`
`
`
`EXHIBIT
`
`EXHIBIT
`1001
`
`1001
`
`

`

`Jan. 5, 1971
`3,552,85 7
`F. HOCK ET AL
`OPTICAL DEVICE FOR THE DETERMINATION OF THE SPACING OF
`AN OBJECT AND ITS ANGULAR DEVIATION
`RELATIVE ']'0 AN INITIAL POSITION
`
`Filed April 19, 1966
`
`2 Sheets-Sheet 1
`
`OSCILLATORY
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`INVENTOR
`FROMUND HOCK, KARL LANG, HEHIBERT LOSS&:M
`BY
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`
`ATTOltNl::Y.
`
`

`

`Jan. 5, 1971
`3,552,85 7
`F. HOCK ET AL
`OPTICAL DEVICE FOR THE DETERMINATION OF THE SPACING OF
`AN OBJECT AND ITS ANGULAR DEVIATION
`RELATIVE TO AN INITIAL POSITION
`
`Filed April 19. 1966
`
`2 Sheets-Sheet 2
`
`16
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`
`BY
`
`INVENTORS
`Fromund Hock
`Karl Langa
`Heribert Luessem
`
`Mr-r- :;:a·z~
`
`

`

`United States Patent Office
`
`3,552,85'7
`Patented Jan. 5, 1971
`
`1
`
`3,552,857
`OPTICAL DEVICE FOR THE DETERMINATION OF
`·THE SPACING OF AN OBJECT AND ITS ANGU(cid:173)
`LAR DEVIATION RELATIVE TO AN INITIAL
`POSITION
`Fromund Hock, Wetzlar, Karl Lang, Atzbacb, Kreis
`Wetzlar, and HeribertLiissem, Braunfels, Kreis Wetz(cid:173)
`lar, Germany, assignors to Fa. Ernst Leitz GmbH
`Filed Apr. 19, i966, Ser. No. 543,576
`Claims priority, application Germany, Apr. 24, 1965,
`L 50,566
`Int. Cl. G01b 11/26; G01n 21/00
`U.S. Cl. 356-73
`
`12 Claims
`
`ABSTRACT OF THE DISCLOSURE
`A multi-purpose optical measuring device in which an
`image of an oscillating luminous scanning mark is pro(cid:173)
`jected, via a beam splitter and an objective lens, onto a
`reflecting surface of an object to be located, positioned,
`or measured, or onto a reflector rigidly connected thereto.
`The image of the scanning mark, after reflection from the
`object, is projected through the objective lens and the
`beam splitter onto an index· carrier having a plurality of
`indices. Said image coacts with said indices to produce
`optical signals which are indicative of any lateral or
`angular displacement of the object. An eyepiece and/ or
`a photoelectric transducer are positioned adjacent to the
`index carrier for evaluation of said signals.
`
`BACKGROUND OF THE INVENTION
`This invention relates to a multi-purpose optical meas(cid:173)
`uring device for determining the position or the move(cid:173)
`ment of an object relative to a reference point or a refer(cid:173)
`ence direction.
`There are a number of measuring devices which serve
`for the determination of the position of a reference mark
`placed on the object ·to be measured. These instruments
`make use of a beam of light which is caused to oscillate
`by means of a deflector and impinges on the mark to be
`located. The result is obtained by a comparison of the
`different times which elapse between the successive cross(cid:173)
`ings of the mark to be located during the oscillation. It
`is a disadvantage of these instruments that they can only
`be used when the object to be measured is provided with
`marks on its surface.
`SUMMARY OF THE INVENTION
`It is an object of the invention to provide a multi- 50
`purpose optical measuring instrument which, with minor
`alterations, can be used for: determination of the position
`or the movement of an object perpendicular to the instru(cid:173)
`ment's axis; determination of the angle of objects inclined
`to the instrument's axis; measurement of curvature and 55
`determination of the eccentricity of revolving shafts.
`Briefly; a device according to the present invention is a
`multi-purpose measuring and/ or control device for the
`visual and/or photoelectric determination of the position
`or motion of objects of measurement by means of refer- 60
`ence marks which either are placed outside of the instru(cid:173)
`ment or as index marks in the interior of same. It com(cid:173)
`prises at least one movable luminous scanning mark which
`is oscillated along a path of oscillation. According to the
`invention the light from this mark penetrates an optical 65
