Abstract:
A display method capable of displaying motion images includes displaying a first image, displaying a white or a gray image after displaying the first image, and displaying a second image subsequent to the first image after displaying the white image or the gray image using a liquid display panel. The method improves the display quality of moving images and the visual brightness of the liquid display panel by inserting white or gray images in order to reduce the frame delay of the liquid display panel.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention is a method of displaying for a liquid crystal display, and in particular, a method of displaying moving images on a liquid crystal panel.  
         [0003]     2. Description of the Prior Art  
         [0004]     Due to the fact that liquid crystal display devices are thin, light, use little power and output little radiation, they are used in various portable applications such as personal digital assistants (PDAs), digital cameras and camcorders, and are replacing conventional cathode ray tube (CRT) displays. However, the liquid crystal display device has its downside. When switching images, it is required to twist the orientation of liquid crystal molecules because of the limitations of liquid crystal molecules. Thus there is a delay in image display, and this is particularly obvious when the image being displayed is a moving image.  
         [0005]     The most effective way to eliminate the delay effect in image displaying on liquid crystal display devices is to increase the response time of liquid crystal materials. However, the liquid crystal material has a limitation of its response time; therefore, in general cases, the black image insertion technique is used. The technique inserts a black image in between each frame period, producing a fast pulse modulation effect similar to what the CRT does. Human brains filter such flickers and automatically generate a medium image, hence minimizing the effect of image delay.  
         [0006]     Please refer to  FIG. 1 .  FIG. 1  explains a method of the prior art, which solves the image delay phenomenon of a liquid crystal display device by inserting black images. In the figure, images P 1  to P n  represent the images displayed at time T 1  to T n  respectively on a liquid crystal display panel of a liquid crystal display device. Images B 1  to B n  are black images, while the time period between the two sequential times of T 1  to T n  defines frame periods F 1  to F n . In order to minimize the image delay phenomenon, the solution provided by the prior art is to insert a black image between a normal display image of a frame period and a normal display image of the next frame period. The first step is to divide each of the frame periods F 1  to F n  into two sub-frame periods F 1a  to F na  and F 1b  to F nb , where the sub-frame periods F 1a  to F na  start at times T 1  to T n  and the sub-frame periods F 1b  to F nb  start at times T 1 ′ to T n ′ respectively. Then, normal display images P 1  to P n  between sub-frame periods F 1a  to F na  of frame periods F 1  to F n , are displayed and black images B 1  to B n  between sub-frame periods F 1b  to F nb  of frame periods F 1  to F n  are displayed.  
         [0007]     The method of the prior art represented by  FIG. 1  is able to minimize the image delay phenomenon; nevertheless it reduces the quality of the visual performance of luminance of the liquid crystal display panel. This is because every frame period is required to be divided into sub-frame periods and one of the sub-frame periods is used to display the black image.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention provides a method of displaying a moving image on a liquid crystal display panel comprising the liquid crystal display panel displaying a first image; then the liquid crystal display panel displaying a white image or a gray image after displaying the first image; the liquid crystal display panel displaying a second image subsequent to the first image after displaying the white image or the gray image.  
         [0009]     The present invention also provides a method of displaying moving images comprising providing a moving image formed by a plurality of sequential frames, any two sequential frames of the plurality of sequential frames being separated by a first fixed time interval; and providing a plurality of white images or gray images alternating with the plurality of sequential frames, any two sequential white or gray images of the plurality of white images or gray images being separated by a second fixed time interval.  
         [0010]     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. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  explains a method of the prior art is to minimize the image delay phenomenon by inserting black images.  
         [0012]      FIG. 2  explains a first embodiment of the present invention is to minimize the image delay phenomenon by inserting white images.  
         [0013]      FIG. 3  is a block diagram of a liquid crystal display device of the present invention.  
         [0014]      FIG. 4  is a diagram of the liquid crystal panel displaying normal images.  
         [0015]      FIG. 5  is a diagram of the liquid crystal panel displaying white images.  
         [0016]      FIG. 6  explains a second embodiment of the present invention is to minimize the image delay phenomenon by inserting white images.  
         [0017]      FIG. 7  explains a third embodiment of the present invention is to minimize the image delay phenomenon by inserting white images.  
