DISPLAY APPARATUS AND METHOD OF DRIVING THE SAME

• US 20170294169A1
• Filed: 03/01/2017
• Published: 10/12/2017
• Est. Priority Date: 04/08/2016
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: LEE, Kyoungwon, OH, Kwan-young, SEO, Jimyoung, YOU, Bonghyun, CHO, Junghwan, HAN, Sangsu
• Granted Patent: US 10,311,812 B2
• Time in Patent Office: Days
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2330/023 using energy recovery or conservation
• CPC Class Codes: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3677 suitable for active matrices only
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

A display apparatus includes a display panel, a timing controller, a data driver, and a gate driver. The timing controller receives image data at a number of frames per second of a first level and generates a gate control signal and a data control signal. The timing controller includes an image converter that operates in film mode or normal mode when the input image data are moving image data, and that outputs film image data at a number of frames per second of second level lower than the first level during the film mode. The data driver applies a data voltage corresponding to the film image data to the display panel based on the data control signal. The gate driver applies a gate voltage to the display panel based on the gate control signal. The display panel operates at a frequency of the second level during the film mode.

Claims

1. A display apparatus, comprising:

a display panel to display images;

a timing controller to receive input image data at a number of frames per second of a high level and to generate a gate control signal and a data control signal, the timing controller including an image converter to operate in a film mode or a normal mode when the input image data are moving image data and to output film image data at a number of frames per second of middle level lower than the high level during the film mode;

a data driver to apply a data voltage corresponding to the film image data to the display panel based on the data control signal; and

a gate driver to apply a gate voltage to the display panel based on the gate control signal, the display panel to be operated at a frequency of the middle level during the film mode.

2. The display apparatus as claimed in claim 1, wherein the input image data include:

frame image data groups, each of the frame image data groups including a plurality of frame image data equal to each other, wherein;

first frame image data among the frame image data equal to each other of each of the frame image data groups corresponding to update image data,

other frame image data among the frame image data equal each other of each of the frame image data groups corresponding to copy image data, and

the timing controller is to select one of the film mode or the normal mode based on an interval between frames in which the update image data are input.

3. The display apparatus as claimed in claim 2, wherein the image converter includes:

a copy image detector to analyze the input image data in a unit of a frame to determine whether the input image data are the update image data or the copy image data and to output an image flag signal;

a mode selector to receive the image flag signal, output a film mode signal when the update image data are input every frame equal to or greater than K, and output a normal mode signal when the update image are input every frame less than K, wherein K is a natural number;

a film mode controller to receive the film mode signal and to output the film image data; and

a normal mode controller to receive the normal mode signal to output normal image data.

4. The display apparatus as claimed in claim 3, wherein:

the normal mode controller is to output the normal image data at a number of frames per second of the high level, and

the display panel is to be operated at a frequency having the high level during the normal mode.

5. The display apparatus as claimed in claim 3, wherein the copy image detector is to compare a value derived from four arithmetical operations of one frame image data of two frame image data among the input image data to a value derived from four arithmetical operations of the other frame image data of the two frame image data among the input image data, to determine whether two consecutive frame image data are equal to each other.

6. The display apparatus as claimed in claim 3, wherein the film image data include first copy image data right after the update image data.

7. The display apparatus as claimed in claim 6, wherein the display panel is to be charged with a data voltage corresponding to one first copy image data during a plurality of frames set based on a frequency having the high level.

8. The display apparatus as claimed in claim 6, wherein:

the display panel is a liquid crystal display panel, and

the film mode controller includes;

a film image data generator to receive the film mode signal and to output the film image data;

a polarity compensator to receive the film image data to output a first polarity signal to the data driver; and

a power controller to receive the film image data to output a first power control signal to the data driver.

9. The display apparatus as claimed in claim 8, wherein the data driver is:

to invert a polarity of the data voltage whenever the data voltage corresponding to the frame image data in the film image data is output based on the first polarity signal during the film mode, and

is not to invert the polarity when an absolute value of a cumulative polarity is equal to or greater than a predetermined value and the cumulative polarity increases due to the polarity inversion.

10. The display apparatus as claimed in claim 8, wherein the data driver is:

to invert a polarity of the data voltage whenever the data voltage corresponding to the frame image data in the film image data is output based on the first polarity signal during the film mode, and

when two or more copy image data in one frame image data group among the frame image data groups, input when an absolute value of a cumulative polarity is equal to or greater than a predetermined value, are consecutive and cumulative polarity increases due to a polarity inversion when the data voltage corresponding to the first copy image data is output, the film image data includes copy image data right after the first copy image data.

11. The display apparatus as claimed in claim 8, wherein:

the first power control signal is in a first state during output periods of the film image data,

the power control signal is in a second state during blank periods between the output periods of the film image data,

the data driver is to receive power during the first state of the first power control signal, and

the data driver is not to receive power during the second state of the first power control signal.

12. The display apparatus as claimed in claim 3, wherein the image converter is to be operated in a stop mode when the input image data are still image data.

13. The display apparatus as claimed in claim 12, wherein:

the mode selector is to output the film mode signal when the update image data are input every frame in a range between K and N inclusive,

the mode selector is to output a stop mode signal when the update image data are not input during M or more frames, where N is a natural number equal to or greater than the K and M is a natural number greater than the N.

