Tracking mirror

Information

  • Patent Grant
  • 6705740
  • Patent Number
    6,705,740
  • Date Filed
    Monday, July 24, 2000
    24 years ago
  • Date Issued
    Tuesday, March 16, 2004
    20 years ago
Abstract
An apparatus that appears to actively track the position of a viewer by producing a red circle about the viewer's image, seen in a security mirror. The red circle appears to translate and rotate to track the viewer's position. Rotational tracking operates independently of the mirror.
Description




This Invention is based on my previous work expressed in U.S. Pat. No. 4,971,312, ILLUSION APPARATUS, U.S. Pat. No. 5,681,223, TRAINING VIDEO METHOD AND DISPLAY, and, particularly, U.S. Pat. No. 5,871,404, OPTICAL BLOB, the contents of each being here incorporated by reference thereto.




BACKGROUND




The Tracking Mirror is preferably used in place of typical security mirrors commonly used in retail stores to catch shoplifters. Security mirrors are convex, to allow wide angle coverage, and are generally mounted near or on the store's ceiling, to provide unobstructed aerial views. Commonly, store personnel monitor the premises by occasional glances at the mirrors. Security mirrors are often semi-transparent (i.e., with reflective coating thin enough to allow some light to pass through) to allow video cameras or security personnel to carry out hidden surveillance from behind the mirrors.




In most cases it is unlikely that security personnel are peering down through a mirror. It is also unlikely that a video camera will at any moment be properly positioned to catch a shoplifter in the act and, even if a camera sees the act, security personnel may not be monitoring that camera at that time. A potential shoplifter will, however, check reflections in the security mirrors to see if personnel in the store are watching him/her.




GENERAL DESCRIPTION




It is a purpose of this Invention to deter theft (and/or other crimes) by adding an additional factor of intimidation to dissuade potential shoplifters from becoming “kinetic” shoplifters. Under the preferred embodiment, when a potential shoplifter looks up to check a security mirror (to see if store personnel are watching), he/she sees a red circle about his/her own reflection in the mirror.




The Invention appears in a preferred embodiment for each of the two commonly known security mirror types.











DESCRIPTIONS OF THE FIGURES





FIG. 1

is a side section through the centerline of the mirror and conical housing of the first preferred embodiment.





FIG. 2A

is a side section through a lamp housing attached to the conical housing of

FIG. 1







FIG. 2B

is a front elevation showing the preferred red circle in a transparency.





FIG. 3

is a side section through a light catcher attached to the conical housing of FIG.


1


.





FIG. 4

is a side section through a wide-angle light catcher attached to the conical housing of FIG.


1


.





FIG. 5

is a side section through a perforated convex mirror.





FIG. 6

is a side section through the centerline of the hemispherical mirror (with a lamp housing) of the second preferred embodiment.





FIG. 7A

is a section through the centerline of the transparent globe of the second preferred embodiment. The right side of the figure shows a typical meridian; the left side shows a typical parallel.





FIG. 7B

shows the meridians of

FIG. 7A

projected to an elevation.





FIG. 7C

is a detail section through a masked groove in the transparent globe of the second preferred embodiment.





FIG. 7D

shows the parallels of

FIG. 7A

projected to an inverted plan view.





FIG. 8A

is a plan section through the equator of an alternative globe for the second preferred embodiment.





FIG. 8B

is an elevation of the visible pattern of the alternative globe of FIG.


8


A.





FIG. 9A

is a side section through the spinning ring of an alternative to the second preferred embodiment.





FIG. 9B

is a plan section through one side of the ring of FIG.


9


A.





FIG. 9C

is an alternative to the embodiment shown in FIG.


9


B.





FIG. 10

is an isometric drawing of an alternative to the illuminated object of the second preferred embodiment.





FIG. 11A

is a front elevation of the turning disk used in an enhancement to the first preferred embodiment.





FIG. 11B

is a front elevation of the spinning disk used in an enhancement to the first preferred embodiment or an alternative in the second preferred embodiment.





FIG. 11C

is a side section of one embodiment of the disk of FIG.


11


B.





FIG. 12

shows a moiré version of the circle of the first preferred embodiment.





