Touch Sensing Apparatus with Diffusive Light Scattering
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Solution Overview
Problem
Existing touch-sensitive panels with above-surface optical touch systems face challenges in achieving optimal signal-to-noise ratio, detection accuracy, and compactness due to precise alignment requirements of opto-mechanical components, which complicates manufacturing and increases costs.
Innovation Solution
A touch-sensing apparatus with a panel, emitters, and detectors arranged along its perimeter, utilizing diffusive light scattering elements and optical filters to direct light parallel to the touch surface, allowing for improved light coverage and detection accuracy while accommodating variations in component alignment, resulting in a more compact and cost-effective solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If precise alignment of opto-mechanical components is implemented to improve detection accuracy, then detection accuracy is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent changes the optical parameters by introducing diffusive elements that scatter light in multiple directions, transforming the rigid geometric light paths into probabilistic scattering patterns. This parameter change allows the system to tolerate alignment variations while maintaining detection accuracy, as the scattered light still follows detectable paths from emitters to detectors through the touch surface.
Solution Approach 2:
The patent introduces diffusive light scattering elements as intermediary components between the emitters and the touch surface. These intermediaries randomize the light paths, creating a buffer that absorbs alignment variations. The scattered light acts as a mediator that still carries the touch detection signal while being less sensitive to precise component positioning.
2Measurement precision
If precise alignment of opto-mechanical components is implemented to improve detection accuracy, then detection accuracy is improved, but manufacturing cost increases
Solution Approach 1:
By changing the optical interaction mode from direct geometric reflection to diffusive scattering, the system reduces the precision requirements for component manufacturing and assembly. This parameter change enables mass production with standard tolerances, significantly reducing manufacturing costs while maintaining adequate detection accuracy through the statistical properties of light scattering.
Solution Approach 2:
The patent employs inexpensive diffusive elements such as white paint coatings or simple diffusive materials that can be applied during standard manufacturing processes. These cheap optical modifiers replace expensive precision alignment mechanisms, allowing for cost-effective mass production of touch-sensitive panels with acceptable performance.
3Reliability
If optical filters are added to filter visible light, then signal-to-noise ratio is improved, but device complexity increases
Solution Approach 1:
The patent designs the optical filter to serve multiple functions: it blocks visible light from reaching the detectors (reducing noise from display backlight and ambient light), while simultaneously allowing the infrared or other non-visible wavelengths used for touch detection to pass through. This multi-functionality is achieved by selecting filter materials with appropriate spectral transmission characteristics, eliminating the need for additional noise-reduction components.
Solution Approach 2:
The patent changes the wavelength parameter of the emitted light to non-visible ranges (infrared, ultraviolet, or other wavelengths) where natural background noise is minimal.配合 with optical filters that selectively block visible wavelengths, this parameter change achieves high signal-to-noise ratio without requiring complex active noise cancellation systems or multiple detector types.
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 apparatus achieves enhanced signal-to-noise ratio, improved detection accuracy, reduced artifacts, and increased robustness with less complex alignment requirements, leading to a more reliable and cost-effective touch-sensing system.
Implementation Method 1
at least one optical filter arranged outside of the display portion of the touch surface and configured to filter visible light
Implementation Method 2
utilizing diffusive light scattering elements and optical filters to direct light parallel to the touch surface
Implementation Method 3
a plurality of emitters and detectors arranged along a perimeter of the panel and beneath the panel, wherein the emitters are arranged to emit non-visible light
Implementation Method 4
a set of light detectors are also arranged around the periphery of the touch surface to receive light from the set of emitters from above the touch surface
Data Source
AI summary
A touch sensing apparatus is disclosed comprising a panel that defines a touch surface extending in a plane having a normal axis and a back surface opposite the touch surface, a display arranged proximal to the back surface and configured to display an image through a display portion of the touch surface, a plurality of emitters and detectors arranged along a perimeter of the panel and beneath the panel, wherein the emitters are arranged to emit non-visible light and the first and second light directing surfaces are arranged to receive the light and direct the light across the touch surface substantially parallel to the touch surface, wherein the apparatus comprising at least one optical filter arranged outside of the display portion of the touch surface and configured to filter visible light.