Abstract: A security device that exhibits at least one dynamic response upon change of orientation of the security device with respect to gravity, wherein the security device includes a hollow capsule completely filled with a liquid and one or more microscopic elements. In addition, the dynamic response continues after cessation of the change of orientation with respect to gravity. The dynamic response includes a transition of the one or more microscopic elements from substantial mechanical equilibrium to non-equilibrium upon action of the change of orientation with respect to gravity and back to substantial mechanical equilibrium after cessation of the change of orientation with respect to gravity. During the dynamic response, the one or more microscopic elements undergo at least one of a rotational motion and a translational motion relative to the liquid.

Abstract: Security documents often incorporate security devices to prevent or hinder counterfeiters. Disclosed herein are security devices that include a fluid or fluids within the devices. Such devices, and security documents that include them, afford new techniques to check whether a security document is a legitimate or counterfeit copy.

Abstract: A security device that exhibits at least one dynamic response upon change of orientation of the security device with respect to gravity, wherein the security device includes a hollow capsule completely filled with a liquid and one or more microscopic elements. In addition, the dynamic response continues after cessation of the change of orientation with respect to gravity. The dynamic response includes a transition of the one or more microscopic elements from substantial mechanical equilibrium to non-equilibrium upon action of the change of orientation with respect to gravity and back to substantial mechanical equilibrium after cessation of the change of orientation with respect to gravity. During the dynamic response, the one or more microscopic elements undergo at least one of a rotational motion and a translational motion relative to the liquid.

Abstract: A security device that elicits at least one dynamic response upon acceleration, or upon change of orientation with respect to gravity, wherein the dynamic response continues after cessation of the acceleration or the change of orientation. In addition, the dynamic response can be optical, such that it is visually observable by an unaided human eye. Alternatively, the response can be machine readable. In some cases, the dynamic response has duration of from about 0.01 s to about 100 s, or from about Is to about 10 s.

Abstract: Security documents often incorporate security devices to prevent or hinder counterfeiters. Disclosed herein are security devices that include a fluid or fluids within the devices. Such devices, and security documents that include them, afford new techniques to check whether a security document is a legitimate or counterfeit copy.

Abstract: Security documents often incorporate security devices to prevent or hinder counterfeiters. Disclosed herein are security devices that include a fluid or fluids within the devices. Such devices, and security documents that include them, afford new techniques to check whether a security document is a legitimate or counterfeit copy.

Abstract: Gravitational Janus microparticle having, a center-of-mass, a center-of-volume, and a non¬uniform density, wherein: the center-of-mass and the center-of-volume are distinct. When suspended in a fluid, the microparticle substantially aligns with either: i) the gravitational field; or ii) the direction of an acceleration, such that the Janus microparticle is in substantial rotation equilibrium. After perturbation from substantial rotational equilibrium, the Janus microparticle reversibly rotates to return to substantial rotational equilibrium. The gravitational Janus microparticle may comprise at least two portions, each having distinct physical and/or chemical characteristics, wherein at least one portion provides a detectable effect following rotation and alignment of the microparticle.

Abstract: Magnetic ink and toner compositions traditionally comprise magnetic materials in fine particulate form, either as a dry composition or a liquid suspension. Often such materials are black or dark in color. Disclosed herein are particles compositions suitable for use as inks or toners, that exhibit desirable magnetic properties, and furthermore which include particles coated so they appear white substantially white, or colored. Such compositions present new opportunities for the production of corresponding magnetic layers, when the compositions are deposited in an appropriate manner to a substrate.

Abstract: Security documents often incorporate security devices to prevent or hinder counterfeiters. Disclosed herein are security devices that include a fluid or fluids within the devices. Such devices, and security documents that include them, afford new techniques to check whether a security document is a legitimate or counterfeit copy.

Abstract: A security device that elicits at least one dynamic response upon acceleration, or upon change of orientation with respect to gravity, wherein the dynamic response continues after cessation of the acceleration or the change of orientation. In addition, the dynamic response can be optical, such that it is visually observable by an unaided human eye. Alternatively, the response can be machine readable. In some cases, the dynamic response has duration of from about 0.01 s to about 100 s, or from about Is to about 10 s.

Abstract: Gravitational Janus microparticle having, a center-of-mass, a center-of-volume, and a non-uniform density, wherein: the center-of-mass and the center-of-volume are distinct. When suspended in a fluid, the microparticle substantially aligns with either: i) the gravitational field; or ii) the direction of an acceleration, such that the Janus microparticle is in substantial rotation equilibrium. After perturbation from substantial rotational equilibrium, the Janus microparticle reversibly rotates to return to substantial rotational equilibrium. The gravitational Janus microparticle may comprise at least two portions, each having distinct physical and/or chemical characteristics, wherein at least one portion provides a detectable effect following rotation and alignment of the microparticle.

Abstract: Security documents often incorporate security devices to prevent or hinder counterfeiters. Disclosed herein are security devices that include a fluid or fluids within the devices. Such devices, and security documents that include them, afford new techniques to check whether a security document is a legitimate or counterfeit copy.

Abstract: An optical based authentication device that is attachable to a security document having a substrate. The authentication device includes: a piezoelectric material layer for generating an electric field in response to mechanical stress; and an optically responsive layer directly attached to the piezoelectric material layer, the attached layers being absent a direct electrical connection, the optically responsive layer being operable between a first state and a second state having different ocular perceptions. The optically responsive layer changes from the first state to the second state in response the electric field generated by the piezoelectric material layer.

Abstract: An optical based authentication device that is attachable to a security document having a substrate. The authentication device includes: a piezoelectric material layer for generating an electric field in response to mechanical stress; and an optically responsive layer directly attached to the piezoelectric material layer, the attached layers being absent a direct electrical connection, the optically responsive layer being operable between a first state and a second state having different ocular perceptions. The optically responsive layer changes from the first state to the second state in response the electric field generated by the piezoelectric material layer.

Abstract: Security documents often incorporate security devices to prevent or hinder counterfeiters. Disclosed herein are security devices that include a fluid or fluids within the devices. Such devices, and security documents that include them, afford new techniques to check whether a security document is a legitimate or counterfeit copy.

Abstract: Magnetic ink and toner compositions traditionally comprise magnetic materials in fine particulate form, either as a dry composition or a liquid suspension. Often such materials are black or dark in colour. Disclosed herein are particles compositions suitable for use as inks or toners, that exhibit desirable magnetic properties, and furthermore which include particles coated so they appear white substantially white, or coloured. Such compositions present new opportunities for the production of corresponding magnetic layers, when the compositions are deposited in an appropriate manner to a substrate.