Abstract: Disclosed herein are devices that change their appearance and/or physical properties when under an external influence, and methods for their production and use. Such devices may be used as features of any type of items, documents, billboards, posters, display devices, advertisements and other items etc. and may be adapted to include decipherable content. Such devices also afford new techniques for a user to check quickly and easily whether the item is a legitimate or a counterfeit copy, either by hand-manipulation of the device, or with the assistance of an additional screening tool.

Abstract: Disclosed herein are devices that change their appearance and/or physical properties when under an external influence, and methods for their production and use. Such devices may be used as features of any type of items, documents, billboards, posters, display devices, advertisements and other items etc. and may be adapted to include decipherable content. Such devices also afford new techniques for a user to check quickly and easily whether the item is a legitimate or a counterfeit copy, either by hand-manipulation of the device, or with the assistance of an additional screening tool.

Abstract: Disclosed herein are devices that change their appearance and/or physical properties when under an external influence, and methods for their production and use. Such devices may be used as features of any type of items, documents, billboards, posters, display devices, advertisements and other items etc. and may be adapted to include decipherable content. Such devices also afford new techniques for a user to check quickly and easily whether the item is a legitimate or a counterfeit copy, either by hand-manipulation of the device, or with the assistance of an additional screening tool.

Abstract: Disclosed herein are devices that change their appearance and/or physical properties when under an external influence, and methods for their production and use. Such devices may be used as features of any type of items, documents, billboards, posters, display devices, advertisements and other items etc. and may be adapted to include decipherable content. Such devices also afford new techniques for a user to check quickly and easily whether the item is a legitimate or a counterfeit copy, either by hand-manipulation of the device, or with the assistance of an additional screening tool.

Abstract: Disclosed herein are devices that change their appearance and/or physical properties when under an external influence, and methods for their production and use. Such devices may be used as features of any type of items, documents, billboards, posters, display devices, advertisements and other items etc. and may be adapted to include decipherable content. Such devices also afford new techniques for a user to check quickly and easily whether the item is a legitimate or a counterfeit copy, either by hand-manipulation of the device, or with the assistance of an additional screening tool.

Abstract: An electrochromic variable optical attenuator having low insertion loss, and which is substantially insensitive to the polarization of optical signals transmitted therethrough, is disclosed. The attenuator includes an annular working electrode, and a counter electrode surrounding and spaced from the annular working electrode in a coplanar configuration. Also included is an electrochromic layer in peripheral contact with the annular working electrode; and a further electrochromic layer overlying the counter electrode. An electrolyte overlies and is in contact with the two electrochromic layers; so that upon application of an electrical voltage between the electrodes, the optical density of the electrochromic layer is altered, thereby varying the attenuation of incident optical signals transmitted therethrough.

Abstract: An electronic phase shifter splits an input signal into two signals whose amplitudes are set by a weighting circuit controlled by a phase shift control signal. Each of the two outputs of the weighting circuit is loaded with an RLC resonator, one tuned to a frequency lower than that of the input signal and one tuned to a frequency higher than that of the input signal. The loaded outputs are recombined in a vector summing network to synthesize the required phase shifted output signal. This technique permits implementation on a monolithic integrated circuit (MIC) with high gain at high frequencies (e.g. 10 GHz). It also allows a large dynamic range of operation and a large (i.e., greater than 90 degrees) controllable phase shift. This is accomplished without the use of variable reactance elements or any other components external to the MIC.