Abstract

A 14-inch ruling engine, whose operation with interferometer control of grating blank position between ruling strokes has been described previously, is now being operated with continuous blank advance and control. Displacement of the carriage holding the grating blank is measured in terms of the phase of a fringe system of constant inclination passing across a photoelectric pickup, which produces low-frequency ac whose phase is compared with that from a generator measuring the phase of motion of the ruling diamond. Synchronism between diamond and blank is maintained through corrections fed into a differential on the engine screw-worm by a balancing motor operated by phase differences. Grooves straight to one-tenth fringe, up to 9 in. long, can be produced by means of a cam-and-lever system which rectifies the otherwise simple harmonic motion of the diamond carriage. Continuous servo control results in improved elimination of screw errors and engine vibrations, and in simplified circuitry. The needed electronic and interferometric control systems have been found to function reliably over the long periods needed to rule large gratings.

A change-gear system permits passage of any desired fractional number of fringes per diamond stroke needed to produce from about 50 000 to 2000 grooves per inch. The signal-to-noise ratio obtained when green light from an Hg-198 tube is used to illuminate the carriage-translation interferometer is found to permit control over 10 in. of carriage motion, and stepping methods are being studied to permit multiplication of this distance. Plane gratings up to 8 in. in width of ruling and 5 in. in groove length have been produced, which show acceptably low ghost intensities despite original screw errors of more than 50 times the tolerance limit. Error-of-run and fanning appear to be under good control over distances of 8 in. Rapidly occurring random errors previously found have been traced to lateral motion of the diamond carriage and eliminated. Slow irregularities in groove position are ascribed to temperature variations, to which the engine has been found to be 10 times as sensitive as necessary; these are now being removed. Continuous oscilloscope records taken during ruling show that blank positioning is being controlled by servo interferometry to within 1/40 fringe or better, and indicate sources of disturbances whose removal should result in further improvement.

© 1955 Optical Society of America

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References

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  1. G. R. Harrison and J. E. Archer, J. Opt. Soc. Am. 41, 495 (1951).
    [Crossref]
  2. G. R. Harrison, Physics Today 3, 6 (1950).
    [Crossref]
  3. G. R. Harrison and W. H. Culver, J. Opt. Soc. Am. 41, 870 (1951).
    [Crossref]
  4. Harrison, Stroke, and Klippenberg, J. Opt. Soc. Am. 44, 347 (1954).
  5. A. A. Michelson, Astrophys. J. 18, 278 (1903); Harrison, Davis, and Robertson, J. Opt. Soc. Am. 43, 858 (1953).
    [Crossref]
  6. W. E. Williams (private communication, 1947), E. R. Peck, J. Opt. Soc. Am. 38, 66 and 1015 (1948), and others, have suggested the use of corner-cube reflectors to minimize rotational effects in interferometers. However, here we wish to detect them if present.
    [Crossref]
  7. M. Francon, Rev. opt. 26, 434 (1947).
  8. W. F. Meggers and F. O. Westfall, J. Research Natl. Bur. Standards 44, 447 (1950); W. F. Meggers and K. G. Kessler, J. Opt. Soc. Am. 40, 737 (1950).
    [Crossref]
  9. G. R. Harrison, J. Opt. Soc. Am. 39, 422 (1949).
  10. H. D. Babcock and H. W. Babcock, J. Opt. Soc. Am. 41, 776 (1951).
    [Crossref]
  11. G. R. Harrison, J. Opt. Soc. Am. 39, 413 (1949).
    [Crossref]
  12. H. D. Babcock and H. W. Babcock, J. Opt. Soc. Am. 41, 779 (1951).
    [Crossref]
  13. John Strong, J. Opt. Soc. Am.41, 3 (1951) and personal communication.
    [Crossref]
  14. G. W. Stroke, J. Opt. Soc. Am. 44, 347 (1954) and J. Opt. Soc. Am. 45, 30 (1955); L. A. Sayce, Endeavour, 210 (October, 1953).

1954 (2)

Harrison, Stroke, and Klippenberg, J. Opt. Soc. Am. 44, 347 (1954).

G. W. Stroke, J. Opt. Soc. Am. 44, 347 (1954) and J. Opt. Soc. Am. 45, 30 (1955); L. A. Sayce, Endeavour, 210 (October, 1953).

