Richard J Ivers

US Patent:

56710437, Sep 23, 1997

Filed:

Oct 3, 1995

Appl. No.:

8/538202

Inventors:

Richard Ivers - West Newton MA

Assignee:

Cambridge Technology, Inc. - Cambridge MA

International Classification:

G01D 534

US Classification:

356138

Abstract:

An optical position detector for determining the angular position of a rotating element and being virtually insensitive to any unwanted radial movement of the rotating element. The position detector having a first light source and a second light source, each positioned proximate one end of the rotating element and positioned diametrically opposed from one another. Four light detectors are optically aligned with the first and second light sources for receiving light therefrom and for providing an output indicative of the amount of light received. An opaque flat element being interconnected to the one end of the rotating element for preventing a preselected amount of light emanating from the first and second light sources from being received by the light detectors. The first and second light sources and the light detectors cooperating with each other in such a manner that the output from the light detectors is virtually unaffected by any unwanted radial movement of the rotating element. The output from the light detectors is received by a circuit which provides a signal indicative of the angular position of the rotating element.

US Patent:

58446737, Dec 1, 1998

Filed:

Apr 17, 1998

Appl. No.:

/061935

Inventors:

Richard J. Ivers - West Newton MA

Assignee:

Cambridge Technology, Inc. - Cambridge MA

International Classification:

G01D 534

US Classification:

356138

Abstract:

A position detector for determining the angular position of a rotatable element, the detector having a single light source for directing a uniform wide angle field of light in a direction generally along the longitudinal axis of the rotatable element, multiple sector-shaped light detectors aligned circumferentially about the rotatable element to receive light directly from the source, and a light blocker connected to the rotatable element to rotate therewith about the longitudinal axis for periodically blocking portions of the light which impinge upon the light detectors from the light source. The space between the light source and the detectors being essentially free of any object, except for the light blocker, so that the light from the light source can impinge directly upon at least those portions of the detectors which the light blocker is not blocking, without passing through any other object. A linear output of each of pairs of connected detectors being utilized to provide a reliable measurement of the angular position of the rotatable element.