Light Emitting Device Recess Design for Brightness and Bonding
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Solution Overview
Problem
Conventional light emitting devices face challenges in enhancing front illumination intensity while maintaining directivity, due to limitations in the design of reflective surfaces and bonding with light-transmitting resins, which affect brightness and bonding strength.
Innovation Solution
A light emitting device with a substrate featuring two recesses, where the first recess has a larger opening area than the second, and a conductor layer configuration that includes frame portions and strip-like electrodes, along with a lens system for enhanced light refraction, to improve light intensity and directivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the depth of the recess is increased to increase the reflective surface area, then the area of the side surface is increased, but the depth can be increased only within a limited range due to the nested structure
Solution Approach 1:
The invention divides the single nested recess structure into two separate recesses: a first recess for the light emitting element and a second recess for the wire. This segmentation allows the first recess to have a greater depth without being constrained by the nested structure limitation, thereby increasing the reflective surface area while maintaining manufacturing feasibility.
2Illumination intensity
If the inner lead portion is made narrow to reduce light shielding, then the brightness is improved, but the bonding strength with the light-transmitting resin deteriorates
Solution Approach 1:
The invention transitions from a two-dimensional planar bonding interface to a three-dimensional bonded structure by forming protrusions on the inner lead portion that extend into the light-transmitting resin. This dimensional change increases the bonding surface area and mechanical interlocking without increasing the planar width of the inner lead portion, thereby maintaining brightness while improving bonding strength.
3Ease of manufacture
If the die pad portion dimension is increased to secure bonding space, then the ease of bonding is improved, but the inner lead portion width must be increased which causes light shielding
Solution Approach 1:
The invention segments the bonding structure by adding protrusions on the inner lead portion that provide additional bonding surface area. This allows the die pad portion to maintain its compact size for adequate bonding space while the inner lead portion width remains narrow to minimize light shielding, as the protrusions provide the necessary bonding interface without requiring increased planar dimensions.
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 solution enhances front illumination intensity and maintains directivity by optimizing the reflective surface area and conductor layer design, while preventing light shielding and ensuring strong bonding with the light-transmitting resin.
Implementation Method 1
The side surface 911b of the recess 911 is a reflective surface which reflects the light emitted from the light emitting element 94
Implementation Method 2
The recess 585 is filled with light-transmitting resin 592. The light emitted from the LED element 581 is reflected at the reflective surface 584 of the recess 585, passes through the light-transmitting resin 592, and is then emitted to the outside of the case 582
Data Source
AI summary
A light emitting device includes a light emitting element, a wire connected to the light emitting element, and a substrate supporting the light emitting element. The substrate is formed with a first recess and a second recess that are open in a common surface of the substrate. The first recess includes a first bottom surface and a first side surface connected to the first bottom surface, and the light emitting element is disposed on the first bottom surface. The second recess includes a second bottom surface and a second side surface connected to the second bottom surface, and the wire is bonded to the second bottom surface. Both of the first side surface and the second side surface reach the common surface. The first side surface is connected to both of the second bottom surface and the second side surface. The opening area of the first recess is larger than the opening area of the second recess.