Capacitance Measuring Circuit With Shared Antenna Electrodes

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Solution Overview

Problem

Existing capacitance touch pads and antennas in devices face interference issues due to shared electrical signals, requiring shielding or separate locations, which can limit their operational efficiency and flexibility.

Innovation Solution

A capacitance measuring circuit with a high pass filter and comparator circuit is integrated, allowing for simultaneous capacitance measurement and wireless signal transmission using a set of electrodes, with the high pass filter directing signals based on frequency to prevent interference and enable dual functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If shielding material or separate locations are used to prevent interference between antenna and touch pad, then interference is reduced, but device complexity and space requirements increase

Engineering Contradiction:

Improvesignal interference reductionVSAvoidshielding structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the antenna and touch pad electrodes into a single shared electrode structure, eliminating the need for separate locations or shielding material. The same electrodes perform both wireless signal transmission and capacitance sensing functions, resolving the contradiction by merging previously separate components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The electrodes are designed to serve multiple functions: they act as both antenna elements for wireless communication and as sensing electrodes for touch pad operation. This multi-functionality eliminates the need for dedicated shielding structures or separate component locations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If shielding material is used to separate antenna and touch pad signals, then signal interference is minimized, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvesignal interference reductionVSAvoidmanufacturing simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

By merging the antenna and touch pad into a single electrode structure, the patent eliminates the need for additional shielding materials and complex assembly processes, thereby simplifying manufacturing while maintaining signal integrity through frequency-based separation.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If antenna is placed beneath touch pad with special structures, then limited interference is achieved, but operational flexibility and efficiency are reduced

Engineering Contradiction:

Improveinterference limitationVSAvoidoperational flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic time-division multiplexing where the electrodes switch between capacitance sensing mode and wireless transmission mode based on operational requirements. This dynamic operation provides flexibility in adapting to different functional states while maintaining signal integrity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs periodic switching between sensing and transmission operations, with the electrodes alternately performing capacitance measurement and wireless signal transmission. This periodic action allows both functions to operate with minimal interference while maintaining operational flexibility.

Inventive Principle:

Principle #19Periodic action

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 allows for efficient capacitance sensing and wireless communication without interference, enhancing the operational efficiency and flexibility of devices by distinguishing between capacitance measurement and wireless transmission signals based on frequency.

Implementation Method 1

a high pass filter with a cutoff frequency incorporated into the capacitance measuring circuit. The capacitance measuring circuit may be configured to transmit a wireless signal when the capacitance measuring circuit receives a voltage signal with a frequency greater than the cutoff frequency of the high pass filter

Methodology Applied

Scientific EffectFrequency filtering: Filter (electronic)

Implementation Method 2

the capacitance measuring circuit may be configured to transmit a wireless signal

Methodology Applied

Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 3

The device may include a comparator circuit incorporated into the capacitance measuring circuit. The comparator circuit may distinguish between a capacitance measurement signal and a wireless transmission signal from the capacitance measuring circuit

Methodology Applied

Scientific EffectSignal comparison:

Data Source

PatentUS11983373B1Filter in a capacitance measuring circuit

Publication Date: 2024.05.14 CIRQUE CORP

AI summary

A device may include a first set of electrodes, a second set of electrodes that is transverse the first set, and at least one connection between an electrode in the first set to an electrode in the second set by a high pass filter. The connected electrode(s) in the first set and the connected electrode(s) in the second set may form an antenna. The device may include a processor and memory. The memory may store programmed instructions which cause the processor, when executed, to transmit a wireless signal using the connected electrodes during a first time, and measure a capacitance signal using electrodes in the first set and electrodes in the second set during a second time.