Thermoplastic Light Passing Structure for Lighting Device Safety
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Solution Overview
Problem
Lighting devices operating on non-isolated power supplies or at voltages of at least 65 volts face challenges in meeting UL 1598 standards without using glass barriers, as glass materials are expensive and prone to breaking.
Innovation Solution
The use of UL 94 5VA-rated or UL 94 V0-rated thermoplastic materials for the light passing structure in the housing of lighting devices, which are substantially transparent and pass the UL 94 5VA 5-inch flame test, allowing for compliance with UL 1598 standards without the need for glass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass materials are used for the light passing structure, then safety requirements (UL 1598 standards) are met, but cost increases and fragility occurs
Solution Approach 1:
The patent changes the material parameter from glass to thermoplastic materials (such as polycarbonate) that can achieve UL 94 5VA or UL 94 V0 ratings. This parameter change allows the light passing structure to meet safety standards while being more cost-effective and less fragile than glass
Solution Approach 2:
The patent employs inexpensive thermoplastic materials that can be easily manufactured and replaced if needed, rather than using expensive glass. These thermoplastic materials provide adequate safety performance at lower cost and with better manufacturability
2Reliability
If glass materials are used for the light passing structure, then safety requirements are met, but the material is prone to breaking during transit and installation
Solution Approach 1:
The patent changes the material parameter from glass to thermoplastic materials that possess both safety compliance (UL 94 5VA or UL 94 V0 ratings) and high impact resistance. This parameter change simultaneously improves strength while maintaining safety requirements
Solution Approach 2:
The patent uses thermoplastic materials that combine the necessary safety properties with mechanical strength and impact resistance, creating a composite solution that meets both safety and durability requirements without the fragility of glass
3Use of energy by moving object
If a barrier is made transparent for energy efficiency, then light transmission is improved, but safety protection may be compromised
Solution Approach 1:
The patent changes the material parameter to thermoplastic materials that can simultaneously achieve high transparency (for energy efficiency) and high safety ratings (UL 94 5VA or UL 94 V0). This parameter change resolves the contradiction by finding materials that excel at both transparency and safety
Solution Approach 2:
The patent employs thermoplastic materials that serve multiple functions simultaneously: they provide safety protection (meeting UL standards), maintain high transparency (for energy efficiency), and offer impact resistance. This multi-functionality resolves the contradiction between transparency and safety
Data Source
AI summary
A lighting device comprising at least one solid state light emitting light source, a power supply and a housing. The light source(s), and optionally also the power supply, is/are positioned within the housing. The power supply is configured to supply power to the light source(s). The housing comprises at least one substantially transparent light passing structure which comprises at least one thermoplastic material. When power is supplied to the light source, at least a portion of the light emitted by the source light passes through the light passing structure.