Particle detection system with coincident detection

A system for detecting particles or flaws on a surface of an article, comprising:

• means for transporting an article along a predetermined path of travel past an inspection zone;
• means for scanning a laser beam along a predetermined path in the inspection zone for passing across a surface of the article;
• a fiber optic bundle positioned or receiving and collecting light scattered from the surface of the article;
• a light splitter cooperating with said fiber optic bundle for splitting a beam of he collected light into first and second like light components each representative of the beam of the collected light;
• first and second photodetectors positioned for receiving respectively the first and second like light components;
• and
• electrical means of combining the output signals from said first and second photodetectors to form a combined output signal.

A system for detecting particles or flaws on a surface of an article, comprising:

• means for transporting an article along a predetermined path of travel past an inspection zone;
• means for scanning a laser beam along a predetermined path in the inspection zone for passing across a surface of the article;
• a dual output fiber optic bundle positioned for receiving and collecting light scattered from the airspace of the article and splitting a beam of the collected light into first and second like light components each representative of the beam of the collected light;
• first and second photodetectors positioned for receiving respectively the first and second like light components;
• and
• electrical means for combining the output signals from said first and second photodetectors to form a combined output signal.

A method for detecting particles or flaws on a surface of an article comprising the steps of:

• directing light onto a surface of an article;
• collecting light scattered from the surface of the article;
• splitting a beam of the thus collected scattered light into first and second like light components;
• optically detecting the first and second like light components to produce first and second detected output signals;
• and
• combining the first and second detected output signals to form a composite signal which is indicative of particles or flaws on the surface of the article.