Optimized Phosphor Alignment for Efficient Illumination Devices
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Summary
Problems
The existing illumination devices using wavelength conversion elements have low light conversion rates and inefficient extraction of secondary light, leading to light loss and uneven brightness, due to inadequate consideration of phosphor alignment and emission orientation.
Innovation solutions
An illumination device with a wavelength conversion element that includes a phosphor layer with anisotropic phosphors aligned along a specific direction, where the angle between the transition dipole moment of the phosphors and the delayed phase axis of polymer molecules is optimized to enhance the extraction efficiency of secondary light, which is polarized and scattered in a direction parallel to the alignment direction.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If a phosphor layer is used as a wavelength conversion element, then wavelength conversion is achieved, but light conversion rate is low and light loss increases
Why choose this principle:
The patent changes the orientation parameter of phosphors in the phosphor layer by controlling crystal growth direction during fabrication. By aligning phosphors with their c-axis perpendicular to the sapphire substrate surface, the emission orientation is optimized to extract more secondary light, thereby reducing light loss and improving light conversion rate.
Principle concept:
If phosphors are randomly oriented in the phosphor layer, then manufacturing is simplified, but secondary light extraction efficiency is poor
Why choose this principle:
The patent applies local quality by creating directional alignment of phosphors specifically in the vertical orientation (c-axis perpendicular to substrate) while maintaining random distribution in lateral directions. This localized orientation control optimizes light extraction in the emission direction without complicating the overall manufacturing process.
Application Domain
Data Source
AI summary:
An illumination device with a wavelength conversion element that includes a phosphor layer with anisotropic phosphors aligned along a specific direction, where the angle between the transition dipole moment of the phosphors and the delayed phase axis of polymer molecules is optimized to enhance the extraction efficiency of secondary light, which is polarized and scattered in a direction parallel to the alignment direction.
Abstract
An illumination device includes a light source that emits primary light and a wavelength conversion element that converts at least a portion of the primary light from the light source. The wavelength conversion element includes a phosphor layer having phosphors that absorb at least a portion of the primary light from the light source to emit secondary light, which is polarized, and polymers having birefringence. The phosphors have an anisotropic structure and are aligned generally along a first direction, and the polymers have polymer molecules that are aligned generally along the first direction. An angle formed by a direction of a transition dipole moment of each of the phosphors to a delayed phase axis of each of the polymer molecules with respect to the secondary light emitted from the phosphors towards the polymer molecules is 0° to 45°.