Patent Grant
7911443
This Non-provisional application claims priority under 35 U.S.C. ยง119(a) on Patent Application No(s). 095132244 filed in Taiwan, Republic of China on Aug. 31, 2006, and 096130724 filed in Taiwan, Republic of China on Aug. 20, 2007, the entire contents of which are hereby incorporated by reference.
1. Field of Invention
The invention relates to a driving-control device and a driving-control method of a backlight module, and, in particular, to a driving-control device and a driving-control method of a backlight module having a sequential flashing function.
2. Related Art
Nowadays, liquid crystal displays (LCD) are being used widely. They can be found on computer monitors, touch-screens for man-machine interface and home televisions. As popularity grows, its technical performance becomes more demanding in parameters such as viewing angle, contrast ratio, color saturation, and response time.
Among all the performance parameters, quick response time has always been one of the most sought-after items in improving motion picture quality. Low quality LCD with slow response time often causes picture blurring while viewing moving objects. This may not be a major issue if the LCD is just for a desktop computer monitor on which most of the pictures are still all the time. However, if the LCD is for home televisions, quicker response time is a must.
Besides the response time, there is a fundamental technical issue, the display type (or mode), that limits the LCD motion picture quality. The CRT display device, the predecessor of LCD, displays pictures by tracing out the images on a glass screen with a single scanning electron beam. Therefore, at any given moment, only a small fraction of the glass screen will be lightened while being scanned across by the electron beam. CRT display device cannot hold still the complete picture to be displayed on the glass screen. Actually, it displays pictures dot-by-dot and line-by-line. This is referred to as impulse-type display. LCD displays pictures in a different way. The LCD screen is composed of numerous pixels arrayed in rows and columns. Each pixel stores a graphic data. To display a picture, the LCD screen loads pixel data of a complete frame in parallel. Each pixel keeps its graphic data until being reloaded. At any given time, every pixel of the entire screen is lightened. Hence, LCD can hold still the complete picture to be displayed, so it displays pictures frame-by-frame. This is referred to as holding-type display.
A major drawback of holding-type display is the picture blurring caused by frame switching when displaying moving objects. Because the previous frame will never completely disappear from the screen before the next frame comes in. The most straightforward way to solve this problem is to make the previous frame disappear completely by inserting an extra dark frame before the next frame comes in. This will require some efforts on graphic processor. Another simpler solution is to shut off the backlight module of the LCD device for a specific period of time to create a momentary dark image. This dark image neutralizes human eyes from the previous frame and makes them ready to accept the next one. This is referred to as flashing backlight technology. To further eliminate blurring of holding-type display and mimic impulse-type display, an LCD backlight module is divided into several light zones. Each zone can be turned on and off sequentially. A specific control timing sequence is used to turn on and off each light zone. This timing sequence is synchronized to the frame data reload timing to optimize the motion picture quality. This is referred to as sequential flashing backlight technology. Since this sequential flashing backlight technique turns on and off a number of individual light zones, this can also be applied to power-saving and brightness-dimming control.
In some related arts, analog phase delay array is adopted to do the backlight on/off control. However, the timing sequence is adjusted by altering resistance or capacitance value of the control circuit. Therefore, it is an important subject to provide a digital programmable control for making the timing adjusting easier.
In view of the foregoing, the invention is to provide a digital programmable control for making the timing adjusting easier
To achieve the above, this invention discloses a driving-control device of a backlight module. The backlight module firstly receives a first digital burst signal. The driving-control device includes a start signal generating unit, a counter unit, a memory unit, a comparator unit and a driving unit. The start signal generating unit generates a digital start signal on receiving the first digital burst signal. The counter unit is electrically connected to the start signal generating unit and starts counting to generate a counting value whenever the start signal is generated. The memory unit stores at least one target counting value. The comparator unit is electrically connected to the counter unit and the memory unit and generates triggering signals whenever the counter value matches the target counting value. The driving unit is electrically connected to the comparator unit and outputs sequentially delayed driving signals on receiving the triggering signal.
To achieve the above, this invention also discloses a backlight driving-control method that includes the following steps of: generating a digital start signal on receiving a first digital burst signal, activating a counter unit to count so as to generate a counting value on receiving the digital start signal, comparing the counter value with at least one target counting value to generate at least one triggering signal, and outputting sequentially delayed driving signals on receiving the triggering signal.