1951 (4)

H. D. Babcock and H. W. Babcock, J. Opt. Soc. Am. 41, 779 (1951).
[Crossref]

H. D. Babcock and H. W. Babcock, J. Opt. Soc. Am. 41, 776 (1951).
[Crossref]

G. R. Harrison and J. E. Archer, J. Opt. Soc. Am. 41, 495 (1951).
[Crossref]

G. R. Harrison and W. H. Culver, J. Opt. Soc. Am. 41, 870 (1951).
[Crossref]

1950 (2)

W. F. Meggers and F. O. Westfall, J. Research Natl. Bur. Standards 44, 447 (1950); W. F. Meggers and K. G. Kessler, J. Opt. Soc. Am. 40, 737 (1950).
[Crossref]

G. R. Harrison, Physics Today 3, 6 (1950).
[Crossref]

1949 (2)

G. R. Harrison, J. Opt. Soc. Am. 39, 422 (1949).

G. R. Harrison, J. Opt. Soc. Am. 39, 413 (1949).
[Crossref]

1947 (1)

M. Francon, Rev. opt. 26, 434 (1947).

1903 (1)

A. A. Michelson, Astrophys. J. 18, 278 (1903); Harrison, Davis, and Robertson, J. Opt. Soc. Am. 43, 858 (1953).
[Crossref]

Archer, J. E.

Babcock, H. D.

H. D. Babcock and H. W. Babcock, J. Opt. Soc. Am. 41, 776 (1951).
[Crossref]

H. D. Babcock and H. W. Babcock, J. Opt. Soc. Am. 41, 779 (1951).
[Crossref]

Babcock, H. W.

H. D. Babcock and H. W. Babcock, J. Opt. Soc. Am. 41, 779 (1951).
[Crossref]

H. D. Babcock and H. W. Babcock, J. Opt. Soc. Am. 41, 776 (1951).
[Crossref]

Culver, W. H.

G. R. Harrison and W. H. Culver, J. Opt. Soc. Am. 41, 870 (1951).
[Crossref]

Francon, M.

M. Francon, Rev. opt. 26, 434 (1947).

Harrison,

Harrison, Stroke, and Klippenberg, J. Opt. Soc. Am. 44, 347 (1954).

Harrison, G. R.

G. R. Harrison and J. E. Archer, J. Opt. Soc. Am. 41, 495 (1951).
[Crossref]

G. R. Harrison and W. H. Culver, J. Opt. Soc. Am. 41, 870 (1951).
[Crossref]

G. R. Harrison, Physics Today 3, 6 (1950).
[Crossref]

G. R. Harrison, J. Opt. Soc. Am. 39, 413 (1949).
[Crossref]

G. R. Harrison, J. Opt. Soc. Am. 39, 422 (1949).

Klippenberg,

Harrison, Stroke, and Klippenberg, J. Opt. Soc. Am. 44, 347 (1954).

Meggers, W. F.

W. F. Meggers and F. O. Westfall, J. Research Natl. Bur. Standards 44, 447 (1950); W. F. Meggers and K. G. Kessler, J. Opt. Soc. Am. 40, 737 (1950).
[Crossref]

Michelson, A. A.

A. A. Michelson, Astrophys. J. 18, 278 (1903); Harrison, Davis, and Robertson, J. Opt. Soc. Am. 43, 858 (1953).
[Crossref]

Stroke,

Harrison, Stroke, and Klippenberg, J. Opt. Soc. Am. 44, 347 (1954).

Stroke, G. W.

G. W. Stroke, J. Opt. Soc. Am. 44, 347 (1954) and J. Opt. Soc. Am. 45, 30 (1955); L. A. Sayce, Endeavour, 210 (October, 1953).

Strong, John

John Strong, J. Opt. Soc. Am.41, 3 (1951) and personal communication.
[Crossref]

Westfall, F. O.

W. F. Meggers and F. O. Westfall, J. Research Natl. Bur. Standards 44, 447 (1950); W. F. Meggers and K. G. Kessler, J. Opt. Soc. Am. 40, 737 (1950).
[Crossref]

Williams, W. E.

W. E. Williams (private communication, 1947), E. R. Peck, J. Opt. Soc. Am. 38, 66 and 1015 (1948), and others, have suggested the use of corner-cube reflectors to minimize rotational effects in interferometers. However, here we wish to detect them if present.
[Crossref]

Astrophys. J. (1)

A. A. Michelson, Astrophys. J. 18, 278 (1903); Harrison, Davis, and Robertson, J. Opt. Soc. Am. 43, 858 (1953).
[Crossref]

J. Opt. Soc. Am. (8)

G. R. Harrison and J. E. Archer, J. Opt. Soc. Am. 41, 495 (1951).
[Crossref]

G. R. Harrison and W. H. Culver, J. Opt. Soc. Am. 41, 870 (1951).
[Crossref]

Harrison, Stroke, and Klippenberg, J. Opt. Soc. Am. 44, 347 (1954).

