(12) United States Patent ao) Patent No.: Us 7,248,374 B2
Bridges (45) Date of Patent: Jul. 24,2007
(54) SPHERICALLY MOUNTED LIGHT SOURCE WITH ANGLE MEASURING DEVICE, TRACKING SYSTEM, AND METHOD FOR DETERMINING COORDINATES
(75) Inventor: Robert E. Bridges, Kennett Square, PA (US)
(73) Assignee: Faro Laser Trackers LLC, Kennett Square, PA (US)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 81 days.
(21) Appl. No.: 10/372,452
(22) Filed: Feb. 24, 2003
(65) Prior Publication Data
US 2003/0227616 Al Dec. 11, 2003
Related U.S. Application Data
(60) Provisional application No. 60/358,930, filed on Feb. 22, 2002.
(51) Int. CI.
G01B 11/26 (2006.01)
(52) U.S. CI 356/614; 356/139.08; 356/141.1
(58) Field of Classification Search 356/614,
356/139.01, 139.03, 139.07, 139.08, 139.1, 356/141.1, 141.2, 4.09, 141.4, 138 See application file for complete search history.
(56) References Cited
U.S. PATENT DOCUMENTS
4,202,321 A * 5/1980 Volna 126/605
4,820,041 A * 4/1989 Davidson et al 356/3.12
4,912,336 A * 3/1990 Nayar et al 250/559.17
4,977,488 A * 12/1990 Spotts et al 362/183
A device for use in conjunction with a coordinate measuring device, a three-dimensional coordinate measuring system and a method of measuring three-dimensional coordinates are described. The device includes a light source mounted substantially within the center of a spherical member having a spherical surface configured such that the distance from the light source to the outer contact surface of the sphere is substantially equal to the radius of the sphere regardless of sphere orientation. The three-dimensional coordinate measuring system further includes a coordinate-measuring device, the coordinate-measuring device configured to track the movement of the light source and to measure either azithmuth angles and zenith angles, or to spherically encode tracking information related to relevant positions of the light source. The present method includes emitting light at a target with a light source, wherein the light source is mounted substantially within the center of a spherical member having a spherical surface configured such that the distance from the light source to the outer contact surface of the sphere is substantially equal to the radius of the sphere regardless of sphere orientation, moving the surface of the spherical member across a device to be measured, tracking said light source with a tracking device, and measuring information related to the relative position of the light source using either angular or spherical encoders.