Interferometer

Claim 3

The method as set forth in claim 1 wherein said step of directing a first beam of energy includes the step of causing said first beam of energy to be divergent when it encounters said first reflective surface, and said step of directing a second beam of energy includes the step of causing said second beam of energy to be divergent when it encounters said second reflective surface.

Claim 4

The method as set forth in claim 2 wherein said step of causing said first beam of energy to be divergent includes the step of causing said first beam of energy to have a spherical wavefront, and said step of causing said second beam of energy to be divergent includes the step of causing said second beam of energy to have a spherical wavefront.

Claim 5

The method as set forth in claim 3 wherein said first and second beams of energy are comprised of coherent light.

Claim 6

The method as set forth in claim 4 further including the step of positioning a member in accordance with the detected changes in the interference pattern.

Claim 7

The method as set forth in claim 5 wherein said step of positioning includes the positioning of a machine tool in accordance with the detected changes in the interference pattern.

Claim 8

Interferometric mensuration apparatus for measuring displacement of a body along an axis comprising: a. a body located on said axis and having first and second reflecting surfaces positioned along said axis and transverse thereto, said first and second reflecting surfaces being similarly shaped geometrically; b. means for directing a first beam of energy at said first reflecting surface including means for causing said first beam of energy to be divergent about said axis when it encounters said surface and reflects therefrom to form a first beam of reflected energy; c. means for directing a second beam of energy, coherent with respect to said first beam, at said second reflecting surface including means for causing said second beam of energy to be divergent about said axis when it encounters said second reflecting surface and reflects therefrom to form a second beam of reflected energy; d. means for causing said first and second reflected beams of energy to interfere to form an interference pattern; and e. means for measuring displacement of said body along said axis including detecting means for detecting changes in the interference pattern caused by said first and second reflected beams of energy and for rendering output signals indicative thereof, said output signals being representative of displacement of said body along said axis.

Claim 9

Interferometric mensuration apparatus for measuring displacement of a body along an axis comprising: a. a body located on said axis and having first and second reflecting surfaces positioned along said axis and transverse thereto, said first and second reflecting surfaces being similarly shaped geometrically; b. means for directing a first beam of energy at said first reflecting surface including means for causing said first beam of energy to be divergent about said axis when it encounters said surface and reflects therefrom to form a first beam of reflected energy; c. means for directing a second beam of energy, coherent with respect to said first beam, at said second reflecting surface including means for causing said second beam of energy to be divergent about said axis when it encounters said second reflecting surface and reflects therefrom to form a second beam of reflected energy; d. means for causing said first and second reflected beams of energy to interfere to form an interference pattern; and e. means for measuring displacement of said body along said axis including detecting means for detecting changes in the interference pattern caused by said first and second reflected beams of energy and for rendering output signals indicative thereof, said output signals being representative of displacement of said body along said axis.

Claim 10

Apparatus as set forth in claim 7 wherein said first and second reflecting surfaces are planar and substantially parallel.

Claim 11

Apparatus as set forth in claim 7 wherein said means for causing said first beam of energy to be divergent includes means for causing said first beam of energy to have a spherical wavefront when it encounters said first reflecting surface, and said means for causing said second beam of energy to be divergent includes means for causing said second beam of energy to have a spherical wavefront when it encounters said second reflecting surface.

Claim 12

Apparatus as set forth in claim 9 wherein said first and second reflecting surfaces are planar and substantially parallel.

Claim 13

Apparatus as set forth in claim 7 wherein said detecting means includes means for detecting only that portion of the interference pattern formed by substantially perpendicular reflection of said first and second reflected energy beams respectively from said first and second reflecting surfaces.

Claim 14

Apparatus as set forth in claim 11 wherein said means for causing said first beam of energy to be divergent includes means for causing said first beam of energy to have a spherical wavefront when it encounters said first reflecting surface, and said means for causing said second beam of energy to be divergent includes means for causing said second beam of energy to have a spherical wavefront when it encounters said second reflecting surface.

Claim 15

Apparatus as set forth in claim 12 wherein said first and second beams of energy are coherent light beams.

Claim 16

Apparatus as set forth in claim 13 wherein said first and second light beams emanate from a common light source.

Claim 17

Apparatus as set forth in claim 14 wherein said light beams are coherent and similarly polarized, and means are provided for varying the phase of a first polarization component of said first beam of light with respect to a second polarization component of said first beam of light, and wherein said detecting means includes first means for detecting the interference pattern formed by the first polarization components of said first and second beams, and second means for detecting the interference pattern formed by the second polarization components of said first and second beams.

Claim 18

Apparatus as set forth in claim 12 including: a. said body having third and fourth reflecting surfaces positioned along a second axis which is substantially perpendicular to said axis, said third and fourth reflecting surfaces being similarly shaped geometrically; b. means for directing a third beam of energy at said third reflecting surface including means for causing said third beam of energy to have a spherical wavefront when it encounters said surface and reflects therefrom to form a third beam of reflected energy; c. means for directing a fourth beam of energy at said fourth reflecting surface including means for causing said fourth beam of energy to have a spherical wavefront when it encounters said fourth reflecting surface and reflects therefrom to form a fourth beam of reflected energy; d. means for causing said third and fourth reflected beams of energy to interfere to form an interference pattern; and e. second detecting means for only detecting changes in the interference pattern formed by substantially perpendicular reflection of said third and fourth reflected beams of energy and for rendering an output signal indicative thereof, said output signal being indicative of displacement of said body along said second axis.

Claim 19

Apparatus as Set forth in claim 12 wherein means are provided for positioning a member in accordance with the output signal from said detecting means.

Claim 20

Apparatus as set forth in claim 17 wherein said positioning means includes a machine tool.

Claim 21

Apparatus as set forth in claim 12 wherein said apparatus includes a stationary reticle positioned on said axis, whereby displacement of said body relative to said reticle between first and second points on said body is measured by positioning said first point at said reticle, then positioning said second point at said reticle, and said detecting means detects changes in said interference pattern caused by movement of said body relative to said reticle.

Claim 22

Apparatus as set forth in claim 19 wherein: a. said first and second beams of light emanate from a common light source; and b. said reticle is positioned on said axis at a position where said first and second beams of light would have to travel an equal distance from said common light source to arrive at said reticle.

Claim 23

Apparatus as set forth in claim 14 wherein said first and second beams of light are formed by: a. source means for producing one beam of light having a spherical wavefront; b. beam splitter means positioned adjacent said source means to split said one beam of light into said first and second light beams; and c. mirror means positioned to direct said first and second beams of light against said first and second reflecting surfaces.

Claim 24

Apparatus as set forth in claim 21 wherein said detecting means includes: a. photodetecting means positioned adjacent to said beam splitter means; and b. a member having a small aperture therein positioned between said photodetecting means and said beam splitter means for examining only the interference pattern formed by substantially perpendicular reflection of said first and second reflected energy beams reflected respectively from said first and second reflecting surfaces.