or Greenish, is prevented, and a red color generated due to the characteristic deviation of the light emitting device White balance of green, blue, and blue can be made uniform.

The above detailed description and drawings are merely exemplary of the present invention, which are used only for the purpose of illustrating the present invention and are not intended to limit the scope of the present invention as defined in the claims or the claims. Accordingly, those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. As a result, the technical protection scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

As described above, the light emitting display device and the driving method thereof according to the embodiment of the present invention detect the amount of light of each of the red, green, and blue images displayed on the image display unit, and automatically detect the red, green, and blue reference gamma voltages individually. By adjusting, it is possible to prevent color shift due to a change in lifespan and characteristics of the light emitting device, and to equalize the white balance of red, green, and blue generated due to the characteristic deviation of the light emitting device.

Claims (7)

An image display unit for displaying an image, A data driver for supplying a gray scale voltage corresponding to the data signal to the image display unit using three gamma voltages; A detection unit for extracting a detection signal of three colors corresponding to the amount of light of each of the three color images displayed on the image display unit; And a control unit for adjusting each of the three color gamma voltages according to the detection signal of the three colors from the detection unit. The method of claim 1, The control unit, A look-up table storing a reference light quantity value corresponding to a reference light quantity of each of the three color images; A comparator for comparing the reference light quantity value with each of the detection signals of the three colors and generating a reference gamma voltage setting signal of three colors; And a reference gamma voltage generator configured to generate each of the three reference gamma voltages according to the three reference gamma voltage setting signals. The method of claim 2, A light emitting display further includes a gamma voltage supply unit configured to supply a plurality of first color gamma voltages, a plurality of second color gamma voltages, and a plurality of third color gamma voltages to the data driver using each of the three reference gamma voltages. Device. The method of claim 1, And the detection unit is a plurality of optical sensors arranged to be adjacent to the image display unit to generate detection signals of the three colors that are different according to the amount of light of each of the three color images. (a) displaying an image of three colors step by step on an image display unit; (b) stepwise extracting detection signals of three colors corresponding to the amount of light of each of the three color images displayed on the image display unit; (c) adjusting the gamma voltages of the three colors according to the detection signals of the three colors; and (d) supplying a gray scale voltage corresponding to a data signal to the image display unit using the three gamma voltages. The method of claim 5, wherein And extracting and storing a reference light amount value corresponding to the light amount of each of the at least three color images. The method of claim 6, In step (c), Generating a reference gamma voltage setting signal of three colors by comparing the reference light quantity value with each of the detection signals of the three colors; Generating each of the three reference gamma voltages according to the three reference gamma voltage setting signals; And generating each of the plurality of third color gamma voltages using each of the three reference gamma voltages.

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