Patent Publication Number: US-2010110061-A1

Title: Local area image displaying system

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to image display technology, and more particularly to a local area image displaying system for a display device. 
     2. Description of the Related Art 
     The main stream of the liquid crystal displays (LCD) currently available in the market is thin-film-transistor (TFT) LCD driven in an active matrix fashion. A feature of the thin film transistor is that pixels are controlled in a manner similar to a large-scale integrated circuit constituted by silicon transistor electrodes made with thin film techniques. In other words, the electrodes are formed by lining up transistors, and each pixel is directly controlled by applying point-based pulses and can be controlled in a continuous manner. 
     However, the currently adopted techniques for displaying with a TFT-LCD is full screen displaying, together with variation of brightness realized through a backlight module, to exhibit information to a user. Since the displaying of information on the TFT-LCD is presented in a full screen ON/OFF fashion, in case that only a local area of the full screen is needed in carrying out the operation of information displaying, the remaining portions of the screen must be simultaneously put into operation, leading to undesired consumption of power. 
     According to practical experiences of use, when an idle area of a screen is larger than an in-operation area, the power consumption caused by the idle area of the screen will substantially reduce the in-service time period of a battery pack, especially for a system device that is long term carried, eventually affecting convenience and portability thereof. (For example, for a regular mobile phone, in order to acquire time data, a display of the mobile phone has to turn the full screen on, but an image displayed area for showing the time data may only take only a minor fraction of the full screen.) 
     SUMMARY OF THE INVENTION 
     In view of the above discussed problems of the known techniques, the present invention aims to provide a local area image displaying system for a screen of a display device, which allows a target image to be displayed in a selected local image displaying area of the screen of the display device. Since the display device only consumes power for the selected local image displaying area of the screen, unnecessary power consumption can be reduced. 
     In an embodiment of the present invention, screen signals supplied to an LCD screen are determined by controlling matrix-arranged switches for displaying operation of the LCD screen. A gate driving circuit for horizontal rows of the matrix-arranged switches supplies gate voltages to control switching-on/off of each pixel unit; and a data driving circuit for vertical columns of the matrix-arranged switches supplies data voltages to provide a suitable voltage signal to each pixel unit. 
     A timing controller and a microprocessor unit connected to the timing controller together control the displaying operation of the LCD screen. The timing controller generates a data driving circuit control signal and a gate control signal. The data driving circuit control signal controls the operation timing of the data driving circuit. The gate control signal controls the operation timing of the gate driving circuit. 
     The data driving circuit supplies the data voltages through data lines to selected ones of the pixel units. The gate driving circuit supplies gate voltages through gate lines to the selected ones of the pixel unit. The pixel units are arranged in a pixel matrix and the pixel units that are arranged in a pixel matrix define a global displaying area. 
     Based on the local displaying area in which a target image is to be displayed on the global displaying area, the timing controller sends the control signals to the data lines of the data driving circuit and the gate lines of the gate driving circuit that are covered by the local displaying area in order to enable the pixel units covered by the local displaying area, whereby the target image is displayed on the selected local displaying area. 
     With the technical solution provided by the present invention, the timing controller may function to supply desired control signals to the data driving circuit and the gate driving circuit according to the desired local displaying area so that data voltages and gate voltages are only supplied to the data lines and gate lines covered by the local displaying area. Thus, the present invention provides a displaying method that exhibits only an in-operation area and turns off signals associated with non-operated displaying areas of the LCD screen. In this way, power utilization efficiency can be enhanced and in-service time period of a battery pack is extended. 
     These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. It is to be understood that both the foregoing general description and the following detailed description are examples, and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given herein below for illustration only, and thus is not limitative of the present invention, and wherein: 
         FIG. 1  shows a system block diagram of a local area image displaying system constructed in accordance with the present invention for a screen of display device; 
         FIG. 2  shows a schematic view of a driving system of the display device illustrated in the embodiment of  FIG. 1 ; 
         FIG. 3  shows a schematic view of a pixel unit of the embodiment illustrated in  FIG. 2 ; 
         FIG. 4  shows a schematic view illustrating a global displaying area of the display device; 
         FIG. 5  shows a schematic view illustrating a local displaying area of the display device; and 
         FIG. 6  shows a schematic view illustrating another local displaying area of the display device. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description refers to the same or the like parts. 
