Capacitive Detection Circuit With Variable Frame Timing
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Solution Overview
Problem
Existing detection systems struggle to accurately detect objects at varying distances from the detection surface due to limitations in electrode size and sensitivity, leading to reduced accuracy when objects are close or far from the detection surface.
Innovation Solution
A detecting device with a sensor region and electrodes configured to adjust the frame period for detection based on the relative distance between the sensor and the object, using a detection circuit that integrates and thresholds signal values to optimize detection accuracy across different distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electrode size is increased to enhance sensitivity and expand the detectable range, then the detection sensitivity and range are improved, but the device area and complexity increase
Solution Approach 1:
The patent applies dynamics by making the frame period variable rather than fixed. The detection system dynamically adjusts the frame period based on the detected object's distance from the detection surface. When an object is close to the surface, a shorter frame period is used; when farther away, a longer frame period is employed. This dynamic adjustment optimizes detection sensitivity across different distances without requiring larger electrodes.
Solution Approach 2:
The patent changes the temporal parameter (frame period) to solve the detection sensitivity problem. By varying the frame period according to object distance, the system achieves high detection sensitivity for both near and far objects using the same electrode size, thereby avoiding the need to increase electrode area.
2Measurement precision
If a fixed frame period is used for detection, then the detection process is simple and fast, but detection accuracy varies significantly with object distance
Solution Approach 1:
The patent implements feedback by using the detected capacitance values to determine object distance and subsequently adjusting the frame period for the next detection cycle. The detection circuit measures capacitance, estimates distance based on this measurement, and feeds this information back to control the timing of subsequent detections, creating a closed-loop system that maintains high accuracy across varying distances.
Solution Approach 2:
The patent applies preliminary action by performing distance estimation based on capacitance detection before setting the appropriate frame period for subsequent detection. This preliminary distance assessment allows the system to pre-adjust the detection timing parameters to match the expected object distance, optimizing detection accuracy before the actual measurement occurs.
3Speed
If the frame period is shortened to improve detection speed, then the detection response is faster, but detection accuracy for distant objects deteriorates
Solution Approach 1:
The patent resolves this contradiction through dynamic frame period adjustment. The system automatically selects appropriate frame periods based on real-time distance estimation: shorter periods for nearby objects to maintain fast response, and longer periods for distant objects to ensure sufficient signal accumulation and accuracy. This dynamic behavior eliminates the need to choose between speed and accuracy for different scenarios.
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
The device enhances detection accuracy by adjusting the frame period and integrating signal values, allowing for precise detection of objects regardless of their proximity to the detection surface.
Implementation Method 1
detects a capacitance generated near a detection surface by applying a detection signal to a plurality of electrodes provided in the detection region
Data Source
AI summary
A detecting device includes a sensor region having a detection region, a plurality of electrodes provided to the detection region, and a detection circuit configured to detect an object to be detected on the detection region frame by frame based on a detected value of each of the electrodes. Length of one frame period for detecting the object to be detected on the detection region differs depending on a relative distance between the sensor region and the object to be detected.