High numerical aperture line scanning system

In order to scan a line, the scanning optics usually employs either NSG's SELFOC lens or a 1:1 lenslet array. Each of these two methods has its limitation. The SELFOC lens' numerical aperture (NA) is low, which limits its light-collection efficiency. A 1:1 lenslet array can have a high NA, but its resolution along the scanning direction is low, which means it is not suitable for 2-D scanning. In this paper, line scan optics with a high NA will be discussed. Unlike the above-mentioned methods, this method has the same high resolution in both line and scan directions. It has a 1:-1 (preferred 1:<-1) relationship between the object and the image. A number of groups of lenses, based on the length of the object, is required and are arranged along a single plane. The field of each group is equal to or slightly larger than the diameter of the lens. Each group of lenses images a segment of the object onto the image plane. The magnification of each group should be less than 1:-1, for example, 1:-0.95, so that the image of each segment will not overlap in the sensor when one long sensor is used, or it will not be larger than the sensor when each group has its own sensor. After the image of each segment is read from the sensor, it is reverted and, with the help of image processing, all of the images are connected together to form an image of the whole line.