Phosphor Coating for Irregular Surfaces
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Solution Overview
Problem
Existing methods fail to uniformly coat phosphor layers on microstructured and irregular surfaces, such as those found in microcavity plasma devices, which is essential for efficient light emission and protection of phosphor particles from microplasma.
Innovation Solution
A method involving the deposition of a thin glass or polymer layer with phosphor particles, followed by sequential baking to encapsulate the phosphors, allowing for uniform coating on complex structures and protecting the phosphors from the microplasma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphor particles are blast-embedded into substrate craters, then phosphor particles are secured on the substrate, but the coating uniformity on microstructured and irregular surfaces deteriorates
Solution Approach 1:
A binder layer is applied to the substrate surface before phosphor particles are introduced. This preliminary action creates a uniform coating matrix that can accommodate microstructured and irregular surfaces, allowing phosphor particles to be embedded uniformly throughout the binder rather than requiring uniform substrate craters for retention
Solution Approach 2:
The invention creates a composite phosphor-binder coating where phosphor particles are dispersed within a binder matrix. This composite structure provides both particle retention (through the binder's adhesive properties) and coating uniformity (through the binder's ability to conform to irregular surfaces), resolving the contradiction between these two requirements
2Reliability
If phosphor particles are embedded in thick glass or plastic layers, then phosphor particles are protected from microplasma, but light emission efficiency deteriorates due to VUV photon absorption
Solution Approach 1:
The invention uses a thin binder film (rather than thick glass or plastic layers) to encapsulate and protect phosphor particles. This thin film provides protection from microplasma while minimizing VUV photon absorption, as the reduced material thickness allows more photons to reach the phosphor particles for efficient light emission
Solution Approach 2:
The invention changes the thickness parameter of the encapsulating layer from millimeters (thick glass/plastic) to micrometers (thin binder film). This parameter change maintains protection functionality while dramatically improving light emission efficiency by reducing VUV photon absorption in the encapsulating material
3Ease of manufacture
If phosphor layers are applied to irregular surfaces using conventional methods, then phosphor coating is achieved, but coating uniformity deteriorates on microstructured surfaces
Solution Approach 1:
The binder material is designed to exhibit local adaptability, conforming to the specific geometry of microstructured and irregular surfaces. This allows the phosphor coating to maintain uniformity locally across varying surface topographies, achieving both ease of manufacture and coating uniformity
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 method achieves uniform, thin phosphor coatings on microstructured surfaces, enhancing the optical properties and structural integrity of microcavity plasma devices while protecting the phosphors from damage.
Implementation Method 1
a glass or polymer layer having a substantially uniform thickness and phosphor particles, wherein the phosphor particles are at least partially encapsulated by the glass or polymer layer
Implementation Method 2
Phosphors are compounds that exhibit a sustained glow (phosphorescence) in response to the absorption of an energized particle, such as an electron or a photon
Data Source
AI summary
Microstructured, irregular surfaces pose special challenges but coatings of the invention can uniformly coat irregular and microstructured surfaces with one or more thin layers of phosphor. Preferred embodiment coatings are used in microcavity plasma devices and the substrate is, for example, a device electrode with a patterned and microstructured dielectric surface. A method for forming a thin encapsulated phosphor coating of the invention applies a uniform paste of metal or polymer layer to the substrate. In another embodiment, a low temperature melting point metal is deposited on the substrate. Polymer particles are deposited on a metal layer, or a mixture of a phosphor particles and a solvent are deposited onto the uniform glass, metal or polymer layer. Sequential soft and hard baking with temperatures controlled to drive off the solvent will then soften or melt the lowest melting point constituents of the glass, metal or polymer layer, partially or fully embed the phosphor particles into glass, polymer, or metal layers, which partially or fully encapsulate the phosphor particles and/or serve to anchor the particles to a surface.