Abstract:
A liquid crystal display (LCD) apparatus includes a backlight module and a LCD module. The backlight module has a plurality of individually drivable backlight regions. The LCD module has a plurality of display blocks, each of which corresponds to one of the backlight regions and is disposed on an optical path of light emitted from the corresponding backlight regions. A power regulating module is electrically connected to the backlight module and the LCD module for receiving image frame data and controlling light-emitting intensities of the backlight regions in accordance with the image frame data to be displayed by the corresponding display blocks. Each backlight regions has multiple light-emitting units for emitting light in different colors. Each display block has a plurality of pixels, and each of the pixels has multiple filter units. A transmitted spectrum of each of the light-emitting units of the backlight regions corresponds to transmitted spectrums of at least two filter units of each of the pixels in the respective display blocks.

Description:
[0001]    This application claims the benefit of Taiwan application Serial No. 96106840, filed Feb. 27, 2007, the entirety of which is incorporated herein by reference. 
         [0002]    This application is also related to Taiwan application Serial 95110050, filed Mar. 24, 2006, which corresponds to U.S. application Ser. No. 11/688,634, filed Mar. 20, 2007 and the entirety of which is incorporated herein by reference. 
       BACKGROUND 
       [0003]    1. Technical Field 
         [0004]    The disclosure relates to a display apparatus and a control method thereof, and, in particular, to a liquid crystal display (LCD) apparatus and an image control method thereof. 
         [0005]    2. Related Art 
         [0006]    Liquid crystal display (LCD) apparatuses have the advantages of low power consumption, low generated heat, lighted weight and non-radiative property, so that the LCDs have been used in various electronic products and gradually replaced the conventional cathode ray tube (CRT) display apparatus. 
         [0007]    However, because the LCD apparatus has a multi-layer structure, the light outputted from the backlight module must penetrate through many optical films and a liquid crystal layer, so that the problem of the optical loss is very serious. Usually, the light finally outputted from the surface of the liquid crystal panel is only equal to a small fraction of the light outputted from the backlight source. Therefore, the LCD apparatus usually has the problem of insufficient brightness. 
         [0008]    Regarding to this problem, a conventional solution is to add a white-light filter unit to the tricolor (RGB) filter unit in each pixel so that the light output amount of the white backlight is increased and the pixel brightness is increased.  FIG. 1  is a schematic illustration showing the comparison of characteristics according to the conventional method (solid line) and conventional improvement method (broken line), wherein each characteristic represents a relationship between the brightness and the color saturation. As shown in  FIG. 1 , the brightness of the pixel utilizing the conventional improvement method is significantly increased when the pixel displays the tricolor mixture. However, when the displayed light of the pixel is close to monochromatic light (i.e. red, green or blue light), the brightness of the pixel utilizing the conventional improvement method is inversely lower than that utilizing the conventional method. 
         [0009]    This is because the white backlight emitted from the white-light filter unit cannot become the gain for the displayed light when the displayed light approximates to monochromatic light. Inversely, the output amount of the monochromatic light is decreased because the area of the monochromatic filter unit is reduced. Thus, when the monochromatic light is being displayed, the brightness of the pixel utilizing the conventional improvement method is inversely lower than that utilizing the conventional method. Consequently, the brightness variation of the pixel utilizing the conventional improvement method is much greater than that utilizing the conventional method. 
         [0010]    Therefore, it is important to provide a LCD apparatus with the enhanced display brightness and stable brightness variation, and an image control method thereof. 
       SUMMARY 
       [0011]    In an embodiment, the invention provides a liquid crystal display (LCD) apparatus including a backlight module, an LCD module, and a power regulating module. The backlight module has a plurality of individually drivable backlight regions. The LCD module has a plurality of display blocks. Each of the display blocks corresponds to one of the backlight regions and is disposed on an optical path of light emitted from the corresponding backlight regions. The power regulating module is electrically connected to the backlight module and the LCD module for receiving image frame data and controlling light-emitting intensities of the backlight regions in accordance with the image frame data to be displayed by the corresponding display blocks. Each backlight regions has multiple light-emitting units for emitting light in different colors. Each display block has a plurality of pixels, and each of the pixels has multiple filter units. A transmitted spectrum of each of the light-emitting units of the backlight regions corresponds to transmitted spectrums of at least two filter units of each of the pixels in the respective display blocks. 
