Electro-optic Device Pixel Electrode Overhang Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid crystal devices face limitations in thinning the insulating film thickness due to exposure of cavities, which disrupts liquid crystal alignment and reduces effective voltage, limiting the quality of display.
Innovation Solution
The electro-optic device features a pixel electrode with a concave portion corresponding to the contact hole, where the film thickness increases towards the surface, allowing for a smaller opening area that can be easily covered by a second insulating film, reducing cavity size and apex position, and incorporating a dielectric multilayer film for enhanced reflectivity and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the insulating film thickness is reduced using a polishing process, then the display quality is improved by reducing the distance between electrodes, but the cavity becomes exposed which disrupts liquid crystal alignment
Solution Approach 1:
The pixel electrode is formed with an overhang structure that protrudes over the contact hole opening before the insulating film is deposited. This preliminary action creates a protective barrier that prevents the cavity from being exposed during subsequent polishing processes, thereby maintaining liquid crystal alignment while allowing the insulating film to be thinned for improved display quality
Solution Approach 2:
The pixel electrode is designed with non-uniform thickness, being thicker at the edges forming the overhang and thinner in the center. This local quality variation allows the electrode to provide both electrical function and structural protection, where the thicker edge portions enclose the cavity opening while the thinner center maintains electrical performance
2Power
If the insulating film is made thinner to improve display quality, then the effective voltage is increased, but the cavity exposure limits how thin the film can be made
Solution Approach 1:
The overhang structure is formed in advance before insulating film deposition, creating a protective enclosure that allows the insulating film to be thinned without exposing the cavity. This enables the film thickness to be reduced to increase effective voltage while the overhang prevents the harmful cavity exposure that would limit further thinning
3Ease of manufacture
If the contact hole opening area is reduced, then the pixel electrode can more easily cover the opening, but the electrical connection area is reduced
Solution Approach 1:
The solution moves from a two-dimensional problem (contact hole opening on the surface) to a three-dimensional solution by creating an overhang structure that extends vertically. The pixel electrode protrudes over the contact hole opening, enclosing it from the sides and top, thereby making the opening easy to cover while maintaining adequate electrical connection area at the base of the contact hole
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 enables a thinner insulating film without exposing cavities, improving display quality by maintaining effective voltage and providing a brighter, higher-quality display.
Implementation Method 1
a pixel electrode which covers a part of a surface of the first insulating film, and a base and a side wall of the contact hole, includes a concave portion at a position corresponding to the contact hole... and includes reflectivity
Data Source
AI summary
Disclosed an electro-optic device which includes a reflective pixel electrode which is formed on a base of a contact hole in an approximately rectangular shape or an approximately oval shape, and a side wall thereof, and a second insulating film which covers the reflective pixel electrode, and has a cavity in the contact hole, in which the film thickness of the reflective pixel electrode becomes large toward the upper part from the base of the contact hole.