Backlight Unit Position Limiting Structure for Display Assembly
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Solution Overview
Problem
Conventional side-in type backlight units experience a reduction in light incident efficiency when turned over by 180 degrees due to the light guide plate sinking and increased gap between lamp beads and the light incident surface, leading to decreased display brightness and image quality.
Innovation Solution
A backlight unit with a position limiting and fixing structure between the light guide plate and the back plate, and between the light guide plate and the lamp strip, ensures a consistent gap between the light emitting surfaces of the lamp beads and the light incident surface of the light guide plate, even when the unit is turned over, using an adhesive strip and position limiting parts to maintain optimal light incident efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber pad is provided at the upper side to limit the position of the light guide plate using gravity, then the gap between lamp beads and light incident surface is ensured in normal position, but the light incident efficiency decreases when the backlight unit is turned over by 180 degrees
Solution Approach 1:
The position limiting structure is divided into multiple independent rubber pads distributed at different locations (upper side, lower side, and side walls) rather than relying on a single rubber pad. This segmentation ensures that the light guide plate is constrained from multiple directions, maintaining stable positioning and optimal gap regardless of the backlight unit's orientation.
Solution Approach 2:
The patent introduces additional rubber pads at the lower side and side walls to counterbalance the gravitational effect when the backlight unit is turned over. These rubber pads provide opposing support forces that prevent the light guide plate from sinking, thereby maintaining the optimal gap between lamp beads and light incident surface in any orientation.
2Device complexity
If the light guide plate is allowed to move freely under gravity, then the structure is simple, but the gap between lamp beads and light incident surface changes when turned over, reducing display brightness
Solution Approach 1:
Multiple rubber pads are distributed at strategic locations (upper side, lower side, and side walls) to provide localized position limiting. This segmented approach maintains structural simplicity while ensuring the light guide plate remains stable in any orientation, preventing gap variation and maintaining display brightness.
Solution Approach 2:
Rubber pads are strategically positioned at specific locations where position limitation is most needed - the upper side for normal operation, the lower side and side walls for overturned operation. This local quality approach ensures optimal gap maintenance with minimal structural complexity.
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 ensures the highest light incident efficiency when the backlight unit is turned over, meeting design and display requirements, and maintains display brightness, thereby enhancing user experience.
Implementation Method 1
an adhesive strip arranged between the light guide plate and the back plate... two sides of the adhesive strip are adhesively connected to the light guide plate and the bottom wall respectively
Implementation Method 2
the adhesive strip includes a first adhesive layer, an elastic film layer and a second adhesive layer, which are sequentially superposed together
Data Source
AI summary
A backlight unit includes: a back plate including a bottom wall and a side wall around a periphery of the bottom wall; a lamp strip including a substrate and lamp beads on the substrate; a light guide plate on a side of the bottom wall provided with the side wall, the lamp strip being on a first side wall of the side wall, and light emitting surfaces of the lamp beads being opposite to a side surface of the light guide plate; and a position limiting and fixing structure between the light guide plate and each of the back plate and the lamp strip, for limiting and fixing a position of the lamp strip relative to the light guide plate to keep a gap between the light emitting surfaces of the lamp beads and a light incident surface of the light guide plate unchanged during turn-over of the backlight unit.