Color Correcting Collimator for Position-Dependent Light Spreading
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Solution Overview
Problem
Existing light sources that emit white light through color mixing often exhibit undesirable color variations in the far field due to 'color over position' (CoP) effects, where the color of the emitted light depends on the emission position, which current technologies struggle to correct effectively.
Innovation Solution
A collimator design featuring position-dependent light spreading elements with varying light beam widening characteristics, arranged around an optical axis, which receives images from an imaging element to improve the mixing of different colors and reduce CoP variations. This design includes microlenses or facets that spread light in multiple planes, ensuring uniform color distribution in the far field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional collimators are used to correct color variation, then color uniformity is improved, but device complexity increases due to specific structural requirements
Solution Approach 1:
The patent applies local quality by providing different light spreading characteristics at different positions around the optical axis. Each light spreading element has characteristics tailored to its specific position, with elements farther from the axis having greater beam widening capability. This position-dependent differentiation corrects color over position variation while maintaining a relatively simple overall collimator structure.
2Stability of the object's composition
If light spreading elements with position-dependent characteristics are used, then color over position variation is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs parameter changes by varying the light beam widening characteristics of spreading elements as a function of their position relative to the optical axis. Elements at different radial distances have different spreading parameters, which compensates for color variation. This approach trades some manufacturing precision requirements for a systematic parameter variation that can be implemented through standardized element designs with position-dependent properties.
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 collimator effectively reduces undesirable color variations in the far field light by spatially separating and equally spreading light beams, preventing any single color from dominating, thus enhancing the uniformity of white light emission from light sources like mid-power LEDs.
Implementation Method 1
The imaging element is configured for one dimensional imaging or two dimensional imaging
Implementation Method 2
The light spreading elements are adapted to spread light striking the light spreading elements
Implementation Method 3
The light spreading elements have different light beam widening characteristics
Implementation Method 4
The light spreading elements are adapted to spread light striking the light spreading elements in a first plane that includes the optical axis
Data Source
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AI summary
A collimator (3) for a color over position light source (2) is provided. The collimator (3) comprises a focal point (F), an optical axis (OA) containing the focal point (F), an imaging element (4) arranged around or on the optical axis (OA) and several light spreading elements (5, 11, 12) arranged around the optical axis (OA) to receive at least one image from the imaging element (4). The light spreading elements (5, 11, 12) have different light beam widening characteristics, the light beam widening characteristics of each light spreading element (5, 11, 12) of said light spreading elements (5, 11, 12) depending on the position of the light spreading element (5, 11, 12) relative to the focal point (F). The light spreading elements (5, 11, 12) are adapted to spread light striking the light spreading elements (5, 11,12) in a first plane (M) including the optical axis (OA). A method for collimating light from a color over position light source (2) is also provided.