Patent Publication Number: US-7719514-B2

Title: Apparatus and method for converting a digital video signal to conform with a display panel format

Description:
TECHNICAL FIELD 
   The present invention relates to a display panel of the active matrix type, and more particularly to a drive apparatus, a drive method and a display panel drive system which can commonly comply with display panels of various display formats. 
   This Application claims priority of Japanese Patent Application No. 2003-307921, filed on Aug. 29, 2003, the entirety of which is incorporated by reference herein. 
   BACKGROUND ART 
   In display panels of the active matrix type, e.g., liquid crystal panels, etc., there is the trend where the number of pixels is increased with realization of high definition devices (display panels). In the case where the number of pixels is increased in such a way, since write time becomes short in dot sequential drive system where video signals are written by one pixel, there is employed a plural pixel simultaneous sampling system in which plural video signal input lines for delivering video signals from the external to the liquid crystal are provided to simultaneously perform sampling of video signals delivered from the plural video signal input lines to deliver the video signals thus sampled to plural pixels. 
   When the liquid crystal panel is caused to be driven by the plural pixel simultaneous sampling system, it is possible to obtain sufficient write time of video signal. Accordingly, in display panels of increased pixel number, i.e., relatively high definition active matrix type such as XGA (eXtended Graphic Array: 1024×768), WXGA (Wide eXtended Graphic Array: 1386×768), or SXGA (Super eXtended Graphic Array: 1400×1500), and display panels of increased pixel number, i.e., high definition active matrix type such as SXGA+(Super eXtended Graphic Array PLUS : 1400×1050), UXGA (Ultra eXtended Graphic Array: 1600×1200), Full HD (Full High Definition: 1920×1080), the plural pixel simultaneous sampling system is employed so that write operation of video signals can be satisfactorily executed. 
   The plural pixel simultaneous sampling system for driving the liquid crystal panel will be explained by using  FIGS. 1 and 2 . 
     FIG. 1  is a liquid crystal drive system  50  mounted in a liquid crystal projector, which comprises liquid crystal panels  60 R,  60 B,  60 G which are respectively liquid crystal panel for red, liquid crystal panel for green and liquid crystal panel for blue driven by the plural pixel simultaneous sampling system. 
   The respective liquid crystal panels  60 R,  60 C,  60 B that the liquid crystal panel drive system  50  has are a liquid crystal panel complying with the XGA format, wherein video signals are simultaneously written by 6 (six) pixels with respect to pixels in a horizontal direction by the plural pixel simultaneous sampling system. 
   The liquid crystal panel drive system  50  comprises a DSD (Digital Signal Driver)  51  including a DSD core  51   a  for implementing gamma correction and/or color unevenness correction, etc. to digital video signals for red (R), digital video signals for green (G) and digital video signal for blue (B) which are delivered from the external, and LCD drivers  52 ,  53 ,  54  for converging digital video signals which have been caused to undergo correction processing by the DSD  51  into analog video signals to deliver the analog video signals thus obtained to the respective liquid crystal panels  60 R,  60 B,  60 G. The respective liquid crystal panels  60 R,  60 B,  60 G are respectively mounted at liquid crystal panel modules  61 R,  61 G,  61 B along with horizontal drive circuit and vertical drive circuits which are not shown. 
   The LCD drivers  51 ,  52 ,  53  serve to convert digital video signals delivered from the DSD  51  into analog video signals of which number corresponds to the number of sampling for performing simultaneous sampling of digital video signals delivered from the DSD  51 . At the liquid crystal panels  60 R,  60 G,  60 B which comply with the XGA format, since the number of simultaneous sampling operations is set to six (pixels), the LCD drivers  52 ,  53 ,  54  serve to convert digital video signals delivered into six parallel analog video signals. 
   It is to be noted that timing pulses for driving the respective liquid panels  60 R,  60 G,  60 B are generated by a TG (Timing Generator)  51   b  of the DSD  51 . 
   Subsequently, the plural pixel simultaneous sampling system will be explained in detail by using the liquid crystal panel module  61 R shown in  FIG. 2 . It is to be noted that since plural pixel simultaneous sampling systems at liquid crystal panels  60 R,  60 G,  60 B are entirely the same, explanation will be given by using, as representative, the liquid crystal panel module  61 R on which liquid crystal panel  60 R is mounted. 
