Optical Switch Prism Cover Transmittance Contradiction
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Solution Overview
Problem
Conventional optical switches with opaque surfaces and low light transmission are unsuitable for reliable operation due to high damping values and interference from extraneous light, and capacitive switches are limited by range and sensitivity to moisture, temperature, and electromagnetic interference.
Innovation Solution
An optical control element with a non-scattering prism and a cover having a high transmittance area for light emission and low transmittance for radiation, combined with a compensation light source and evaluation circuit, allowing for effective detection of object proximity through minimal light reflection changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cover with low light transmission (opaque surface) is used, then aesthetic appearance and radiation protection are improved, but light emission capability deteriorates due to high damping values
Solution Approach 1:
A light guide element is introduced as an intermediary between the light source and the cover. The light guide transmits light from the source to the cover's outer surface, enabling effective light emission while maintaining the cover's opaque aesthetic appearance. The light guide acts as a mediator that decouples the conflicting requirements of opacity and light transmission.
2Object-affected harmful factors
If conventional optical sensors are used with opaque surfaces, then radiation protection is improved, but measurement precision deteriorates due to high damping values
Solution Approach 1:
The light guide serves as an intermediary that channels light from the sensor area to the cover's outer surface. This allows the cover to remain opaque for radiation protection while the light guide maintains optical connectivity between the sensor and the external environment, preserving measurement precision.
Solution Approach 2:
The cover is segmented into different functional areas: a sensor area with higher transmittance for optical detection and a non-sensor area with low transmittance for aesthetic appearance and radiation protection. This segmentation allows simultaneous achievement of radiation protection and measurement precision.
3Measurement precision
If the sensor area is increased to improve detection range, then object detection capability is improved, but interference from extraneous light increases
Solution Approach 1:
Different areas of the cover have different optical properties: the sensor area has higher light transmittance to maximize detection range, while the non-sensor area has low transmittance to block extraneous light. This local differentiation of optical properties resolves the contradiction between detection range and extraneous light interference.
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 enables reliable detection of object proximity with high sensitivity and low basic coupling, overcoming the limitations of conventional optical and capacitive switches by maintaining high sensitivity and reducing interference from ambient light and scattering.
Implementation Method 1
a prism (8) suitable for light conduction... The light transmitter (5) and the receiver (6) are arranged on a second side surface (12) of the prism (8)
Implementation Method 2
optical operating elements in which the reflection of light in the visible or non-visible range, in particular in the infrared range, is used
Implementation Method 3
Photodiodes or photoelements are used as receivers... the received signal of a reflection light barrier depends not only on the degree of reflection to be measured, but also on the ambient light
Data Source
Figure 1a~1b
Figure 1c
Figure 2~3
AI summary
The present invention relates to an optical operating element, more particularly pushbutton or switch, comprising a light-emitting light transmitter, an optical receiver, a prism suitable for guiding light, and comprising a cover, wherein the prism (8) has a side area (12) that is an active sensor area (13), and the prism (8) is arranged below the cover (2) in such a way that the active sensor area (13) of the prism (8) is oriented substantially parallel to the underside of the cover (2). The cover (2) has a sensor region (2a), which is the region of the cover (2) above the active sensor area (13) and which has a transmittance of at most 99%, at most 95%, at most 90%, at most 80% or at most 50%. The prism (8) and the light transmitter (5) are arranged in such a way that light emitted by the light transmitter (5) is guided through the prism (8) and passes through the active sensor area (13) and the cover (2). The receiver (6) is arranged in such a way that the emitted light reflected at an object enters through the sensor region (2a) of the cover (2) and the active sensor area (13) and is guided through the prism (8) to the receiver (6), and a change in reflection is identified by an evaluation circuit and is interpreted as switching.