Differential detecting capacitance type touch control method and system

Abstract

The invention provides a differential detecting capacitance type touch control system which comprises a detecting circuit, a group of subtracters, a group of programmable gain amplifiers, an analog-digital converter and a demodulating device, wherein the detecting circuit is used for detecting the inducing capacitance of n leads of a capacitance type touch control panel and generating n corresponding induction signals; the subtracters are used for carrying out pairwise subtraction on the n induction signals to generate n-1 differential signals; the programmable gain amplifiers are used for amplifying the n-1 differential signals to generate n-1 amplified differential signals; the analog-digital converter is used for converting the n-1 amplified differential signals into n-1 digital differential signals; and the demodulating device is used for demodulating the n-1 digital differential signals into n-1 digital signals. Meanwhile, the invention also provides a differential detecting capacitance type touch control method. The method and the device can prevent common noise from being amplified by the programmable gain amplifiers and improve the judging accuracy of contact point coordinates.

Description

technical field [0001] The invention relates to the technical field of touch panels, in particular to a method and system for differentially detecting capacitive touch. Background technique [0002] Most modern consumer electronic devices are equipped with touch pads as one of their input devices. In order to meet the needs of lightness, thinness, shortness, and smallness, the touchpad is often integrated with the panel to form a touch panel, which is convenient for users to input. According to different sensing principles, touch panels can be divided into four types: resistive, capacitive, acoustic, and optical. [0003] The technical principle of the touch panel is that when a finger or other medium touches the touch panel, it detects voltage, current, sound waves or infrared rays according to different sensing methods, and then measures the coordinates of the touch point. For example, the resistive type uses the potential difference between the upper and lower electrode...

AI Technical Summary

Problems solved by technology

[0009] When a conductor or a finger approaches or touches the panel, the variation of the mutual inductance capacitance Cm is very small, so it is easily affected by external common noise. After the common noise is amplified by the programmable gain amplifier 120, the overall system performance is reduced. Signal to Noise Ratio (SNR), so the signal D(1)-K~D(n)-K output by the offset device 140 will have a jitter phenomenon due to more noise, which will cause the coordinate judging device The coordinates of the contact points generated by 160 are unstable, or even incorrect

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