Patent Application
20110181202
The disclosed embodiments of the present invention relate to controlling a backlight module, and more particularly, to a local dimming control apparatus and method of an edge-type backlight module.
In a conventional liquid crystal display (LCD) apparatus, a light source of a direct-type backlight module is commonly implemented by fluorescent tube(s). Due to the advance of the LCD technology, a partially-driven direct-type backlight module is developed, where a number of point light sources, such as light emitting diodes (LEDs), are used in a plurality of backlight units disposed below a plurality of regions of a display panel and implemented for illuminating the regions, respectively and independently. Therefore, the light intensity of the backlight module is partially changed rather than globally changed, which can improve the display quality of the video image.
However, due to consideration of low cost and small size, an edge-type backlight module is preferred. The conventional edge-type backlight module has a number of point light sources, such as LEDs arranged at a side of the LCD panels. As the local dimming control of the backlight module would affect the final display quality of the video image, how to properly control the edge-type backlight module becomes an important topic to designers in this field.
In accordance with exemplary embodiments of the present invention, a local dimming control apparatus and method of an edge-type backlight module are proposed.
According to one aspect of the present invention, a local dimming control apparatus of an edge-type backlight module is proposed. The edge-type backlight module has a plurality of backlight units positioned at least one side of a display area. The local dimming control apparatus includes: a configuration unit, for dividing the display area into a plurality of display blocks; and a local dimming control unit, coupled to the configuration unit, for setting respective backlight intensities of the display blocks through controlling a plurality of luminance settings of the backlight units.
According to another aspect of the present invention, a local dimming control method of an edge-type backlight module is proposed. The edge-type backlight module has a plurality of backlight units positioned at least one side of a display area. The local dimming control method includes the following steps: dividing the display area into a plurality of display blocks; and performing a local dimming control operation to set respective backlight intensities of the display blocks through controlling a plurality of luminance settings of the backlight units.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms “include” and “comprise” are used in an open-ended fashion, and thus should be interpreted to mean “include, but not limited to . . . ”. Also, the term “couple” is intended to mean either an indirect or direct electrical connection. Accordingly, if one device is coupled to another device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.
D
MN
=u
1
MN
×U
1
+u
2
MN
×U
2
+ . . . +u
10
MN
×U
10
+b
1
MN
×B
1
+b
2
MN
×B
2
+ . . . +b
10
MN
×B
10
+l
1
MN
×L
1
+l
2
MN
×L
2
+ . . . +l
6
MN
×L
6
+r
1
MN
×R
1
+r
2
MN
×R
2
+ . . . +r
6
MN
×R
6 (1)
In above equation (1), u1
At the condition that local dimming control is employed, the desired luminance DMN of each display block DBMN (M=1˜10 and N=1˜6) may be determined by pixel data content of each display block DBMN and is known. The desired luminance of each of the display blocks DB11-DB16, DB21-DB26, . . . , DB101-DB106 can be expressed according to equation (1). Taking the display blocks DB11 and DB12 for example, the desired luminance D11 and D12 thereof can be expressed as follows.
D
11
=u
1
11
×U
1
+u
2
11
×U
2
+ . . . +u
10
11
×U
10
+b
1
11
×B
1
+b
2
11
×B
2
+ . . . +b
10
11
×B
10
+l
1
11
×L
1
+l
2
11
×L
2
+ . . . +l
6
11
×L
6
+r
1
11
×R
1
+r
2
11
×R
2
+ . . . +r
6
11
×R
6 (2)
D
12
=u
1
12
×U
1
+u
2
12
×U
2
+ . . . +u
10
12
×U
10
+b
1
12
×B
1
+b
2
12
×B
2
+ . . . +b
10
12
×B
10
+l
1
12
×L
1
+l
2
12
×L
2
+ . . . +l
6
12
×L
6
+r
1
12
×R
1
+r
2
12
×R
2
+ . . . +r
6
12
×R
6 (3)
As there are 10*6 display blocks DB11-DB16, DB21-DB26, . . . , DB101-DB106, 10*6 equations are required to express the desired luminance values of the display blocks DB11-DB16, DB21-DB26, . . . , DB101-DB106 in terms of luminance values of the backlight units U1-U10, B1-B10, L1-L6 and R1-R6; however, only 2*(10+6) variables (i.e., luminance values of backlight units U1-U10, B1-B10, L1-L6 and R1-R6 to be controlled) are included therein due to the fact that the desired luminance values (i.e., D11-D16, D21-D26, . . . , D101-D106) and all the weighting factors are known. Since the number of variables is smaller than the number of equations (i.e., 2*(10+6)<10*6), no solution can be successfully found. As a result, the local dimming control would fail under such a panel division.
To solve the above-mentioned problem, the configuration unit 110 is particularly devised to divide the display area 108 into a plurality of display blocks according to the number of the backlight units 105 included in the edge-type backlight module 104. In one implementation, the number of the configured display blocks is equal to the number of the backlight units 105. Thus, only one solution would be found since the number of variables is equal to the number of equations. By way of example, based on the found solution, the backlight intensity provided by a backlight unit may be zero or other luminance value. In another implementation, the number of the configured display blocks is smaller than the number of the backlight units. Thus, more than one solution would be found since the number of variables is smaller than the number of equations. It should be noted that any of the solutions can be used to set the luminance values of the backlight units 105.