         [0012]    In a further embodiment, the invention also provides an image control method of a liquid crystal display (LCD) apparatus including a backlight module and a LCD module. The backlight module has a plurality of individually drivable backlight regions. The LCD module has a plurality of display blocks. Each of the display blocks corresponds to one of the backlight regions and is disposed on an optical path of light emitted from the corresponding backlight regions. Each backlight regions has multiple light-emitting units for emitting light in different colors. Each display block has a plurality of pixels, and each of the pixels has multiple filter units. A transmitted spectrum of each of the light-emitting units of the backlight regions corresponds to transmitted spectrums of at least two filter units of each of the pixels in the respective display blocks. The image control method includes receiving image frame data to be displayed by the display blocks; controlling light-emitting intensities of the backlight regions in accordance with the image frame data; and allowing light emitted from each of the light-emitting units of the backlight regions to pass through said at least two filter units of each of the pixels in the respective display blocks. 
         [0013]    Additional aspects and advantages of the disclosed embodiments are set forth in part in the description which follows, and in part are apparent from the description, or may be learned by practice of the disclosed embodiments. The aspects and advantages of the disclosed embodiments may also be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The embodiments of 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: 
           [0015]      FIG. 1  is a schematic illustration showing the comparison of characteristics according to the conventional method and conventional improvement method, wherein each characteristic represents a relationship between the brightness and the color saturation; 
           [0016]      FIG. 2  is schematic illustration showing a LCD apparatus according to an embodiment of the invention; 
           [0017]      FIGS. 3A and 3B  are schematic illustrations showing dividing aspects of the backlight regions of the LCD apparatus according to various embodiments of the invention; 
           [0018]      FIGS. 4A to 4C  are schematic illustrations showing arrangements of the filter units in the LCD apparatus according to various embodiments of the invention; 
           [0019]      FIG. 5  is a schematic block diagram showing the LCD apparatus according to an embodiment of the invention; 
           [0020]      FIG. 6  is a schematic illustration showing a characteristic, which represents a relationship between the brightness and the color saturation of the LCD apparatus according to embodiments of the invention; and 
           [0021]      FIG. 7  is a flow chart showing an image control method of the LCD apparatus according to a further embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0022]    The embodiments of the present invention will be apparent from the following detailed description, with reference to the accompanying drawings, wherein the same references relate to the same elements. 
         [0023]    Referring to  FIG. 2 , a liquid crystal display (LCD) apparatus  1  according to an embodiment of the invention includes a backlight module  11  and an LCD module  12 . 
         [0024]      FIGS. 3A and 3B  are schematic illustrations showing possible, exemplary dividing manners of backlight regions  111  of the backlight module  11 . The backlight module  11  is divided into nine regions in  FIG. 3A , while the backlight module  11  is divided into four regions in  FIG. 3B . However, the dividing manners of the backlight module  11  are not limited thereto and may be configured according to the preferential consideration of increasing the displayed brightness. 
         [0025]    As shown in  FIG. 2 , a first light-emitting unit  111   a , a second light-emitting unit  111   b  and a third light-emitting unit  111   c  emitting light of different colors are further disposed in each backlight region  111 . In this embodiment, the first light-emitting unit  111   a , the second light-emitting unit  111   b  and the third light-emitting unit  111   c  are respectively a red light-emitting diode (LED), a green LED and a blue LED. 
         [0026]    In order to prevent the light outputted from the backlight regions  111  from interfering with one another, an isolating partition  112  for isolating the backlight outputted from the backlight regions  111  is further disposed between the adjacent backlight regions  111 . In practice, the isolating partition  112  may be made of various materials according to the preferential consideration of the good light isolating effect. 
