Low-Reflectance Light-Shielding Layers for Electro-Optical Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electro-optical devices face issues with light leakage due to return light being reflected by metal wiring in the peripheral area, leading to potential malfunction of pixel transistors and image quality degradation, and the previous solutions for light-shielding layers are prone to cracking under stress.
Innovation Solution
A transmissive-type electro-optical device is designed with a first light-shielding layer between the substrate and pixel electrodes, a second light-shielding layer between the substrate and metal wiring, and a third light-shielding layer overlapping with the second light-shielding interlayer area, all with surfaces having lower reflectance than the metal wiring, to prevent return light from being reflected and emitted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light-shielding layer is formed to fill spaces between metal wiring and substrate, then light leakage is prevented, but cracks occur readily in the light-shielding layer due to stress
Solution Approach 1:
The light-shielding layer is divided into multiple separate light-shielding portions arranged in a matrix pattern, with each portion having light-shielding openings between them. This segmentation reduces stress concentration that would otherwise cause cracks while maintaining effective light shielding through the distributed arrangement of multiple portions
Solution Approach 2:
The light-shielding layer is designed with varying local properties: the light-shielding portions provide high light shielding where needed, while the light-shielding openings provide stress relief zones. This local differentiation allows the structure to simultaneously achieve light leakage prevention and crack resistance
2Ease of operation
If metal wiring is provided in the peripheral area, then electrical connectivity is achieved, but return light is reflected by the metal wiring causing light leakage and potential transistor malfunction
Solution Approach 1:
The light-shielding layer is positioned between the metal wiring and the substrate to act as an intermediary that blocks reflected light from reaching the semiconductor layer. This intermediate structure prevents the harmful interaction between metal wiring reflections and the transistor while maintaining the electrical connectivity function of the metal wiring
3Object-affected harmful factors
If a continuous light-shielding layer is formed, then light leakage is effectively blocked, but stress concentration causes cracks in the light-shielding layer
Solution Approach 1:
The continuous light-shielding layer is segmented into multiple discrete light-shielding portions arranged in a matrix, with light-shielding openings between them. This segmentation distributes stress across multiple smaller units rather than concentrating it in a single continuous layer, preventing crack formation while maintaining collective light shielding effectiveness
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
The solution effectively blocks return light from reaching the semiconductor layer, preventing pixel transistor malfunction and reducing light leakage, while the divided light-shielding layers minimize cracking due to stress concentration.
Implementation Method 1
a light-absorptive light-shielding layer (the low-reflection layer) is provided to the metal wiring, to prevent, when light-source light is incident on a peripheral area that surrounds a pixel area
Implementation Method 2
The electro-optical device modulates a light-source light by means of the electro-optical layer for each of the pixels
Implementation Method 3
the modulated light may occasionally be reflected by the optical system, the wire-grid polarizing element, and the like that are disposed at the emission side
Data Source
AI summary
An element substrate of an electro-optical device includes, in a peripheral area surrounding a pixel area, a metal wiring provided at one surface side of a first substrate that is a substrate body, and a plurality of second light-shielding layers overlapping with the metal wiring between the first substrate and the metal wiring. A second light-shielding interlayer area overlapping with the metal wiring is present between the plurality of second light-shielding layers. A third light-shielding layer is formed in a manner overlapping in a plan view with the second light-shielding interlayer area between the first substrate and the metal wiring. Surfaces of the second light-shielding layer and the third light-shielding layer at the first substrate side have lower reflectance than a surface of the metal wiring at the first substrate side.