Electro-Optical Device Reflection Layer Resonance Control
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Solution Overview
Problem
The existing organic electroluminescence (EL) devices with resonant structures suffer from reduced color purity due to surface roughness of the reflection film, leading to lower brightness and non-uniform optical path lengths, which affects the display quality.
Innovation Solution
The electro-optical device incorporates a reflection layer with high and low reflectance portions, where the high reflectance portion is inside the opening and the low reflectance portion is outside, using underlayer films made of titanium and reflection films made of aluminum or its alloys, to maintain high reflectance and prevent surface roughness, ensuring light is amplified at specific wavelengths and reducing color impurity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the reflection film is made of aluminum or aluminum-containing alloy, then high reflectance is achieved, but surface roughness increases due to heat and stress during insulating layer formation, causing diffuse reflection and reduced display light brightness
Solution Approach 1:
The invention uses a composite structure consisting of a reflection film made of aluminum or aluminum-containing alloy combined with an insulating layer. The key is optimizing the formation conditions and material selection to maintain the high reflectance of the aluminum-based reflection film while minimizing surface roughness degradation during insulating layer formation through controlled heat and stress management.
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 enhances the image quality by maintaining high reflectance inside the opening, suppressing light reflection from the peripheral edge, and preventing color impurity, resulting in improved brightness and uniformity of the display.
Implementation Method 1
The reflection layer is disposed across the plurality of pixels, and has a high reflectance portion and a low reflectance portion whose reflectance is lower than that of the high reflectance portion
Implementation Method 2
Light emitted by the light-emitting functional layer is repeatedly reflected between the reflection film and the opposing electrode, so that the light is ejected as display light in which the light intensity at a resonant wavelength matching the optical path length between the reflection film and the opposing electrode is amplified
Data Source
AI summary
Provided is a display apparatus in which a plurality of pixels are arranged. The pixels have a reflection layer, an optical distance adjusting layer, a pixel electrode, an insulating film, a light-emitting functional layer, and an opposing electrode that are sequentially layered in a Z direction. The insulating film has an opening that overlaps part of the pixel electrode. The reflection layer is disposed across the plurality of pixels, and has a high reflectance portion (where a first underlayer film and a reflection film are layered) and a low reflectance portion (where a second underlayer film and the reflection film are layered). The high reflectance portion (where the first underlayer film and the reflection film are layered) is disposed so as to overlap at least part of the opening when viewed from above.