Patterned Phosphor Coating for LED Color Consistency

The patent applies phosphor materials with different properties to different regions of the LED device. Specifically, first and second phosphor materials are applied to different areas, and the phosphor layer thickness is varied across the device surface. This local differentiation compensates for angle-dependent color variations by ensuring that light emitted at different angles passes through appropriate phosphor concentrations, thereby maintaining consistent color rendering across various viewing angles.

The patent employs a convex lens structure positioned over the LED chip. This curved optical element refracts and redirects light rays, reducing multiple internal reflections that would otherwise cause energy loss. The convex shape helps to extract light more efficiently from the LED while maintaining the color transformation function of the phosphor materials, thereby improving overall light extraction efficiency without sacrificing color generation capability.

The patent implements a non-uniform phosphor coating where the thickness and material composition vary across different regions of the LED device. This is achieved by applying first and second phosphor materials in different areas and controlling the deposition process to create thickness gradients. While this approach increases manufacturing complexity compared to a uniform coating, it effectively compensates for the CCT angle effect and maintains consistent color temperature across different viewing angles.

The patent optimizes specific parameters of the phosphor coating structure, including the thickness of phosphor layers and the spatial distribution of different phosphor materials. By carefully controlling these parameters during the manufacturing process, the device achieves consistent color rendering across various angles. The parameter optimization balances the need for color consistency with the desire to limit device complexity, ensuring that the additional structural elements are justified by the performance improvement.