Backlit Resistive Key with Translucent Spacer
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Solution Overview
Problem
Existing control panels with resistive keys in motor vehicles face challenges in backlighting due to the presence of force sensors under the support zone, which prevents the transposition of traditional backlighting methods.
Innovation Solution
A control panel design featuring a translucent spacer between the force sensor and the cover, with a main light source and light collector that injects light into the spacer to produce a backlight beam directed towards the detection zone, allowing for backlit resistive keys with minimal components and reduced space, enabling varied front styles and lower installation costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a traditional backlight source is arranged at the rear of the push-button, then the symbol can be backlit, but the force sensor cannot be properly positioned under the support zone
Solution Approach 1:
The patent introduces a translucent spacer as an intermediary element between the force sensor and the cover. This spacer allows light to pass through while providing a mechanical interface that enables both the force sensor to be positioned at the rear and the symbol to be backlit. The spacer acts as a mediator that resolves the spatial conflict between these two requirements.
Solution Approach 2:
The patent moves the light source from a traditional position directly behind the symbol to a lateral position, and uses the translucent spacer to guide light through the detection zone. This dimensional repositioning allows the light to illuminate the symbol without interfering with the force sensor's position under the support zone.
2Illumination intensity
If transparent inks are used for conductive tracks to enable backlighting, then the symbol can be illuminated, but the reliability for automotive applications is compromised
Solution Approach 1:
The patent separates the backlighting function from the conductive track function. The translucent spacer handles light transmission, while the conductive tracks remain opaque and reliable. This segmentation allows each component to perform its function optimally without compromising reliability.
Solution Approach 2:
The translucent spacer serves as an intermediary that enables backlighting without requiring transparent conductive inks. It transmits light while allowing opaque, reliable conductive tracks to be used underneath, thus resolving the conflict between illumination and reliability.
3Illumination intensity
If multiple separate components are used for backlighting and sensing, then the lighting function can be achieved, but the assembly complexity and installation costs increase
Solution Approach 1:
The patent merges multiple functions into the translucent spacer component. The spacer simultaneously provides mechanical support for the force sensor, transmits light from the lateral source, and defines the detection zone boundaries. This consolidation reduces the number of separate components and simplifies assembly.
Solution Approach 2:
The translucent spacer is designed as a multi-functional component that performs mechanical support, light transmission, and structural definition roles. This universality reduces the overall component count and simplifies both manufacturing and installation processes.
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 enables backlit resistive keys in a compact design with reduced parts, facilitating assembly and offering greater freedom in defining pictograms, while ensuring high reliability and compatibility with automotive applications without using transparent inks.
Implementation Method 1
a light collector which makes it possible to inject the light produced by said main light source into the thickness of the spacer so that the spacer produces a backlight beam directed towards an area to be illuminated of the detection zone
Implementation Method 2
a spacer made of elastically compressible material is mounted between the sensor and the cover so as to take up the mechanical play between the sensor and the cover
Implementation Method 3
a force sensor, or touch sensor, is arranged between the cover and the support, at the rear of the detection zone, so as to produce an electrical control signal when a user exerts sufficient pressing force on the detection area
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a control panel (10) comprising a cover (12) which is provided with at least one detection zone for detecting a tactile pressure, forming a control button (B1), in which a pressure sensor (18) is disposed between the cover (12) and a support (14) behind the detection zone. In addition, a spacer (32), made from an elastically compressible material, is mounted between the sensor (18) and the cover (12), such as to take up the mechanical clearance between the sensor (18) and the cover (12). The panel is characterised in that the spacer (32) is at least partially translucent and in that the control panel (10) comprises at least one main light source (36) and a light collector (38) that can be used to inject the light produced by the main light source (36) into the thickness of the spacer (32), such that the spacer (32) produces a backlighting beam that is directed towards a zone to be illuminated (S1) of the detection zone.