Optimized Phosphor Design for High-Efficiency Light Emission
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Summary
Problems
Conventional light emitting devices using single crystal phosphors grown by the Czochralski method have high manufacturing costs and poor light extraction efficiency, especially when using powder phosphors excited with high light density, which leads to low light emission output, particularly in devices emitting red light.
Innovation solutions
A light emitting device with a substrate and a phosphor layer where monodispersed polyhedral garnet-derived phosphor particles with facets are adhered, having a median particle size of 30 μm or more, to improve heat propagation and reduce temperature quenching, thereby enhancing light emission efficiency.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If single crystal phosphors grown by the Czochralski method are used, then manufacturing precision is improved, but manufacturing cost increases and light extraction efficiency deteriorates
Why choose this principle:
The patent replaces expensive single crystal phosphors with powder phosphors that can be mass-produced through conventional ceramic methods. The powder phosphor particles, while individually smaller and less perfect, collectively provide the necessary optical performance at significantly lower manufacturing cost and with improved light extraction efficiency due to their granular structure.
Principle concept:
If single crystal phosphors grown by the Czochralski method are used, then manufacturing precision is improved, but manufacturing cost increases and light extraction efficiency deteriorates
Why choose this principle:
The patent changes the physical state parameter of the phosphor from single crystal to powder form, and optimizes particle size parameters (D50 between 45-105 μm) to achieve optimal balance between heat propagation and light extraction. This parameter optimization resolves the contradiction between manufacturing ease and optical performance.
Application Domain
Data Source
AI summary:
A light emitting device with a substrate and a phosphor layer where monodispersed polyhedral garnet-derived phosphor particles with facets are adhered, having a median particle size of 30 μm or more, to improve heat propagation and reduce temperature quenching, thereby enhancing light emission efficiency.
Abstract
A light emitting device 1 includes: a substrate 30 ; and a phosphor layer 40 composed in such a manner that a large number of phosphor particles 60 are adhered onto a flat surface 32 of the substrate 30 . At least one of the phosphor particles 60 is a polyhedral phosphor particle 65 that is monodispersed, is derived from a crystal structure of garnet and has facets, and a median particle size D 50 of the polyhedral phosphor particle 65 is 30 μm or more and a maximum thickness of the phosphor layer 40 or less. It is preferable that at least one of the phosphor particles 60 adhered onto the flat surface 32 of the substrate 30 is the polyhedral phosphor particle 65 that is monodispersed, is derived from the crystal structure of the garnet, and has the facets.