Waveguide Touch Detector for Hygienic Contactless Display Input
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Solution Overview
Problem
Current touchscreen technologies face issues such as surface contamination, hygiene concerns, and interference from liquids or non-conductive objects, while augmented reality control methods like voice and gesture recognition have limitations in lighting conditions and require additional devices.
Innovation Solution
A detector system utilizing a transparent waveguide with a diffractive element and decoupling region that allows for contactless input detection by measuring changes in light intensity, enabling interaction with conductive or nonconductive objects and robust performance across various lighting conditions without the need for external databases or devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If touchscreen technology is used for input, then the display surface can be used for direct interaction, but the display surface becomes dirty and hygiene problems occur
Solution Approach 1:
The patent introduces an intermediary optical system consisting of a waveguide with coupling and decoupling gratings. This mediator allows light to be coupled into the waveguide from the front surface and decoupled to sensors at the rear surface, enabling contactless detection of objects approaching the display surface without direct contact being required for input detection
2Adaptability or versatility
If capacitive touchscreen is used, then multi-touch capability is achieved, but conductive objects are required which is awkward when wearing gloves
Solution Approach 1:
The patent replaces the electrical field-based capacitive detection system with an optical detection system. Instead of measuring changes in electrical capacitance caused by conductive objects, the system uses optical gratings to detect the position and presence of objects through light coupling and decoupling, making it insensitive to the electrical conductivity of the input object
3Object-affected harmful factors
If gesture recognition with external sensors is used, then contactless input is achieved, but additional devices and complex systems are required
Solution Approach 1:
The patent merges the display function and the input detection function into a single integrated system. The display surface itself becomes the input interface through the waveguide structure, eliminating the need for separate external sensors or cameras. The coupling and decoupling gratings are integrated into the display assembly, combining multiple functions in one structure
4Object-affected harmful factors
If voice control is used, then contactless input is achieved, but interference from background noise and limited language support occur
Solution Approach 1:
The patent replaces acoustic-based voice recognition with optical-based detection. Instead of processing sound waves that are susceptible to background noise interference, the system uses light interaction with optical gratings to detect object position and gestures, providing more reliable and accurate input detection不受背景噪音影响
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 system provides a contactless, hygienic, and versatile input interface that is resistant to interference and allows for accurate input recognition without surface contamination, offering improved ergonomics and functionality compared to traditional methods.
Implementation Method 1
At least a portion of radiation that is incident on the diffractive element in the display region via the front is deflected by means of the diffractive element
Implementation Method 2
the deflected portion propagates as coupled-in radiation in the base body by reflection (or by reflections) as far as the decoupling region
Implementation Method 3
the decoupling region decouples at least a portion of the coupled-in radiation that is incident on it from the base body
Data Source
AI summary
In a base element of a waveguide for a detector system at least one portion of radiation passing via the front side and impinging on a diffractive element in the display region is deflected via the diffractive element according to the selection region. The deflected portion is propagated as coupled-in radiation via reflection to an out-coupling region and impinges on the associated out-coupling section of the out-coupling region. The portion of radiation coupled out by an out-coupling section impinges on an associated sensor section of the sensor unit, which continuously measures the intensity of the impinging radiation and supplies the control unit, wherein, according to a change of intensity, which is dependent on positioning an object in front of the front side of the base element and in front of a selection region of the display region, the control unit determines whether the one selection region has been selected.