Abstract: A combination magnetic tag (10) is described comprising an optical part (20) and a magnetic part (30), the optical part including a plurality of optical elements for conveying an optical code and the magnetic part including a plurality of magnetic elements for conveying a magnetic code, the optical and magnetic codes being mutually complementary for verifying authenticity of the tag (10). Incorporation of both optical and magnetic codes into the tag is of advantage in that they are capable of rendering the tag less susceptible to copying. The tag (10) is relevant to appropriate to anti-counterfeiting applications.

Abstract: There is described a programmable tag susceptible to magnetic interrogation using an interrogating magnetic field, the tag comprising: (a) a plurality of saturable magnetic structures (310) for non-linearly coupling the interrogating magnetic field into a corresponding response magnetic field; (b) reversibly programmable magnetic regions (330) for applying offset magnetic fields to the magnetic structures for modifying their non-linear coupling characteristics. The tag is susceptible to being mass-produced from a continuous strand of tag material severed to produce individual tags. The tag is of advantage in that it can be reversibly programmed. There is also described a method of recording data on the tag, the method including the steps of: (c) bringing the tag in close proximity to a recording apparatus; and (d) applying a magnetising magnetic field to each of the magnetic regions (330) for modifying a magnetic field retained therein to which its associated saturable structure is subjected.

Abstract: A combination magnetic tag (10) is described comprising an optical part (20) and a magnetic part (30), the optical past including a plurality of optical elements for conveying an optical code and the magnetic part including a plurality of magnetic elements for conveying a magnetic code, the optical and magnetic codes being mutually complementary for verifying authenticity of the tag (10). Incorporation of both optical and magnetic codes into the tag is of advantage in that they are capable of rendering the tag less susceptible to copying. The tag (10) is relevant to appropriate to anti-counterfeiting applications.

Abstract: A method of and apparatus for scale factor compensation for piezo-electric rate sensors maintains the magnitude of vibration at a primary pick-off point substantially constant to enable one of the variables of a vibrating structure--the piezo-electric charge coefficient .beta. to be determined, and thereby enables variation of the scale factor of the sensor from a calibrated value to be determined. This enables correction of the sensor output by a computational scale factor control unit to ensure that the output therefrom allows for a more accurate sensor. Thus, sensors are provided for applications requiring a higher degree of accuracy than they were previously able to provide for.

Abstract: The method comprises the steps of providing a substrate wafer (10); depositing a first layer of resist (12) upon the substrate wafer (10); removing selected areas of the first resist layer (12), thereby to provide first etch windows; forming first cavities (16) in the substrate wafer (10) by a first etching process through the first windows; bonding a relatively thick membrane wafer (24) to the substrate wafer (10), thereby covering the cavities (16); polishing the surface of the relatively thick membrane wafer (24) thereby to produce a relatively thin membrane (24a); depositing a second layer of resist (33) on the relatively thin membrane (24a); removing selected areas of the second deposited resist layer, thereby to provide second etch windows (40); etching away the relatively thin membrane (24a) in the region of the second etch windows (40) until the first cavities (16) are exposed, thereby to form in the relatively thin membrane (24a) a free standing resonator structure (18 ) suspended on a plurality of c

Abstract: A vibrating planar ring or hoop-like structure is disclosed. The structure is suspended in space by a suitable support mount for detecting turning rate, linear acceleration and angular acceleration. Turning rate is sensed by detecting vibrations coupled by Coriolis forces, whereas linear acceleration and angular acceleration are sensed by lateral, vertical and rocking movement of the entire ring or hoop-like structure within its mount.

Abstract: This invention relates to a single axis solid state attitude sensor in which, the spatial orientation of a resonant rode on a resonant body is maintained in alignment with the inertial angle K8 of the resonant body.