Liquid crystal display device
First Claim
1. A liquid crystal display device having a driving circuit unit and a pixel unit formed combinedly which is capable of accepting a digital signal input having a signal level lower than a power source voltage level of a horizontal driving circuit system, comprising:
- pulse generation means for generating a sampling pulse which samples in time series an input digital signal correspondingly to a pixel;
sampling means for sampling said input digital signal in response to said sampling pulse;
level conversion means for converting a digital signal sampled by said sampling means to a signal having a signal level sufficient for subsequent processing;
latch means for means for holding a digital signal converted by said level conversion means, wherein said level conversion means and said latch means comprise a first switch that is connected to a digital data line, a second switch that is connected to said first switch and to a reference voltage, a capacitor that is connected to a connection middle point of said first switch and said second switch, a first inverter connected to the other end of said capacitor, a third switch provided between an input and output of said first inverter and controlled by said level shift pulse, a second inverter connected to the output of said first inverter, and a fourth switch connected in parallel to said first inverter and said second inverter and controlled by a latch pulse; and
D/A conversion means for generating an analog signal based on a digital signal which was level converted by said level conversion means.
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Accused Products
Abstract
A driving circuit combined type LCD which employs sampling system of analog video signals can not be applied to a medium to large sized LCD. To solve this problem, in an active matrix type LCD having a driving circuit unit which is capable of accepting digital signals having the signal level lower than the power source voltage of a horizontal driving circuit system and pixel unit formed combinedly, level shift circuits for converting the level of sampled digital signals having a small amplitude to digital signals having a voltage of 0 to the power source voltage Vd (for example, 12 V) are provided between sampling switches and latch circuits, thus the structure is capable of accepting digital signals having a small signal amplitude from the outside.
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Citations
12 Claims
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1. A liquid crystal display device having a driving circuit unit and a pixel unit formed combinedly which is capable of accepting a digital signal input having a signal level lower than a power source voltage level of a horizontal driving circuit system, comprising:
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pulse generation means for generating a sampling pulse which samples in time series an input digital signal correspondingly to a pixel;
sampling means for sampling said input digital signal in response to said sampling pulse;
level conversion means for converting a digital signal sampled by said sampling means to a signal having a signal level sufficient for subsequent processing;
latch means for means for holding a digital signal converted by said level conversion means, wherein said level conversion means and said latch means comprise a first switch that is connected to a digital data line, a second switch that is connected to said first switch and to a reference voltage, a capacitor that is connected to a connection middle point of said first switch and said second switch, a first inverter connected to the other end of said capacitor, a third switch provided between an input and output of said first inverter and controlled by said level shift pulse, a second inverter connected to the output of said first inverter, and a fourth switch connected in parallel to said first inverter and said second inverter and controlled by a latch pulse; and
D/A conversion means for generating an analog signal based on a digital signal which was level converted by said level conversion means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification