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Laser Bent-Pin Detector

IP.com Disclosure Number: IPCOM000039950D
Original Publication Date: 1987-Aug-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Voyles, RM: AUTHOR

Abstract

The robotic insertion of pinned modules into printed circuit boards requires a method of detecting bent pins on the module before insertion into the module's socket. Because the edges of straight pins are parallel they produce colinear diffraction patterns forming one narrow band of light. A bent pin produces a light pattern which is skewed with respect to the pattern of the straight pins. The application of a laser, as a light source, and an optical array detector, to detect the light pattern generated by bent pins, works in the following manner. A laser 1 emits a laser beam 2 in the direction of an optical array detector 3. A robot gripper 4, having jaws 5 for gripping a module 6, moves module 6 in a vertical scanning motion, as indicated by arrow A.

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Laser Bent-Pin Detector

The robotic insertion of pinned modules into printed circuit boards requires a method of detecting bent pins on the module before insertion into the module's socket. Because the edges of straight pins are parallel they produce colinear diffraction patterns forming one narrow band of light. A bent pin produces a light pattern which is skewed with respect to the pattern of the straight pins. The application of a laser, as a light source, and an optical array detector, to detect the light pattern generated by bent pins, works in the following manner. A laser 1 emits a laser beam 2 in the direction of an optical array detector 3. A robot gripper 4, having jaws 5 for gripping a module 6, moves module 6 in a vertical scanning motion, as indicated by arrow A. As gripper 4 moves module 6 through the vertical path, pins 7 on module 6 are likewise moved through the fixed horizontal laser beam 2. The gripper makes four vertical movements (up, down, up, down). Before each vertical movement, the gripper is rotated to one of four orientations (0o, 90o, +20o, -20o), as indicated by arrow B. The resulting diffraction patterns are captured by the optical array detector 3 and then relayed to an IBM Personal Computer (PC) 8 through a parallel interface 9. The resulting images, which are captured at a rate of three frames between adjacent pins, are examined by software on the PC for specific types of patterns to determine those pins 7 that are bent in excess...