Elliptic Arc Microlens for OLED Light Extraction
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Solution Overview
Problem
Conventional organic electroluminescence (EL) display devices experience decreased light-extraction efficiency due to the shape of the microlenses, which have a greater distance between the lens center and the luminescent region's center in the long axis direction, leading to increased light reflection and reduced extraction efficiency.
Innovation Solution
A display panel device with a lens structure where the height between the luminescent face and the lens apex is uniform along a straight line in the long axis direction, and both end parts of the lens have cross-sections with elliptic arcs, enhancing light transmission and reducing reflection across both the short and long axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional microlenses with greater distance between lens center and luminescent region center in long axis direction are used, then light transmission is achieved, but light reflection increases and extraction efficiency decreases
Solution Approach 1:
The patent applies asymmetry by making the lens cross-sectional shape different in the long axis direction compared to the short axis direction. Specifically, the cross-section along the long axis direction has a first shape while the cross-section along the short axis direction has a second shape, optimizing light extraction in each direction independently to reduce reflection and improve overall extraction efficiency
Solution Approach 2:
The patent changes geometric parameters of the lens by defining specific cross-sectional shapes along different axes. The first cross-sectional shape along the long axis and the second cross-sectional shape along the short axis represent parameter optimization to minimize light reflection and maximize extraction efficiency
2Loss of energy
If uniform height between luminescent face and lens apex along long axis direction is implemented, then light extraction efficiency improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by specifying that the height between the luminescent face and lens apex is uniform along the long axis direction (first direction) while allowing different characteristics along the short axis direction. This localized uniformity optimization improves light extraction efficiency in the critical long axis direction without requiring complete uniformity in all directions
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 significantly improves light-extraction efficiency by ensuring uniform light emission and minimizing reflection, resulting in a 41% increase in light extraction compared to conventional designs.
Implementation Method 1
the lens deflects the light emitted from the luminescent layer in both of the short axis direction and the long axis direction of luminescent region
Implementation Method 2
Conventional organic electroluminescence (EL) display devices experience decreased light-extraction efficiency due to the shape of the microlenses, which have a greater distance between the lens center and the luminescent region's center in the long axis direction, leading to increased light reflection
Data Source
AI summary
Provided is a display panel device including a pixel unit including a luminescent layer, and a lens that covers a luminescent region of the luminescent layer placed above the pixel unit and that transmits light emitted from the luminescent layer. The height between a luminescent face of the luminescent region and an apex of the lens is uniform along the straight line in the long axis direction of the luminescent region. Furthermore, at both end parts of the lens, a cross-section of the light emitting side corresponding to the long axis direction of the luminescent region has a shape of an elliptic arc having a predetermined curvature.