Waveguide Touch Sensing With ToF Imaging for Large-Area Gestures
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Solution Overview
Problem
Existing touch and gesture capturing systems are limited in resolution or range, making them unsuitable for large areas such as typical living spaces, and require a significant distance from the object to be effective.
Innovation Solution
A capturing apparatus utilizing a carrier medium with holographic coupling-in and coupling-out regions, combined with a time-of-flight camera device, allows for large-area detection and precise determination of object location by guiding light through internal reflection, enabling two-dimensional or three-dimensional capturing of objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If point-type sensors or radar sensors are used for large-area detection, then the detection area can be expanded, but the resolution deteriorates and the device complexity increases
Solution Approach 1:
The patent introduces a carrier medium as an intermediary between the light source and sensor device. This carrier medium guides light from a large detection area to a compact sensor device through internal reflection, enabling large-area detection with high resolution without requiring multiple point sensors. The carrier medium acts as the mediator that transfers optical information from the extended detection area to the sensor.
Solution Approach 2:
The patent transitions from point-type sensors (0D/1D detection) to a two-dimensional carrier medium surface that can detect objects across a large area. The carrier medium provides a two-dimensional detection plane while maintaining connection to a compact sensor device, effectively adding spatial dimensionality to the detection capability without proportionally increasing sensor complexity.
2Length of moving object
If conventional optical systems are used for gesture capturing, then the system can be implemented, but the range is limited and the device complexity increases
Solution Approach 1:
The carrier medium serves multiple functions simultaneously: it acts as a light guide, a structural support, and a two-dimensional detection surface. This multi-functionality reduces the need for separate components for each function, thereby simplifying the overall system while extending the detection range and maintaining gesture capturing capability.
Solution Approach 2:
The patent merges the light guiding function and the detection surface function into a single integrated carrier medium structure. By combining these functions that were previously separate in conventional systems, the overall device complexity is reduced while achieving extended detection range for gesture capturing.
3Area of stationary object
If a large distance from the object is maintained for detection, then the detection area can be covered, but the resolution deteriorates
Solution Approach 1:
The carrier medium serves as an optical intermediary that collects light from a large coverage area and guides it to the sensor device with minimal loss. This intermediary structure preserves the spatial information and intensity distribution from the large detection area, enabling precise location determination even when detecting objects across an extended 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
Enables large-area, precise detection of objects with relative location determination, supporting touch and gesture recognition over a wide area without the need for pressure sensors, and allowing integration into transparent surfaces like windows or screens.
Implementation Method 1
The carrier medium is implemented in the form of a light guide, that is to say, the carrier medium represents a light-guiding medium. That is to say, the carrier medium can transmit light, which is coupled into the carrier medium, to the at least one sensor device by internal reflection, preferably total internal reflection.
Implementation Method 2
The coupling-in region is embodied in the form of a holographic element with a first deflection structure. A similar behavior can be seen with regard to a wavelength dependency of the influence of the holographic grating on light. This is because light having a wavelength that is clearly outside the wavelength range specified by the Bragg condition as the so-called Bragg wavelength likewise passes through the holographic grating without being diffracted, and only light having a wavelength that at least approximately satisfies the Bragg condition is diffracted at the holographic grating.
Data Source
AI summary
A carrier medium is designed as a waveguide on which a coupling region and a decoupling region are provided. The coupling region is designed to couple light, which has been emitted from a light source and reflected on an object in the surroundings, into the carrier medium. The coupled reflected light is then transmitted to the decoupling region by internal reflection, and the reflected light is decoupled again at the decoupling region and is transmitted to the at least one sensor device, which is designed as a time-of-flight camera device. The sensor device provides the detected light in the form of sensor data, describing the propagation time of the light reflected on the object, to an analysis device that obtains object data, which describes the position of the object.