14. The display apparatus as claimed in claim 13, wherein:

the image converter includes a stop mode controller to receive the stop mode signal and to output the still image data at a number of frames per second of a low level less than the middle level, and

the display panel is to be operated at a frequency having the low level during the stop mode.

15. The display apparatus as claimed in claim 1, wherein:

the display panel includes a pixel connected to a gate line and a data line, the pixel including a thin film transistor connected to the gate line and the data line with an oxide semiconductor as a channel layer thereof, a pixel electrode connected to the thin film transistor, and a common electrode facing the pixel electrode.

16. A display apparatus, comprising:

a display panel to display images;

a timing controller to receive input image data at a number of frames per second of high level lower than about 60 fps and to generate a gate control signal and a data control signal, the timing controller including an image converter to be operated in a film mode or a normal mode when the input image data are moving image data and to output film image data at a number of frames per second of the high level during the film mode;

a data driver to apply a data voltage corresponding to the film image data to the display panel based on the data control signal; and

a gate driver to apply a gate voltage to the display panel based on the gate control signal, the display panel to be operated at a frequency of the high level during the film mode.

17. The display apparatus as claimed in claim 16, wherein:

the input image data include update image data different from each other and blank data between the update image data, and

the timing controller is to select one of the film mode or the normal mode based on a number of the update image data input during a specific time period.

18. The display apparatus as claimed in claim 17, wherein the image converter includes:

a mode selector to receive the input image data, output a film mode signal when the number of the update image data input during the specific time period is in a range between F and G inclusive, output a normal mode signal when the number of the update image data input during the specific time period exceeds G, and output a stop mode signal when the number of the update image data input during the specific time period is less than F, where F is a natural number and G is a natural number equal to or greater than F;

a film mode controller to receive the film mode signal to output the film image data;

a normal mode controller to receive the normal mode signal to output the normal image data; and

a stop mode controller to receive the stop mode signal to output still image data.

19. The display apparatus as claimed in claim 18, wherein:

the normal mode controller is to output the normal image data at a number of frames per second of a middle level greater than the high level,

the stop mode controller is to output stop image data at a number of frames per second of low level less than the middle level,

the display panel is to be operated at a frequency of the middle level during the normal mode and is to be operated at a frequency of the low level during the stop mode.

20. The display apparatus as claimed in claim 19, wherein:

the film image data include the update image data, and

the display panel is to be charged with the data voltage corresponding to one update image data during a plurality of frames set based on the frequency of the middle level.

21. A method of driving a display apparatus, the method comprising:

inputting image data at a number of frames per second of a high level;

analyzing the input image data in a unit of frame to determine whether the input image data are update image data or copy image data; and

operating a display panel in a film mode in which the display panel is to be operated at a frequency having a middle level lower than the high level when the update image data of the input image data satisfy a film mode condition, in which the update image data of the input image data are input every frame equal to or greater than K.

22. The method as claimed in claim 21, wherein operating the display panel in the film mode includes:

outputting film image data including first copy image data right after the update image data at the number of frames of the middle level;

controlling a polarity inversion to invert a polarity of a data voltage corresponding to the update image data whenever the data voltage corresponding to the update image data is output and not to invert the polarity of the data voltage when an absolute value of a cumulative polarity is greater than a predetermined value and the cumulative polarity increases due to the polarity inversion; and

controlling power of a data driver so that power is not provided to the data driver during blank periods between output periods of the film image data.

23. The method as claimed in claim 21, further comprising:

operating the display panel in a normal mode in which the display panel is operated at a frequency having the middle level when the film mode condition is not satisfied.

24. The method as claimed in claim 21, further comprising:

operating the display panel in a stop mode in which the display panel is operated at a frequency having a low level lower than the middle level when the film mode condition is not satisfied and a stop mode condition in which the update image data of the input image data are not input during M or more frames is satisfied,

wherein the film mode condition is satisfied when the update image data of the input image data are input every frame in a range between K and N inclusive, where N is a natural number equal to or greater than K and M is a natural number greater than N.

25. The method as claimed in claim 24, further comprising:

operating the display panel in a normal mode in which the display panel is operated at a frequency having a middle level when the stop mode condition is not satisfied.

26. A method of driving a display apparatus, the method comprising:

inputting image data including update image data and blank image data to a timing controller at a number of frames per second of a middle level lower than about 60 fps; and

operating a display panel in a film mode in which the display panel is operated at a frequency having the middle level when a number of the update image data of the image data input during a specific time period satisfies a film mode condition in which the number of the update image data is in a range of between F and G inclusive, where F is a natural number and G is a natural number equal to or greater than F.

27. The method as claimed in claim 26, further comprising:

operating the display panel in a stop mode in which the display panel is operated at a frequency having a low level lower than the middle level when the film mode condition is not satisfied and a stop mode condition in which the number of the update image data of the input image data is less than F is satisfied; and

operating the display panel in a normal mode when the stop mode condition is not satisfied so that the display panel is operated at a frequency having a high level higher than the middle level.