Ultrasonic Touch Module Using Total Reflection for Large Screens
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Solution Overview
Problem
Capacitive touch screens face high costs due to the use of rare metals like Indium and are limited in size, making them unsuitable for large-scale applications.
Innovation Solution
The development of a touch module using a configuration with a first and second substrate, photosensitive parts, optical current detection lines, spacers, and a third substrate that undergoes total reflection to detect touch inputs, eliminating the need for rare metals and enabling large-size touch screens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ITO (Indium Tin Oxide) is used as the touch electrode material, then the touch screen achieves good touch sensitivity and electrical conductivity, but the manufacturing cost increases due to the use of rare metal Indium
Solution Approach 1:
The patent replaces expensive ITO material with a combination of transparent conductive oxide (TCO) layers and metal particle layers. The metal particle layer (using abundant metals like aluminum or silver particles) provides the necessary conductivity at much lower cost, while the TCO layer maintains transparency and basic conductive properties. This substitution directly addresses the cost issue while preserving touch functionality.
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers: TCO layers (such as IZO, ITO, or FTO) combined with metal particle layers (aluminum, silver, or their oxides). This composite approach leverages the transparency and basic conductivity of TCO materials while using the high conductivity of metal particles to achieve overall electrical performance comparable to or better than pure ITO, at significantly reduced material cost.
2Area of stationary object
If ITO is used to create large-size touch screens, then the coverage area increases, but the material cost and manufacturing difficulty increase significantly
Solution Approach 1:
The patent divides the conductive layer into multiple functional components: a TCO base layer providing transparency and baseline conductivity, and a metal particle layer providing enhanced conductivity. This segmentation allows each layer to be optimized independently and applied using different manufacturing techniques suitable for large-area production, reducing the complexity of manufacturing large-size screens with pure ITO.
Solution Approach 2:
The patent modifies the material composition parameters by transitioning from pure ITO to a composite system with adjustable ratios of TCO to metal particles. This parameter change enables optimization of both electrical conductivity and transparency while using abundant, low-cost materials, making large-size screen production economically viable and technologically feasible.
3Measurement precision
If a multi-layer structure with third substrate and light reflection is implemented, then the touch detection accuracy improves, but the device complexity increases
Solution Approach 1:
The patent introduces a third substrate layer as an intermediary optical element that reflects light back through the touch electrode layers. This intermediary structure enhances the optical path and improves the detection signal without requiring complex active components. The light reflection mechanism provides passive enhancement of touch detection accuracy while maintaining relatively simple device architecture.
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 reduces manufacturing costs and allows for multi-point touch functionality on large-size touch screens without relying on Indium, enhancing touch sensitivity and adaptability.
Implementation Method 1
A light emitted by the light source undergoes a total reflection in the third substrate. When the first spacer is pressed against the third substrate by pressing a location on the second substrate, the light undergoing the total reflection in the third substrate escapes out of the third substrate and irradiates onto the photosensitive part corresponding to the pressed first spacer
Implementation Method 2
the irradiated photosensitive part generates an electrical signal, and a pressed location on the second substrate is determined by detecting the electrical signal transmitted to the optical current detection line electrically connected to the irradiated photosensitive part
Implementation Method 3
A ultrasonic wave emitted by the ultrasonic generator undergoes a total reflection in the third substrate. When a location of the second substrate is pressed to contact a location of the third substrate, a part of the ultrasonic wave undergoing the total reflection in the third substrate escapes out of the third substrate
Implementation Method 4
an intensity of the ultrasonic wave received by the ultrasonic receiver, corresponding to a contacted location on the third substrate, becomes weak, and a pressed location on the second substrate is determined by detecting a condition where the intensity of the ultrasonic wave received by the ultrasonic receiver becomes weak
Data Source
AI summary
In a touch module, a ultrasonic wave emitted by the ultrasonic generator undergoes a total reflection in the third substrate. When a location of the second substrate is pressed to contact a location of the third substrate, a part of the ultrasonic wave undergoing the total reflection in the third substrate escapes out of the third substrate, and an intensity of the ultrasonic wave received by the ultrasonic receiver, corresponding to a contacted location on the third substrate, becomes weak, and a pressed location on the second substrate is determined by detecting a condition where the intensity of the ultrasonic wave received by the ultrasonic receiver becomes weak during loading a touch scan signal in turn on the touch scanning lines.