Abstract: A tuned resonant circuit including inductive and capacitive components useful as a marker in electronic article surveillance systems, comprising a laminate of a dielectric sheet having a conductive layer on one side configured to form at least one multi-turn inductive spiral. The sheet is folded back upon itself at a fold line which is precisely defined by spaced apart areas of the conductive layer such that desired portions of the layer become precisely and uniformly juxtaposed.

Abstract: The novel optical recording medium, as in the prior art, has a transparent substrate bearing two recording layers, each addressable from only one side of the medium, but unlike prior 2-sided media, the two recording layers are on the same face of the substrate. When the novel medium is addressed from one side of the substrate, a thin-film barrier, such as an opaque metal, between the two recording layers prevents the more distant recording layer from responding to that energy. Preferably a tough, transparent cover layer is sealed to the substrate to protect the two recording layers.

Abstract: An electronic article surveillance system is disclosed, having a transmitter means for producing in an interrogation zone sequences containing a plurality of discrete different radio frequencies thereby causing a circuit present within the zone to resonate at its resonant frequency in response to energy absorbed at at least three different frequencies. A receiver means is provided to cause an alarm in the event of detection of three such resonances over two successive sequences.

Abstract: Cassette recorder has a spring member which fits into a depression in the rear edgewall of a cassette to sense whether the cassette is properly positioned for recording. The depression preferably is a conical receptacle, and the spring member has a rounded pawl which fits into the receptacle. The spring member also forces the cassette forwardly against a pair of positioning pins which have inclined faces to force the front of the cassette against the base plate of the recorder thereby positively positioning the cassette in place, and means connected to the spring member enable recording only when the member is fully seated into the depression.

Abstract: A synchronization circuit for a free-running oscillator, in which a multi-tapped delay line provides delayed outputs incrementally spaced throughout the period and at the same frequency as the oscillator. That delayed signal closest in time to a reference signal is selected as the output signal, synchronized to the reference signal.

Abstract: An electronic article surveillance system and a marker for use therein, which marker comprises a tuned resonant circuit including inductive and capacitive components formed of a laminate of a dielectric and conductive-multi-turn spirals on opposing surfaces of the dielectric, wherein the capacitive component is formed as a result of distributed capacitance between the opposed spirals, and wherein the circuit thereby resonates at at least two predetermined frequencies which are subsequently received to create an output signal.

Abstract: A standardized document such as a credit card has a thin, light-transmissive, electrically conductive interior layer, the impedance, capacitance, or conductance of which can be sensed to indicate the authenticity of the document. When the document is cut to expose a new edge, the authenticating layer at that edge is not visible to the naked eye and hence should foil the ordinary counterfeiter.

Abstract: A connector for an optical fiber cable is disclosed wherein strain relief features are provided for minimizing strain applied either to the external jacket of the cable or to the fiber such as during connecting operations is prevented from being coupled to the optical fiber. The connector thus includes strain relief members for securely anchoring the outer jacket of the cable and for anchoring strain relief fibers contained within the cable. Also, a resilient member is provided for allowing limited rearward movement of a member within which the optical fiber is anchored such as may occur during connection.

Abstract: In a tape which is driven by an elastic pretensioned belt, discontinuities such as embossings in the surface of the belt promote the release of air from between the belt and the underlying tape, thus minimizing variations in tape tension and tape speed.

Abstract: A marker adapted to be used with cloth or fabric articles to enable the detection thereof in an electromagnetic article surveillance system within which the marker generates a detectable signal related to an alternating electromagnetic field applied within an interrogation zone, wherein the marker comprises an elongated strip of amorphous ferromagnetic ribbon sealed on all major surfaces within flexible polymeric cover layers having a low rate of water vapor transmission, and a high degree of thermal stability, puncture resistance and conformability, such that the articles having the marker included therein may be subjected to repeated flexing and high temperature and humidity conditions such as encountered in commercial laundry operations without affecting the magnetic properties of the marker, while also not appreciably stiffening the article itself, thus being readily attached to or concealed therein.

