Light Emitting Device Wavelength Conversion Segmentation
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Solution Overview
Problem
Existing light emitting devices have limitations in light extraction efficiency while aiming to emit light with specific chromaticity within a desired range.
Innovation Solution
The design incorporates a light emitting element with a first wavelength conversion member and a second wavelength conversion member, where the second member covers the lateral surfaces of the first member with oblique surfaces extending outward, and a light reflecting member covers these oblique surfaces to enhance light extraction efficiency and adjust chromaticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a phosphor layer covers the lateral surfaces of the light emitting element to adjust color temperature, then chromaticity control is improved, but light extraction efficiency deteriorates
Solution Approach 1:
The device segments the wavelength conversion function into two distinct members: a first wavelength conversion member (covering the top surface) and a second wavelength conversion member (covering the lateral surfaces). This segmentation allows each member to be optimized for its specific function - the first member for color temperature control and the second member for light extraction enhancement, thereby resolving the contradiction between chromaticity control and light extraction efficiency
Solution Approach 2:
The patent applies local quality by giving different optical properties to different regions: the first wavelength conversion member has properties optimized for chromaticity adjustment, while the second wavelength conversion member has properties optimized for light extraction. The oblique surfaces on the second member are specifically designed to redirect light at optimal angles, creating local optical quality improvements without compromising overall chromaticity control
2Loss of energy
If a second wavelength conversion member covers lateral surfaces with oblique surfaces, then light extraction efficiency is improved, but device complexity increases
Solution Approach 1:
The patent merges the second wavelength conversion member with the lateral surface coverage function, combining multiple roles into a single component. The oblique surfaces are integrated directly into the second wavelength conversion member rather than being separate elements, reducing assembly complexity while maintaining light extraction efficiency
Solution Approach 2:
The oblique surfaces introduce a dimensional change by tilting the conversion surfaces at specific angles rather than using flat horizontal surfaces. This angular dimensionality allows light to be redirected more effectively toward the extraction path, improving efficiency without requiring additional complex optical elements
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
This configuration significantly increases light extraction efficiency and allows for precise adjustment of chromaticity by mixing blue, yellow, and red light components, resulting in improved light output characteristics.
Implementation Method 1
a first wavelength conversion member disposed on the light emitting element and having a lower surface bonded to the light emitting element, an upper surface opposite the lower surface, and a lateral surface connected to the upper surface, the first wavelength conversion member emitting second light when excited by the first light
Implementation Method 2
a second wavelength conversion member covering the lateral surface of the first wavelength conversion member except the upper surface of the first wavelength conversion member and having an oblique surface extending from the lateral surface of the first wavelength conversion member to the outer side, the second wavelength conversion member emitting third light when excited by at least one of the first light and the second light
Implementation Method 3
a first light reflecting member covering the oblique surface
Data Source
AI summary
A light emitting device includes: a substrate; a light emitting element disposed on the substrate; a first wavelength conversion member disposed on the light emitting element and having a lower surface bonded to the light emitting element, an upper surface opposite the lower surface, and a lateral surface that meets the upper surface; a first light reflecting member disposed on an upper surface of the substrate and covering lateral surfaces of the light emitting element; and a second wavelength conversion member disposed on the first light reflecting member, on the upper surface of the substrate, and on the lateral surface of the first wavelength conversion member without covering the upper surface of the first wavelength conversion member.