Flexible display device and driving method thereof

1. A display device comprising:

a self-luminous flexible display panel moveable along a first direction, comprising a recognition pattern, the recognition pattern comprising a plurality of indicators;

a housing coupled to the flexible display panel, configured such that as the flexible display panel is withdrawn from the housing or retracted into the housing along the first direction, a display area of the flexible display panel, is variably exposed; and

a light-receiving sensor positioned in the housing corresponding to the recognition pattern configured to recognize one of the plurality of indicators and sense the exposed display area of the flexible display panel; and

a controller in electrical communication with the light-receiving sensor and the flexible display panel, the controller configured to display a variable-size image on the flexible display panel, the displayed image having a variable-size area, wherein the variable-size area of the displayed image corresponds to the sensed exposed display area of the flexible display panel;

wherein the display area of the flexible display panel includes a display area comprising a plurality of pixels configured to display an image and a non-display area near the display area, and wherein the recognition pattern is positioned in the non-display area; and

wherein the plurality of indicators are pixels respectively having different colors, and the light-receiving sensor is configured to sense the color of the plurality of indicators to sense the exposed display area.

2. The display device of claim 1 , wherein the controller includes a storage unit storing image size data respectively corresponding to the display area of the flexible display panel.

3. The display device of claim 1 , wherein the plurality of indicators include subpixels of red, green, and blue.

4. The display device of claim 3 , wherein a portion of pixels of the plurality of pixels formed in the flexible display panel are respectively allocated as indicators.

5. The display device of claim 3 , wherein the plurality of indicators include a driving circuit unit and an organic light emitting diode (OLED) connected to the driving circuit unit.

6. The display device of claim 1 , wherein the plurality of indicators respectively have different light-emitting intensities, and the light-receiving sensor includes a light-receiving photosensor configured to sense the light intensity of the plurality of indicators.

7. The display device of claim 6 , wherein the plurality of indicators represent the same color and have light-emitting intensity that varies gradually along the first direction.

8. The display device of claim 1 , further comprising:

a roll part positioned inside the housing and fixing one end of the flexible display panel; and

a fixing member fixing the other end of the flexible display panel.

9. The display device of claim 8 , further comprising

a pair of approach sensors, wherein one of the pair of approach sensors is installed in housing and the other of the pair of approach sensors is installed in the fixing member toward the housing, the pair of approach sensors configured to sense when the flexible display panel is disposed substantially entirely within housing, based on the distance between the housing and the fixing member.

10. A method of driving a display device, comprising:

providing the display device according to claim 1 ;

activating the plurality of indicators;

recognizing a color of one indicator among the plurality of indicators using the light-receiving sensor to determine an exposed display area of the flexible display panel;

generating an image signal corresponding to the display area; and

displaying the image in the display area of the flexible display panel.

11. The method of claim 10 , further comprising inactivating the indicators among the plurality of indicators exposed outside the housing before the flexible display panel displays the image.

12. The method of claim 11 , further comprising:

determining whether another indicator is sensed after the flexible display panel displays the image; and

activating the plurality of indicators if another indicator is not sensed with reference to the currently sensed indicator.

13. A method of driving a display device, comprising:

providing the display device according to claim 9 ;

determining whether an approach sensor is in an open state;

activating a plurality of indicators if the approach sensor is in the open state;

recognizing one indicator among the plurality of indicators through the light-receiving sensor to sense an exposed display area of the flexible display panel;

generating an image signal corresponding to the display area;

displaying an image from the image signal on the display area of the flexible display panel; and

determining whether the approach sensor is in a closed state to inactivate the plurality of indicators if the approach sensor is in the closed state, thereby initiating a power-saving mode.

14. The method of claim 13 , further comprising inactivating the indicators among the plurality of indicators which are exposed outside the housing before the flexible display panel displays the image.

15. The method of claim 14 , wherein:

after the flexible display panel displays the image, determining whether another indicator is sensed with reference to the currently sensed indicator; and

activating a plurality of indicators if another indicator is not sensed with reference to the currently sensed indicator.

16. A display device comprising:

a self-luminous flexible display panel moveable along a first direction, comprising a recognition pattern, the recognition pattern comprising a plurality of indicators;

a housing coupled to the flexible display panel, configured such that as the flexible display panel is withdrawn from the housing or retracted into the housing along the first direction, a display area of the flexible display panel, is variably exposed; and

a light-receiving sensor positioned in the housing corresponding to the recognition pattern configured to recognize one of the plurality of indicators and sense the exposed display area of the flexible display panel; and

a controller in electrical communication with the light-receiving sensor and the flexible display panel, the controller configured to display a variable-size image on the flexible display panel, the displayed image having a variable-size area, wherein the variable-size area of the displayed image corresponds to the sensed exposed display area of the flexible display panel;

wherein the display area of the flexible display panel includes a display area comprising a plurality of pixels configured to display an image and a non-display area near the display area, and wherein the recognition pattern is positioned in the non-display area; and

wherein the plurality of indicators are pixels respectively having different light-emitting intensities, and the light-receiving sensor includes a light-receiving photosensor configured to sense the light intensity of the plurality of indicators to sense the exposed display area.