Liquid crystal driver and liquid crystal display device using the same

Abstract

A liquid crystal driver includes a voltage generator for generating gray scale voltages on the basis of reference voltages, and an output device for selecting one gray scale voltage from the generated gray scale voltages in accordance with display data, for applying inversion/non-inversion control to the selected gray scale voltage with respect to an inversion reference voltage on the basis of the selected gray scale voltage, an AC switching signal and the inversion reference voltage, and for outputting different liquid crystal supply voltages for one and the same display data to a liquid crystal panel.

1. A liquid crystal driver comprising:
 a plurality of output terminals for outputting display voltages to be applied to a liquid crystal display device;    an input terminal for receiving display data corresponding to said plurality of output terminals; and    output means for converting said input display data into said output display voltages;    wherein said output means selects a display voltage level corresponding to one input display data and simultaneously generates two different display voltages from the selected display voltage level so that either one of said two different display voltages can be selected as an output display voltage for each of said output terminals.    
     
     
       2. A liquid crystal driver according to  claim 1 , wherein said two different display voltages are a display voltage higher than a reference voltage and a display voltage lower than the reference voltage. 
     
     
       3. A liquid crystal driver according to  claim 1 , wherein a display voltage to be selected from said two different display voltages is determined on the basis of a signal received from outside the liquid crystal driver. 
     
     
       4. A liquid crystal driver according to  claim 1 , wherein a display voltage to be selected from said two different display voltages is determined on the basis of input information received together with the display data. 
     
     
       5. A liquid crystal driver according to  claim 2 , wherein said two different display voltages are inverted relative to each other so as to be symmetric relative to each other with respect to said reference voltage. 
     
     
       6. A liquid crystal driver according to  claim 2 , wherein one of said two different display voltages is shifted by an amount corresponding to said reference voltage compared with another one of said two different display voltages. 
     
     
       7. A liquid crystal driver according to  claim 1 , wherein said output means includes level-shift means for shifting said output display voltages with respect to said output terminals. 
     
     
       8. A liquid crystal driver according to  claim 1 , wherein a signal obtained by periodically switching between said two different display voltages is outputted at each of said output terminals. 
     
     
       9. A liquid crystal driver according to  claim 2 , wherein during a certain period, a display voltage higher than said reference voltage and a display voltage lower than said reference voltage are respectively supplied to two arbitrary adjacent output terminals. 
     
     
       10. A liquid crystal driver according to  claim 1 , wherein the liquid crystal driver is constituted by one LSI. 
     
     
       11. A liquid crystal display device comprising:
 a liquid crystal panel including pixel portions which are arranged at positions of intersections of a plurality of data lines and a plurality of scanning lines in the form of a matrix;    a scanning driver for successively supplying voltages to said plurality of scanning lines; and    a liquid crystal driver as defined in  claim 1  for receiving display data and supplying display voltages to said plurality of data lines in correspondence to said display data.    
     
     
       12. A liquid crystal display device according to  claim 11 , wherein said scanning driver includes a level-shift circuit for receiving an input signal of a same level as a level of a signal received by said liquid crystal driver, and shifting the level of said input signal to a level allowed to be used in said scanning driver. 
     
     
       13. A liquid crystal driver according to  claim 1 , wherein said output means includes two different-characteristic output amplification circuits for two adjacent output terminals so that said two different display voltages can be selected and outputted by switching connections between two gray scale voltage data generated on the basis of input display data corresponding to said two output terminals and input terminals of said two output amplification circuits, and connections between output terminals of said two output amplification circuits and said two output terminals on the basis of an external signal. 
     
     
       14. A liquid crystal driver according to  claim 1 , wherein said output means includes a combination of a non-inversion output amplification circuit and an inversion output amplification circuit for two adjacent output terminals so that said two different display voltages can be alternately outputted by alternately switching connections between two gray scale voltage data generated on the basis of input display data corresponding to said two output terminals and input terminals of said combination of output amplification circuits, and connections between output terminals of said combination of output amplification circuits and said two output terminals on the basis of an external signal. 
     
     
       15. A liquid crystal driver according to  claim 9 , wherein said output means includes connection means which connects together two adjacent output terminals outputting a display voltage higher than said reference voltage and a display voltage lower than said reference voltage so that said two adjacent output terminals are connected together during a predetermined period before output display voltages of the two adjacent output terminals are switched. 
     
     
       16. A method of applying display voltages to a liquid crystal display device, the method comprising the steps of:
 receiving display data corresponding to output terminals which output display voltages;    generating gray scale display voltage levels on the basis of reference voltages;    selecting one of the gray scale display voltage levels for each output terminal in accordance with said display data, the selected gray scale display voltage level being a first display voltage for the output terminal;    supplying an AC switching signal and an inversion reference voltage, said AC switching signal having a polarity which is periodically inverted;    inverting said selected gray scale voltage level with respect to said inversion reference voltage to generate an inverted selected gray scale display voltage level, the inverted selected gray scale display voltage level being a second display voltage for the output terminal, the second display voltage being different from the first display voltage, the first display voltage and the second display voltage being available simultaneously;    selecting one of the first display voltage and the second display voltage in accordance with the AC switching signal as an output display voltage for the output terminal; and    outputting the output display voltage from the output terminal.    
     
