Edge-Light Light Source Module Thermal Expansion Management
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Solution Overview
Problem
In edge light type light source modules, the heat generated by the light source causes the light guide plate to expand, potentially damaging the light source unit due to their close proximity, which affects luminance efficiency.
Innovation Solution
A light source module design featuring a substrate with a light guide plate and a support system that includes an attachment member with a latch part and a holding part, where the holding part protrudes more towards the light guide plate than the light source, preventing direct contact between the expanding light guide plate and the light source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the space between the light source unit and the light guide plate is made narrow to improve light incident efficiency, then luminance requirement is satisfied, but the light guide plate expands due to heat and contacts the light source unit causing damage
Solution Approach 1:
A resin layer is introduced as an intermediary substance between the light guide plate and the light source unit. This resin layer has a linear expansion coefficient larger than that of the light guide plate, allowing it to absorb the thermal expansion of the light guide plate through differential expansion, thereby preventing contact and damage to the light source unit while maintaining narrow spacing for efficient light incidence.
Solution Approach 2:
The patent changes the thermal expansion parameter by selecting a resin material with a linear expansion coefficient specifically larger than that of the light guide plate. This parameter difference creates a protective effect where the resin expands more than the light guide plate when heated, maintaining a buffer zone that prevents the light guide plate from contacting the light source unit despite thermal expansion.
2Length of stationary object
If multiple light emitting diodes are arranged to be opposed to a side surface of the light guide plate to reduce thickness, then the apparatus becomes thinner, but heat dissipation becomes more difficult compared to direct light type
Solution Approach 1:
The resin layer serves as a thermal intermediary between the light source unit and the light guide plate. While maintaining the narrow spacing required for efficient light coupling in a thin design, the resin layer manages heat transfer by expanding differentially with temperature changes, preventing direct thermal contact that would concentrate heat at critical points and potentially damage the light source unit.
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 prevents damage to the light source by allowing the light guide plate to expand and touch the holding part first, maintaining the light source's integrity and improving luminance efficiency by reducing the risk of contact and potential damage.
Implementation Method 1
light made incident from the side surface of the light guide plate is output from one surface of the light guide plate while being diffused within the light guide plate
Implementation Method 2
the heat generated when the light source unit emits light is transmitted to the light guide plate, and the light guide plate expands by the heat from the light source unit due to high linear expansion coefficient of the light guide plate
Data Source
AI summary
A light source module includes a substrate on which a light source is mounted, a light guide plate having one surface configured to emit light made incident from a side surface of the light guide plate opposed to the light source, a support configured to support the substrate at an opposite surface opposed to the side surface of the light guide plate, and an attachment member configured to attach the substrate to the support, wherein the attachment member includes a latch part to be latched to the support and a holding part configured to hold the substrate between the opposite surface and the holding part, and a height of the holding part that is holding the substrate from a surface of the substrate is higher than a height of the light source from the surface of the substrate.