Ming Lai

Author:

Ming Lai

ISBN #:

0837166853

US Patent:

6367931, Apr 9, 2002

Filed:

Dec 19, 2000

Appl. No.:

09/741407

Inventors:

Ming Lai - Dublin CA 94568

International Classification:

A61B 314

US Classification:

351209

Abstract:

An optical tracking device and method are disclosed for tracking lateral movement of an object. A scanning probe beam and a time-resolved detection are implement in the disclosed technique. A particular application is for tracking the eye movement during a laser surgery.

US Patent:

6382793, May 7, 2002

Filed:

May 20, 2000

Appl. No.:

09/575421

Inventors:

Ming Lai - Dublin CA
Ning Y. Chan - Berkeley CA
Jay Wei - Fremont CA

Assignee:

Carl Zeiss, Inc. - Thornwood NY

International Classification:

A61B 314

US Classification:

351206

Abstract:

Embodiments of the present invention provide method and apparatus for measuring a wavefront of a beam of radiation. In particular, one embodiment of the present invention is an apparatus for measuring a wavefront of a beam of radiation at a first plane which includes: (a) relay optics adapted to relay the wavefront from the first plane to a second plane; (b) a moving boundary locus apparatus disposed between the first and second planes; (c) a two-dimensional photodetector array comprisingâat least 4Ã4 photodetector elements disposed in the second plane, wherein each photodetector element produces a time varying signal in response to movement of a portion of the moving boundary locus apparatus; (d) a synchronizer adapted to synchronize each of the time varying signals with a position of the portion of the moving boundary locus apparatus; and (e) an analyzer, responsive to synchronized time varying signals output from the synchronizer, to measure the wavefront of the beam.

US Patent:

6382794, May 7, 2002

Filed:

Sep 27, 1999

Appl. No.:

09/406034

Inventors:

Ming Lai - Dublin CA
Barry T. Kavoussi - Danville CA
Christopher J. R. V. Baker - Moraga CA

Assignee:

Carl Zeiss, Inc. - Thornwood NY

International Classification:

A61B 310

US Classification:

351212

Abstract:

Method and apparatus is disclosed for mapping a corneal contour and thickness profile. In accordance with one aspect of the present invention, a set of narrow, collimated, parallel beams is projected onto a corneal surface at an angle with respect to a predetermined axis (âan instrument axisâ) that is substantially aligned with a visual axis of an eye. The set of beams is rotated about the instrument axis. A CCD camera is disposed to view the cornea along the instrument axis. Traces of the rotating set of beams form a set of rings in images obtained by the CCD camera; wherein outer and inner edges of the rings correspond to intersections of the set of beams with anterior and posterior surfaces of the cornea, respectively. Next, a direct triangulation algorithm is used to determine spatial positions of data points along the outer edges of the rings, and these spatial positions are used to reconstruct the anterior surface profile of the cornea. Next, using the anterior surface profile of the cornea, a ray tracing triangulation algorithm is used to determine spatial positions of data points along the inner edges of the rings, and these spatial positions are used to reconstruct the posterior surface profile of the cornea.

US Patent:

6382795, May 7, 2002

Filed:

May 20, 2000

Appl. No.:

09/576082

Inventors:

Ming Lai - Dublin CA

Assignee:

Carl Zeiss, Inc. - Thornwood NY

International Classification:

A61B 310

US Classification:

351212

Abstract:

Embodiments of the present invention advantageously satisfy the above-identified need in the art, and provide method and apparatus for measuring refractive errors of an eye that improve upon wavefront type refractors using a conventional Hartmann-Shack sensor. Specifically, one embodiment of the present invention is an apparatus for measuring refractive errors of an eye which includes: (a) a source of a probe beam; (b) a first Badal lens system adapted to project the probe beam into a subjects eye to form an illumination spot on a retina; (c) a second Badal lens system adapted to image the illumination spot onto an image plane substantially conjugate to the retina; and (d) a spatial filter disposed in the image plane adapted to transmit at least a portion of the image.

US Patent:

6406146, Jun 18, 2002

Filed:

Sep 21, 2000

Appl. No.:

09/667180

Inventors:

Ming Lai - Dublin CA

Assignee:

Carl Zeiss, Inc. - Thornwood NY

International Classification:

A61B 314

US Classification:

351206

Abstract:

Wavefront refractor apparatus and method which records two Hartmann-Shack images simultaneously at different distances from the lenslet array. The two images recorded this way enable each focal spot to be associated with a lenslet forming the spot to identify âbadâ spots, âghostâ spots, and to provide more accurate measurements for diverging or converging wavefronts.

US Patent:

6407872, Jun 18, 2002

Filed:

Feb 16, 2001

Appl. No.:

09/784834

Inventors:

Ming Lai - Dublin CA
Jay Wei - Fremont CA
Manish D. Kulkarni - San Ramon CA
Kabir M. Arianta - Livermore CA

Assignee:

Carl Zeiss, Inc. - Thornwood NY

International Classification:

G02B 504

US Classification:

359833, 211213, 211837

Abstract:

One embodiment of the present invention is an optical path length scanner which includes: (a) a set of prisms mounted evenly along a movable carrier; and (b) a mechanism that drives the movable carrier to move.

US Patent:

6575572, Jun 10, 2003

Filed:

Sep 21, 2001

Appl. No.:

09/960113

Inventors:

Ming Lai - Dublin CA
Jay Wei - Fremont CA
Scott A. Meyer - Livermore CA
James P. Foley - Fremont CA
Jochen M. Horn - Pleasanton CA

Assignee:

Carl Zeiss Ophthalmic Systems, Inc. - Dublin CA

International Classification:

A61B 310

US Classification:

351211

Abstract:

Embodiments of the present invention provide a method and apparatus for measurement of aberration of an eye. One or more embodiments provide an aberration measurement instrument that enables measurement wherein Hartmann-Shack spots have reduced speckle; one or more embodiments provide an aberration measurement instrument that enables measurement of an eye having a large diopter power variation over different zones of the eye; one or more embodiments provide an aberration measurement instrument that enables measurement with accommodation control; one or more embodiment provide an aberration measurement instrument wherein radiation reflected by a cornea and radiation scattered by intra-ocular elements are blocked; and one or more embodiment provide an aberration measurement instrument wherein a hazy background produced by radiation multiply scattered within an eye is reduced.

US Patent:

6575573, Jun 10, 2003

Filed:

Oct 17, 2001

Appl. No.:

09/981054

Inventors:

Ming Lai - Dublin CA
Jay Wei - Fremont CA

Assignee:

Carl Zeiss Ophthalmic Systems, Inc. - Dublin CA

International Classification:

A61B 310

US Classification:

351212, 351214

Abstract:

Embodiments of the present invention provide a method and apparatus for measurement of a corneal profile of an eye. In particular, one embodiment of the present invention is a corneal diagnostic instrument including: (a) a Placido ring illuminator disposed to project radiation onto a cornea to generate a Placido ring image; (b) multiple slit lamp projectors disposed to project slit light beam images onto the cornea to generate slit light beam images; (c) a camera system optically disposed to detect the Placido ring image and the slit light beam images; and (d) a controller, coupled to the slit lamp projectors, the Placido ring illuminator, and the camera system, to cause the slit light beam images and the Placido ring image to be generated and detected in a predetermined sequence, wherein the controller is responsive to the detected Placido ring image and the detected slit light beam images to determine a corneal thickness profile.