`
`
`
`EXHIBIT
`
`EXHIBIT
`1007
`
`1007
`
`

`

`1!Q)Nmr,1lQ)W!!(!M!'I!BrE-S.~~H!ESENi!!~ Sj!R\'Ifllt,{!!_0M1Et;;!
`UNITED STATES DEPARTMENT OF COMMERCE
`United States Patent and Trademark Office
`
`February 04, 2013
`
`THIS IS TO CERTIFY THAT ANNEXED HERETO IS A TRUE COPY FROM
`THE RECORDS OF THIS OFFICE OF:
`
`U.S. PATENT: RE40,927
`ISSUE DATE: October 06,2009
`
`By Authority of the
`
`tual Property
`nd Trademark Office
`
`

`

`(19) United States
`c12) Reissued Patent
`Wild et al.
`
`1111111111111111111~111111111111111111111111111111111111111111111111111111
`
`USOORE40927E
`
`US RE40,927 E
`(IO) Patent Number:
`(45) Date of Reissued Patent:
`Oct. 6, 2009
`
`(54) OPTICAL DETECTION SYSTEM
`
`(75)
`
`Inventors: Norman R. Wild, Nashua, NH (US);
`Paul M. Leavy, Jr., Lynnfield, MA (US)
`
`(73) Assignee: BAE Systems Information and
`Electronic Systems Integration Inc.,
`Nashua, NH (US)
`
`(21) Appl. No.: 11/19'1,731
`
`(22) Filed:
`
`Aug.S, 2005
`
`Related U.S. Patent Documents
`
`Reissue of:
`(64) Patent No.:
`Issued:
`Appi.No.:
`Filed:
`
`(51)
`
`Int. Cl.
`B64D 1104
`GOIB 11126
`GOIJ 5102
`
`6,603,134
`Aug.S, 2003
`04/623,186
`Mar.10, 1967
`
`(2006.01)
`(2006.01)
`(2006.01)
`
`(52) U.S. Cl •......................... 250/526; 89/1.11; 250/342;
`356/141.1
`(58) Field of Classification Search .................. 250/526,
`250/342, 580, 493.1, 494.1, 495.1, 496.1;
`340/600, 619, 825.36, 892; 356/3,3.09, 124,
`356/127, 3.02; 359/528, 529, 626, 627; 89/1.11
`See application file for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`2,610,922 A
`9/1952
`2/1959
`2,873,381 A
`2,906,883 A
`9/1959
`2,970,310 A * 1/1961
`3,002,419 A
`10/1961
`3,020,792 A * 2/1962
`3,025,764 A
`3/1962
`
`Beck
`Lauroesch
`Hansen
`Edmond .................... 356/5.02
`Vyce
`Kingsbury ................. 88/1 UX
`McKenzie
`
`3,098,932 A * 7/1963 Laudon ..................... 250/83.3
`3,215,842 A * 11/1965 Thomas ...................... 398/170
`3,345,835 A
`10/1967 Nickell et al.
`3,405,025 A
`10/1968 Goldman
`3,443,072 A * 5/1969 Mori .......................... 235/454
`4,112,300 A " 9/1978 Hallet al.
`6,707,052 B1
`3/2004 Wild et al.
`
`OTHER PUBLICATIONS
`
`Francis Weston Sears, "Principles Of Physics Series,"
`Optics, Third Edition, Fifth printing, Addison-Wesley Pub(cid:173)
`lishing Company, Inc., Reading, MA, USA, Apr. 1958, pp.
`34-39 and 89-91.
`"Sheeting and Tape Reflective; Nonexposed Lens, Adhesive
`Backing," Federal Specification, FSC 9390, L-S-300, Sep.
`7,
`1965,
`pp.
`1-15, Superseding CCC-S-00320
`(Army-MO), Nov. 18, 1963, including the requirements of
`MILI-R-13689A, Jan. 10, 1956.
`(Retro-Reflective),"
`"Reflectorized Sheeting, Adhesive
`Military Specification, FSC 8305, MIL-R-13689A, Jan. 10,
`1956, Superseding MIL-R-13689 (CD), Oct. 4, 1954.
`Electronics, Nov. 10, 1961, pp.81-85.
`
`" cited by examiner
`
`Primary Examiner-Huy K Mai
`(74) Attorney, Agent, or Firm-Bingham McCutchen LLP;
`Robert C. Bertin; Daniel J. Long
`
`(57)
`
`ABSTRACT
`
`The present invention pertains to radiant energy systems and
`more particularly to systems exhibiting the retroreflection
`principle wherein the system comprises a focusing means
`and a surface exhibiting some degree of reflectivity posi(cid:173)
`tioned near the focal plane of the device, and wherein inci(cid:173)
`dent radiation falling within the field-of-view of said system
`is reflected back in a direction which is parallel to the inci(cid:173)
`dent radiation. The present invention has great applicability
`in military optical system applications for detecting the pres(cid:173)
`ence of an enemy employing surveillance equipment and for
`neutralizing this surveillance capability.
`
`70 Claims, 3 Drawing Sheets
`
`

