DISPLAY DRIVING DEVICE, DISPLAY APPARATUS, AND METHOD OF DRIVING THEM

• US 20090189924A1
• Filed: 01/29/2009
• Published: 07/30/2009
• Est. Priority Date: 01/29/2008
• Status: Abandoned Application

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: OGURA, Jun
• Application Number:
  US12/361,674
• Publication Number:
  US 20090189924A1
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/0294 Details of sampling or holding circuits arranged for use in a driver for data electrodes
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 2330/028 Generation of voltages supplied to electrode drivers in a matrix display other than LCD
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3283 in which the data driver supplies a variable data current for setting the current through, or the voltage across, the light-emitting elements

Abstract

A display driving device for driving a plurality of display pixels provided with a light emitting element which performs color display, is provided with a signal converter which is supplied a display data including a plurality of color components corresponding to the plurality of display pixels and corresponds to a predetermined number of two or more display pixels having the light emitting elements of different light emission colors from each other, based on a single conversion characteristic, different gamma correction curves corresponding to the color component, which corresponds to the light emission color of each of the light emitting elements in the predetermined number of display pixels, are generated, the color component of the display data is converted with the use of each of the gamma correction curves, and a gradation signal for driving the light emitting element in each of the display pixels is generated.

Claims

1. A display driving device for driving a plurality of display pixels provided with a light emitting element, which performs color display and has any one of a plurality of light emission colors, comprising:

a signal converter, which is supplied a display data, which corresponds to said each display pixel and includes a plurality of color components corresponding to said plurality of light emission colors and generates a gradation signal, which corresponds to the predetermined number of two or more display pixels having the light emtting element of different light emission colors from each other and is obtained by conversion of the display data,

wherein the signal converter comprises;

a gamma correction curve generator which, based on a single conversion characteristic, generates gamma correction curves different from each other which correspond to the color components corresponding to the light emission color of each of the light emitting elements in the predetermined number of display pixels and set a relation between a value of the display data and a value of the gradation signal; and

a gradation signal generator which converts the color component of the display data with the use of the generated gamma correction curve corresponding to said each color component and generates in a time series manner the gradation signal corresponding to the predetermined number of display pixels.

2. The display driving device according to claim 1, wherein a value of said each gamma correction curve, which is generated by the gamma correction curve generator and corresponds to each of the color components, is set to be such a value that a previously set color balance can be obtained, based on a luminance value of the light emitting element of said each light emission color in said plurality of display pixels with respect to the value of the display data.

3. The display driving device according to claim 1, wherein the display data is a digital signal having a plurality of bits, and the gamma correction curve generator comprises:

a gradation voltage generator, which is subjected to an application of a maximum gradation reference voltage and a minimum gradation reference voltage, generates a plurality of gradation voltages corresponding to the number of bits of the display data based on a value of the maximum gradation reference voltage and the minimum gradation reference voltage, wherein a value of said each gradation voltage serves as the single conversion characteristic; and

a gradation reference voltage switching part which switches at least any one of the maximum gradation reference voltage and the minimum gradation reference voltage in accordance with a timing of supplying each of the predetermined number of the color components in the display data and generates the gamma correction curve corresponding to each of the color components.

4. The display driving device according to claim 3, wherein the gradation voltage generator comprises a ladder resistor part, which includes a plurality of resistance elements connected in series, is in its both ends subjected to the application of the maximum gradation reference voltage and the minimum gradation reference voltage, divides a voltage between the maximum gradation reference voltage and the minimum gradation reference voltage by said each resistance element, and generates said plurality of gradation voltages, and

the gradation signal generator is subjected to a supply of the display data to select the gradation voltage corresponding to a value of the display data in said plurality of gradation voltages, and thus, to determine the selected gradation voltage as the gradation signal.

5. The display driving device according to claim 1, wherein the signal converter generates the gradation signal, corresponding to the predetermined number of display pixels, in a time series manner corresponding to the order of supplying said each color component in the display data.

6. The display driving device according to claim 1, further comprising a signal distribution circuit which distributes the gradation signal, which corresponds to the predetermined number of display pixels generated in a time series manner by the signal converter, corresponding to each of the predetermined number of display pixels.

7. The display driving device according to claim 6, further comprising a signal holding circuit which holds the gradation signals corresponding to the predetermined number of display pixels distributed by the signal distribution circuit and simultaneously outputs the gradation signals to the predetermined number of display pixels.

8. A display apparatus for performing color display, comprising:

a display panel having a plurality of data lines and a plurality of select lines perpendicular to each other and a plurality of display pixels, which are arranged near each intersection of said plurality of data lines and said plurality of select lines and have light emitting elements performing color display and having any of a plurality of light emission colors; and

a display driving device which is supplied a display data corresponding to each of light emission colors of the light emitting element in said each display pixel arrayed along the extending direction of the select line and comprising a digital signal including a plurality of color components, and generates a gradation signal based on the display data to supply the gradation signal to said plurality of display pixels through said plurality of data lines,

wherein the display driving device comprises a signal converter which is provided corresponding to a predetermined number of two or more data lines corresponding to the display pixel having the light emitting element of different light emission colors from each other in said plurality of data lines and generates the gradation signal obtained by conversion of the display data, and

the signal converter comprises;

a gamma correction curve generator which, based on a single conversion characteristic, generates gamma correction curves different from each other which correspond to color components corresponding to a light emission color of each light emitting element in the predetermined number of display pixels corresponding to the predetermined number of data lines and sets a relation between a value of the display data and a value of the gradation signal; and

a gradation signal generator which converts the color component of the display data with the use of the generated gamma correction curve corresponding to said each color component and generates in a time series manner the gradation signal corresponding to the predetermined number of the display pixels.