   As shown in  FIG. 2 , the liquid crystal panel module  61 R is supplied, through video signal supply lines VSIGI to VSIG 6 , six parallel analog signals which have been converted at the LCD driver  52 . 
   The liquid crystal panel module  61 R comprises groups of sampling switches SW N  each comprised of six sampling switches for simultaneously performing sampling of six signal lines  63  among signal lines  63  that the liquid crystal panel  60 R has. 
   The groups of sampling switches are driven in order of groups of sampling switches SW 1 , SW 2 , . . . , SW N-1 , and SW N  in accordance with switch pulses delivered from a horizontal drive circuit  62 . Thus, at the signal lines  63 , video signals are simultaneously sampled in units of six video signals. As a result, video signals are written into pixels  64  in the row direction selected by vertical drive circuits (not shown). 
   Since it is necessary to sufficiently ensure write time of video signal in general, it is necessary that according as resolution of the liquid crystal panel becomes higher, it is required to increase the number of pixels to be simultaneously sampled by taking the transistor characteristic and/or the switch characteristic of the liquid crystal panel, etc. into consideration. For example, in the SXGA, it is necessary that the number of pixels subject to simultaneous sampling is set to 12 (pixels). In the UXGA, it is necessary that the number of pixels subject to simultaneous sampling is set to 24 (pixels). 
   As stated above, in the conventional plural pixel simultaneous sampling system, since it is necessary to change the number of pixels subject to simultaneous sampling in accordance with difference of the display format of the liquid crystal panel, it is required to also change the number of video signals delivered to the liquid crystal panel, i.e., the number of parallel analog video signals converted at the LCD drivers  52 ,  53 ,  54  in  FIGS. 1 and 2  in accordance with the display format. 
   Accordingly, in order that the liquid crystal panel drive system  50  is caused to comply with liquid crystal panels of various display formats, LCD drivers  52 ,  53 ,  54  are required by the number of display formats. As a result, there would take place the problem that the cost is increased, and/or the apparatus becomes large-sized. 
   In addition, in the plural pixel simultaneous sampling system, there is the problem that there would take place ghost which is the phenomenon that the same image is displayed in the state shifted in a manner to overlap from image primarily displayed by the phase relationship between video signal and timing pulse. 
   DISCLOSURE OF THE INVENTION 
   Problems to be Solved by the Invention 
   An object of the present invention is to apply (provide) a novel drive apparatus and a novel drive method for display panel, and a novel display panel drive system which can eliminate or solve the problems that prior arts as described above have. 
   Another object of the present invention is to provide a drive apparatus, a drive method and a display drive panel system which are adapted for avoiding occurrence of ghost and for driving display panels of various display formats. 
   The drive apparatus according to the present invention is directed to a drive apparatus adapted for driving a display panel having x×y number of pixels arranged in a matrix form at intersecting portions of x number of signal lines disposed in a column direction and y number of gate lines disposed in a row direction, which comprises: data arrangement converting means for converting a digital video signal of m bits into data arrangement in conformity with display format of the display panel; first signal processing means for converting the digital video signal of the m bits which has been converted into the data arrangement in conformity with the display format by the data arrangement converting means into parallel analog video signals of p-phase; second signal processing means for developing the analog video signals of the p-phase which have been converted by the first signal processing means into analog video signals of x/k-phase to deliver the analog video signals thus developed to the x/k number of video signal supply lines which have been selected from N number of video signal supply lines; and signal line selecting means for sequentially selecting, one by one, at the same timing, desired signal lines from respective groups of the x/k number of signal lines obtained by dividing the x number of signal lines into the k number of signal lines adjacent in the state where they do not overlap with each other to perform sampling of the analog video signals delivered via the x/k number of video signal supply lines with respect to the selected signal lines. 
   Here, x, y, p, m, k are natural numbers, and N is natural number which satisfies N≧(x/k). 