`system comprising at least one beam splitter and one
`objective. After mutual reaction with the object to be
`measured and reflection from same, the light passes
`through said objective and said beam splitter and impinges
`upon an index carrier the indices of which are grouped 70
`
`2
`in such a way that the optical axis penetrates the carrier
`between two adjacent indices. Means for the evaluation
`of the result of the measurement are placed adjacent to
`the index carrier on the side thereof remote from said
`5 beam splitter. Said evaluation means may comprise at
`least one more beam splitter. Numerous types of reflectors
`can be used as, or affixed to, the object of measurement,
`such as plane mirrors, reflectors comprising a plurality
`of planar reflecting elements all of which make the same
`10 angle with a common axis, and reflectors shaped like at
`least part of a surface which is symmetrical with respect
`to a plane. Examples of reflectors comprising a plurality
`of plane reflecting surfaces all of which make the same
`angle with a common axis are triple mirrors, cube corner
`15 prisms, and angular mirrors. Examples of reflectors which
`are shaped like at least part of a surface which is sym(cid:173)
`metrical with respect to a plane are cylindrical and spheri(cid:173)
`cal mirrors, toric mirrors, and convex spherical surfaces
`in combination with a refracting element the focal point
`20 of which lies on the mirror surface. According to another
`feature of the invention the scanning mark can consist of
`a luminous element which is not stimulated by heat (e.g.,
`an electroluminescent element or a semiconductor junc(cid:173)
`tion). The indices of the index carrier may comprise
`25 bodies exhibiting the outer or inner photoelectric effect
`(including phototransistors) and may respectively be pro(cid:173)
`vided with individual output electrodes in order to obtain
`individual output signals therefrom. By use of image
`splitting optical means in the area between the scanning
`30 mark and the index carrier a plurality of images of the
`scanning mark may be produced.
`In comparison to known devices the present invention
`has the advantage that only light which is absolutely
`necessary for the performance of the measurement is
`35 transmitted through the instrument, which favorably in(cid:173)
`fluences the signal-to-noise ratio in the evaluation means.
`Moreover, a particularly good contrast is obtained on
`account of the absence of scattered light rays. Additionally,
`it is possible to produce the image or the scanning mark
`40 at any place of the index carrier so that precise measuring
`means are only required to cover the distance between
`two adjacent indices of the index carrier whereas in re(cid:173)
`gard to the complete field of indices the accuracy only
`depends upon the precision of graduation of the index
`45 carrier. The manner in which the invention may be car(cid:173)
`ried out will now be explained with reference to the
`attached drawings by way of different forms of embodi(cid:173)
`ment.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`In the drawings:
`FIG. 1 shows an instrument according to the present
`invention in the form of a measuring microscope,
`FIG. la shows an instrument according to the present
`invention used to locate the graduations of a scale or to
`interpolate therebetween,
`FIG. 3a shows an instrument according to the present
`invention adapted to determine the angle between a re(cid:173)
`motely located reflector and the principal axis of the in(cid:173)
`strument,
`FIG. 4a shows an instrument according to the present
`invention with auxiliary photoelectric means for rapidly
`registering scale marks or spectral lines with the main
`axis of the measuring instrument,
`FIG. 2 shows additional embodiments of the reflector,
`FIG. 3 shows an instrument according to the present
`invention in the form of an autocollimator,
`FIG. 4 shows an embodiment of the invention for pro(cid:173)
`ducing the mean value of 2n indices.
`
`