     
       17. A display device comprising:
   a display panel having a plurality of pixels arranged corresponding to crossing points of a plurality of data lines and a plurality of scan lines; and        a driver being arranged on a single side of the display panel and connected with the data lines for outputting gray scale voltages corresponding to display data consisting of a plurality bits to the pixels via the data lines;        wherein the driver outputs the gray scale voltages having polarity different from each other to adjacent two data lines;        wherein the driver includes:        a first amplifier for outputting the gray scale voltage having a positive polarity corresponding to the display data to one of the adjacent two data lines;        a second amplifier for outputting the gray scale voltage having a negative polarity corresponding to the display data to an other of the adjacent two data lines; and        a selector for switching an output destination of the positive polarity gray scale voltage output from the first amplifier between the one of the adjacent two data lines and the other of the adjacent two data lines while switching an output destination of the negative polarity gray scale voltage output from the second amplifier between the other of the adjacent two data lines and the one of the adjacent two data lines;        wherein the adjacent two pixels on the display panel connected to the adjacent two data lines having polarity different from each other.     
     
     
       18. The display device according to  claim 17 , wherein a pair of the first amplifier and the second amplifier is shared by the adjacent two data lines. 
     
     
       19. The display device according to  claim 17 , wherein the selector switches the output destination of the positive polarity gray scale voltage output from the first amplifier and also switches the output destination of the negative polarity gray scale voltage output from the second amplifier in accordance with an AC switching signal. 
     
     
       20. The display device according to  claim 17 , wherein the driver further includes:
   a first latch for holding the input display data;        a second latch for collectively holding the display data in the first latch according to a timing signal; and        a selection circuit for selecting one of a plurality of gray scale voltages as the gray scale voltage corresponding to the display data in the second latch.     
     
     
       21. The display device according to  claim 17 , wherein the first amplifier and the second amplifier simultaneously output the positive polarity gray scale voltage and the negative polarity gray scale voltage respectively. 
     
     
       22. The display device according to  claim 17 , wherein the adjacent two pixels on the display panel connected to the adjacent two scan lines have polarity different from each other. 
     
     
       23. A display device comprising:
   a display panel having a plurality of pixels;        a driver being arranged on a single side of the display panel;        wherein the driver has output terminals provided for data lines connected to pixels and outputs gray scale voltages corresponding to display data for each pixel consisting of a plurality of bits to the pixel from the output terminal via the data line, and a polarity of the gray scale voltage output from the output terminal at an odd - numbered position is different from a polarity of the gray scale voltage output from the output terminal at an even - numbered position,        wherein the driver includes:        a first amplifier for outputting a positive polarity gray scale voltage corresponding to the display data to the odd-numbered position output terminal;        a second amplifier for outputting a negative polarity gray scale voltage corresponding to the display data to the even-numbered position output terminal; and        a selector for switching an output destination of the positive polarity gray scale voltage output from the first amplifier between the odd-numbered position output terminal and the even-numbered position output terminals while switching an output destination of the negative polarity gray scale voltage output from the second amplifier between the even-numbered position output terminal and the odd number position output terminal;        wherein the polarity of the voltage of the pixel connected with the odd-numbered position output terminal via the data line is different from the polarity of the voltage of the pixel connected with the even-numbered position output terminal via the data line.     
     
     
       24. The display device according to  claim 23 , wherein a pair of the first amplifier and the second amplifier is shared by the odd-position numbered output terminal and the even-numbered position output terminal adjacent to each other. 
     
     
       25. The display device according to  claim 23 , wherein the selector switches the output destination of the positive polarity gray scale voltage output from the first amplifier and also switches the output destination of the negative polarity gray scale voltage output from the second amplifier in accordance with an AC switching signal. 
     
     
       26. The display device according to  claim 23 , wherein the driver further includes:
   a first latch for holding the input display data;        a second latch for collectively holding the display data in the first latch according to a timing signal; and        a selection circuit for selecting one of a plurality of gray scale voltages as the gray scale voltage corresponding to the display data in the second latch.     
     
     
       27. The display device according to  claim 23 , wherein the first amplifier and the second amplifier simultaneously output the positive polarity gray scale voltage and the negative polarity gray scale voltage respectively. 
     
     
       28. A display device, which inverts polarity of voltage at pixels every row or dot, comprising:
   a display panel having a plurality of pixels arranged corresponding to crossing points of a plurality of data lines and a plurality of scan lines; and        a driver being arranged on a single side of the display panel for outputting gray scale voltages corresponding to display data consisting of a plurality bits to the pixels via the data lines;        wherein the driver includes:        output terminals provided corresponding to the data lines;        amplifiers provided corresponding to the output terminals for outputting the gray scale voltage corresponding to the display data; and        a selector for switching a connection between the amplifier and the output terminal;        wherein the adjacent two amplifiers are shared by the adjacent two output terminals; and        wherein the selector switches the connections between the adjacent two amplifiers and the adjacent two output terminals with each other.     
     
     
       29. The display device according to  claim 28 , wherein the driver further includes:
   a first latch for holding the input display data;        a second latch for collectively holding the display data in the first latch according to a timing signal; and        a selection circuit for selecting one of a plurality of gray scale voltages as the gray scale voltage corresponding to the display data in the second latch;        wherein the amplifier is input with the gray scale voltage from the selection circuit.