`

`U.S. Patent
`
`Oct. 6, 2009
`
`Sheet 1 of3
`
`US RE40,927 E
`
`26,
`
`20
`
`24
`
`:R?))J~d'22-~
`~~26R ~I 46
`FIG.l.
`48~~W:~~~
`
`FIG.4.
`10.\
`--· d t7~-
`
`72
`
`FIG.6.
`
`FIG.5.
`
`

`

`U.S. Patent
`
`Oct. 6, 2009
`
`Sheet 2 of3
`
`US RE40,927 E
`
`UTILIZATION
`MEANS
`
`106ft
`
`104R
`
`106
`
`OZA
`
`OTI L IZATION
`MEANS
`
`~~~~
`~,29R
`
`l28R
`
`FIG. 8.
`
`FIG. 7.
`
`~84A
`
`94A
`
`FIG. 7a.
`
`FIG.7b.
`
`144
`
`FIG.9.
`
`

`

`U.S. Patent
`
`Oct. 6, 2009
`
`Sheet 3 of3
`
`US RE40,927 E
`
`FIG. 11.
`
`.
`FIG 10
`
`I
`
`192\
`
`190,
`COMMON
`POWER AND r- UTILIZATION
`CONlROL
`SYSTEM
`MEANS
`
`SCANNING AND v·
`r- ~2~- -:--J
`I
`ff-1 DETECTOR
`I HIGH ENERGY
`LASER GUN
`I
`
`OPTICAL
`SEARCH
`
`1
`I
`.I
`
`I
`I 184
`t"J-186
`- _j--180
`
`POSITIONING
`MEANS
`
`188
`
`19~
`
`19SR,
`
`19'5"
`
`'-194R
`
`..--
`
`~
`
`._
`96
`I
`z i/
`"' :1
`ar:: ._
`en
`z -
`
`:l
`
`,__
`
`I
`
`-
`FIG. 12.
`
`-
`
`-
`
`-
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`~12 ~0 ~12
`~10
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`21214
`
`Fl G. 14.
`
`6J~oo
`
`202
`
`6
`
`FIG. 13.
`
`

