Exposure Mask with Variable Light Transmittance for LCD Parasitic Capacitance
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Solution Overview
Problem
Conventional LCD manufacturing methods fail to prevent semiconductor patterns like amorphous silicon and impurity-doped patterns from remaining under storage capacitance electrodes, leading to parasitic capacitance and deterioration of image display quality due to flicker and afterimages.
Innovation Solution
A mask with specific light transmitting portions and slits is used to pattern the photoresist film, allowing controlled exposure to light of varying intensities to accurately form the storage electrode and output terminal patterns, ensuring the removal of excess semiconductor material and reducing parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing methods are used to form thin film transistors with masks, then the manufacturing process is simple and fast, but semiconductor patterns remain under the storage capacitance electrode causing parasitic capacitance and image quality deterioration
Solution Approach 1:
The mask is divided into multiple exposing parts (first exposing part, second exposing part, third exposing part) with different light transmittance characteristics. Each exposing part corresponds to different regions (output terminal, adjacent region, storage electrode) and exposes the photoresist film to different light amounts, enabling precise control of semiconductor pattern formation in different areas.
Solution Approach 2:
Different regions of the mask have different light transmittance properties tailored to their specific requirements. The first exposing part has high light transmittance for complete exposure of the output terminal region, the second exposing part has medium transmittance for the adjacent region, and the third exposing part has low transmittance to prevent exposure of the storage electrode region, thereby preventing parasitic capacitance formation.
2Manufacturing precision
If the photoresist film is exposed to uniform light amount, then the exposure process is simple, but semiconductor patterns remain under the storage capacitance electrode leading to parasitic capacitance
Solution Approach 1:
The exposure process is segmented into three distinct exposing parts with different light transmittance characteristics. The first exposing part exposes the photoresist film to a first light amount for the output terminal region, the second exposing part exposes to a second light amount for the adjacent region, and the third exposing part exposes to a third light amount for the storage electrode region, enabling precise differential exposure.
Solution Approach 2:
Each exposing part of the mask is designed with specific light transmittance properties matched to the requirements of its corresponding region. The first exposing part allows maximum light transmission for complete exposure, the second exposing part allows partial transmission for intermediate exposure, and the third exposing part blocks most light to prevent exposure, achieving location-specific exposure control.
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 enhances image display quality by minimizing parasitic capacitance and flicker, resulting in improved image fidelity and reduced afterimages in LCD devices.
Implementation Method 1
A mask with specific light transmitting portions and slits is used to pattern the photoresist film, allowing controlled exposure to light of varying intensities to accurately form the storage electrode and output terminal patterns
Data Source
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AI summary
A mask is provided. The mask includes a mask body, a first exposing part and a second exposing part. The first exposing part is on the mask body. The first exposing part includes a first light transmitting portion and second light transmitting portions. The first light transmitting portion exposes a portion of the photoresist film corresponding to the output terminal to a light of a first light amount. The second light transmitting portions exposes an adjacent portion of the photoresist film adjacent to the output terminal to a light of a second light amount smaller than the first light amount. The second exposing part is on the mask body. The second exposing part includes third light transmitting portions for partially exposing the photoresist film corresponding to the storage electrode to a light of a third light amount that is between the first and second light amounts.