Unlock instant, AI-driven research and patent intelligence for your innovation.

Liquid crystal device comprising array of sensor circuits with voltage-dependent capacitor

A sensor circuit, liquid crystal device technology, applied in the direction of instrument, electrical digital data processing, data processing input/output process, etc., can solve problems such as mismatch and low sensitivity, and achieve the effect of reducing manufacturing cost and improving sensitivity

Inactive Publication Date: 2012-07-11
SHARP KK
View PDF7 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

While these structures help increase the sensitivity of capacitive sensors, there is still a mismatch between the capacitive change that a user pressing an input object against the display can comfortably produce and the capacitive change that the sensor can reliably detect
In particular, this low sensitivity when utilizing an input object with a larger contact area (such as a finger) that produces less pressure for a given input force than an input object with a smaller contact area (such as a stylus or pen) still a problem

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Liquid crystal device comprising array of sensor circuits with voltage-dependent capacitor
  • Liquid crystal device comprising array of sensor circuits with voltage-dependent capacitor
  • Liquid crystal device comprising array of sensor circuits with voltage-dependent capacitor

Examples

Experimental program
Comparison scheme
Effect test

no. 1 example

[0095] The first embodiment illustrates the basic concept of utilizing a voltage sensitive select capacitor to increase the sensitivity of the output of an active pixel sensor circuit to changes in liquid crystal capacitance.

[0096] The first embodiment relates to a liquid crystal device including a first array composed of a plurality of first sensor circuits. In this embodiment, each first sensor circuit is an active pixel sensor circuit. Such as Figure 9 As shown in , the active pixel sensor circuit constituting the first sensor circuit of this embodiment includes: a data line DAT; a power supply line VDD; a row selection line RWS; an amplifier M1; component CV; and voltage sensitive selection capacitor C1. The input of the amplifier is connected to the first terminal of the sensing capacitor.

[0097] The second terminals of the sensing capacitors of each first sensor circuit may be connected to the common voltage line VCOM such that the second terminals of the sensin...

no. 2 example

[0122] In a second embodiment of the present invention, the selection capacitor of the first embodiment may be constituted by a second Metal Oxide Semiconductor Field Effect Transistor (MOSFET) such as a Thin Film Transistor (TFT). The transistor may be a p-type transistor with a gate terminal connected to row select line RWS and source and drain terminals together connected to the gate terminal of the amplifier transistor. Figure 14 This configuration is shown in which transistor M2 constitutes a voltage sensitive select capacitor.

[0123] The voltage V between the gate terminal and source terminal of transistor M2 GS less than the threshold voltage of the transistor V T，M2 In the first state of , the transistor is turned on and exhibits a gate-drain capacitance, a gate-source capacitance, and a gate-channel capacitance (C GD，M2 、C GS，M2 and C GC，M2 ) is equal to the sum of capacitance C 1A . The voltage V between the gate terminal and source terminal of transistor M2...

no. 3 example

[0126] In a third embodiment of the present invention, the selection capacitor of the first embodiment may be formed of an n-type transistor. exist Figure 15 In this circuit shown in , the gate terminal of the transistor M2 constituting the selection capacitor is connected to the gate terminal of the amplifier transistor M1, and the source and drain terminals of M2 are connected together to the row selection line RWS. Likewise, this transistor exhibits Figure 10 The desired voltage-capacitance relationship shown in .

[0127] The operation of the circuit is as previously described in relation to the first and second embodiments.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

A liquid crystal device is provided, for example in the form of a combined display and sensor forming a touch screen. The device comprises an array, for example of active matrix type, of sensor circuits. Each sensor circuit comprises a liquid crystal sensing capacitor (CV) connected to a transistor M1 arranged as a source-follower. A sensor selecting capacitor (C1) in the form of a voltage dependent capacitor (variable capacitor) is connected between the transistor (M1) and a row select line (RWS). The capacitance of the voltage dependant capacitor (C1) is dependent on the voltage across it and has a larger value for a small voltage and a smaller value for a large voltage.

Description

technical field [0001] The invention relates to liquid crystal devices, for example for use in the field of active matrix liquid crystal displays (AMLCDs) with integrated sensors. Such a device can be used to sense the change in capacitance of a liquid crystal material when the display is mechanically deformed to generate touch panel functionality based on this measurement. Such a touch panel not only provides information on the location of a touch input event, but also provides information on the force of the touch in relation to the amount of capacitance change through mechanical deformation. Background technique [0002] The circuit for measuring liquid crystal capacitance can be fabricated in a thin film polysilicon process compatible with the thin film polysilicon process used in the fabrication of TFT substrates for AMLCDs. In such systems, the pixel matrix must include both sensor elements and display elements, and the sensor signals are generated by the same liquid ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): G06F3/044G06F3/041
CPCG06F3/044G06F3/0412G06F3/0447G06F3/0446G06F3/0443
Inventor C.J.布朗
Owner SHARP KK