FIG. 13

is a side section through the centerline of an alternative transparent globe of the second preferred embodiment. The left side of the figure shows a surface pattern; the right side shows an etched pattern.











FIRST PREFERRED EMBODIMENT




The first preferred embodiment


100


incorporates a shallow (preferably about 30-60 degrees of a sphere) convex mirror


110


.




A security mirror of this type is generally not partially transparent, as required in the Invention, but is an ordinary convex mirror mounted in a circular channel frame with backing of, typically, masonite. The masonite is mounted in turn to an arm with, typically, a ball and socket joint for adjustment. The arm terminates at a mounting bracket so that it may be attached to a wall or ceiling.




In the preferred embodiment for this type of security mirror, a typical mirror blank is coated with a reduced amount of silvering (typically aluminum), as is known in the art, to create partially transparent mirror


110


. Roughly equal reflection and transmission are useful, but, where brightly lit spaces allow, lighter silvering is preferred. In any case, the Invention tolerates a rather wide range of silvering.




Typical circular channel frame


120


is used, without the masonite, to mount mirror


110


to a preferably conical housing


130


. Conical housing


130


, its large end being slightly smaller than the mirror


110


, engages the frame with flange


135


, flange


135


matching the diameter of mirror


110


. Flange


135


may be discontinuous.




Conical housing


130


may be of any durable material such as blow molded plastic or galvanized sheet steel. The inside of conical housing


130


is preferably matte black; the outside is preferably a neutral color so as to minimize its apparent size.




Typical mounting arm assembly


140


is attached, not to the (no longer present) masonite backing, but to the wall of conical housing


130


. Conical housing


130


provides for minimum restriction in mirror mounting position and orientation.




Conical housing


130


is preferably truncated at a plane coincident with center of curvature C of convex mirror


110


. At that distance, the small end of conical housing


130


is preferably about a quarter the diameter of mirror


110


.




To the small end of conical housing


130


is mounted, by ordinary means, lamp housing


200


, containing lamp or lamps


210


. Lamp


210


may be of any type. Transformers, batteries, ballasts, etc. (as needed) may be contained within or attached to lamp housing


200


or placed elsewhere. Lamp housing


200


may be vented.




A transparency


270


(or translucent image) of a circle


250


(preferably red with a black center and a black frame) is mounted in the front of lamp housing


200


(the side toward conical housing


130


). Where a red transparency


270


is used, the inside of lamp housing


200


is preferably white. A clear transparency


270


can be used to display a red circle if the interior of lamp housing


200


is red or if lamps


210


are red.




Preferred for economy, particularly for use with this first preferred embodiment, and particularly for use in brightly lit stores (where mirror silvering can be particularly thin), is light catcher


300


in place of lamp housing


200


. Basically a scoop (as shown in FIG.


3


), white inside or mirrored, light catcher


300


can be positioned beneath a ceiling fixture or anywhere under a generally illuminated ceiling. Even though an upward opening scoop is preferred, light catcher


300


can be open, or transparent or translucent in other or all directions (as shown in FIG.


4


).




It may be preferable, in a light catcher embodiment, to modify the color of the otherwise preferably red circle


250


, perhaps even tolwhite, in order to take fuller advantage of the ambient light.




The lamp housing


200


or light catcher


300


may be adjustably mounted. Adjustments parallel to the mirror can be used to more precisely position red circle


250


, preferably concentric with the center of curvature C of mirror


110


.




Adjustment toward mirror


110


will cause red circle


250


to lag behind as the viewer's image moves away from the center of mirror


110


. Adjustment away from mirror


110


will cause red circle


250


to lead the viewer's image as the image moves away from the center of mirror


110


. Such adjustment may be used intentionally for beneficial effects in some embodiments of the Invention or in other embodiments of the Patents incorporated herein.




In a preferred embodiment, lamp housing


200


or light catcher


300


is preferably red inside and has a circular aperture (preferably about one sixth the mirror diameter) facing the mirror. Preferably metal disk


350


is supported on bracket


320


, hidden behind (i.e. on the lighted side of) itself. Disk


350


is preferably black on the side facing mirror


110


and red on the back side. Bracket


320


is preferably red.




