An Automatic Optical Printed Circuit Inspection System

Robert C. Restrick III

doi:10.1117/12.955644

15 December 1977 An Automatic Optical Printed Circuit Inspection System

Robert C. Restrick III

Proceedings Volume 0116, Solid-State Imaging Devices; (1977) https://doi.org/10.1117/12.955644
Event: 21st Annual Technical Symposium, 1977, San Diego, United States

Abstract

With the trend toward higher circuit density and finer lines, printed circuit inspection becomes more important both in terms of assuring adequate functional capability, as well as long term reliability. Visual inspection of such circuits in a high volume production environment becomes more difficult, prone to error, and expensive. Automatic optical inspection appears to provide the only effective means of performing this operation. Such a method has application not only for final product inspection, but also for inspection at intermediate stages of production including art work inspection. A practical system must be able to convert the printed circuit pattern into a binary two-dimensional representation and then to process this representation to detect flaws. Development of the binary representation is hindered by the low optical contrast presented by many printed circuit material systems. The detection of flaws depends on selecting error criteria that are indicative of circuit quality, and that are practical to implement. This paper describes a prototype automatic inspection system which uses minimum line width and line clearance criteria. This system provides high resolution and uses linear solid state arrays for sensors. The conversion to a binary representation is made after correcting for system spatial nonuniformities in the illumination, optics, and sensing elements. Internal registers, which are continually being updated, are used to store successive scans of the image. At the same time, the contents of the registers are processed in parallel using combinatorial logic to implement the error criteria.

Citation Download Citation

Robert C. Restrick III "An Automatic Optical Printed Circuit Inspection System", Proc. SPIE 0116, Solid-State Imaging Devices, (15 December 1977); https://doi.org/10.1117/12.955644

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available