     With reference to  FIG. 1 , which shows a system block diagram of a local area image displaying system constructed in accordance with the present invention for a screen of a display device, an image data source  10  provides a RGB analog signal that is comprised of red, green, and blue component to an analog to digital converter (ADC)  11  for conversion of the analog signal into a digital signal, which is then applied to a scaler  12 . The scaler  12  functions to perform adjustment in accordance with image-related parameters regarding to image resolution or shape and size contained in the digital signal provided by the analog to digital converter  11 . 
     The scaler  12  is connected to a microprocessor unit  13  and an on-screen display (OSD) adjuster  14 . The OSD adjuster  14  allows for fine adjustment of displaying-related parameters, such as brightness and contrast of screen displaying and horizontal and vertical positioning, of the image data that have been subjected to adjustment realized through the scaler  12 . Further, the OSD adjuster  14  can be embedded or optional according to the numbers of language and font that the system can support. 
     During the processing of image data, the microprocessor unit  13  carries out reception and conversion of the image signal and interlaced scanning. In addition, it also helps the OSD adjuster  14  in appearance adjustment and font conversion. The scaler  12  transmits the adjusted and integrated image data as an image data signal s 1  to a timing controller  2 . 
     The timing controller  2  comprises an image signal source connection portion  21 , a data driving circuit connection port  22 , and a gate driving circuit connection port  23 . The image data signal s 1  provided by the scaler  12  is fed to the timing controller  2  through the image signal source connection port  21 . 
     The timing controller  2  uses the data driving circuit connection port  22  and the gate driving circuit connection port  23  to respectively connect with the data driving circuit  31  and the gate driving circuit  32 . The timing controller  2  generates a data driving circuit control signal s 2  and a gate control signal s 3  that respectively control the operation timings of the data driving circuit  31  and the gate driving circuit  32 . 
     A display device  4  is connected to the data driving circuit  31  and the gate driving circuit  32 , whereby the data driving circuit  31  and the gate driving circuit  32  supply data voltages and gate voltages to the display device  4  for displaying an image thereon. 
     As shown in  FIG. 2 , which is a schematic view of a driving system of the display device illustrated in the embodiment of  FIG. 1 , the display device  4  comprises a pixel matrix  5 , which is formed by arranged a plurality of pixel units  51  in a matrix. The pixel matrix  5  defines a global displaying area W on the display device  4 . Each pixel unit  51  has a data terminal  511 , a gate terminal  512 , a switch unit  513 , and a capacitor  514  (see  FIG. 3 ). 
     The data driving circuit  31  comprises a plurality of data lines S 1 -S 6 . These data lines S 1 -S 6  are respectively connected to the data terminals  511  of the pixel units  51 . The data driving circuit  31  selectively supplies a data voltage to the data line S 1 -S 6  of at least one selected pixel unit. And also, the image data signal s 1  and the data driving circuit control signal s 2  generated by the timing controller  2  are transmitted with the data voltages generated by the data driving circuit  31  to the data lines S 1 -S 6  of the selected pixel units  51  of the pixel matrix  5 . 
     The gate driving circuit  32  comprises a plurality of gate lines G 1 -G 6 . These gate lines G 1 -G 6  are respectively connected to the gate terminals  512  of the pixel units  51 . The gate driving circuit  32  selectively supplies a gate voltage to the gate lines G 1 -G 6  of at least one selected pixel unit. And also, the gate control signal s 3  generated by the timing controller  2  is transmitted with the gate voltages generated by the gate driving circuit  32  to the gate lines G 1 -G 6  of the selected pixel units  51  of the pixel matrix  5 . 
     In  FIG. 3 , the pixel unit  51  uses the data terminal  511  and the gate terminal  512  to respectively receive the data voltage supplied by the data driving circuit  31  through the data line S 1 -S 6  and the gate voltage supplied by the gate driving circuit  32  through the gate lines G 1 -G 6 . The switch unit  513  is a switching circuit that is comprised of for example a transistor based switching unit, such as a metal-oxide-semiconductor field effect transistor (MOS-FET) or other power transistor. 
