Liquid Crystal Display Counter Electrode Pad Angle Optimization
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Solution Overview
Problem
Liquid crystal display devices with longitudinal electrical field mode suffer from significant rubbing streaks on the alignment film due to the interaction between the rubbing roller and the protruding pad portions of the counter electrode, which affects the display quality.
Innovation Solution
The pad portions of the counter electrode are designed to protrude at an angle of 15° to 35° relative to the substrate, reducing the disturbance of the rubbing roller's hairs and dispersing the disturbance points, thereby minimizing the formation of rubbing streaks on the alignment film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If pad portions protrude from the counter electrode at conventional angles (45° or 90°), then electrical lead-out function is achieved, but rubbing streaks are generated on the alignment film
Solution Approach 1:
The patent changes the geometric parameter of the pad portion by setting the angle between its two sides to a specific range (30°-60°, preferably 45°). This parameter optimization reduces the disturbance to rubbing roller hairs during the rubbing process, thereby minimizing rubbing streaks while preserving the electrical lead-out function
Solution Approach 2:
The pad portion is designed with asymmetric local geometry where the two sides form different angles with the substrate. This local structural optimization creates a configuration that minimizes interference with the rubbing roller while maintaining effective electrical connection, thus reducing rubbing streaks in the specific region where the pad portion contacts the alignment film
2Object-generated harmful factors
If the angle between sides of pad portion is too small or too large, then manufacturing is simplified, but rubbing roller disturbance increases
Solution Approach 1:
The patent establishes an optimal parameter range for the pad portion angle (30°-60°) that balances multiple objectives: minimizing rubbing roller disturbance, reducing rubbing streaks, and maintaining manufacturability. This parameter optimization ensures that the rubbing roller hairs are less disturbed while the angle can be controlled within reasonable manufacturing tolerances
Solution Approach 2:
The pad portion is formed using a transparent conductive film material that combines electrical conductivity with optical transparency. This material selection allows the pad portion to fulfill its electrical lead-out function while being less intrusive to the rubbing process, as the material properties complement the geometric optimization
Data Source
AI summary
A liquid crystal display device includes a first substrate, a second substrate, liquid crystal disposed between the first substrate and the second substrate, an electrode formed over the first substrate, and an alignment film disposed between the electrode and the liquid crystal. The electrode has a pad portion that protrudes from at least part of a side of the electrode and electrically leads out onto the first substrate through a conductive material that is located between the second substrate and the first substrate, and a direction in which at least one side of the pad portion which protrudes from the electrode is set to angle of 15° or more and 35° or less relative to a side of the first substrate which crosses the extended line of the at least one side of the pad portion.