Flexible Light-Emitting Module Bump Design for Connection Reliability
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Solution Overview
Problem
Light-emitting modules with flexible substrates and LEDs face challenges in maintaining connection reliability when bent, particularly due to the risk of disconnection or short-circuiting of circuit patterns.
Innovation Solution
A light-emitting module design featuring light transmissive films with conductor patterns and a resin layer that secures the LEDs, using bumps to maintain electrical connection reliability by ensuring a sufficient vertical distance between the conductor pattern and the LEDs, even when the module is curved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the light-emitting module is made flexible to enable curved or bent usage, then adaptability and ease of operation are improved, but connection reliability deteriorates due to disconnection or short-circuiting risks
Solution Approach 1:
The patent introduces a vertical dimension by forming bumps on the conductor pattern that protrude toward the light-emitting element. This vertical protrusion creates a physical barrier that prevents short-circuiting when the module is bent, thus maintaining reliability while preserving flexibility. The bump structure adds a height dimension (H1) that separates the conductor pattern from the light-emitting element surface.
Solution Approach 2:
The bumps are formed in advance on the conductor pattern before the light-emitting module is assembled. This preliminary action creates a pre-positioned protective structure that will prevent short-circuiting during future bending operations. The bumps are specifically designed to protrude by a predetermined height (H1) to ensure adequate clearance during curvature.
2Reliability
If the vertical distance between conductor pattern and light-emitting element is increased to prevent short-circuiting, then connection reliability is improved, but device complexity increases
Solution Approach 1:
Instead of increasing the vertical distance uniformly across the entire module, the patent applies the bump structure only at specific locations where conductor patterns are present. The bumps are formed locally on the conductor pattern in the region overlapping with the light-emitting element, creating protection only where short-circuiting risk exists. This localized approach maintains simplicity in non-critical areas while ensuring reliability where needed.
Data Source
AI summary
A light-emitting module includes: a first flexible insulating substrate having a plurality of conductor patterns formed on a surface; and a light-emitting element having a first electrode placed in a first region on a surface facing the first insulating substrate and connected to a first conductor pattern out of the plurality of conductor patterns through a first bump, and a second electrode placed in a second region different from the first region on a surface facing the first insulating substrate and connected to a second conductor pattern different from the first conductor pattern through a second bump, wherein a ratio of a distance from the first region to a contact point between the first bump and the first conductor pattern against a distance from the first electrode to a position where an outer edge of the first conductor pattern intersects with an outer edge of the second region is equal to or greater than 0.1.