Distance-measuring interferometer

Claim 2

An interferometer for detecting and indicating motion of an object comprising: light reflector means coupled to the object in a manner for movement therewith upon displacement of the object; means for causing a first light beam having a predetermined polarization to impinge upon said reflector means; said reflector means adapted for reflecting the impinging light beam; means for causing a second light beam having a same predetermined polarization and orthogonally related with respect to the reflected beam to combine with the reflected beam and to provide a resultant linearly polarized light beam having a plane of polarization rotatable upon displacement of the object; and, means for operating on said uniformly polarized light beam to provide an electrical output signal having a frequency modulation component varying in accordance with the velocity of displacement of the object and for detecting said modulation component to provide an indication of the velocity of displacement of said object.

Claim 3

The interferometer of claim 1 wherein said transmission means includes reflective surface means mounted on said object and positioned along said path of variable length.

Claim 4

In an interferometer for measuring distance: a light reflector means coupled to a movable object for movement therewith, said reflector means having reflective surfaces adapted for reversing the direction of propagation of a polarized impinging light beam along a path differing from an incident beam path and for reversing the direction of polarization thereof; a light beam splitter adapted for dividing an impinging light beam into transmitted and reflected components; light source means including a laser light source arranged for causing polarized light which is polarized in a first direction to impinge upon said beam splitter; a light beam combination means; said beam splitter positioned with respect to said reflector means and with respect to said light beam combination means for causing a transmitted light component to impinge upon said reflector means and for directing a reflected component from said first beam splitter to said light beam combination means whereby the transmitted and reflected beams are of substantially equal intensity; said light beam combination means positioned with respect to said first beam splitter and with respect to said reflector means for causing a combination of a reflected light component from said first beam splitter and a reflected light component from said reflector means and for providing a resultant linearly polarized light beaM having a plane of polarization rotatable in accordance with motion of the object; means disposed in the path of said linearly polarized light beam and adapted for transmitting said light beam at first and second predetermined planes of polarization; and, means positioned with respect to said latter means for generating first and second electrical signals representative of the magnitude and direction of motion of the interference fringes.

Claim 5

In an interferometer for measuring distance: a light reflector means coupled to a movable object for movement therewith, said reflector means having reflective surfaces adapted for reversing the direction of propagation of a polarized impinging light beam along a path differing from an incident beam path and for reversing the direction of polarization thereof; a light beam splitter adapted for dividing an impinging light beam into transmitted and reflected components; light source means including a laser light source arranged for causing polarized light which is polarized in a first direction to impinge upon said beam splitter; a light beam combination means; said beam splitter positioned with respect to said reflector means and with respect to said light beam combination means for causing a transmitted light component to impinge upon said reflector means and for directing a reflected component from said first beam splitter to said light beam combination means whereby the transmitted and reflected beams are of substantially equal intensity; said light beam combination means positioned with respect to said first beam splitter and with respect to said reflector means for causing a combination of a reflected light component from said first beam splitter and a reflected light component from said reflector means and for providing a resultant linearly polarized light beaM having a plane of polarization rotatable in accordance with motion of the object; means disposed in the path of said linearly polarized light beam and adapted for transmitting said light beam at first and second predetermined planes of polarization; and, means positioned with respect to said latter means for generating first and second electrical signals representative of the magnitude and direction of motion of the interference fringes.

Claim 6

The interferometer of claim 3 wherein said light beam combination means comprises a second beam splitter and an optical retarding means.