Inductive Haptic Interface with Metallic Layer and Soft Spacer
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Solution Overview
Problem
Existing human-machine interfaces face challenges with reliability and haptic feedback, particularly in environments with varying temperature and humidity, and are often unsuitable for use with gloves, as they are either bulky, expensive, or lack tactile sensation.
Innovation Solution
A human-machine interface device featuring a printed circuit board with inductive coils covered by a metallic layer and a non-metallic soft spacer layer, allowing for absolute position detection and force measurement without a moving metallic target, enabling operation with gloves and providing haptic feedback through structured softness in the spacer layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electro-mechanical contacting potentiometers are used for volume control, then good haptic feeling is achieved, but the interface becomes expensive, unreliable, and bulky
Solution Approach 1:
The patent replaces the mechanical contacting potentiometer system with a capacitive sensing system that uses electrical fields instead of mechanical contact. The capacitive sensor detects finger proximity and position through changes in capacitance, eliminating mechanical wear and contact issues while maintaining control functionality. This substitution resolves the contradiction by providing reliable, maintenance-free operation while keeping the interface compact and cost-effective.
Solution Approach 2:
The patent introduces a capacitive sensing field as an intermediary between the user's finger and the control circuitry. Instead of direct mechanical contact, the capacitive field mediates the interaction by detecting changes in electrical capacitance caused by the proximity and position of the finger. This intermediary approach eliminates the need for mechanical contacts while preserving haptic feedback through simulated resistance and tactile responses.
2Ease of manufacture
If capacitive sensors are used for human-machine interface, then manufacturing cost is reduced and variety of shapes/colors is increased, but haptic feeling is lost and reliability over temperature and humidity deteriorates
Solution Approach 1:
The patent employs parameter changes by using multiple capacitive sensors with different sensing parameters (capacitance, conductance, phase) to detect user input. By monitoring multiple electrical parameters simultaneously and comparing their changes, the system can distinguish between genuine user input and environmental interference from temperature and humidity variations. This multi-parameter approach maintains reliability while preserving the manufacturing advantages of capacitive sensors.
Solution Approach 2:
The patent implements feedback mechanisms where the system continuously monitors capacitance changes from multiple sensors and uses this information to distinguish between user input and environmental effects. The feedback loop analyzes the pattern, magnitude, and timing of capacitance changes to determine whether they result from user interaction or environmental factors like temperature and humidity. This feedback-based discrimination maintains reliability while keeping the interface simple and cost-effective.
3Ease of manufacture
If capacitive touch screens or buttons are used, then manufacturing cost is reduced, but haptic feedback is poor and reliability with gloves deteriorates
Solution Approach 1:
The patent incorporates mechanical vibration principles by providing haptic feedback through controlled vibrations of the touch surface. When a user interacts with the capacitive interface, the system generates tactile vibrations that simulate the feeling of pressing a physical button or slider. This vibration-based haptic feedback maintains the manufacturing advantages of capacitive sensors while providing tangible tactile responses that improve ease of operation, including use with gloves.
4Measurement precision
If linear motion sensor with metallic target is used, then position detection is achieved, but the interface requires moving metallic target and lacks haptic feeling
Solution Approach 1:
The patent replaces the mechanical linear motion sensor with a metallic target system with a capacitive sensing system that detects finger position through capacitance changes. Instead of requiring a physical metallic target to move over coils, the capacitive sensors detect the position and movement of the user's finger directly through electrical field interactions. This substitution maintains precise position detection while enabling natural haptic feedback through the capacitive interface.
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 solution provides a reliable, cost-effective, and haptically responsive interface that functions effectively with gloves, offering precise position detection and force measurement, suitable for various applications including climate control and selection inputs in vehicles and construction equipment.
Implementation Method 1
A human-machine interface device featuring a printed circuit board with inductive coils covered by a metallic layer and a non-metallic soft spacer layer, allowing for absolute position detection
Implementation Method 2
an inductive position sensor integrated circuit on the PCB detects a pressure on a pushed area of the protective coating which results in an inductive voltage indicating the local position of the pushed area
Data Source
Figure 1~2c
Figure 2a~2b
Figure 4a~4b
AI summary
The invention discloses a human-machine interface device. The omnipresent wish to seek for reliable, cost effective solutions of human-machine interfaces that are cheap to manufacture and provide haptic feedback as well will be solved by a human-machine interface device comprising a printed circuit board (PCB) including inductive coils, a metallic layer completely covering the inductive coils, whereas a non-metallic soft layer between the PCB and the metallic layer provides a variable distance between the metallic layer and the inductive coils, and a protective coating stacked on the metallic layer, wherein an inductive position sensor integrated circuit on the PCB detects a pressure on a pushed area of the protective coating which results in an inductive voltage indicating the local position of the pushed area.