Backlight Module Membrane Hanger Curved Stress Distribution
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Solution Overview
Problem
Existing backlight modules in liquid crystal display devices suffer from stress concentration at the membrane hanger and back plate connection, leading to potential damage or breakage during device transportation due to vibrations.
Innovation Solution
A backlight module design featuring a back plate with a protruded hanger and a membrane with a matching inwardly curved arc-shaped hole, along with a plastic frame that presses the membrane against the back plate, disperses stress by increasing the contact area through an outwardly convex arc-shaped surface and inwardly curved arc-shaped stressed surface, and includes a clearance fit to prevent thermal arching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the membrane hanger and back plate are connected with a simple fit structure, then the device complexity is reduced, but stress concentration occurs leading to potential damage during transportation
Solution Approach 1:
The patent applies curvature by designing the back plate hanger with an outwardly convex arc-shaped surface and the membrane hanging hole with an inwardly curved arc-shaped stressed surface. This curved interface increases the contact area between the hanger and membrane, distributing stress more evenly and preventing stress concentration that would occur with a simple flat fit structure.
Solution Approach 2:
The patent implements nesting by fitting the back plate hanger into the membrane hanging hole, creating a nested connection structure. The hanger is inserted through the hanging hole and secured with adhesive, forming a nested arrangement that provides both mechanical support and stress distribution.
2Strength
If the membrane hanger and membrane hanging hole are tightly fitted, then the fixation strength is improved, but thermal expansion causes arching and deformation
Solution Approach 1:
The patent applies local quality by creating different fit characteristics in different regions of the connection. The arc-shaped stressed surface provides a tighter local fit for stress distribution, while the overall clearance fit (0.5-1mm) maintains flexibility for thermal expansion. This localized differentiation allows the connection to be both strong and thermally stable.
Solution Approach 2:
The patent changes the fit parameter from a tight interference fit to a clearance fit with specific dimensional tolerances (0.5-1mm clearance). This parameter change allows the membrane and hanger to move slightly relative to each other during thermal expansion, preventing arching while maintaining adequate fixation strength through the arc-shaped contact surface.
3Stress or pressure
If the contact area between hanger and membrane is increased, then stress distribution is improved, but the manufacturing precision requirements are increased
Solution Approach 1:
The curved arc-shaped surfaces provide a natural stress-distributing geometry that is more tolerant to manufacturing variations than flat surfaces. The curvature allows for gradual stress distribution across the contact area, reducing the need for extremely precise flatness control while still achieving effective stress management.
Solution Approach 2:
The patent specifies a clearance fit range of 0.5-1mm between the hanger and hanging hole, which provides a tolerance band that accommodates manufacturing variations. This parameter specification allows for practical manufacturing while still achieving adequate contact area for stress distribution through the arc-shaped surfaces.
Data Source
AI summary
The present disclosure provides a backlight module and a display device. In one embodiment, a backlight module includes a back plate, a plastic frame, and a membrane provided between the back plate and the plastic frame. The back plate has a bearing surface for supporting a membrane, a back plate hanger being protruded from the bearing surface. The plastic frame has: a pressing surface for pressing the membrane against the back plate, and a support surface substantially perpendicular to the pressing surface. A membrane hanging hole for fitting the back plate hanger therein is formed at a margin of the membrane, and the back plate hanger is fitted in the membrane hanging hole. The back plate hanger has an outwardly convex arc-shaped surface facing towards the support surface, and the membrane hanging hole has an inwardly curved arc-shaped stressed surface that matches the outwardly convex arc-shaped surface.