Disk


350


is smaller in diameter than housing


130


at that point so that a bright red ring around it is visible through mirror


110


. Metal disk


350


will be more durable and heat tolerant than the alternative transparency.




Also for durability, and for harsh or hazardous locations, the mirror itself may be formed from polished metal such as stainless steel, well known in some security mirror products. It is however required that the mirror be partially transparent. The mirror


111


is, therefore, formed from perforated stock or may be perforated as part of the forming process (by punching) or after forming (as by drilling).




Such a mirror


111


can be painted (or otherwise finished) matte black on its concave side to suppress unwanted reflections. This is a valuable structure for many uses of the diverse embodiments of the present Invention and of the other Patents incorporated herein by reference. Not only are miscellaneous reflections suppressed, but the ability of the concave side to focus collimated light is obviated. Mirrors of diverse materials can be manufactured by ordinary means to take advantage of these benefits of perforated mirrors.




SECOND PREFERRED EMBODIMENT




The second preferred embodiment


400


incorporates a hemispherical (or essentially hemispherical) mirror


410


.




A security mirror of this type is generally dropped through a hung ceiling and may be partially transparent, particularly for video surveillance through the mirror.




This type of mirror does not require the conical housing of the first preferred embodiment. Because the center of curvature C is roughly equivalent to the back edge of the mirror


410


, a simple flat cover


420


is preferred. Cover


420


has a central aperture, but generally prevents stray light (from above the ceiling) from entering the mirror.




At the center of cover


420


is mounted lamp housing


500


, similar to that in the first preferred embodiment. Horizontal hanger bar


430


is preferably provided to straddle the back edge of mirror


410


(above flat cover


420


) so that flat cover


420


need not support lamp housing


500


.




If the viewer moves far off the mirror's axis, two problems can appear. First, red circle


250


begins to appear more and more elliptical. Second, commercial mirror domes tend to have less accurate curvature away from the axis.




Fortunately, however, people walk on the floor and security mirrors are mounted at the ceiling. For that reason, the periphery of hemispherical mirror


410


is not used and an additional concentric area is active only for very distant viewers. Furthermore, hemispherical mirrors substantially reduce the size of images of the distant viewers.




For example, a six foot tall viewer, fifty feet from an eighteen inch radius dome mounted to a twelve foot ceiling, will see his/her image about 83 degrees off the axis of the mirror. However the image will be only about an inch tall, fairly indistinguishable at that distance. Moving in to twenty-five feet, the same viewer will see his/her two inch tall image about 77 degrees off the mirror axis. At twelve feet, the image will be about four and a quarter inches tall at about 63 degrees off the mirror axis. Figures for the same conditions with a twelve inch radius mirror are three quarters of an inch at 83 degrees, an inch and three eighths at 77 degrees and two and three quarter inches at 63 degrees.




These numbers are good enough to avoid problems due to mirror curvature, but red circle


250


may come to appear undesirably elliptical which would tend to reveal that red circle


250


is not actively tracking the viewer.




Therefore, lamp housing


200


of the first preferred embodiment


100


must be modified to protect the illusion. Lamp housing


500


of the second preferred embodiment


400


preferably has, protruding from it, hollow transparent globe


510


. The purpose and structure of hollow transparent globe


510


are described below.




Red Circles




It is important to recognize that a red circle is preferred, not mandatory. A circle is preferred for security mirrors to very definitely define the viewer's position while leaving a clear image of the viewer. Red is preferred as I believe it to be more intimidating for this purpose than other colors. Red is, however, more subtle than, say, adding crosshairs to the circle.




Additionally, the circle carries no meaningful size or other information to help the viewer distinguish the actual position of the circle in space. And the circle, although actually behind the viewer's image, interferes as if it were in front. That, and the compelling connection between a picture (the viewer's image) and its frame, all lend to the impression that the red circle is actively tracking the viewer.




Some of what follows is more useful or preferable in either the first preferred embodiment


100


or second preferred embodiment


400


or in other embodiments of the Invention or in other embodiments of the Patents incorporated herein.




The problem of the red circle appearing elliptical, with mirrors of the second preferred embodiment


400


, can be solved in different ways according to the requirements of the moment.