   The drive method according to the present invention is directed to a drive method of driving a display panel having x×y number of pixels arranged in a matrix form at intersecting portions of x number of signal lines disposed in a column direction and y number of gate lines disposed in a row direction, which comprises: converting a digital video signal of m bits into data arrangement in conformity with display format of the display panel; converting the digital video signal of the m bits which has been converted into the data arrangement in conformity with the display format into parallel analog video signals of p-phase; developing the analog video signals of the p-phase into analog video signals of x/k-phase to deliver the analog video signals thus developed to the x/k number of video signal supply lines which have been selected from N number of video signal supply lines; sequentially selecting, one by one, at the same timing, desired signal lines from respective groups of the x/k number of signal lines obtained by dividing the x number of signal lines into the k number of signal lines adjacent in the state where they do not overlap with each other; and performing sampling of the analog video signals delivered via the x/k number of video signal supply lines with respect to the selected signal lines. 
   Here, x, y, p, m, k are natural numbers, and N is natural number which satisfies N≧(x/k). 
   The display panel drive system according to the present invention is directed to a display panel drive system of driving a display panel having x×y number of pixels arranged in a matrix form at intersecting portions of x number of signal lines disposed in a column direction and y number of gate lines disposed in a row direction, which comprises: a data arrangement converting unit for converting a digital video signal of m bits into data arrangement in conformity with display format of the display panel; a signal processing unit for converting the digital video signal of the m bits which has been converted into the data arrangement in conformity with the display format by the data arrangement converting unit into parallel analog video signals of p-phase; and a display panel module including the display panel having an arbitrary display format, signal processing means for developing the analog video signals of the p-phase which have been converted by the signal processing unit into analog video signals of x/k-phase to deliver the analog video signals thus developed to N number of video signal supply lines, a vertical drive circuit connected to the gate lines and serving to linearly sequentially drive the gate lines to select the x number of pixels in the row direction, signal line selecting means for sequentially selecting, one by one, at the same timing, desired signal lines from respective groups of the x/k number of signal lines obtained by dividing the x number of signal lines into the k number of signal lines adjacent in the state where they do not overlap with each other to perform sampling of the analog video signals delivered via the x/k number of video signal supply lines with respect to the selected signal lines, and video signal writing means for writing the analog video signals which have been caused to undergo sampling at the signal lines by the signal line selecting means into the pixels in the row direction which have been selected by the vertical drive circuit. 
   Here, x, y, p, m, k are natural numbers, and N is natural number which satisfies N≧(x/k). 
   In the present invention, the number of pixels which can be written at a time is greatly increased to a degree of, e.g., 100 pixels or more, as compared to the plural pixel simultaneous sampling system of the conventional system. Accordingly, since sufficient write time can be ensured, it becomes possible to realize stable write operation. 
   Further, in the present invention, the display panel module is designed so as to comply with the highest definition display format, e.g., Full HD, thereby making it possible to flexibly cope with display panels of any display format only by adjustment of the number of developments of analog video signals, and/or simple adjustment to suitably change timing, etc. of sampling, etc. Particularly, in display formats SXGA+, UXGA, Full HD of high resolution, the system configuration can be greatly simplified. 
   Furthermore, in the present invention, desired signal lines are sequentially selected, one by one, at the same timing, from the respective groups of signal lines obtained by dividing signal lines of the display panel, thereby making it possible to completely remove occurrence cause of ghost taking place resulting from the fact that video signal is inserted (written) by deviation of phase relationship between video signal and timing pulse also except for video signals which are to be primarily written. 
   Still further objects of the present invention and practical merits obtained by the present invention will become more apparent from the description of the embodiments which will be given below with reference to the attached drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram of a conventional liquid crystal panel drive system to which plural pixel simultaneous sampling system is applied. 
       FIG. 2  is a circuit diagram showing a liquid crystal panel module used for explaining, in detail, plural pixel simultaneous sampling system. 
       FIG. 3  is a block circuit diagram showing display panel drive system according to the present invention. 
       FIG. 4  is a block circuit diagram showing display panel module that the display panel drive system has. 
       FIG. 5  is a block circuit diagram showing display panel module that the display panel drive system has. 
       FIG. 6  is a view showing ratio between write time of video signal by the conventional system and write time which can be ensured in the above-mentioned display panel drive system. 
