Backlight Module Phosphor Thermal Isolation via Light Guide Plate
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Solution Overview
Problem
Conventional backlight modules suffer from thermal degradation of phosphors due to direct heat transmission from LEDs, affecting the gray tone and color coordinate of white light, leading to reduced image display quality and phosphor life.
Innovation Solution
A phosphor layer structure is placed between the light entrance surface of a light guide plate and the backlight source, separated by a specific distance to prevent direct heat transfer, using phosphor tape or sheets with specific phosphor concentrations to maintain optimal color coordinates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phosphors are packaged directly with LEDs to generate white light, then light emission efficiency is improved, but thermal degradation occurs affecting color coordinate and gray tone
Solution Approach 1:
A light guide plate is introduced as an intermediary component between the LED and phosphor. The light guide plate guides light from the LED to the phosphor while physically separating the heat source from the phosphor, preventing direct thermal contact and allowing efficient light transmission without thermal degradation of the phosphor.
Solution Approach 2:
The phosphor is repositioned from direct contact with the LED to a location above the LED, separated by the light guide plate thickness. This spatial reconfiguration in the vertical dimension maintains optical coupling while introducing thermal isolation, resolving the contradiction between light efficiency and thermal damage.
2Productivity
If phosphors are placed close to the backlight source for efficient excitation, then light generation efficiency is improved, but heat transmission degrades phosphor performance
Solution Approach 1:
The light guide plate serves as a mediator that transmits excitation light from the backlight source to the phosphor while blocking direct thermal transmission. This allows the phosphor to be positioned close enough for efficient excitation while maintaining thermal isolation that protects phosphor longevity.
Solution Approach 2:
The light guide plate creates different thermal environments in different regions: the region near the backlight source remains hot for efficient phosphor excitation, while the phosphor region maintains lower temperature through thermal isolation, allowing both high efficiency and long life simultaneously.
3Manufacturing precision
If phosphor concentration is increased to improve color coordinate precision, then image display quality is improved, but thermal sensitivity increases
Solution Approach 1:
The light guide plate acts as a thermal barrier that protects high-concentration phosphor layers from excessive heat. This allows optimization of phosphor concentration for precise color coordinates without the usual thermal side effects, as the intermediary blocks heat transmission to the phosphor.
Solution Approach 2:
The invention enables changes in phosphor concentration parameters (increasing to 7-8% for different color coordinates) without the conventional thermal penalties. The light guide plate decouples the relationship between phosphor concentration and thermal degradation, allowing independent optimization of color 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 design effectively prevents thermal degradation, enhancing image display quality and phosphor efficiency while prolonging their lifespan.
Implementation Method 1
a phosphor layer structure... for receiving the light emitted by the backlight source to generate the white light
Implementation Method 2
utilizing a backlight module to provide light with sufficient brightness and uniform distribution to the liquid crystal display device
Data Source
AI summary
A backlight module is used for providing white light to a liquid crystal panel. The backlight module includes a light guide plate, a backlight source, and a phosphor layer structure. The light guide plate has a light entrance surface. The backlight source is disposed on a position corresponding to the light entrance surface of the light guide plate for emitting light. The phosphor layer structure is disposed between the backlight source and the light entrance surface of the light guide plate and is away from the backlight source by a specific distance, for receiving the light emitted by the backlight source to generate the white light.