`

`US RE40,927 E
`
`1
`OPTICAL DETECTION SYSTEM
`
`Matter enclosed in heavy brackets [ ) appears in the
`original patent but forms no part ofthis reissue specifica(cid:173)
`tion; matter printed in italics indicates the additions
`made by reissue.
`Applicants herein have made the discovery that any type
`offocusing device in combination with a surface, exhibiting
`any degree of reflectivity and positioned near the focal plane
`of the device, acts as a retro-reflector. A retroreflector is 10
`defined as a reflector wherein incident rays or radiant energy
`and reflected rays are parallel for any angle of incidence
`within the field-of-view. A characteristic of a retroreflector is
`that the energy impinging thereon is reflected in a very nar(cid:173)
`row beam, herein referred to as the retroreflected beam. 1bis 15
`phenomenon is termed retroreflection.
`It is herein to be noted that the term radiant energy
`includes light energy, radio frequency, microwave energy,
`acoustical energy, X-ray energy, heat energy and any other
`types of energy which are part of the energy spectrum and 20
`which are capable of being retroreflected by the device,
`instrument or system sought to be detected.
`One type of optical device which exhibits this
`phenomenon, and thus is a particular type of retroreflector, is
`a corner reflector consisting of three mutnally perpendicular 25
`reflecting planes, However, this type of retroreflector is both
`difficult and expensive to fabricate.
`Due to the applicants discovery, it has now become pos(cid:173)
`sible to accomplish a great many feats heretofore considered
`impossible, as will become more apparent from the discus- 30
`sion to follow hereinafter. In this context it should be noted
`that the eyes of human beings, as well as those of animals,
`operate as retroreflectors. Also, any optical instrument which
`includes a focusing lens and a surface having some degree of
`reflectivity, no matter how small, positioned near the focal 35
`point of the lens, act as a retroreflector, whereby any radiant
`energy from a radiant energy source directed at these instru(cid:173)
`ments is reflected back towards the source in a substantially
`collimated narrow beam.
`It is therefore the primary object of the present invention 40
`to provide a. method and apparatus for detecting objects
`exhibiting retroreflection characteristics.
`It is another object of the present invention to provide a
`method and apparatus to detect objects having retroreflec(cid:173)
`tion characteristics by illuminating the same with a radiant 45
`energy source.
`It is a more particular object of the present invention to
`provide a method and apparatus for scanning an area to
`detect the presence of optical instruments such as
`binoculars, telescopes, periscopes, range finders, cameras,
`and the like.
`It is a further object of the present invention to provide
`means and apparatus for determining the characteristics of a
`device exhibiting retroreflection characteristics from a
`remote location.
`It is a further object of the present invention to provide a
`method and apparatus for detecting optical instruments for
`rendering the instruments ineffective and for neutralizing
`humans utilizing said instruments by employing lasers or
`similar high energy sources.
`It is yet another object of the present invention to provide
`a method and apparatus for transmitting and receiving radi(cid:173)
`ant energy utilizing concentric optics.
`These and other objects, features and advantages of the
`present invention will become more apparent from the fol(cid:173)
`lowing detailed discussion considered in conjnnction with
`the accompanying drawings, wherein:
`
`2
`FIG. 1 is a diagram showing a retroreflection system con(cid:173)
`sisting of a lens and a reflector wherein the source radiation
`is parallel to the optical axis of the lens.
`FIG. 2 is a diagram of a retroreflection system similar to
`that of FIG. 1, wherein the source radiation is not parallel to
`the optical axis of the lens.
`FIG. 3 is a diagram of a retroreflection system similar to
`FIG. 1 wherein the lens is imperfect so as to form an image
`rather than focusing at a single point.
`FIG. 4 is a diagram of a retroreflection system wherein
`the reflector is obliquely positioned with respect to the opti(cid:173)
`cal axis of the lens.
`FIG. 5 is a diagram of a human eye, wherein there is
`depicted the retroreflection characteristics thereof.
`FIG. 6 is a schematic representation depicting a beam
`splitting optical system for transmitting and receiving radi(cid:173)
`ant energy.
`FIG. 7 is a schematic representation depicting a concen(cid:173)
`tric optical system for transmitting and receiving radiant
`energy.
`FIG. 7a is a schematic representation of another embodi(cid:173)
`ment of the concentric optical system depicted in FIG. 7.
`FIG. 7b is a schematic representation of still another
`embodiment of the concentric optical system depicted in
`FIG. 7.
`FIG. 8 is a schematic representation depicting an ordi(cid:173)
`nary telescope as an image forming system having retrore(cid:173)
`flection characteristics.
`FIG. 9 is a schematic representation depicting one half of
`an ordinary binocular as an image forming system having
`retroreflection.
`FIG. 10 is a schematic representation depicting an ordi(cid:173)
`nary periscope as an image system having retroreflection
`characteristics.
`FIG. 11 is a schematic representation depicting an ordi(cid:173)
`nary camera as an image forming system having retroreflec(cid:173)
`tion characteristics.
`FIG. 12 depicts a system for scanning an area to detect
`the presence of optical instruments by utilizing the retrore(cid:173)
`flection characteristics thereof and for neutralizing observers
`using said optical instruments, and/or rendering the instru-
`ments ineffective.
`FIG.13 is a diagram of a radar system, and more particu(cid:173)
`larly of a radar antenna which is to be detected in accordance
`with the principles of the present invention.
`FIG. 14 depicts the waveforms obtained during the detec(cid:173)
`tion of the radar system shown in FIG. 13.
`In accordance with the general principles of the present
`invention an optical system consisting of a focusing lens and
`50 a reflective surface positioned near the focal plane of said
`lens has radiant energy rays supplied thereto by a radiant
`energy transmitter. The radiant energy rays reflected by the
`optical system due to its retroreflection characteristics are
`recovered by a radiant energy receiver to thereby detect the
`55 presence and relative position of said optical system. The
`output of the radiant energy receiver may be applied to a
`utilization means for determining the characteristics of the
`retroreflector or for directing a weapon means.
`Referring now to the drawings and more particularly to
`60 FIG. 1 thereof, there is shown an optical system consisting
`of a lens 20 and a reflective surface 22, which herein is a
`mirror, positioned in the focal plane 24 of the lens 20. Rays
`of radiation 26 and 28, respectively, are directed towards the
`system, and more particularly towards the lens 20, from a
`65 radiation source (not shown); the incident rays in the present
`illustration being parallel to the optical axis 30 of the lens. It
`is herein to be noted that for the purpose of clarity the inci-
`
`