For the reasons stated above, a red circle is still the preferred image for both preferred security mirror embodiments. Furthermore, a red circle is easy to use in the first preferred embodiment


100


and it may be preferable to maintain the same image across a line of products incorporating both preferred embodiments.




A bright spherical object, at the center of curvature of the mirror, will appear through the mirror as a disk, regardless of the point of view. But a disk of light is not a circle and, although effective in tracking, will wash out the image of the viewer. To form the image of a circle, the center of the disk must be obscured. That would be easy if only one point of view was being addressed. But the disk is actually a sphere and the center must be obscured from any point of view, with the periphery, preferably always, remaining bright.




Preferably, hollow transparent globe


510


is positioned about the center of curvature C of mirror


410


. Globe


510


, which may be clear or tinted (preferably red), has an aperture at the top that is preferably formed by (or as if) cutting the globe horizontally. The top edge of globe


510


will, therefore, be flat. Flat edge


515


is then conveniently illuminated, preferably through a ring shaped aperture, from lamp housing


500


or a light catcher


300


.




Alternatively globe


510


may be formed with neck


530


at the top, neck


530


terminating in a flat, circular surface


515


. If neck


530


is incorporated it must be integral with globe


510


and the transition between the cylindrical shape of neck


530


and the spherical shape of globe


510


must be well faired (to avoid light leakage).




Since globe


510


is transparent, light is held within the globe wall by internal reflection and very little light is emitted from its inner or outer surface, except at flat top edge


515


. To obscure top edge


515


from view from below, black disk


525


can be positioned inside the top edge of globe


510


. It is preferred, however, to obscure the entire inner surface of globe


510


, which may be accomplished by, e.g., filling globe


510


with a black foam ball or painting the inside black.




To make globe


510


appear, from any point of view, as a bright circle, globe


510


is scored or grooved or drilled or etched (by ordinary means). The scoring, grooving, drilling, or etching pattern may be a multiplicity of (preferably equally spaced) meridians


535


. Internal reflection in the globe wall will thereby be disturbed and, as is well known in the art, meridians


535


will emit light. As dictated by well-known principles of geometry (and as shown in FIG.


7


B), meridians


535


will appear, when viewed generally horizontally, close together at the perceived edges of globe


510


and farther apart near the center.




It is preferred that each meridian


535


be obscured by a black mask


545


or painted over on the outside surface of the globe. Black mask


545


is broader than the underlying meridian


535


to obscure meridian


535


from a reasonably wide angle (about 60 degrees). Thus meridians


535


near the center of any generally horizontal view of the globe will be invisible through mirror


410


. Those at the edge of any horizontal view of globe


510


will not only appear, but will appear close together as a bright ring.




It is sometimes (as when space under mirror


410


is not accessible or when another mirror


410


“watches” the space) not necessary to accommodate views from the underside of mirror


410


. However, if desired, parallels


555


can also be added to the pattern to extend the illusion to all points of view. If parallels


555


are added, it is preferred to mask each parallel


555


with a ring


565


. Each ring


565


is preferably cylindrical, rather than conical, to obscure generally horizontal views of the associated parallel


555


while leaving parallel


555


visible to a viewer below. The series of parallels


555


is preferably terminated shortly north of the equator of the globe


510


, where the parallels


555


are no longer visible, through the wall of globe


510


, from below.




Meridians


535


and parallels


555


described above are preferred for some uses. A pattern that accomplishes a similar result with more consistent coverage from many angles is more generally preferred. The more generally preferred pattern can also be formed by scoring, grooving, drilling, or etching.




The more generally preferred pattern, actually a very large class of patterns, is a somewhat uniform, relatively fine (to appear, from a distance, to be essentially continuous) pattern, which may be a grid or dot pattern or a random stipple. The elements of the pattern preferably cover about fifty percent of the surface area of globe


510


. The pattern is then masked so it cannot be seen directly on the outside of globe


510


, but only through the opposite surface of globe


510


. The center of globe


510


being opaque, the generally illuminated surface of globe


510


thus appears as a bright circle.




Although not quite as bright (with similar illumination) as the scored, grooved, or etched globe, it is often preferred, particularly for economy, to use a smooth surfaced (i.e. not scored, grooved, drilled, or etched) transparent globe


510


and to apply paint or ink


560


of a light shade to take the place of the scoring, grooving, drilling, or etching. Where paint or ink


560


is applied, it will disturb the internal reflection in the transparent globe


510


and light will escape from the globe's surface.




