Helmet mounted eye tracker using a position sensing detector

Claim 1

An eye tracker for monitoring movement of an eye's cornea comprising, in combination: source means having an output adapted for projecting a pulsed infrared light beam having a predetermined frequency along a first predetermined light path; reflecting means spatially disposed downstream from said source means along said first light path adapted for redirecting said pulsed infrared light beam along a second predetermined light path, and for receiving and redirecting along said first light path a virtual image formed within said eye; infrared beam splitting means spatially disposed downstream from said reflecting means along said second light path adapted for redirecting said pulsed infrared light beam onto the cornea of said eye that is positioned along a third predetermined light path so as to form said virtual image that changes position upon movement of the cornea of said eye, for receiving the virtual image formed within said eye, and for redirecting the virtual image formed within said eye along said second light path; infrared sensing means positioned upstream from said source means along said first optical path, and having a field of view and an output adapted for receiving the virtual image formed within said eye, and for providing at the output thereof a plurality of square wave signals indicative of the X and Y coordinate positions of the cornea of said eye within the field of view of said sensing means; and collecting lens means positioned between said source means and said sensing means along said first light path adapted for focusing the virtual image formed within said eye upon the field of view of said sensing means.