Organic light emitting diode display device and method of driving the same

• US 9,691,321 B2
• Filed: 12/30/2014
• Issued: 06/27/2017
• Est. Priority Date: 12/31/2013
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Eom, Eun-Cheol
• Primary Examiner(s): Nguyen, Jimmy H
• Application Number:
  US14/586,498
• Publication Number:
  US 20150187262A1
• Time in Patent Office: 910 Days
• Field of Search: 345690, 345 76- 83
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• 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 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2320/0686 with two or more screen areas displaying information with different brightness or colours
• CPC Class Codes: G09G 2330/022 in absence of operation, e.g. no data being entered during a predetermined time
• CPC Class Codes: G09G 2330/028 Generation of voltages supplied to electrode drivers in a matrix display other than LCD
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: G09G 3/3275 Details of drivers for data electrodes
• CPC Class Codes: G09G 5/14 Display of multiple viewports

Abstract

An organic light emitting diode (OLED) display device using split window technology and a method of controlling the OLED display device. The OLED display device includes a system configured to split a display panel into a plurality of regions and operate in separate modes including a split window mode for transmitting split image data corresponding to respective regions to display different images on the respective regions and a normal mode for transmitting normal image data to display one image on the entire display panel, and a panel driving circuit configured to drive the display panel according to the split image data or the normal image data provided from the system.

Claims

1. An organic light emitting diode (OLED) display device comprising:

a system configured to;

split a display panel into a plurality of regions and operate in separate modes including a split window mode for transmitting split image data corresponding to respective regions to display different images on the respective regions and a normal mode for transmitting normal image data to display one image on the entire display panel; and

a panel driving circuit configured to;

drive the display panel according to the split image data or the normal image data provided from the system,

vary a plurality of gamma voltage levels to separately control luminance or color characteristics of each of the plurality of regions during a blank period between a period for scanning a first window region and a period for scanning a second window region according to a result obtained by analyzing the split image data in the split window mode, and

control a specific region in a lowest luminance state until a user input signal is generated when the user input signal is not present during a predetermined period of time or more in the specific portion of the plurality of regions,

wherein the panel driving circuit includes a gamma voltage generating circuit to vary the plurality of gamma voltage levels to reduce power consumption.

2. The OLED display device according to claim 1, wherein the panel driving circuit includes:

a gate driver configured to sequentially supply scan pulses to gate lines of the display panel and sequentially scan the plurality of regions;

a data driver configured to apply a data voltage to data lines of the display panel;

a timing controller configured to;

align the split image data or the normal image data provided from the system and supply the split image data or the normal image data to the data driver,

generate a gate control signal for control of the gate driver and a data control signal for control of the data driver using an external input synchronization signal, and

output a luminance control signal according to a result obtained by analyzing the split image data or the normal image data; and

the gamma voltage generating circuit configured to generate a reference gamma voltage having a level, vary the level of the reference gamma voltage in response to the luminance control signal, and supply the level-varied reference gamma voltage to the data driver,

wherein, in the split window mode, the timing controller varies the luminance control signal according to a result obtained by analyzing each split image data and varies the luminance control signal in synchronization with a period in which the gate driver scans each of the plurality of regions.

3. The OLED display device according to claim 2, wherein, in the split window mode, the data driver sets image data corresponding to a last horizontal line of an Nth region as blank data, sets a specific horizontal period after scanning of the Nth region is terminated, as a blank period, converts the blank data into the data voltage and outputs the data voltage during the blank period and simultaneously stores split image data of an (N+1)th region, provided from the timing controller, in a line memory in an order in which the split image data is input, and converts and outputs the split image data of the (N+1)th region into the data voltage in an order in which the split image data is stored in the line memory after the blank period is terminated, wherein N is a positive integer.

4. The OLED display device according to claim 3, wherein:

in the split window mode, the timing controller varies the luminance control signal to a value corresponding to the (N+1)th region during the blank period between a period for scanning of the Nth region and a period for scanning of the (N+1)th region, and

in the split window mode, the gamma voltage generating circuit converts the reference gamma voltage to a value corresponding to the (N+1)th region in response to the luminance control signal corresponding to the (N+1)th region during the blank period.

5. The OLED display device according to claim 2, wherein:

in the split window mode, the timing controller calculates an average picture level for each of the plurality of regions and generates the luminance control signal for each of the plurality of regions according to the average picture level, and

the timing controller generates the luminance control signal for increasing the reference gamma voltage when an average picture level of each of the plurality of regions is relatively low, and generates the luminance control signal for reducing the reference gamma voltage when the average picture level of each of the plurality of regions is relatively high.

6. The OLED display device according to claim 1, wherein, in the split window mode, the system inserts blank data into a region between neighboring window regions and transmits the blank data.

7. A method of driving an organic light emitting diode (OLED) display device comprising a system configured to split a display panel into a plurality of regions and operate in separate modes comprising a split window mode for transmitting split image data corresponding to respective regions to display different images on the respective regions and a normal mode for transmitting normal image data to display one image on the entire display panel, and a panel driving circuit configured to drive the display panel according to the split image data or the normal image data provided from the system, the method comprising:

varying a plurality of gamma voltage levels to separately controlling luminance or color characteristics of each of the plurality of regions during a blank period between a period for scanning a first window region and a period for scanning a second window region, according to a result obtained by analyzing the split image data by the panel driving circuit; and

controlling a specific region in a lowest luminance state by the panel driving circuit until a user input signal is generated when the user input signal is not present during a predetermined period of time or more in the specific portion of the plurality of regions,

wherein the panel driving circuit includes a gamma voltage generating circuit to vary the plurality of gamma voltage levels to reduce power consumption.