`

`3
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`3,552,857
`
`In all of the illustrated embodiments, a light source 10
`in front of a condenser 11 illuminates a moving dia(cid:173)
`phragm 12 the slot 12a of which defines the scanning
`mark. The movement of the diaphragm may for example
`be oscillating or may consist of a pivoting movement
`around an axis parallel to the instrument axis in such a
`way that the scanning mark 12a remains constantly or
`intermittently in the path of light. The scanning light
`beam coming thus from the scanning mark 12a is di(cid:173)
`rected onto a reflector via the first beam splitter 13 and
`the objective 14. The light rays of the beam reflected
`from the reflector travel backward through the objective 15
`14 and are directed by beam splitter 13 onto the index
`carrier 16, provided with the indices 15. The image of
`the index plane of the carrier 16 is, via a second beam
`splitter 17, produced in an eyepiece 18 as well as on a
`photoelectric transducer 19. Beam splitter 17 can be a
`semi-silvered mirror, a conventional device for separat(cid:173)
`ing two polarized components or a dichroic device for
`splitting the beam as a function of wave length.
`FIG. 1 shows an embodiment in which an inclined
`semi-transparent plate 13 serves as the first beam splitter
`and a microscope objective 14 is used for an objective.
`It is advisable to choose the length of and locate the path
`of oscillation of the scanning mark 12a in such a way that
`the image of the scanning mark 12a on the index carrier
`16 remains between two adjacent indices 15 and has its
`center of oscillation halfway between them. A reflecting
`cylinder 26 with a generating line parallel to the scanning
`mark 12a is used for a reflector in this case. By moving
`the image of the scanning mark 12a across the surface of
`the cylinder a modulation of the reflected light rays reach(cid:173)
`ing index carrier 16 takes place because the light rays will
`not re-enter objective 14 when the image of scanning mark
`12a is produced on a portion of said cylinder remote from
`the highest element thereof. Deviations in the location of
`the cylinder from the instrument axis as defined by the
`center of oscillation of the scanning mark 12a and the
`lower principal point of the objective 14 are received
`photoelectrically and evaluated by an electronic device.
`The eyepiece 18 permits observation of a measurement
`or of an adjusting of the instrument. Means for the evalua(cid:173)
`tion of the signals produced by photosensitive element 19
`are known in the prior art and need not be described
`herein.
`FIG. la illustrates the use of the instrument of the in(cid:173)
`vention for precise determination of the position of a light(cid:173)
`absorbing graduation 21a on graduated scale 21 with re(cid:173)
`spect to the optical axis of the instrument. The location
`and length of the path of oscillation of scanning mark 12a
`is so chosen that the image of mark 12a on the mark car(cid:173)
`rier 16 remains between two marks 15. When the image
`of mark 12a passes over a graduation 21a the light re(cid:173)
`flected to mark carrier 16 is reduced. The electrical signal
`emitted by photoelectric cell 19 is evaluated by a well(cid:173)
`known means either for control purposes or to indicate
`the position of mark 21a on well-known indicating means.
`FIG. 3a shows the device of the invention in the form
`of a telescopic magnifier. The basic construction corre(cid:173)
`sponds to that of FIG. 3, but an optical system 40 is addi(cid:173)
`tionally inserted in this embodiment, a reflector being posi(cid:173)
`tioned in the focal plane thereof.
`FIG. 42 shows an instrument according to the inven(cid:173)
`tion in which a Wollaston prism 60 is inserted in the beam
`path and serves to produce two separate, differently polar(cid:173)
`ized images of mark 12a at an exposed spectrographic
`plate 62. An analyzer 63 assures that only one of these
`images will be sensed by the auxiliary photoelectric trans(cid:173)
`ducer 61. The output signals of this transducer may be
`used for the coarse positioning of plate 62, so that the
`irregularly-spaced spectral lines thereon may successively
`be quickly brought into registration with the axis of the
