LED Package Lens Support Dam and Same-Side Electrodes
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Solution Overview
Problem
Existing light emitting diode (LED) packages face issues with molded plastic lenses degrading over time and absorbing electromagnetic radiation, and wire bonding defects, while glass lenses are more expensive and require additional manufacturing steps.
Innovation Solution
A light emitting diode (LED) package design featuring a lens support dam made from non-degrading materials like glass or quartz, with same-side electrodes allowing chip-on-board assembly without wire bonding, and a short circuit die to electrically connect the LEDs, reducing the need for additional manufacturing steps and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a molded plastic lens is used to cover and protect the LED die, then the manufacturing cost is reduced and the manufacturing process is simplified, but the lens degrades with time and absorbs electromagnetic radiation
Solution Approach 1:
The lens is divided into two separate components: a molded plastic lenslet integrated with the LED die for light emission, and a separate glass lens for protection. This segmentation allows each component to be optimized independently - the plastic lenslet maintains manufacturing simplicity while the glass lens provides durability and radiation resistance.
Solution Approach 2:
A reflective layer is introduced as an intermediary between the LED die and the glass lens. This reflective layer redirects light that would otherwise be absorbed by the glass lens, maintaining optical efficiency while allowing the use of durable glass material for the protective lens.
2Reliability
If a glass lens is used to protect the LED die, then the lens durability and resistance to degradation is improved, but additional manufacturing elements and steps are required
Solution Approach 1:
The molded plastic lenslet is merged directly with the LED die in a single molding step, creating an integrated assembly. This eliminates the need for separate mounting of the protective lens, reducing manufacturing complexity while still allowing the use of a separate durable glass lens for protection.
Solution Approach 2:
The protective glass lens is positioned and secured to the LED package before final encapsulation with the reflective layer and sealing adhesive. This preliminary positioning ensures proper alignment and simplifies the overall manufacturing process by establishing the lens configuration early in the assembly sequence.
3Reliability
If wire bonding is used to connect the LED die to the package substrate, then electrical connection is achieved, but defects occur and the connection degrades with time
Solution Approach 1:
The wire bonding process is completely removed from the manufacturing process. Instead, the LED die is directly mounted onto the package substrate with electrical contacts, eliminating the intermediate wire bonding step that causes defects and degradation over time.
Solution Approach 2:
The mechanical wire bonding system is replaced with a direct electrical contact system where the LED die is mounted onto the substrate. This substitution eliminates the mechanical stress and potential connection failures associated with wire bonding while simplifying the manufacturing process.
4Reliability
If same side electrodes are used to enable chip-on-board mounting without wire bonding, then the footprint is reduced and reliability is improved, but additional manufacturing steps are required
Solution Approach 1:
The package substrate is designed with multiple functional layers that serve both electrical connection and mechanical support functions. The conductive layers and insulating layers are integrated into a single substrate structure, allowing the same component to perform multiple functions and reducing the overall number of manufacturing steps.
Solution Approach 2:
The electrical conductivity parameters of the substrate are modified by introducing conductive layers at specific positions. This allows the substrate to function as both a mechanical support structure and an electrical connection pathway, enabling direct mounting of the LED die without wire bonding while maintaining manufacturing efficiency.
Data Source
AI summary
A light emitting diode (LED) package includes a main vertical LED (VLED) die; a short circuit VLED die; a lens support dam; a transparent lens attached to the lens support dam; a first electrode in electrical communication with a first semiconductor layer of the main VLED die and a second electrode in electrical communication with a second semiconductor layer of the main VLED die.