Method for detecting state of capacitive touch key

A detection method and capacitive technology, applied in electrical components, electronic switches, pulse technology, etc., can solve the problems of low accuracy, low light transmittance, easy wear and service life of mechanical keys, etc., to eliminate process deviation and improve detection. Accuracy, improve the effect of resistance

CN104935320AInactive Publication Date: 2015-09-23ANYKA (GUANGZHOU) MICROELECTRONICS TECH CO LTD
5 Cites 21 Cited by

Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2015-09-23
Estimated Expiration
Not applicable · inactive patent

Smart Images

  • Figure 1
    Figure 1
Patent Text Reader

Abstract

The invention discloses a method for detecting a state of a capacitive touch key, compares a current count value of a counter with a baseline value, and judges whether the capacitive touch key is effectively touched by analyzing the variable quantity of the current count value relative to the baseline value and time of duration. In addition, when the variable quantity of the current count value relative to the baseline value is larger than a baseline variation threshold and is smaller than a key response threshold, the baseline value needs to be updated, i.e., by setting the baseline variation threshold and the key response threshold, that environment temperature variation influences the baseline value is reflected, thereby updating the baseline value when environment temperature varies, improving a capability of being resistant to interference of environment temperature, and improving detection precision. In addition, the baseline value is not a numerical value set in a unified manner, but varies at any time according to the environment temperature, and thus influence of technological deviations of different chips on detection of the state of the capacitive touch key is also eliminated.
Need to check novelty before this filing date? Find Prior Art

Description

technical field

[0001] The invention relates to the technical field of capacitive touch, and more specifically, to a detection method for the state of a capacitive touch key. Background technique

[0002] The initial mechanical buttons are generally operated by pressing, rotating, etc., and the mechanical buttons are easy to wear and have a short service life, and are gradually replaced by touch buttons. Touch keys mainly include resistive touch keys and capacitive touch keys. Due to the low durability and low light transmittance of resistive touch keys, capacitive touch keys have become the mainstream of touch technology. The use of capacitive touch keys not only has a long service life, but also It has the advantages of greater sensitivity, stability, reliability, etc., but the detection accuracy of the state of the existing capacitive touch key is low. Contents of the invention

[0003] In view of this, the present invention provides a detection method for the state of...

Examples

Embodiment Construction

[0023] As mentioned in the background, the detection accuracy of the state of the existing capacitive touch key is low. The inventors have found through research that the defect is mainly caused by the fact that the state detection of the existing capacitive touch keys is affected by environmental changes and chip process deviations, resulting in low detection accuracy.

[0024] Specifically, the existing capacitive touch button state detection method has a method for measuring the frequency of a relaxation oscillator, that is, a standard comparator and some external resistors are used to form a relaxation oscillator that is continuously charged and discharged, and through the relaxation oscillator. Connect a counter to the output to measure period or frequency. Among them, the counter measures the frequency, that is, calculates the number of cycles of the relaxation oscillator within a fixed time. If the number of cycles measured within a fixed time is less than before, it me...