Capacitive Sensor Terminal Sharing for LED Indication

Solution Overview

Problem

Capacitive proximity sensor devices face challenges in reducing implementation costs and simplifying design without increasing the number of pins required, which affects resource utilization and efficiency.

Innovation Solution

The system and method allow for the sharing of output terminals to both sense capacitance and activate indicating transducers like LEDs, reducing the need for dedicated terminals by configuring driver circuits to apply equal or different electrical potentials for sensing and transducer activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate dedicated terminals are used for activating indicating transducers, then the transducer activation function is reliable, but the number of pins increases and implementation cost increases

Engineering Contradiction:

Improvetransducer activation functionVSAvoidnumber of pins

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The output terminals are designed to serve dual purposes: capacitance sensing and indicating transducer activation. The driver circuits can selectively operate in sensing mode or transducer activation mode, allowing the same physical terminals to perform multiple functions without requiring separate dedicated pins for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the capacitance sensing function and transducer activation function into a single integrated system using shared output terminals. The driver circuits are designed to handle both functions through selective mode operation, merging what would traditionally require separate hardware resources.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If separate dedicated terminals are used for activating indicating transducers, then the transducer activation is reliable, but the implementation cost increases

Engineering Contradiction:

Improvetransducer activation functionVSAvoidimplementation cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The output terminals are designed to serve dual purposes: capacitance sensing and indicating transducer activation. The driver circuits can selectively operate in sensing mode or transducer activation mode, allowing the same physical terminals to perform multiple functions without requiring separate dedicated pins for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the capacitance sensing function and transducer activation function into a single integrated system using shared output terminals. The driver circuits are designed to handle both functions through selective mode operation, merging what would traditionally require separate hardware resources.

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If the same terminals are used for both sensing capacitance and activating transducers, then the number of pins is reduced and cost is reduced, but there may be interference between sensing and transducer activation

Engineering Contradiction:

Improvenumber of pinsVSAvoidsensing accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The driver circuits operate in periodic alternating modes, switching between capacitance sensing mode and transducer activation mode. This time-division multiplexing approach allows the same terminals to be used for both functions while preventing interference, as each function operates during its designated time slot.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The driver circuits are designed to dynamically switch between different operational modes (sensing mode and transducer activation mode). This dynamic reconfiguration allows the system to adapt the terminal usage based on the current operational requirement, ensuring reliable sensing when in sensing mode and reliable transducer activation when in activation mode.

Inventive Principle:

Principle #15Dynamics

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 approach reduces implementation costs by minimizing the number of output terminals required, enabling efficient resource utilization and maintaining accurate capacitance measurements while allowing for transducer activation without impacting sensor performance.

Implementation Method 1

capacitive proximity sensor device... uses capacitive technology to determine the presence, location and/or motion of one or more fingers, styli, and/or other objects

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

indicating transducers, such as light emitting diodes (LEDs)

Methodology Applied

Scientific EffectLight emitting diode: Light Emitting Diode

Data Source

PatentUS8058884B2System and method for measuring a capacitance and selectively activating an indicating transducer

Publication Date: 2011.11.15 SYNAPTICS INC

AI summary

Systems and methods for sensing capacitances that are applicable to proximity sensor devices are provided. The systems and methods provide decreased implementation costs by reducing the number of output terminals required. Specifically, the systems and methods for sensing capacitances provide the ability to selectively activate indicating transducers, such as LEDs, with the same output terminals used for sensing capacitances. This reduces the need for additional, dedicated output terminals for activating the indicating transducers. As such, the system and method provides for efficient use of resources in proximity sensor devices.