         [0018]      FIG. 8  explains a fourth embodiment of the present invention is to minimize the image delay phenomenon by inserting gray images.  
         [0019]      FIG. 9  explains a fifth embodiment of the present invention is to minimize the image delay phenomenon by inserting gray images.  
         [0020]      FIG. 10  explains a sixth embodiment of the present invention is to minimize the image delay phenomenon by inserting gray images. 
     
    
     DETAILED DESCRIPTION  
       [0021]     Please refer to  FIG. 2 , which explains a first embodiment of the present invention, which is to solve the image delay phenomenon on liquid crystal display devices using a white image insertion technique. In  FIG. 2 , images P 1  to P n  represents the images displayed by a liquid crystal display device at time T 1  to T n ; images W 1  to W n  are white images; and time intervals between each of the two sequential times T 1  to T n  are defined as frame periods F 1  to F n . In order to minimize the image delay phenomenon, the solution provided by the first practice is to insert a white image between a normal display image of a frame period and a normal display image of the next frame period. The first step is to divide each of the frame periods F 1  to F n  into two sub-frame periods F 1a  to F na  and F 1b  to F nb , where the sub-frame periods F 1a  to F na  start at times T 1  to T n  and the sub-frame periods F 1b  to F nb  start at times T 1 ′ to T n ′ respectively. Then the liquid crystal display panel displays normal display images P 1  to P n  between sub-frame periods F 1a  to F na  of frame periods F 1  to F n , and displays white images W 1  to W n  between sub-frame periods F 1b  to F nb  of frame periods F 1  to F n . The inserted white images W 1  to W n  not only minimize the image delay phenomenon but retain the quality of vision performance of the luminance of the liquid crystal display panel.  
         [0022]     In the first embodiment of the present invention, images P 1  to P n  can be sequential images of a moving image. The time intervals between each of the two sequential images P 1  to P n  can be equal to or longer than the time intervals between each of the two sequential white images W 1  to W n , for example: F 1 ≧(F 1b +F 2a ).  
         [0023]     Please refer to  FIG. 3 .  FIG. 3  is a block diagram of a liquid crystal display device  30  of the present invention. The liquid crystal display device comprises a liquid crystal display panel  40 , a gate driver  31 , a source driver  32 , a gamma circuit  34 , a timing controller  36  and a DC-DC converter  38 . The operation of the liquid crystal display device  30  is well known by people in the field, therefore description regarding it is not going to be repeated here. The present invention using the white image insertion method to minimize the image delay phenomenon includes using the timing controller  36  to control data output of each frame period to display normal display images P 1  to P n  between sub-frame periods F 1a  to F na  of frame periods F 1  to F n , and displaying white images W 1  to W n  between sub-frame periods F 1b  to F nb  of frame periods F 1  to F n .  
         [0024]     Please refer to  FIG. 4  and  FIG. 5 .  FIG. 4  shows the liquid crystal panel  40  of the liquid crystal display device  30  displaying normal images; whereas  FIG. 5  shows the liquid crystal panel  40  of the liquid crystal display device  30  displaying white images. The liquid crystal display panel  40  comprises a plurality of parallel data lines D 1  to D m  and a plurality of parallel scanning lines S 1  to S n . The data lines D 1  to D m  and scanning lines S 1  to S n  interconnect with each other to form a pixel matrix. There are thin film transistors acting as switches SW 1  to SW n , liquid crystal capacitors C LC11  to C LCnm  and storage capacitor C s1  to C snm  electronic components and a power source C com  to V cs  in a pixel matrix for each pixel. Data lines D 1  to D m  and scanning lines S 1  to S n  are coupled to the source driver  32  and the gate driver  31  respectively.  
         [0025]     In the sub-frame periods F 1a  to F na  of the frame periods F 1  to F n , the liquid crystal display device  30  receives signals corresponding to the images P 1  to P n . By the gate driver  31  opening the TFT switches of writing data into pixels, and the source driver  32  converting the received image information to corresponding data line voltages X 1  to X m , the data line voltage X 1  to X m  are able to be pushed to the opened pixel through data line D 1  to D m . As shown in  FIG. 4 , the images P 1  to P n  are therefore displayed in the sub-frame periods F 1a  to F na  of the frame periods F 1  to F n .  
