Interferometric measuring system

Claim 2

In an interferometer having a laser light source; a prismatic element in the form of a single integrated unit having a single partially light transmissive beam splitter adapted to divide a light beam from said laser light source Into two split beams respectively comprising a fixed length reference beam and a variable length measuring beam; means for defining a variable length measuring beam pathway comprising a relatively movable trihedral prism adapted to receive the measuring beam from said beam splitter and being adapted to reflectively return a spaced apart parallel beam toward said prismatic element; a reflector fixedly carried by said prismatic element positioned to receive said measuring beam returned by said trihedral prism and reflectively direct the returned beam toward said single beam splitter for recombining with said reference beam to produce interference fringe patterns; detector means responsive to the fringe patterns resulting from said recombined reference and measuring beams for indicating the extent of relative movement between said trihedral prism and said prismatic element; and means for effecting relative movement between said trihedral prism and said prismatic element.

Claim 3

In an interferometer having a light source adapted to project a monochromatic coherent beam of light; a single unitary prismatic element having a semi-transparent and partially reflective beam splitter adapted to reflect one-half of the light beam transversely from said source as a fixed length reference beam and to transmit one-half of the light beam from said light source to constitute a variable length measuring beam; a prismatic reflector carried for movement relative to said prismatic element along a path parallel to the one-half light beam transmitted by said beam splitter; plural reflectors carried by said prismatic reflector in position to receive the one-half light beam, reflect the received beam laterally a spaced distance and reflect the laterally reflected beam toward first prismatic element for returning the one-half measuring light beam to said prismatic element in spaced parallel relationship to the original one-half light beam transmitted therefrom; another reflector fixedly carried by said prismatic element in position to receive the returned one-half light beam from said prismatic reflector and being operative to reflect the returned beam toward said beam splitter for recombining with the other one-half of the light beam reflected therefrom to produce interference fringe patterns; a light sensitive measuring system responsive to the interference fringes operative to indicate the extent of relative movement between said prismatic element and said prismatic reflector; and, power drive means connected to effect relative movement between said prismatic element and said prismatic reflector.

Claim 4

In an interferometer having a light source adapted to project a monochromatic coherent beam of light; a single unitary prismatic element having a semi-transparent and partially reflective beam splitter adapted to reflect one-half of the light beam transversely from said source as a fixed length reference beam and to transmit one-half of the light beam from said light source to constitute a variable length measuring beam; a prismatic reflector carried for movement relative to said prismatic element along a path parallel to the one-half light beam transmitted by said beam splitter; plural reflectors carried by said prismatic reflector in position to receive the one-half light beam, reflect the received beam laterally a spaced distance and reflect the laterally reflected beam toward first prismatic element for returning the one-half measuring light beam to said prismatic element in spaced parallel relationship to the original one-half light beam transmitted therefrom; another reflector fixedly carried by said prismatic element in position to receive the returned one-half light beam from said prismatic reflector and being operative to reflect the returned beam toward said beam splitter for recombining with the other one-half of the light beam reflected therefrom to produce interference fringe patterns; a light sensitive measuring system responsive to the interference fringes operative to indicate the extent of relative movement between said prismatic element and said prismatic reflector; and, power drive means connected to effect relative movement between said prismatic element and said prismatic reflector.

Claim 5

In an interferometric measuring system; a laser light source adapted to project a coherent beam of monochromatic light; a single unitary prismatic element carried in fixed relationship to said laser light source and having a single beam splitter adapted to divide a projected beam therefrom into two split beams; a movable prismatic reflector for receiving one of the split light beams from said prismatic element and reflectively returning the received beam to said prismatic element along a spaced apart parallel pathway; a fixed reflector fixedly carried by said prismatic element in position to receive the beam reflectively returned from said movable prismatic reflector and adapted to reflect the returned beam toward said single beam splitter carried thereby to be recombined with the other of said split beams to produce interference fringe patterns for indicating the extent of relative movement between said prismatic reflector and said prismatic element; detector means connected to be actuated by said interference fringe patterns; and a power drive connected to effect relative movement between said prismatic reflector and said prismatic element.

Claim 6

In an interferometric measuring system; a laser light source adapted to project a coherent beam of monochromatic light; a single unitary prismatic element carried in fixed relationship to said laser light source and having a single beam splitter adapted to divide a projected beam therefrom into two split beams; a movable prismatic reflector for receiving one of the split light beams from said prismatic element and reflectively returning the received beam to said prismatic element along a spaced apart parallel pathway; a fixed reflector fixedly carried by said prismatic element in position to receive the beam reflectively returned from said movable prismatic reflector and adapted to reflect the returned beam toward said single beam splitter carried thereby to be recombined with the other of said split beams to produce interference fringe patterns for indicating the extent of relative movement between said prismatic reflector and said prismatic element; detector means connected to be actuated by said interference fringe patterns; and a power drive connected to effect relative movement between said prismatic reflector and said prismatic element.

Claim 7

In an interferometer provided with a single unitary prismatic element having a single beam splitter for splitting entrant light into two beams including a reference beam and a measuriNg beam; a relatively movable unitary prismatic reflector adapted to receive the measuring beam and reflectively return a spaced apart parallel beam toward said prismatic means; reflective means carried by said unitary prismatic element and being adapted to redirect the returned beam to said single beam splitter for recombining with said reference beam and to develop two separate sets of identical interference fringe patterns; means for effecting relative movement between said unitary prismatic element and said prismatic reflector; a pair of grated masks respectively interposed in the paths of the two interference fringe patterns and operable to modify the respective sets of fringe patterns one of said masks being offset from the other relative to said interference fringe patterns; and a light sensitive detector in the path of each modified fringe pattern from said masks to be actuated thereby for measuring the extent of movement and each being responsive to the leading or lagging relationship of the activation relative to the other detector caused by the offsetting of said masks to determine the direction of movement.

