Core-Shell Phosphor Coating for LED Backlight Heat Resistance
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Solution Overview
Problem
Liquid crystal displays using light emitting diodes (LEDs) face phosphor degradation due to heat generated, affecting the reliability and performance of the backlight system.
Innovation Solution
A backlight device incorporating a diffuser sheet with core-shell phosphors coated with a layer of silica, polystyrene, or urethane, positioned away from the light source to prevent degradation and ensure reliability, converting blue light into white light for improved display performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phosphor is positioned close to the light source to improve light conversion efficiency, then light conversion efficiency is improved, but phosphor degradation due to heat increases
Solution Approach 1:
The patent introduces a heat-resistant coating layer as an intermediary substance between the phosphor particles and the LED light source. This coating layer mediates the thermal interaction by protecting the phosphor from direct heat exposure while allowing the phosphor to remain in close proximity to the light source for efficient light conversion. The coating acts as a thermal barrier that enables the phosphor to withstand the high temperature environment near the LED.
Solution Approach 2:
The patent creates a composite structure by coating phosphor particles with heat-resistant materials. The composite material combines the light-conversion properties of phosphor with the thermal stability of the coating material, resulting in a composite phosphor particle that maintains both high light conversion efficiency and resistance to thermal degradation.
2Reliability
If phosphor is coated with protective layer to prevent degradation, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the coating parameters including coating material selection, coating thickness, and coating method to achieve effective protection with minimal process complexity. By carefully selecting the coating material properties and controlling the coating thickness within specific ranges, the patent achieves reliable phosphor protection while maintaining manufacturing feasibility.
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 effectively prevents phosphor degradation, enhancing the reliability and longevity of the backlight system by isolating the core-shell phosphors from heat sources and ensuring consistent light emission, thereby improving the overall display quality.
Implementation Method 1
light generated in the light source is converted through the diffuser sheet into white light
Data Source
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AI summary
A nanophosphor sheet is presented. The nanophosphor sheet may include a base layer, a plurality of core-shell phosphors dispersed in the base layer, and a coating layer surrounding at least one core-shell phosphor among the plurality of core-shell phosphors. Also presented is a backlight device that includes a light source emitting light, a light guide plate receiving the light, and a plurality of core-shell phosphors positioned to receive the light and convert the light to white light. The core-shell phosphors may be incorporated into the light guide plate or be positioned on the light guide plate as a separate layer.