       FIG. 7  is a view showing the number of switches SW N  necessary for respective display formats. 
       FIG. 8  is a view for explaining the number of developments of video signals by post-drive. 
       FIGS. 9A to 9G  are views showing, every display format, the state where video signals are developed by the post-drive. 
       FIGS. 10A to 10F  are views showing the state where video signals have been written into pixels by the signal line select sampling system. 
   

   BEST MODE FOR CARRYING OUT THE INVENTION 
   The embodiments of a drive apparatus, a drive method and a display panel drive system according to the present invention will now be explained in detail with reference to the attached drawings. 
   The liquid crystal panel drive system  1  according to the present invention will be explained by using  FIG. 3 . 
   The liquid crystal panel drive system  1  is provided at, e.g., liquid crystal projector of three plate (panel) type, etc., and comprises, as liquid crystal panel, a liquid crystal panel  9 R for red, a liquid crystal panel  9 G for green and a liquid crystal panel  9 G for blue. 
   Moreover, the liquid crystal panel drive system  1  comprises a DSD (Digital Signal Driver)  2  for implementing a predetermined signal processing to a digital video signal delivered from the external, a Pre Driver  3  for driving the liquid crystal panel  9 R, a Post Driver  4 , a Pre Driver  5  for driving the liquid crystal panel  9 G, a Post Driver  6 , a Pre Driver  7  for driving the liquid crystal panel  9 B, and a Post Driver  8 . 
   The liquid crystal panel  9 R and the Post Driver  4  are caused to be of the module configuration as a liquid crystal panel module  10 R along with vertical drive circuit (not shown). Similarly, the liquid crystal panel  9 G and the Post-Driver  6  are caused to be of module configuration as a liquid crystal panel module  10 G along with vertical drive circuit (not shown). The liquid crystal panel  9 B and the Post Driver  8  are caused to be of the module configuration as a liquid crystal panel module  10 B along with vertical drive circuits (not shown). 
   The DSD  2  comprises a DSD core  2   a , a memory  2   b , and a TG (Timing Generator)  2   c.    
   The DSD core  2 a serves to implement digital signal processing such as gamma correction and/or color unevenness correction, etc. to respective digital video signals of RGB delivered from the external. Respective digital video signals of RGB are delivered from the external as parallel data of 12 bits. The numeric value of the 12 bits is based on the fact that video signal is handled by 12 bits in the liquid crystal panel drive system  50  shown as the prior art, and is a value only diverted (used) from a viewpoint of design. Accordingly, it is not necessarily required that this value is 12 bits, and takes m (m is natural number) bits. 
   In the memory  2   b , there are stored respective digital video signals of RGB which have been caused to undergo digital signal processing at the DSD core  2   a . The respective digital video signals of RGB stored in the memory  2   b  are converted into data arrangement corresponding to display format such as SVGA, XGA, WXGA, SXGA, SXGA+, UXGA, or Full HD, and are respectively delivered to Pre Drivers  3 ,  5 ,  7  in parallel as digital data of 12 bits. The Pre Driver  3  is supplied, in parallel, with digital video signals R 1 , R 2  of 12 bits. The Pre Driver  5  is supplied, in parallel, with digital video signal of  12  bits as digital video signals G 1 , G 2 . The Pre Driver  7  is supplied, in parallel, with digital video signal of 12 bits as digital video signals B 1 , B 2 . 
   The timing generator  2   c  that the DSD  2  has generates timing pulse S 2  delivered to the Pre Drivers  3 ,  5 ,  7 , and timing pulse S 1  delivered to the liquid crystal panel modules  10 R,  10 G,  10 B. The Pre Drivers  3 ,  5 ,  7  and the liquid crystal panel modules  10 R,  10 G,  10 B are controlled in synchronism with the timing pulse S 1  or S 2 . 
   The Pre Drivers  3 ,  5 ,  7  respectively convert digital video signals inputted in parallel from the DSD  2  into analog video signal of p (p is natural number)-phase on the basis of the timing pulse S 2  synchronous with video signal to respectively deliver those video signals to the Post Drivers  4 ,  6 ,  8 . For example, the Pre Drivers  3 ,  5 ,  7  perform conversion into analog video signal of 12 phase on the premise that p is set to 12. It is to be noted that explanation will be given in the following description on the assumption that the Pre Drivers  3 ,  5 ,  7  convert digital video signal inputted from the DSD  2  into analog video signal of p=12 phase. 
