Half-tone Mask Process for LCD Touch Screen Electrode Formation
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Solution Overview
Problem
The existing manufacturing processes for liquid crystal display devices with built-in touch screens are complex, leading to increased costs and reduced efficiency due to the need for multiple masks and processes, which affects the contact efficiency between data and pixel electrodes.
Innovation Solution
The use of low-temperature poly silicon (LTPS) for the lower substrate and a simplified manufacturing process that reduces the number of masks by employing a half-tone mask for forming the second passivation layer and pixel electrode, enhancing contact efficiency and driving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple masks and processes are used for manufacturing, then manufacturing precision can be maintained, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the formation of the second passivation layer and pixel electrode into a single mask process. The pixel electrode pattern is formed simultaneously with the second passivation layer pattern, eliminating the need for separate masking steps. This merging of operations reduces manufacturing process complexity while maintaining the required contact efficiency between data and pixel electrodes.
Solution Approach 2:
The second passivation layer serves multiple functions: it provides electrical insulation, defines the pixel electrode pattern, and facilitates contact between data and pixel electrodes. By making this single layer perform multiple roles, the patent reduces the total number of manufacturing steps and masks required, thereby simplifying the overall manufacturing process while maintaining manufacturing precision.
2Manufacturing precision
If multiple masks and processes are used for manufacturing, then manufacturing precision can be maintained, but productivity decreases
Solution Approach 1:
The patent merges the pixel electrode formation and second passivation layer formation into one simultaneous process step. This reduction in the number of discrete manufacturing steps directly increases productivity by decreasing cycle time and the number of mask alignment operations required, while the integrated design ensures that contact efficiency between electrodes is maintained.
Solution Approach 2:
The pixel electrode pattern is predetermined and formed in advance during the second passivation layer formation process. This preliminary integration of the electrode pattern into the passivation layer structure eliminates subsequent separate electrode formation steps, thereby improving manufacturing efficiency without compromising the precision of electrode contacts.
3Manufacturing precision
If multiple masks and processes are used for manufacturing, then manufacturing precision can be maintained, but manufacturing cost increases
Solution Approach 1:
The patent combines multiple manufacturing operations into a single integrated process step where the second passivation layer and pixel electrode are formed simultaneously using one mask. This merging eliminates the need for additional masks, photoresist materials, and processing equipment time, directly reducing manufacturing costs while preserving the precise contact geometry between data and pixel electrodes.
Solution Approach 2:
The second passivation layer is designed to serve multiple purposes: providing insulation, defining electrode patterns, and enabling electrode contacts. This multi-functionality reduces the total material and process requirements, thereby lowering manufacturing costs while maintaining the precision needed for effective electrode contact.
Data Source
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AI summary
A liquid crystal display device with a built-in touch screen including a substrate having a pixel region, a thin film transistor formed in the pixel region, a first passivation layer formed on the thin film transistor, a first contact hole formed through a portion of the first passivation layer to expose the data electrode, a common electrode formed on at least one portion of the first passivation layer including inside the first contact hole, the common electrode operable to sense touch, a conductive line formed on at least one portion of the first passivation layer including inside the first contact hole, a second passivation layer formed on the common electrode and the conductive line, a second contact hole formed through a portion of the second passivation layer to expose the conductive line corresponding to the data electrode, and a pixel electrode electrically connected with the conductive line, the pixel electrode formed on the second passivation layer and inside the second contact hole, wherein the second passivation layer and the pixel electrode are simultaneously formed by a mask process using a half-tone mask.