Control of variable-focus lenses in a mixed-reality device for presbyopes
Variable-focus lenses are arranged as a lens pair that work on opposite sides of a see-through optical combiner used in a mixed-reality head-mounted display (HMD) device. An eye-side variable-focus lens is configured as a negative lens over an eyebox of the see-through optical combiner to enable virtual-world objects to be set at a close distance. The negative lens is compensated by its conjugate using a real-world-side variable-focus lens configured as a positive lens to provide an unperturbed see-through experience. For non-presbyopes, the powers of the lenses are perfectly offset. For presbyopes, the lens powers is mismatched at times to provide simultaneous views of both virtual-world and real-world objects on the display in sharp focus. Responsively an eye tracker indicating that the user is engaged in close viewing, optical power is added to the real-world-side lens to push close real-world objects optically farther away into sharp focus for the presbyopic user.
1. A method for operating an electronic device that includes an eye tracker and a mixed-reality see-through optical display system for showing scenes comprising virtual images that are rendered over views of real-world objects, the method comprising:
calibrating the electronic device for utilization by a presbyopic user;
operating the mixed-reality see-through optical display system to support a near field and a far field, the near field being closer to the presbyopic user relative to the far field, and the mixed-reality see-through optical display system having an eye side and a real-world side;
operating a conjugate pair of variable-focus lenses in matched configurations to provide for setting rendered virtual images within the near field without perturbing the views of the real-world objects in the far field;
using the eye tracker to determine a depth of the presbyopic user's gaze in the scene; and
responsively to a depth determination by the eye tracker, operating the conjugate pair of variable-focus lenses in mismatched configurations to enable the presbyopic user to simultaneously accommodate rendered virtual images and real-world objects in the near field.
2. The method of claim 1 in which the variable-focus lenses in the conjugate pair are located on opposite sides of the mixed-reality see-through optical display system, and in which the matched configurations comprise the conjugate pair of variable-focus lenses providing zero net optical power to the views of the real-world objects, and in which the mismatched configurations comprise optical power being added to the variable-focus lens disposed on the real-world side.
3. The method of claim 1 further comprising adding optical power to the variable-focus lens on the eye side to incorporate a corrective prescription of the presbyopic user for distance vision.
4. The method of claim 1 further comprising operatively coupling an optical power controller to the conjugate pair of variable-focus lenses.
5. The method of claim 4 further comprising operating the optical power controller to add optical power to the variable-focus lens on the eye side.
6. The method of claim 4 further comprising operating the optical power controller to add optical power to the variable-focus lens on the real-world side.
7. The method of claim 4 further comprising operatively coupling the eye tracker to the optical power controller, the eye tracker being configured for tracking vergence of the presbyopic user's eyes or tracking a gaze direction of at least one eye of the presbyopic user, in which the optical power controller controls the conjugate pair of variable-focus lenses responsively to operations of the eye tracker.
8. A head-mounted display (HMD) device wearable by a presbyopic user and configured for supporting a mixed-reality experience including viewing, by the presbyopic user, of virtual images from a virtual world that are combined with views of real-world objects in a physical world, comprising:
an eye tracker; and
a mixed-reality see-through optical display system for showing scenes comprising virtual images that are rendered over views of real-world objects,
wherein the HMD device is configured for
being calibrated for utilization by the presbyopic user;
operating the mixed-reality see-through optical display system to support a near field and a far field, the near field being closer to the presbyopic user relative to the far field, and the mixed-reality see-through optical display system having an eye side and a real-world side,
operating a conjugate pair of variable-focus lenses in matched configurations to provide for setting rendered virtual images within the near field without perturbing the views of the real-world objects in the far field,
using the eye tracker to determine a depth of the presbyopic user's gaze in the scene, and
responsively to a depth determination by the eye tracker, operating the conjugate pair of variable-focus lenses in mismatched configurations to enable the presbyopic user to simultaneously accommodate rendered virtual images and real-world objects in the near field.
9. The HMD device of claim 8 in which the variable-focus lenses in the conjugate pair are located on opposite sides of the mixed-reality see-through optical display system, and in which the matched configurations comprise the conjugate pair of variable-focus lenses providing zero net optical power to the views of the real-world objects, and in which the mismatched configurations comprise optical power being added to the variable-focus lens disposed on the real-world side.
10. The HMD device of claim 8 further comprising adding optical power to the variable-focus lens on the eye side to incorporate a corrective prescription of the presbyopic user for distance vision.
11. The HMD device of claim 8 further comprising operatively coupling an optical power controller to the conjugate pair of variable-focus lenses.
12. The HMD device of claim 8 further comprising operating the optical power controller to add optical power to the variable-focus lens on the eye side.
13. The HMD device of claim 11 further comprising operating the optical power controller to add optical power to the variable-focus lens on the real-world side.
14. A mixed-reality display system that is utilizable by a presbyopic user, the mixed-reality display system being operated to implement a method, comprising:
calibrating the mixed-reality display system for utilization by a presbyopic user, in which the mixed-reality display system is configured for showing scenes comprising virtual images that are rendered over views of real-world objects;
operating the mixed-reality display system to support a near field and a far field, the near field being closer to the presbyopic user relative to the far field, and the mixed-reality display system having an eye side and a real-world side;
operating a conjugate pair of variable-focus lenses in matched configurations to provide for setting rendered virtual images within the near field without perturbing the views of the real-world objects in the far field;
using an eye tracker to determine a depth of the presbyopic user's gaze in the scene; and
responsively to a depth determination by the eye tracker, operating the conjugate pair of variable-focus lenses in mismatched configurations to enable the presbyopic user to simultaneously accommodate rendered virtual images and real-world objects in the near field.
15. The mixed-reality display system of claim 14 in which variable-focus lenses in the conjugate pair are located on opposite sides of the mixed-reality see-through optical display system, and in which the matched configurations comprise the conjugate pair of variable-focus lenses providing zero net optical power to the views of the real-world objects, and in which the mismatched configurations comprise optical power being added to the variable-focus lens disposed on the real-world side.
16. The mixed-reality display system of claim 14 further comprising adding optical power to the variable-focus lens on the eye side to incorporate a corrective prescription of the presbyopic user for distance vision.
17. The mixed-reality display system of claim 14 further comprising operatively coupling an optical power controller to the conjugate pair of variable-focus lenses.
18. The mixed-reality display system of claim 17 further comprising operating the optical power controller to add optical power to the variable-focus lens on the eye side.
19. The mixed-reality display system of claim 17 further comprising operating the optical power controller to add optical power to the variable-focus lens on the real-world side.