OLED External Light Blocking Member for High Contrast
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Solution Overview
Problem
Organic light emitting diode (OLED) displays face challenges in achieving high contrast ratios without using thick circular polarizer films, which increases device thickness and production costs, and limits flexibility.
Innovation Solution
The implementation of an external light blocking member with a lower and upper portion, where the lower portion is recessed in pixels and made of materials like metals, metal oxides, or dielectric layers, and the upper portion is uniformly thin, preventing external light reflection and enhancing contrast without the need for a circular polarizer film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a circular polarizer film is used to increase contrast ratio, then the contrast ratio is improved, but the device thickness increases and production costs increase
Solution Approach 1:
The patent extracts and eliminates the circular polarizer film from the display structure, replacing it with an external light blocking member that achieves the same contrast enhancement function without the thickness penalty of 200 μm polarizer film
Solution Approach 2:
The patent changes the optical parameters by using a thin external light blocking member with specific thickness characteristics (first portion thinner than second portion) to achieve contrast enhancement without the thickness of traditional polarizer films
2Illumination intensity
If a circular polarizer film is used to increase contrast ratio, then the contrast ratio is improved, but production costs increase
Solution Approach 1:
The patent removes the expensive circular polarizer film from the display structure and replaces it with a more cost-effective external light blocking member that can be manufactured using standard thin-film deposition techniques
Solution Approach 2:
The patent employs a cost-effective external light blocking member structure that can be manufactured using inexpensive materials and standard fabrication processes, eliminating the need for expensive polarizer films
3Illumination intensity
If a circular polarizer film is used to increase contrast ratio, then the contrast ratio is improved, but the device flexibility is reduced
Solution Approach 1:
The patent extracts the rigid circular polarizer film from the display structure and replaces it with a flexible external light blocking member that maintains contrast enhancement while enabling device flexibility and potential bending applications
Solution Approach 2:
The patent employs thin-film external light blocking members that can be made flexible, allowing the display device to be bent or conform to different surfaces while maintaining the contrast enhancement function
4Illumination intensity
If external light is blocked to improve contrast, then contrast ratio is improved, but light emission in pixel areas may be affected
Solution Approach 1:
The patent applies different thickness characteristics of the external light blocking member at different locations: the first portion in pixel areas has optimized thickness to block external light while allowing emitted light to pass, and the second portion in non-pixel areas has greater thickness for maximum light blocking
Solution Approach 2:
The external light blocking member is segmented into different portions with different thickness characteristics - the first portion for pixel areas and the second portion for non-pixel areas - allowing optimized performance in each region
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 solution increases the contrast ratio of OLED displays, reduces their thickness, and enhances flexibility by blocking external light effectively without using a thick polarizing plate, resulting in a slimmer and more flexible device.
Implementation Method 1
Each organic light emitting element emits light by energy generated when an exciton generated by combining an electron and a hole in the organic emission layer falls from an exited state to a ground state
Implementation Method 2
The upper external light blocking member may include at least one of a metal layer, a metal oxide layer, a metal nitride layer, a dielectric layer, and a black layer
Implementation Method 3
preventing external light reflection and enhancing contrast
Data Source
AI summary
An organic light emitting diode (OLED) display includes: a substrate including a plurality of pixels, a thin film transistor disposed in the pixels; an organic light emitting element connected to the thin film transistor and disposed in the pixels, an encapsulation member located on the organic light emitting element, and an external light blocking member disposed above or under the encapsulation member and including a first portion and a second portion. The first portion has a thickness that is thinner than a thickness of the second portion, and the first portion is disposed in the pixels.