Backlight Unit Scattering Particles for White Light Efficiency
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Solution Overview
Problem
Conventional backlight units using quantum dot phosphors require a large amount of phosphors to generate white light, increasing production costs and unit costs, and existing scattering particles interfere with secondary light extraction when used in excess.
Innovation Solution
A quantum dot composite comprising quantum dot phosphors and scattering particles, where the scattering particles include first and second particles of different sizes (5-50 nm) to scatter primary light efficiently without interfering with secondary light, allowing for a reduced amount of quantum dot phosphors and improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large amount of quantum dot phosphors is used to generate white light, then the efficiency of white light generation is improved, but the production cost and unit cost increase
Solution Approach 1:
The patent changes the physical and chemical parameters of the scattering particles by using a core-shell structure with specific materials (TiO2 core, SiO2 shell) and controlled size distribution (5-50 nm). This parameter optimization enables efficient light scattering with minimal quantum dot phosphor content, resolving the contradiction between generation efficiency and material quantity.
Solution Approach 2:
The patent employs composite scattering particles consisting of a TiO2 core and SiO2 shell, combining the high refractive index of TiO2 for effective scattering with the protective and optical properties of SiO2. This composite structure achieves superior light scattering performance that allows reduced quantum dot phosphor usage while maintaining high white light generation efficiency.
2Productivity
If conventional scattering particles are used to scatter primary light, then the efficiency of quantum dot phosphors is improved to some degree, but when the content exceeds a predetermined level, the scattering particles interfere with the extraction of secondary light, ending up lowering the efficiency
Solution Approach 1:
The patent applies local quality by creating scattering particles with non-uniform structure (core-shell) and specific size distribution (5-50 nm range). The TiO2 core provides strong scattering for primary light, while the SiO2 shell modifies the optical properties to reduce interference with secondary light extraction. This localized structural differentiation resolves the contradiction between improving phosphor efficiency and preventing harmful interference.
Solution Approach 2:
The patent optimizes critical parameters including particle size (5-50 nm), core-shell structure, and material composition (TiO2/SiO2). These parameter changes enable the scattering particles to effectively scatter primary light while being transparent or less interfering with the longer wavelength secondary light from quantum dots, thus improving efficiency without creating harmful effects.
3Productivity
If the size of scattering particles is increased to improve primary light scattering, then the efficiency of quantum dot phosphors is improved, but the scattering particles may interfere with the extraction of secondary light
Solution Approach 1:
The patent segments the scattering particle into two distinct parts: a TiO2 core for primary light scattering and a SiO2 shell for optical optimization. This segmentation allows each component to perform its specific function - the core provides scattering power while the shell reduces interference with secondary light, resolving the size-related contradiction.
Solution Approach 2:
By combining TiO2 and SiO2 in a core-shell composite structure, the patent achieves optimal balance between scattering efficiency and secondary light extraction. The TiO2 core (high refractive index) scatters primary light effectively, while the SiO2 shell (lower refractive index, transparent in visible range) reduces interference with secondary light, solving the contradiction that arises from using larger single-material particles.
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 solution enables the generation of white light with a smaller number of quantum dot phosphors, reducing production costs and unit costs while maintaining high efficiency and optical uniformity, making the backlight unit slimmer and more cost-effective.
Implementation Method 1
the primary light should be fully scattered. When the primary light is scattered, a path length of the primary light may increase
Implementation Method 2
The quantum dots have a property of emitting different wavelengths of light depending on a type of material and a size of a particle
Implementation Method 3
The quantum dot phosphors are excited by primary light supplied from light sources to emit secondary light which has a different wavelength from the primary light
Data Source
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AI summary
A backlight unit including a plurality of light sources configured to emit primary light, and a quantum dot composite. The quantum dot composite includes quantum dot phosphors excited by primary light supplied from the plurality of light sources so as to emit secondary light having a different wavelength than the primary light, and scattering particles that are configured to scatter the primary light. The scattering particles include first scattering particles, and second scattering particles different from the first scattering particles in size and composed of particles each having a diameter in the range of 5 to 50 nm.