`

`US RE40,927 E
`
`10
`
`3
`dent rays are herein shown as being confined to the top half
`of the lens 20. The incident rays 26 and 28 are refracted by
`the lens 20 and focused at the focal point 32 of the lens,
`which focal point lies on the mirror 22. The rays are then
`reflected by the mirror so that the angle of reflection equals
`the angle of incidence, and are returned to the lower half of
`the lens where they are again refracted and emerge there(cid:173)
`from as retroreflected rays 26R and 28R. The rays 26R and
`28R are returned to the radiation source parallel to the inci(cid:173)
`dent rays 26 and 28 thereof. However, as shown in the
`drawing, the relative positions of the rays 26 and · 28 are
`inverted so that the image returned to the radiation source is
`also inverted.
`In the optical system depicted in FIG. 2, similar parts are
`de-noted by similar reference numerals. In this system the
`rays 34 and 36 are not parallel to the optical axis 30A of both 15
`the lens 20A and the mirror 22A, the mirror 22A being posi(cid:173)
`tioned in the focal plane 24A of the lens. The rays 34 and 36
`are refracted by the lens 20A and focused at a point 37
`removed from the optical axis but still on the focal plane.
`The rays 34 and 36 are reflected by the mirror. Both of the 20
`rays 34 and 36 would normally emerge from the lens as
`retroreflected rays 34R and 36R, after refraction by the lens,
`and would be returned to the source of the rays 34 and 36 in
`a direction parallel thereto. However, since the lens 20A is of
`finite size, the reflected ray 34R will miss the lens and will 25
`not be retroreflected .. The loss of reflected rays in this man(cid:173)
`ner is called "vignetting".
`In the system depicted in FIG. 3 wherein similar parts are
`de-noted by similar reference numerals, the lens 20B is
`assumed to be imperfect; i.e., it has aberrations. In this case 30
`the rays 38 and 40 are parallel to the optical axis 30B but are
`not focused at a single point on the focal plane 24B, and
`instead form an image on the mirror 22B, which image is
`referred to as the circle of confusion. In most practical opti-
`cal systems there are circles of confusion and the mirror is 35
`normally positioned at the plane of least circle of confusion,
`herein depicted by the· reference numeral 42. Thus, the
`image formed on the mirror by means of the rays 38 and 40
`can be considered to be a radiant source, and the retrore(cid:173)
`flected rays 38R and 40R exit from the lens 20B substan- 40
`tially parallel to each other. This is possible since each
`emerging ray can be paired with a parallel incident ray
`which radiates from a· common point of the image source
`located at the mirror 22B. ·
`In the system depicted in FIG. 4, the reflecting surface or 45
`mirror 22C, and its axis 44, is tilted with respect to the opti-
`cal axis 30C of lens 20C. However, the ray 48 is again ret(cid:173)
`roreflected by the system and the retroreflected ray 48R is
`returned parallel to the incident ray 48. The retroreflected
`ray 46R, due to the ray 46, is lost because of vignetting.
`The concept set forth herein above in conjunction with
`FIG. 3, that the retroreflected rays be considered as radiating
`from a source on the image plane, is highly significant. With
`this concept in mind, it will be readily apparent that even if
`the retroreflecting surface is dispersive, curved, or tilted, (as 55
`shown in FIG. 4), the system will still exhibit retroreflective
`properties for any and all rays which are returned to the lens
`by the reflecting surface.
`The rays retroreflected by the optical systems depicted in
