Anti-Reflective Layer Design for Transparent OLED Displays
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Solution Overview
Problem
Organic light emitting display devices face issues with external light reflection, which degrade visibility and contrast, especially in transparent displays where polarizing plates are often omitted to enhance light transmittance, leading to reduced luminance and contrast ratios.
Innovation Solution
An anti-reflective layer with a double-layer structure, comprising an intermediate layer and a semi-transparent layer, is applied to the conductive lines in the display device to reduce external light reflection through destructive interference, eliminating the need for polarizing plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a polarizing plate is used to prevent external light reflection, then visibility and contrast are improved, but luminance is reduced by 50% or more
Solution Approach 1:
The patent converts the harmful reflection of external light into a beneficial effect by using a specific refractive index matching relationship. The encapsulant resin is designed with a refractive index that matches the average of the semiconductor layer and organic light-emitting layer, causing reflected light to be redirected toward the viewing angle rather than creating glare, thus improving visibility without sacrificing luminance
Solution Approach 2:
The patent changes the refractive index parameter of the encapsulant resin to specifically match the average refractive index of the semiconductor and organic light-emitting layers. This parameter optimization enables the anti-reflection function while maintaining high luminance output, resolving the contradiction between reducing reflection and preserving brightness
2Illumination intensity
If driving power is increased to compensate for reduced luminance from a polarizing plate, then luminance is maintained, but the lifespan of the organic light emitting layer is reduced
Solution Approach 1:
The patent eliminates the need for high driving power by using refractive index matching to control light reflection. This converts the harmful reflection into a beneficial directional light distribution, maintaining luminance at normal driving power levels and thereby preserving the lifespan of the organic light-emitting layer
3Illumination intensity
If a transparent area is arranged to transmit light from rear background, then light transmittance is improved, but external visibility and contrast ratio are degraded
Solution Approach 1:
The patent applies different optical properties to different regions: the transparent area allows background light transmission while the encapsulant resin with matched refractive index controls reflection locally. This local optimization enables the transparent area to maintain both high transmittance and good external visibility through controlled light distribution at specific viewing angles
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 anti-reflective layer effectively improves visibility and contrast ratios by minimizing external light reflection, maintaining luminance while eliminating the need for costly polarizing plates, particularly in transparent organic light emitting display devices.
Implementation Method 1
an anti-reflective layer arranged on the conductive line, wherein the anti-reflective layer includes an intermediate layer arranged on the conductive line and a semi-transparent layer arranged on the intermediate layer
Data Source
AI summary
An organic light emitting display device comprises a substrate that includes a plurality of pixel regions; a conductive line arranged on the substrate; and an anti-reflective layer arranged on the conductive line, wherein the anti-reflective layer includes an intermediate layer arranged on the conductive line and a semi-transparent layer arranged on the intermediate layer, and the conductive line is electrically connected with the semi-transparent layer.