Backlight Unit Lens Fixation at Reflective Plate Edges
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Solution Overview
Problem
In direct type backlight units, the printed circuit board (PCB) and lenses lift off from the reflective plate in high temperature or high humidity environments, leading to deteriorated screen quality in curved display devices.
Innovation Solution
The PCB and lenses are fixed to the reflective plate by inserting them into openings of varying shapes and widths, with the PCB and lens widths differing to prevent lifting, and a reinforcement frame is used to maintain curvature and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the PCB and lenses are fixed to the reflective plate using equal spacing arrangement, then the manufacturing process is simple, but the lenses lift off from the edge of the reflective plate in high temperature or high humidity environments
Solution Approach 1:
The patent applies different spacing arrangements for different regions of the PCB. The first spacing is applied to LEDs at the edge of the PCB, while the second spacing (different from the first) is applied to LEDs in the interior region. This local differentiation ensures that edge LEDs are properly positioned to prevent lens lift-off in high temperature or humidity environments, while maintaining appropriate spacing for interior LEDs, thus resolving the contradiction between manufacturing simplicity and fixation reliability.
2Device complexity
If the PCB width and lens width are made equal, then the assembly process is simplified, but the lens lifts off from the edge of the reflective plate
Solution Approach 1:
The patent differentiates the width dimensions between edge lenses and interior lenses. The first width is defined for lenses at the edge of the PCB, while the second width (different from the first) is defined for lenses in the interior region. This local differentiation ensures that edge lenses maintain precise positioning on the reflective plate, preventing lift-off, while interior lenses have appropriate dimensions for their functional requirements, thus resolving the contradiction between assembly simplicity and positioning precision.
3Productivity
If a uniform spacing arrangement is used for all LEDs, then the manufacturing process is straightforward, but screen quality deteriorates due to lens lift-off
Solution Approach 1:
The patent implements a differentiated spacing strategy where edge LEDs use one spacing value and interior LEDs use another. This approach maintains manufacturing efficiency by using standardized processes for each region while achieving precise lens positioning specifically at the edge where lift-off occurs. The result is improved screen quality without significantly compromising manufacturing productivity, as the differentiation is localized to specific regions rather than requiring complex universal adjustments.
Data Source
AI summary
Disclosed is a backlight unit in which a PCB and a lens are prevented from lifting off from an edge of a reflective plate and are fixed to the reflective plate when manufacturing an LED array. Further, the display device including the same is provided. To this end, the backlight unit is configured such that the lenes disposed on the PCB and arranged so as to be spaced from each other are fixedly inserted into openings defined in the reflective plate, wherein the openings defined in different areas of the reflective plate have different shapes and widths.