LED Package Resin Sidewalls for Uniform Light Distribution
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Solution Overview
Problem
Existing semiconductor light emitting devices face challenges in achieving uniform light distribution and maintaining brightness while increasing the spacing between devices, which affects light uniformity and production costs.
Innovation Solution
The semiconductor light emitting device incorporates a package body with concave portions and a lead frame electrically connected to LED chips, featuring a wavelength conversion layer and a transparent resin layer to enhance light radiation efficiency and protect the phosphor from environmental factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the spacing between semiconductor light emitting devices is increased, then the brightness and light uniformity are improved, but the number of devices per package is reduced which affects production efficiency
Solution Approach 1:
The patent introduces a transparent resin layer that extends in the first direction (longitudinal direction) beyond the package body, creating an additional light extraction dimension. This allows light to be emitted not only from the top surface but also from the side surfaces of the transparent resin layer, effectively increasing the light output area without increasing the device spacing.
Solution Approach 2:
The patent changes the physical state and optical properties by using a transparent resin layer with specific refractive index properties. The transparent resin layer has different refractive index than the wavelength conversion layer, creating optical parameter changes that enhance light extraction efficiency and maintain light uniformity even with reduced device density.
2Ease of manufacture
If fewer semiconductor light emitting devices are used per package, then production costs are reduced, but the light distribution uniformity may be affected
Solution Approach 1:
By extending the transparent resin layer in the longitudinal direction and allowing light extraction from side surfaces, the patent compensates for the reduced number of LED chips through increased light extraction area. This dimensional extension maintains light distribution uniformity while enabling fewer devices per package.
Solution Approach 2:
The light extraction function is segmented across multiple surfaces - the top surface and the side surfaces of the transparent resin layer all contribute to light emission. This segmentation of the light extraction path allows the system to achieve uniform illumination with fewer light sources.
3Illumination intensity
If the transparent resin layer extends beyond the package body, then light radiation efficiency is improved, but the device complexity increases
Solution Approach 1:
The transparent resin layer serves multiple functions simultaneously: it acts as a sealant for the wavelength conversion layer, provides an additional light extraction path through its extended side surfaces, and protects the internal components. This multi-functionality reduces the need for separate components, thereby reducing overall device complexity despite the extended structure.
Solution Approach 2:
The patent merges the sealing function and the light extraction function into a single transparent resin layer component. Instead of having separate sealant material and light extraction structures, the transparent resin layer performs both functions, simplifying the overall device architecture.
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 improves light radiation efficiency, maintains light uniformity even with increased spacing between devices, and reduces production costs by allowing for fewer semiconductor light emitting devices per package.
Implementation Method 1
a wavelength conversion layer in the concave portion and surrounding the at least one LED chip, the wavelength conversion layer being surrounded by the sidewalls of the package body and including a wavelength conversion material
Implementation Method 2
a transparent resin layer on the wavelength conversion layer to seal the wavelength conversion layer
Data Source
AI summary
A semiconductor light emitting device includes a package body including a concave portion surrounded by sidewalls, a light emitting diode (LED) chip on a mounting surface of the concave portion, a lead frame in the package body and electrically connected to the LED chip, a wavelength conversion layer in the concave portion and surrounding the LED chip, the wavelength conversion layer being surrounded by the sidewalls of the package body and including a wavelength conversion material, and a transparent resin layer on the wavelength conversion layer, the transparent resin layer having first opposite side surfaces exposed through sides of the package body and spaced apart from each other along a first direction parallel to the mounting surface, and second opposite side surfaces contacting an inner surface of the package body and spaced apart from each other in a second direction parallel to the mounting surface.