`FIGS. 1 to 4 are in the form of a narrow, substantially colli- 60
`mated beam having a high radiant flux density. It is to be
`noted that there is an actual increase in the radiant flux den(cid:173)
`sity ofthe retroreflected beam due to the narrowing thereof.
`This increase in radiant flux density is herein termed optical
`gain.
`For example, if the irradiance produced by the radiating
`source at the collecting lens in FIG. 3 is 100 watts/cm2 and
`
`4
`the area of the lens is IOO cm2
`, then the radiant flux at the
`image or focal plane (circle of confusion) is
`
`100 Watts
`
`--cruz-- x 100 cm2
`
`. or 104 watts.
`
`It is a characteristic of a retroreflector to return the ret(cid:173)
`roreflected energy or rays in a very narrow beam. The
`dimensions of the retroreflected beam is a function of the
`angular resolution of the retroreflector which includes the
`lens and the reflecting surface.
`The solid angle into which the incident radiant flux will
`be retroreflected is determined by the square of the angular
`resolution of the retroreflector. If, for example, the resoltuion
`of the optical system is I 0-4 radians, the solid angle into
`which the retroreflected beam will be returned is 10-8 stera(cid:173)
`dians. One steradian being the solid angle subtended at the
`center of a sphere by a portion of the surface of area equal to
`the square of the radius of the sphere. Thus at a distance of
`I if em from the focal plane the area of the retroreflected
`beam is only 1.0 cm2
`• The retroreflector, by radiating into
`such a small solid angle, has radiant intensity of
`
`104 watts
`, or 1012 watts/steradian.
`-4
`I 0
`steradian
`
`In order to obtain a measure of the optical gain we must
`compare the retroreflector to a standard or reference. This
`reference has been taken to be a diffuse surface known in the
`art as a Lambertian radiator. If the 104 watts of incident
`radiant flux were simply re-radiated in a Lambertian man(cid:173)
`ner; i.e., into a solid angle of3.I4 (1t) steradians, the radiant
`intensity would be
`
`104 watts
`3
`3.14 steradians' or 3.1 x 10
`
`watts/steradian.
`
`Thus, the retroreflector has an overall optical gain equal to
`
`1012 watts/steradian
`8
`- - - : - - - - - , or 3.14x!O
`3.1 X 103 watts/steradian
`
`Although there is no actual increase in radiant flux, the
`retroreflector has a radiant intensity which is 3.I4xi08
`greater than that of a Lambertain radiator which emits the
`same radiant flux. Thus, for example, a telescope having a
`collecting area of 100 cm2 and an angular resolution of 0.1
`50 milliradian would appear similar in size to about 3.5xi08
`cm2 of a diffuse or Lambertain radiator.
`It should be noted that in almost all cases, the retroreflec-
`tor will be disposed within an environment that produces
`background radiation in a Lambertain manner. Thus, the
`radiant intensity of the retroreflector is so much greater than
`that of a Lambertain radiator that it is easily discernible from
`the background, even when, (as shown in FIG. 2) a large
`percentage of the retroreflected radiant flux is lost due to
`vignetting.
`It is herein to be noted that the radiant intensity of the
`retroreflected beam is dependent upon the characteristics of
`the optical system employed. If an optical system of the type
`shown in FIGS. 1, 2, and 4 were possible and there were no
`loss of energy (power) entering the system, then the radiant
`65 intensity gain would be almost infinite since the energy
`would be retroreflected in an almost perfectly collimated
`beam, i.e. a retroreflected beam whose divergence angle is
`
`