As mentioned above, the driving-control device and the method of the backlight module of the invention have the following advantages. The comparator unit is utilized to compare the counting values generated by the counter unit with the target counting value stored in the memory unit to generate the sequentially delayed driving signals. Thus, when the light emitting units of the backlight module are driven by the sequentially delayed driving signals, the light emitting units can be sequentially lighted so that the light emitting units alternately light on and off. In other words, the impulse-type display may be simulated using the simple digital circuit design in accordance with the driving-control device and the method of the backlight module of the invention, and the blurring phenomenon may be reduced.
The invention will become more fully understood from the detailed description and accompanying drawings, which are given for illustration only, and thus are not limitative of the present invention, and wherein:
The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
Referring to
In this embodiment, the start signal generating unit 21 generates the digital start signal Ss1 on receiving a start triggering edge Ed1 of the first digital burst signal Bs1 (see
The counter unit 22 is electrically connected to the start signal generating unit 21, and starts to count on receiving the digital start signal Ss1 for generating counting values Cv. If the counter unit 22 is a 4-bit counter, it may count from 0000 to 1111. If the counter unit 22 is a 2-bit counter, it may count from 00 to 11. In this embodiment, the 2-bit counter is illustrated as an example. In addition, the counting unit 22 also starts to count after receiving the digital end signal Ss2. Herein, it is to be noted that the counting unit 22 may also be implemented by a timer.
The memory unit 23 stores at least one target counting value TCv. If the counter unit 22 is a 4-bit counter, the target counting value TCv may range from 0000 to 1111. If the counter unit 22 is a 2-bit counter, the target counting value TCv may range from 00 to 11.
The comparator unit 24 is electrically connected to the counter unit 22 and the memory unit 23. Whenever the counting value Cv matches the target counting value TCv, the comparator unit 24 generates a triggering signal Tr. In this embodiment, the counter unit 22 will be reset after the triggering signal Tr is generated. That is, after the counter unit 22 receives the triggering signal Tr outputted from the comparator unit 24, it starts to count again from 00. In this embodiment, six light emitting units 3 are illustrated. Hence, there are six activating triggering signals Tr1 to Tr6 and six de-activating triggering signals Tr7 to Tr12.
The driving unit 25 is electrically connected to the comparator unit 24 and outputs the sequentially delayed driving signals Ps on receiving the triggering signals Tr. Herein, a time delay exists between subsequent two sequentially delayed driving signals. The driving unit 25 sequentially outputs six delayed driving signals Ps1 to Ps6 for respectively driving those six light emitting units 3 so that the light emitting units 3 turn on and off alternately.
The driving unit 25 activates the delayed driving signal Ps1 on receiving the activating triggering signal Tr1. Similarly, on receiving the activating triggering signals Tr2 to Tr6, it activates delayed driving signals Ps2 to Ps6. Then, the driving unit 25 de-activates the delayed driving signal Ps1 on receiving the de-activating triggering signal Tr7. Similarly, on receiving the de-activating triggering signals Tr8 to Tr12 it de-activates the delayed driving signals Ps2 to Ps6.
Referring again to
As shown in
As shown in
Referring to
In step S01, a digital start signal is generated on receiving a first digital burst signal. Step S02 is to start counting to generate a counting value on receiving the digital start signal. In step S03, the counting value is compared with at least one target counting value TCv to generate a triggering signal. In step S04, sequentially delayed driving signals are outputted on receiving the triggering signal.
The detailed driving-control method and variations thereof have been described in the above-mentioned embodiments, so detailed descriptions thereof will be omitted.
Hereinafter, a summary of this work is given. To improve LCD picture quality, a sequential flashing driving control and method is developed in this invention. It includes a counter unit, a comparator unit, a memory unit and a driving unit. The counter unit receives a triggering signal and starts counting. The memory unit stores at least one target counting value. The comparator unit compares the counting value of the counter unit with the target counting value stored in the memory unit. Once these two values matching each other, a sequentially delayed driving signal will be generated. The counter unit can be reset and re-triggered multiple times to generate a group of sequentially delayed driving signals. These sequentially delayed driving signals drive the light emitting units of the backlight module. Therefore, the light emitting units can be sequentially turned on. In this way, LCD motion picture quality can be improved by turning its holding-type display characteristic into CRT-like impulse-type display. Still in this way, since the light emitting units are turned on alternately, a power-saving scheme can be designed using the sequential flashing technique disclosed in this invention.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 95132244 A | Aug 2006 | TW | national |
| 96130724 A | Aug 2007 | TW | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20060170452 | Benavides et al. | Aug 2006 | A1 |
| 20070257869 | Huang et al. | Nov 2007 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20080055233 A1 | Mar 2008 | US |
