At&t Bell Laboratories

At&t Ipm Corp.

American Telephone and Telegraph Corporation

Joseph S Kovalchick

Ralph A Treder

George T Harvey

Michael K Bartschat

Theodore J Sikorski

The parallelism of two nominally parallel surfaces is determined by placing a planar reflector (50) on one surface and a cube beam splitter (52) on the other surface. The reflector is placed to reflect light in a direction normal to the plane of the reflector. The cube beam splitter is placed to reflect part of the light striking a first face (54) back in the opposite direction. The cube beam splitter also reflects part of the incident light towards the reflector so that the reflector reflects the light back to the cube beam splitter, causing the light to exit the first cube beam splitter face. An autocollimator (10) is provided to direct a beam of light (24) into the first face (54) of the cube beam splitter (52) and to display the divergence between the first and second reflected beam portions, the divergence corresponding to the degree of non-parallelism between the two surfaces.

Method and apparatus for measuring the parallelism of two surfaces

A system (10) for precisely placing a semiconductor chip (16) on a substrate (11) includes a robotic arm (18) which is provided with a gripper (22) for separately picking up the chip and substrate. A first television camera (38) is carried by the robotic arm and serves to capture the image of the substrate to locate a pair of datum points (71a and 71b) thereon. A second camera (40), stationary with respect to the robotic arm, serves to capture the image of the chip (16), when engaged by the robot, to locate each of a pair of datum points (83a and 83b) thereon. A machine vision system (46) serves to process the output signal of the cameras (38) and (40) to establish the precise location of the datum points on the substrate and on the chip. The information from the vision system (46) is employed to control the robotic arm to cause the gripper to place the chip on the substrate such that each of the datum points on the substrate is at a prescribed location relative to a separate one of the datum points on the chip.

Method and apparatus for chip placement

The color of each of a plurality of wires 18(1) . . . 18(8) can be determined by first placing the wires proximate to a white background (31) and then directing a pair of light beams (36,38) thereat. Each of the red, green and blue spectral components in the light reflected from each wire and in the light reflected from the surface is simultaneously sensed by a separate one of three television cameras (40,42 and 44), respectively, having a separate one of a set of red, green and blue band pass filters (52,54 and 56), respectively, thereon. The output signal of the television cameras is processed by a machine vision system (58) which first computes the ratios of the red, green and blue spectral components of the light reflected from each wire to the red, green and blue spectral components, respectively, of the light reflected from the background. Each of the red, green and blue intensity ratios computed for each wire is then compared by the machine vision system to a red, green and blue intensity ratio, respectively, established for each of a plurality of wires of known colors until a substantial match therebetween is found. When a substantial match is found, the wire of unknown color can then be identified.

Growing community of inventors

Germansville, PA, United States of America

Joseph S Kovalchick