`
`25
`
`4
`optical system, whereafter the more precise but slow-act(cid:173)
`ing measuring system comprising photoelectric transducer
`19 may locate these lines with greater precision. Thus,
`there may be provided according to the invention a fast(cid:173)
`acting, high-precision analyzer for spectrographic plates
`5 and the like.
`FIG. 2 shows additional embodiments of the reflector.
`The reflector 22, for instance, consists of a carrier 22b
`which is provided with groove-like marks 22a. Their re-
`10 fleeting planks are inclined in such a way that the light
`reflected from them cannot re-enter the aperture of the
`objective 14. Return of the light rays into the aperture is
`only possible if the rays impinge upon the reflecting area
`surrounding the grooves.
`Another embodiment of the reflector is designated in
`FIG. 2 by the numeral 23. This reflector 23 is covered by
`a transparent index carrier 23a bearing light-absorbing
`marks 23b. In this case the modulation of the light com(cid:173)
`ing from the scanning mark 12a is caused by the marks
`20 23b which are located in the image plane of the objective
`14. The light within the field of the objective which during
`the scanning bypasses one of the indices 23b will be re(cid:173)
`flected by the reflector into the objective aperture.
`A concave mirror 24 also shown in FIG. 2 may be used
`to advantage if a work piece has no marks whatsoever
`and displacements of said work piece ia a plane are to
`be checked upon. The reflector 24 together with a refract(cid:173)
`ing optical element 24a has telecentric qualities. The con(cid:173)
`cave mirror 24 is placed upon the work piece and in case
`30 of displacements of this work piece from the optical axis
`of the instrument mirror 24 produces a double deviation
`of the image of scanning mark 12a on the index carrier
`16 owing to the 1 : 1 image forming quality of the concave
`mirror. If the reflector is, for instance, placed on the face
`35 place of a revolving shaft the eccentricity in one direction
`of the shaft may be measured and can be fed into a con(cid:173)
`trol loop not shown.
`The concave mirror is placed upon the work piece in
`such a way that the scanning mark 12a is imaged by the
`40 concave mirror in the ratio 1: 1. If the optical axis of the
`concave mirror coincides with the optical axis of the in(cid:173)
`strument the image of the scanning mark 12a is repro(cid:173)
`duced in itself and impinges after reflection from the
`beam splitter 13 upon the spot on the index carrier 16
`45 which corresponds to the zero position. If the concave
`mirror is moved in a lateral direction by a distance x
`the image produced by the concave mirror will move by
`a double distance 2x. This image of the scanning mark
`12a, enlarged by the objective 14, travels across the in-
`50 dices 15 in synchronism with the movement of the dia(cid:173)
`phragm 12. This causes the modulation of the light flux
`which contains the result of the measurement.
`If greater displacements of the work piece are to be
`measured a 90° roof or cube corner prism 25 may be
`55 used, especially instead of a non-telecentric concave mirror
`system. The roof edge of the prism should be maintained
`perpendicular to direction of the movement, perpendicular
`to the optical axis of the instrument, and parallel to the
`scanning mark. It should also be located in the plane of
`60 the image of the scanning mark 12a as produced by the
`objective 14.
`The image of the scanning mark 12a is always pro(cid:173)
`duced in the plane of symmetry of the edge of the
`reflector. In case this edge does not coincide with the
`65 optical axis of the instrument, the image of the scanning
`mark .12a will still appear in the symmetrical plane of
`the reflector. Thus, if the principal ray of the image
`forming beam enters at a distance y from the plane of
`symmetry, the diverging beam of light after focusing
`70 leaves the reflector in such a way that now the principal
`ray of this light beam runs parallel to the impinging
`principal ray at a distance 2y from the latter. This causes
`the image virtually to move laterally with double velocity.
`In place of the reflectors hitherto mentioned, convex
`75 mirrors may also be used to advantage, if their center
`
`

