field stop


Also found in: Acronyms.

field stop

[′fēld ‚stäp]
(optics)
An opening, usually circular, in an opaque screen, whose edges determine the limits of the field of view of an optical instrument.
References in periodicals archive ?
2 Field stop layer: When thin wafer is used for characteristics improvement, withstand voltage is insufficient.
With ON Semiconductor's proprietary Trench Field Stop Technology, we can now give engineers a greater breadth of options to choose from when implementing their power system designs.
The new IGBT technology and packaging innovation of Fairchild's 650V Field Stop Trench IGBT allows us to achieve all this.
In those cases I used a 7-mm orthoscopic eyepiece with opaque photography tape covering half of its tiny field stop, along with a 2x Barlow.
Observe when Sirius is highest in the south, use your highest magnification, hide Sirius's dazzle behind an occulting bar or the sharp edge of your eyepiece's field stop, and wait patiently for moments of good seeing--but you know that already.
Baader, however, has used a larger field stop than found in traditional orthoscopics, and this has increased the AFOV to 50[degrees].
This field stop is positioned at the eyepiece's focal plane and sharply defines the edge of your view when you look into the eyepiece.