`
`
`
`EXHIBIT
`
`EXHIBIT
`1009
`
`1009
`
`

`

`US 6,603,134 B1
`(10) Patent No.:
`(12)Un1ted States Patent
`
`Wild et al.
`(45) Date of Patent:
`Aug. 5, 2003
`
`US006603134B1
`
`(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)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.2 04/623,186
`(22)
`Filed:
`Mar. 10, 1967
`
`(51)
`
`(52) US. Cl.
`
`Int. Cl.7 ........................... B64D 1/04; G01B 11/26;
`G01] 5/02
`........................ 250/526; 89/111; 250/342,
`356/1381
`(58) Field of Search ....................... 343/18 E; 331/945,
`250/8331 R, 526, 342; 88/1 M, 1 U; 356/209,
`138.1; 89/1.11
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`2/1962 Kingsbury ................. 88/1 Ux
`3,020,792 A *
`
`7/1963
`250/833
`3,098,932 A *
`3,215,842 A * 11/1965 Thomas .................... 343/18 X
`4,112,300 A *
`9/1978 Hall et al.
`OTHER PUBLICATIONS
`
`Electronics, Nov. 10, 1961, pp. 81—85.*
`
`* cited by examiner
`
`Primary Examiner—Stephen C. Buczinski
`(74) Attorney, Agent, or Firm—Daniel J. Long
`
`(57)
`
`ABSTRACT
`.
`.
`.
`.
`The present invention pertains to radlant 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-
`tioned near the focal plane of the device, and wherein
`incident radiation falling within the field-of-View of said
`system is reflected back in a direction which is parallel to the
`incident radiation. The present invention has great applica-
`bility in military optical system applications for detecting
`the presence of an enemy employing surveillance equipment
`and for neutralizing this surveillance capability.
`
`2,970,310 A *
`
`1/1961 Bruce ....................... 343/13 X
`
`47 Claims, 3 Drawing Sheets
`
`
`
`Panasonic Corporation
`
`Exhibit 1009
`
`

`

`US. Patent
`
`Aug. 5, 2003
`
`Sheet 1 0f3
`
`US 6,603,134 B1
`
`
`
`
`
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`US. Patent
`
`Aug. 5, 2003
`
`Sheet 2 0f3
`
`US 6,603,134 B1
`
`
`
`
`
`

`

`US. Patent
`
`Aug. 5, 2003
`
`Sheet 3 0f3
`
`US 6,603,134 B1
`
`I7|
`
`I70
`
`|66
`
`l68
`
`164
`
`
`FIG. 10.
`
`
`SCANNING AND
`POSITIONING
`MEANS
`
`
`
`I88
`
`I90
`
`COMMON
`
`POWE R AN D
`CONTROL
`MEANS
`
`SEA R C H
`
` OPTICAL
`
`
`INSTRUMENT
`
`HIGH ENERGY
`
`LASER GUN
`
`
`FIG. 12.
`
`f
`
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`FIG. 13.
`
`

`

`US 6,603,134 B1
`
`1
`OPTICAL DETECTION SYSTEM
`
`Applicants herein have made the discovery that any type
`of focusing 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
`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. Acharacteristic of a retroreflector is
`that the energy impinging thereon is reflected in a very
`narrow beam, herein referred to as the retroreflected beam.
`This 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
`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 mutually perpen-
`dicular reflecting planes, However, this type of retroreflector
`is both difficult and expensive to fabricate.
`Due to the applicants discovery,
`it has now become
`possible to accomplish a great many feats heretofore con-
`sidered impossible, as will become more apparent from the
`discussion 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 instru-
`ment which includes a focusing lens and a surface having
`some degree of reflectivity, no matter how small, positioned
`near the focal point of the lens, act as a retroreflector,
`whereby any radiant energy from a radiant energy source
`directed at these instruments is reflected back towards the
`source in a substantially collimated narrow beam.
`It is therefore the primary object of the present invention
`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-
`tion characteristics by illuminating the same with a radiant
`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
`radiant energy utilizing concentric optics.
`These and other objects, features and advantages of the
`present
`invention will become more apparent from the
`following detailed discussion considered in conjunction
`with the accompanying drawings, wherein:
`FIG. 1 is a diagram showing a retroreflection system
`consisting 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.
`
`2
`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
`optical 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-
`ant energy.
`FIG. 7 is a schematic representation depicting a concen-
`tric optical system for transmitting and receiving radiant
`energy.
`FIG. 7a is a schematic representation of another embodi-
`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-
`nary telescope as an image forming system having retrore-
`flection characteristics.
`
`10
`
`15
`
`20
`
`FIG. 9 is a schematic representation depicting one half of
`an ordinary binocular as an image forming system having
`retroreflection.
`
`25
`
`FIG. 10 is a schematic representation depicting an ordi-
`nary periscope as an image system having retroreflection
`characteristics.
`
`30
`
`FIG. 11 is a schematic representation depicting an ordi-
`nary camera as an image forming system having retrore-
`flection characteristics.
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`FIG. 12 depicts a system for scanning an area to detect
`the presence of optical instruments by utilizing the retrore-
`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
`particularly 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
`detection 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
`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
`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
`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
`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
`incident 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
`
`

