Spherical Lens Aplanatic Imaging for Remote Phosphor Beam Control
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Solution Overview
Problem
Conventional light-emitting devices using remote phosphor luminous elements face challenges in designing efficient optics to tailor light distribution for applications requiring narrower beam patterns or steep cutoffs, often resulting in unwanted losses and reduced efficiency due to aberrations and internal reflection losses.
Innovation Solution
The design incorporates lenses with spherical refractive exit surfaces and reflective sidewalls to achieve aplanatic imaging, reducing primary aberrations and optimizing light distribution, while reflective features like conical or equiangular spiral sidewalls redirect light to enhance efficiency and control beam patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional optics are used to tailor light distribution for narrower beam patterns, then beam control is improved, but optical efficiency deteriorates due to losses from blocking and redirection
Solution Approach 1:
The patent employs a spherical lens with a specific radius of curvature to achieve aplanatic imaging of the remote phosphor luminous element. This curved optical surface redirects light rays to form desired beam patterns while maintaining high optical efficiency by avoiding blocking losses associated with conventional optics.
2Shape
If conventional optics are used to achieve steep cutoff at beam edges, then beam pattern control is improved, but optical efficiency deteriorates due to unwanted losses
Solution Approach 1:
The spherical lens geometry with precisely controlled radius enables steep cutoff at beam edges through aplanatic imaging, achieving sharp beam patterns without the efficiency penalties of conventional blocking or redirecting optics.
3Device complexity
If phosphor is positioned close to LED die for compact design, then device complexity is reduced, but color uniformity deteriorates due to high temperature exposure
Solution Approach 1:
The patent extracts the phosphor from immediate proximity to the LED die and positions it as a remote phosphor luminous element at a controlled distance. This separation reduces thermal exposure and improves color uniformity while maintaining design simplicity through the spherical lens integration.
4Reliability
If remote phosphor is used to improve color stability, then reliability is improved, but manufacturing complexity increases due to positioning requirements
Solution Approach 1:
The spherical lens with its geometric properties provides inherent alignment tolerances that simplify the positioning of the remote phosphor. The aplanatic imaging condition achieved through the spherical geometry maintains color stability while accommodating practical manufacturing variations.
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 high-efficiency light-emitting devices with well-controlled angular distribution and improved optical efficiency, capable of producing desired beam patterns with reduced losses, suitable for various general lighting applications.
Implementation Method 1
lens of refractive index n with a convex spherical exit surface... that portion of the edge of the emitting surface is aplanatically imaged by the spherical exit surface
Implementation Method 2
positioned such that at least a portion of an edge of the emitting surface lies approximately on a notional sphere... whereby that portion of the edge of the emitting surface is substantially aplanatically imaged by the spherical exit surface
Implementation Method 3
reflective features like conical or equiangular spiral sidewalls redirect light to enhance efficiency and control beam patterns
Data Source
AI summary
A light-emitting device includes a lens of refractive index n having a spherical exit surface of radius R and a luminous element positioned such that at least a portion of an edge of an emitting surface of the luminous element lies on a sphere of radius R/n opposite the exit surface, whereby that portion of the edge of the emitting surface is aplanatically imaged by the spherical exit surface. The light-emitting device may further include one or more reflective sidewalls arranged to reflect a fraction of light emitted from the luminous element before it is refracted by the exit surface. A luminaire incorporating a housing and a light-emitting device of this type is also provided, which may include one or more additional optical elements such as reflectors or lenses to further direct and shape light from the light-emitting device.