Quantum Dot Display Optical Switching for Deep Black Color
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Solution Overview
Problem
Display devices using quantum dots face challenges in achieving deep black colors due to photoluminescence from external light incidence.
Innovation Solution
A display device design incorporating a first and second electrode with a light-emitting layer containing quantum dots, a third electrode capable of forming an electrical field, and an optical adjustment element that changes transmittance based on the potential difference between the second and third electrodes, suppressing external light incidence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If quantum dots are used in the light-emitting layer, then the display device can achieve high color purity and brightness, but external light incident from the viewing surface causes photoluminescence that prevents deep black color display
Solution Approach 1:
The patent introduces an optical adjustment element as an intermediary component positioned between the light-emitting layer and the viewing surface. This element acts as a mediator that selectively blocks external light from reaching the quantum dots while allowing emitted light to pass through, thereby eliminating photoluminescence without compromising display brightness
Solution Approach 2:
The patent segments the display structure into distinct functional layers: a light-emitting layer containing quantum dots and a separate optical adjustment element layer. This segmentation allows independent optimization of each layer's function - the quantum dots provide high-color-purity emission while the optical adjustment element suppresses photoluminescence, resolving the contradiction between brightness and black color purity
2Object-affected harmful factors
If an optical adjustment element is added to suppress photoluminescence, then deep black color can be displayed, but the device structure becomes more complex
Solution Approach 1:
The optical adjustment element is designed with multi-functionality: it serves as both an optical component for suppressing photoluminescence and as an electrode (third electrode) that can form an electrical field. This dual functionality allows the element to suppress photoluminescence while integrating into the existing device architecture, minimizing structural complexity
Solution Approach 2:
The patent merges the optical adjustment element with the third electrode function, combining optical suppression capability with electrical field formation in a single integrated component. This merging reduces the total number of separate components needed, thereby limiting the increase in device complexity while achieving photoluminescence suppression
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
Enables high-contrast displays with deep black colors by blocking photoluminescence from external light, maintaining high-purity black color purity.
Implementation Method 1
an optical adjustment element overlapping the light-emitting layer in a plan view and having light transmittance that changes in accordance with a potential difference between the second electrode and the third electrode
Implementation Method 2
a light-emitting layer containing quantum dots and overlapping the first electrode and the second electrode
Implementation Method 3
a third electrode capable of forming an electrical field between the second electrode and the third electrode
Data Source
AI summary
This display device includes a first electrode and a second electrode overlapping each other in a plan view, a light-emitting layer containing quantum dots and overlapping the first electrode and the second electrode in a plan view, a third electrode capable of forming an electrical field between the second electrode and third electrode, and an optical adjustment element overlapping the light-emitting layer in a plan view and having light transmittance that changes in accordance with a potential difference between the second electrode and the third electrode.