Segmented Light Blocking Layer for OLED Display Reflection Control
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Solution Overview
Problem
Organic electroluminescence display devices face issues with mirror surfaces due to light-reflective electrodes, leading to reduced light extraction efficiency and colored reflections from color filters when external light is reflected.
Innovation Solution
A display device structure with a light-blocking layer having openings above color filters to enhance light extraction efficiency, while minimizing colored reflections by increasing the spatial frequency of openings and using a transparent common pixel electrode to allow light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a light-reflective electrode is used in the display device, then the electrode can effectively reflect light, but mirror surfaces and colored reflections occur reducing light extraction efficiency
Solution Approach 1:
The light-blocking layer is divided into multiple openings arranged in a specific pattern, segmenting the light path to reduce mirror surfaces and colored reflections while maintaining light extraction efficiency
Solution Approach 2:
A light-blocking layer with openings is introduced as an intermediary structure between the light-emitting region and the external environment, mediating light extraction while preventing harmful reflections
2Shape
If a black matrix is used to demarcate pixels, then pixel boundaries are clearly defined, but moire patterns appear due to intermittent black areas
Solution Approach 1:
The light-blocking layer is segmented into multiple small openings rather than continuous black matrix lines, which maintains pixel demarcation while reducing moire patterns by eliminating large intermittent black areas
Solution Approach 2:
The light-blocking structures are arranged in a three-dimensional configuration with specific spatial frequencies, adding a dimensional aspect to pixel demarcation that reduces moire visibility
3Use of energy by moving object
If the light-blocking layer has large openings, then light extraction efficiency is high, but colored reflections become more visible
Solution Approach 1:
The openings in the light-blocking layer are designed with asymmetric dimensions where the length in the first direction is greater than the length in the second direction, optimizing the balance between light extraction and reflection control
Solution Approach 2:
The spatial frequency and dimensions of the openings are carefully controlled within specific ranges to optimize the trade-off between light extraction efficiency and reduction of colored reflections
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 structure effectively reduces the visibility of reflection rainbows and maintains high light extraction efficiency by minimizing colored reflections and maintaining image quality across viewing angles.
Implementation Method 1
a light blocking layer having a plurality of openings; The light blocking layer blocks light from regions other than the light emitting region and allows light from the light emitting region to be output
Implementation Method 2
the other electrode is provided over a plurality of pixels as a common pixel electrode... a transparent common pixel electrode to allow light transmission
Data Source
AI summary
A display device includes a plurality of pixels each including a light emitting region; and a light blocking layer provided on a side of the plurality of pixels on which light is output. In each of the plurality pixels, the light blocking layer has a plurality of openings allowing light from the light emitting region to be output. In one embodiment, in the light blocking layer, the openings adjacent to each other may be located line-symmetrically. In one embodiment, in the light blocking layer, the openings adjacent to each other may be located point-symmetrically.