Wavelength Conversion Member with Oxygen Barrier and Irregularity Layer
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Solution Overview
Problem
Existing wavelength conversion members with quantum dots in liquid crystal display devices experience optical loss and decreased brightness due to high absorbance and total light ray transmittance, despite using high-transmittance base material films.
Innovation Solution
A wavelength conversion member with a base material film having an absorbance of less than 0.9% at 450 nm and total light ray transmittance of less than 92%, incorporating an oxygen barrier layer and an irregularity imparting layer to minimize optical loss and enhance retroreflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a high-transmittance base material film is used to minimize optical loss, then total light ray transmittance increases, but absorbance at 450 nm increases causing brightness decrease
Solution Approach 1:
The patent applies parameter changes by precisely controlling the absorbance parameter of the base material film to be 0.8% or less at 450 nm and the total light ray transmittance to be 85% or more. This quantitative parameter optimization resolves the contradiction by identifying the specific absorbance threshold below which optical loss is minimized while maintaining sufficient brightness.
Solution Approach 2:
The patent employs composite materials by combining the base material film with an oxygen barrier layer and an irregularity imparting layer. This multi-layer composite structure allows each layer to fulfill its specific function: the base material film provides high transmittance, the oxygen barrier layer prevents quantum dot degradation, and the irregularity layer enhances light extraction, collectively resolving the optical loss and brightness contradiction.
2Adaptability or versatility
If quantum dot concentration is increased to improve color reproduction, then color reproduction range increases, but optical loss increases and brightness decreases
Solution Approach 1:
The patent applies the copying principle by using the irregularity imparting layer to create surface micro-structures that replicate and enhance light extraction efficiency. This layer acts as an optical copy that multiplies the effective light output without requiring additional quantum dot concentration, thereby maintaining color reproduction while reducing optical loss.
Solution Approach 2:
The patent optimizes the quantum dot concentration parameter to the minimum effective level while compensating through the irregularity imparting layer. By changing the optical parameters of the film structure rather than increasing material concentration, the patent achieves both good color reproduction and minimal optical loss.
3Strength
If base material film thickness is increased to improve mechanical strength, then film strength increases, but optical loss increases and brightness decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the base material film thickness parameter to the minimum necessary for mechanical strength while maintaining the absorbance below 0.8% and transmittance above 85%. This quantitative optimization allows the film to be as thin as possible while still providing sufficient mechanical support, thereby maximizing brightness.
Solution Approach 2:
The patent uses composite materials where the oxygen barrier layer and irregularity imparting layer compensate for the reduced thickness of the base material film. This multi-layer structure provides the necessary mechanical strength even when the base material film is made extremely thin, thus maintaining brightness while ensuring structural integrity.
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 configuration results in a high-brightness backlight unit with reduced optical loss, maintaining display color and brightness while minimizing the quantum dot concentration and thickness of the wavelength conversion layer.
Implementation Method 1
a wavelength conversion layer containing a quantum dot which emits fluorescent light by exciting light irradiation
Implementation Method 2
an oxygen barrier film is laminated on a layer containing a quantum dot in order to protect the quantum dot from oxygen or the like
Implementation Method 3
an irregularity imparting layer which imparts an irregular structure to a surface of the base material film on a side opposite to the wavelength conversion layer side
Data Source
AI summary
A wavelength conversion member including a wavelength conversion layer containing quantum dots which are excited by exciting light and emit fluorescent light rays, in which the wavelength conversion layer includes base material films on at least one surface, and in the base material films, an absorbance of light at a wavelength of 450 nm measured by using an integrating sphere is less than 0.9%, and a total light ray transmittance is less than 92%.