1. Field of the Invention
The invention relates in general to an addressing method of a color sequential display and more particularly to a frame-varying addressing method of a color sequential liquid crystal display (LCD).
2. Description of the Related Art
In recent years, the flat panel display (FPD) industry has been focused on developing liquid crystal displays (LCDs), especially on developing thin film transistor (TFT) LCDs, and hoping to replace the role of cathode ray tube (CRT) displays in video applications. Each pixel on a TFT LCD is provided with a switching transistor for enabling image data to be written into a panel of the display.
One way of displaying the TFT LCD is to use color sequential technology. A typical frame for displaying a color image is divided into three subframes for the three primary colors of red, green and blue, and each subframe is further divided into a subframe writing period and a subframe illumination period. To display the color image, the TFT LCD is first addressed line by line by display drivers to write image data of the corresponding primary color into the pixels during the corresponding subframe writing period, in the meanwhile, capacitors located at each pixel are charged to set the liquid crystals within the pixels to their light transmittive states for displaying appropriate gray values of the corresponding primary color. Then, during the subframe illumination period, light sources, such as light emitting diode (LEDs), are turned on to display the corresponding primary color component of the color image, such that these three primary color components can be compositely perceived as a full-color image. However, the color sequential display is likely to suffer spatial intensity variations due to insufficient response time, which may cause the bottom portion of the TFT LCD to appear dimmer.
Hence, there is a need to provide a novel addressing method to effectively eliminate the spatial intensity variations associated with the conventional color sequential display.
It is therefore an object of the invention to provide a novel frame-varying addressing method of a color sequential liquid crystal display for display of successive frames, so as to effectively minimize the spatial intensity variations associated with the conventional addressing method.
The invention achieves the above-identified object by providing a frame-varying addressing method of a color sequential liquid crystal display for display of successive frames. Each of the frames is composed of three subframes, and each of the subframes is composed of a plurality of scan lines. According to the frame-varying addressing method of the invention, the addressing sequence of scan lines for display of any frame or subframe is arranged in the same direction as those for display of its adjacent frames or subframes, and is selected to be different from those for display of its adjacent frames or subframes. Further, the addressing sequence of scan lines for the frame (subframe) and its adjacent frames (subframes) can be periodically or randomly selected, so as to effectively balance or greatly eliminate the spatial intensity variations due to inconsistent response times at different portions of the panel, which are associated with the conventional addressing method.
Other objects, features, and advantages of the invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings.
Conventionally, in each and every subframe, the pixels of the panel 170 are sequentially addressed line by line by gate drivers from top to bottom or from bottom to top. However, this will result in spatial intensity variations due to inconsistent pixel response time at different portions of the panel 170.
To eliminate the spatial intensity variations, this invention provides a novel frame-varying line addressing method, which periodically or randomly alters the position of the first scan line in successive frames or subframes. With this invention, the last scan line of the panel 170 in the successive frames or subframes will not necessarily be located at the same portion of the panel 170. Rather, the last scan line of the panel 170 in successive frames or subframes can be different in position, thus effectively balancing the spatial intensity variations due to inconsistent response time at different portions of the panel. Therefore, the spatial intensity variations can be balanced over the entire area of the panel 170.
For example, in the frame f(1), the addressing sequence of scan lines may start from line 1, which is indicated by SL, and continued with line 2, line 3 and line 4. In this case, the addressing sequence of scan lines for three subframes Sr(1), Sg(1) and Sb(1) of the frame f(1) also follow the same addressing sequence of scan lines as the frame (1). That is, the addressing sequence of scan lines for the red subframe Sr(1) having a period Tr follows the addressing sequence of lines 1, 2, 3 and 4; the line addressing sequence of scan lines for the green subframe Sg(1) having a period Tg follows the addressing sequence of lines 1,2, 3 and 4; and the addressing sequence of scan lines for the blue subframe Sb(1) having a period Tb follows the addressing sequence of lines 1, 2, 3 and 4.
Subsequently, in the following frame f(2), the addressing sequence of scan lines is arranged in the same direction of that for the frame f(1), and is selected to be different from that for the frame f(1). For example, the addressing sequence of scan lines may start from line 2, which is indicated by SL, and continued with line 3, line 4 and back to line 1. That is, the addressing sequence of scan lines for the red subframe Sr(2) having a period Tr follows the addressing sequence of lines 2, 3, 4 and 1; the addressing sequence of scan lines for the green subframe Sg(2) having a period Tg follows the addressing sequence of lines 2, 3, 4 and 1; and the addressing sequence of scan lines for the blue subframe Sb(2) having a period Tb follows the addressing sequence of lines 2, 3, 4 and 1.
