Patent Publication Number: US-2010117950-A1

Title: Cascade sequential bus structure

Description:
FIELD OF THE INVENTION 
     The present invention relates to an image bus structure for an LCD system, particularly to an image bus structure for an assembled LCD billboard. 
     BACKGROUND OF THE INVENTION 
     Refer to  FIG. 1  and  FIG. 2 . In a conventional assembled LCD (Liquid Crystal Display) billboard using parallel buses, the drivers are parallel connected. Each LCD player has an LCD driver  1 . The LCD driver  1  is connected to an image data bus  2 , a control bus  3  and an image register  4 , and the LCD driver  1  sends out image signals via a display signal cable  5 . The image data bus  2  and the control bus  3  respectively output the required image information and enable signals to the image register  4 , and then the LCD drivers  1  drive the assembled LCD billboard to present the images via the display signal cables  5 . Refer to  FIG. 2 . Each LCD driver  1  needs a signal cable  6  and an enable signal cable  7  to connect with the image data bus  2  and the control bus  3 . Therefore, the wiring cables of the conventional assembled LCD not only increase the material cost and the output load but also inconvenience flexibly varying the dimensions of the assembled LCD billboard. 
     SUMMARY OF THE INVENTION 
     The primary objective of the present invention is to decrease the cables used in wiring an assembled LCD billboard and facilitate flexibly constructing different-size assembled LCD billboards. 
     The present invention proposes a cascade sequential bus structure used to provide required image data for an assembled LCD billboard. The assembled LCD billboard comprises a plurality of LCD drivers. The cascade sequential bus structure of the present invention comprises a plurality of image data buses corresponding to the plurality of LCD drivers. The image data bus includes an one-way output port, an one-way input port, and an one-way image register with two ends thereof respectively coupled to the output port and the input port. The image register connects with the LCD driver. The plurality of image data buses is cascaded via using a plurality of cascading signal cables to connect the output port of one image data bus to the input port of another image data bus. After the input port receives image data from the preceding stage, the image data is transmitted to the LCD driver and the output port via the image register. The image data is sequentially transposed in a first-in-first-out way from the output port of a front-stage image data bus to the input port of a rear-stage image data bus. The successive transposition of image data makes all the image data buses able to receive the image data. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram schematically showing the conventional control structure of an assembled LCD billboard; 
         FIG. 2  is a diagram schematically showing the conventional control signal connection of a conventional assembled LCD billboard; 
         FIG. 3  is a diagram schematically showing an image data bus according to one embodiment of the present invention; 
         FIG. 4  is a diagram schematically showing the control signal connection of an assembled LCD billboard according to one embodiment of the present invention; 
         FIG. 5  is a diagram schematically showing an image data bus according to another embodiment of the present invention; and 
         FIG. 6  is a diagram schematically showing the control signal connection of an assembled LCD billboard according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Below, the technical contents of the present invention are described in detail in cooperation with the drawings. 
     Refer to  FIG. 3  and  FIG. 4 . The present invention discloses a cascade sequential bus structure used to provide required image data for an assembled LCD billboard (not shown in the drawings). The assembled LCD billboard comprises a plurality of LCD drivers  10 . The LCD drivers  10  provide images for the assembled LCD billboard via display signal cables  11 . 
     The cascade sequential bus structure of the present invention comprises a plurality of image data buses  20  each corresponding to one LCD driver  10 . Each image data bus  20  provides image data for the LCD driver  10  connected thereto. Each image data bus  20  includes an one-way input port  21 , an one-way output port  22 , and an one-way image register  23  with two ends thereof respectively coupled to the output port  22  and the input port  21 . The image register  23  connects with the LCD driver  10 . The plurality of image data buses  20  is cascaded via using a plurality of cascading signal cables  15  to connect the output port  22  of one image data bus  20  to the input port  21  of another image data bus  20 . 
     The present invention also has a plurality of enable signal cables  30  providing enable signals. The enable signal cables  30  are respectively connected to the input ports  21  and the output ports  22  of the image data buses  20 . After the input port  21  receives image data and when the enable signal cable  30  provides the enable signal, the image data will be transmitted to the LCD driver  10  via the image register  23 , wherein the latest piece of image data is stored into the image register  23 , and the first piece of image data is pushed out of the image register  23  to the output port  22 . In other words, the image data is sequentially transposed in a first-in-first-out way, whereby the image data is transferred from the output port  22  of the front-stage image data bus  20  to the input port  21  of the rear-stage image data bus  20 . 
     The image data bus  20  also has a signal transmission cable  40 . The signal transmission cable  40  connects the input port  21  and the output port  22 . When the enable signal cable  30  does not provide the enable signal, the signal transmission cable  40  can directly transmit an identical piece of image data from the input port  21  to the output port  22 . Thereby, the identical image data can be transmitted faster, and the picture of the assembled LCD billboard cab be reset rapidly. Further, the image data bus  20  may also have a control-data register (not shown in the drawings) providing the enable signal. 
     Refer to  FIG. 5  and  FIG. 6 . The present invention may also have a plurality of directional signal cables  50  providing directional signals. The directional signal cables  50  are respectively connected to the input ports  21 A and the output ports  22 A of the image data buses  20 A. In this embodiment, the input port  21 A, output port  22 A, image register  23 A and cascading signal cable  15 A of the image data bus  20 A are all two-way elements, and the directional signal cable  50  provides the directional signal to control the transmission direction of image data. Further, the image data bus  20 A may also have a control-data register (not shown in the drawings) providing the directional signal. 
     As described above, the present invention transmits the image data to all the image data buses  20  with a transposition method. Each LCD driver  10  selects the corresponding portion of the image data to play, and all the LCD drivers  10  cooperate to present the whole image. The present invention can facilitate flexibly constructing different-size assembled LCD billboards. Further, the present invention can simplify the wiring of an assembled LCD billboard, greatly reduce the cables used in an assembled LCD billboard, and effectively lower the fabrication cost thereof.