Lattice Grating Touch Screen Waveguide Transmission Loss
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Solution Overview
Problem
Existing touch screens, particularly those of large size, face limitations in operation space and efficiency due to high transmission loss and reduced sensitivity, especially when using grating structures for optical waveguides, which affect the precision and cost-effectiveness of non-contact interactions.
Innovation Solution
A grating touch screen based on a lattice structure distribution utilizing a laser light source, an optical waveguide layer, and photoelectric detectors, where the grating is arranged in a lattice pattern to control reflection times and loss efficiency, maximizing the touch screen's efficiency and sensitivity by optimizing the grating period, duty ratio, and coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a grating is arranged on a whole surface of the optical waveguide, then the touch screen can detect touch positions, but large transmission loss occurs reducing light intensity
Solution Approach 1:
The patent divides the grating structure into a lattice pattern with periodic arrangements of grating regions and empty regions, rather than using a continuous grating across the entire waveguide surface. This segmentation reduces the total grating area that causes transmission loss while maintaining sufficient reflection points for touch detection across the display surface.
Solution Approach 2:
The patent applies grating structures only in specific localized regions arranged in a lattice pattern, rather than uniformly across the entire waveguide. The grating parameters (period, depth, width) are optimized for local coupling efficiency while the empty regions preserve high transmission characteristics, creating spatially varying optical properties that balance detection and transmission needs.
2Ease of operation
If display light is reflected by the grating for multiple times, then touch detection is enabled, but the light intensity is obviously reduced
Solution Approach 1:
The patent uses a lattice grating pattern that provides sufficient (but not excessive) reflection points distributed across the waveguide surface. The periodic arrangement ensures enough reflection events occur for reliable touch detection, while the limited grating coverage prevents excessive light loss that would occur with more extensive grating coverage.
Solution Approach 2:
The patent introduces an optical waveguide layer as an intermediary between the display and the grating structure. The waveguide confines and guides the light, allowing multiple internal reflections off the lattice grating while maintaining light intensity through total internal reflection, rather than direct reflection that would cause significant intensity loss.
3Area of stationary object
If the size of the touch screen is increased for larger operation space, then more operation area is provided, but transmission loss increases and sensitivity decreases
Solution Approach 1:
For large-size touch screens, the patent employs a lattice grating pattern that segments the grating structure into periodic units distributed across the entire large area. This ensures uniform touch detection sensitivity across the expanded surface while maintaining low transmission loss through the empty regions of the lattice, allowing large screen size without proportional increase in loss.
Solution Approach 2:
The patent transitions from considering only the two-dimensional display surface to incorporating the third dimension of light propagation within the optical waveguide. The lattice grating creates periodic potential wells that guide light in three dimensions, enabling large-area touch detection by utilizing vertical light confinement and horizontal light guidance simultaneously.
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 provides a larger operation space for large-size touch screens, significantly reduces transmission loss, and enhances sensitivity and efficiency, enabling effective non-contact touch control with improved precision and service life.
Implementation Method 1
after the display light is reflected by the grating for multiple times
Implementation Method 2
the coupling efficiency of the grating to maximize an efficiency of the grating touch screen
Implementation Method 3
a photoelectric detector is arranged on a periphery or two adjacent sides of the optical waveguide layer
Data Source
AI summary
A grating touch screen based on lattice structure distribution comprises a laser light source, an optical waveguide layer, a grating and a photoelectric detector. In the present invention, the grating with the lattice structure distribution is reasonably arranged on the optical waveguide layer, so that the efficiency of detection light from the laser light source reaching the photoelectric detector at a periphery through the grating touch screen is maximized, and the sensitivity of the touch screen is effectively improved.