Subsequently, in the following frame f(3), the addressing sequence of scan lines is arranged in the same direction as those for the frame f(1) and the frame f(2), and is selected to be different from those for the frame f(1) and the frame f(2). For example, the addressing sequence of scan lines may start from line 3, which is indicated by SL, and continue with line 4 and back to line 1 and line 2. That is, the addressing sequence of scan lines for the red subframe Sr(3) having a period Tr follows the addressing sequence of lines 3, 4, 1 and 2; the addressing sequence of scan lines for the green subframe Sg(3) having a period Tg follows the addressing sequence of lines 3, 4, 1 and 2; and the addressing sequence of scan lines for the blue subframe Sb(3) having a period Tb follows the addressing sequence of lines 3, 4, 1 and 2.
Finally, in the frame f(4), the addressing sequence of scan lines is arranged in the same direction as those for the frame f(1), the frame f(2) and the frame f(3), and is selected to be different from those of the frame f(1), the frame f(2) and the frame f(3). For example, the addressing sequence of scan lines may start from line 4, which is indicated by SL, and back to line 1, line 2 and line 3. That is, the addressing sequence of scan lines for the red subframe Sr(4) having a period Tr follows the addressing sequence of lines 4, 1, 2 and 3; the line addressing sequence for the green subframe Sg(4) having a period Tg follows the addressing sequence of lines 4, 1, 2 and 3; and the addressing sequence of scan lines for the blue subframe Sb(4) having a period Tb follows the addressing sequence of lines 4, 1, 2 and 3.
Thereafter, the addressing sequence of scan lines for successive frames may periodically repeat the addressing sequence of scan lines for the preceding frames. With this frame-varying addressing sequence, the spatial intensity variations due to inconsistent response times at different portions of the panels can be effectively balanced or greatly eliminated.
Although the invention has been described in accordance to a preferred embodiment, however, without departing from the spirit and scope of the claims, the invention may also encompass other modifications. For example, the addressing sequence of scan lines for each of the subframes within the same frame does not have to coincide with each others and can be selected to be different from each others. For instance, in the frame f(2), the addressing sequence of scan lines for the red subframe Sr(2) can be different from those for the green subframe Sg(2) and the blue subframe Sb(2), so as to further balance the inconsistent response times at different portions of the panel.
Also, the panel can be segmented into a plurality of units, with each of the units composing of a plurality of scan lines. In this case, the addressing sequence of units and the addressing sequence of scan lines within the units can also be periodically or randomly varied, so as to balance the spatial intensity variations due to inconsistent response times at different portions of the panel.
While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.
Number | Name | Date | Kind |
---|---|---|---|
4627004 | Cool et al. | Dec 1986 | A |
4897806 | Cook et al. | Jan 1990 | A |
4941040 | Pocock et al. | Jul 1990 | A |
5025400 | Cook et al. | Jun 1991 | A |
5144688 | Bovir et al. | Sep 1992 | A |
5233338 | Surguy | Aug 1993 | A |
5475420 | Buchin | Dec 1995 | A |
5563962 | Peters et al. | Oct 1996 | A |
5731802 | Aras et al. | Mar 1998 | A |
6057824 | Katakura et al. | May 2000 | A |
6249265 | Tajima et al. | Jun 2001 | B1 |
6476824 | Suzuki et al. | Nov 2002 | B1 |
6700562 | Knapp et al. | Mar 2004 | B1 |
6864900 | Wasserman et al. | Mar 2005 | B2 |
7102610 | Ludden | Sep 2006 | B2 |
20020047824 | Handschy et al. | Apr 2002 | A1 |
20020180742 | Hamid | Dec 2002 | A1 |
20030035123 | Ramanujan et al. | Feb 2003 | A1 |
20030076990 | Brand | Apr 2003 | A1 |
20030236458 | Hochman | Dec 2003 | A1 |
20040207592 | Ludden | Oct 2004 | A1 |
20040212632 | Inada et al. | Oct 2004 | A1 |
20050001812 | Amundson et al. | Jan 2005 | A1 |
20050104816 | Kimura et al. | May 2005 | A1 |
20050156839 | Webb | Jul 2005 | A1 |
20050168437 | Carl et al. | Aug 2005 | A1 |
20050225545 | Takatori et al. | Oct 2005 | A1 |
20050243176 | Wu et al. | Nov 2005 | A1 |
20050248553 | Feng et al. | Nov 2005 | A1 |
20060125748 | Yang et al. | Jun 2006 | A1 |
20060250336 | Wood | Nov 2006 | A1 |
20060280360 | Holub | Dec 2006 | A1 |
Number | Date | Country | |
---|---|---|---|
20060132405 A1 | Jun 2006 | US |