Touch Panel Dummy Patterns for Etching Uniformity
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Solution Overview
Problem
Conventional direct on thin film encapsulation touch (DOT) technology experiences uneven etching due to differences in etching rates between metal layers, affecting touch function and reducing production yield.
Innovation Solution
Incorporating dummy patterns in non-functional areas of the first metal layer, which are electrically connected to the second metal layer through via holes, to reduce density differences and improve etching uniformity, while maintaining the touch panel's line switching function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal mesh structure with grid lines is used in DOT technology, then touch signal capture is achieved, but uneven etching occurs due to large density differences between metal layers
Solution Approach 1:
The patent applies local quality by adding dummy patterns specifically in non-functional areas of the first metal layer, creating different structural characteristics in different regions. The functional areas maintain the original metal mesh structure for touch sensing, while non-functional areas incorporate dummy patterns to adjust local density and etching characteristics, thereby achieving uniform etching across the entire structure without compromising touch function.
Solution Approach 2:
The dummy patterns are designed and incorporated into the first metal layer before the etching process. This preliminary structural adjustment ensures that the density distribution is optimized in advance, preventing uneven etching from occurring during the subsequent manufacturing process. The dummy patterns are strategically placed in non-functional areas to prepare the structure for uniform etching without interfering with touch signal capture.
2Manufacturing precision
If dummy patterns are added to the first metal layer, then etching uniformity is improved, but device structure complexity increases
Solution Approach 1:
The dummy patterns are confined to non-functional areas of the first metal layer, leaving the functional touch-sensitive areas unchanged. This localized approach adds structural complexity only where necessary for etching uniformity, without affecting the overall simplicity of the functional design. The dummy patterns serve as a targeted solution rather than a global structural modification.
Solution Approach 2:
The dummy patterns replicate the basic metal layer structure and material composition of the functional areas, using the same metal material and fabrication processes. This copying approach allows the dummy patterns to be integrated into the existing manufacturing workflow without requiring additional complex processes, thereby minimizing the increase in device complexity while achieving the desired etching uniformity.
3Productivity
If dummy patterns are added to non-functional areas, then production yield is increased, but manufacturing process complexity increases
Solution Approach 1:
The dummy patterns are incorporated into the first metal layer during the initial fabrication stages, before the etching process. This preliminary integration allows the etching process to proceed uniformly across the entire structure without requiring additional corrective steps or rework, thereby improving production yield. The dummy patterns are designed to be formed using the same photo-exposure and etching processes as the functional areas, avoiding the need for separate manufacturing steps.
Solution Approach 2:
The dummy patterns modify the local physical parameters (density, mass distribution) of the first metal layer in non-functional areas, which directly affects the etching rate and uniformity. By changing these physical parameters through the addition of dummy patterns, the etching process achieves better uniformity and higher yield without requiring changes to the etching chemistry or process conditions, thereby minimizing manufacturing process complexity.
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 design enhances etching uniformity and touch panel performance, increasing production yield by minimizing the impact of uneven etching and ensuring consistent touch functionality.
Implementation Method 1
the first metal layer is electrically connected to the second metal layer through the via hole
Implementation Method 2
touch signal is captured and identified through mutual capacitance sensed by the grid lines made of metal
Data Source
AI summary
A touch panel and a display device thereof are provided, including a first metal layer, an insulating layer, and a second metal layer. The second metal layer includes a plurality of first metal lines and a plurality of second metal lines, and the first metal lines and the second metal lines are interlaced with each other to form a mesh pattern. The insulating layer is disposed with a via hole, and the first metal layer is electrically connected to the second metal layer through the via hole. A dummy pattern is disposed in a non-functional area of the first metal layer.