         [0026]     In the sub-frame periods F 1b  to F nb  of the frame periods F 1  to F n , the liquid crystal display device  30  firstly opens the TFT switches of each pixel through the gate driver  31 , then pushes the data line voltages Y 1  to Y m , which is corresponding to information of white images, to the opened pixel through data lines D 1  to D m . As shown in  FIG. 5 , the white images W 1  to W n  are therefore displayed in the sub-frame periods F 1b  to F nb  of the frame periods F 1  to F n .  
         [0027]     In the first embodiment of the present invention, a white image is inserted in between a normal image display of a frame period and a normal image display of the next frame period. However, the present invention is also able to insert a white image between a predetermined number of frame periods. Please refer to  FIG. 6 , which explains a second embodiment of the present invention. The second embodiment of the present invention is to minimize the image delay phenomenon by inserting white images. In  FIG. 6 , images P 1  to P n  represent the images displayed by a liquid crystal display device on a liquid crystal display panel at time T 1  to T 2n+1 ; images W 1  to W n  are white images; and time intervals between each of the two sequential times T 1  to T 2n+1  are defined as frame periods F 1  to F 2n . In order to minimize the image delay phenomenon, the solution provided by the second embodiment is to insert a white image between a normal display image of a frame period and a normal display image of the next frame period. The first step is to divide each of the frame periods F 1  to F 2n+1  into two sub-frame periods F 2a  to F 2b , F 4a  to F 4a , . . . and F 2na  to F 2nb . The sub-frame periods F 2a , F 4a , . . . , and F 2na  start at times T 2 , T 4 , . . . , and T 2n , whereas the sub-frame periods F 2b  to F 2nb  start at times T 2 ′, T 4 ′, . . . , and T 2n ′ respectively. Then, the liquid crystal display panel displays normal display images P 1  to P n  between sub-frame periods F 1a  to F na  of frame periods F 1  to F n , and displays white images W 1  to W n  between sub-frame periods F 1b  to F nb  of frame periods F 1  to F n . Thereafter the liquid crystal display panel displays normal display images P 1 , P 3 , . . . , P 2n+1  between odd frame periods F 1 , F 3 , . . . respectively, and displays normal display images P 2 , P 4 , . . . , P 2n  between even frame periods F 2a , F 4a , . . . , F 2na  respectively, while displaying white images W 1  to W n  between the sub-frame periods F 2b , F 4b , . . . , F 2nb  of the even frame periods. The inserted white images W 1  to W n  not only minimize the image delay phenomenon but also retain the quality of vision performance of the luminance of the liquid crystal display panel.  
         [0028]     In the first and the second embodiments of the present invention, a white image is inserted in between a normal display image of a frame period and a normal display image of the next frame period, or in a predetermined number of frame periods. However, the present invention can also insert a plurality of white images instead. Please refer to  FIG. 7 , which explains a third embodiment of the present invention which is to solve the image delay phenomenon on liquid crystal display devices with a white image insertion technique. In  FIG. 7 , images P 1  to P n  represent the images displayed by a liquid crystal display device at time T 1  to T n ; time intervals between each of the two sequential times T 1  to T n  are defined as frame periods F 1  to F n ; images WI 1  to WI n  are images each containing two white pictures; time intervals between two sequential white images are represented by A 1  to A n  and A 1  to A n  and can have equal values. Therefore, the inserted white images WI 1  to WI n  minimize the image delay phenomenon without reducing the quality of vision performance of the luminance of the liquid crystal display panel.  
         [0029]     In a third embodiment of the present invention, images P 1  to P n  can be sequential images of a moving image. The time intervals between each of the two sequential images P 1  to P n  can be equal to or larger than the time intervals between each of the two sequential white images W 1  to W n , for example: F 1 ≧(F 1b +F 2a ). The white images WI 1  to WI n  can comprise two or more white pictures, and the time interval between two sequential white pictures is smaller than the time interval between two sequential white images. For example, A 1 &lt;(F 1b +F 2a ).  
