Patent ID: 8164813

Claim:
A continuous variable aperture for an infra-red camera, comprising: a pair of positionable blade members for defining an aperture, said aperture being of an area that is selectively adjustable in size and, when said aperture is open, is of a generally rectangular shape, the size of said area being a function of the position of said positionable blade members relative to one another; and an actuator for selectively positioning said positionable blade members relative to one another to any position within a continuum of positions to selectively adjust said area of said adjustable aperture, wherein said generally rectangular shape of said aperture further comprises a rectangle to define a rectangular aperture; and further comprising: a plurality of additional positionable curved blade members for rounding the corners of said rectangular aperture, irrespective of the size of said aperture, to produce a generally race track shaped aperture, said additional positionable curved blade members including a curved edge; and wherein said actuator controls positioning said plurality of additional curved blade members concurrently in synchronism with the positioning of said pair of positionable blade members.