   Moreover, the Pre Drivers  3 ,  5   7  also respectively generate pre-charge signal (PSIG) delivered to the liquid crystal panels  9 R,  9 G,  9 B, and panel common DC voltage (VCOM). 
   Then, the liquid crystal panel modules  10 R,  10 G,  10 B will be explained. Since the respective liquid crystal panel modules  10 R,  10 Q,  10 B are all caused to be of the same configuration except for output wavelength regions of liquid crystal panels  9 R,  9 G, 9 B that the respective liquid crystal panel modules  10 R,  10 G,  10 B have, the liquid crystal panel  10 R will be explained as representative. 
   As shown in  FIG. 4 , the liquid crystal panel module  10 R comprises Post Driver  4 , liquid crystal panel  9 R, a vertical drive circuit  12 , a pre-charge drive circuit, and a group of signal line select switches  14 . 
   The Post Driver  4  respectively develops analog video signals of 12 phase delivered from the Pre Driver  3  into video signals corresponding to the number of outputs which comply with display formats such as SVGA, XGA, WXGA, SXGA, SXGA+, UXGA, and/or Full HD on the basis of timing pulse SI synchronous with video signal to deliver the video signals thus developed to the liquid crystal panel  9 R through video signal supply line VSIG N  (N is natural number) and the group of signal line select switches  14 . 
   The development processing from the analog signals of 12 phase at the Post Driver  4  into video signals corresponding to the number of outputs which comply with the above-described display format is processing based on the sampling system executed in the liquid crystal panel drive system  1 . 
   The sampling system of the liquid crystal panel drive system  1  is a system of first selecting signal line which will be described later that the liquid crystal panel  9 R has by the number of outputs of video signals which have been developed at the Post Driver  4  to subsequently perform, plural times, an operation to write, at a time, at the same timing, video signals developed with respect to selected signal lines to perform sampling with respect to all signal lines. This sampling system is called signal line select sampling system. 
   The number of video signals developed by the Post Driver  4  on the basis of the signal line select sampling system is relatively determined by the display format of the liquid crystal panel  9 R and the number of write operations for writing video signals onto all signal lines of the liquid crystal panel  9 R. 
   For example, when the display format of the liquid crystal panel  9 R is high definition display format having large number of pixels, it is necessary to increase the number of developments of video signals. Moreover, when the number of times required for writing video signals onto all signal lines of the liquid crystal panel  9 R is decreased, it is required to increase signal lines onto which video signals are to be written at a time. Accordingly, it is necessary to also increase the number of developments of video signals. The signal line select sampling system will be explained in detail later. 
   The liquid crystal panel  9 R comprises plural gate lines  21  wired in a row form, plural signal lines  22  wired in a column form, and pixels  23  disposed at portions where both lines intersect with each other. 
   The pixel  23  is composed of Thin Film Transistor (TFT) which is not shown, and liquid crystal cell which is not similarly shown. The gate electrode of the TFT is connected to corresponding gate line  21 , the source electrode thereof is connected to corresponding signal line  22 , and the drain electrode thereof is connected to one electrode (pixel electrode) of corresponding liquid crystal cell. The other electrode (opposite electrode) of the liquid crystal cell is supplied with panel common DC voltage (VCOM) generated at the Pre Driver  3  as a predetermined opposite potential. 
   The vertical drive circuit  12  is divided into left and right portions, which are connected to the gate lines  21 , and serves to linearly sequentially drive the connected respective gate lines  21  from the both sides thus to select pixels  23  in a row direction. 
   The pre-charge drive circuit  13  applies, in advance, prior to write operation of video signal, pre-charge signal (PSIG) delivered from the Pre Driver  3  through pre-charge line (not shown) to respective signal lines  22  to perform pre-charge operation. This pre-charge operation is performed prior to write operation of video signals with respect to respective pixels  23 . 