G. R. Harrison, J. Opt. Soc. Am. 39, 422 (1949).

H. D. Babcock and H. W. Babcock, J. Opt. Soc. Am. 41, 776 (1951).
[Crossref]

G. R. Harrison, J. Opt. Soc. Am. 39, 413 (1949).
[Crossref]

H. D. Babcock and H. W. Babcock, J. Opt. Soc. Am. 41, 779 (1951).
[Crossref]

G. W. Stroke, J. Opt. Soc. Am. 44, 347 (1954) and J. Opt. Soc. Am. 45, 30 (1955); L. A. Sayce, Endeavour, 210 (October, 1953).

J. Research Natl. Bur. Standards (1)

W. F. Meggers and F. O. Westfall, J. Research Natl. Bur. Standards 44, 447 (1950); W. F. Meggers and K. G. Kessler, J. Opt. Soc. Am. 40, 737 (1950).
[Crossref]

Physics Today (1)

G. R. Harrison, Physics Today 3, 6 (1950).
[Crossref]

Rev. opt. (1)

M. Francon, Rev. opt. 26, 434 (1947).

Other (2)

W. E. Williams (private communication, 1947), E. R. Peck, J. Opt. Soc. Am. 38, 66 and 1015 (1948), and others, have suggested the use of corner-cube reflectors to minimize rotational effects in interferometers. However, here we wish to detect them if present.
[Crossref]

John Strong, J. Opt. Soc. Am.41, 3 (1951) and personal communication.
[Crossref]

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Figures (10)

Fig. 1
Fig. 1

View of the ruling engine with cover removed and oil level lowered. Power, electronic, and optical control units are housed in an anteroom behind right-hand wall.

Fig. 2
Fig. 2

Block diagram of the electronic system for fringe control of groove spacing with continuous blank motion.

Fig. 3
Fig. 3

Oscillograph records of residual voltage differences between the blank-positioning fringe signal and the diamond-positioning generator signal during ruling. In the upper record the residual instantaneous error during correction is held to 1/35 fringe, and the actual error in groove position to considerably less. The increased error with diamond carriage on was reduced to values below those shown in the upper record by using a compensator to reduce engine rocking, and by lightening the diamond carriage.

Fig. 4
Fig. 4

Strain-gauge records showing the amplitude of engine rocking when various loadings were applied to the compensator. About 1/30 of this amplitude appeared as relative motion of blank carriage and reference mirror.

Fig. 5
Fig. 5

Diagrams showing variation of signal modulation intensity with angular size and positioning of source hole.

Fig. 6
Fig. 6

Variation of fringe signal modulation with interferometer mirror separation for three sets of mirror adjustments.

Fig. 7
Fig. 7

New monorail mounting of the diamond carriage, in which linear shape of groove is controlled largely by an optical flat F, against which a shoe S on the diamond carriage slides. The diamond is suspended directly from graphitar cylinders G which slide along monorail N. The rod which moves the diamond carriage pushes against ring R, so that accidental torques are not transmitted to the diamond carriage.

Fig. 8
Fig. 8

Portions of records of fringes showing lateral motion of the diamond carriage and diamond. Records a and b were taken with the old monorail suspension, and show shifts due to rolling balls. Records c and d were taken with the new mounting.

Fig. 9
Fig. 9

The rectification linkage use to convert SHM from the bell crank to uniform linear motion of the diamond. The two outside levers are hinged at the floor, while the center lever, hinged at the top, serves to give adjustable amplitude to the motion of the push-rods at lower right. The horizontal rod at upper right operates the compensator in opposite phase to that of the push-rods. The fixed correction cam is seen at center left.

Fig. 10
Fig. 10

Test fringes from various gratings, a. Fuzzy and irregular fringes obtained from gratings produced with the old servo and diamond carriage systems. b. Improved fringes resulting from better servo response and elimination of random diamond shifts, but still showing some irregularities. These are now believed to originate from undue temperature sensitivity arising from improper interferometer mounting. c. Fringes showing shifts at y and z produced by introducing deliberate phase discontinuities that can be controlled to 1/100 fringe.

Equations (6)

Equations on this page are rendered with MathJax. Learn more.

I = 4 a 2 cos 2 ϕ 2 .
E = 16 π a 2 0 R s cos 2 ( ϕ 2 ) R d R ,
ϕ = ( ϕ 0 - ϕ α ) 2 π e λ ( α 2 2 )
ρ s = α 1 min 2 = 0.7 α 1 max 2 ,
s = 0.7 α 1 max ,
D s = 1.82 mm .