Light Down Conversion Film Asymmetric Micro-Prisms
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Solution Overview
Problem
Current quantum-dot backlight systems face high costs due to the need for large quantities of expensive quantum-dot materials, which limits their efficiency and color purity, and suffer from additional light loss from secondary absorption when incorporating light scattering features to enhance optical path and light extraction.
Innovation Solution
A light down-conversion film with a quantum-dot layer and an input substrate featuring refractive asymmetric micro-prisms on its surfaces, which refract and extend the optical path of incident blue light, allowing for higher down-conversion efficiency without the need for additional scattering particles, thereby reducing the required quantum-dot density and material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light scattering particles are added to quantum-dot film to increase optical path and improve light extraction, then light extraction efficiency is improved, but secondary absorption increases causing additional light loss
Solution Approach 1:
The patent divides the light management function into two separate components: the quantum-dot layer handles down-conversion while the input substrate with micro-prisms handles light extraction. This segmentation allows each component to optimize its function without the trade-off present in diffusive films where scattering particles cause both extraction improvement and secondary absorption.
Solution Approach 2:
The input substrate with asymmetric micro-prisms acts as an intermediary between the light guide plate and the quantum-dot layer. It pre-conditions the incident blue light by extending its optical path through refraction before the light enters the quantum-dot layer, thereby improving extraction efficiency without requiring scattering particles within the quantum-dot film itself that would cause secondary absorption.
2Productivity
If high particle density of quantum dots is used to increase down-conversion possibility, then down-conversion efficiency is improved, but material cost increases significantly
Solution Approach 1:
The asymmetric micro-prisms on the input substrate perform preliminary action by extending the optical path of incident blue light before it enters the quantum-dot layer. This pre-conditioning increases the probability of down-conversion events, allowing the system to achieve high down-conversion efficiency with lower quantum-dot particle density, thereby reducing material costs.
Solution Approach 2:
The patent changes the optical parameters of the incident light by using asymmetric micro-prisms to extend the optical path length. This parameter change (increased path length) compensates for the reduced quantum-dot density, maintaining high down-conversion efficiency while using less expensive quantum-dot material.
3Use of energy by moving object
If diffusive quantum-dot film structure is used to scatter incident light and increase optical path, then light utilization is improved, but device complexity and cost increase due to additional scattering particles and surface features
Solution Approach 1:
The patent extracts the light scattering function from the quantum-dot film itself and places it in a separate input substrate with asymmetric micro-prisms. This extraction simplifies the quantum-dot film structure, eliminating the need for scattering particles within it, while still achieving extended optical path and improved light utilization through the micro-prism array.
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 film achieves improved optical efficiency and color purity by extending the optical path of incident light within the quantum-dot layer, increasing the likelihood of down-conversion while minimizing secondary absorption, thus reducing the need for expensive quantum-dot materials and enhancing the cost-performance of quantum-dot lighting methods.
Implementation Method 1
The first steep segments and the first shallow segments adjacent to each other form a first rounded tip and a first rounded valley for refraction of the first light and the second light. The second steep segments and the second shallow segments adjacent to each other form a second rounded tip and a second rounded valley for refraction of the first light and the second light.
Implementation Method 2
The quantum dots are adapted to absorb a part of the first light with first wavelength which exits by the light guide plate and the input substrate in sequence before down-convert into second light with second wavelength and reemit.
Data Source
AI summary
The disclosure provides a display backlight unit and its light down conversion film. The light down conversion film may include a quantum-dot layer sandwiched between input substrate and an exit substrate. First and second refractive asymmetric micro-prisms are disposed on two opposite input and first exit surfaces of the input substrate, respectively. On the input surface of the input substrate, multiple arrays of the asymmetric refractive asymmetric micro-prisms preserve the large off-axis angle of incident light with first wavelength. On the first exit surface of the input substrate, multiple arrays of the refractive asymmetric micro-prisms increase the reflectance of the large incident angle light. A second exit surface of the exit substrate includes refractive symmetric micro-prisms. The refractive asymmetric micro-prisms of the input substrate and the refractive asymmetric micro-prisms of the exit substrate have rounded tips and valleys for enhancing refraction of the first light and the second light.