`

`US RE40,927 E
`
`10
`
`5
`almost zero. However, almost all optical systems resemble
`that shown in FIG. 3 and the factor which determined the
`divergence angle of the retroreflected beam is the size of the
`circle of confusion and more particularly, the least circle of
`confusion. The size of the least circle of confusion is depen(cid:173)
`dent upon the resolution of the system and in particular upon
`the resolution of focusing lens. Thus, the less aberrations in
`the lens, the better the resolution, the smaller the circle of
`least confusion, the smaller the divergence angle of the ret(cid:173)
`roreflected beam, and thus the greater the optical gain.
`Referring to FIG. 5, there is shown a magnified cross(cid:173)
`sectional view of a human eye denoted generally by the ref(cid:173)
`erence numeral 50. The eye includes a cornea 52, an anterior
`chamber 54, a lens 56, and a retina 58. The retina has a small
`portion or point 60 thereon termed the yellow spot or macula
`lutea, which is approximately 2 mm in diameter. At the cen(cid:173)
`ter of the macula lutea is the fovea centralis 62 whose diam(cid:173)
`eter is approximately 0.25 m. The acuity of vision is greatest
`at the macula lutea and more particularly at the fovea centra(cid:173)
`lis. Thus, the eye is always rotated so that the image being
`examined or the rays entering thereon fall on the fovea 62.
`As seen in FIG. 5, rays 64 and 66 enter the eye and pass
`through the cornea 52 and the anterior chamber 54 and are
`refracted by the lens 56 and focused on the fovea centralis
`portion 62 of the retina 58. The rays are then. reflected, pass(cid:173)
`ing through the lens 56, anterior chamber 54 and cornea 52
`and emerge therefrom as retroreflected rays 64R and 66R
`which are parallel to the rays 64 and 66. Thus, it is seen that
`even the human eye acts as a retroreflector.
`Referring now to FIG. 6, there is shown an optical system
`for transmitting and receiving radiant energy, the more par(cid:173)
`ticularly a beam splitter for transmitting radiant energy and
`for receiving or recovering a portion of said radiant energy.
`The beam splitter includes an optical bench 70 having an
`optical system consisting of a lens 72 and a rotating pattern 35
`or reticle 74, which may also be a modulator, said system
`being placed on said bench. The beam splitter also includes a
`radiant energy source 76, a collimator 78, a thin plate of
`glass 80 having a semi-reflective coating thereon, a detector
`82. In the operation of the beam splitter, the radiant energy 40
`from the source 76 is collimated to form a beam by the
`collimator 78 and the beam is directed upon the glass plate
`80, a portion of the energy in the beam being reflected and a
`portion of the energy in the beam being transmitted by the
`glass plate. The energy is then transmitted down the optical 45
`bench 70 where the lens refracts the transmitted energy and
`focuses the beam upon the reticle 74 from whence is is ret(cid:173)
`roreflected back to the glass plate. A portion of the retrore(cid:173)
`flected energy passes through the glass plate and is lost, and
`a portion thereof is reflected by the glass plate and detected so
`by means of the detector and the output thereof is then fed to
`the utilization means 83. The detector 82 is thus effectively
`positioned within or concentric with the retroreflected
`energy beam without affecting the transmission of radiant
`energy from the source to the optical system. The energy 55
`obtained by the utilization means can be used to obtain the
`spectral and temporal characteristics of the retroreflected
`beam, and may the be compared with the transmitted beam
`to determine various characteristics of the optical system
`being investigated. It will be apparent that the use of this test 60
`instrument makes possible the investigation and character(cid:173)
`ization of optical systems in terms of recording the retrore(cid:173)
`flective characteristics thereof.
`The rotating pattern or reticle 74 can be replaced with a
`reflective surface and a modulator placed on the light inci- 65
`dent side of the lens 72. The modulator can then be tilted so
`that none of the light reflected from its surface returns to the
`
`6
`beam splitter 80 to be reflected to the detector 82. The only
`light then returning to the detector 82 will be that modulated
`by the modulator and reflected back from the reflective sur(cid:173)
`face replacing the reticle 74.
`FIG. 7 depicts a folded concentric optical system for
`transmitting and receiving radiant energy-also known as an