     To display the image of the image data signal s 1  with the pixel units  51 , the gate voltage supplied by the gate driving circuit  32  controls the switch units  513  of the pixel units  51  and the data voltage supplied by the data driving circuit  31  conveys primary color signals of red, blue, and green fed from the image data source  10 . 
     The gate driving circuit  32  operates to control the supply of a gate voltage to each gate line G 1 -G 6  of the pixel matrix  5 . When an image is subjected to a one-time row-by-row scanning operation, the gate driving circuit  32  supplies the gate voltage to the gate terminals  512  of the pixel units  51  to close all the switch units  513  comprised in a row to allow the data driving circuit  31  to supply the data voltages that contain image signals to the data terminals  511  of the pixel units  51 . 
     The data driving circuit  31  operates to control the supply of a data voltage through each individual data line S 1 -S 6  to the data terminals  511  of the pixel units  51  of the pixel matrix  5 . When the gate driving circuit  32  close or open all the switch units  513  comprised in a row, the data driving circuit  31  supplies the data voltages to a whole row of the pixel matrix  5  in accordance with the image data signal s 1  and the data driving circuit control signal s 2  generated by the timing controller  2  to exhibit the pixels that form a combined and complete image. 
     Further, to display various colors for a complete image in the display device  4 , it is obtained through the color levels of the sub-pixel of the primary color signals of red, blue, and green from the image data source  10 . Color level control is performed in accordance with the level of gate voltage supplied from the gate driving circuit  32 . 
     For the present invention that realizes displaying image in a local portion of a screen, the timing controller  2  generates, in response to a local displaying area W 1  (see  FIG. 5 ), which comprises a fraction of the global displaying area W (see FIG.  4 ), for displaying a target image therein, a data driving circuit control signal s 2  and a gate control signal s 3  associated with the said local displaying area W 1 . The data driving circuit  31  bases on the data driving circuit control signal s 2  associated with the local displaying area W 1  to supply data voltages to the data lines S 3 , S 4  of the pixel units  51  that are covered by the local displaying area W 1  and also, the gate driving circuit  32  bases on the gate control signal s 3  associated with the local displaying area W 1  to supply gate voltages to the gate lines G 3 , G 4  of the pixel units  51  covered by the local displaying area W 1 , whereby the pixel units  51  contained in the local displaying area W 1  can be enabled to display the target image in the selected local displaying area W 1 . 
     For displaying the target image in the local displaying area W 1 , the embodiment discussed above employs selective driving of the data lines S 3 , S 4  and gate lines G 3 , G 4  associated with the local displaying area W 1 . Alternatively, it is also feasible to simultaneously drive all the data lines S 1 -S 6 , but only drive the gates lines G 3 , G 4  associated with the local displaying area W 1 . This also allows the pixel units  51  contained in the local displaying area W 1  to be enabled for displaying the target image in the selected local displaying area W 1 . It is apparent that, alternatively, only the data lines S 3 , S 4  associated with the local displaying area W 1  are driven, but all the gate lines G 1 -G 6  are simultaneously driven for enabling only the pixel units  51  contained in the local displaying area W 1  to display the target image in the selected local displaying area W 1 . 
     Similarly, when an attempt is made to display a target image in a different local displaying area W 2  (see  FIG. 6 ) that comprises a fraction of the global displaying area W, the data driving circuit  31  drives the data lines S 5 , S 6  associated with the pixel units  51  covered by the local displaying area W 2  and the gate driving circuit  32  drives the gate lines G 1 , G 2  associated with the pixel units  51  covered by the local displaying area W 2 , whereby the pixel units  51  contained in the local displaying area W 2  can be properly enabled to display the target image in the selected local displaying area W 2 . 
     Additional advantages and modifications will readily occur to those proficient in the relevant fields. The invention in its broader aspects is therefore not limited to the specific details and representative embodiments 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.