Abstract: An illuminator is described which may be used with large inspection areas and which provides a dark field illumination pattern that is spatially uniform, illuminates from consistent angles, has high efficiency, and is smaller than existing solutions. A light pipe has a first end proximate an object to be illuminated and a second end opposite the first end and spaced from the first end. The light pipe also has at least one reflective sidewall. The first end of the light pipe includes an exit aperture and the second end has at least one opening to allow at least one image acquisition device to view the surface therethrough. At least one light source is configured to provide illumination in the light pipe. The object is illuminated by the first end of the light pipe by illumination at a selected elevation angle and substantially all azimuth angles.

Abstract: An illuminator is described which may be used with large inspection areas and which provides a dark field illumination pattern that is spatially uniform, illuminates from consistent angles, has high efficiency, and is smaller than existing solutions. A light pipe has a first end proximate an object to be illuminated and a second end opposite the first end and spaced from the first end. The light pipe also has at least one reflective sidewall. The first end of the light pipe includes an exit aperture and the second end has at least one opening to allow at least one image acquisition device to view the surface therethrough. At least one light source is configured to provide illumination in the light pipe. The object is illuminated by the first end of the light pipe by illumination at a selected elevation angle and substantially all azimuth angles.

Abstract: An illumination and imaging system is provided with a co-axial illuminator that does not include a beamsplitter. The co-axial illuminator achieves efficiencies substantially in excess of those achieved with a beamsplitter. In one aspect, an optical stop is used to reflect illumination upon a target. The optical stop includes an aperture allowing light reflected from the target to pass to a detector. The aperture of the stop has an asymmetrical feature that facilitates operation on specular targets.

Abstract: An illumination and imaging system is provided with a co-axial illuminator that does not include a beamsplitter. The co-axial illuminator achieves efficiencies substantially in excess of those achieved with a beamsplitter. In one aspect, an optical stop is used to reflect illumination upon a target. The optical stop includes an aperture allowing light reflected from the target to pass to a detector. The aperture of the stop has an asymmetrical feature that facilitates operation on specular targets.

Abstract: An illumination and imaging system is provided with a co-axial illuminator that does not include a beamsplitter. The co-axial illuminator achieves efficiencies substantially in excess of those achieved with a beamsplitter. In one aspect, an optical stop is used to reflect illumination upon a target. The optical stop includes an aperture allowing light reflected from the target to pass to a detector. The aperture of the stop has an asymmetrical feature that facilitates operation on specular targets.

Abstract: An electrostatic air cleaner has at least one hole in one of the plates over which air with charged dirt particles is passed. A light source is mounted adjacent to the hole so as to direct its light through the hole. A light sensor detects the level of light passing through the hole. As dirt particles deposit on the plate, they fill in the hole over a period of time, reducing the amount of light passing through the hole. It is possible by measuring the amount of light passing through the hole, to determine the amount of dirt deposited on the plate. In a preferred embodiment, each of the plates contain a hole in alignment with each of the other plates' holes so that light from a single light source can pass through each of the holes. Such a configuration allows both the light source and the light sensor to be located outside of the entire group of plates.