A particular advantage of this approach is that the illuminated pattern, being essentially two-dimensional, can be masked by an essentially congruent dark pattern, rather than a dark pattern with larger elements (necessary to cover disparate viewing angles in more three-dimensional patterns).




Paint or ink


560


can be applied by any ordinary means such as manual brush painting, spraying, or silkscreen. White or red paint or ink


560


is preferred for the reasons discussed above. The pattern may be regular or irregular, but (although not absolutely necessary, because the outside surface of the pattern is not directly illuminated) should be covered with a congruent pattern of preferably matte black paint or ink


565


. The congruent pattern of dark paint or ink


565


can be created either by controlling the placement of the paint or ink, as in stenciling or silkscreen, or by allowing dark paint or ink


565


to adhere to the pattern of white or red paint or ink


560


and wiping it from the smoother surface of the preferably glass, transparent globe


510


. The latter technique can also be used and is particularly effective with a shallow etched pattern. The etched pattern can be overpainted with white or other light colored paint


560


and then overpainted with a mask of black or other dark paint or ink


565


.




A stippled pattern of sprayed paint (easy and economical to accomplish by reducing air pressure as is known in the art) can thus be used as the basic pattern (different for each individual globe). With such a stippled pattern, illuminated elements are seen through the “haze” of the dark pattern overlaying a different section of the stipple. This may be better appreciated by examining FIG.


13


.





FIG. 13

also shows how the thickness of the illuminated circle can be made greater than the actual thickness of transparent globe


510


. Rather than black painting the interior of globe


510


or filling the globe, dark (preferably matte black) sphere


600


, somewhat smaller than the interior of globe


510


and preferably of resilient material, such as synthetic rubber (so that it can be easily installed), is suspended inside of and concentric with globe


510


. This is most easily accomplished by providing dark sphere


600


with a plurality (or even a multiplicity) of protrusions


625


sufficient to contact the interior surface of globe


510


, thereby supporting dark sphere


600


.




Reflections between the concave face of mirror


410


and the polished surface of globe


510


can, if intrusive, be suppressed by ordinary means or by use of perforated mirror


111


disclosed above (here being extended to essentially a full hemisphere).




Tracking Without A Mirror




Although it is preferred to install the various embodiments of illuminated globe


510


into a hemispherical mirror


410


, globe


510


(or one of the other illuminated objects discussed herein) is useful as a stand-alone tracking device. An observer, seeing that an illuminated circle is turning to follow him/her, will believe that the circle is an active tracking device.




In fact, particularly where a mirror is not present, useful tracking devices need not be internally illuminated. Some configurations (such as that shown in FIG.


8


and discussed below) can be brightly colored on those surfaces that would ordinarily emit light.




Alternate Illuminated Objects




A similar effect to that of globe


510


can be achieved by constructing a globe


700


of thin fins


710


as meridians. Fins


710


are oriented with their greater cross sectional dimension toward the center of globe


700


. Each fin


710


preferably has a black mask


720


along the outer periphery and the center of globe


700


is preferably filled with black sphere


730


. Black mask


720


is intended to obscure fin


710


from a reasonably wide angle.




Fins


710


are preferably translucent on their broad surfaces. Light can be introduced into their preferably polished upper ends essentially as for transparent globe


510


disclosed above. Or fins


710


can be solid, preferably brightly colored, and illuminated externally by ordinary means. In either case, the effect is similar to that of transparent globe


510


, but without a polished surface to cause reflections. As discussed above, the latter embodiment is useful as a stand-alone tracking device.




A similar embodiment can be constructed by attaching a multiplicity of brightly colored, preferably cylindrical studs to a preferably spherical black core and applying a circular black mask to the protruding end of each stud. This will produce a more uniform circle.




Changing the shape of the core and/or the bright elements and/or the masks can produce a variety of useful embodiments. If, for example, the core is a vertical cylinder, bright elements such as described above will appear as two parallel bright vertical lines which will maintain their separation to a viewer moving around the apparatus. Bright rings around such a cylindrical array's top and bottom will result in the viewer seeing a rectangular tracking frame.




