Asymmetric Capacitor Detect Areas for Adjacent Finger Separation
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Solution Overview
Problem
Current capacitor detection devices face challenges in accurately distinguishing and detecting two adjacent fingers due to the reduced number of Capacitor Detect Areas (CDAs) per column, leading to errors in signal detection and increased noise sensitivity.
Innovation Solution
The proposed solution involves a capacitor detection device with a configuration of multiple CDA columns, where one column consists of a first area CDA, a second area CDA, and optionally a third area CDA, with the second area CDA being twice or three times larger than the first area CDA, and a semiconductor IC with an operational amplifier and voltage generator to apply driving voltages to the CDAs, enhancing capacitance detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of CDAs per column is reduced, then device complexity and cost are reduced, but measurement precision and reliability of detecting adjacent fingers deteriorate
Solution Approach 1:
The patent applies local quality by creating different CDA area sizes within the same column structure. Specifically, it uses a first CDA with area S1 and a second CDA with area S2 (where S2 > S1), allowing different regions to serve different detection purposes. This enables accurate distinction of adjacent fingers while maintaining a manageable total number of CDAs, thus resolving the contradiction between device complexity and measurement precision.
2Measurement precision
If the number of CDAs is increased to distinguish adjacent fingers, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent uses local quality by implementing CDAs with different areas (S1 and S2) within the column structure. This allows the system to achieve high measurement precision for adjacent finger detection without proportionally increasing the total number of CDAs, as the area differentiation provides additional detection capability within the existing CDA count.
Solution Approach 2:
The patent applies asymmetry by deliberately creating unequal CDA areas within the same column. The first CDA has area S1 while the second CDA has area S2, where S2 is specifically designed to be larger. This asymmetric configuration enables the system to distinguish adjacent fingers more effectively without requiring a symmetric increase in the total number of CDAs across all columns.
3Measurement precision
If larger CDA area is used, then sensitivity to object capacitor improves, but area occupied by detection device increases
Solution Approach 1:
The patent applies local quality by strategically assigning different CDA areas to different positions within the column. The larger area CDA (S2) is placed where maximum sensitivity is needed, while the smaller area CDA (S1) is placed where less sensitivity is required. This localized optimization achieves high overall sensitivity without requiring all CDAs to occupy large areas, thus resolving the contradiction between sensitivity and area occupation.
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 configuration allows for accurate object separation without increasing the number of CDAs, reducing costs, shortening detection time, and improving sensitivity by using all capacitors for charge supply, thereby enhancing the detection of object capacitors.
Implementation Method 1
The voltage when the point P is stabilized by the voltages supplied to the three capacitors is defined as Vp, and the current flowing through Cd by the voltage Vd supplied to the inter-line capacitor Cd is defined as id
Implementation Method 2
according to the Kirchhoff current law, id=iprs+icm
Data Source
AI summary
The present invention reconfigures the Capacitor Detect Area (CDA) constituting two columns to reduce the number of CDAs constituting one column and increase the number of CDAs constituting the other so that object separation operation is possible in the column in which the number of CDAs is increased.