Flexible LED Ribbon Substrate with Bridge-Like Segments
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Solution Overview
Problem
Existing lighting devices with linear LED modules face challenges in bending both normal and parallel to their installation plane while maintaining low ohmic resistance and mechanical robustness, especially when flexed in the lying plane, leading to potential damage to light sources and electrical connections.
Innovation Solution
A lighting device featuring a ribbon-like flexible substrate with rectangular flat laminar support structures and bridge-like flexible portions, allowing for multi-directional bending without straining the light sources or electrical connections, achieved through a combination of a dielectric substrate and conductive layers with reduced cross-sectional area, enabling flexible and robust operation even in long modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LED modules are mounted on rigid boards with meander-like FPC connections, then electrical connectivity is maintained, but the module cannot achieve small bending radiuses especially in the installation plane
Solution Approach 1:
The rigid board is segmented into multiple flat laminar support structures connected by flexible bridge portions. This segmentation allows the module to bend while maintaining structural integrity, as each flat portion can remain rigid while the bridge portions provide flexibility. The segmentation resolves the contradiction by distributing mechanical stress across multiple segments rather than requiring the entire structure to be flexible.
Solution Approach 2:
Different portions of the substrate have different mechanical properties: flat laminar support structures provide rigidity for mounting LEDs, while bridge-like portions provide flexibility for bending. This local differentiation of mechanical properties allows the module to simultaneously achieve both rigidity where needed and flexibility where needed, resolving the contradiction between strength and adaptability.
2Area of stationary object
If the module length is increased to cover larger areas, then lighting coverage is improved, but ohmic resistance of electrical lines increases leading to non-uniform current distribution
Solution Approach 1:
The electrical connection transitions from a planar two-dimensional layout to a three-dimensional path following the bridge-like portions. This dimensional change allows the electrical lines to maintain shorter effective lengths by routing through the flexible bridge portions rather than requiring long lateral connections across rigid boards, thereby reducing ohmic resistance while maintaining large lighting coverage area.
3Adaptability or versatility
If flexure is applied in the installation plane to achieve arbitrary bending, then adaptability is improved, but mechanical robustness deteriorates and light sources may be damaged
Solution Approach 1:
The module structure transitions from a static rigid configuration to a dynamic configuration where flat laminar portions can remain rigid for mounting while bridge-like portions provide controlled flexibility. This dynamic design allows the module to adapt to different installation geometries while protecting light sources, as the flexible bridge portions absorb bending stresses rather than transmitting them to the rigid mounting areas.
Data Source
Figure 1
Figure 2a~2l
Figure 3a1~3g2
AI summary
A lighting device includes a flexible ribbon-like substrate (12) with electrically-powered, e.g. LED, light radiation sources (14) thereon, as well as electrically conductive portions (16a, 16b, 16c) providing electrically conductive lines for the light radiation sources (14). Substrate (12) includes laminar support portions (120) for light radiation sources (18) arranged thereon and bridge-like portions (122) extending between said laminar support portions (120). The electrically conductive portions (16a, 16b, 16c) have at said bridge-like portions (122) a lower cross-sectional area than at laminar support portions (120), so that bridge-like portions (122) enable a multi-directional flexibility of lighting device (10).