Liquid crystal display device and driving method thereof

• US 9,870,740 B2
• Filed: 06/09/2015
• Issued: 01/16/2018
• Est. Priority Date: 09/16/2014
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Park, Se-Ki, Kwon, Yong-Hoon, You, Bong-Hyun, Goh, Joon-Chul
• Primary Examiner(s): Lee, Benjamin C
• Assistant Examiner(s): Michaud, Robert
• Application Number:
  US14/734,884
• Publication Number:
  US 20160078819A1
• Time in Patent Office: 952 Days
• CPC Class Codes: G06F 3/005 Input arrangements through a video camera
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/068 for control of viewing angle adjustment
• CPC Class Codes: G09G 2320/0686 with two or more screen areas displaying information with different brightness or colours
• CPC Class Codes: G09G 2354/00 Aspects of interface with display user
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A liquid crystal display panel comprises a backlight unit including an optical assembly and configured to differentiate the liquid crystal display panel into a plurality of blocks and to illuminate light to each of the plurality of blocks; a location sensor configured to sense a location of a user watching the liquid crystal display panel; a backlight controller configured to output a dimming value corresponding to a brightness of each of the plurality of blocks according to a result of sensing by the location sensor; and a backlight driver configured to generate a driving current corresponding to the dimming value of each block and to provide the generated driving current to the backlight unit corresponding to each of the plurality of blocks.

Claims

1. A liquid crystal display device, comprising:

a liquid crystal display panel;

a backlight unit, including an optical assembly, to differentiate the liquid crystal display panel into a plurality of blocks and to independently control illumination light of each of the plurality of blocks;

a location sensor to sense a location of a user watching the liquid crystal display panel;

a backlight controller to output a final dimming value corresponding to a brightness of each of the plurality of blocks according to the sensed location of the user, wherein the backlight controller comprises;

a location determiner to determine the user'"'"'s location including left side or right side information with respect to the display panel by comparing the result of sensing sensed by the location sensor with a reference value;

a left/right side block dimming value control determiner to determine whether or not to control a dimming value of the backlight unit corresponding to a left side or right side block of the liquid crystal display panel according to the user'"'"'s left or right side, respectively determined by the location determiner;

a rise current calculator to calculate a rise current Iup of the corresponding block according to a result of determination by the left/right side block dimming value control determiner using math formula 1;

Iup=(Imax−

Inormal)/90×

(90−

θ

) and math formula 2;

Iup=(Imax−

Inormal)/90×

(θ

−

90), a maximum current of each block of the liquid crystal display panel being Imax, an average current of the each block being Inormal, and the user'"'"'s location being θ

; and

a final dimming value per block generator to generate the final dimming value of each of the plurality of blocks reflecting a value calculated by the rise current calculator; and

a backlight driver to generate a driving current corresponding to the final dimming value of each block and to provide the generated driving current to the backlight unit corresponding to each of the plurality of blocks, the liquid crystal display panel being interposed between the user and the backlight unit to receive light output from the backlight unit and to produce images therefrom that are viewable by the user.

2. The liquid crystal display device of claim 1, wherein the optical assembly comprises:

a plurality of light source units including at least one light emitting device to emit light;

a light guide panel comprising an incident surface where light is received from the light source units, an exit surface emitting the light to the liquid crystal display panel, the liquid crystal display panel facing the exit surface, the light guide panel further comprising a rear surface where a plurality of optical patterns are formed; and

an optical sheet arranged on an upper part of the light guide panel to change characteristics of the light emitted from the light guide panel.

3. The liquid crystal display device of claim 2, wherein the optical pattern comprises a micro lens pattern.

4. The liquid crystal display device of claim 1, wherein the location sensor comprises an eye tracking sensor to identify a location of the user'"'"'s pupil.

5. The liquid crystal display device of claim 4, wherein the location sensor measures an angle between the user'"'"'s pupil and the backlight unit using the eye tracking sensor.

6. The liquid crystal display device of claim 1, wherein the reference value comprises first and second reference values, the first reference value being 75°

and the second reference value being 105°

.

7. The liquid crystal display device of claim 1, wherein the rise current calculator calculates the rise current, Iup, using math formula 1 in response to the user being located on a left side of the liquid crystal display panel, and calculates the rise current, Iup, using math formula 2 in response to the user being located on a right side of the liquid crystal display panel.

