Patent Application
20100039359
1. Field of Invention
The present invention relates to an adjustment circuit and an adjustment method thereof, especially to an adjustment circuit for color sequential liquid crystal displays and an adjustment method thereof.
2. Description of Related Art
Nowadays due to advanced technology, various new information products are developed and promoted to meet people's requirements. The conventional display device has shortages of large volume, high power consumption and high radiation dose while the liquid crystal display (LCD) features on compact volume, light weight, low radiation dose and low power consumption. Thus the conventional display device is replaced by the LCD which has become a main stream of a current display market. In order to make the crystal liquid displays really have features above mentioned, a high performance light-source is required to LCD design. The LCD itself can't emit light, so that when the device is under insufficient lighting environment, a light-source is required. For example, LCD on watches uses a mini-lamp as a light-source. Car meters or office automation terminals requires a light-source on the back so that the displayed images get more vivid. These laminar light-sources used on the rear side of the LCDs are called back lights.
Conventional LCD uses color filters to filter light so as to show the color of a pixel formed by three primary colors. To create a color image, there are three subpixels in each pixel-red, green and blue, respectively corresponding to red, green and blue color filters. Due to persistence of vision, the human eye receives red, green and blue light through the color filters and perceives pixel color. The light transmission of the LCD display and single pixel (dot) size are limited by the color filter. Thus display quality of the LCD is affected by the color filter.
In order to solve the above mentioned problem, a color sequential LCD has been developed. In the color sequential display, three primary colors of each pixel are displayed sequentially. A frame is decomposed into red, green, and blue fields displayed in successively. The three fields are illuminated by the red, green, and blue backlight accordingly. Relying on the human vision system, the successive images are fused into a color image. Thus the sequential display includes no color filter. Moreover, in contrast to pixel size of the LCD with color filter, the pixel size of the sequential display is smaller. Therefore, the color sequential display has higher resolution with lower cost.
A conventional color sequential CLD only uses lighting units such as light emitting diode with three primary colors-red(R), green(G) and blue(B) as backlights. Lights from the three primary color (RGB, tricolor) backlights are mixed to form a color of a single pixel. The mixing of three primary colors only generates eight basic colors so that each pixel has eight possible colors. Thus the use of the colors on the conventional color sequential LCD is quite monotonous. Moreover, when images are shown on a conventional sequential LCD by color sequential operation, the brightness is insufficient. Thus the quality of color images displayed on the color sequential LCD is reduced.
Therefore, there is a need to provide an adjustment circuit for color sequential liquid crystal displays and an adjustment method thereof that overcome the shortcoming of monotonous colors of conventional color sequential LCD and solve the problems mentioned above.
It is therefore a primary object of the present invention to provide an adjustment circuit for color sequential liquid crystal displays and a method thereof. The colors displayed by the color sequential LCD are adjusted according to at least one adjusted-color backlight generated behind the tricolor backlights. Thus overall number of colors that can be rendered is increased and the display brightness is also improved.
In order to the achieve object, the present invention provides an adjustment circuit for color sequential liquid crystal displays and an adjustment method thereof. The adjustment circuit includes a light-source driving circuit and a display driver circuit. The light-source driving circuit generates a plurality of driving signals and the display driver generates a display driving signal. The driving signals are used to control the color sequential LCD for generating a plurality of three primary color (RGB, tricolor) backlights and at least one adjusted-color backlight. According to the display driving signal, the tricolor backlights and the adjusted-color backlight, the color sequential LCD displays a frame. The method of the present invention adjusts colors by the adjusted-color backlight for further adjustment of colors and brightness of the frames. The adjusted-color backlight is generated behind one of the tricolor backlight. Moreover, according to colors of each frame, the light-source driving circuit adjusts time of the color sequential LCD to generate the adjusted-color backlight for adjusting colors displayed by the frame so as to further improve color quality of displayed images.
The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed descriptions of the preferred embodiments and the accompanying drawings, wherein
Refer to
The display driving circuit is for generating a display driving signal which includes a data signal and a scan signal. The data driving circuit 12 of the display driving circuit is for generating the data signal and sending the data signal to the display module 24 of the display panel 20. The data signal includes a plurality of data pulses. The scan driving circuit 14 of the display driving circuit is used to generate the scan signal and send the scan signal to the display module 24 of the display panel 20.
