Planar LED Encapsulant for Omnidirectional Light Recycling
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Solution Overview
Problem
Conventional LED packages face inefficiencies due to heat retention and limited emission patterns, often requiring larger sizes and using toxic materials, while existing solutions like CFLs pose environmental risks and inefficiencies.
Innovation Solution
The development of compact LED packages with planar surfaces that utilize total internal reflection (TIR) to recycle light within the encapsulant, featuring a blanket conversion material layer covering the LEDs and submount, allowing for omnidirectional emission and reduced absorption, thereby enhancing efficiency and emission profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional LED packages use hemispheric encapsulants or lenses, then light emission is achieved, but device size increases and emission pattern is limited
Solution Approach 1:
The patent employs a planar encapsulant with flat surfaces instead of traditional hemispheric or lens-shaped encapsulants. This planar configuration enables total internal reflection (TIR) at the encapsulant surfaces, recycling light that would otherwise be lost and achieving omnidirectional emission patterns without requiring larger device dimensions.
Solution Approach 2:
The invention transitions from conventional hemispheric encapsulants to a planar encapsulant structure with multiple flat surfaces. This dimensional change enables light to be reflected and redirected through TIR at various angles, creating omnidirectional emission patterns while maintaining a compact footprint.
2Illumination intensity
If conventional LED packages use reflective cups or reflectors, then light direction is improved, but heat extraction becomes difficult and efficiency decreases
Solution Approach 1:
The patent removes the reflective cup or reflector components from the LED package structure. Instead of using separate reflective elements to direct light, the invention utilizes the planar encapsulant surfaces themselves to achieve TIR and light recycling, thereby eliminating the heat retention problems associated with metal reflectors and improving thermal management.
Solution Approach 2:
The planar encapsulant serves multiple functions simultaneously: it provides structural protection, enables TIR for light recycling, and facilitates heat dissipation by eliminating metal reflector components. This multi-functionality resolves the contradiction between light direction and heat extraction.
3Adaptability or versatility
If conventional LED packages use larger sizes, then emission pattern coverage is improved, but device footprint increases
Solution Approach 1:
The planar encapsulant structure enables light to be reflected and redirected multiple times within the encapsulant itself through TIR. This self-service mechanism allows the light to explore different paths and achieve omnidirectional emission patterns without requiring a larger device footprint, as the light recycling occurs within the existing compact structure.
4Strength
If conventional LED packages use metal reflectors, then mechanical protection is provided, but optical losses occur due to absorption
Solution Approach 1:
The patent converts the harmful effect of light absorption by metal reflectors into a beneficial TIR mechanism at the planar encapsulant surfaces. The encapsulant materials are selected to have high optical transparency and low absorption, transforming the optical loss problem into an efficient light recycling mechanism that improves overall package efficiency.
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 approach results in more efficient light emission with a broader emission profile, reduced heat retention, and a more compact design, while minimizing the use of toxic materials, making the LED packages cost-effective and environmentally friendly.
Implementation Method 1
The packages according to the present invention can be arranged to capitalize on the total internal reflection (TIR) of light within the package
Implementation Method 2
The conversion material layer can be of the type that converts light from the LED to another color or wavelength of light
Implementation Method 3
LED packages with encapsulants having planar surfaces that refract and/or reflect light within the package encapsulant
Data Source
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AI summary
LED packages are disclosed that are compact and efficiently emit light, and can comprise encapsulants with planar surfaces that refract and/or reflect light within the package encapsulant. The packages can also comprise a submount with one or more LEDs, and a blanket conversion material layer on the one or more LEDs and the submount. The encapsulant can be on the submount, over the LEDs, and light reflected within the encapsulant will reach the conversion material, where it will be absorbed and emitted omnidirectionally. This allows for reflected light to now escape from the encapsulant. This allows for efficient emission and a broader emission profile, for example when compared to conventional packages with hemispheric encapsulants or lenses. In certain embodiments, the LED package provides a higher chip area to LED package area ratio. By using an encapsulant with planar surfaces, the LED package can provide unique dimensional relationships between the various features and the LED package ratios, enabling more flexibility in using the packages in different applications.