Optical Touch Detection Using Beam Disturbance Patterns
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Solution Overview
Problem
Current touch-sensitive technologies face challenges in scaling to larger screen sizes and effectively handling multitouch events, leading to inefficiencies and user frustration due to ambiguities in signal detection and high costs associated with special processing and elements.
Innovation Solution
An optical touch-sensitive device with emitters and detectors arranged along the periphery, using multiplexed optical beams to classify touch events as wanted or unwanted based on shape, size, and context, employing touch event templates to determine active regions and form activity maps for accurate touch event classification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional touch-sensitive technologies are used, then small sized displays function well, but scaling to larger screen sizes results in unacceptably low yields or prohibitively high costs
Solution Approach 1:
The patent replaces mechanical touch sensing mechanisms with an optical sensing system. Optical beams are projected across the display surface, and touch events are detected by measuring disturbances in these optical beams. This substitution eliminates the need for complex mechanical structures that scale poorly, enabling large screen sizes while maintaining manufacturing feasibility and cost-effectiveness.
Solution Approach 2:
The optical sensing system serves multiple functions: it detects touch events, determines touch location, identifies touch type (fingertip, palm, stylus), and distinguishes between wanted and unwanted touches. This multi-functionality is achieved through a unified optical beam projection and detection mechanism that can adapt to various touch scenarios without requiring separate specialized components for each function.
2Measurement precision
If complex signal processing is used to resolve multitouch ambiguities, then touch detection accuracy improves, but computational intensity drives up cost and power consumption
Solution Approach 1:
The system performs preliminary classification of touch events based on optical beam disturbance patterns before full processing. By analyzing the characteristics of disturbed beams (which beams are affected, extent of disturbance), the system can quickly categorize touches as wanted or unwanted, and identify touch types. This preliminary action reduces the computational burden by filtering out unwanted touches early, preventing unnecessary complex processing of clearly spurious signals.
Solution Approach 2:
The patent segments the touch detection process into distinct stages: optical beam disturbance detection, touch type classification based on disturbance patterns, and wanted/unwanted touch determination. This segmentation allows each stage to process only the necessary information at that level, reducing overall computational intensity while maintaining accurate multitouch resolution.
3Ease of operation
If traditional touch technologies are used, then simple touch detection is achieved, but handling of unwanted touches (palm rests, etc.) causes interface inefficiency and user frustration
Solution Approach 1:
The system uses feedback from the optical beam disturbance patterns to distinguish between wanted and unwanted touches. By analyzing which specific beams are disturbed and the nature of the disturbance, the system can determine whether a touch is intentional (fingertip at a specific location) or unintentional (palm rest affecting multiple beams in a characteristic pattern). This feedback mechanism enables real-time differentiation and appropriate handling of different touch types, improving interface efficiency by ignoring unwanted touches while responding to wanted ones.
Solution Approach 2:
The patent applies different handling rules to different types of detected touches based on their local characteristics. Fingertip touches that disturb specific beam patterns are processed as valid input, while palm touches that affect multiple beams in characteristic ways are identified and filtered out. This local quality approach allows the system to optimize its response to each detected touch based on its specific characteristics, effectively managing unwanted touches while maintaining responsiveness to intended user input.
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 efficient classification of touch events on larger screens, reduces costs by linear scaling, and improves multitouch event handling, enhancing user interaction by distinguishing between intended and unintended touches.
Implementation Method 1
An example touch-sensitive device is an optical touch-sensitive device that is able to determine the locations of multiple simultaneous touch events. The optical touch-sensitive device includes multiple emitters and detectors. Each emitter produces optical beams which are received by the detectors.
Implementation Method 2
Touch events disturb the optical beams. Touch event templates are used to determine the actual touch events based on which optical beams have been disturbed.
Data Source
AI summary
An optical touch-sensitive device is able to determine the locations of multiple simultaneous touch events on a surface. The optical touch-sensitive device includes multiple emitters and detectors. Each emitter produces optical beams which are received by the detectors. Touch events on the surface disturb the optical beams received by the detectors. Based on the disturbed beams, a map of the touch activity on the surface is generated. Touch characteristics and touch types for each touch event are determined from the map. By applying the touch characteristics and touch types to contextual information, a machine learned model, or a set of predefined rules, touches can be classified as wanted or unwanted touch events. Unwanted touch events may be ignored to improve user experience.