Alternatively, rotating light emitter


800


may be used to create the same effect. Ring


810


(or a vertically divided half ring), is rotatably suspended from above. Shaft


820


, which supports internally transparent ring


810


, is also transparent and integral with ring


810


. The flat surfaces of ring


810


are etched to emit light and black masks


830


are applied to the curved inner and outer surfaces.




Preferably, the top end of transparent shaft


820


is illuminated from lamp


210


(in a lamp housing) or from a light catcher. Motor


840


drives transparent shaft


820


at preferably several hundred revolutions per minute by ordinary linkage, such as gearset


850


. Spinning ring


810


will, therefore, be visible only when generally perpendicular to the direction from which it is viewed.




If viewing from below is expected, it is preferable to notch the outer surface of the ring, just below the equator. Right angle notches


860


with etched horizontal surfaces and black painted (or masked) vertical surfaces will appear as rings from below. Although, depending on masking, an angled view may introduce some ambiguity in the angle and position of the added ring, the overall effect will not be disturbed.




It may be preferred to provide a black shell


870


over ring


810


. Black shell


870


is provided with a multiplicity of holes


875


. The depth of each hole


875


in relation to its diameter will determine (by simple geometry) how much of the illuminated surface at the bottom of the hole can be seen from a particular viewing angle.




Masks or light baffles, to block certain lights from certain angles, are used effectively above. Light baffles, which might be large and attract attention if used in an open space, are particularly useful in embodiments of this Invention, and in embodiments of the Patents incorporated herein. In most embodiments of all of these inventions, dark objects behind the mirrors are invisible. In some cases it may be preferred to vignette the edges of baffles to soften the transition as a light appears from or disappears behind a baffle.




Baffles are used in a sometimes-preferred alternate to the globes disclosed above. Although this alternative may be illuminated in various ways, illumination from the top, from a lamp housing or light catcher by light conduction as disclosed above, is preferred.




An illuminated, flat red circle


251


, as preferred in the first preferred embodiment, is positioned about the center of curvature C of hemispherical mirror


410


. A cross-shaped aperture is preferably cut through the center of the face of lamp housing


201


with red circle


251


. Mounted into the face of lamp housing


201


is a light transmissive (such as acrylic) structure


15


in the shape of two planar members crossing at 90 degrees at the center of the circle. If this structure is actually made of two planar members (such as acrylic sheet), the joint(s) should be masked in black. Each of the four segments of transmissive structure


15


has, etched into each face of its inner corner (the one in contact with the center of the red circle), a 90-degree segment of a circle. Red circle


251


and each of the circle segments are of equal radius, preferably about one tenth to one fifth of the mirror diameter. The planes of transmissive structure


15


are preferably red, to match red circle


251


(or can be illuminated with red light). The balance of the surfaces of transmissive structure


15


are painted opaque black. These protruding surfaces are baffles to interfere with the view of parts of the illuminated circle segments from various angles.




In use, the viewer sees a red image which is, for most points of view, not a circle. The red image may, from many points of view, be interrupted in spots by parts of the baffling planar members. Nonetheless, the image is fairly economical to produce and, although its shape is somewhat plastic, it will not close up like an ellipse and will look reasonably the same from any point of view.




In some embodiments, it may be preferable to use a circular neon lamp or a pattern of light emitting diodes (LED's) as the red circle.




Bells & Whistles




The effect of the tracking mirror can be enhanced by modifying or adding elements to




Other two and three-dimensional shapes may be used as stand-ins for the red circle.




Fiber optics and light the preferred embodiment.




For example, in the first preferred embodiment


100


, disk


350


, which defines the center of red circle


250


, can be mounted to a (preferably about 30 rpm) motor


841


. Tab


351


, added to the edge of disk


350


, makes a gap in circle


250


, which revolves to suggest a radarlike device.




With a larger revolving disk


355


, having several apertures near the edge, the circle is replaced by a rotating ring of lights. Particularly if the disk is contoured, ambiguity of the light's actual position in space is enhanced, in some cases sufficiently for use in a hemispherical mirror


410


.conductive rods, holograms and lenticular screens can be used to advantage.




