Tilted Lens Array for Uniform LED Spot Lighting
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Solution Overview
Problem
Medium power LEDs often result in non-uniform color distribution when used in spot lighting applications due to their divergent light emission, which is exacerbated by the difficulty in achieving a collimated and uniformly colored beam, even with collimation and Koehler lens designs.
Innovation Solution
An optical beam shaping arrangement comprising a collimator and an optical plate with a two-dimensional array of lenses on both sides, where the lenses on the output side are tilted to adjust beam shaping properties, providing a diffusing function and allowing for a circular beam shape in the far field, despite a hexagonal grid pattern, thereby controlling angular intensity distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If medium power LEDs are used for spot lighting, then light output is improved, but color uniformity deteriorates due to divergent emission and non-uniform color distribution
Solution Approach 1:
The optical plate segments the light path into multiple controlled regions using a two-dimensional array of lenses, each lens handling a specific angular range. This segmentation allows independent control of color mixing for different emission angles, resolving the color uniformity issue while maintaining high light output from medium power LEDs
Solution Approach 2:
The invention changes the orientation parameter of lenses by tilting them at specific angles relative to the normal of the optical plate. This parameter change enables precise control over the angular distribution of light, transforming the divergent emission pattern into a controlled collimated beam with uniform color distribution across the spot
2Speed
If collimation optics are added to medium power LEDs, then beam directionality is improved, but color distribution effects worsen due to non-uniform color over the LED surface
Solution Approach 1:
Different regions of the optical plate are assigned different lens orientations and focal properties, creating local quality variations that compensate for the non-uniform color distribution of the LED. Each local region processes light from a specific angular range with tailored optical characteristics, ensuring uniform overall color distribution while maintaining beam directionality
3Stability of the object's composition
If Koehler lens design is used for color mixing, then color uniformity is improved, but beam shape control deteriorates making it difficult to achieve desired intensity characteristics
Solution Approach 1:
The invention introduces dynamic control over beam shaping by varying the tilt angles of different lenses in the array. This allows the optical system to adaptively control the angular intensity distribution and beam shape characteristics while maintaining the color mixing function, enabling independent optimization of both color uniformity and beam shape
4Illumination intensity
If a two dimensional array of lenses is used for beam shaping, then angular intensity distribution is improved, but device complexity increases
Solution Approach 1:
The two-dimensional lens array is designed to perform multiple functions simultaneously: collimation, color mixing, and angular intensity distribution control. By integrating these functions into a single optical plate structure, the invention achieves superior beam control without proportionally increasing device complexity, as the same lens elements provide multiple optical effects
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 solution effectively broadens the beam and ensures a circular light intensity distribution in the far field, improving color uniformity and beam control, allowing for a more efficient and uniform light output from medium power LEDs in spot lighting applications.
Implementation Method 1
a collimator for receiving light from an optical source, and providing a more collimated output
Implementation Method 2
the lenses on the output side are tilted with respect to the general plane of the optical plate... The tilt provides an inclination of the optical axis of the lens with respect to the normal direction to the general plane of the optical plate. This tilt provides a diffusing and therefore beam broadening function
Implementation Method 3
The function of each Koehler lens pair is to re-distribute the light entering the first side of the substrate to remove angular information of the original beam spot
Data Source
AI summary
In various embodiments described herein, an optical beam shaping arrangement is disclosed. In one example, the optical beam shaping arrangement comprises a collimator for receiving light from an optical source, and providing a more collimated output, and an optical plate for receiving the more collimated output, the optical plate comprises a two dimensional array of lenses on an input side and a corresponding two dimensional array of lenses on the opposite output side. In at least one embodiment, the lenses on the input side each have a focal point at a corresponding lens on the output side, and the lenses on the output side each have a focal point at a corresponding lens on the input side, and at least some of the lenses on the output side are tilted with respect to the general plane of the optical plate.