Liquid Crystal Display Manufacturing Process Reduction
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Solution Overview
Problem
The existing manufacturing processes for liquid crystal display devices are complex and costly, with a high number of photomasks required for photolithography, leading to increased production costs and potential defects such as image sticking and irregular transistor characteristics.
Innovation Solution
The process is streamlined by using half-tone exposure technology to reduce the number of photomasks needed, forming pseudo-pixel electrodes and scan lines as laminates, and selectively applying photosensitive organic insulating layers or anodizing source-drain wires to eliminate the need for passivation layers, thereby simplifying the formation of active substrates and reducing manufacturing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography processes are used with multiple photomasks, then manufacturing precision can be maintained, but device complexity and production cost increase significantly
Solution Approach 1:
The patent combines multiple photomask patterns into a single photomask by forming a composite pattern that includes both the pixel electrode pattern and the scan line pattern. This merging of patterns reduces the number of photolithography steps from multiple sequential processes to a single integrated process, thereby simplifying the manufacturing process while maintaining pattern formation precision through careful design of the composite photomask structure.
2Reliability
If conventional passivation layers are formed through multiple heating processes, then transistor characteristics are protected, but production cost and process time increase
Solution Approach 1:
The patent extracts and eliminates the conventional passivation layer formation process by using a different structural approach. Instead of forming separate passivation layers through multiple heating processes, the invention uses the gate insulating layer structure itself to provide the necessary protection and isolation functions, thereby removing the time-consuming passivation steps while maintaining transistor characteristic stability through the inherent properties of the simplified structure.
Solution Approach 2:
The gate insulating layer is designed to serve multiple functions simultaneously: it provides electrical isolation, structural support, and protection against moisture and contaminants that would otherwise require separate passivation layers. This multi-functionality allows the single gate insulating layer to replace multiple specialized layers, reducing the total number of heating processes and cycle time while maintaining the necessary reliability for transistor operation.
3Stability of the object's composition
If excessive heat treatment is applied during manufacturing, then material properties are stabilized, but image sticking defects occur
Solution Approach 1:
The patent changes the thermal processing parameters by reducing both the temperature and duration of heat treatment steps. Instead of applying excessive heat to stabilize material properties, the invention uses optimized lower-temperature processes combined with controlled atmosphere treatment to achieve the same stabilization effect. This parameter optimization prevents the formation of image sticking defects while maintaining material property stability through carefully controlled thermal profiles that avoid overheating the liquid crystal and polarizing layers.
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 approach decreases the number of manufacturing processes, lowers production costs, and enhances the reliability of liquid crystal display devices by reducing defects and maintaining image quality while avoiding excessive heat and complex passivation steps.
Implementation Method 1
selectively applying photosensitive organic insulating layers
Implementation Method 2
anodizing source-drain wires to eliminate the need for passivation layers
Data Source
AI summary
A four-mask process and a three-mask process proposal are constructed for a TN-type liquid crystal display device and an IPS-type liquid crystal device in which the formation of a passivation insulating layer is not required by streamlining the formation of a scan line and a pseudo-pixel element, both comprising a laminate made of a transparent conductive layer and a metal layer, at the same time and the formation of the transparent conductive pixel electrode by removing the metal layer on the pseudo-pixel electrode at the time of the formation of the opening in the gate insulating layer, by streamlining the treatment of the formation process of the contact and the formation process of the protective insulating layer using one photomask due to the introduction of half-tone exposure technology, and the formation of source-drain wires for etch-stop type insulating gate-type transistor using a photosensitive organic insulating layer and leaving the photosensitive organic insulating layer unchanged on source-drain wires or on the source wire (signal line), or by forming an anodized layer, which is an insulating layer, on source-drain wires.