Based on the above description, according to the display driving signal, and in combination with sequential tricolor (RGB) backlights as well as mixing-color backlight generated by the backlight unit 22, the display panel 20 of the color sequential LCD displays a frame. Moreover, the light-source driving circuit 10 of the present invention can adjust time of the backlight unit 22 to generate adjusted-color backlight according to colors of different frames so as to modify colors shown by the display module 24.
Refer back to
Refer to
As to LEDR, it's a driving signal from the light-source driving circuit 10 to drive the backlight unit 22 generating the red backlight. LEDG represents a driving signal from the light-source driving circuit 10 to drive the backlight unit 22 generating the green backlight and LEDB is a driving signal from the light-source driving circuit 10 to drive the backlight unit 22 generating the blue backlight. These driving signals include a plurality of driving pulses 50. When these driving pulses 50 of driving signals LEDR, LEDG, LEDB are at high level, this means that the backlight unit 22 generates backlights of three primary colors (RGB, tricolor)—red backlight, green backlight and blue backlight. In this embodiment, the adjusted-color backlight is a white backlight that is generated behind each backlight. Thus when driving signals for tricolor backlight LEDR, LEDG, and LEDB are all at high level, the light-source driving circuit 10 uses this as a driving signal corresponding to generation of the adjusted-color backlight. Therefore, by increasing of the adjusted-color backlight behind each backlight, the present invention adjusts gray level of tricolor backlights so as to increase number of colors rendered and enhance display brightness on the display module 24.
Moreover, according to colors of the frame, the light-source driving circuit 10 adjusts pulse width of driving pulses of the driving signals corresponding to the adjusted-color backlights so as to modify gray level of colors. For example, the pulse width of the driving signal corresponding to the adjusted-color backlight is divided into eight equal parts so that the light-source driving circuit 10 adjusts pulse width of the driving pulses 50 of the driving signals LEDR, LEDG, and LEDB into 8 different widths. Thus the mixed color backlight has 8 different gray level patterns. The combinations of red backlight and white backlight include R+0/8 W, R+1/8W, R+2/8W, R+3/8W, R+4/8W, R+5/8W, R+6/8W, R+7/8W, and R+8/8W. The combinations of green backlight and white backlight include G+0/8 W, G+1/8W, G+2/8W, G+3/8W, G+4/8W, G|5/8W, G|6/8W, G|7/8W, and G|8/8W. The combinations of blue backlight and white backlight include B+0/8 W, B+1/8W, B+2/8W, B+3/8W, B+4/8W, B+5/8W, B+6/8W, B+7/8W, and B+8/8W.
According to the above description, the present invention dramatically increases number of colors of the pixel 30 by adjustment of gray levels of the adjusted-color backlight. Due to nine color patterns of each tricolor backlight, there are 729 (9×9×9) colors represented by the pixel 30. Thus there are quite a lot colors available per each pixel and this is significantly better than conventional color sequential LCD.
Furthermore, when the light-source driving circuit 10 adjusts the pulse width of the driving pulses 50 of the driving signals LEDR, LEDG, and LEDB for adjusting generation time of the adjusted-color backlight, the data driving circuit 12 correspondingly adjusts the pulse width of data pulses 40 of the data signals SEG1, SEG2, SEG3 in accordance with the generation time of the adjusted-color backlight.
Refer to
In summary, an adjustment circuit for color sequential liquid crystal displays and an adjustment method thereof according to the present invention is provided. By control of the light-source driving circuit to generate a plurality of driving signals, the color sequential liquid crystal display generates a plurality of primary color backlights and at least one adjusted-color backlight according to the driving signals so as to adjust colors and brightness of the frames. Moreover, according to colors of the frames, the light-source driving circuit adjusts time of the color sequential LCD to generate the adjusted-color backlight so as to modify gray level of colors for increasing number of colors rendered.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative devices shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 097130865 | Aug 2008 | TW | national |