`

`US 6,603,134 B1
`
`3
`the lens where they are again refracted and emerge there-
`from as retroreflected rays 26R and 28R. The rays 26R and
`28R are returned to the radiation source parallel to the
`incident 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
`the lens 20A and the mirror 22A, the mirror 22A being
`positioned 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
`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
`not be retroreflected. The loss of reflected rays in this
`manner 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
`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
`optical systems there are circles of confusion and the mirror
`is 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
`retroreflected rays 38R and 40R exit from the lens 20B
`substantially 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
`mirror 22C, and its axis 44, is tilted with respect to the
`optical axis 30C of lens 20C. However, the ray 48 is again
`retroreflected 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
`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
`collimated beam having a high radiant flux density. It is to
`be noted that there is an actual increase in the radiant flux
`
`density of the 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
`the area of the lens is 100 cm2, then the radiant flux at the
`image or focal plane (circle of confusion) is
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`4
`
`
`100 watts
`cm2
`
`X100 cmz,
`
`or 104 watts.
`
`It
`
`is a characteristic of a retroreflector to return the
`
`retroreflected 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 10'4 radians, the solid angle into
`which the retroreflected beam will be returned is 10'8
`steradians. 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 104 cm 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
`
`,
`12
`104 watts
`l 0’
`steradian
`f , or 10 watts/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-
`ner; i. e., into a solid angle of 3.14 (at) steradians, the radiant
`intensity would be
`
`104 watts
`3.14 steradians’ or 3.1 X 10 watts/steradian
`
`Thus, the retroreflector has an overall optical gain equal to
`
`1012 watts/steradian
`3.1 X 103 watts/steradian
`
`,
`
`or 3.l4>< 10
`
`8
`
`Although there is no actual increase in radiant flux, the
`retroreflector has a radiant
`intensity which is 3.14><108
`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
`milliradian would appear similar in size to about 3.5><108
`cm2 of a diffuse or Lambertian radiator.
`It should be noted that in almost all cases, the retrore-
`flector will be disposed within an environment that produces
`background radiation in a Lambertian manner. Thus, the
`radiant intensity of the retroreflector is so much greater than
`that of a Lambertian 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
`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 6,603,134 B1
`
`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
`dependent upon the resolution of the system and in particu-
`lar upon the resolution of the 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 retroreflected beam, and thus the greater the
`optical gain.
`Referring to FIG. 5, there is shown a magnified cross-
`sectional view of a human eye denoted generally by the
`reference 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 center of the macula lutea is the fovea
`centralis 62 whose diameter is approximately 0.25 m. The
`acuity of vision is greatest at the macula lutea and more
`particularly at the fovea centralis. 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, passing 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
`particularly 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
`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
`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
`bench 70 where the lens refracts the transmitted energy and
`focuses the beam upon the reticle 74 from whence is is
`retroreflected back to the glass plate. A portion of the
`retroreflected energy passes through the glass plate and is
`lost, and a portion thereof is reflected by the glass plate and
`detected 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 retrore-
`flected energy beam without affecting the transmission of
`radiant energy from the source to the optical system. The
`energy obtained by the utilization means can be used to
`obtain the spectral and temporal characteristics of the ret-
`roreflected beam, and may the be compared with the trans-
`mitted beam to determine various characteristics of the
`
`optical system being investigated. It will be apparent that the
`use of this test instrument makes possible the investigation
`and characterization of optical systems in terms of recording
`the retroreflective characteristics thereof.
`
`The rotating pattern or reticle 74 can be replaced with a
`reflective surface and a modulator placed on the light
`
`6
`incident side of the lens 72. The modulator can then be tilted
`so that none of the light reflected from its surface returns to
`the 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 surface 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
`primary 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 aperature 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
`to each other. The light source is positioned adjacent to the
`nonreflecting surface of the primary mirror while the detec-
`tor is positioned adjacent to the nonreflecting surface of the
`secondary mirror.
`In the operation of the transceiver 84, rays 98 and 100 are
`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
`optical instrument 102 which exhibits retroreflective char-
`acteristics. The incident rays are retroreflected by the optical
`instrument 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 they are detected, and the detector output signal is
`then fed to the utilization means 94.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`instruments
`the term optical
`As discussed previously,
`exhibiting retroreflective characteristics include the eyes of
`animals and humans.
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`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
`nonreflecting 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 instrument and are returned as
`retroreflected rays 104R and 106R. The rays 104R and 106R
`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-
`ceiver is depicted in FIG. 7b, wherein similar parts are
`denoted by similar reference numerals.
`In this embodiment,
`the detector 92B is once more
`positioned adjacent to the nonreflecting surface of the sec-
`ondary mirror 88B and the radiant energy source 90B is
`positioned between the reflecting surfaces of the primary
`mirror 86B and the secondary mirror 88B. There is also
`included a collector 108, which may be an elliptically
`shaped mirror for collecting the spurious radiation rays from
`the source 90B and reflecting back upon the source, where-
`from they are directed upon the secondary mirror and
`ultimatel directed toward the optical instrument 102B.
`
`

