Optical Coupler Beam Reorientation for Multitouch Scalability
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Solution Overview
Problem
Current touch-sensitive technologies face challenges in scaling to larger screen sizes, handling multitouch events efficiently, and meeting increasing resolution demands, often resulting in high costs and low yields due to the need for increased special processing and elements.
Innovation Solution
An optical touch-sensitive device with multiple emitters and detectors coupled through an optical coupler assembly via a waveguide, which can reorient and translate beams to accommodate any orientation or position, and is designed to prevent ambient light interference, allowing for accurate detection of multiple simultaneous touch events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional touch-sensitive technologies are used, then small sized displays can function well, but they do not scale well to larger screen sizes
Solution Approach 1:
The system segments the touch detection function into multiple independent emitters and detectors distributed across the display surface. Each emitter-detector pair operates independently to detect touches in its local region, allowing the system to scale to larger screens without proportionally increasing processing complexity. The segmented architecture enables parallel processing of touch events across different zones.
Solution Approach 2:
The emitters and detectors serve multiple functions: they generate optical beams for touch detection, detect beam interruptions caused by touches, and work collectively to determine touch location through coordinate calculation. This multi-functionality reduces the need for specialized components for each function, simplifying manufacturing while enabling large screen coverage.
2Area of stationary object
If technologies require specially processed surfaces or special elements, then touch detection can be achieved, but increasing screen size by factor N means special processing must be scaled to handle N²
Solution Approach 1:
The optical detection system is divided into multiple discrete emitter-detector pairs positioned at specific locations on the display. Each pair independently performs touch detection in its local field, eliminating the need for continuous special processing across the entire surface. This segmentation reduces manufacturing precision requirements from scaling with area to scaling only with the number of discrete component locations.
Solution Approach 2:
Optical beams serve as intermediaries that travel between emitters and detectors through the display surface. The beams mediate the interaction between the electronic components and the touch surface, allowing touch detection without requiring the surface itself to have complex special properties. The optical medium simplifies the interface between the detection system and the display surface.
3Adaptability or versatility
If multiple touch events occur simultaneously, then multitouch capability is achieved, but ambiguities in raw detected signals must be resolved in a speedy and computationally efficient manner
Solution Approach 1:
The system segments the touch detection space into multiple independent zones, each monitored by specific emitter-detector pairs. When multiple touches occur, each touch is detected by its local segment independently, creating separate signal sets that can be processed in parallel. This segmentation reduces computational complexity by avoiding the need to analyze all possible touch combinations across the entire surface simultaneously.
Solution Approach 2:
The system uses feedback from multiple emitter-detector pairs to resolve ambiguities in multitouch detection. By analyzing the pattern of beam interruptions across all pairs and using iterative calculation methods, the system refines its estimate of touch locations until convergence is achieved. This feedback-based approach efficiently resolves ambiguities even with multiple simultaneous touches.
4Measurement precision
If resolution demands increase, then touch point location accuracy must improve, but this leads to increasing required touch resolution R
Solution Approach 1:
The system performs preliminary actions by pre-positioning multiple emitters and detectors at strategically selected locations across the display surface. This preliminary spatial arrangement creates an optimized geometric configuration that maximizes measurement precision for touch location determination. By establishing this optimal geometry in advance, the system achieves high resolution without requiring excessive numbers of components.
Solution Approach 2:
The system transitions from one-dimensional linear arrays to two-dimensional spatial distributions of emitters and detectors. This dimensional change enables the system to determine touch locations with higher precision by utilizing angular and positional information from multiple directions. The 2D arrangement provides redundant measurement paths that improve accuracy without linearly increasing component count.
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 detection of multiple touch events with high accuracy and reduced computational intensity, effectively addressing the scalability and resolution challenges while minimizing costs and ambient light interference.
Implementation Method 1
multiple emitters and detectors coupled with an optical coupler assembly through a waveguide
Implementation Method 2
the coupler may be configured to reorient beams to accommodate any orientation of emitters and detectors with respect to the waveguide
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
An optical touch-sensitive device is able to determine the locations of multiple simultaneous touch events. The optical touch-sensitive device includes multiple emitters and detectors coupled with an optical coupler assembly through a waveguide on the surface on the optical-touch sensitive device. The coupler may be side coupled or edge coupled to the waveguide. For both the side coupled or edge coupled cases, the coupler may also be configured to reorient beams to accommodate any orientation of emitters and detectors with respect to the waveguide. The coupler may also be configured to translate beams laterally or vertically to accommodate any position of emitters and detectors. The coupler, and touch-sensitive device more generally, are also configured to prevent ambient light entering the waveguide from hitting the emitters and detectors. Each emitter produces optical beams which are received by the detectors. Touch events disturb the optical beams.