US 5,489,985 AGranted

Apparatus for inspection of packaged printed circuit boards

AssigneeMatsushita Electric Industrial Co., Ltd.

InventorsShohroh Mochida, Tomohiro Kimura, Osamu Yamada, Yuji Ono, Hidenori Nagata

Life of this patent

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Abstract

There is provided an apparatus of inspecting a packaged state by scanning a packaged printed circuit board with a fine light beam and detecting reflection beams of the fine light beam in a plurality of directions. A fine light beam emitted from a light source is scanned on the packaged printed circuit board substantially vertically thereto by means of a polygon mirror and a light projection f.theta. lens. An optical path correcting system receives reflection beams scattered from the packaged printed circuit board and corrects optical paths of the reflection beams. The correction is done in such a way that reflection beams having constant directional vectors regardless of the change of the scanning position of the fine light beam are received and guided to light receiving positions complying with a height at a scanning position on a plurality of photoelectric conversion devices. Through this, the packaged state of parts is inspected at a high speed, with high accuracy and over a wide range without expanding the light receiving area of the photoelectric conversion device and without causing characteristics of triogonometrical survey to change with the scanning position.

Claims25

Dependent claims

An apparatus for inspection of a packaged printed circuit board, said apparatus comprising:

a light source for generating a light beam which is irradiated on a packaged printed circuit board to be inspected;
deflection means for deflecting said light beam generated from said light source to cause said light beam to scan said packaged printed circuit board;
a light projection lens system for irradiating said light beam deflected by said deflection means onto said packaged printed circuit board in a fixed direction such that said light beam is always parallel to said fixed direction when said light beam is incident on said packaged printed circuit board, reflection beams being scattered from said packaged printed circuit board from incident positions of said light beam on said packaged printed circuit board;
a plurality of optical path correcting means for receiving ones of said reflection beams having constant directional vectors relative to the fixed direction regardless of a change of the incident position of said light beam on said packaged printed circuit board and for guiding the received reflection beams such that said received reflection beams become parallel to said fixed direction;
a light receiving optical system for guiding a plurality of said reflection beams received by said plurality of optical path correcting means to said deflection means in parallel to each other;
and
photoelectric conversion means for receiving said reflection beams deflected by said deflection means and converting light quantities of the reflection beams received by said photoelectric conversion means into electrical outputs indicating respective heights of said light beam incident positions on said packaged printed circuit board.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/181,586Filed 14 Jan 1994
Priority: JP 5-00810521 Jan 1993
Granted: 6 Feb 1996
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G01B 11/00
Measuring arrangements characterised by the use of optical techniques
G01N 21/88
Systems specially adapted for particular applications: investigating the presence of flaws or contamination
G01R 31/309
Using non-ionising electromagnetic radiation, e.g. optical radiation: of printed or hybrid circuits or circuit substrates
G01R 31/2813
Specific types of tests or tests for a specific type of fault, e.g. thermal mapping, shorts testing: checking the presence, location, orientation…