Surface Light Source Reflector Segmentation for Thermal Wrinkle Suppression
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Solution Overview
Problem
Surface light source devices with reflective sheets experience wrinkles due to thermal expansion, leading to non-uniform luminance distribution caused by the adhesive attachment method, which fails to absorb expansion effectively.
Innovation Solution
The surface light source device employs a reflector with a first and second reflective sheet that are shiftable relative to each other via engagement pieces and engaged portions, allowing thermal expansion to be absorbed without edge turning and improving assembly workability by being installed as a unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the reflective sheet is adhered by double-sided adhesive sheets at multiple locations, then the reflective sheet is fixed to the LED substrate, but thermal expansion causes wrinkles and non-uniform luminance distribution
Solution Approach 1:
The reflective sheet is divided into multiple segments (first reflective sheet, second reflective sheet, third reflective sheet) that can independently expand and contract. This segmentation allows each segment to accommodate thermal expansion separately, preventing wrinkles and maintaining luminance uniformity while still being fixed to the substrate through adhesive sheets at multiple locations.
2Area of stationary object
If the reflective sheet is divided into multiple parts with overlapping portions, then coverage is improved, but thermal expansion causes wrinkles at the overlapping areas
Solution Approach 1:
The overlapping portions of the divided reflective sheets are designed to be non-adhered, allowing them to dynamically adjust their positions during thermal expansion and contraction. This dynamic design prevents the formation of wrinkles at the overlapping areas while maintaining complete coverage of the LED substrate.
3Stability of the object's composition
If adhesive sheets are used to suppress lifting of overlapping portions, then the reflective sheet remains in place, but thermal expansion still causes wrinkles
Solution Approach 1:
The reflective sheet is segmented into multiple parts with non-adhered overlapping portions. This segmentation allows the overlapping areas to move freely during thermal expansion without being constrained by adhesive, thereby preventing wrinkles while maintaining overall position stability through adhesive attachment at other locations.
4Ease of manufacture
If the reflective sheet is made as a single piece, then assembly is simpler, but thermal expansion causes wrinkles and edge turning
Solution Approach 1:
The reflective sheet is divided into multiple segments that can be separately handled and assembled. Each segment independently accommodates thermal expansion, preventing wrinkles and edge turning. The segmented design maintains ease of manufacture by allowing modular assembly while solving the thermal expansion problem that plagues single-piece designs.
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
This configuration effectively suppresses wrinkles and maintains even luminance distribution by allowing positional shift of the reflective sheets during thermal expansion, enhancing assembly efficiency and preventing edge turning.
Implementation Method 1
expansion and contraction occur in the reflective sheet due to temperature changes
Data Source
Figure 1~2
Figure 3~4
Figure 5~6B
AI summary
A surface light source device comprises: a plurality of light sources configured to emit light toward a light exit surface of the surface light source device; a holding member having an installation surface on which the light sources are installed; and a reflector having a plurality of openings that expose the light sources, respectively, the reflector being arranged to cover the installation surface of the holding member, the reflector including a first reflective sheet having an engagement piece at a peripheral portion of the first reflective sheet and a second reflective sheet adjacent to the first reflective sheet and having an engaged portion that is shiftably engaged with the engagement piece.