LCD Electric Field Distortion Units via TFT Process Merging
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Solution Overview
Problem
The existing liquid crystal display devices, such as TN mode LCDs, suffer from poor contrast ratio and image stability due to varying brightness with viewing angles, and the formation of multi-domains in pixels requires complex fabrication processes, increasing the number of steps and potentially reducing the aperture ratio.
Innovation Solution
The solution involves forming electric field distortion units as stepped portions on the lower substrate during the fabrication of thin film transistors, eliminating the need for additional processes on the upper substrate and allowing for effective multi-domain formation without increasing the number of fabrication steps, thereby enhancing the aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If electric field distortion units are formed by separately depositing dielectric material and patterning conductive material on the upper substrate, then multi-domains can be formed to improve viewing angle stability, but the number of fabrication process steps increases
Solution Approach 1:
The patent merges the formation of the second electric field distortion unit with the existing thin film transistor fabrication process. The dielectric material is deposited together with other TFT dielectric layers, and the conductive material is patterned together with other TFT conductive structures in the same process steps, eliminating separate dedicated processes for the distortion units.
Solution Approach 2:
The fabrication process is designed to serve multiple functions simultaneously. The same dielectric deposition and conductive patterning processes that create TFT structures also create the electric field distortion units, making the process universal and eliminating the need for additional specialized steps.
2Stability of the object's composition
If complex patterning processes are used to form electric field distortion units on the upper substrate, then multi-domain liquid crystal control can be achieved, but the aperture ratio is reduced
Solution Approach 1:
The patent combines the electric field distortion unit formation with the TFT fabrication process, so that the conductive material patterns serve dual purposes as both TFT electrodes and electric field distortion units. This eliminates the need for additional separate patterning that would reduce the aperture ratio.
3Reliability
If additional dielectric material deposition and conductive material patterning are performed on the upper substrate, then second electric field distortion units can be formed, but the fabrication process complexity increases
Solution Approach 1:
The patent merges the formation of the second electric field distortion unit with the existing thin film transistor fabrication process. The dielectric material is deposited together with other TFT dielectric layers, and the conductive material is patterned together with other TFT conductive structures in the same process steps, eliminating separate dedicated processes for the distortion units.
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 simplifies the fabrication process for multi-domains in liquid crystal display devices, improving image stability across a wide range of viewing angles and increasing the aperture ratio by reducing the number of fabrication steps and eliminating the need for complex patterning on the upper substrate.
Implementation Method 1
a liquid crystal director can be oriented when a voltage is applied across the electrodes on the two substrates
Implementation Method 2
at least one first electric field distortion unit in the pixel electrode to control a liquid crystal director by electric field distortion
Data Source
AI summary
A liquid crystal display device includes: a first substrate and a second substrate; a gate line and a data line on the first substrate that cross each other to define a pixel region; a pixel electrode in the pixel region; a thin film transistor at the crossing of the gate and data lines, and connected to the pixel electrode; at least one first electric field distortion unit in the pixel electrode to control a liquid crystal director by electric field distortion; a second electric field distortion unit between the pixel electrode and the first substrate; and a layer of liquid crystal molecules between the first and second substrates.