D′
MN
=u′
1
MN
×U
1
+u′
2
MN
×U
2
+ . . . +u′
10
MN
×U
10
+b′
1
MN
×B
1
+b′
2
MN
×B
2
+ . . . +b′
10
MN
×B
10
+l′
1
MN
×L
1
+l′
2
MN
×L
2
+ . . . +l′
6
MN
×L
6
+r′
1
MN
×R
1
+r′
2
MN
×R
2
+ . . . +r′
6
MN
×R
6 (4)
As there are 8*4 display blocks DB11-DB14, DB21-DB24, . . . , DB81-DB84, 8*4 equations are required to express the desired luminance values of the display blocks DB11-DB14, DB21-DB24d, . . . , DB81-DB84. In this embodiment, 2*(10+6) variables (i.e., luminance values of backlight units U1-U10, B1-B10, L1-L6 and R1-R6 to be controlled) are included in the equations due to the fact that the desired luminance values (i.e., D′11-D′14, D′21-D′24, . . . , D′81-D′84) of the display blocks and all the weighting factors are known. Since the number of variables is equal to the number of equations (i.e., 2*(10+6)=8*4), only one solution can be found. Thus, the local dimming control can be successfully realized by referring to the found solution.
D
M
=u
1
M
×U
1
+u
2
M
×U
2
+ . . . +u
10
M
×U
10
+b
1
M
×B
1
+b
2
M
×B
2
+ . . . +b
10
M
×B
10
+l
1
M
×L
1
+l
2
M
×L
2
+ . . . +l
6
M
×L
6
+r
1
M
×R
1
+r
2
M
×R
2
+ . . . +r
6
M
×R
6 (5)
As there are 8*4 display blocks DB1-DB32, 8*4 equations are required to express the desired luminance values of the display blocks DB1-DB32. In this embodiment, 2*(10+6) variables (i.e., luminance values of backlight units U1-U10, B1-B10, L1-L6 and R1-R6 to be controlled) are included in the equations due to the fact that the desired luminance values (i.e., D1-D32) of the display blocks and all the weighting factors are known. Since the number of variables is equal to the number of equations (i.e., 2*(10+6)=8*4), only one solution can be found. Thus, the local dimming control can be successfully realized by referring to the found solution.
In above exemplary embodiments, the edge-type backlight module 104 has backlight units 105 positioned at four sides of the rectangular display area 108. However, regarding a case where the edge-type backlight module 104 has backlight units 105 that are not positioned at all sides of the rectangular display area 108, the same objective of performing local dimming control upon the edge-type backlight module 104 can be achieved. Please refer to
D″
MN
=u″
1
MN
×U
1
+u″
2
MN
×U
2
+ . . . +u″
10
MN
×U
10
+b″
1
MN
×B
1
+b″
2
MN
×B
2
+ . . . +b″
10
MN
×B
10 (6)
As there are 10*2 display blocks DB11-DB21, DB21-DB22, . . . , DB101-DB102, 10*2 equations are required to express the desired luminance values of the display blocks DB11-DB21, DB21-DB22, . . . , DB101-DB102. In addition, 2*10 variables (i.e., luminance values of backlight units U1-U10 and B1-B10 to be controlled) are included in the equations due to the fact that the desired luminance values (i.e., D″11-D″12, D″21-D″22, . . . , D″101-D″102) of the display blocks and all the weighting factors are known. Since the number of variables is equal to the number of equations, only one solution can be found. Thus, the local dimming control can be successfully realized by referring to the found solution.
Provided that the light guide plate and/or other optical component(s) in the backlight module are properly designed to make weighting factors of the backlight units 105 constant for each display block configured by the configuration unit 110, the local dimming control can be successfully performed upon each display block through controlling luminance settings of all backlight units 105 as long as the configuration unit 110 divides the display area 108 of the display panel 106 into display blocks whose number is not greater than the number of the backlight units 105. It should be noted that the size and/or the shape of the configured display block can be adjustable, depending upon design requirements. For example, the display blocks are not required to be arranged in the matrix format or radial format, and the display blocks are not required to have the same size/shape. These alternative panel division designs all fall within the scope of the present invention.
Briefly summarized, as long as backlight intensities of a plurality of display blocks in a display area can be respectively set by using the same backlight control which includes luminance settings of a plurality of backlight units positioned at one or more sides of the display area, any rule of defining the display blocks in the display area can be employed by the configuration unit 110 shown in
Step 602: Divide the display area into a plurality of display blocks according to the number of the backlight units. By way of example, the number of the display blocks is equal to or smaller than the number of the backlight units; in addition, the display blocks may be arranged in a matrix format or a radial format.
Step 604: For each of the display blocks, set a luminance value (backlight intensity) of the display block by controlling a plurality of luminance settings of the backlight units. Therefore, the local dimming control applied to the backlight intensities of the display blocks is achieved through controlling the luminance settings of the backlight units. As the number of variables is equal to or smaller than the number of equations, at least one solution can be found. Thus, based on the found solution of the luminance settings (luminance values) of the backlight units, the local dimming control can be successfully realized.
As the details of the exemplary local dimming control method can be found in above paragraphs directed to the diagrams shown in the accompanying drawings, further description is omitted here for brevity.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.