`optical transceiver. The optical transceiver 84 includes a pri(cid:173)
`mary mirror 86 having a substantially parabolic shape, a
`secondary mirror 88 having a planar configuration, a radiant
`energy source 90, a detector 92 and a utilization means 94.
`The primary mirror has an aperture 96 concentric with its
`principal axis and the principal axis of the secondary mirror
`is aligned so as to be coaxial therewith. The light source and
`detector are also aligned with the mirrors so that all of the
`aforesaid elements are concentrically disposed with respect
`15 to each other. The light source is positioned adjacent to the
`nonreflecting surface of the primary mirror while the detec(cid:173)
`tor is positioned adjacent to the nonreflecting surface of the
`secondary mirror.
`In the operation of the transceiver 84, rays 98 and 100 are
`20 emitted by the radiant energy source 90, and impinge upon
`the secondary mirror 88, from whence they are reflected and
`impinge upon the primary mirror 86. The rays are then
`reflected by the primary mirror and directed towards an opti(cid:173)
`cal instrument 102 which exhibits retroreflective characteris-
`25 tics. The incident rays are retroreflected by the optical instru(cid:173)
`ment 102 and are returned as retroreflected rays 98R and
`100R. The rays 98R and 100R return in a direction parallel
`to the rays 98 and 100 and impinge upon the primary mirror
`86 and are reflected thereby towards the detector 92 where
`30 they are detected, and the detector output signal is then fed to
`the utilization means 94.
`As discussed previously, the term optical instruments
`exhibiting retroreflective characteristics include the eyes of
`animals and humans.
`A second embodiment of a folded concentric optical
`transceiver is shown in FIG. 7a, wherein similar parts are
`denoted by similar reference numerals.
`In this embodiment the light source 90A is positioned
`adjacent to the nonreflecting surface of the secondary mirror
`88A and the detector 92A is positioned adjacent to the non(cid:173)
`reflecting surface of the primary mirror 86A.
`In the operation of the transceiver 84A, rays 104 and 106
`are emitted by the radiant energy source 90A, and impinge
`upon the primary mirror 86A, from whence they are
`reflected towards the optical instrument 102A. The rays are
`retroreflected by the optical instmment and are returned as
`retroreflected rays 1 04R and 1 06R. The rays 1 04R and 1 06R
`return in a direction parallel to the rays 104 and 106 and
`impinge upon the primary mirror and are reflected thereby
`towards the secondary mirror through the aperture 96A to
`the detector 92A, and the output signal of the detector is then
`fed to the utilization means 94A.
`A third embodiment of a folded concentric optical trans(cid:173)
`ceiver is depicted in FIG. 7b, wherein similar parts are
`denoted by similar reference numerals.
`In this embodiment, the detector 92B is once more posi(cid:173)
`tioned adjacent to the nonreflecting surface of the secondary
`mirror 8SB and the radiant energy source 90B is positioned
`between the reflecting surfaces of the primary mirror 868
`and the secondary mirror 88B. There is also included a col(cid:173)
`lector 108, which may be an elliptically shaped mirror for
`collecting the spurious radiation rays from the source 908
`and reflecting back upon the source, wherefrom they are
`directed upon the secondary mirror and ultimate! directed
`toward the optical instrument 1028.
`In the operation of the transceiver 84B, energy from the
`radiant energy source 90B impinges upon the secondary mir-
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`US RE40,927 E
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`7
`ror 888, and more particularly rays 110 and 112 so impinge.
`These rays are reflected by the secondary mirror towards the
`primary mirror, from where they are once more reflected
`towards the optical instrument 1028. The incident rays 110
`and 112 are then retroreflected by the optical instrument and
`returned as retroreflected rays llOR and 112R. The rays
`11 OR and 112R return in a direction parallel to the rays 110
`and 112 and impinge upon the primary mirror and are
`reflected thereby towards the detector 928 where they are
`detected and the output thereof is then fed to the utilization 10
`means94B.
`It is herein to be noted that although the folded optical
`transceivers depicted in FIGS. 7, 7a, and 7b have been
`shown as being concentric, it is also possible to employ the
`above type of transceivers wherein their optical characteris- 15
