Semiconductor Light Emitting Device with Enhanced Polarization
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Summary
Problems
Semiconductor light emitting devices using nonpolar or semipolar planes as growth surfaces face reduced polarization ratio due to random light extraction from rough side end surfaces, leading to decreased efficiency in applications like liquid crystal backlights and projectors.
Innovation solutions
The semiconductor light emitting device is designed with specular side end surfaces by using a substrate with a hexagonal crystalline structure and epitaxially growing a light emitting portion on a nonpolar or semipolar plane, and further enhancing the surface finish to minimize light scattering, combined with a light transmissive resin portion having a non-arrayed structure to maintain polarization integrity.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If the side end surfaces are made rough to increase light extraction quantity, then the amount of light extracted increases, but the polarization ratio decreases due to random light direction
Why choose this principle:
The patent applies different surface qualities to different regions: the light extraction surface has a rough structure to maximize light extraction quantity, while the side end surfaces maintain specular (smooth) properties to preserve polarization ratio. This local differentiation resolves the contradiction by allowing each surface to optimize for its specific function without compromising the other.
Principle concept:
If a polarizer is added to maintain polarization, then the polarization ratio is improved, but the light intensity is reduced due to absorption of orthogonal polarization components
Why choose this principle:
The patent converts the naturally random polarized light from multiple extraction points into beneficial aligned polarized light by using specular side end surfaces as reflective elements. Instead of adding a polarizer that absorbs light, the device structure itself guides and aligns the polarization through controlled reflection from smooth side surfaces, turning the multi-directional light into useful polarized light without intensity loss.
Application Domain
Data Source
AI summary:
The semiconductor light emitting device is designed with specular side end surfaces by using a substrate with a hexagonal crystalline structure and epitaxially growing a light emitting portion on a nonpolar or semipolar plane, and further enhancing the surface finish to minimize light scattering, combined with a light transmissive resin portion having a non-arrayed structure to maintain polarization integrity.
Abstract
A semiconductor light emitting device includes a substrate, and a light emitting portion that is disposed on the substrate, and includes an active layer formed of a group III nitride semiconductor using a nonpolar plane or a semipolar plane as a growth principal surface, in which side end surfaces of the active layer are specular surfaces.