Display apparatus and method for improving image quality thereof

• US 8,816,955 B2
• Filed: 07/11/2011
• Issued: 08/26/2014
• Est. Priority Date: 11/01/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kang, Jeong-il, Cho, Kun-ho
• Primary Examiner(s): Mengistu, Amare
• Assistant Examiner(s): MATHEWS, CRYSTAL
• Application Number:
  US13/179,644
• Publication Number:
  US 20120105518A1
• Time in Patent Office: 1,142 Days
• Field of Search: 345/102, 345/690, 345/694, 315/295
• US Class Current: 345/102
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

A display apparatus includes a liquid crystal panel; a light guide plate disposed at a rear side of the liquid crystal panel; at least one LED module disposed in at least one side of the light guide plate and including a plurality of LEDs; a driver which drives the plurality of LEDs; an image analyzer which analyzes an input image; and a switch unit which turns off at least one LED among the plurality of LEDs while a remainder of the plurality of LEDs are being driven by the driver, according to a result of the analyzing the input image, wherein the at least one LED is disposed closer to a corner of the liquid crystal panel than the remainder of the plurality of LEDs.

Claims

1. A display apparatus comprising:

a liquid crystal panel;

a light guide plate disposed at a rear side of the liquid crystal panel;

at least one LED module disposed in at least one side of the light guide plate comprising;

a plurality of LEDs;

a first terminal connected to an anode of a first LED placed at one end of the plurality of LEDs connected in series,

a second terminal connected to a cathode of the first LED, and

a third terminal connected to a cathode of a last LED placed at the other end of the plurality of LEDs connected in series;

a driver which drives the plurality of LEDs comprising;

a plus terminal and

a minus terminal,

wherein the first terminal is connected to the plus terminal, and the third terminal is connected to the minus terminal;

an image analyzer which analyzes an input image; and

a switch unit which comprises;

a first resistor directly connected to the first terminal at one end and to a first node at the other end,

a second resistor directly connected to the first node at one end and to a second node at the other end,

a third resistor directly connected to the first node at one end and to a third node at the other end,

a first transistor directly connected to the third node at a gate terminal, to the first terminal at a source terminal, and to the second terminal at a drain terminal, and

a second transistor directly connected to the second node at a drain terminal, an external signal being applied to a gate terminal of the second transistor, and a source terminal of the second transistor being grounded,

wherein, according to a result of the analyzing the input image, the switch unit turns off at least one LED among the plurality of LEDs while the driver drives a remainder of the plurality of LEDs, wherein the at least one LED is disposed closer to a corner of the liquid crystal panel than the remainder of the plurality of LEDs.

2. The display apparatus of claim 1, wherein the first transistor is a P-channel metal oxide semiconductor (PMOS) and the second transistor is an N-channel metal oxide semiconductor (NMOS).

3. The display apparatus of claim 1, wherein the external signal is a control signal which controls not to apply current to the at least one LED, based on a result of the analyzing the input image.

4. The display apparatus of claim 1, wherein the at least one LED module comprises a first LED module and a second LED module, and the plurality of LEDs comprises a first plurality of LEDs included in the first LED module and a second plurality of LEDs included in the second LED module,

wherein the first LED module comprises a first terminal, a second terminal, a third terminal, and a fourth terminal,

wherein the first terminal is connected to a cathode of a first LED placed at one end of the first plurality of LEDs connected in series, the second terminal is connected to an anode of the first LED, the third terminal is connected to an anode of a second LED connected to the first LED, and the fourth terminal is connected to a cathode of a last LED placed at the other end of the first plurality of LEDs connected in series.

5. The display apparatus of claim 4, wherein the second LED module has the same structure as the first LED module.

6. The display apparatus of claim 1, wherein the switch unit turns off the at least one LED while the remainder of the plurality of LEDs are being driven by the driver when the image analyzer determines at least one of:

(i) that the input image to be displayed on the liquid crystal panel is in a given format; and

(ii) that a pixel value of the input image to be displayed at the corner of the liquid crystal panel is lower than a pixel value of the input image to be displayed at a neighbor region.

7. The display apparatus of claim 6, further comprising a storage unit which pre-stores information which the image analyzer uses to determine the at least one of (i) and (ii).

8. The display apparatus of claim 6, wherein the given format is a letterbox format.

9. The display apparatus of claim 1, further comprising a storage unit which pre-stores information about the at least one LED to be turned off according to the result of the analyzing the input image.

10. The display apparatus of claim 9, wherein the pre-stored information about the at least one LED to be turned off comprises information about at least one of a location of the at least one LED in the at least one LED module and a number of the at least one LED among the plurality of LEDs.

11. The display apparatus of claim 1, further comprising a user input unit which receives a user command to control the switch unit to turn off the at least one LED without regard to the result of the analyzing the input image.

12. A display apparatus comprising:

a display substrate on which an input image is displayed;

a light guide plate disposed at a rear side of the display substrate;

at least one light source module disposed in at least one side of the light guide and comprising;

a plurality of light sources;

a first terminal connected to an anode of a first light source placed at one end of the plurality of light sources connected in series,

a second terminal connected to a cathode of the first light source, and

a third terminal connected to a cathode of a last light source placed at the other end of the plurality of light sources connected in series; and

a controller comprising;

a plus terminal and

a minus terminal,

wherein the first terminal is connected to the plus terminal, and the third terminal is connected to the minus terminal;

a first resistor directly connected to the first terminal at one end and to a first node at the other end,

a second resistor directly connected to the first node at one end and to a second node at the other end,

a third resistor directly connected to the first node at one end and to a third node at the other end,

a first transistor directly connected to the third node at a gate terminal, to the first terminal at a source terminal, and to the second terminal at a drain terminal, and

a second transistor directly connected to the second node at a drain terminal, an external signal being applied to a gate terminal of the second transistor, and a source terminal of the second transistor being grounded,

wherein the controller turns on and off at least one light source among the plurality of light sources while a remainder of the plurality of light sources are turned on to display the input image on the display substrate.

13. The display apparatus of claim 12, further comprising at least one of an image analyzer, which analyzes the input image, and a user input which receives a user command,

wherein the at least one light source to be turned on and off is selected by the controller according to a result of the analyzing the input image or the user command.

14. The display apparatus of claim 12, wherein the controller turns off the at least one light source while the remainder of the plurality of light sources are turned on to display the input image, when it is determined that light leakage blurring the display substrate is to occur at a region of the display substrate which is disposed closer to the at least one light source than a remaining region of the display substrate.

15. The display apparatus of claim 13, wherein the controller turns off the at least one light source while the remainder of the plurality of light sources are turned on to display the input image when the image analyzer determines at least one of:

(i) that the input image to be displayed on the display substrate is in a given format; and

(ii) that a pixel value of the input image to be displayed at a region in the display substrate corresponding to the at least one light source is lower than a pixel value of the input image to be displayed at a neighbor region in the display substrate.

16. The display apparatus of claim 15, further comprising a storage substrate which pre-stores information required by the image analyzer to determine the at least one of (i) and (ii).