`tics are not concentric. However, it has been found from the
`view-point of efficiency and efficacy that the concentric opti-
`cal transceivers are more desireable.
`FIG. 8 is an optical schematic representation of a tele(cid:173)
`scope having an objective lens 116, a reticle 118, a pair of 20
`erector lenses 120 and 122, a field lens 124, and an eyelens
`126.
`Thus, when rays 128 and 129 are directed towards the
`objective 20 lens 116, they are focused on the reticle 118 and
`retroreflected thereby to produce retroreflected rays 128R 25
`and 129R respectively, whose direction is opposite and par(cid:173)
`allel to that of the incident rays 128 and 129. Thus, the
`combination of the objective lens 116, and the reticle 118
`form a retroreflective optical instrument, in and of them(cid:173)
`selves.
`It is herein to be noted that even if the reticle 118 is merely
`plain glass, as in most cases it is, it still exhibits some degree
`of reflectivity, which reflectivity gives rise to the retrore(cid:173)
`flected rays 128R and 129R.
`It is herein also. to be noted that incident rays passing 35
`through the telescope to the eye of the observer are also
`retroreflected by the eye of the observer. Thus, there is in
`effect, two retroreflective optical systems and thus two ret(cid:173)
`roreflective signals.
`FIG. 9 is an optical schematic representation of one half 40
`of a binocular and comprises an objective lens 132, a first
`porro prism 134, a second porro prism 136, a reticle 138, a
`field lens 140, and an eyelens 142. When a ray such as 144 is
`incident on the objective lens 132, it is focused thereby on
`the reticle 138, after passing through the porro prisms 134 45
`and 136. It is herein to be noted that although the ray 144 is
`directed along a path which is not straight; i.e., there are
`several right angle bends therein, the entire path is still part
`of the focal path of the instrument. Thus, the ray 144 is
`focused on the reticle 138, causing the same to be retrore- 50
`fleeted as ray 144R which then goes through a path similar to
`that of ray 144 and emerges from the objective lens 132 in a
`direction which is opposite and parallel to that of the inci(cid:173)
`dent ray 144. It is to be noted that the description herein
`above describing a single ray is for purposes of simplicity of 55
`explanation.
`FIG. 10 is an optical schematic representation of a peri(cid:173)
`scope. The periscope includes a window 146, an objective
`prism 148, an objective lens 149, an amici prism 150, an
`erecting prism assembly 152, a reticle 154, a field lens 156, 60
`an eyelens 158, and a filter 160. An incident ray 162 enters
`the periscope through the window 146, then passes through
`the prism 148, objective lens 149, amici prism 150, and
`erecting prism assembly 152 to the reticle 154 whereon the
`incident ray is reflected and emerges from the periscope as 65
`retroreflected ray 162R whose direction is opposite and par(cid:173)
`allel to the incident ray 162. Again it is to be noted that the
`
`8
`description above describing a single ray is merely for the
`purpose of simplicity of explanation.
`FIG. 11 is an optical schematic representation of a cam(cid:173)
`era. The camera includes a lens 164, a shutter 166, and film
`168. In the operation of the camera when a picture is taken
`the shutter opens and incident rays 170 and 171 are focused
`on the film 168 through an aperture 172 in the shutter, by
`means of the lens 164. These rays are then reflected by the
`film and emerge from the lens as retroreflected rays 170R
`and171R.
`It is to be noted that most, if not all, optical systems will
`have a reflecting surface such as a reticle, a lens, or a prism
`in the focal plane, and the incident radiation will be retrore-
`flected by any such surface.
`Referring now to FIG. 12, there is shown one embodiment
`of a system for detecting the presence of an optical
`instrument, for tracking said instrument, and for neutralizing
`observers utilizing said instrument and/or rendering the
`instrument ineffective.
`The system includes a scanner 180, including an optical
`searching means 182, such as a source of infrared light, a
`detector 184, and a laser 186. It is herein to be noted that the
`search means 182 and the detector 184 may be combined in
`the form of a transceiver as described hereinbefore in con(cid:173)
`junction with FIGS. 7, 7a, and 7b. The scanner 182 is con(cid:173)
`trolled by a scanning and positioning means 188, which
`includes a servo motor (not shown). The scanning and posi(cid:173)
`tioning means 188 is powered