Light Emitting Device Metal Member Sealing Structure
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Solution Overview
Problem
Modern light emitting devices face challenges in achieving better light extraction efficiency, smaller size, and thinner profiles while maintaining strong adhesion between metal and sealing members, and ensuring overall performance aspects such as heat dispersion and service life.
Innovation Solution
A light emitting device design featuring a metal member with a concave element placement portion and a flat portion surrounded by a covering member, where the translucent member covers the metal member and covering member, with a softer translucent member and a harder covering member to enhance sealing and light extraction efficiency, and a manufacturing method that includes forming a covering member with higher viscosity to secure the metal member in molds during molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing member is made thicker to ensure strength and adhesion, then the adhesion between metal members and sealing member is improved, but the device thickness increases and light extraction efficiency decreases
Solution Approach 1:
The sealing member is divided into two distinct parts: a hard covering member that provides structural strength and adhesion to the metal member, and a soft translucent member that provides sealing and light extraction. This segmentation allows each part to be optimized for its specific function without compromising the other, resolving the contradiction between adhesion strength and device thickness.
Solution Approach 2:
Different regions of the sealing structure are assigned different material properties: the covering member uses a hard material with high adhesion to the metal member, while the translucent member uses a soft material with high light transmission. This local differentiation of material qualities allows the structure to simultaneously achieve strong adhesion and thin profile with high light extraction efficiency.
2Strength
If the sealing member is made thicker to ensure strength, then the strength of the sealing member is improved, but the light extraction efficiency to the upper face side decreases
Solution Approach 1:
The sealing member is segmented into a hard covering member for structural strength and a soft translucent member for light extraction. This segmentation allows the light to pass through the thin translucent member with minimal attenuation while the hard covering member provides the necessary structural support, resolving the contradiction between strength and light extraction efficiency.
Solution Approach 2:
The soft translucent member acts as an intermediary between the hard covering member and the external environment, providing a thin optical path for light extraction while the hard covering member provides structural support. This intermediary structure allows both strength and high light extraction efficiency to be achieved simultaneously.
3Volume of stationary object
If the contact surface area between metal member and sealing member is reduced to decrease device size, then the device size is reduced, but the adhesion and sealing reliability decreases
Solution Approach 1:
The covering member uses a hard material with high adhesion properties that concentrates bonding strength at the metal member interface. This local quality enhancement allows the sealing structure to maintain high reliability with reduced contact surface area, enabling smaller device size without compromising sealing reliability.
4Reliability
If a hard covering member is added to improve adhesion, then the adhesion between metal member and sealing member is improved, but the device complexity increases
Solution Approach 1:
The covering member and translucent member are combined into a single integrated sealing member structure. This merging reduces manufacturing steps and assembly complexity compared to separate components, while still providing the adhesion benefits of the hard covering member and the light extraction benefits of the soft translucent member.
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2~3
AI summary
A light emitting device has: a light emitting element; a metal member having a first face on which the light emitting element is mounted, and a second face that is on the opposite side from the first face; and a translucent member that seals part of the metal member and the light emitting element, the metal member has an element placement portion on which the light emitting element is placed, and a flat portion disposed around the element placement portion, a covering member is disposed on the second face side of the flat portion, and the top and side faces of the covering member are covered by the translucent member.