A particularly effective enhancement is to add a pair of screens


910


in front of red circle


250


(preferably close to red circle


250


, where they can be smaller). Screens


910


, which may be perforation patterns or printed on transparencies, create a moire effect, causing much activity in red circle


250


as the viewer changes location.




The circle itself and/or the globe of the second preferred embodiment can also be patterned to form part of the moire assembly.




While the Invention has been described with reference to preferred embodiments thereof, it will be appreciated by those of ordinary skill in the art that modifications can be made to the Invention and to its uses without departing from the spirit and scope thereof.



Claims
  • 1. An apparatus which appears to actively track the position of a viewer of the apparatus comprising:a three-dimensional, at least partially opaque core, defining the inside of the apparatus; image elements, disposed about the outside of the core, whereby an image pattern is formed; and mask elements, forming a mask pattern, corresponding to the image pattern, positioned essentially concentric with and outside the image pattern, whereby image elements viewed head-on are, to the viewer, essentially hidden by their respective mask elements and image elements viewed at some angles other than head-on are essentially visible to the viewer, thereby inducing the illusion that the visible image pattern is turning to track the viewer.
  • 2. The apparatus of claim 1, wherein the outside of the core is generally coincident with the inside of the image pattern.
  • 3. The apparatus of claim 1, wherein the outside of the core and the inside of the image pattern are spaced apart, so that image elements are visible through the space.
  • 4. The apparatus of claim 1, wherein the image pattern comprises a three-dimensional structure.
  • 5. The apparatus of claim 4, wherein the three dimensional structure comprises discontinuities in a transparent body.
  • 6. The apparatus of claim 1, wherein the image elements and mask elements are essentially two-dimensional.
  • 7. The apparatus of claim 1, also comprising:illumination means, disposed to illuminate the image elements.
  • 8. The apparatus of claim 1, also comprising:a partially transparent housing.
  • 9. The apparatus of claim 8, wherein the partially transparent housing comprises a partially reflective spherical mirror.
  • 10. The apparatus of claim 1, wherein the image elements and mask elements are successive positions of at least one typical image element and at least one typical mask element, disposed about the core by rapid displacement, the core being defined by the inside of the successive positions of the image elements.
  • 11. The apparatus of claim 1, also comprising:moiréscreens, positioned with the image pattern visible through them so as to induce an illusion of motion in the image pattern.
  • 12. An apparatus which appears to actively track the position of a viewer of the apparatus comprising:a spherical mirror; and an essentially circular image, with an open center, disposed essentially about the center of curvature of the spherical mirror.
  • 13. The apparatus of claim 12, wherein the essentially circular image is red.
  • 14. The apparatus of claim 12, also comprising:illumination means, disposed to illuminate the essentially circular image.
  • 15. The apparatus of claim 14, wherein the illumination means comprises a light catcher.
  • 16. The apparatus of claim 14, wherein the illumination means comprises a light source.
  • 17. The apparatus of claim 12, also comprising:a rotating mask, disposed to selectively obscure portions of the essentially circular image; and rotation means, operatively connected to rotate the rotating mask.
  • 18. The apparatus of claim 12, also comprising:moiréscreens, between the essentially circular image and the spherical mirror, with the essentially circular image visible through them so as to induce an illusion of motion in the circular image.
  • 19. The apparatus of claim 9, wherein the core, image elements, and mask elements are positioned about the center of curvature of the spherical mirror.
Parent Case Info

This application is based on my U.S. Provisional Patent Application No. 06/146,040, TRACKING MIRROR, filed Jul. 28, 1999, from which I claim priority.

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Number Name Date Kind
3634679 Krzyston Jan 1972 A
3651319 Norris et al. Mar 1972 A
3679888 Reiback Jul 1972 A
3772511 Marban Nov 1973 A
4164823 Marsico Aug 1979 A
4307528 Dewees et al. Dec 1981 A
4832453 Saad-Cook May 1989 A
5050056 Ellison Sep 1991 A
5214539 Sorko-Ram May 1993 A
5311335 Crabtree May 1994 A
5346433 Weinreich Sep 1994 A
5365378 Sorko-Ram Nov 1994 A
Provisional Applications (1)
Number Date Country
60/146040 Jul 1999 US