Electromagnetic Input Device Resolving Glove Interference
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Solution Overview
Problem
Existing input devices for vehicle user interfaces, particularly those using capacitive touch detection, face interference issues from foreign bodies and static charging, leading to unreliable position detection, especially for small changes, and are not functional with gloved fingers, necessitating a more reliable and cost-effective non-contact position detection method.
Innovation Solution
An input device featuring a touchpad with a detection device that generates an alternating electromagnetic field, using an electrical oscillating circuit with an actuating part that varies its resonant frequency based on position, allowing for reliable position-dependent absorption or radiation behavior detection, enabling accurate switching or control functions with reduced susceptibility to interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If capacitive touch detection is used for position detection, then non-contact operation is enabled, but reliability deteriorates due to interference from foreign objects and static electricity
Solution Approach 1:
The patent replaces capacitive touch detection with electromagnetic field-based detection using a transmitter and receiver. The transmitter generates an electromagnetic field that interacts with the actuator, and the receiver detects changes in this field caused by the actuator's position, eliminating the need for capacitive sensing and its associated interference problems.
Solution Approach 2:
The patent introduces an electromagnetic field as an intermediary between the detection device and the actuator. Instead of directly sensing capacitance changes, the system uses electromagnetic field interaction as a mediator to detect position, which provides better immunity to external interference and static electricity.
2Ease of operation
If capacitive detection is used for position detection, then operation without visual control is possible, but measurement precision deteriorates for small position changes
Solution Approach 1:
The patent replaces capacitive sensing with electromagnetic field-based detection that is inherently more sensitive to small position changes. The electromagnetic field interacts with the actuator in a way that produces detectable signal changes even for minor position variations, improving measurement precision while maintaining hands-free operation.
3Ease of operation
If capacitive detection is used, then input device can be operated with bare fingers, but reliability deteriorates when wearing gloves
Solution Approach 1:
The patent replaces capacitive touch detection with electromagnetic field-based detection. Since the system detects position through electromagnetic field interaction rather than capacitance changes, it can operate reliably whether the user is wearing gloves or not, as the electromagnetic field penetrates materials including gloves.
4Ease of operation
If capacitive detection is used for position detection, then non-contact sensing is achieved, but susceptibility to electromagnetic field interference increases
Solution Approach 1:
The patent uses an electromagnetic field as an intermediary that is deliberately designed to be robust against external interference. The field-based detection mechanism can distinguish between changes caused by the actuator and external electromagnetic interference, providing reliable non-contact sensing in challenging electromagnetic environments.
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 more reliable and cost-effective input device with improved operational safety and ease of use, capable of precise position detection and functional reliability, even in the presence of interference, and allows operation with gloved fingers.
Implementation Method 1
a transmitter for generating an alternating electromagnetic field
Implementation Method 2
an electrical resonant circuit arranged in an alternating electromagnetic field
Implementation Method 3
position-dependent absorption behavior or a position-dependent radiation behavior of the resonant circuit
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
The invention relates to an input device (1), comprising a touchpad (3), an actuation part (2) rotatably and/or slidably mounted on the touchpad (3), and a detection apparatus (4, 6, 7) which is arranged on the touchpad (3) and has a transmitting apparatus (6) for producing an electromagnetic alternating field by means of a transmitting signal (9) and a receiving apparatus (7) for receiving the electromagnetic alternating field, a receiving signal (12) thus being produced, and an evaluation unit (5) which is connected to the detection apparatus (4, 6, 7) so as to conduct electricity; an electrical resonant circuit (8) arranged in the electromagnetic field, wherein the actuation part (2) is designed to vary a resonance frequency of the electrical resonant circuit (8) in dependence on position, and the evaluation unit (5) is designed to detect, using at least the receiving signal (12), position-dependent absorption behavior with respect to the electromagnetic alternating field or position-dependent emission behavior of the resonant circuit (8) on the basis of a current induced in the resonant circuit (8), more particularly to detect the resonance frequency therefrom, and to determine therefrom position information regarding the position of the actuation part (2), and wherein the evaluation unit (5) is designed to perform a switching and/or control function of a vehicle component in dependence on the position information.