Light Emitting Device with Segmented Insulation for Chromaticity Stability
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Solution Overview
Problem
Existing light emitting devices face issues with unstable light quality and chromaticity due to the viscosity of sealing resin and peripheral temperature affecting the distribution of fluorescent materials, leading to variations in light emission and color tone.
Innovation Solution
A light emitting device design featuring a first lead with a groove or recessed portion to retain a wavelength conversion portion, where the wavelength conversion material is strategically positioned to minimize exposure to the insulating member, allowing efficient heat dissipation and optimized light extraction, with a lens portion covering the wavelength conversion material to enhance light distribution and reduce color deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a sealing resin is used to cover the light emitting element and wire, then the device is enabled to emit white light by inclusion of a fluorescent material, but the viscosity of the sealing resin and peripheral temperature affect the distribution of fluorescent materials, leading to unstable light quality and chromaticity
Solution Approach 1:
The patent divides the sealing structure into two distinct parts: a sealing resin portion and an insulating member portion. This segmentation allows the fluorescent material to be contained specifically in the sealing resin portion, separating the light emission function from the insulation function. By doing so, the distribution of fluorescent materials is stabilized because they are confined to a controlled region rather than being affected by the entire sealing resin volume, thus improving chromaticity stability while maintaining light quality.
Solution Approach 2:
The patent applies local quality by creating a specific region (the sealing resin portion) with concentrated fluorescent material, while the insulating member portion remains free of fluorescent material. This localized approach ensures that the light emission properties are optimized in the sealing resin portion without being compromised by temperature and viscosity variations in the larger insulating member, thereby stabilizing chromaticity and light quality.
2Ease of manufacture
If an insulating substrate is used to mount the light emitting element, then the device can be assembled, but the insulating substrate exhibits high thermal resistance, deteriorating heat dissipation performance
Solution Approach 1:
The patent extracts the insulation function from the sealing resin and places it in a dedicated insulating member. This allows the sealing resin to focus on light emission and sealing functions, while the insulating member handles electrical insulation. The insulating member is designed with thermal conductivity considerations, and the groove structure in the lead frame enables direct thermal contact between the light emitting element and the lead frame, bypassing the insulating member's thermal resistance and improving overall heat dissipation efficiency.
3Reliability
If the insulating member covers the entire lower surface of the lead, then electrical insulation is provided, but heat dissipation is impeded and light extraction efficiency is reduced
Solution Approach 1:
The patent segments the insulating member's coverage area, providing insulation only where electrically necessary (around the wire and light emitting element) while leaving the lower surface of the lead frame exposed in regions where heat dissipation is critical. This selective insulation approach maintains electrical reliability while optimizing thermal performance.
Solution Approach 2:
The patent applies local quality by varying the insulation coverage: the insulating member covers areas requiring electrical isolation but leaves specific regions of the lead frame's lower surface exposed. This creates localized zones of different thermal and electrical properties, optimizing both insulation reliability and heat dissipation efficiency in their respective regions.
4Illumination intensity
If the fluorescent material is distributed throughout the entire sealing resin, then white light emission is achieved, but variations in light emission and color tone occur due to temperature and viscosity effects
Solution Approach 1:
The patent segments the fluorescent material distribution by confining it to the sealing resin portion only, separating it from the insulating member portion. This creates a controlled, localized region for fluorescent material placement, reducing the overall volume affected by temperature and viscosity variations. As a result, the fluorescent material distribution becomes more stable, leading to more uniform light emission and consistent color tone across the device.
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 achieves superior light quality and high light emission efficiency by stabilizing light distribution and chromaticity, reducing variations in light emission and color tone, and allowing for efficient heat dissipation.
Implementation Method 1
a wavelength conversion portion configured to cover the light emitting element
Implementation Method 2
a lens portion configured to cover the wavelength conversion portion
Implementation Method 3
a lead frame configured as a package exhibiting superior heat dissipating performance
Data Source
AI summary
A light emitting device includes a first lead, a second lead, an insulating member, a diffusing agent-containing portion, a wavelength conversion portion and a lens portion. The insulating member is configured to fix the first lead and the second lead. A thickness of the insulating member is equal to the thickness of the first and second leads. A groove or a recessed portion is provided to retain the wavelength conversion portion in a specific region formed in the first lead. A second groove portion or recessed portion is formed in a first lead inner side of the groove portion or the recessed portion, which is filled with the diffusing agent-containing portion.