LED Package Asymmetric Light-Transmissive Layer Geometry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current LED packages face challenges in achieving high light extraction efficiency, particularly as LEDs shrink in size, leading to issues with optical loss and reduced emission characteristics due to the geometry of light-transmissive layers and coating layers.
Innovation Solution
The proposed LED package incorporates a light-transmissive layer covering the upper surface and side surfaces of the LED, a wavelength conversion layer to change the light wavelength, and a coating layer to reflect light upward, with the light-transmissive layer's side surfaces inclined relative to the LED's surfaces, optimizing the geometry to enhance light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the LED size is reduced, then the device becomes more compact and integration is improved, but light extraction efficiency deteriorates due to geometric constraints of the light-transmissive layer
Solution Approach 1:
The light-transmissive layer is designed with an asymmetric cross-sectional shape where the width at the upper surface is greater than the width at the lower surface. This asymmetric geometry allows the layer to maintain adequate light extraction capability while accommodating smaller LED sizes, as the wider upper portion provides sufficient area for light emission and extraction despite the overall reduced device dimensions.
Solution Approach 2:
The patent transitions from a conventional rectangular light-transmissive layer to one with an inclined side surface, effectively utilizing the vertical dimension to create a trapezoidal cross-section. This dimensional change allows the layer to maintain functional performance in a reduced footprint by optimizing the distribution of material across different heights rather than relying solely on horizontal expansion.
2Ease of manufacture
If the light-transmissive layer has a conventional rectangular shape, then manufacturing is simple, but optical loss increases and emission characteristics are reduced
Solution Approach 1:
The light-transmissive layer employs an asymmetric cross-sectional shape with inclined side surfaces rather than vertical walls. This asymmetric design optimizes light extraction by providing a larger upper surface area for light emission while maintaining structural integrity, thereby reducing optical loss without significantly complicating the manufacturing process.
Solution Approach 2:
The patent modifies the geometric parameters of the light-transmissive layer by introducing an inclination angle to the side surfaces and creating a width ratio between upper and lower surfaces. This parameter change optimizes the optical path and light distribution, reducing total internal reflection and improving emission characteristics while remaining compatible with standard semiconductor manufacturing techniques.
3Loss of energy
If the coating layer is added to reflect light upward, then light extraction efficiency is improved, but device complexity increases
Solution Approach 1:
The coating layer is integrated with the light-transmissive layer to form a unified optical structure. The coating layer is applied directly on the inclined side surfaces and upper surface of the light-transmissive layer, merging the light guiding function with the light reflection function in a single integrated component rather than separate elements, thereby reducing overall package complexity.
Solution Approach 2:
The coating layer serves multiple functions simultaneously: it reflects light upward to improve extraction efficiency, protects the inclined side surfaces of the light-transmissive layer, and maintains the structural integrity of the package. This multi-functionality reduces the need for additional separate components, keeping the device complexity manageable despite the enhanced optical performance.
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 effectively increases light extraction efficiency by preventing optical loss and improving emission characteristics, ensuring efficient light reflection and distribution, even at smaller LED sizes.
Implementation Method 1
a light-transmissive layer covering the upper surface and at least some portions of the side surfaces of the LED, and configured to direct the light emitted from the LED in an upward direction
Implementation Method 2
a coating layer covering side surfaces of the light-transmissive layer, and configured to reflect the light emitted through the light-transmissive layer in the upward direction at an interface with the light-transmissive layer
Implementation Method 3
a wavelength conversion layer disposed on the light-transmissive layer, and configured to change a wavelength of the light emitted through the light-transmissive layer
Data Source
AI summary
A light-emitting diode (LED) package includes: an LED having a polygonal shape in a plan view; a light-transmissive layer directing light from the LED in an upward direction; a wavelength conversion layer changing a wavelength of the light emitted through the light-transmissive layer; and a coating layer covering the light-transmissive layer and reflecting the light emitted through the light-transmissive layer in the upward direction. In a plan view of the light-transmissive layer, a length from a first point corresponding to a vertex of the LED to a second point corresponding to an end of an extension of a diagonal of the LED is greater than or equal to a length from the first point to a third point corresponding to an end of an extension of a side of the LED.