Light-Emitting Device Lateral Light Extraction via Guiding Members
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Solution Overview
Problem
Light-emitting devices face inefficiencies in guiding lateral light emission to the upper surface, resulting in reduced luminance.
Innovation Solution
A light-emitting device structure incorporating a first and second light-transmissive member with specific surface area ratios and a light-guiding member configuration to enhance light extraction, where the first light-transmissive member contains a wavelength conversion member and the second light-transmissive member has a smaller upper surface area, allowing for efficient light guidance and reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the area of the light-extracting surface is reduced to increase light intensity, then luminance is improved, but light emitted laterally from the light-emitting element cannot be efficiently guided to the upper surface
Solution Approach 1:
The patent introduces light-guiding members that extend laterally from the light-emitting element to redirect sideways-emitted light upward toward the light-extracting surface. This adds a dimensional component to light guidance, capturing light that would otherwise be lost laterally and redirecting it to contribute to luminance.
Solution Approach 2:
The light-guiding members act as intermediary structures between the light-emitting element and the light-extracting surface. These members receive light emitted laterally from the light-emitting element and guide it to the upper surface, thereby improving overall light extraction efficiency without increasing the light-extracting surface area.
2Ease of operation
If a diffusion resin layer is used to distribute light, then light distribution is improved, but the intensity of light is reduced
Solution Approach 1:
The patent applies different functional properties to different regions: the light-guiding members are designed with specific optical properties to capture and redirect lateral light, while the light-extracting surface maintains high intensity. This local differentiation allows simultaneous optimization of both light distribution and intensity without uniform diffusion throughout the entire structure.
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
The configuration increases luminance by effectively guiding and reflecting light, allowing for higher light extraction efficiency and irradiation to distant locations.
Implementation Method 1
the first light-transmissive member containing a wavelength conversion member
Implementation Method 2
a light-guiding member disposed over the at least one lateral surface of the light-emitting element
Implementation Method 3
the first light-transmissive member... including: an upper surface, at least one lateral surface, and a lower surface
Data Source
AI summary
A light-emitting device includes a light-emitting element; a first light-transmissive member bonded to the light-emitting element, containing a wavelength conversion member, and including a lower surface having an area larger than an upper surface of the light-emitting element; a second light-transmissive member bonded to an upper surface of the first light-transmissive member, including a lower surface having an area larger than the upper surface of the first light-transmissive member and having a periphery located outward of the upper surface of the first light-transmissive member, and an upper surface having an area smaller than the upper surface of the light-emitting element; a first light-guiding member over a lateral surface of the light-emitting element and the periphery of the lower surface of the first light-transmissive member; and a second light-guiding member over a lateral surface of the first light-transmissive member and the periphery of the lower surface of the second light-transmissive member.