A security device includes a diffractive structure, including grating elements and having a first area, the grating elements within a region have a constant pitch or spacing; the first area regions pitches or spacings increase from one region to the next between a first region having a grating element pitch or spacing of less than or equal to 0.6 microns and an end region having a grating element pitch or spacing of greater than or equal to 5 microns; upon illumination and viewing along a first viewing direction substantially orthogonal to the first axis, the device exhibits a first optical effect in that at least one region exhibits a diffractive colour; each region has at least first and second sub-regions having different grating element orientations within the plane of the device such that the first optical effect is exhibited at more than one angle of tilt about the second axis.

A security device includes a diffractive structure, including grating elements and having a first area, the grating elements within a region have a constant pitch or spacing; the first area regions pitches or spacings increase from one region to the next between a first region having a grating element pitch or spacing of less than or equal to 0.6 microns and an end region having a grating element pitch or spacing of greater than or equal to 5 microns; upon illumination and viewing along a first viewing direction substantially orthogonal to the first axis, the device exhibits a first optical effect in that at least one region exhibits a diffractive colour; each region has at least first and second sub-regions having different grating element orientations within the plane of the device such that the first optical effect is exhibited at more than one angle of tilt about the second axis.

A multilayer identification patch comprises a reflective layer and a design layer on top of the reflective layer. The design layer comprises an opaque body and at least one identification symbol void (ISV) to allow light to reflect from a portion of the reflective layer via the ISV. The opaque body of the design layer comprises multiple layers of cured photopolymer ink. The multiple layers of cured photopolymer ink comprise an opaque layer of colored photopolymer ink. In one embodiment, the multiple layers of cured photopolymer ink in the opaque body of the design layer further comprise a layer of clear photopolymer ink under the opaque layer of colored photopolymer ink. Other embodiments are described and claimed.

A multilayer identification patch comprises a reflective layer and a design layer on top of the reflective layer. The design layer comprises an opaque body and at least one identification symbol void (ISV) to allow light to reflect from a portion of the reflective layer via the ISV. The opaque body of the design layer comprises multiple layers of cured photopolymer ink. The multiple layers of cured photopolymer ink comprise an opaque layer of colored photopolymer ink. In one embodiment, the multiple layers of cured photopolymer ink in the opaque body of the design layer further comprise a layer of clear photopolymer ink under the opaque layer of colored photopolymer ink. Other embodiments are described and claimed.

A method of manufacturing a security device including: conveying a substrate web including a photosensitive film along a transport path; exposing the photosensitive film to radiation of a predetermined wavelength through a mask, wherein the mask includes a predetermined pattern of regions which are substantially opaque to radiation of the predetermined wavelength and at least semi-transparent to radiation of the predetermined wavelength, respectively; during the exposure, moving the mask alongside the substrate web along at least a portion of the transport path at substantially the same speed as the substrate web, such that there is substantially no relative movement between the mask and the substrate web; and heating the substrate web including the exposed photosensitive film. In this way, regions of the photosensitive film exposed to the radiation of the predetermined wavelength undergo an increase in optical density such that the photosensitive film displays a reproduction of the predetermined pattern.

A method of manufacturing a security device including: conveying a substrate web including a photosensitive film along a transport path; exposing the photosensitive film to radiation of a predetermined wavelength through a mask, wherein the mask includes a predetermined pattern of regions which are substantially opaque to radiation of the predetermined wavelength and at least semi-transparent to radiation of the predetermined wavelength, respectively; during the exposure, moving the mask alongside the substrate web along at least a portion of the transport path at substantially the same speed as the substrate web, such that there is substantially no relative movement between the mask and the substrate web; and heating the substrate web including the exposed photosensitive film. In this way, regions of the photosensitive film exposed to the radiation of the predetermined wavelength undergo an increase in optical density such that the photosensitive film displays a reproduction of the predetermined pattern.

A sheet assembly can be cut into one or more cards. The sheet assembly includes an upper sheet configured to receive a first printing of first indicia for the one or more cards, a polymer core coupled with the upper sheet, and a lower sheet configured to receive a second printing of second indicia for the one or more cards. The lower sheet is coupled with the polymer core with the polymer core disposed between the upper sheet and the lower sheet. The upper sheet, polymer core, and/or the lower sheet is or are formed from a polymer binder with inorganic particles dispersed in the polymer binder. The inorganic particles can have a first density of the inorganic particles that is less than four times a second density of the polymer binder and/or a mass-median-diameter (D.sub.50) of the inorganic particles can be larger than ten microns in size.

A sheet assembly can be cut into one or more cards. The sheet assembly includes an upper sheet configured to receive a first printing of first indicia for the one or more cards, a polymer core coupled with the upper sheet, and a lower sheet configured to receive a second printing of second indicia for the one or more cards. The lower sheet is coupled with the polymer core with the polymer core disposed between the upper sheet and the lower sheet. The upper sheet, polymer core, and/or the lower sheet is or are formed from a polymer binder with inorganic particles dispersed in the polymer binder. The inorganic particles can have a first density of the inorganic particles that is less than four times a second density of the polymer binder and/or a mass-median-diameter (D.sub.50) of the inorganic particles can be larger than ten microns in size.

A credit card with an obscurable account identifier. The credit card further comprises a substrate defining a first surface with a chromogenic feature wherein the chromogenic feature is capable of changing from a first state and a second state based on an activating trigger. In the first state, the chromogenic feature appears with a first optical property that obscures the account identifier, and in the second state, the chromogenic feature appears with a second optical property that reveals the account identifier.

A multilayer identification patch comprises a reflective layer and a design layer on top of the reflective layer. The design layer comprises an opaque body and at least one identification symbol void (ISV) to allow light to reflect from a portion of the reflective layer via the ISV. The opaque body of the design layer comprises multiple layers of cured photopolymer ink. The multiple layers of cured photopolymer ink comprise an opaque layer of colored photopolymer ink. In one embodiment, the multiple layers of cured photopolymer ink in the opaque body of the design layer further comprise a layer of clear photopolymer ink under the opaque layer of colored photopolymer ink. Other embodiments are described and claimed.