Abstract: A multilayered composite product useful as an electrical circuit is produced by coating a base with a photoimagable resin free of catalyst or catalyst activator for electroless metal deposition. The resin is patterned by exposure to a desired light, through a mask followed by development. The patterned cured resin is selectively chemically modified while avoiding chemical modification of the base to render the cured resin receptive to a metal catalyst. The metal catalyst which promotes subsequent electroless metal deposition is selectively absorbed on the patterned cured resin and is converted to a catalytically active form. A conductive metal then is deposited selectively on the catalyst-containing patterned cured resin.

Abstract: A resonant tag circuit is provided which is useful in conjunction with an electronic security system for preventing theft of articles from a protected area. The tag circuit comprises an electrically insulating substrate having a spiral conductive path on each surface of the substrate. The spiral conductive paths are positioned to overlap each other to effect distributed capacitance. The degree of overlap of the distributed capacitance portion of the conductive paths is such that it provides at least 70%, preferably 90% and most preferably 100% of the total overlapping portions of the circuit.

Abstract: A process is provided for fabricating metallic patterns such as resonant RF-tuned circuits on a polyolefin film such as polyethylene or polypropylene film. The film is processed under conditions such as to maintain its mechanical integrity by being passed through a solvent plasticizing bath, an etch bath to provide attraction sites and adhesion for catalytic metal deposition, a conditioning bath to improve catalyst adhesion and a catalyst bath to deposit a catalytic metal for electroless metal deposition. A negative image is printed on the film and an electroless metal deposit followed by an electrolytic metal plate are applied to the film to produce the desired metallic patterns. Optionally, prior to the printing step, an electroless metal deposit, with or without a thin electrolytic metal plate, can be applied to the total film surface. Thereafter, a negative or positive printed image is coated on the film.

Abstract: A multilayered composite product including a base, a patterned cured resin bonded to the base and an applied metal layer selectively bonded to the patterned cured resin. The product is useful as an electrical circuit.

Abstract: The secure release apparatus is used with an anti-theft device having a member which is movable in response to an applied magnetic field. The secure release apparatus comprises a cover plate with an access opening and a permanent magnet structure which produces a concentrated magnetic field sufficiently strong to move the member. A tamper prevention structure is movable into a first position for preventing the member from moving into the concentrated field.

Abstract: The system includes a transmitter producing an electromagnetic field at a frequency repetitively swept through a predetermined range at a predetermined sweep frequency. A receiver senses a resonant frequency produced by a resonant tag circuit when the tag circuit is within the electromagnetic field and produces an output signal in response to the resonant frequency. A first noise rejection circuit is provided which accepts the output of the receiver and produces a pulse in response to selected output signals from the receiver. The selected output signals include an initial output signal and successive output signals which occur at an interval from the previous selected output signal which is at least as great as the period of the sweep frequency. The circuit then compares the frequency of the pulses produced with the sweep frequency and produces an alarm signal when the pulse frequency and sweep frequency are substantially equal.

Abstract: Disclosed is a loop antenna for the propagation of electromagnetic radiation with minimal electrostatic radiation for use in security systems. At least a single loop of conductor forms the radiating surface of the antenna. However, the loop is disposed in a tubular electrostatic shield which serves to minimize electrostatic radiation while not significantly interfering with the desired electromagnetic radiation. In preferred embodiments the electrostatic shield may be electrically grounded or a resistor may be placed in the conduction loop of the antenna to broaden the frequency response thereof. Additional preferred embodiments include twisting the single loop antenna one or more times such that two or more lobes are provided forming a twisted loop antenna. Far-field cancellation of transmitted signals is achieved and there is self cancellation in this antenna of received common mode signals.

Abstract: An insulative substrate web having a conductive surface on a first face is printed and etched to provide a repetitive conductive circuit pattern. In one form of the invention, the pattern defines a first conductive area serving as a first capacitor plate, and an inductor connected thereto; conductive material is applied to the second face of the web to define a second conductive area aligned with the first conductive area and serving as a second plate of the capacitor, and a conductive strip connecting the second conductive area to the other end of the inductor. In another form of the invention, the pattern defines first and second conductive areas connected by an inductor; the web is folded so that the conductive areas are aligned to form respective plates of a capacitor. The web may form the capacitor dielectric, or an insulative layer may be inserted for this purpose; and the web is sealed to fix the capacitance. The web is severed to provide individual planar resonant tags.

Abstract: An electronic security system utilizing a transmitter and receiver in combination with a resonant tag circuit which is responsive to at least one frequency of electromagnetic radiation. The transmitter provides electromagnetic radiation in a predetermined area at a frequency close to the resonant frequency of the resonant tag circuit. The transmitter additionally modulates its frequency with a detection modulation frequency F.sub.d. The receiver is responsive to electromagnetic radiation and picks up at least a component of the detection modulation frequency F.sub.d. In a preferred embodiment, this component is an AM signal radiated by the resonant tag circuit when the tag circuit is in turn activated by the frequency modulated transmitter frequency. A detection logic circuit responsive to the presence of AM signal at frequency F.sub.d, signals an appropriate alarm.

Abstract: A locking device which includes a housing, a spring biased insert, arcuately spaced retaining balls, and cup means which is securely mounted in the housing and retains the balls and the lower end of the insert. The tapered side walls of the cup means provide a cam surface upwardly along which the balls can move when a pin is inserted in the lock. When the pin is released the balls tightly frictionally engage the pin under the bias of the spring, thereby preventing unauthorized removal of the pin.

Abstract: A fastening device for securing articles together, the device including releasably connected male and female components. The male component comprises a pin and the female component comprises a retaining insert positioned in a housing for releasably clamping the pin. When joined, the pin can not be separated from the retainer except by a special tool. The insert is of magnetic material, and an actuating tool including an electromagnet is employed to actuate the insert to permit removal of the pin. The housed insert is attached to a tag, with the tag being attached to the article which is to be sold. The tag houses an electrical circuit which activates an alarm if the tag is not properly removed at the checkout point by means of the special tool.

Abstract: A fastening device for securing articles together, the device including releasably connected male and female components. The male component comprises a pin and the female component comprises a retaining insert positioned in a housing for releasably clamping the pin. When joined, the pin can not be separated from the retainer except by a special tool. The insert is of magnetic material, and an actuating tool including an electromagnet is employed to actuate the insert to permit removal of the pin. The housed insert is attached to a tag, with the tag being attached to the article which is to be sold. The tag houses an electrical circuit which activates an alarm if the tag is not properly removed at the checkout point by means of the special tool.

Abstract: A fastening device for securing articles together, the device including releasably connected male and female components. The male component comprises a pin and the female component comprises a retaining insert positioned in a housing for releasably clamping the pin. When joined, the pin can not be separated from the retainer except by a special tool. The insert is of magnetic material, and an actuating tool including an electromagnet is employed to actuate the insert to permit removal of the pin. The housed insert is attached to a tag, with the tag being attached to the article which is to be sold. The tag houses an electrical circuit which activates an alarm if the tag is not properly removed at the checkout point by means of the special tool.