Light-Emitting Device With Front-Surface Thermal Fuse and Back-Surface Heat Dissipation
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Solution Overview
Problem
Conventional LED lighting systems with thermal fuses on the back surface of printed-circuit boards have limited heat dissipation areas, leading to decreased reliability and heat dissipation effectiveness.
Innovation Solution
A light-emitting device design with a heat-sensitive circuit breaker mounted on the front surface of the substrate, connected to a metal film, and covered by a light-proof cover, allowing for a larger heat dissipating member on the back surface to enhance heat dissipation while preventing thermal fuse interruption by light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thermal fuse is mounted on the back surface of the printed-circuit board, then the circuit protection function is achieved, but the heat dissipation area is limited and heat dissipation effect decreases
Solution Approach 1:
The patent moves the heat-sensitive circuit breaker from the back surface to the front surface of the substrate, utilizing the previously unused front surface area. This dimensional relocation allows the heat dissipating member on the back surface to expand without obstruction, resolving the contradiction between circuit protection and heat dissipation area.
Solution Approach 2:
The patent separates the light-sensitive circuit breaker function from the heat dissipation function by placing them on opposite surfaces of the substrate. The circuit breaker is positioned on the front surface away from the light-emitting element, while the heat dissipating member occupies the back surface, allowing both functions to operate independently without interference.
2Reliability
If the thermal fuse is placed on the back surface, then circuit protection is provided, but the heat dissipating member area is reduced
Solution Approach 1:
By relocating the heat-sensitive circuit breaker to the front surface (another dimension/surface), the back surface becomes fully available for the heat dissipating member, maximizing heat dissipation effectiveness while maintaining overheat protection functionality through the circuit breaker on the front surface.
Solution Approach 2:
The substrate serves as an intermediary that separates the light-sensitive circuit breaker from the light-emitting element while maintaining electrical connection. This intermediary positioning allows the circuit breaker to function as a protective element without interfering with the light path or heat dissipation.
3Reliability
If the heat-sensitive circuit breaker is mounted on the front surface, then light interference is avoided, but additional structural components are needed
Solution Approach 1:
The patent extracts the light-sensitive circuit breaker from the light path area and positions it on the front surface away from the light-emitting element. This extraction eliminates the need for complex light-shielding structures while preventing false triggering, as the circuit breaker is positioned where it cannot be exposed to emitted light.
Solution Approach 2:
The patent combines the circuit breaker mounting with the existing front surface structure, integrating the protective function into the available space without adding separate complex mounting structures. The circuit breaker is mounted on the front surface utilizing existing structural elements rather than requiring additional dedicated components.
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 design improves the reliability of the light-emitting device by effectively preventing overheating and maintaining heat dissipation performance, as the heat-sensitive circuit breaker is protected from light interference and can be integrated with various materials like bimetal or shape-memory alloys for temperature-dependent operation.
Implementation Method 1
The heat sensitive circuit breaker comprises a member that is formed of bimetal or shape-memory alloy and deforms in accordance with temperature variation
Implementation Method 2
The heat sensitive circuit breaker comprises a member that is formed of bimetal or shape-memory alloy and deforms in accordance with temperature variation
Implementation Method 3
a light-proof cover that covers the heat sensitive circuit breaker to block light emitted from the light-emitting element and travelling toward the heat sensitive circuit breaker
Implementation Method 4
a heat dissipating member formed on a second surface of the substrate to dissipate heat of the substrate
Data Source
AI summary
A light-emitting device includes a substrate having a metal film on a first surface, a light-emitting element mounted on the first surface of the substrate and connected to the metal film, a heat sensitive circuit breaker mounted on the first surface of the substrate and connected to the metal film, a light-proof cover that covers the heat sensitive circuit breaker to block light emitted from the light-emitting element and travelling toward the heat sensitive circuit breaker, and a heat dissipating member formed on a second surface of the substrate to dissipate heat of the substrate, the second surface being opposite to the first surface.