Electro-optical Device Light Shielding LDD Region
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Solution Overview
Problem
Active-drive type liquid crystal devices face challenges in maintaining high aperture ratio due to the placement of light shielding structures near the LDD region, which can alter TFT properties and allow light to enter sensitive areas, affecting display quality and contrast.
Innovation Solution
The electro-optical device incorporates a scanning line with light shielding properties, a transistor with a semiconductor layer overlapping the scanning line, and strategically positioned light shielding portions at the channel and LDD regions to block light effectively without compromising transistor properties, enhancing light shielding and aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a contact portion for gate potential is provided adjacently along the LDD region to suppress light entering the LDD region, then light shielding is improved, but TFT property changes occur when the contact portion is disposed too close to the LDD region
Solution Approach 1:
The light shielding function is divided into two separate components: a first light shielding portion (contact portion for gate potential) and a second light shielding portion (light shielding wall). This segmentation allows each component to perform its function independently - the first portion provides electrical connection while the second portion provides light shielding near the LDD region without directly contacting it, thus preventing TFT property changes.
Solution Approach 2:
The second light shielding portion acts as an intermediary element positioned between the light source and the LDD region. It provides light shielding protection without requiring direct contact with the LDD region, thereby preventing the harmful effect of light entry while avoiding the harmful effect of direct contact on TFT properties.
2Object-affected harmful factors
If the contact portion for gate potential is disposed too close to the LDD region to effectively shield light, then light shielding is improved, but aperture ratio decreases
Solution Approach 1:
By segmenting the light shielding function into two portions, the design allows the second light shielding portion to be positioned optimally for light blocking without encroaching on the aperture area. The first light shielding portion can be placed closer to the LDD region while the second portion provides the primary light shielding barrier, enabling better aperture ratio maintenance.
Solution Approach 2:
The solution extends the light shielding approach into a multi-component spatial arrangement rather than relying on a single contact portion. This dimensional expansion allows light shielding to be achieved through coordinated positioning of multiple elements, improving both light blocking effectiveness and aperture ratio.
3Object-affected harmful factors
If light shielding structures are placed near the LDD region to block light effectively, then light shielding is improved, but display quality and contrast are affected due to TFT property changes
Solution Approach 1:
Dividing the light shielding function into two separate portions prevents TFT property changes that would otherwise degrade display quality and contrast. By using the second light shielding portion to block light without direct contact with the LDD region, and the first portion to provide electrical connection, the transistor maintains its proper electrical characteristics while still achieving effective light shielding.
Solution Approach 2:
The second light shielding portion serves as an intermediary that protects the LDD region from light exposure without directly contacting it, thereby preventing TFT property changes that would negatively impact display quality and contrast.
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 configuration effectively shields the LDD regions from light, improving the light shielding properties and achieving a high aperture ratio, thereby enhancing display quality and contrast in liquid crystal devices.
Implementation Method 1
a first light shielding portion at a side of a channel region of the semiconductor layer, the first light shielding portion being electrically coupled to the scanning line, and a second light shielding portion provided at a side of an LDD region of the semiconductor layer
Data Source
AI summary
An electro-optical device includes a scanning line extending along a first direction and having a light shielding property, a transistor having a semiconductor layer extending along the first direction so as to overlap with the scanning line, a contact hole electrically coupled to the scanning line at a side of a channel region of the semiconductor layer, and an opening provided at a side of a first LDD region and a second LDD region of the semiconductor layer.