         [0027]    As shown in  FIG. 2 , the LCD module  12  is disposed adjacent to the backlight module  11  and has a plurality of display blocks  121 . Each display block  121  corresponds to one backlight region  111  and is disposed on optical paths of the red LED  111   a , the green LED  111   b  and the blue LED  111   c . The display block  121  also has a plurality of pixels  121   a , and each pixel  121   a  has a first filter unit CF 1 , a second filter unit CF 2 , a third filter unit CF 3  and an enhancing filter unit CF 4 . The first filter unit CF 1  is a red filter unit, so that only red light outputted from the red LED  111   a  can penetrate through the first filter unit CF 1 . The second filter unit CF 2  and the third filter unit CF 3  are respectively a green filter unit and a blue filter unit. Similarly, only green light outputted from the green LED  111   b  can penetrate through the green filter unit CF 2 , and only blue light outputted from the blue LED  111   c  can penetrate through the blue filter unit CF 3 . In addition, the enhancing filter unit CF 4  is a white-light filter unit, and the red light, green light and blue light can penetrate through the enhancing filter unit CF 4 . 
         [0028]    In addition, various arrangements of the filter units are depicted in  FIGS. 4A to 4C .  FIG. 4A  shows a filter composed of four rectangular filter units (CF 1  to CF 4 ) having the same area.  FIG. 4B  shows a filter composed of four square filter units (CF 1  to CF 4 ) having the same area. In  FIG. 4C , the rectangular filter units (CF 1  to CF 3 ), which are, respectively, red, green and blue filter units and have the same area, are disposed in a row, and three square white-light filter units CF 4  are respectively disposed at middle portions of the rectangular filter units (CF 1  to CF 3 ). To be noted, the arrangements of the filter units are not limited to this embodiment, and may be modified according to the preferential consideration of increasing the displayed brightness. 
         [0029]    As shown in  FIG. 5 , the LCD apparatus  1  may further include a power regulating module  13  electrically connected to the backlight module  11  and the LCD module  12 . The power regulating module  13  has a dividing unit  131  and a regulating unit  132  electrically connected to the dividing unit  131 . 
         [0030]    When one image frame data  2  is inputted to the power regulating module  13 , the dividing unit  131  divides the image frame data  2  into plural image frame data blocks  21  respectively corresponding to the backlight regions  111 . The regulating unit  132  receives at least one image frame data block  21 , finds the pixel with the largest transmission rate  22  (e.g., 100 on the 0-255 grey scale) in the image frame data block  21 , and adjusts the largest transmission rate  22  to the maximum value (e.g., 255). Therefore, a ratio (255/100) can be obtained. Next, the transmission rates  22  of the other pixels are adjusted, i.e., raised, according to the ratio, and a backlight voltage signal  23  of each of the light-emitting units ( 111   a  to  111   c ) of the backlight region  111  is also adjusted, i.e., reduced, according to the ratio. Then, the power regulating module  13  outputs the adjusted transmission rates  22  to the respective pixels  121   a  of the display block  121 , and outputs the adjusted backlight voltage signals  23  to drive the light-emitting units ( 111   a  to  111   c ) of the respective backlight region  111  to emit light. 
         [0031]      FIG. 6  is a schematic illustration showing a characteristic, which represents a relationship between the brightness and the color saturation of the LCD apparatus according to the above disclosed embodiment of the invention. Compared with the characteristics of  FIG. 1 , the brightness of embodiments of the invention has been improved in many aspects, and the brightness variation of embodiments of the invention is much more stable than that of the conventional improvement method. 
         [0032]    In addition, an image control method according to embodiments of the invention is applied to the LCD apparatuses of  FIGS. 2 to 5 . As shown in  FIG. 7 , the image control method includes the following procedures S 1  to S 5 . 
         [0033]    The procedure S 1  is an image inputting procedure, in which the LCD apparatus  1  sequentially receives image frame data  2 . 
         [0034]    The procedure S 2  is an image dividing procedure, in which the dividing unit  131  of the power regulating module  13  receives the image frame data  2 , and divides the image frame data  2  into plural image frame data blocks  21  each according to one of the backlight regions  111 . 
         [0035]    The procedure S 3  is a power regulating procedure, in which the regulating unit  132  raises a transmission rate of each pixel  121   a  in the display block  121  of the LCD module  12  according to a ratio, and reduces an average brightness of each backlight region  111  of the backlight module  11  according to the ratio. It is also within the scope of the present invention to reduces a transmission rate of each pixel  121   a  in the display block  121  of the LCD module  12  according to a ratio, and raises an average brightness of each backlight region  111  of the backlight module  11  according to the ratio. 