   A group of signal line select switches  14  is each comprised of plural switches for performing sampling of video signals delivered from the Post Driver  4  through video signal supply line VSIG N  with respect to the signal line  22 . The plural switches that the group of signal line select switches  14  are switched at the same timing on the basis of timing pulse S 1  delivered from TG2c of the DSD2 to repeat such switching operations plural times to thereby perform sampling of video signals with respect to all signal lines  22  that the liquid crystal panel  9 R has. The video signals which have been caused to undergo sampling with respect to the signal line  22  are written into pixels  23  in the row direction selected by the vertical drive circuit  12 . 
   Subsequently, the configuration of the liquid crystal panel module required in carrying out the signal line select sampling system will be described in detail by using the liquid crystal panel module  10 R with reference to  FIG. 5 . 
   As shown in  FIG. 5 , N (N is natural number) number of video signal supply lines VSIG 1  to VSIG N  connected to the Post Driver  4  are respectively connected to the signal lines  22  through switches SW N  that the group of signal line select switches  14  have. The switches SW N  are provided, one by one, at six signal lines  22  adjacent in the state where they do not overlap with each other among the signal lines  22 , and serve to select single signal line  22  every time timing pulse S 1  is delivered from the group of signal lines with the six signal lines  22  being as unit. 
   For example, at the switch SW 1 , signal line  22  located at the left end of the group of signal lines is selected at timing by the first timing pulse S 1  and signal line adjacent at the right side is selected at the subsequent timing Thus, the remaining four signal lines  22  are selected in sequence. Similarly, at the switch SW N  except for the switch SW , signal lines  22  are selected at the same timing as that of the switch SW 1 , in order from the left end of the group of six signal lines. 
   As described above, respective switches SW N  are simultaneously operated by timing pulse S 1  to select respective one signal lines  22 . Accordingly, the number of write operations with respect to all signal lines  22  that the liquid crystal panel  9 R has becomes equal to the number of selections of the signal lines  22  by the switch SW N , i.e., six times here. 
   The switches SW N  may be provided in units of six signal lines as described above with respect to the signal lines  22  that the liquid crystal panel  9 R has, and may be provided in units of arbitrary number of signal lines, e.g., in units of four signal lines or in units of eight signal lines. According as the number of signal lines  22  to be selected by the switch SW N  is reduced and the number of switches SW N  installed or provided is increased, the number of signal lines  22  which can be subject to sampling at a time becomes large. For this reason, it becomes possible to sufficiently ensure write time with respect to the signal line  22 . 
   Ratios of write time A which can be ensured in the signal line select sampling system of the conventional system with respect to write time B by the plural pixel simultaneous sampling system (write time required in the case where six pixels are caused to undergo simultaneous sampling) are respectively shown in the case where the number of signal lines  22  to be selected is set to 1, 2, 4, 6, 8 are shown in  FIG. 6 . 
   As shown in  FIG. 6 , it can be understood that, in the signal line select sampling system, according as the number of signal lines to be selected by the switch SW N  becomes smaller, longer write time can be ensured as compared to the conventional system. 
   If the liquid crystal panel  9 R has the same display format, the number N of switches SW N  constituting the group of signal line select switches  14  is determined by the number of signal lines  22  to be selected. For example, if the number of signal lines  22  to be selected becomes small, required number of switches SW N  is increased. If the number of signal lines  22  to be selected becomes large, required number of switches SW N  is decreased. 
   Moreover, if the number of signal lines  22  to be selected is the same, the number of switches SW N  is determined by the display format of the liquid crystal panel  9 R. For example, when the number of selected signal lines  22  is set to six, the number of pixels in the row direction becomes equal to 1386 at the liquid crystal panel  9 R in which the display format is WXGA. From this fact, the number of signal lines  22  also becomes equal to 1386. Thus, from the relationship expressed as 1386/6=231, 231 switches SW N  are required. Similarly, in the case where the number of signal lines  22  to be selected is set to six and the display format is caused to be Full HD, there results 1920/6=320. Thus, 320 switches SW N  are required. The number of switches SW N  necessary every display format in the case where the number of signal lines  22  to be selected is fixed to six is shown in  FIG. 7 . In  FIG. 6 , “A” indicates write time by the conventional system, and “B” indicates write time by the signal line selection system. 
