Light Unit Resin Filling for Thermal Expansion and Hot Spot Control
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Solution Overview
Problem
Light Emitting Diodes (LEDs) in light units for Liquid Crystal Displays (LCDs) are prone to damage due to thermal expansion differences between components, leading to hot spots and reduced optical efficiency.
Innovation Solution
A light unit with a light guide member featuring reception grooves filled with a fluid resin material, including UV-curing resin and diffusion beads, to manage thermal expansion and enhance light diffusion, scattering, and refracting characteristics, reducing hot spots and improving optical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If LEDs are inserted into concave holes formed at a light guide plate, then uniform surface light emission can be achieved, but hot spots occur due to heat at the surface near the LED causing brightness spots
Solution Approach 1:
A resin material is introduced as an intermediary substance filling the concave hole between the LED and the light guide plate. This resin layer absorbs and diffuses the heat and light from the LED, preventing direct thermal contact and reducing hot spot formation while maintaining uniform light emission across the display surface.
2Illumination intensity
If LEDs are arranged on a PCB and inserted into a light guide plate, then surface light emission can be achieved, but the LED is damaged by the difference between the thermal expansion rates of components
Solution Approach 1:
The resin material serves as a buffer layer that accommodates differential thermal expansion between the LED, PCB, and light guide plate. This intermediary substance absorbs thermal stress and prevents mechanical damage to the LED caused by mismatched expansion rates during temperature cycling.
Solution Approach 2:
The resin material is selected with specific thermal and mechanical properties that match or bridge the gap between the PCB and light guide plate expansion characteristics. By changing the material parameters of the filling substance, thermal stress is reduced and LED reliability is improved.
3Illumination intensity
If a light guide plate transmits light from LEDs, then illumination can be provided, but optical efficiency is reduced due to hot spots and light loss
Solution Approach 1:
The resin layer acts as an optical intermediary that diffuses and redistributes light from the LED source. This intermediary medium reduces light concentration at hot spots and improves overall light extraction efficiency, thereby reducing energy loss and enhancing optical efficiency.
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 LED damage from thermal expansion and significantly reduces hot spots while improving light extraction and transmission efficiency, ensuring uniform illumination and reliability.
Implementation Method 1
the light diffusing, refracting and scattering characteristics of the resin material
Implementation Method 2
the light diffusing, refracting and scattering characteristics of the resin material
Implementation Method 3
the light diffusing, refracting and scattering characteristics of the resin material
Implementation Method 4
The resin material may include a UV-curing resin material
Data Source
AI summary
A light unit is provided. The light unit includes a PCB mounted with a plurality of LEDs, and a light guide member having a plurality of reception grooves piercing therethrough and receiving the LEDs, wherein the light guide member includes one surface and the other surface opposite to the one surface, and the one surface of the light guide member is further coated with the resin material. The reception grooves are formed in the light guide member and are filled with a fluid resin material, thus preventing the damage to the LED caused by the difference between the thermal expansion rates of the components such as the light guide member, the reflection film and the PCB.