IR Touchscreen Beam Splitter for Multiple Touch Detection
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Solution Overview
Problem
Current SAW and IR touchscreen technologies face challenges in accurately pairing X and Y coordinates for multiple touches, especially when touches occur in close proximity, due to limitations in signal detection and processing, leading to ambiguous results and increased size or reduced usability of touchscreens.
Innovation Solution
The implementation of an IR touchscreen system using beam splitters with deflecting elements that split IR beams into undeflected and deflected components, allowing for the detection of a third coordinate (U) without the need for additional transmitters and receivers, thereby improving the accuracy of touch detection and reducing the complexity of the touchscreen design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional transmitters and receivers are added to detect the third coordinate U, then multiple-touch detection accuracy is improved, but device complexity and size increase
Solution Approach 1:
The patent makes existing transmitters and receivers perform multiple functions by introducing beam splitters. The same transmitters generate both X and U beams, and the same receivers detect both X and U coordinates. This eliminates the need for additional components while achieving XYU touchscreen functionality for accurate multiple-touch detection.
Solution Approach 2:
Beam splitters are introduced as intermediary components that divide the beam paths from existing transmitters into X and U directions, and direct beams from receivers to appropriate detection channels. This intermediary mechanism enables coordinate separation and pairing without adding transmitters or receivers.
2Measurement precision
If additional transmitters and receivers are added to detect the third coordinate U, then multiple-touch detection accuracy is improved, but the touchscreen size increases
Solution Approach 1:
The patent makes existing transmitters and receivers perform multiple functions by introducing beam splitters. The same transmitters generate both X and U beams, and the same receivers detect both X and U coordinates. This eliminates the need for additional components while achieving XYU touchscreen functionality for accurate multiple-touch detection.
3Measurement precision
If beam splitters with deflecting elements are used to split IR beams, then coordinate pairing accuracy is improved and device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
Beam splitters are introduced as intermediary components that divide the beam paths from existing transmitters into X and U directions, and direct beams from receivers to appropriate detection channels. This intermediary mechanism enables coordinate separation and pairing without adding transmitters or receivers.
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 solution enhances the accuracy of multiple-touch detection, reduces the size and complexity of the touchscreen, and maintains a larger usable touch area by eliminating the need for additional components and seals, thus addressing the ambiguity in coordinate pairing and design limitations of existing technologies.
Implementation Method 1
an optically transparent member having an input configured to receive light and one or more facets. The member has two sides joined at an angle, the facets of one side send light in an X direction and the facets of the other side send light in a Y direction
Implementation Method 2
an IR transmitter positioned at a first location along a first side of the touchscreen and configured to transmit a first IR beam across a surface of the touchscreen
Implementation Method 3
an IR receiver positioned at a second location along a second side of the touchscreen and configured to receive the first IR beam
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An infrared (IR) touchscreen system for detecting multiple touches comprises a touch area (156). At least one transmitter (152, 154) is positioned proximate to outer edges (157) of the touch area for transmitting first beams in a first direction. At least one beam splitter (162, 164) is positioned proximate to the outer edges of the touch area and is configured to split the first beams into at least second (170) and third (172) beams traveling through the touch area in at least second and third directions, respectively, the second and third directions being different from each other. Receivers (158, 160) positioned proximate to the outer edges of the touch are for receiving the at least second and third beams. At least one transmitter is an IR transmitter and receivers are IR receivers.