US 5,671,043 AGranted

Optical position detector for determining the angular position of a rotatable element

AssigneeCambridge Technology, Inc.

InventorRichard Ivers

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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.

Claims16

Dependent claims

A position detection system for determining the angular position of a rotatable element extending in an axial direction, said system comprising:

a first light source and a second light source, each positioned proximate one end of the rotatable element;
detecting means optically aligned with said first and second light sources for receiving light therefrom and for providing an output indicative of the amount of light received by said detecting means from said light sources;
means connected to said one end of the rotatable element for preventing a preselected amount of light emanating from said first and second light sources from being received by said detecting means;
said detecting means comprising four light detecting components, a first pair of said light detecting components being operably interrelated with said first and second light sources and a second pair of said light detecting components being operably interrelated with said first and second light sources, whereby said output of said detecting means is virtually unaffected by any unwanted radial movement of the rotatable element;
said means for preventing a preselected amount of light from being received by said detecting means comprising an opaque element extending in said axial direction from the rotatable element and being interposed between said first and second light sources and said four light detecting components;
and
means for receiving said output from said detecting means and providing a signal indicative of the angular position of the rotatable element.

4 more elements

A position detection system for determining the angular position of a rotatable element extending in an axial direction, said system comprising:

a first light source and a second light source, each positioned proximate one end of the rotatable element and positioned diametrically opposed from one another;
four light detectors optically aligned with said first and second light sources for receiving light therefrom and for providing an output indicative of the amount of light received;
said four light detectors being in the form of two pairs of light detectors operably interrelated with one another;
an opaque flat element connected to said one end of the rotating element and extending in said axial direction from said rotatable element for preventing a preselected amount of light emanating from said first and second light sources from being received by said two pair of light detectors;
an opaque baffle surrounding each of said light sources for preventing unwanted light from striking said light detectors;
a first pair of said two pair of light detectors being operably interrelated with said first and second light sources and a second pair of said two pair of said light detectors being operably interrelated with said first and second light sources, whereby said output of said detecting means is virtually unaffected by any unwanted radial movement of the rotatable element;
and
means for receiving said output from said light detectors and providing a signal indicative of the angular position of said rotating element.

5 more elements

Dependencies are inferred from the claim text.