Optical Touch Detection Using Beam Modulation Analysis
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Solution Overview
Problem
Conventional touch-sensitive devices struggle to accurately detect multiple simultaneous touch events due to ambiguity in beam intersections, leading to potential false touch points and high resource requirements for processing and storage.
Innovation Solution
A method that involves detecting modulation in optical beam paths, assigning candidate touch points based on modulated beams, and analyzing nearby beams to determine actual touch points, using weighted values for proximity and angle, and clustering to resolve ambiguity, thereby reducing processing power and storage needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an orthogonal grid of beams is used to detect touch points, then the device can determine touch location, but it cannot accurately detect multiple simultaneous touch events due to beam intersection ambiguity
Solution Approach 1:
The patent segments the beam detection process by analyzing individual beam interruptions separately and then combining the results through coordinate mapping. Each beam interruption is processed independently to generate candidate touch points, which are then validated by checking consistency across multiple beams. This segmentation allows the system to handle multiple simultaneous touch events by treating each as a separate detection problem that can be resolved through coordinate intersection analysis.
Solution Approach 2:
The patent introduces an intermediary coordinate mapping process that transforms beam interruption data into candidate touch point coordinates. This intermediary step involves creating a mapping between beam pairs and their intersection points, which serves as a mediator to resolve the ambiguity of multiple touches. The mapping allows the system to distinguish between true touch points and false intersections by analyzing the consistency of coordinate assignments across different beam pairs.
2Measurement precision
If large numbers of emitters and detectors are used to improve resolution, then touch location precision increases, but device complexity and resource requirements increase
Solution Approach 1:
The patent applies partial action by using a limited subset of beam pairs to detect touch points rather than requiring all possible beam combinations. The system identifies sufficient beam interruptions to determine touch location without needing to process every possible beam intersection. This approach achieves adequate resolution with fewer emitters and detectors by focusing computational resources on the most relevant beam pairs for each detected touch event.
Solution Approach 2:
The patent changes the parameter of beam utilization by dynamically selecting which beam pairs to analyze based on detected interruptions. Rather than continuously monitoring all beam intersections, the system adjusts its analysis to focus on beam pairs that show modulation or interruption signals. This parameter change allows the device to maintain high resolution with fewer physical components by intelligently selecting which beams to process at any given moment.
3Measurement precision
If beam scanning is performed to determine touch position, then touch location can be identified, but processing time and resource consumption increase
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing the mapping between beam pairs and their intersection coordinates before actual touch detection occurs. This pre-computed mapping is stored in memory and reused during touch events, eliminating the need to perform complex geometric calculations in real-time. The preliminary preparation of coordinate mappings significantly reduces processing time during actual touch detection while maintaining accurate position determination.
Solution Approach 2:
The patent applies skipping by directly jumping to the analysis of only those beam pairs that show interruption signals, rather than systematically scanning all possible beam combinations. When a touch event is detected, the system rushes through the validation process by immediately checking the pre-computed coordinate mappings for the affected beam pairs, skipping unnecessary calculations for beams that are not interrupted. This selective processing dramatically reduces the time required to determine touch position.
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
This approach enables high-resolution, multi-touch capability with reduced resource usage, eliminating false touch points and providing accurate touch point detection without the need for expensive optical sensors.
Implementation Method 1
optical emitters and detectors defining therebetween a plurality of optical beam paths
Implementation Method 2
an object which is not optically transparent at the wavelength in use will attenuate or interrupt the beams passing through the object location
Data Source
Figure 1
Figure 2a~2b
Figure 3~4
AI summary
A touch sensitive optical control device comprising a set of light emitters 14, 22 and light detectors 18, 24 arranged relative to a touchable surface 30 such that light transmitted by the emitters is received by the detectors along multiple intersecting beams which pass transversely of the surface and touching the surface at a beam interrupts the light transmitted along the beam. Candidate touch points T1, T2, F1, F2 are defined at the intersections of interrupted beams and are confirmed or not as actual touch points by examining test beams 40, 42, 54, 56 near to or coincident with the candidate touch point.