         [0036]    The procedure S 4  is a backlight module emitting procedure, in which the first light-emitting unit  111   a , the second light-emitting unit  111   b  and the third light-emitting unit  111   c  respectively emit first spectrum light, second spectrum light and third spectrum light according to the reduced average brightness at procedure S 3 . 
         [0037]    The procedure S 5  is a LCD module outputting procedure, in which the first spectrum light penetrates through the first filter unit CF 1  and the enhancing filter unit CF 4  of each pixel  121   a , the second spectrum light penetrates through the second filter unit CF 2  and the enhancing filter unit CF 4  of each pixel  121   a , and the third spectrum light penetrates through the third filter unit CF 3  and the enhancing filter unit CF 4  of each pixel  121   a  to create an image in conjunction with the LCD module  12  which is being driven according to the raised transmission rate. 
         [0038]    The image control method and the functions of each module have been mentioned in the above embodiment, so detailed descriptions thereof will be omitted. 
         [0039]    According to another embodiment of the invention, the white-light filter unit of the above-mentioned embodiment is replaced with a cyan filter unit, a magenta filter unit or a yellow filter unit. If the white-light filter unit is replaced with the yellow filter unit, the red light outputted from the red LED in the backlight region penetrates through the red filter unit and the yellow filter unit, and the green light outputted from the green LED in the backlight region penetrates through the green filter unit and the yellow filter unit. Accordingly, the transmissive areas of the red light and the green light are larger in this embodiment so that better brightness may be obtained. Similarly, the magenta filter unit may be selected to enhance the brightness of the red light and the blue light, and the cyan filter unit may be selected to enhance the brightness of the blue light and the green light. 
         [0040]    According to still another embodiment of the invention, the red filter unit, the green filter unit and the blue filter unit according to the above-mentioned embodiment are respectively replaced with a cyan filter unit, a magenta filter unit and a yellow filter unit, and the white-light filter unit is removed. In this embodiment, the red light outputted from the red LED in the backlight region penetrates through the magenta filter unit and the yellow filter unit, and the green light outputted from the green LED penetrates through the cyan filter unit and the yellow filter unit, and the blue light outputted from the blue LED penetrates through the cyan filter unit and the magenta filter unit. Compared with the above-mentioned embodiment, this embodiment may obtain the desired brightness with fewer filter units. 
         [0041]    According to yet still another embodiment of the invention, the red filter unit, the green filter unit and the blue filter unit according to the above-mentioned embodiment are respectively replaced with a cyan filter unit, a magenta filter unit and a yellow filter unit, while the white-light filter unit is kept. In this embodiment, the red light outputted from the red LED in the backlight region penetrates through the magenta filter unit, the yellow filter unit and the white-light filter unit, the green light outputted from the green LED penetrates through the cyan filter unit, the yellow filter unit and the white-light filter unit, and the blue light outputted from the blue LED penetrates through the cyan filter unit, the magenta filter unit and the white-light filter unit. Compared with the above-mentioned embodiment, this embodiment has larger transmissive areas for each color so that higher brightness may be obtained. 
         [0042]    In addition to the above-mentioned modifications, the functions of the modules and the image control methods are the same as those of the above-mentioned embodiment. So, detailed descriptions thereof are omitted. 
         [0043]    In summary, the backlight module is divided into different backlight regions so that the outputted backlight becomes more uniform in the LCD apparatus and the image control method thereof according to embodiments of the invention. In addition, the backlight sources with three colors (i.e. red, green and blue) in each backlight region are respectively controlled in accordance with image data. Thus, when one backlight region only needs one monochromatic light, such as red, green or blue light, only the monochromatic light source has to be turned on. Meanwhile, each pixel in the backlight region further has an enhancing filter unit, and the monochromatic light penetrates through both the corresponding color filter unit and the enhancing filter unit. Thus, the light emitted from the enhancing filter unit becomes the gain of the displayed brightness of the monochromatic light. 
         [0044]    Compared with the related art, embodiments of the invention add the enhancing filter unit and modifies the structure and arrangement of the backlight module. Thus, embodiments of the invention can enhance the displayed brightness more effectively so that the brightness variation becomes more stable. In addition, a power regulating module is utilized to enhance the transmission rate of each pixel and to decrease the light-emitting intensity of the respective backlight module. Thus, the power consumption of the backlight module can be reduced without decreasing the displayed brightness. 
         [0045]    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.