8. The liquid crystal display device of claim 1, wherein the backlight controller increases a brightness of each block of the liquid crystal display panel corresponding to an opposite side of the user'"'"'s location.

9. The liquid crystal display device of claim 1, wherein the backlight controller increases brightness of only some of the blocks of the liquid crystal display panel in response to the user watching the liquid crystal display panel from one of the left side and the right side.

10. The liquid crystal display device of claim 1, wherein the optical assembly comprises:

a light guide panel having a first major surface opposite a second major surface, and a plurality of side surfaces connecting the second major surface to the first major surface, the first major surface facing the user and the liquid crystal display panel; and

a light source that includes a plurality of light emitting diode packages arranged along a one of the side edges of the light guide panel to input light into the light guide panel, each of the light emitting diode packages corresponds to one of the plurality of blocks, each of the blocks corresponds to a different vertical strip of the liquid crystal display panel.

11. The liquid crystal display device of claim 10, wherein each of the light emitting diode packages composes two light sources.

12. The liquid crystal display device of claim 1, wherein the location sensor determines an angle between the user and a surface of the display panel, and the backlight controller and the backlight driver to control driving currents to the different blocks according to the determined angle.

13. The liquid crystal display device of claim 12, wherein rightmost of the blocks are driven at a higher current and are brightened when the user is arranged substantially left of a center of a front surface of the liquid crystal display panel, wherein leftmost of the blocks are driven at a higher current and are brightened when the user is arranged substantially to the right of the center of the front surface of the liquid crystal display panel, and wherein all of the blocks are driven normally when the user is arranged substantially in front of the center of the front surface of the liquid crystal display panel.

14. A method of driving a liquid crystal display device, comprising:

providing a backlight controller that controls a backlight unit that illuminates a liquid crystal display panel within the liquid crystal display device;

differentiating the backlight unit corresponding to the liquid crystal display panel into a plurality of blocks that correspond to light source units used to illuminate the backlight unit;

sensing a location of a user watching the liquid crystal display panel with respect to the liquid crystal display panel;

determining, via a location determiner within the backlight controller, the user'"'"'s location including left side or right side information with respect to the liquid crystal display panel by comparing a result of the sensing with a reference value;

determining whether or not to control a dimming value of the backlight unit corresponding to a left side or a right side of the liquid crystal display panel according to the user'"'"'s left side or right side, respectively determined by the location determiner via a left/right side block dimming value control determiner of the backlight controller;

calculating a rise current Iup of the corresponding block according to a result of the determining by the left/right side block dimming value control determiner via a rise current calculator of the backlight controller using math formula 1;

Iup=(Imax−

Inormal)/90×

(90−

θ

) and math formula 2;

Iup=(Imax−

Inormal)/90×

(θ

−

90), a maximum current of each block of the liquid crystal display panel being Imax, an average current of the each block being Inormal, and the user'"'"'s location being θ

;

generating a final dimming value of each block reflecting the user'"'"'s location via a final dimming value per block generator of the backlight controller;

outputting the final dimming value of each block corresponding to a brightness of each of the plurality of blocks according to the user'"'"'s location with respect to the liquid crystal display panel;

generating a backlight driving current corresponding to the final dimming value of each block; and

generating light according to the backlight driving current and providing the generated light to the liquid crystal display panel.

15. The method of claim 14, wherein the determining the user'"'"'s location with respect to the liquid crystal display panel comprises identifying a location of the user'"'"'s pupil and measuring angle θ

between the user'"'"'s pupil and the liquid crystal display panel.

16. The method of claim 15, wherein the reference value comprises first and second reference values, the first reference value being 75°

and the second reference value being 105°

.

17. The method of claim 15, wherein an illumination of the generated light of each block is adjusted according only to a location of the user with respect to the liquid crystal display panel and not according to a direction a user'"'"'s eyes are directed, wherein when the user is detected as being substantially to the right side of the liquid crystal display panel, only blocks corresponding to the left side of the liquid crystal display panel are brightened, wherein when the user is detected as being substantially to the left side of the liquid crystal display panel, only blocks corresponding to the right side of the liquid crystal display panel are brightened, and when the user is detected as being in front of the central portion of the liquid crystal display panel, all of the blocks are driven normally to produce a normal brightness.