Linear array eye tracker
First Claim
1. A system for sensing movements of an eye in a living body, the eye having an iris surrounded by sclera with a limbus therebetween, the system comprising:
- a first linear photodetector having an elongate detector area, the detector area having an inner end and an outer end and defining an axis; and
a second linear photodetector having an elongate detector area, the detector area having an inner end and an outer end and defining an axis;
wherein the inner ends are alignable with the iris while the outer ends extend toward the sclera so that each linear detector is aligned across the limbus, the second linear detector being radially offset from the first linear detector relative to the aligned iris to measure displacement of the iris from therebetween.
6 Assignments
0 Petitions
Accused Products
Abstract
Improved devices, systems, and methods for sensing and tracking the position of an eye make use of the contrast between the sclera and iris to derive eye position. In many embodiments, linear photodetectors extend from the iris to the sclera. The eye is positioned between a pair of such linear photodetectors, and movement of the eye from one linear detector toward the other linear detector changes the relative amounts of light striking each linear detector. These pairs of linear photodetectors can accurately sense and measure one-dimensional positioning error and provide feedback to a one-dimensional positioning apparatus, resulting in a simple, highly linear system capable of accurate position tracking.
81 Citations
23 Claims
-
1. A system for sensing movements of an eye in a living body, the eye having an iris surrounded by sclera with a limbus therebetween, the system comprising:
-
a first linear photodetector having an elongate detector area, the detector area having an inner end and an outer end and defining an axis; and a second linear photodetector having an elongate detector area, the detector area having an inner end and an outer end and defining an axis; wherein the inner ends are alignable with the iris while the outer ends extend toward the sclera so that each linear detector is aligned across the limbus, the second linear detector being radially offset from the first linear detector relative to the aligned iris to measure displacement of the iris from therebetween. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A tracking system for maintaining alignment between an eye and a laser beam for use in laser eye surgery, the eye having an iris surrounded by a sclera, the tracking system comprising:
-
a first pair of linear photodetectors, each detector having an inner end oriented toward the iris and an outer end oriented toward the sclera, the first pair of linear detectors defining a first movement sensing axis therebetween; a second pair of linear photodetectors, each detector having an inner end oriented toward the iris and an outer end oriented toward the sclera, the second pair of linear detectors defining a second movement sensing axis therebetween; a processor coupled to the first and second pairs of detectors, the processor adapted to compare light signals from between the linear detectors of each pair for sensing movement of the iris along the sensing axis of the pair; and an actuation system coupled to the processor, the actuation system adapted to maintain alignment between the linear detectors and the eye. - View Dependent Claims (19, 20)
-
-
16. A method for sensing eye positions of a living body, the method comprising:
-
illuminating an iris and a sclera of an eye; measuring light from the illuminated eye with a plurality of linear photodetectors while the linear detectors are oriented radially so that each detector extends from adjacent the iris to the sclera; and comparing the light measured at a first detector to the light measured at a second detector to sense movement of the iris from therebetween. - View Dependent Claims (17, 18)
-
-
21. A method for tracking an eye of a living body, the method comprising:
-
illuminating an iris and a sclera of the eye; measuring light from the illuminated eye with a pair of linear photodetectors while the linear detectors are oriented radially so that each detector is aligned across a limbus to extend from adjacent the iris to adjacent the sclera; generating an error signal from a difference between light measured by the detectors of the pair; realigning the iris between the detectors using the error signal. - View Dependent Claims (22, 23)
-
Specification