Light Emitting Device Resin Package Wall Sulfuration Prevention
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Solution Overview
Problem
Silver and silver alloy lead frames and wires in light emitting devices are prone to sulfuration, leading to light absorption and inefficient light reflection due to gaps between resin and metal components, which existing sealing methods fail to effectively prevent.
Innovation Solution
A light emitting device design with a resin package that includes a wall portion between lead frames and light emitting elements, preventing gaps and using a translucent resin with zinc additives to suppress sulfuration, along with a wire bonding configuration that minimizes light absorption and enhances light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If silver or silver alloy is used as lead frame or wire material, then light reflection efficiency is improved, but sulfuration occurs causing light absorption
Solution Approach 1:
A resin layer is introduced as an intermediary substance between the silver lead frame/wire and the external environment (air, moisture). This resin layer acts as a barrier that prevents sulfuration while allowing the silver to maintain its light reflection function. The resin fills gaps and creates a sealed environment around the metal components.
Solution Approach 2:
The resin package creates an inert protective environment around the silver components, isolating them from reactive substances in the air (oxygen, moisture) that cause sulfuration. This effectively creates a localized inert atmosphere that preserves the metal's reflective properties over time.
2Reliability
If resin is used to seal light emitting element, then sulfuration is suppressed, but gaps between resin and metal components allow sulfuration to occur
Solution Approach 1:
The resin is applied as a flexible sealing layer that conforms to the contours of the metal components (lead frame, wire). This thin film-like resin structure能够有效ly seals gaps and interfaces between different components, preventing air and moisture penetration while maintaining flexibility to accommodate component variations.
Solution Approach 2:
The resin sealing is integrated directly with the metal components, merging the protective function with the structural assembly. The resin is applied to fill gaps between the lead frame, wire, and housing, creating a unified sealed structure rather than separate sealing components.
3Volume of moving object
If package size is reduced, then device miniaturization is achieved, but sealing effectiveness may be compromised
Solution Approach 1:
The resin sealing layer is designed as a thin film structure that provides effective sealing without adding significant thickness to the device. This flexible thin-film approach allows miniaturization while maintaining sealing integrity.
Solution Approach 2:
The package utilizes a composite structure combining resin sealing material with metal components, creating a compact integrated assembly. The resin-metal composite structure achieves both miniaturization and effective sealing by eliminating separate sealing components and integrating functions.
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 design effectively prevents sulfuration of silver components, ensuring high-intensity light emission while reducing device size and thickness, and allows for efficient light extraction and improved durability.
Implementation Method 1
using a translucent resin with zinc additives to suppress sulfuration
Implementation Method 2
efficiently reflect and extract light
Data Source
AI summary
A light emitting device includes a plurality of light emitting elements, a plurality of lead frames, and a package. The light emitting elements are mounted on the lead frames. The package is made of resin. The package has an opening. A part of the lead frames is embedded in an inner portion of the package and another part of the lead frames is exposed on a bottom surface of the opening. A resin bottom surface on which the resin is exposed is provided on the bottom surface of the opening of the package. The package includes a wall portion projecting from the bottom surface of the opening between the light emitting elements in the opening. The light emitting elements are connected by wire that straddles the wall portion.