Display apparatus and method of driving the same

• US 10,311,812 B2
• Filed: 03/01/2017
• Issued: 06/04/2019
• 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
• Primary Examiner(s): Edwards, Mark
• Application Number:
  US15/446,137
• Publication Number:
  US 20170294169A1
• Time in Patent Office: 825 Days
• Field of Search: 345209
• 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 first moving image mode or a second moving image mode when the input image data are moving image data and to output film image data at a number of frames per second of a middle level lower than the high level during the first moving image mode, the first moving image mode corresponding to a film mode and the second moving image mode corresponding to a normal 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,

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 correspond to update image data, and

other frame image data among the frame image data equal to each other of each of the frame image data groups correspond 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,

wherein the film image data is first copy image data right after the update image data.

2. The display apparatus as claimed in claim 1, 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.

3. The display apparatus as claimed in claim 2, 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.

4. The display apparatus as claimed in claim 2, 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.

5. The display apparatus as claimed in claim 1, 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.

6. The display apparatus as claimed in claim 1, 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.

7. The display apparatus as claimed in claim 6, 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.

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

9. The display apparatus as claimed in claim 6, 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.

10. The display apparatus as claimed in claim 2, wherein the image converter is to be operated in a stop mode when the input image data are still image data.

11. The display apparatus as claimed in claim 10, 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.

12. The display apparatus as claimed in claim 11, 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.

13. 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.

14. The display apparatus as claimed in claim 1, wherein the frequency of the middle level during the film mode is lower than a frequency during the normal mode.

15. The display apparatus as claimed in claim 1, wherein the data driver is to operate based on a first standby power in the film mode and a second standby power in the normal mode, and wherein the first standby power is less than the second standby power.

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

the data driver is to operate based on continuously supplied power during the normal mode, and

the data driver is to operate based on power that is not continuously supplied during the film mode.