Surface particle detector


Contamination detection and quantification requirements have become increasingly important, particularly with the rapid evolution of high-tech industries. In an effort to control and minimize contamination in crucial stages of a production process, cleanrooms are frequently used. It is important to monitor the cleanliness/contamination levels in a cleanroom, especially for detecting particles on a cleanroom surface.

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This invention relates to particle counting for cleanroom applications, and relates more particularly to an improved device for moving particles off of a surface and into a particle counter and a filter for the purpose of ascertaining contamination levels.

The device includes a scanner, a particle counter, a conduit connecting the two, a sensor and a controller. The particle counter includes a pump for producing an air stream flowing from the scanner opening, through the particle counter, and back to the scanner for carrying the particles to the particle counter for quantitation. The particle counter also includes a removable filter cartridge with a filter element that captures the counted particles for laboratory analysis.

The device described above is used to obtain a relative cleanliness level by quantitating the released particles from surfaces. Possible test surfaces include tables, shelves, walls, ceilings, benches, product containers or virtually any other kind of surface. Different scanner geometries can be employed for customizing the device to the particular sample surface of interest. The technique can be used to verify cleanliness prior to undertaking some type of cleanroom procedure, or to evaluate or compare the effectiveness of various cleaning techniques and products.

The figure shows a perspective view of the particle detector (A) for analyzing particles on a sample surface. The main detector components include a particle counter assembly (not shown), a housing (B) surrounding the particle counter assembly, a scanner probe (C), and conduit (D) connected between the particle counter assembly and probe.

United States Patent: 7,010,991

Inventors: Donald G. Lutz (San Ramon, Calif.); Daniel Duggan (Danville, Calif.)

Date: March 14, 2006