Laser Diode Encapsulation With Floating Cover for Beam Quality
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Solution Overview
Problem
Conventional laser packages with hermetically sealed housings and optical windows are costly and complex to manufacture, and they can affect the optical properties and beam quality of laser diodes, especially those emitting blue and ultraviolet light.
Innovation Solution
An optoelectronic lighting device that uses a mold compound to encapsulate a light emitting semiconductor element, eliminating the need for a hermetically sealed housing, and incorporates a cover element that is transparent and arranged to float on the mold compound, minimizing its impact on the optical properties and beam quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hermetically sealed housing with optical window is used to protect laser diodes from oxygen degradation, then the ageing behavior is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes the hermetically sealed housing structure entirely, extracting only the essential protective function. The semiconductor element is directly encapsulated in mold compound without requiring a complex hermetic housing, optical windows, or sealing mechanisms, thus simplifying the device while maintaining protection from environmental degradation.
Solution Approach 2:
The patent changes the protective parameter from hermetic sealing to optical transparency. By selecting mold compound materials with high transparency to blue and ultraviolet light, the protection mechanism shifts from physical isolation to optical compatibility, eliminating the need for complex hermetic structures while maintaining element protection.
2Manufacturing precision
If an optical window is added to the hermetically sealed housing to maintain beam quality, then the optical properties are preserved, but the device complexity and cost increase
Solution Approach 1:
The patent merges the protective encapsulation function with the optical transmission function into a single mold compound material. The mold compound simultaneously protects the semiconductor element from environmental degradation and maintains optical properties for beam quality, eliminating the separate optical window component and reducing device complexity.
Solution Approach 2:
The mold compound serves multiple functions: it provides mechanical support, environmental protection, electrical insulation, and optical transmission. This multi-functional material replaces the traditional hermetic housing with optical window, simplifying the overall device structure while maintaining both protective and optical functions.
3Ease of manufacture
If the semiconductor element is directly encapsulated in mold compound, then the manufacturing process is simplified, but the surface unevenness negatively affects optical properties
Solution Approach 1:
The patent introduces a cover element as an intermediary between the mold compound and the external environment. This cover element provides a smooth, uniform surface for optimal light extraction while the mold compound maintains direct contact with the semiconductor element for simplified encapsulation. The cover element acts as a mediator that resolves the surface unevenness issue without complicating the manufacturing process.
4Manufacturing precision
If a cover element is added to provide a smooth surface, then the beam quality is improved, but the device complexity increases
Solution Approach 1:
The cover element is implemented as a thin, simple protective layer that provides the necessary smooth surface for optimal optical performance. This thin-film approach maintains beam quality while minimizing the addition of structural complexity, as the cover element can be integrated into the existing encapsulation process without requiring complex assembly steps.
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 solution improves the aging behavior of the semiconductor element without the need for a hermetically sealed housing, allowing for a more flexible design, potential miniaturization, simpler manufacturing processes, and reduced costs, while maintaining the optical properties and beam quality of the light emitted.
Implementation Method 1
a mold compound which is substantially transparent to the light emitted by the semiconductor element and which encapsulates the light emitting semiconductor element on the carrier
Implementation Method 2
a cover element which is substantially transparent to the light emitted by the semiconductor element is arranged flying or floating on the mold compound
Data Source
AI summary
The invention relates to an optoelectronic lighting device comprising a carrier, at least one light emitting semiconductor element which is arranged on a top surface of the carrier and is configured to emit light with a wavelength smaller than 550 nm, a mold compound which is substantially transparent to the light emitted by the semiconductor element and encapsulates the light emitting semiconductor element on the carrier, a frame which is arranged on the top surface of the carrier and projects beyond the light emitting semiconductor element in a direction perpendicular to the top surface of the carrier, and which delimits the mold compound in at least one spatial direction, and a cover element which is substantially transparent to the light emitted by the semiconductor element and which is arranged floating on the mold compound as seen in an emission direction of the optoelectronic lighting device.