COB LED Lighting with External Current Control
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Solution Overview
Problem
Conventional LED strip lights lack aesthetic appeal, produce uneven illumination, and waste light energy due to exposed circuit boards and poorly managed current limiting resistors, leading to reduced light intensity and lifespan.
Innovation Solution
The development of chip-on-board (COB) LED lighting devices with a substrate-mounted LED segments, a phosphor binder for uniform light emission, and external current control circuits to manage heat and prevent 'dead spots, featuring high LED density and integrated buffers for shock absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If current limiting resistors are mounted in close proximity to LEDs on the circuit board, then the circuit board layout is simplified, but the resistors generate heat that reduces LED lifespan and light output
Solution Approach 1:
The patent extracts the current limiting resistors from the circuit board and positions them externally on heat dissipation fins. This separation removes the heat-generating resistors from proximity to the LEDs, allowing the resistors to dissipate heat into the ambient environment rather than transferring it to the LEDs, thereby extending LED lifespan while maintaining manufacturing simplicity
Solution Approach 2:
The patent introduces heat dissipation fins as an intermediary structure between the current limiting resistors and the ambient environment. These fins provide a dedicated thermal pathway that mediates heat transfer from the resistors to the surrounding air, preventing heat accumulation near the LEDs while maintaining electrical functionality
2Ease of manufacture
If conventional LED strip lights use exposed circuit boards, then manufacturing is simple, but the illumination is uneven and harsh
Solution Approach 1:
The patent uses a reflective backing layer that copies and redirects light that would otherwise be absorbed by the circuit board back toward the viewing direction. This creates a virtual image of the light source, effectively doubling the perceived light output and creating more uniform illumination across the LED strip while maintaining the simple circuit board construction
Solution Approach 2:
The patent addresses the two-dimensional limitation of planar LED mounting by introducing a third dimension through the reflective backing layer. This layer reflects light back through the LED chips, effectively utilizing the z-dimension to improve light distribution and uniformity without adding complexity to the circuit board layout
3Adaptability or versatility
If LEDs are mounted directly on the circuit board, then integration is high, but the circuit board absorbs light energy reducing overall light output
Solution Approach 1:
The reflective backing layer creates a optical copy of the light path by reflecting light back through the LED chips. This allows light energy that would have been absorbed by the circuit board to be redirected and utilized, effectively increasing the overall light output without requiring changes to the integrated LED mounting structure
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 COB LED lighting devices provide even, uniform, and directed light with increased lifespan and efficiency by positioning resistors externally to the phosphor binder, ensuring proper cooling and reducing thermal impact on LEDs, thus enhancing light output and consistency.
Implementation Method 1
a phosphor binder distributed over the LED segments on the substrate
Implementation Method 2
the PCB includes an integrated buffer configured to provide shock absorbing properties to the PCB proximate the LEDs
Implementation Method 3
external current control circuits to manage heat and prevent 'dead spots, featuring high LED density and integrated buffers for shock absorption
Data Source
AI summary
COB LED lighting devices are provided having a substrate, at least one parallel-connected LED segment formed on the substrate, at least one series-connected LED groups mounted to the substrate, each of the LED groups also including at least one parallel-connected LEDs, each LED connected to a pad of the substrate, the device also including a phosphor binder distributed over the LED segments on the substrate, and a current control circuit in electrical communication with each of the LED segments, each current control circuit formed on the substrate adjacent to the LED segments, external to the phosphor binder.