Inclined Sidewall Lead Frames for LED Light Intensity
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Solution Overview
Problem
LED packages experience optical loss and reduced light intensity due to the design of their lead frames, which do not effectively reflect light within the cavity.
Innovation Solution
The LED package features lead frames with inclined sidewalls and a bottom frame, formed through injection molding using reflective metals, to create a cavity that enhances light reflection and intensity by structuring the lead frames to direct light towards the center area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional lead frames with vertical sidewalls are used, then the structure is simple and easy to manufacture, but optical loss increases and light intensity decreases
Solution Approach 1:
The lead frame sidewalls are designed with inclined angles rather than vertical configurations, creating curved or angled surfaces that optimize light reflection paths. This curvature principle transforms the light reflection geometry to direct more light toward the center area, thereby increasing light intensity while managing the structural complexity through standardized angular designs.
2Loss of energy
If lead frames without reflective coating are used, then the manufacturing process is simpler, but optical loss increases
Solution Approach 1:
The lead frame is constructed as a composite structure combining a base metal material (providing mechanical strength and electrical conductivity) with a reflective metal plating layer (providing high reflectivity). This composite approach reduces optical loss by enhancing light reflection while managing manufacturing complexity through established electroplating or vapor deposition processes that are routinely applied in electronics manufacturing.
3Illumination intensity
If lead frames with inclined sidewalls and reflective plating are used, then reflectivity and light intensity improve, but thermal resistance may increase
Solution Approach 1:
The reflective metal plating is applied selectively to specific surfaces of the lead frame where light reflection is most beneficial (such as sidewalls and bottom surfaces facing the light emitting device), rather than coating the entire structure. This localized application maintains high light intensity in critical areas while minimizing the thermal mass and thermal resistance impact of the reflective coating, allowing heat to dissipate more efficiently through the base metal 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
This design reduces optical loss, increases light intensity at the center of the cavity, and improves thermal resistance by using reflective metal-plated lead frames with inclined sidewalls, achieving higher reflectivity and improved thermal characteristics.
Implementation Method 1
lead frames with inclined sidewalls and a bottom frame, formed through injection molding using reflective metals, to create a cavity that enhances light reflection and intensity
Implementation Method 2
at least two sidewall frames extending from the bottom frame and inclined with respect to the bottom frame
Data Source
AI summary
Disclosed is a light emitting device package. The light emitting device package includes a package body having a first cavity and a second cavity; a plurality of reflective frames comprising a first reflective frame and a second reflective frame on the first cavity and the second cavity, respectively, and each of the first reflective frame and the second reflective frame comprises a bottom frame and at least two side wall frames extending from the bottom frame; and a light emitting device on the first reflective frame, wherein the first reflective frame and the second reflective frame are electrically separated from each other.