Abstract: A top illumination photoelectric measuring installation to determine the relative positions of two objects is disclosed which includes an optical reflection grid scale and a transmission grid sensor plate laterally with respect to each other and photoelectric elements to receive light reflected from the scale. In this installation, the photoelectric elements are arranged to accomplish a vignetting of the photo-sensitive surface of the photoelectric elements whenever the operating distance between the scale and the sensor plate is such that further movement of the scale and the sensor plate toward one another would produce a photo current greater than that which can be tolerated by the amplifier connected to the photo elements and provided that the admissable range of tolerance is not exceeded. Such an arrangement permits a greater range of operating distances between the sensor plate and the scale than could be achieved under a normal operating arrangement.

Abstract: An optical apparatus, particularly suited for use in a ballistic measurement device, including a laser generating a laser beam, an optical means for expanding the laser beam in a plane, and an optical element, positioned between the laser and the optical means, for dividing the laser beam into a plurality of beams of substantially identical intensity so that a substantially uniform brightness results over the entire angle of divergence of the laser beam.

Abstract: A longitudinal measuring instrument, preferably with digital path coverage, which is constructed according to the Abbe principle. The measuring instrument includes a stationary scale, a displaceably mounted scanning unit for scanning the scale, and a measuring spindle sleeve mounted on the scanning unit, said measuring spindle comprising at least two bars which surround the scale.