         [0030]     Please refer to  FIG. 8 , which explains a fourth embodiment of the present invention, which is to solve the image delay phenomenon on liquid crystal display devices with a white/gray insertion technique. In  FIG. 8 , images P 1  to P n  represent the images displayed by a liquid crystal display device at time T 1  to T n ; images G 1  to G n  are gray images; time intervals between each of the two sequential times T 1  to T n  are defined as frame periods F 1  to F n . The fourth embodiment of the present invention is different from the first embodiment as the fourth embodiment inserts a gray image in between a normal image display of a frame period and a normal image display of the next frame period. The first step is to divide each of the frame periods F 1  to F n  into two sub-frame periods F 1a  to F na  and F 1b  to F nb , where the sub-frame periods F 1a  to F na  start at times T 1  to T n  and the sub-frame periods F 1b  to F nb  start at times T 1 ′ to T n ′ respectively. Then the liquid crystal display panel displays normal display images P 1  to P n  between sub-frame periods F 1a  to F na  of frame periods F 1  to F n , and displays gray images G 1  to G n  between sub-frame periods F 1b  to F nb  of frame periods F 1  to F n . Therefore, the inserted gray images G 1  to G n  minimize the image delay phenomenon without reducing the quality of vision performance of the luminance of the liquid crystal display panel.  
         [0031]     Please refer to  FIG. 9 , which explains a fifth embodiment of the present invention, which is to solve the image delay phenomenon on liquid crystal display devices with a white/gray insertion technique. The fifth embodiment of the present invention is different from the second embodiment as the fifth embodiment inserts a gray image in between a normal image display of a frame period and a normal image display of the next frame period. In  FIG. 9 , images P 1  to P n  represent the images displayed by a liquid crystal display device on a liquid crystal display panel at time T 1  to T 2n+1 ; images G 1  to G n  are gray images; and time intervals between each of the two sequential times T 1  to T 2n+1  are defined as frame periods F 1  to F 2n . The first step is to divide each of the frame periods F 1  to F 2n+1  into two sub-frame periods F 2a  to F 2b , F 4a  to F 4a , . . . and F 2na  to F 2nb . The sub-frame periods F 2a , F 4a , . . . and F 2na  start at times T 2 , T 4 , . . . , and T 2n , whereas the sub-frame periods F 2b  to F 2nb  start at times T 2 ′, T 4 ′, . . . , and T 2n ′ respectively. Then the liquid crystal display panel displays normal display images P 1  to P n  between sub-frame periods F 1a  to F na  of frame periods F 1  to F n , and displays gray images G 1  to G n  between sub-frame periods F 1b  to F nb  of frame periods F 1  to F n . Thereafter the liquid crystal display panel displays normal display images P 1 , P 3 , . . . , P 2n+1  between odd frame periods F 1 , F 3 , . . . respectively, and displays normal display images P 2 , P 4 , . . . , P 2n  between even frame periods F 2a , F 4a , . . . , F 2na  respectively, while displaying gray images G 1  to G n  between the sub-frame periods F 2b , F 4b , . . . , F 2nb  of the even frame periods. Therefore, the inserted gray images G 1  to G n  minimize the image delay phenomenon without reducing the quality of vision performance of the luminance of the liquid crystal display panel.  
         [0032]     Please refer to  FIG. 10 , which explains a sixth embodiment of the present invention, which is to solve the image delay phenomenon on liquid crystal display devices with a white/gray insertion technique. The sixth embodiment of the present invention is different from the third embodiment as the sixth embodiment inserts a gray image in between a normal image display of a frame period and a normal image display of the next frame period. In  FIG. 10 , images P 1  to P n  represent the images displayed by a liquid crystal display device at time T 1  to T n ; time intervals between each of two sequential times T 1  to T n  are defined as frame periods F 1  to F n ; images GI 1  to GI n  are images each containing two gray pictures; and time intervals between two sequential gray images are represented by A 1  to A n  and A 1  to A n  and can have equal values. Therefore, the inserted white images GI 1  to GI n  minimize the image delay phenomenon without reducing the quality of vision performance of the luminance of the liquid crystal display panel.  
         [0033]     In addition, in the first to the sixth embodiments of the present invention, the two sub-frame periods of the same frame period can have equal lengths or different lengths.  
         [0034]     The prior art minimizes the image delay phenomenon by inserting black images and reducing the luminance of liquid crystal display devices and hence affecting the display quality. In comparison to the prior art, the present invention minimizes the image delay phenomenon by inserting white images or gray images. This significantly improves the quality of displaying moving images on liquid crystal display devices without reducing the quality of vision performance of the luminance of the liquid crystal display panel.  
         [0035]     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. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.