Backlight Frame Positioning Grooves for Thermal Expansion
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Solution Overview
Problem
Curved surface display devices face issues with curvature accuracy and vibration reliability due to thermal expansion differences between optical films and metal components, leading to wrinkles, light leakage, and assembly tolerance problems, especially in high-temperature and high-humidity environments.
Innovation Solution
A backlight assembly with a supporting frame and optical film design that includes positioning grooves and protrusions to accommodate thermal expansion, ensuring accurate positioning and minimizing assembly tolerance, thereby maintaining display quality and reliability across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the optical film is tightly fixed to the metal components, then assembly tolerance is minimized, but thermal expansion differences cause wrinkles and light leakage in high-temperature environments
Solution Approach 1:
The patent changes the spatial parameters of the positioning structure by introducing positioning grooves with specific cross-sectional shapes (U-shape, L-shape, or T-shape) and controlling the gap distances between the optical film edge and the positioning groove walls. The gap distances are specifically designed: first gap (1-5mm) on the long side and second gap (5-10mm) on the short side, allowing thermal expansion while maintaining positioning accuracy.
Solution Approach 2:
The positioning groove acts as an intermediary structure between the optical film and the frame. Instead of direct contact fixation, the groove provides a controlled interface that accommodates thermal expansion through designed gaps, mediating between the need for secure positioning and the need to accommodate dimensional changes.
2Reliability
If the optical film is loosely positioned, then thermal expansion is accommodated, but curvature accuracy and assembly tolerance deteriorate
Solution Approach 1:
The patent optimizes the geometric parameters of the positioning groove including its cross-sectional shape (U-shape, L-shape, or T-shape), the depth of the groove, and the specific gap distances (first gap 1-5mm, second gap 5-10mm). These parameter optimizations ensure the optical film can expand while maintaining curvature accuracy within acceptable tolerances.
Solution Approach 2:
Different regions of the optical film edge are treated differently with asymmetric gap arrangements. The long side has smaller gaps (1-5mm) while the short side has larger gaps (5-10mm), providing localized quality control that accommodates thermal expansion patterns while maintaining overall curvature accuracy.
3Manufacturing precision
If rigid fixation structures are used, then positioning accuracy is improved, but vibration reliability decreases due to thermal stress
Solution Approach 1:
The patent changes the structural parameters from rigid direct contact to a semi-rigid groove-based system with controlled gaps. The positioning groove cross-sectional shape (U-shape, L-shape, or T-shape) and gap dimensions (1-10mm ranges) are optimized to provide positioning accuracy while reducing thermal stress accumulation that would compromise vibration reliability.
Solution Approach 2:
The positioning groove structure provides beforehand cushioning by pre-designing gap spaces that absorb thermal expansion stresses before they can cause damage. This preventive design cushions the optical film and frame from thermal stress during temperature variations, maintaining vibration reliability.
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 enhances curvature accuracy and vibration reliability by allowing for thermal expansion and contraction without causing wrinkles or light leakage, ensuring consistent display performance in diverse environmental conditions.
Implementation Method 1
thermal expansion differences between optical films and metal components
Implementation Method 2
thermal expansion differences between optical films and metal components
Data Source
AI summary
A backlight assembly includes a first sub-optical film with first edge portions, and a supporting frame including a first supporting portion which includes rims. At least one rim includes a first positioning groove and second positioning grooves, the first edge portion includes a first positioning portion in the first positioning groove and second positioning portions in the second positioning grooves; a difference between sizes of the first positioning groove and the first positioning portion is a first space, a difference between a size of each second positioning groove and that of the second positioning portion is a second space greater than the first space; the first edge portions include a first sub-edge portion, the first positioning portion is located at a midpoint of the first sub-edge portion, and the second positioning portions are distributed on both sides of the first positioning portion.