DISPLAY APPARATUS AND METHOD OF DRIVING THE SAME

• US 20120081412A1
• Filed: 07/21/2011
• Published: 04/05/2012
• Est. Priority Date: 10/04/2010
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Group)
• Original Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Inventors: YANG, Byungchoon, LEE, Young-keun, KIM, Ho-young, KIM, Heetae, JANG, Hyeonyong, KIM, Dongkwon
• Granted Patent: US 9,417,732 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

A display apparatus includes a display panel, a backlight unit, a backlight control circuit, sensors, a read-out circuit and a sensor auxiliary circuit. The display panel includes pixels and displays an image. The backlight unit includes a first light source which emits a first light in a infrared light range. The backlight control circuit controls a brightness of the first light source. The sensors sense an external signal and outputs first sensing signals. The read-out circuit outputs the first sensing signals as second sensing signals. The sensor auxiliary circuit compares a maximum value and a minimum value of the second sensing signals and provides a brightness control signal to the backlight control circuit based on the compared difference to control the brightness of the first light source.

Claims

1. A display apparatus comprising:

a display panel comprising a plurality of pixels, wherein the display panel displays an image;

a backlight unit comprising a first light source which emits a first light in an infrared light range, the backlight unit providing the first light to the display panel;

a backlight control circuit which controls a brightness of the first light source;

a plurality of sensors which senses an external signal and outputs a plurality of first sensing signals;

a read-out circuit which stores the plurality of first sensing signals and outputs a plurality of second sensing signals during a predetermined time period; and

a sensor auxiliary circuit which receives the plurality of second sensing signals, compares a maximum value and a minimum value in the plurality of second sensing signals and provides a brightness control signal to the backlight control circuit based on the compared difference to control the brightness of the first light source.

2. The display apparatus of claim 1, wherein the sensor auxiliary circuit comprises:

a data selector which receives the plurality of second sensing signals and outputs the maximum value and the minimum value;

a comparator which compares a difference between the maximum value and the minimum value with a predetermined reference value, outputs a first control signal when the difference between the maximum value and the minimum value is greater than or equal to the reference value, and outputs a second control signal when the difference between the maximum value and the minimum value is less than the reference value; and

a control signal generator which outputs a first brightness control signal in response to the first control signal to maintain the brightness of the first light source and outputs a second brightness control signal in response to the second control signal to increase the brightness of the first light source.

3. The display apparatus of claim 1, wherein the plurality of sensors comprise:

a visible light sensor which senses light in the visible light range; and

an infrared light sensor which senses light in the infrared light range.

4. The display apparatus of claim 3, wherein the visible light sensor and the infrared light sensor are alternately arranged between two adjacent pixels as viewed from a top plan view.

5. The display apparatus of claim 1, wherein the display panel comprises:

a first substrate; and

a second substrate comprising a plurality of color filters and disposed opposite to the first substrate,

wherein the plurality of sensors is disposed inside the second substrate.

6. The display apparatus of claim 1, wherein the backlight control circuit increases the brightness of the first light source using a pulse-width modulation method.

7. The display apparatus of claim 1, wherein the backlight control circuit increases the brightness of the first light source using a pulse-amplitude modulation method.

8. The display apparatus of claim 1, further comprising a timing controller which receives the plurality of second sensing signals from the read-out circuit and provides the plurality of second sensing signals to the sensor auxiliary circuit in response to a sensor test signal, wherein the sensor test signal is provided from an external device or generated from the timing controller.

9. The display apparatus of claim 8, wherein the sensor auxiliary circuit is included in the timing controller.

10. The display apparatus of claim 1, further comprising a scan driver which sequentially applies a scan signal to the plurality of sensors,

wherein the display panel further comprises:

a plurality of scan lines which sequentially receives the scan signal; and

a plurality of read-out lines which receives the plurality of first sensing signals from the plurality of sensors.

11. The display apparatus of claim 1, wherein the read-out circuit comprises:

a plurality of operational amplifiers, wherein each of the plurality of operational amplifiers receives a corresponding first sensing signal of the plurality of first sensing signals from a corresponding read-out line of the plurality of read-out lines and compares the corresponding first sensing signal to a predetermined reference voltage to output a difference between the first sensing signal and the reference voltage as a corresponding second sensing signal when the first sensing signal is greater than the reference voltage;

a read-out part which sequentially outputs the plurality of second sensing signals in response to a plurality of switching signals; and

a shift register which sequentially provides the plurality of switching signals to the read-out part.

12. The display apparatus of claim 1, wherein the backlight unit further comprises a second light source which emits a second light in a visible light range, and the backlight unit provides the second light to the display panel.

13. The display apparatus of claim 1, wherein the read-out circuit outputs the plurality of first sensing signals as the plurality of second sensing signals.

14. A method of driving a display apparatus, comprising:

receiving a plurality of first sensing signals corresponding to an external signal;

storing the plurality of first sensing signals and outputting a plurality of second sensing signals at a predetermined time;

comparing a difference between a maximum value and a minimum value of the plurality of second signals with a reference value; and

controlling a brightness of an infrared-light light source in the backlight unit based on the compared difference.

15. The method of claim 14, further comprising:

outputting a first control signal when the difference between the maximum value and the minimum value is greater than or equal to the reference value; and

outputting a second control signal when the difference between the maximum value and the minimum value is less than the reference value.

16. The method of claim 15, wherein controlling the brightness of the infrared-light light source comprises:

outputting a first brightness control signal in response to the first control signal to maintain the brightness of the infrared-light light source; and

outputting a second brightness control signal in response to the second control signal to increase the brightness of the infrared-light light source.

17. The method of claim 14, further comprising extracting the maximum value and the minimum value from the plurality of second sensing signals.

18. The method of claim 14, wherein controlling the brightness of the infrared-light light source comprises:

calculating a value corresponding to a brightness increase of the infrared-light light source based on the reference value and the difference between the maximum value and the minimum value; and

controlling the brightness of the infrared-light light source based on the calculated value corresponding to the brightness increase.

19. The method of claim 14, wherein the brightness of the infrared-light light source is controlled using a pulse-width modulation method.

20. The method of claim 14, wherein the brightness of the infrared-light light source is controlled using a pulse-amplitude modulation method.