Reflective Electrode Display with Segmented Polarizer
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Solution Overview
Problem
Display devices with light-emitting elements, such as QLEDs and OLEDs, face challenges in reducing visibility of external light reflected by reflective electrodes and achieving perfect black due to the absorption of light by polarizing plates used to mitigate reflection.
Innovation Solution
A display device design featuring a light-emitting element with a reflective first electrode, a transparent second electrode, a light-emitting layer, a polarizing plate positioned in the light emission direction to partially overlap with subpixels, and a light-blocking layer raised higher than the polarizing plate to minimize light absorption and reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If polarizing plates are provided to the entire surface of the display region to reduce reflection of external light, then visibility of external light reflected on reflective electrode is reduced, but light intensity from light-emitting elements decreases because approximately half of the light is absorbed into the polarizing plates
Solution Approach 1:
The display region is divided into two distinct areas: a first display region with polarizing plates to block reflected external light, and a second display region without polarizing plates to preserve light intensity from light-emitting elements. This segmentation allows each region to serve its specific function optimally.
Solution Approach 2:
Different regions of the display are assigned different properties: the first display region has polarizing plates for anti-reflection functionality, while the second display region lacks polarizing plates to maintain high light transmission. This local differentiation resolves the contradiction by applying the polarizing plate feature only where needed.
2Object-affected harmful factors
If polarizing plates are provided to the entire surface to reduce external light reflection, then reflection visibility is reduced, but perfect black cannot be achieved when light-emitting elements do not emit light
Solution Approach 1:
The display region is segmented into areas with and without polarizing plates. The second display region without polarizing plates allows for perfect black when light-emitting elements are off, as there is no light absorption, while the first display region with polarizing plates handles external light reflection.
Solution Approach 2:
The second display region is designed without polarizing plates to achieve perfect black levels, while the first display region incorporates polarizing plates for anti-reflection. This local quality differentiation allows the display to achieve both reduced reflection visibility and perfect black performance.
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 reduces the visibility of external light reflected on the reflective electrode and enhances the release of light from the light-emitting elements, improving image clarity and achieving better black levels.
Implementation Method 1
a first electrode that reflects visible light
Implementation Method 2
a polarizing plate provided on the light-emitting element disposed in a light emission direction
Implementation Method 3
approximately half of the light emitted from the light-emitting elements is absorbed into the polarizing plates
Implementation Method 4
a light-emitting layer provided between the first electrode and the second electrode
Data Source
AI summary
A display device includes: a light-emitting element provided on a substrate, and including a first electrode that reflects visible light, a second electrode that transmits visible light, and a light-emitting layer provided between the first electrode and the second electrode; a subpixel that is a light-emitting region in plan view of the light-emitting element; a polarizing plate provided on the light-emitting element disposed in a light emission direction in which light is emitted from the light-emitting element, the polarizing plate partially overlapping with the subpixel in plan view; and a light-blocking layer provided at least partially around the subpixel and raised higher in the light emission direction than the polarizing plate.