Backlight Module Holder Maintains LED Gap During Thermal Expansion
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Solution Overview
Problem
In side-light type backlight modules, the gap between the light emitting diode and the light guide plate varies due to thermal expansion, leading to reduced luminance and uniformity, as existing mechanisms fail to maintain a minimal gap during temperature changes.
Innovation Solution
A holder with a retainer and fixing component is used between the back plate and the light guide plate to constrain the light source module, allowing it to move with the light guide plate and maintain a stable gap, thereby preventing displacement and ensuring consistent light efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the gap between the light emitting diode and the light guide plate is reduced to increase light incident efficiency, then luminance and uniformity are improved, but the structure becomes more difficult to assemble and the gap is hard to control precisely in mass production
Solution Approach 1:
A holder is introduced as an intermediary component between the light guide plate and the light emitting diode light bar. The holder includes a retainer that engages with a fastening component on the light guide plate and a fixing component that holds the light emitting diode, thereby mediating the spatial relationship and maintaining a precise gap without requiring direct engagement between the light guide plate and the light emitting diode.
Solution Approach 2:
The fixing mechanism is segmented into multiple independent components: the holder, the retainer, the fastening component, and the fixing component. This segmentation allows each component to perform its specific function independently, making the overall assembly process more manageable and the gap control more precise.
2Stability of the object's composition
If the light guide plate is fixed rigidly to the back plate, then positioning is stable, but thermal expansion causes the light emitting diode to be pressed and displaced, increasing the gap and reducing light incident efficiency
Solution Approach 1:
The holder is designed with dynamic characteristics, where the retainer can move relative to the light guide plate along the lateral side to accommodate thermal expansion. The pressing component applies a controlled pressing force that allows for dynamic adjustment, enabling the structure to maintain stable positioning while adapting to temperature variations and preventing excessive gap formation.
3Adaptability or versatility
If the light emitting diode light bar is allowed to move freely, then thermal expansion is accommodated, but the light source displaces from its original position, increasing the gap and reducing incident efficiency
Solution Approach 1:
The holder changes the physical parameters of the system by introducing a controlled pressing force through the pressing component. This pressing force constrains the light emitting diode light bar within a specific range, allowing thermal expansion to occur without excessive displacement. The parameter of pressing force is optimized to balance between accommodating thermal expansion and maintaining positioning 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
The solution effectively maintains a stable gap between the light source module and the light guide plate across varying temperatures, stabilizing luminance and preventing the light source from being pressed, thus maintaining high efficiency and reducing luminance variations.
Implementation Method 1
the light guide plate suffers the temperature variation from 0° C. to 60° C. Linear thermal expansion coefficient of the ordinary light guide plate 1 is around 83/(106K). If the 20 inch display panel suffers the temperature variation of 25 degrees in centigrade, length of the lateral side S0 of the light guide plate 1 expands to 445.92 mm.
Data Source
AI summary
A holder is disposed at a side of a back light module adjacent to a light incident side of a light guide plate (LGP). A light source module is fixed on a wall of the holder that faces the light incident side. A holder engager on a side wall of the LGP engages with an LGP retainer of the holder. When the LGP expands or contracts due to changes of temperature, the holder and the light source module move with the side of the LGP, thereby a gap between the light source module and the light incident side is maintained and the luminance of the backlight module is stabilized.