IPS-LCD Fabrication Using Impurity-Doped Amorphous Silicon
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Solution Overview
Problem
The existing IPS-LCD devices require multiple mask processes for fabrication, leading to increased production time and cost, which results in degraded display quality due to issues like increased photo current, off current, and wavy noise, affecting the aperture ratio and overall display quality.
Innovation Solution
A method for fabricating a liquid crystal display device that reduces the number of mask processes by forming a gate line, gate electrode, and common line on a substrate, along with a gate insulating layer, active layer, and ohmic contact layers, and then forming data and pixel electrodes to induce an in-plane electric field, while using impurity-doped amorphous silicon patterns to minimize voltage drop and prevent corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple mask processes are used for fabrication, then the fabrication precision can be maintained, but the production time and cost increase
Solution Approach 1:
The patent combines multiple mask processes into a single mask process by designing a unified pattern structure that forms the gate line, gate electrode, and common line simultaneously. This merging of processes reduces production time and steps while maintaining fabrication precision through careful pattern design and material selection.
Solution Approach 2:
The patent creates a multi-functional pattern structure that serves multiple purposes: forming the gate line, gate electrode, and common line all in one process. This universal structure eliminates the need for separate mask processes for each component, thereby reducing production time without compromising precision.
2Manufacturing precision
If multiple mask processes are used for fabrication, then the fabrication precision can be maintained, but the production cost increases
Solution Approach 1:
By merging multiple mask processes into one, the patent reduces material consumption, equipment usage time, and labor costs associated with multiple sequential processes. The unified pattern structure achieves the same fabrication precision with fewer process steps, directly lowering production cost.
Solution Approach 2:
The patent extracts and eliminates redundant mask processes from the fabrication sequence, keeping only the essential single mask process that can achieve the required precision. This extraction of unnecessary steps reduces both time and cost while maintaining the core fabrication quality.
3Manufacturing precision
If the aperture ratio is increased, then the display quality is improved, but the photo current and off current increase
Solution Approach 1:
The patent applies different material properties and structural characteristics to different regions of the device. The impurity-doped amorphous silicon is selectively positioned in areas where it can suppress photo current and off current while allowing the aperture ratio to be maximized in the display region. This local optimization resolves the contradiction between aperture ratio and current control.
Solution Approach 2:
The patent changes the electrical parameters of specific regions by introducing impurity-doped amorphous silicon with controlled doping levels. This parameter modification allows the aperture ratio to be increased in the display area while maintaining low photo current and off current through the doped regions that act as electrical barriers.
4Manufacturing precision
If the aperture ratio is increased, then the display quality is improved, but wavy noise occurs
Solution Approach 1:
The patent introduces impurity-doped amorphous silicon in specific locations to suppress wavy noise while maintaining the high aperture ratio in the display region. The doped regions are strategically positioned to act as noise barriers without interfering with the light transmission area, thus locally addressing the noise problem while preserving overall display quality.
Solution Approach 2:
The impurity-doped amorphous silicon acts as an intermediary element that mediates between the high aperture ratio structure and the wavy noise suppression requirement. It provides a functional buffer that blocks noise propagation while allowing the aperture to remain large for high display quality.
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 reduces the number of mask processes to three, minimizing photo current and off current, preventing wavy noise, and enhancing the aperture ratio, thereby improving the display quality and reducing production costs.
Implementation Method 1
an impurity-doped amorphous silicon pattern contacting the gate insulating layer therebelow, outer sides of the first and second ohmic contact layers being outside the active layer
Implementation Method 2
forming a pixel electrode and a common electrode in the pixel region to induce an in-plane electric field
Data Source
AI summary
A method of fabricating an LCD device includes forming a gate line, a gate electrode, a gate pad electrode at an end of the gate line, and a common line on a substrate; forming a gate insulating layer on the gate electrode; forming an active layer on the gate insulating layer; forming an etch stopper on the active layer; forming first and second ohmic contact layers spaced apart from each other on the active layer and an impurity-doped amorphous silicon pattern contacting the gate insulating layer therebelow, outer sides of the first and second ohmic contact layers being outside the active layer; forming a data line crossing the gate line to define a pixel region, a data pad electrode at an end of the data line, and source and drain electrodes on the first and second ohmic contact layers, respectively; forming a pixel electrode and a common electrode in the pixel region to induce an in-plane electric field; and forming a gate pad terminal electrode on the gate pad electrode. At least one of the data line, the pixel electrode and the common electrode contacts the impurity-doped amorphous silicon pattern therebelow.