   Meanwhile, as shown in  FIG. 7 , in the case where the display formats of the liquid crystal panel  9 R are SVGA, XGA, SXGA, SXGA+, and UXGA, the respective numbers of signal lines  22  cannot be divided in the case where the number of signal lines  22  to be selected by the switch SW N  is set to six. 
   Accordingly, when the number of signal lines is less than six, signal line  22  in which the number of switches SW N  to be selected is less than six would take place. However, one switch SW N  is assigned also with respect to the signal line  22 . For example, since there results 800/6=133.33 . . . in the SVGA, the number of required switches SW N  is set to 134 to cope with such situation. 
   At this time, dummy signal line and dummy pixel are added to the liquid crystal panel  9 R in order to comply with one switch SW 134  which has been increased. In the SVGA, 133 ×6=798 signal lines  22  are caused to comply therewith up to the switches SW 1  to SW 133  Since six signal lines are supplemented by the switch SW 134 ,  804  signal lines  22  are necessary. In the display format of SVGA, since  800  signal lines  22  exist, four dummy signal lines are newly required. In view of the above, only four dummy pixel number (D) is also added by four in the row direction in correspondence with four dummy signal lines to be newly supplemented. The number of horizontal pixels shown in  FIG. 7  is the number of horizontal pixels (Ha) in which dummy pixel number (D) is taken into consideration. In  FIG. 7 , “*” indicates that no dummy pixel is required. 
   Also in regard to other display formats XGA, SXGA, SXGA+and UXGA, dummy signal lines and dummy pixels are supplemented to the liquid crystal panel  9 R in entirely the same manner to allow the number of horizontal pixels to be the number of horizontal pixels (Ha) as shown in  FIG. 7 , thereby making it possibly to take matching with the number of switches SW N . 
   Subsequently, video signal delivered from the Post Driver  4  to the switch SW N  through video signal supply lines VSIG 1  to VSIG N  will be explained. The video signal delivered from the Post Driver  4  to the switch SW N  through video signal supply lines VSIG 1  to VSIG N  is a video signal developed from analog video signals of 12-phase at the Post Driver  4 . 
   As described above, in the signal line select sampling system carried out in the liquid crystal panel drive system  1  according to the present invention, sampling of video signal is performed by switching operation by the switch SW N  with respect to the signal line  22  of the liquid crystal panel  9 R. 
   Accordingly, video signals delivered from the Post Driver  4  through video signal supply lines VSIG 1  to VSIG N  are also required by the number of switches SW N . 
   In view of the above, the Post Driver  4  develops video signals of 12-phase delivered from the Pre Driver  3  by the number of switches SW N  determined by the display format of the liquid crystal panel  9 R and the number of write operations with respect to the signal line  22  that the liquid crystal panel  9 R has to output the video signals thus developed. 
   The number of outputs, i.e., the number of developments of video signals from the Post Driver  4  every display formats such as SVGA, XGA, WXGA, SXGA, SXGA+, UXGA, Full HD in the case where the number of signal lines  22  to be selected by the switch SW N  is set to six is shown in  FIG. 8 . As stated above, the number of developments of video signals from the Post Driver  4  is determined by the display format of the liquid crystal panel  9 R and the number of signal lines  22  to be selected by the switch SW N . 
   From this fact, when the number of signal lines  22  of the liquid crystal panel  9 R is set to x and the number of selected signal lines  22  per one switch SW N  is set to k, switches SW N  are required with respect to respective groups of x/k number of signal lines consisting of k number of signal lines adjacent in the state where they do not overlap with each other. For this reason, the number of developments by the Post Driver  4  also results in x/k phase. 
   Moreover, the total number of developments shown in  FIG. 8  indicates the number of developments per one phase of analog video signals of p-phase delivered from the Pre Driver  3  to the Post Driver  4 . For example, when p is set to 12, the Post Driver  4  respectively develops analog video signals of 12-phase into analog video signals of 27-phase as shown in  FIG. 9A  in the Full HD. 
