Evanescent Field Sensor for 2D Touch Detection

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Solution Overview

Problem

Existing sensors for detecting physical contact or proximity are complex and costly to manufacture, often requiring intricate wiring and assembly, and may not effectively detect events in two dimensions or through transparent surfaces without compromising their transparency or adding significant cost and complexity.

Innovation Solution

An evanescent field sensor utilizing a dielectric sheet with transceiver antennas configured to emit and detect mm-wave evanescent waves above its surface, allowing for two-dimensional event detection by measuring changes in the wave field strength, which decays exponentially, and can be used with glass, ceramic, or plastic substrates, enabling detection of events like touch, liquids, and defects without direct contact or complex assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional sensors are used for detecting physical contact or proximity, then detection functionality is achieved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvedetection functionalityVSAvoidwiring and assembly complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines transmission and reception functions into a single transceiver antenna, eliminating the need for separate transmitter and receiver antennas. This merging reduces the number of components and simplifies the overall sensor structure while maintaining full detection functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The transceiver antenna serves multiple functions: it acts as both a transmitter for emitting mm-wave signals and a receiver for detecting reflected waves. This multi-functionality reduces component count and simplifies wiring requirements compared to traditional separate transmitter and receiver systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If traditional sensors are used for detecting physical contact or proximity, then detection functionality is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvedetection functionalityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

By merging transmission and reception into a single transceiver antenna, the patent reduces the number of components that need to be manufactured and assembled, directly lowering manufacturing costs while maintaining detection functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single transceiver antenna performs both transmission and reception tasks, making the system self-sufficient and eliminating the need for additional dedicated receiver components, thereby reducing overall system cost.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If evanescent mm-wave is used above dielectric sheet, then two-dimensional event detection is enabled, but wave strength decays exponentially

Engineering Contradiction:

Improvetwo-dimensional detection capabilityVSAvoidwave strength

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary scanning by having the transceiver antenna emit mm-wave signals in multiple directions across the dielectric sheet surface before a complete detection is required. This preliminary action builds up detection coverage progressively, allowing two-dimensional detection capability while managing energy consumption through systematic scanning rather than simultaneous omnidirectional emission.

Inventive Principle:

Principle #10Preliminary 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

The evanescent field sensor provides efficient and cost-effective two-dimensional event detection, including touch and liquid presence, with reduced manufacturing complexity and no compromise on transparency, using low-cost CMOS antennas and galvanic isolation for accurate localization and data transmission.

Implementation Method 1

emit a wave above the plane surface of the dielectric layer

Methodology Applied

Scientific EffectEvanescent wave:

Implementation Method 2

A strength of the wave may exponentially decay in a direction substantially perpendicular to the plane surface

Methodology Applied

Scientific EffectExponential decay:

Implementation Method 3

detect an event adjacent the plane surface

Methodology Applied

Scientific EffectEvanescent field detection:

Data Source

PatentUS10649585B1Electric field sensor

Publication Date: 2020.05.12 NXP BV

AI summary

An electric field sensor including a dielectric layer having a plane surface, at least one transceiver antenna disposed on one side of the dielectric layer, the at least one transceiver antenna configured to emit a wave above the plane surface of the dielectric layer and detect an event adjacent the plane surface, an integrated circuit coupled to the at least one transceiver antenna.