`

`3,552,857
`
`15
`
`25
`
`5
`of curvature lies in the image plane of the scanning
`mark 12a. Here the convex mirror may simultaneously
`perform. the function of a mechanical feeler-ball.
`The objective 34 as shown in FIG. 3 represents a tele(cid:173)
`scope objective. As a reflector, a fiat autocollimation
`mirror 35 is used and the indices on the carrier 16 cor(cid:173)
`respond to different angles. The functioning as an auto(cid:173)
`collimation telescope of ·the so designed instrument is
`similar to what has been explained above. If this instru(cid:173)
`ment is to be used as a refractometer the mirror has to
`be connected rigidly with the instrument at such a dis(cid:173)
`tance that between the instrument itself and the mirror
`at least one prismatic cell can be inserted. Instead of
`the rigidly mounted mirror the rear wall of the cell may
`be used as reflector if coated with a reflecting layer.
`FIG. 4 shows how a measurement may be performed
`averaging the positions of several indices provided on
`the reflector. Into the path of the light a Wollaston(cid:173)
`prism 50 is introduced that splits the light beam in two
`parts. If a division of the original light rays into a greater 20
`number of parts is desired more Wollaston-prisms have
`to be introduced together with circular polarizing quarter(cid:173)
`wave plates or optically active plates which cause a 45 o
`delineation. Examples of these are quartz plates 51 and
`53.
`If only one Wollaston-prism is used, two images of
`the scanning mark 12a in synchronous movement are
`obtained, the separation of which is governed by the
`focal length of the objective 14 and the splitting angle
`of the prism. The two images are polarized per:pendicu- 30
`larly to each other. Owing to this fact the two image
`producing light :fluxes are separable and distinguishable
`from each other. By means of two photoelectric trans(cid:173)
`ducers a control signal may be obtained in addition to
`the measuring signal.
`It is advisable to provide means by which the ampli(cid:173)
`tude and/or number of oscillations per time unit of
`ilie scanning mark may be varied. This means is shown
`~:Jchematically in FIG. 1. It is thus possible to control
`\the amplitude and/or the number of oscillations per
`time unit or to control them as a function of a signal
`obtained from the photosensitive element 19.
`It is also possible to form the indices 15 on the car-
`rier 16 differently from each other, for instance cor(cid:173)
`responding to a code, so that each scanned index simul(cid:173)
`taneously indicates its value. Also the indices 15 can
`themselves be photosensitive elements so that each illu(cid:173)
`minated index is marked by a change of its electric
`properties.
`.
`Another variation in the design of the herem de(cid:173)
`scribed multi-purpose measuring
`instrument can be
`achieve by using a self-luminous element in the place
`of the diaphragm 12, for instance a semi-conductor
`with light emitting junctions which moves in the same
`way as the diaphragm. In this case the light source 10
`as well as the condenser 11 can be dispensed with and
`the light intensity can be modulated easily by a higher
`frequency.
`As shown in FIGS. 1 and 3, additional optical means
`may be provided in order to afford additional illumina(cid:173)
`tion of the plane of the index carrier 16. As shown in
`FIG. 1, a concave mirror 70 may be mounted in line
`with the optical axis of the beam splitter 17, but on the
`opposite side of beam splitter 13. This concave mirror
`reflects one part of the rays which are deflected laterally
`from the first beam splitter 13 onto the index carrier 16
`via said beam splitter 13. By insertion of a filter 71 it
`:p1ay be insured that this additional illumination has no
`effect on the photoelectric transducer. Slide 72
`is
`marked with additional auxiliary indices or numerals, 70
`for instance indices of tolerance, which are projected
`onto carrier 16. These additional marks may also be
`movable relative to the image of scanning mark 12a
`for measuring purposes.
`This additional illumination, however, may also be 75
`
`6
`\achieved by providing an additional light source as
