Backlight Module Thermal Expansion Management
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Solution Overview
Problem
Existing backlight modules suffer from the light guide plate being fused and deformed due to high temperatures, leading to reduced backlight quality and reliability, as the distance between the light guide plate and the light source is too close, causing thermal expansion and potential irreversible deformation.
Innovation Solution
A backlight module design that incorporates positioning assemblies with guide surfaces and cylindrical or polygonal positioning elements, allowing the light guide plate to move away from the light strip under thermal expansion, maintaining a safe distance to prevent fusion and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the distance from the light guide plate to the LED surfaces is reduced to 0.3-0.5 mm, then the backlight intensity is improved, but the light guide plate will be fused and deformed due to high temperature
Solution Approach 1:
The positioning assembly allows the light guide plate to dynamically adjust its position relative to the light strip. The light guide plate can move along the guide surface in response to thermal expansion, maintaining an optimal distance that prevents fusion while ensuring sufficient light intensity. This dynamic adjustment mechanism resolves the contradiction between needing close proximity for brightness and needing distance for thermal safety.
Solution Approach 2:
The system changes the distance parameter between the light guide plate and light strip based on temperature conditions. Through the positioning assembly with guide surfaces, the distance is adjusted from a fixed value to a variable parameter that adapts to thermal conditions, allowing the plate to move away when heated and return when cooled, thus preventing fusion while maintaining backlight quality.
2Volume of moving object
If the light guide plate is placed close to the light strip for compact design, then the device size is reduced, but the light guide plate will deform under high temperature
Solution Approach 1:
The positioning assembly provides dynamic thermal compensation by allowing the light guide plate to move along the guide surface when thermal expansion occurs. This dynamic mechanism enables the system to maintain a compact overall structure while accommodating temperature-induced dimensional changes, preventing deformation without requiring a larger design margin.
3Strength
If the light guide plate is allowed to expand freely under thermal stress, then the material stress is reduced, but the position and backlight quality become unstable
Solution Approach 1:
The positioning assembly acts as an intermediary mechanism between the light guide plate and the housing. It provides a controlled path for thermal expansion through the guide surface, allowing the plate to expand in a predetermined direction while maintaining stable positioning. This intermediary structure converts uncontrolled free expansion into controlled movement, simultaneously reducing material stress and maintaining position stability.
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 increases the distance between the light guide plate and the light strip, preventing fusion and enhancing the stability and reliability of the backlight module, while maintaining a consistent backlight effect.
Implementation Method 1
the temperature of the surfaces of the LEDs is extremely high, and when the LEDs drive a large current, light energy radiated by the surfaces of the LEDs will be increased and may fuse the light guide plate. Particularly, in an environment over 40°, the temperature of the light guide plate near the light strip will be greatly increased
Implementation Method 2
L3 is a single-sided expansion value of the light guide plate in a first direction of the first plane under a target expansion coefficient, L4 is a single-sided expansion value of the light guide plate in the first direction under a critical expansion coefficient
Data Source
AI summary
A backlight module and a displaying device. The backlight module comprises a backplane, a reflector plate and a light guide plate that are disposed in sequence, a light strip disposed on a first side of the light guide plate, and a plurality of positioning assemblies disposed at two ends of the first side of the light guide plate respectively, wherein each light guide assembly comprises a positioning element disposed on the backplane and a guide surface disposed at a corner of the first side of the light guide plate. The positioning assemblies are disposed on the first side, where the light strip is located, of the light guide plate, such that the light guide plate will be driven to move away from support members under a reactive force of the positioning elements when expanding.