Quantum Dot Display Opening Geometry for Light Conversion Efficiency
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Solution Overview
Problem
Conventional display apparatuses with color conversion units suffer from low light efficiency, which hinders the display of high-quality images.
Innovation Solution
The display apparatus incorporates specific geometric relationships between pixel openings, bank openings, and filter openings, with defined distances and ratios, along with a quantum dot layer and color filter layer, to enhance light conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a color conversion unit is used to convert light of a first color into light of a second color, then full-color display capability is achieved, but light efficiency deteriorates
Solution Approach 1:
The patent optimizes the thickness of the quantum dot layer and the distances between layers (specifically setting the ratio of the second distance to the first distance between 0.625 and 1) to improve light extraction efficiency. By changing these physical parameters, the system achieves better light efficiency while maintaining color conversion functionality.
Solution Approach 2:
The patent introduces a vertical dimension by creating a cavity structure beneath the quantum dot layer and optimizing the distance relationships between layers. This three-dimensional structural optimization allows for improved light extraction in the vertical direction, compensating for the light efficiency loss from color conversion.
2Length of stationary object
If the quantum dot layer is placed close to the emission layer for compact structure, then device thickness is reduced, but light extraction efficiency deteriorates
Solution Approach 1:
The patent creates a vertical cavity structure beneath the quantum dot layer and optimizes the distance between the opposite electrode and the quantum dot layer (first distance). This vertical dimension optimization allows light to be extracted more efficiently through the cavity, compensating for the reduced horizontal spacing.
Solution Approach 2:
The patent specifically optimizes the ratio of the second distance (from filter opening edge to pixel opening edge) to the first distance (from opposite electrode to quantum dot layer) to be between 0.625 and 1. This parameter optimization ensures that even with reduced overall thickness, the light extraction efficiency is maintained or improved.
3Illumination intensity
If the pixel opening area is increased to improve light emission, then brightness is improved, but color purity deteriorates due to increased overlap with bank and filter openings
Solution Approach 1:
The patent optimizes the ratio of the second distance to the first distance to be between 0.625 and 1, which controls the relative positioning and sizing of the openings. This parameter optimization allows the pixel opening to be sufficiently large for brightness while maintaining appropriate spacing to preserve color purity.
Solution Approach 2:
The patent makes the bank opening and filter opening areas greater than the pixel opening area, which provides sufficient margin for light extraction while the optimized distance ratios prevent excessive overlap that would compromise color purity. This partial excess in opening size compensates for light loss without sacrificing precision.
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 improves light efficiency, enabling the display of high-quality images by optimizing the interaction between pixel, bank, and filter structures.
Implementation Method 1
a quantum dot layer or a light-transmitting layer disposed in the bank opening defined by the bank
Implementation Method 2
an emission layer disposed over the pixel electrode, where the emission layer emits light having a wavelength in a first wavelength band
Implementation Method 3
a color filter layer which fills the filter opening and allows the light having the wavelength in the second wavelength band to pass therethrough
Data Source
AI summary
A display apparatus includes a pixel-defining layer defining a pixel opening exposing a central portion of a pixel electrode; an opposite electrode disposed over the pixel-defining layer; a bank over the opposite electrode and defining a bank opening overlapping the pixel opening; and a filter-defining layer disposed over the bank and defining a filter opening overlapping the pixel opening. A distance between an upper surface of a portion of the opposite electrode overlapping the pixel opening and a lower surface of the quantum dot layer or the light-transmitting layer is defined as a first distance, a distance between an edge of the filter opening and an edge of the pixel opening in the plan view is defined as a second distance, and a ratio of the second distance to the first distance is greater than or equal to 0.625 and less than or equal to 1.