Abstract: A standardized document such as a credit card or drivers license contains an electrically conductive authenticating layer which is not visually discernible and has an electrical resistivity of less than 50 megohms per square. The presence of the authenticating layer may be verified by a proximity switch that can be built into mechanisms normally used in processing the document.

Abstract: A tuned resonant circuit including inductive and capacitive components useful as a marker in electronic marker surveillance systems, comprising a laminate of a dielectric and conductive-multi-turn spirals on opposing surfaces of the dielectric, wherein the capacitive component is formed as a result of distributed capacitance between the opposed spirals, and wherein an electrical connection is provided between predetermined opposing portions of the respective spirals.

Abstract: Recording tape cassette has pivotable spring means including a record-lockout tab which blocks an opening when the spring means is cocked. When placed on a cassette deck, a fixed tang on the deck releases the cocking, allowing the spring means and its record-lockout tab to pivot to a retracted position, thus unblocking the opening. Thereafter, a feeler on the deck can enter that opening to disable the record function.

Abstract: Optical recording medium having a laser-recordable light-absorbing layer which is a carbide of iron or chromium has surprisingly high sensitivity. High carrier-to-noise ratios are attained using a laser-diode recording system at power levels below 10 mW.

Abstract: A method of constructing an LC network, and the resulting LC network manufactured by cutting and removing a predetermined pattern from a first and a second conductive sheet, leaving on each sheet a generally coil-like configuration of windings with a sufficient number of interconnections between the adjacent windings to add rigidity to the sheets, laminating these conductive sheets to opposing faces of a non-conductive sheet, thereby forming at least one capacitor, cutting and removing a pre-determined pattern from the lamination eliminating at least some of the interconnections and leaving a conductive path on the conductive sheets which is in the configuration of a coil.

Abstract: Quadrilayer optical DRAW medium which differs from prior trilayer optical DRAW media by having a thin triggering layer adjacent each of the optical spacer and light-absorbing layers. The triggering layer is a material, preferably organic, which when heated by a modulated laser-diode beam to a temperature less than the melting point of the optical spacer layer develops substantial vapor pressure or otherwise rapidly expands to implement or enhance the formation of pits or bubbles in the light-absorbing layer without disturbing the optical spacer layer or its function of protecting the substrate of the medium.

Abstract: A method of making electrical connections between metal foils laminated to opposing surfaces of a flexible insulating layer, such as may be configured with spiral patterns in the respective metal foils to form inductive-capacitive circuits useful as detectable markers in RF antipilferage systems, and wherein an electrical connection is provided between the opposing foils by first extruding the laminate to shear the insulating layer and to contact the opposing metal foils in the vicinity of the sheared insulator layer and by subsequently forcing the extrusion back into a substantially planar relationship relative to the remainder of the laminate.

Abstract: An optical recording medium containing a light-absorbing film of refractory material less than 60 nm thick and selected from carbides of Al, Hf, Nb, Ta, Ti, V, W, and Zr and alloys herebetween, whereupon localized heating of the light-absorbing film enables information storage in the form of localized features in the heated areas which can subsequently be optically detected and can be used as a master information record for replication purposes.

Abstract: An electronic article surveillance system is disclosed, having a transmitter means for producing in an interrogation zone sequences containing a plurality of discrete different radio frequencies thereby causing a circuit present within the zone to resonate at its resonant frequency in response to energy absorbed at at least three different frequencies. A receiver means is provided to cause an alarm in the event of detection of three such resonances over two successive sequences.

Abstract: A thin-film magnetic recording playback head is disclosed wherein mechanically coupled films of a magnetostrictive material and of a piezoelectric material are deposited on a substrate together with a solid state amplifier which is coupled to the piezoelectric film. In operation, localized magnetic patterns on a recording medium induce stress in the magnetostrictive film, which in turn induces in the piezoelectric film a corresponding electrical polarization of non-equilibrium charge density, having a potential associated therewith which is applied to the solid state amplifier.