Touch Sensor Layer Structure for Selective ITO Etching
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Solution Overview
Problem
Conventional touch panels face issues with incomplete etching of the second ITO layer due to re-crystallization, leading to short or open circuits and poor touch-sensing functions, as the etching solution cannot effectively pattern the non-crystalline indium tin oxide without damaging the crystalline indium tin oxide layer.
Innovation Solution
An intermediate conductive layer is introduced between the first and second conductive layers of touch sensors, made of transparent conductive materials like tin oxide or zinc oxide, to prevent re-crystallization and ensure complete etching of the second conductive layer without direct contact, thereby isolating the layers and maintaining conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the second ITO layer is made of non-crystalline indium tin oxide to enable selective etching, then the etching process can pattern the second layer without damaging the first crystalline ITO layer, but the non-crystalline ITO layer undergoes re-crystallization during fabrication processes causing incomplete etching and circuit failures
Solution Approach 1:
An intermediate layer is introduced between the first crystalline ITO layer and the second non-crystalline ITO layer. This intermediate layer acts as a mediator that prevents direct contact between the two ITO layers, thereby preventing re-crystallization of the second layer while allowing the etching solution to effectively pattern the second layer without damaging the first layer.
Solution Approach 2:
The conductive structure is segmented into three distinct layers: the first crystalline ITO layer, the intermediate layer, and the second non-crystalline ITO layer. This segmentation isolates the second layer from the first layer, preventing the re-crystallization phenomenon while maintaining the selective etching capability needed for reliable patterning.
2Device complexity
If the first and second ITO layers are made of the same material to simplify the fabrication process, then the manufacturing process becomes simpler, but the etching solution cannot selectively etch the second layer without damaging the first layer
Solution Approach 1:
The intermediate layer serves as a mediator that enables the use of the same ITO material for both first and second layers while still allowing selective etching. By preventing direct contact between the two ITO layers, the intermediate layer allows the etching solution to selectively remove the second layer without affecting the first layer, thus maintaining material simplicity while enabling selective etching.
3Device complexity
If the second ITO layer is directly contacted with the first ITO layer to maintain structural simplicity, then the device structure becomes simpler, but re-crystallization occurs causing short or open circuit issues
Solution Approach 1:
The intermediate layer acts as a mediator that prevents direct contact between the first and second ITO layers, thereby preventing re-crystallization and ensuring circuit reliability. The intermediate layer maintains electrical connectivity while physically isolating the two ITO layers to prevent the re-crystallization phenomenon that causes short or open circuit issues.
Solution Approach 2:
The conductive structure uses a composite material approach by combining different types of ITO layers (crystalline and non-crystalline) with an intermediate layer. This composite structure leverages the properties of each layer: the crystalline first layer provides stable conductivity, the intermediate layer prevents re-crystallization, and the non-crystalline second layer enables selective etching, together ensuring high manufacturing precision and circuit reliability.
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 prevents short-circuits and ensures reliable touch-sensing functions by preventing re-crystallization of the second conductive layer, enhancing the yield and performance of touch panels.
Implementation Method 1
An intermediate conductive layer is disposed between a first conductive layer and a second conductive layer of touch sensors, such that the second conductive layer is not recrystallized
Implementation Method 2
an etching solution, which can only etch the non-crystalline indium tin oxide and cannot etch the crystalline indium tin oxide, is used to etch the non-crystalline indium tin oxide of the second ITO layer
Implementation Method 3
the intermediate conductive layer has conductivity and electrically connects each of the bridge lines with the corresponding second conductive units
Data Source
AI summary
A touch-sensor structure includes a first conductive layer, a second conductive layer, insulating isolation portions, and an intermediate conductive layer. The first conductive layer includes first conductive units, connection lines and second conductive units. Each connection line connects to two first conductive units. The second conductive layer includes bridge lines. Each bridge line is electrically connected to two second conductive units. The insulating isolation portion is disposed between the connection line and the bridge line. The intermediate conductive layer is at least disposed at an overlapping position between the bridge lines and the second conductive units to isolate the first conductive layer from the second conductive layer. The intermediate conductive layer electrically connects each bridge line to the corresponding second conductive units.