Method of producing numerical control data for inspecting assembled printed circuit board

• US 5,134,575 A
• Filed: 12/21/1990
• Issued: 07/28/1992
• Est. Priority Date: 12/21/1989
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Takagi, Yuuji
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US07/631,983
• Time in Patent Office: 585 Days
• Field of Search: 364/551.01, 364/552, 364/560, 364/561, 364/559, 364/488, 364/489, 364/490, 364/491, 364/151, 364/150, 364/190, 364/191, 364/579, 364/571.04, 382/8, 356/375, 356/384, 356/387, 356/394, 358/106, 358/107
• US Class Current: 382/147
• CPC Class Codes: G05B 19/4083 Adapting programme, configuration
• CPC Class Codes: G06T 2207/30141 Printed circuit board [PCB]
• CPC Class Codes: G06T 2207/30152 Solder
• CPC Class Codes: G06T 7/0004 Industrial image inspection

Abstract

Predetermined NC data for inspection including data of a predetermined location of an electronic component to be mounted on a PCB is stored in a microcomputer. A signal representing the image of the PCB on which no electronic component is yet mounted is obtained by using a television camera. From the obtained image signal of the PCB, the patterns of pads for mounting electronic components on the PCB is extracted. On the basis of the extracted pad patterns, the optimum location of the electronic component to be mounted is specified. The NC data of the electronic component location which is stored in the microcomputer is corrected according to the result of the specification.

Claims

1. A method of producing numerical control data for inspection in which, by using imaging means for picking up an image of a printed circuit board on which electronic components are mounted, positioning means for moving the printed circuit board into the visual field of said imaging means and holding the printed circuit board motionless in the visual field and means for controlling said positioning means so that the image information on a desired part of the printed circuit board may be obtained by said imaging means, the state of electronic components mounted on the printed circuit board is inspected on the basis of the image information delivered out of said imaging means, said method comprising the steps of:

storing in a memory in said control means predetermined numerical control data for inspection including data of predetermined locations of electronic components to be mounted on a printed circuit board;

obtaining image information on the printed circuit board on which no electronic component is mounted yet, by using said imaging means;

extracting patterns of pads for mounting electronic components on the printed circuit board from the obtained image information on the printed circuit board;

providing an inspection window for checking soldering, said window fitting between the extracted patterns of pads; and

storing in said memory in said control means the location and the size of the provided window as part of numerical control data for inspection.

2. A method of producing numerical control data for inspection in which, by using imaging means for picking up an image of a printed circuit board on which electronic components are mounted, positioning means for moving the printed circuit board into the visual field of said imaging means and holding the printed circuit board motionless in the visual field and means for controlling said positioning means so that the image information on a desired part of the printed circuit board may be obtained by said imaging means, the state of electronic components mounted on the printed circuit board is inspected on the basis of the image information delivered out of said imaging means, said method comprising the steps of:

storing in a memory in said control means predetermined numerical control data for inspection including data identifying predetermined locations at which electronic component are to be mounted on a printed circuit board;

obtaining image information on the printed circuit board on which no electronic component is mounted yet, by using said imaging means;

extracting patterns of pads for mounting electronic components on the printed circuit board from the obtained image information on the printed circuit board;

classifying a plurality of pads in the extracted patterns into a plurality of groups of pads, each of said groups of pads corresponding to a respective one of said electronic components to be mounted thereon;

measuring the distance between at least one pad in a first group of pads for mounting a first electronic component and at least one pad in a second group of pads for mounting a second electronic component;

providing an inspection window for checking solder bridging between said at least one pad in said first group of pads and said at least one pad in said second group of pads, only when the measured distance between said at least one pad of said first group and said at least one pad of said second group is shorter than a predetermined value; and

storing in said memory in said control means the location and the size of the provided window as part of numerical control data for inspection.