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D/A converter, D/C conversion method, substrate for liquid crystal display panel and liquid crystal display device

A technology of liquid crystal display device and converter, which is applied in the direction of analog/digital conversion calibration/test, analog/digital conversion, digital-to-analog converter, etc., which can solve problems such as insufficient pre-charging and increased power consumption, and achieve reliability high effect

Inactive Publication Date: 2007-05-16
SEIKO EPSON CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At this time, the precharge is not sufficient, and as a result, its error will be related to the display error of the liquid crystal unit
In addition, the wiring for supplying the precharge voltage needs to be charged and discharged at a high speed, and the power consumption will increase.

Method used

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  • D/A converter, D/C conversion method, substrate for liquid crystal display panel and liquid crystal display device
  • D/A converter, D/C conversion method, substrate for liquid crystal display panel and liquid crystal display device
  • D/A converter, D/C conversion method, substrate for liquid crystal display panel and liquid crystal display device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0309] (a) Features of this embodiment

[0310] Based on the above considerations, in Embodiment 1, a structure is employed to completely prevent the "output inversion phenomenon" of the D / A converter.

[0311] That is, the present embodiment is characterized in that: the capacitance value of the capacitor is designed in advance so that even if all lower bits (i) lower than a certain bit (j) have deviations in capacitance values ​​in the same direction, only this bit (j) is When a deviation of the capacitance value occurs in the opposite direction (ie, the worst case), "reversal of the capacitance value" never occurs.

[0312] FIG. 1 is a diagram showing the configuration of a D / A converter 20 of this embodiment. As shown in the lower side of FIG. 1, the characteristic of this D / A converter 20 is that the "design value" of the capacitance ratio of the conversion capacitors C1 to C6 is set as C1:C2:C3:C4:C5:C6=1 from the beginning. :2:4:8.56:19.02:4 2.27.

[0313] In FIG. 1 ...

Embodiment 2

[0339] In the first embodiment, it is assumed that "the inversion of the output of the D / A converter" is prevented, but it may be designed according to a slightly looser standard depending on the application.

[0340] At this time, if the design criteria are relaxed, as shown in FIG. 5 , assuming that reversal occurs, it is also possible to design as long as the reversal voltage (ΔV) is smaller than the threshold value (Vth).

[0341] Here, a reference called the visual recognition threshold is introduced, and the capacitance value of the conversion capacitor is designed so that the reversal voltage (ΔV) does not exceed the visual recognition threshold. The "visual recognition threshold" is the maximum value of the difference that cannot be recognized by human vision when the output of the D / A converter is used as luminance information to display an image, and it is about 20mV.

[0342] The output (V) of the D / A converter of the capacitance division method shown in FIG. 1 can ...

Embodiment 3

[0361] Next, a liquid crystal display device in which the above-mentioned D / A converter is mounted on a substrate for a liquid crystal panel will be described.

[0362] (a) Liquid crystal display device to summary

[0363] A liquid crystal display device is composed of a backlight 1000, a polarizer 1200, a TFT substrate 1300, a liquid crystal 1400, an opposing substrate (color filter substrate) 1500, and a polarizer 1600, as shown in FIG. 11 , for example. In this embodiment, a driver circuit 1310 is formed on a TFT substrate 1300 .

[0364] As shown in FIG. 12, on a TFT substrate 1300, scanning lines W1 to Wn, signal lines D1 to Dn, pixel portions to TFTs, a scanning line driver circuit 1320, and a signal line driver circuit 1330 are formed. And, as shown in FIG. 13, a liquid crystal 1400 is sealed between a TFT substrate 1300 and an opposing substrate 1500. Reference numerals 1520, 1522 are alignment films.

[0365] (b) Structure of signal line driver circuit

[0366] As...

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Abstract

The invention provides a method and apparatus for generating a precise and stable voltage at a high speed. More specifically, there is provided a D / A converter constructed using capacitors having capacitance values which are properly deviated from binary-weighted (2n) capacitance values. This D / A converter has the feature that even if the ratios among a plurality of actual capacitances (C1-C6) having weighted values are different from the designed values to an extreme degree, the capacitance value of the jth capacitor is always greater than the sum of the capacitance values of the first through (j-1)th capacitors. This ensures that an unwanted reverse change in the output signal of the D / A converter is prevented from occurring. Furthermore, this technique of the invention can be accomplished without having to use an additional circuit such as a compensation circuit, and therefore this technique is easy and inexpensive.

Description

technical field [0001] The present invention relates to a potential generating device, in particular to a D / A converter, a design method of the D / A converter, a signal line precharging method, a signal line precharging circuit, a substrate for a liquid crystal panel and a liquid crystal display device using them. Background technique [0002] Various studies have been made to generate a predetermined potential from a predetermined signal, but conventional techniques have disadvantages such as not being able to obtain a desired potential or requiring a certain amount of time to reach the predetermined potential. Next, specific examples thereof will be given. [0003] (1) When the desired potential cannot be obtained [0004] Capacitors are sometimes used as D / A converters. A D / A converter using a capacitor is superior to a D / A converter using a resistor in terms of low power consumption. As one of the examples of the D / A converter using capacitors, a D / A converter using bi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03M1/66G09G3/36G02F1/133G09G3/20H03M1/06H03M1/10H03M1/74H03M1/76H03M1/80
CPCH03M1/74H03M1/1057G09G2310/027G09G3/3688G09G3/36G09G3/2011G09G3/3614G09G2310/0297H03M1/804H03M1/0692G09G3/3648G09G2310/0248H04M1/0233
Inventor 木村睦
Owner SEIKO EPSON CORP