Ring lighting
First Claim
1. An illuminator comprisinga plurality of light sources mounted in a ring configuration, and an optical system spaced from the plurality of light sources for directing light from the light sources onto a target plane, the optical system including an annular lens mounted to mix light from all of the plurality of light sources and uniformly illuminate the target area, and the properties of the optical system and the spatial arrangement of the optical system with respect to the plurality of light sources is such that the light emitted by the plurality of light sources is mixed tangentially, and radial spread of the light is controlled, to uniformly illuminate the target plane over an area at least equal to that encompassed by the ring of light sources and the illumination extending uniformly from a center to a periphery of the target plane.
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Accused Products
Abstract
An illuminator has a printed circuit board supporting a ring of light emitting diodes (LEDs). An annular Fresnel lens and the board are both mounted in a housing having a central though-hole for a camera field of view. The lens mixes light from the LEDs in the tangential direction and it also controls spread in the radial direction so there is uniform illumination over a target plane. Any individual point on the target plane receives illumination from over 25% of the light sources. The illuminator is thus particularly effective, compact, and suitable for a wide range of industrial applications. Choice of lens and the spatial arrangement allows versatility. The illuminator design is easily scaleable by changing the size and spacing between the light sources.
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Citations
28 Claims
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1. An illuminator comprising
a plurality of light sources mounted in a ring configuration, and an optical system spaced from the plurality of light sources for directing light from the light sources onto a target plane, the optical system including an annular lens mounted to mix light from all of the plurality of light sources and uniformly illuminate the target area, and the properties of the optical system and the spatial arrangement of the optical system with respect to the plurality of light sources is such that the light emitted by the plurality of light sources is mixed tangentially, and radial spread of the light is controlled, to uniformly illuminate the target plane over an area at least equal to that encompassed by the ring of light sources and the illumination extending uniformly from a center to a periphery of the target plane.
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27. A method of producing an illuminator comprising the steps of:
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mounting a plurality of light sources in a ring configuration, positioning an annular lens for directing light from the plurality of light sources onto a target plane, choosing the annular lens to have properties such that the lens mixes light from different light sources in the tangential direction and controls spread in the radial direction so that a center to a periphery of the target plane at a desired working distance is uniformly illuminated, separating the lens from the light sources by a predetermined distance, and choosing the light source ring diameter to lens diameter ratio to set a desired illumination area of the center to the periphery of the target plane. - View Dependent Claims (28)
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Specification