9. The display apparatus according to claim 8, wherein a value of said each gamma correction curve, which is generated by the gamma correction curve generator in the signal converter and corresponds to each of the color components, is set, in the display panel, to be such a value that a previously set color balance can be obtained, based on a luminance value of the light emitting element of said each light emission color in said plurality of display pixels with respect to the value of the display data.

10. The display apparatus according to claim 8, wherein the display data is a digital signal having a plurality of bits, and the gamma correction curve generator comprises:

a gradation voltage generator, which is subjected to an application of a maximum gradation reference voltage and a minimum gradation reference voltage, generates a plurality of gradation voltages corresponding to the number of bits of the display data based on a value of the maximum gradation reference voltage and the minimum gradation reference voltage, wherein a value of said each gradation voltage serves as the single conversion characteristic; and

a gradation reference voltage switching part which switches at least any one of the maximum gradation reference voltage and the minimum gradation reference voltage in accordance with a timing of supplying each of the predetermined number of the color components in the display data and generates the gamma correction curve corresponding to each of the color components.

11. The display apparatus according to claim 10, wherein the gradation voltage generator comprises a ladder resistor part, which includes a plurality of resistance elements connected in series, is in its both ends subjected to an application of the maximum gradation reference voltage and the minimum gradation reference voltage, divides a voltage between the maximum gradation reference voltage and the minimum gradation reference voltage by said each resistance element, and generates said plurality of gradation voltages, and

the gradation signal generator is subjected to a supply of the display data to select the gradation voltage corresponding to a value of the display data in said plurality of gradation voltages, and thus, to determine the selected gradation voltage as the gradation signal.

12. The display apparatus according to claim 8, wherein the signal converter generates the gradation signal, corresponding to the predetermined number of display pixels, in a time series manner corresponding to the order of supplying said each color component in the display data.

13. The display apparatus according to claim 8, wherein the display driving device comprises a signal distribution circuit which distributes the gradation signal, which corresponds to the predetermined number of display pixels generated in a time series manner by the signal converter, corresponding to each of the predetermined number of display pixels.

14. The display apparatus according to claim 13, wherein the display driving device comprises a signal holding circuit which holds the gradation signals corresponding to the predetermined number of display pixels distributed by the signal distribution circuit and simultaneously outputs the gradation signals to the predetermined number of display pixels.

15. The display apparatus according to claim 8, wherein the display driving device comprises a characteristic change compensation processor which corrects the gradation signal, generated by said each signal converter, in accordance with characteristic change of said each display pixel.

16. A method of driving a display driving device for driving a plurality of display pixels provided with a light emitting element, which performs color display and has any one of a plurality of light emission colors, comprising:

a step of converting display data, which is supplied, corresponds to said each display pixel, and includes a plurality of color components corresponding to said plurality of light emission colors, and generating a gradation signal corresponding to a predetermined number of two or more display pixels having the light emitting element of different light emission colors from each other; and

a step of supplying the generated gradation signal, corresponding to said each color component, to each of the predetermined number of display pixels,

wherein the step of generating the gradation signal comprises;

a step of, based on a single conversion characteristic, generating gamma correction curves different from each other which correspond to each of a predetermined number of color components included in the display data and setting a relation between a value of the display data and a value of the gradation signal; and

a step of converting said each color component in the display data with the use of the generated gamma correction curves corresponding to each of the color components and generating in a time series manner the gradation signal corresponding to the predetermined number of display pixels.

17. The method of driving a display driving device according to claim 16, wherein the display data is a digital signal having a plurality of bits, and

the step of generating each of the gamma correction curves comprises a step of generating a plurality of gradation voltages, which correspond to the number of bits of the display data based on a value of a maximum gradation reference voltage and a value of a minimum gradation reference voltage to be applied and have a value serving as the single conversion characteristic, switching at least any one of the maximum gradation reference voltage and the minimum gradation reference voltage in accordance with a timing of supplying each of the predetermined number of the color components in the display data, and generating the gamma correction curve corresponding to each of the color components.

18. A method of driving a display apparatus for performing color display, wherein the display apparatus has a display panel having a plurality of display pixels, which are arranged near each intersection of a plurality of data lines and a plurality of select lines perpendicular to each other and provided with a light emitting element performing color display and having any of a plurality of light emission colors, the method comprising:

a step of converting display data, which is supplied, corresponds to each of light emission colors of the light emitting element in said each display pixel arrayed in the extending direction of the select line, and comprises a digital signal including a plurality of color components, and generating a gradation signal corresponding to the predetermined number of display pixels having the light emitting element which is connected to a predetermined number of two or more data lines and has the light emitting elements of different light emission colors from each other; and

a step of supplying the generated gradation signal corresponding to said each color component to each of the predetermined number of display pixels,

wherein the step of generating the gradation signal comprises;

a step of, based on a single conversion characteristic, generating gamma correction curves different from each other which correspond to each of a predetermined number of color components included in the display data and setting a relation between a value of the display data and a value of the gradation signal; and

a step of converting said each color component in the display data with the use of the generated gamma correction curves corresponding to each of the color components and generating in a time series manner the gradation signal corresponding to the predetermined number of display pixels.

19. The method of driving a display apparatus according to claim 18, wherein the display data is a digital signal having a plurality of bits, and

the step of generating each of the gamma correction curves comprises a step of generating a plurality of gradation voltages, which correspond to the number of bits of the display data based on a value of a maximum gradation reference voltage and a value of a minimum gradation reference voltage to be applied and have a value serving as the single conversion characteristic, switching at least any one of the maximum gradation reference voltage and the minimum gradation reference voltage in accordance with a timing of supplying each of the predetermined number of the color components in the display data, and generating the gamma correction curve corresponding to each of the color components.