Optical Touch Tomography for Multi-Touch Resolution
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Solution Overview
Problem
Existing touch-sensitive technologies face challenges in scaling to larger screen sizes and efficiently handling multi-touch events, leading to ambiguities and increased computational complexity, which affects touch resolution and cost-effectiveness.
Innovation Solution
An optical touch-sensitive device that applies a non-linear transform to beam measurements to linearize multi-touch events, using a model based on a transfer function to determine touch locations and attributes, with emitters and detectors positioned along the periphery to efficiently handle larger screens and multiple touch points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional touch-sensitive technologies are used, then they function well for small sized displays, but they do not scale well to larger screen sizes
Solution Approach 1:
The touch-sensitive surface is divided into multiple discrete sensing zones or pixels, each capable of independent touch detection. This segmentation allows the system to scale to larger areas by simply adding more zones rather than increasing the complexity of processing for each unit area, directly resolving the scaling problem described in the contradiction.
2Measurement precision
If technologies require specially processed surface or special elements, then they can detect touch events, but increasing screen size by linear factor N requires N2 times as many special elements
Solution Approach 1:
The optical components (light sources and sensors) are designed to serve multiple functions: they detect touch events, determine touch location, and can potentially detect touch pressure. This multi-functionality reduces the need for separate specialized elements for each function, thereby reducing the overall quantity of special elements required while maintaining comprehensive touch detection capabilities.
3Adaptability or versatility
If technologies are used for multi-touch events, then they can detect multiple touches, but ambiguities in raw detected signals must be resolved in a speedy and computationally efficient manner
Solution Approach 1:
The system pre-processes and organizes raw touch signal data into structured formats that facilitate faster ambiguity resolution. By preparing data structures in advance and implementing efficient algorithms for signal disambiguation, the system can handle multi-touch events speedily without requiring excessive computational resources during the actual touch detection moment.
4Adaptability or versatility
If technologies are used for multi-touch events, then they can detect multiple touches, but if computationally intensive, then this will drive up the cost and power consumption
Solution Approach 1:
The system implements a tiered processing approach where only the necessary portion of computational resources is allocated based on the actual touch scenario. For simple single-touch events, minimal processing is used, while multi-touch events receive additional computational resources as needed. This partial action principle ensures that the system handles multi-touch capability without consistently consuming high power, thereby reducing overall energy usage while maintaining versatility.
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 accurate and efficient detection of multiple touch events on larger screens, improving touch resolution and reducing computational complexity, while maintaining cost-effectiveness by scaling linearly with screen size.
Implementation Method 1
The touch events disturb optical beams propagating across the touch sensitive surface
Data Source
AI summary
An optical touch-sensitive device has the capability to determine touch locations of multiple simultaneous touch events. The touch events disturb optical beams propagating across the touch sensitive surface. With multi-touch events, a single beam can be disturbed by more than one touch event. In one aspect, a non-linear transform is applied to measurements of the optical beams in order to linearize the effects of multiple touch events on a single optical beam. In another aspect, the effect of known touch events (i.e., reference touches) is modeled in advance, and then unknown touch events are determined with respect to the reference touches.