Patent ID: 11914161
Assignee: LUMUS LTD.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 11:
12. An apparatus, comprising:
a light-transmitting substrate having a pair of parallel major surfaces for guiding light by internal reflection, a first of the major surfaces being deployed in facing relation to an eye of a viewer;
a lens associated with the first of the major surfaces, the lens configured for selectively applying optical power to incident light according to a polarization direction:
the lens applies optical power to incident light returned from the eye that is polarized in a first polarization direction so as to collimate the incident light returned from the eye that is polarized in the first polarization direction, and
the lens applies substantially no optical power to incident light coupled out of the light-transmitting substrate that is polarized in a second polarization direction orthogonal to the first polarization direction;

an illumination arrangement deployed to illuminate the eye with light that is polarized in the first polarization direction such that a proportion of the light that is polarized in the first polarization direction is reflected by the eye back toward the lens so as to be collimated by the lens;
an optical module including:
a reflective-display device that produces light, corresponding to an image and that is polarized in the second polarization direction, in response to illumination from a source of light,
optics configured for collimating the light produced by the reflective-display device so as to produce collimated light that is polarized in the second polarization direction, and
an optical sensor;

an optical coupling configuration configured for coupling the collimated light that is polarized in the second polarization direction into the light-transmitting substrate so as to propagate within the light-transmitting substrate by internal reflection in a first propagation direction;
a plurality of partially reflective surface deployed within the light-transmitting substrate obliquely to the major surfaces of the light-transmitting substrate, the partially reflective surfaces configured for:
coupling-out a proportion of light that is polarized in the second polarization direction, propagating within the light-transmitting substrate in the first propagation direction, and
coupling-in a proportion of the collimated light that is polarized in the first polarization direction incident on the first of the major surfaces, so as to propagate within the light-transmitting substrate in a second propagation direction, wherein the optical coupling configuration is further configured for coupling-out the propagating light that is polarized in the first polarization direction; and

at least one processor electrically coupled to the optical sensor,
wherein the optics of the optical module are further configured for receiving the light coupled-out by the optical coupling configuration and for converting the coupled-out light into converging beams of captured light, wherein the optical sensor is configured for sensing the captured light, and wherein the at least one processor is configured to process signals from the optical sensor to derive a current gaze direction of the eye.