Optical filtering system for a laser bar code scanner having narrow band-pass characteristics employing spatially separated filtering elements including a scanner window

摘要

A novel optical filtering system for a laser bar code scanner having narrow band-pass characteristics is disclosed. The optical filtering system has two different optical filtering elements which are disposed in a scanner housing in a spatially separate relationship. One of the optical filtering elements is positioned inside of the scanner housing in front of and close to the light detection element. The other optical filtering element is positioned in the light transmission aperture of the scanner housing and forms the scanning window. The optical filtering characteristics of the scanning window obscure the internal components of the scanner from plain view making the scanner appear more aesthetically pleasing. Together the optical filtering element cooperate to form a narrow-band pass filter to provide for better light collection and scanning.