Iris Diaphragms

Control of aperture is easily accomplished by means of a variable diameter iris diaphragm.  Overlapping thin steel blades restrict the diameter of an optical component.  The aperture approximates more closely to a circle if more blades are used.  Typically the number of blades ranges from 5 to 20.    The blades are contained in a metal housing (usually brass, but aluminium is used for larger diameters) and a protruding lever is used to adjust the iris aperture.

Normally an iris does not completely close but special forms of iris with two sets of blades can be supplied when fully closing apertures are needed.

Standard irises are available in brass housings with maximum apertures of: 5, 8, 12, 15, 18, 20, 22, 25, 28, 30, 34, 36, 37, 41, 42, 50 and 58 mm.

 Fully closing irises in brass housings are available with maximum apertures of: 12, 25, 37 and 50 mm.

 Standard irises in aluminium housings are available with maximum apertures of: 70, 75, 80.5, 90, 98, 104, 110, 120, 138, 158 and 224 mm.

Datasheet       Back Up Next      Inquiry