   At this time, the number of video signals developed into video signals of 27-phase becomes equal to 12×27=324 in total. Since the number of outputs by the Post Driver  4  becomes equal to 320 from the number of switches SW N  necessary in the case where the display format is Full HD and the number of selected signal line  22  is six, four video signals are delivered to the dummy terminal, etc. so that they are not outputted. 320 video signals except for the above are delivered to 320 video signal supply lines VSIG 1 , to VSIG 320  connected to the Post Driver  4 . 
   Similarly, in the case where the display format of the liquid crystal panel  9 R is UXGA, SXGA+, SXGA, WXGA, XGA, SVGA, the Post Driver  4  develops the video signals of 12-phase by the total number of developments shown in  FIG. 8  to output the video signals thus developed to video signal supply lines VSIG 1  to VSIG N  in a manner such that they are thinned as shown in  FIGS. 9B ,  9 C,  9 D,  9 E,  9 F,  9 G 
   Accordingly, in the liquid crystal drive system  1 , the number of outputs pins of the Post Driver  4  of the liquid crystal panel module  9 R, the number of video signal supply lines VSIG N  physically wired and the number of switches SW&lt;SUB&gt;N&lt;/SUB&gt; prepared at the group of signal line select switches  14  are designed so as to comply with the highest definition display format, e.g., Full HD to thereby adjust the number of developments of analog video signals of p-phase delivered from the Pre Driver  3  by the Post Driver  4  even in the case where liquid crystal panel of any display format is used thus to have ability to flexibly cope with such situation only by simple adjustment to suitably change timing pulse, etc. by the DSD2. 
   Further, the video signal which has been developed at the Post Driver  4  and has been delivered to video signal supply lines VSIG 1  to VSIG N  is delivered to respective switches SW N  that the group of signal line select switches  14  has. The video signal thus obtained is delivered to the signal line  22  that each switch SW N  selects every time timing pulse S 1  is delivered, and is written into pixels  23  on the gate line  21  selected by the vertical drive circuit  12 . 
   For example, assuming that the number of signal lines  22  to be selected by the switch SW N  is six, video signals are simultaneously written with respect to pixels arranged at interval of five pixels from pixel of the left end as shown in  FIG. 10A  at a first timing, and video signals are sequentially written into pixel adjacent at the right side as shown in  FIGS. 10B ,  10 C,  10 D,  10 E,  10 F at the subsequent timings. 
   In this case, the region of cross lines indicated at a in  FIG. 10  indicates pixel which has been already written, and the region of slanting lines indicated at b indicates pixel which has been newly written. 
   Accordingly, in the signal line select sampling system, since pixels to be written at the same timing are not adjacent to each other so that they maintain a predetermined pixel spacing, there is no possibility that even in the case where the phase relationship between video signal and timing pulse deviates, this affects other pixels. Namely, it is possible to completely remove occurrence cause of ghost taking place resulting from the fact that, as in the case of the plural pixel simultaneous sampling system, in the case where phase relationship between video signal and timing pulse deviates, video signal is inserted (written) also except for video signals which are primarily to be written. 
   While explanation has been given in the above-described explanation by using the Pre Driver  3 , the Post Driver  4  and the liquid crystal panel  9 R, the signal line select sampling system is executed in entirely the same manner also in the case of the liquid crystal panel  9 G driven by the Pre Driver  5  and the Post Driver  6  and/or the liquid crystal panel  9 B driven by the Pre Driver  7  and the Post Driver  8 . 
   As stated above, in the signal line select sampling system executed by the liquid crystal panel drive system  1 , since the number of pixels which can be written at a time is greatly increased to a degree, e.g., from six to 100 pixels or more as compared to the plural simultaneous sampling system carried out as the prior art, it is possible to ensure write time which is larger than two times or more. For this reason, stable write operation is performed. 
   In addition, it is possible to comply with liquid crystal panels of various display formats by the same system configuration without performing change of IC, etc. Particularly, in SXGA+, UXGA, Full HD of high resolution, it becomes possible to greatly simplify the system configuration. 
   It is to be noted that whole the present invention has been described in accordance with preferred embodiments thereof in the accompanying drawings and described in detail, it should be understood by those ordinarily skilled in the art that the invention is not limited to embodiments, but various modifications, alternative constructions or equivalents can be implemented without departing from the scope and the spirit of the present invention as set forth by appended claims.