`shown in dotted lines in FIG. 4. Another possibility of
`additionally illuminating the index carrier 16 consists
`of optical means, as for instance mirrors, lenses or light
`5 guiding means by which the unutilized rays from light
`source 10 are used for this additional illumination.
`What we claim is:
`1. An optical measuring device for determining the
`distance and angular deviation of an object from an
`10 initial position comprising:
`a light source;
`means masking the light from the source to produce at
`least one luminous hair-like scanning mark;
`means for oscillating the mark producing means in
`a direction perpendicular to the path of light emanat(cid:173)
`ing from the source;
`light reflecting means mounted to the object for modu-
`lating incident light in response to object displace(cid:173)
`ment, the reflecting means being positioned in spaced
`relation to the mark producing means so that the
`scanning mark is incident thereon;
`beam splitting means positioned in the light return
`path of the reflecting means for producing a second
`path of reflection;
`a photosensitive transducer positioned in optical com(cid:173)
`munication with the second reflection path for de(cid:173)
`tecting changes in reflected light proportional to
`object displacement;
`and an index carrier provided with index marks posi(cid:173)
`tioned in the second reflection path, the marks be(cid:173)
`ing employed to restrict arcuate sweep of the second
`ref.lection path between predetermined marks.
`2. The apparatus of claim 1, together with visual means
`optically communicating with the index carrier for visu-
`35 ally evaluating object displacement.
`3. The apparatus of claim 2, together with a second
`beam splitting means optically positioned in parallel with
`the photosensitive transducer and the visual means for
`40 directing optical signals to both from the index carrier.
`4. A device as set forth in claim 1, at least some of
`said index marks including photosensitive elements, for
`generating associated electrical output signals.
`5. A multi-purpose optical measuring device as set
`forth in claim 1, including n beam splitting and polarizing
`45 means and n-1 circular polarizing or depolarizing op(cid:173)
`tically active means producing 2n images of said scanning
`mark on said reflecting means.
`'6. A device as set forth in claim 1, including means
`for additionally illuminating said index carrier, said re-
`50 fleeting means being a spherical mirror.
`7. A device as set forth in claim ·6, including filter
`means in the light ray path of the additional illumination.
`8. A device as set forth in claim 7, said means for
`additionally illuminating including image forming aux-
`55 iliary optical means to project additional auxiliary marks,
`said auxiliary marks being measurably movable and ex(cid:173)
`changeable.
`9. A multi-purpose optical device as set forth in claim
`2, together with polarizing means for allowing only rays
`60 polarized in one direction to reach said transducer.
`10. A multi-pur:pose optical measuring device as set
`forth in claim 3, said second beam splitter means being
`dichroid and separating said optical signals into two
`65 spectrally distinct parts, one of which is transmitted to
`the photosensitive means.
`11. A device as in claim 1, said object including a
`reflector having non-reflecting index marks spaced on its
`reflecting surface.
`12. A multi-purpose optical measuring device as claimed
`in claim 1 in which said object comprises reflecting means
`including a plurality of planar reflecting surfaces all of
`which make the same angle with a common axis.
`
`(References on following page)
`
`

`

`7
`References Cited
`
`3,552,857
`
`8
`FOREIGN PATENTS
`684,435 12/1952 Great Britain --------- 88-14
`1,006,698
`'10/1965 Great Britain
`88~14
`
`UNITED STATES PATENTS
`9/1961 Gievers -------------- 88-14
`2,998,746
`3,106,127 10/1963 Koller --------------- 88-24 5
`3,3,17,739
`5/1967 Larraburn et a!. _____ 250-232
`7 I 1967 Heinecke et al. ______ 250-232
`3,331,964
`3,381,570
`5/1968 Anway et al. --------- 88-14
`
`·RONALD L. WIBERT, Primary Examiner.
`J. ROTHENBERG, Assistant Examiner
`
`U.S.Cl.X.R.
`250-237;356-118, 138,152,172
`
`