LED Lamp with Elevated Planar Array for Thermal Management
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Solution Overview
Problem
LED lamps face challenges such as low maximum junction temperature, limited luminous output due to heat dissipation, unidirectional light emission, need for constant current power supply, and inefficiencies in power conversion and dimmability, which hinder their adoption as a replacement for incandescent lamps.
Innovation Solution
The design features a base with elevated LEDs connected in series on both sides of a substrate, a heat sink for efficient thermal management, and a drive circuit with a surge suppressor, rectifier, and smoothing capacitor to enhance luminous efficacy, dimmability, and thermal dissipation, allowing for efficient 360° light output and cost-effective manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LEDs are used as light source, then energy efficiency is improved, but heat dissipation becomes a limiting factor
Solution Approach 1:
The patent transitions from traditional point-source LED mounting to a planar array configuration where multiple LEDs are distributed across a two-dimensional substrate. This dimensional expansion increases the effective heat dissipation surface area while maintaining compact form factor, allowing efficient thermal management without sacrificing energy efficiency
Solution Approach 2:
The patent divides the light source into multiple discrete LED elements arranged in an array on the substrate. This segmentation allows each LED to have its own thermal management path through the substrate and heat sink structure, preventing heat accumulation and enabling sustained high-efficiency operation
2Temperature
If LEDs are mounted on heat sink, then thermal management is improved, but light output is reduced due to absorption
Solution Approach 1:
The patent introduces a transparent or translucent substrate as an intermediary between the LED array and the external environment. This substrate serves dual functions: providing mechanical support and thermal conduction path to the heat sink, while simultaneously allowing light to pass through with minimal absorption, thus resolving the conflict between thermal management and light output
Solution Approach 2:
The patent applies different material properties to different regions of the system: the substrate is made transparent/translucent in light-path regions to maximize light output, while maintaining thermal conductivity in regions contacting the heat sink for effective thermal management. This localized optimization of material properties resolves the contradiction
3Use of energy by moving object
If multiple LEDs are connected in series, then luminous efficacy is improved, but device complexity increases
Solution Approach 1:
The substrate serves multiple functions simultaneously: it acts as the mechanical mounting platform for the LED array, provides the electrical interconnection network for series/parallel configurations, and functions as part of the thermal management system by conducting heat to the heat sink. This multi-functionality reduces overall device complexity despite the sophisticated LED interconnections
4Reliability
If drive circuit is added for constant current, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines the drive circuit with the power supply unit, integrating constant current regulation functionality into the existing power conversion stage. This merging approach provides reliable LED driving without adding a separate, complex control circuit stage, thus improving reliability while minimizing the increase in device complexity
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 achieves high system luminous efficacy, efficient thermal management, and dimmability, making it a direct replacement for low-power incandescent lamps with improved reliability and efficiency.
Implementation Method 1
Heat dissipation is a function of the heat sink surface area, the thermal conductivity of the different media and interfaces and the temperature difference between the heat sink and ambient temperature
Implementation Method 2
LEDs generate heat at a rate equal to the product of the voltage drop VD and the drive current ID
Implementation Method 3
high intensity LEDs started emerging, including the white LED
Implementation Method 4
Heat dissipation is a function of the heat sink surface area, the thermal conductivity of the different media and interfaces and the temperature difference between the heat sink and ambient temperature
Data Source
AI summary
An LED lamp that can take the place of incandescent lamps. An elevated light source is positioned above a screw-type base. A first plurality of LEDs is connected in a series on one side of a flat substrate and a second plurality of LEDs, equal in number to the first, is connected in series on an opposite side of the substrate. Each LED of the first and second plurality of LEDs is mounted proximate a heat sink and a drive circuit is provided for the LEDs, with the drive circuit being located proximate and electrically connected to the screw base.