Capacitive Touch Switch Reflector Layout for Uniform Illumination
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Solution Overview
Problem
Existing capacitive proximity and touch switches face challenges in providing effective and user-friendly visual feedback for the operating area, particularly in terms of uniform illumination and minimizing interference from electronic light sources.
Innovation Solution
An electrically conductive body with a reflector area is used to deflect light from a laterally arranged light source onto the operating area, ensuring uniform illumination and avoiding interference by positioning the light source offset from the sensor surface, allowing for homogeneous lighting even at low heights and minimizing component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light source is positioned directly over the sensor surface to illuminate the operating area, then the illumination intensity is high, but the electronic light source interferes with the capacitive sensor signal
Solution Approach 1:
The light source is extracted from its conventional position directly over the sensor surface and relocated to a lateral position beside the electrically conductive body. This spatial separation removes the harmful electromagnetic interference from the sensor area while preserving the illumination function through optical redirection via the reflector area.
Solution Approach 2:
The reflector area on the electrically conductive body serves as an intermediary element that redirects light from the laterally positioned light source onto the operating area. This mediator enables the light to reach the sensor surface indirectly, maintaining illumination while avoiding direct placement of the light source over the sensor.
2Object-affected harmful factors
If the light source is positioned laterally offset from the sensor surface, then interference with the sensor signal is minimized, but the illumination uniformity across the operating area deteriorates
Solution Approach 1:
The reflector area is designed with a curved or angled surface geometry that optimizes the redistribution of light from the lateral source. This curved configuration ensures that light rays striking the reflector at different angles are redirected to achieve uniform illumination distribution across the entire operating area, compensating for the offset light source position.
3Volume of moving object
If the distance between the carrier plate and cover plate is reduced to achieve a compact design, then the device size is minimized, but the space available for light emission and reflection is reduced
Solution Approach 1:
The lighting system transitions from a vertical light path (directly over the sensor) to a lateral light path (beside the electrically conductive body). This dimensional change in light propagation allows the system to achieve effective illumination within the constrained vertical space of a compact design, as the light travels horizontally along the reflector area before reaching the operating area.
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 achieves uniform and user-friendly illumination of the operating area while maintaining electrical connectivity and reducing potential interference, enhancing the usability and installation flexibility of capacitive proximity and touch switches.
Implementation Method 1
an electrically conductive body (4) having a reflector area (5) which is designed in such a way that light emitted by the light source (7) is deflectable in the direction of an operating area (2) defined by the sensor surface (2) through the reflector area (5)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a capacitive proximity and/or touch switch, having an electrically conductive body (4) bridging the distance between an at least partially translucent, electrically insulating cover plate (3) and a carrier plate (6), wherein the electrically conductive body (4) has a sensor surface (2) at the end thereof facing the cover plate (3), said sensor surface being connected to an evaluation circuit via the electrically conductive body (4), and wherein a light source (7) is associated with the sensor surface (2), the light of which implementing an optical display in an operating region defined by the sensor surface (2) at the front of the cover plate (3). The light source (7) is disposed at an offset to the position of the operating region, and the electrically conductive body (4) has a reflector region (5) configured such that light emitted from the light source (7) can be deflected in the direction of the operating region by the reflector region (5).