`

`US 6,603,134 B1
`
`7
`In the operation of the transceiver 84B, energy from the
`radiant energy source 90B impinges upon the secondary
`mirror 88B, 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 102B. The incident
`rays 110 and 112 are then retroreflected by the optical
`instrument and returned as retroreflected rays 110R and
`112R. The rays 110R 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 92B where
`they are detected and the output thereof is then fed to the
`utilization means 94B.
`
`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 character-
`istics are not concentric. However, it has been found from
`the view-point of efficiency and efficacy that the concentric
`optical transceivers are more desireable.
`FIG. 8 is an optical schematic representation of a tele-
`scope having an objective lens 116, a reticle 118, a pair of
`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
`and 129R respectively, whose direction is opposite and
`parallel 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-
`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-
`flected rays 128R and 129R.
`It is herein also to be noted that incident rays passing
`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
`retroreflective signals.
`FIG. 9 is an optical schematic representation of one half
`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
`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-
`flected 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
`incident ray 144. It is to be noted that the description herein
`above describing a single ray is for purposes of simplicity of
`explanation.
`FIG. 10 is an optical schematic representation of a peri-
`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,
`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
`
`10
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`15
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`20
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`25
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`30
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`35
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`45
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`8
`retroreflected ray 162R whose direction is opposite and
`parallel to the incident ray 162. Again it is to be noted that
`the 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-
`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
`and 171R.
`
`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
`
`conjunction with FIGS. 7, 7a, and 7b. The scanner 182 is
`controlled by a scanning and positioning means 188, which
`includes a servo motor (not shown.) The scanning and
`positioning means 188 is powered by a power and control
`means 190, which means also supplies power for the scanner
`180, and a utilization system 192.
`In the operation of the system, the scanner 180 is caused
`to scan a preselected area by means of the scanning and
`positioning means 188, the means 188 being programmed
`by the utilization system 192. The optical searching means
`emits rays 194 and 195, when these rays impinge upon an
`optical
`instrument 196 exhibiting retroreflective
`characteristics, as hereinbefore described, they are retrore-
`flected as retroreflected rays 194R and 195R respectively,
`and detected by the detector 184 and the detector output is
`then fed to the utilization system 192. The utilization system
`may be programmed to merely track the instrument 196, in
`which case, this information would be fed to the scanning
`and positioning means 188 and thence to the scanner 180
`causing it to track said instrument. However, if it is desired
`to neutralize the observer using the instrument, or to render
`the instrument ineffective, then the utilization system 192
`will feed a signal to the laser 186 activating the same and
`causing a high intensity laser beam to be directed at the
`instrument,
`thereby accomplishing the aforementioned
`objects.
`It is herein to be noted that although the present system
`has been described as employing a laser, it is also possible
`to use any other high energy system, weapon, or weapon
`system.
`it will be readily apparent to
`With the present system,
`those skilled in the art, that a hostile satellite orbiting the
`earth and employing optical surveillance equipment
`to
`monitor a country’s activities can be detected and its sur-
`veillance capability destroyed.
`It is herein again to be noted that the aberrations in almost
`all optical
`instruments cause a small divergence of the
`retroreflected rays,
`the amount of said divergence being
`governed by the resolution of the retroreflector. As a prac-
`tical matter the angular resolution of optical systems such as
`binoculars, periscopes, telescopes, cameras, and optical sys-
`
`

`

`US 6,603,134 B1
`
`9
`
`tems carried by missiles will be between about 10'3 and
`10'5 radians which produce retroreflected beams of 10'6 to
`10'10 steradians. At a range of 1,000 feet the area of these
`beams would be 1.0 and 10'4 ft2 respectively. This diver-
`gence is so small so that the retroreflected rays are substan-
`tially collimated.
`It is herein to be noted that in microwave application
`corner reflectors have been utilized for retroreflecting pur-
`poses. However, the present invention enables the detection
`of microwave apparatus, such as antennas and the like which
`do not have a corner reflector as an integral part thereof, by
`utilizing the inherent retroreflection characteristics of the
`apparatus as hereinbefore discussed. Thus, this apparatus
`and systems eXhibiting the retroreflection phenomenon can
`be similarly detected by the use of radio frequency,
`microwave, X-ray, acoustical or any similar types of energy
`directed thereat.
`