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Touch detection method and detection circuit of capacitance-type touch screen

A capacitive touch screen, touch detection technology, applied in electrical digital data processing, data processing input/output process, instruments, etc., can solve problems such as misjudgment and poor anti-interference performance

Inactive Publication Date: 2010-09-22
SHENZHEN FOCALTECH SYST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These two detection methods can only operate on a single row or a single column at each time, and the interference of the screen is different in each time period, and may treat touch as non-touch, non-touch as touch, or detect coordinates relative to touch point drift, resulting in poor anti-interference performance and misjudgment

Method used

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  • Touch detection method and detection circuit of capacitance-type touch screen
  • Touch detection method and detection circuit of capacitance-type touch screen
  • Touch detection method and detection circuit of capacitance-type touch screen

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Embodiment Construction

[0037] The present invention is aimed at figure 1 In 120, a new detection method for capacitance size is proposed. This detection method can not only detect two rows or two columns at the same time, that is, work in a differential manner, but also detect only one row or one column at a time, that is, a single-ended working mode. If it works in differential mode, then Figure 10Ct1 and Ct2 in , are two rows or two columns of touch capacitors. If operating in single-ended mode, then Figure 10 One of Ct1 and Ct2 is a built-in reference capacitor, and the other is a row or column touch capacitor. Since the implementations of the two modes are basically the same, only the working principle of the differential mode is described here, that is, two rows or two columns are detected at the same time. The specific implementation can be divided into 5 steps: charging, charge sharing, charge difference, sampling and amplification.

[0038] The first step, charging steps:

[0039] Su...

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PUM

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Abstract

The invention discloses a touch detection method and a detection circuit of a capacitance-type touch screen. The touch detection method of the capacitance-type touch screen comprises the following steps: scanning rows and columns of a capacitance matrix of the touch screen, when the rows of the capacitance matrix of the touch screen is scanned, simultaneously scanning two rows or two columns at every time to obtain the capacitance difference value of the two rows or the two columns or scanning one row or one column at every time to obtain the capacitance difference value between the row or the column capacitance and a benchmark capacitance; and processing the obtained capacitance difference value data. The touch detection method creates condition for eliminating the common-mode interference, so the anti-interference capacity of the capacitance touch screen is greatly improved.

Description

[technical field] [0001] The invention relates to a capacitive touch screen, in particular to a touch detection method and a detection circuit of the capacitive touch screen. [Background technique] [0002] figure 1 is a general flow chart of capacitive touch detection, wherein 110 is an equivalent capacitive touch screen. In order to reduce the load on the microprocessor, the capacitive touch screen generally scans in a row-by-row or column-by-column manner, that is, scans one row or one column at a time. In order to characterize the change in capacitance before and after touch, it is necessary to linearly convert the capacitance value of the scanning row or column into a quantity that can be distinguished by an analog circuit, such as time or frequency, and then perform analog-to-digital conversion on this quantity, and send the conversion result to the micro Processor to determine whether there is a touch. [0003] At present, there are two touch detection methods for ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F3/044
CPCG06F3/044G06F3/0446
Inventor 莫良华郭艳
Owner SHENZHEN FOCALTECH SYST
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