Stepped Lead Frame Light Emitting Device Package
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Solution Overview
Problem
Existing light emitting device packages face challenges in improving injection molding stiffness, coupling force, and light extraction efficiency, particularly in the spaced spaces between lead frames, which affects productivity and reliability.
Innovation Solution
The light emitting device package incorporates stepped portions and edge portions on the lead frames to enhance injection molding, stiffness, and coupling force, while also improving light extraction efficiency by maintaining a uniform interval between inner side surfaces and the light emitting device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the spaced space between lead frames is reduced to improve packaging density, then the packaging efficiency is improved, but the injection molding quality deteriorates
Solution Approach 1:
The lead frame is segmented into multiple sections with different height levels (first stepped portion, second stepped portion, third stepped portion) to create varied spacing zones. This segmentation allows the mold cavity to access different regions of the spaced space through corresponding recesses at different depths, enabling complete filling of the molding material while maintaining compact packaging dimensions.
Solution Approach 2:
The invention introduces vertical dimensionality through stepped portions at different height levels. Instead of uniform horizontal spacing, the lead frame creates a three-dimensional spaced space with varying depths. The mold cavity corresponds to these different height levels with recesses at first, second, and third levels, transforming a two-dimensional spacing problem into a three-dimensional solution that improves both packaging density and injection molding quality.
2Device complexity
If the lead frame structure is simplified to reduce manufacturing complexity, then the manufacturing cost is reduced, but the stiffness at exposed edges deteriorates
Solution Approach 1:
The lead frame incorporates localized stepped portions at specific exposed edges rather than uniformly complicating the entire structure. The first stepped portion, second stepped portion, and third stepped portion are strategically positioned at edges requiring enhanced stiffness. This local quality approach reinforces only the necessary areas while keeping the rest of the lead frame structure simple and easy to manufacture.
3Strength
If the coupling area between lead frame and body is increased to improve coupling force, then the coupling strength is improved, but the overall device size increases
Solution Approach 1:
The invention utilizes vertical dimensionality through stepped portions at different height levels to increase coupling area without expanding horizontal device dimensions. The first stepped portion, second stepped portion, and third stepped portion create multiple coupling interfaces at different elevations. The mold cavity corresponds with recesses at these different height levels, enabling the coupling surface to extend vertically rather than horizontally, thereby improving coupling force while maintaining compact device size.
Data Source
AI summary
A light emitting device package of an embodiment including a first lead frame; a light emitting device mounted on the first lead frame; a second lead frame spaced apart from the first lead frame in a first direction; a protective device mounted on the second lead frame; and a body coupled to the first and second lead frames, wherein the first lead frame includes a first stepped portion disposed along an edge of a lower surface thereof, and the second lead frame includes a third stepped portion disposed along an edge of a lower surface thereof, a mounting region of the protective device which is not overlapped in a vertical direction and spaced apart from the third stepped portion, and a second wire recess portion which is partially overlapped with the third stepped portion in the vertical direction.