Electro-optical Device Vacuum Cavity Reflection Efficiency
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Solution Overview
Problem
Existing electro-optical devices have low light reflection efficiency due to a small difference in refractive index at the boundary surface, which limits light utilization efficiency.
Innovation Solution
An electro-optical device with a cavity formed between a wall portion and a transmissive body, where the cavity has a significant refractive index difference from the transmissive body, enhancing reflection efficiency by using a vacuum for easier cavity formation and ensuring the wall portion and transmissive body have a refractive index difference for improved light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a boundary surface between two insulating films with different refractive indices is used as a reflection surface, then light can be reflected toward the opening regions, but the reflection efficiency is low due to the small difference in refractive index
Solution Approach 1:
The patent changes the refractive index parameter by introducing a cavity (vacuum or air gap) between the wall portion and transmissive body. The cavity has a refractive index of approximately 1.0, which creates a large refractive index difference with the transmissive body (refractive index 1.5-2.0), thereby significantly improving reflection efficiency compared to using two insulating films with similar refractive indices.
Solution Approach 2:
The cavity acts as an intermediary layer between the wall portion and transmissive body. This intermediary structure enables high reflection efficiency by creating a sharp refractive index boundary, while also providing electrical insulation and preventing optical leakage currents between adjacent pixel electrodes.
2Reliability
If a cavity is formed between the wall portion and transmissive body to increase refractive index difference, then reflection efficiency improves, but device complexity increases
Solution Approach 1:
The patent segments the structure by introducing a distinct cavity layer between the wall portion and transmissive body. This segmentation creates a clear interface with high refractive index difference, improving reflection efficiency. The cavity is formed as a separate structural element that can be independently controlled during manufacturing.
Solution Approach 2:
The cavity structure replicates the concept of total internal reflection used in optical waveguides and fiber optics. By creating a similar refractive index boundary condition, the patent achieves high reflection efficiency without requiring complex multi-layer coating systems or metallic reflective layers.
3Area of stationary object
If the wall portion and transmissive body are positioned close to each other, then device area is reduced, but optical leakage currents may occur between adjacent pixel electrodes
Solution Approach 1:
The cavity serves as an intermediary insulating layer that prevents direct contact between the wall portion and transmissive body of adjacent pixel electrodes. This intermediary structure effectively blocks optical leakage currents while maintaining compact device dimensions, as the cavity provides sufficient electrical insulation without requiring large spacing.
Solution Approach 2:
The cavity functions as a thin-film insulating barrier that provides electrical isolation between adjacent pixels. This thin-film approach allows the device to maintain small area while preventing harmful optical leakage currents, as the cavity thickness is sufficient for insulation but does not significantly increase device dimensions.
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 design significantly improves light reflection efficiency, enhancing light utilization and preventing optical leakage currents by ensuring high reflection of obliquely incident light towards the transmissive body, thereby improving display performance.
Implementation Method 1
the boundary surface between the transmissive body and the cavity reflects the light toward the transmissive body with high reflection efficiency
Implementation Method 2
There is a significant difference in refractive index at the boundary surface between the transmissive body and the cavity
Data Source
AI summary
In an electro-optical device, one surface side of a first substrate is provided with a wall portion covering a light-shielding body with an edge overlapping a pixel electrode in a plan view and a transmissive body located in a region surrounded by the wall portion. A cavity is provided between a side surface of the wall portion and the transmissive body. The cavity has a refractive index of 1, and thus, there is a significant difference in refractive index at a boundary surface between the transmissive body and the cavity. Therefore, even in a case where light travels to advance obliquely toward the wall portion, the boundary surface between the transmissive body and the cavity reflects the light toward the transmissive body with high reflection efficiency, and contributes to display. The cavity is a vacuum.