Claim 8

In an interferometer provided with a single unitary prismatic element having a single beam splitter for splitting entrant light into two beams including a reference beam and a measuriNg beam; a relatively movable unitary prismatic reflector adapted to receive the measuring beam and reflectively return a spaced apart parallel beam toward said prismatic means; reflective means carried by said unitary prismatic element and being adapted to redirect the returned beam to said single beam splitter for recombining with said reference beam and to develop two separate sets of identical interference fringe patterns; means for effecting relative movement between said unitary prismatic element and said prismatic reflector; a pair of grated masks respectively interposed in the paths of the two interference fringe patterns and operable to modify the respective sets of fringe patterns one of said masks being offset from the other relative to said interference fringe patterns; and a light sensitive detector in the path of each modified fringe pattern from said masks to be actuated thereby for measuring the extent of movement and each being responsive to the leading or lagging relationship of the activation relative to the other detector caused by the offsetting of said masks to determine the direction of movement.

Claim 9

In an interferometer having a measuring light beam and a reference light beam; a beam splitter adapted to receive said measuring and reference light beams for recombining to produce interference fringe patterns and produce two beams of identical fringe patterns respectively comprising alternating dark and light bands; a pair of apertured light masks respectively provided with parallel slotted apertures corresponding in width to the bands comprising said fringe patterns and the space between them being of the same width; adjusting means for supporting one of said masks in the paths of each of the interference fringe patterns from said beam splitter for predeterminately modifying said fringe patterns and for offsetting one of said masks from the other relative to said interference fringe patterns; a light sensitive detector in the path of each of said modified fringe pattern from said masks; and means for effecting relative movement between said reflector and said prismatic means and said light detectors are activated by said interference fringe pattern for measuring the extent of movement and being responsive to the leading or lagging relationship of the activation relative to the other caused by the offsetting of said masks for determining the direction of movement.

Claim 10

In an interferometer having a measuring light beam and a reference light beam; a beam splitter adapted to receive said measuring and reference light beams for recombining to produce interference fringe patterns and produce two beams of identical fringe patterns respectively comprising alternating dark and light bands; a pair of apertured light masks respectively provided with parallel slotted apertures corresponding in width to the bands comprising said fringe patterns and the space between them being of the same width; adjusting means for supporting one of said masks in the paths of each of the interference fringe patterns from said beam splitter for predeterminately modifying said fringe patterns and for offsetting one of said masks from the other relative to said interference fringe patterns; a light sensitive detector in the path of each of said modified fringe pattern from said masks; and means for effecting relative movement between said reflector and said prismatic means and said light detectors are activated by said interference fringe pattern for measuring the extent of movement and being responsive to the leading or lagging relationship of the activation relative to the other caused by the offsetting of said masks for determining the direction of movement.

Claim 11

In an interferometer comprising a base and a cooperating table carried by said base for relative rectilinear movement; a laser carried by said base adapted to project a collimated light beam toward said table and parallel to the rectilinear path of movement thereof; a unitary prismatic element having a single semi-transparent beam divider and being fixedly secured to said base in an angularly interposed beam intercepting position relative to the beam from said laser, said beam divider adapted to divide the entrant beam into two diverging split beams comprising a measuring beam projected outwardly toward said table along a path parallel to the path of movement thereof and a transversely directed fixed length reference beam; prismatic reflector means fixedly carried by said table in a position to receive the output beam from said beam divider and reflectively return a continuous spaced apart parallel measuring beam toward said unitary prismatic element; an angular reflector fixed to said unitary prismatic element for continuously reflecting the returned beam from said reflector means transversely toward said beam divider along a direction and path aligned with said divided fixed length reference beam from said laser for combining therewith to provide interference fringe patterns, said prismatic reflector means and said angular reflector providing a continuous unidirectional pathway for the variable length measuring beam; and, a light responsive counting device actuated by said interference fringe patterns for indicating tHe extent of relative movement between said table and said base.

Claim 12

In an interferometer comprising a base and a cooperating table carried by said base for relative rectilinear movement; a laser carried by said base adapted to project a collimated light beam toward said table and parallel to the rectilinear path of movement thereof; a unitary prismatic element having a single semi-transparent beam divider and being fixedly secured to said base in an angularly interposed beam intercepting position relative to the beam from said laser, said beam divider adapted to divide the entrant beam into two diverging split beams comprising a measuring beam projected outwardly toward said table along a path parallel to the path of movement thereof and a transversely directed fixed length reference beam; prismatic reflector means fixedly carried by said table in a position to receive the output beam from said beam divider and reflectively return a continuous spaced apart parallel measuring beam toward said unitary prismatic element; an angular reflector fixed to said unitary prismatic element for continuously reflecting the returned beam from said reflector means transversely toward said beam divider along a direction and path aligned with said divided fixed length reference beam from said laser for combining therewith to provide interference fringe patterns, said prismatic reflector means and said angular reflector providing a continuous unidirectional pathway for the variable length measuring beam; and, a light responsive counting device actuated by said interference fringe patterns for indicating tHe extent of relative movement between said table and said base.

Claim 13

An interferometer according to claim 6 including phase differentiating means fixedly interposed in the path of one of said two diverging split light beams that originate from said single beam divider in such a manner as to divide the associated one of said diverging beams into two phase differentiated beam portions and being operative to provide two corresponding phase differentiated portions in the interference fringe patterns of said recombined beams; and, said counting device comprising separate detector means carried by said frame and being respectively responsive to the phase differentiated interference fringe patterns in said recombined split beams for indicating the direction and extent of relative movement between said unitary prismatic element carried by said frame and said prismatic reflector carried by said relatively movable member.