Capacitive Proximity Sensing Circuit for Fault Touch Prevention
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Solution Overview
Problem
Conventional proximity sensors in portable electronic devices have limited sensing ranges, are costly, and affect the aesthetic appearance due to their optical nature, leading to issues with false triggers and increased manufacturing costs.
Innovation Solution
An electronic device utilizing a sensing unit, a simple charge-and-discharge circuit, and a processing unit, where the sensing unit, implemented as a conductive layer, senses touch by periodic charging and discharging to output a voltage, allowing for automatic panel and backlight control without the need for an optical proximity sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional proximity sensor is used to detect user proximity, then the touch panel can be automatically turned off to prevent fault touches, but the sensing range is too small and the cost is high
Solution Approach 1:
The patent replaces the optical proximity sensor with a capacitance-based sensing unit that detects user proximity through capacitance changes. This substitution allows for a larger sensing area while maintaining the ability to prevent fault touches, as the capacitance sensing mechanism is less sensitive to precise positioning compared to optical methods.
Solution Approach 2:
The patent changes the detection parameter from optical signal detection to capacitance detection. By monitoring capacitance changes in the sensing unit, the system can detect user proximity over a larger range and with higher reliability, resolving the contradiction between sensing range and fault touch prevention.
2Reliability
If a conventional proximity sensor is used, then fault touches can be prevented, but the device appearance artistry is affected due to color inconsistency
Solution Approach 1:
The patent replaces the optical proximity sensor with a capacitance-based sensing unit that can be integrated into the housing structure without requiring transparent surfaces. This allows the sensing unit to match the housing color and material, maintaining appearance artistry while preserving fault touch prevention capability.
3Reliability
If a conventional proximity sensor is used, then proximity detection is achieved, but the manufacturing cost increases
Solution Approach 1:
The patent uses a simple capacitance sensing unit that can be implemented with basic conductive materials and circuitry, replacing the expensive optical proximity sensor. This cost-effective approach maintains reliable proximity detection while significantly reducing manufacturing costs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances the sensing range, reduces costs, and maintains a consistent appearance by using a non-optical sensing method, providing improved user convenience and additional functions while automatically controlling touch panels and backlights.
Implementation Method 1
a sensing unit (110) adjacent to the sound output device (140), wherein the sensing unit (110) senses whether receiving a touch from a user
Data Source
AI summary
An electronic device includes a sensing unit, a charge-and-discharge circuit, and a processing circuit. The processing circuit includes a control unit, a detecting unit, a determining unit, and an executing unit. The control unit provides a plurality of periodic pulses to the sensing unit and the charge-and-discharge circuit, such that they are charged and discharged periodically and output a sensing voltage. The sensing unit detects the sensing voltage, and determines a charging time according to the sensing voltage, wherein the charging time is a time at which the sensing voltage reaches a predetermined voltage. The determining unit determines whether to trigger an interrupt request according to the charging time. The executing unit performs a designated application when the interrupt request is received.