8. The method according to claim 7, wherein the panel driving circuit comprises:

a gate driver configure to sequentially supply scan pulses to gate lines of the display panel and sequentially scan the plurality of regions;

a data driver configured to apply a data voltage to data lines of the display panel;

a timing controller configured to align the split image data or the normal image data provided from the system and supply the split image data or the normal image data to the data driver, generate a gate control signal for control of the gate driver and a data control signal for control of the data driver using an external input synchronization signal, and output a luminance control signal according to a result obtained by analyzing the split image data or the normal image data; and

the gamma voltage generating circuit configured to generate a reference gamma voltage having a level, vary the level of the reference gamma voltage in response to the luminance control signal, and supply the level-varied reference gamma voltage to the data driver,

wherein, in the split window mode, the timing controller varies the luminance control signal according to a result obtained by analyzing each split image data and varies the luminance control signal in synchronization with a period in which the gate driver scans each of the plurality of regions.

9. The method according to claim 8, wherein, in the split window mode, the data driver sets image data corresponding to a last horizontal line of an Nth region as blank data, sets a specific horizontal period after scanning of the Nth region is terminated, as a blank period, converts the blank data into the data voltage and outputs the data voltage during the blank period and simultaneously stores split image data of an (N+1)th region, provided from the timing controller, in a line memory in an order in which the split image data is input, and converts and outputs the split image data of the (N+1)th region into the data voltage in an order in which the split image data is stored in the line memory after the blank period is terminated, wherein N is a positive integer.

10. The method according to claim 9, wherein:

in the split window mode, the timing controller varies the luminance control signal to a value corresponding to the (N+1)th region during the blank period between a period for scanning of the Nth region and a period for scanning of the (N+1)th region; and

in the split window mode, the gamma voltage generating circuit converts the reference gamma voltage to a value corresponding to the (N+1)th region in response to the luminance control signal corresponding to the (N+1) th region during the blank period.

11. The method according to claim 8, wherein:

in the split window mode, the timing controller calculates an average picture level for each of the plurality of regions and generates the luminance control signal for each of the plurality of regions according to the average picture level; and

the timing controller generates the luminance control signal for increasing the reference gamma voltage when an average picture level of each of the plurality of regions is relatively low, and generates the luminance control signal for reducing the reference gamma voltage when the average picture level of each of the plurality of regions is relatively high.

12. The method according to claim 7, wherein, in the split window mode, the system inserts blank data into a region between neighboring window regions and transmits the blank data.

13. An organic light emitting diode (OLED) display device comprising:

a display panel including gate lines and data lines;

a gate driver and a data driver configured to sequentially supply scan pulses to the gate lines panel, and apply a data voltage to the data lines, respectively; and

a panel driving circuit chip including a timing controller, the gate driver, the data driver, and a gamma voltage generating circuit,

wherein the panel driving circuit is configured to;

sequentially receive, from a system, first split image data and then second split image data to split the display panel into a plurality of regions in a split window mode in which different images are respectively displayed on the plurality of regions, and

receive normal image data from the system in a normal mode in which one image is displayed on the entire display panel, and

wherein the gamma voltage generating circuit is configured to vary a plurality of gamma voltage levels to separately control luminance of each region during a blank period between a period for scanning a first window region and a period for scanning a second window region.

14. The OLED display device according to claim 13, wherein the first split image data has relatively high luminance and the second split image data has relatively low luminance.

15. The OLED display device according to claim 14, wherein the panel driving circuit chip is further configured to:

separately control the luminance of the plurality of regions according to a result obtained by analyzing the first and second split image data in the split window mode, and

control a specific region in a lowest luminance state until a user input signal is generated when the user input signal is not present during a predetermined period of time or more in a specific portion of the plurality of regions.

16. The OLED display device according to claim 15, wherein, in the split window mode, the data driver sets image data corresponding to a last horizontal line of an Nth region as blank data, sets a specific horizontal period after scanning of the Nth region is terminated, as a blank period, converts the blank data into the data voltage and outputs the data voltage during the blank period and simultaneously stores split image data of an (N+1)th region, provided from the timing controller, in a line memory in an order in which the split image data is input, and converts and outputs the split image data of the (N+1)th region into the data voltage in an order in which the split image data is stored in the line memory after the blank period is terminated, wherein N is a positive integer.

17. The OLED display device according to claim 13, further comprising:

an average picture level calculator configured to analyze the first and second split image data or normal image data input from the host system to calculate an average picture level (APL); and

a peak luminance controller configured to control maximum luminance of each of the plurality of regions according to the calculated APL from the average picture level calculator.

18. The OLED display device according to claim 17, further comprising:

the gamma voltage generating circuit configured to generate a maximum reference gamma voltage that is maintained at a first level during a period when the gate driver scans a first of the plurality of regions.

19. The OLED display device according to claim 18, wherein the data driver includes a line memory, a latch and a buffer, and the data driver is configured to:

set image data corresponding to a last horizontal line of the first split image data to blank data, and

supply the blank data to the latch during a blank period and simultaneously store the second split image data input from the timing controller in the order in which a plurality of pieces of the second split image data is input.

20. The OLED display device according to claim 18, wherein, in the split window mode, the data driver sets image data corresponding to a last horizontal line of an Nth region as blank data, sets a specific horizontal period after scanning of the Nth region is terminated, as the blank period, converts the blank data into the data voltage and outputs the data voltage during the blank period and simultaneously stores split image data of an (N+1)th region, provided from the timing controller, in the line memory in an order in which the split image data is input, and converts and outputs the split image data of the (N+1)th region into the data voltage in an order in which the split image data is stored in the line memory after the blank period is terminated, wherein N is a positive integer.