The invention relates to an anti-copy optical element comprising a caustic layer and a mask layer configured to simultaneously display a visible image reproducing a reference image and form a projected image containing a visible caustic pattern reproducing a reference pattern, upon illumination of the optical element with a light source, the projected image being distinct from the reference image. The invention also relates to a method for designing a relief pattern of a light-redirecting surface of said caustic layer consistently with the transmission properties of the mask layer.

The invention relates to an anti-copy optical element comprising a caustic layer and a mask layer configured to simultaneously display a visible image reproducing a reference image and form a projected image containing a visible caustic pattern reproducing a reference pattern, upon illumination of the optical element with a light source, the projected image being distinct from the reference image. The invention also relates to a method for designing a relief pattern of a light-redirecting surface of said caustic layer consistently with the transmission properties of the mask layer.

A micro-optic security device with zonal color transitions includes a planar array of focusing elements, an image icon layer including a plurality of retaining structures, the plurality of retaining structures defining isolated volumes at a first depth within the image icon layer, a first zone of image icons, the first zone of image icons having a first predefined subset of the plurality of retaining structures, wherein the isolated volumes of retaining structures of the first predefined subset of the plurality of retaining structures contain cured pigmented material of a first color, and a second zone of image icons, the second zone of image icons including a second predefined subset of the plurality of retaining structures, wherein the isolated volumes of retaining structures of the second predefined subset of the plurality of retaining structures contain cured pigmented material of a second color, wherein the second color contrasts with the first color.

A micro-optic security device with zonal color transitions includes a planar array of focusing elements, an image icon layer including a plurality of retaining structures, the plurality of retaining structures defining isolated volumes at a first depth within the image icon layer, a first zone of image icons, the first zone of image icons having a first predefined subset of the plurality of retaining structures, wherein the isolated volumes of retaining structures of the first predefined subset of the plurality of retaining structures contain cured pigmented material of a first color, and a second zone of image icons, the second zone of image icons including a second predefined subset of the plurality of retaining structures, wherein the isolated volumes of retaining structures of the second predefined subset of the plurality of retaining structures contain cured pigmented material of a second color, wherein the second color contrasts with the first color.

In some embodiments, an authentication system may be configured to process one or more tokens that incorporates one or more tailored-wavelength-range coded patterns, codes represented within a steganographic image, or “overlapping” codes. As an example, such a token may include (i) one or more invisible-ink-printed patterns printed using infrared ink corresponding to different tailored wavelength ranges within the infrared light spectrum, (ii) one or more steganographic images in which invisible-ink-printed patterns are interweaved within the steganographic images, (iii) visible-ink-printed patterns and invisible-ink-printed patterns printed substantially within the visible ink portions of the visible-ink-printed patterns, or (iv) other features, where the invisible-ink-printed patterns correspond to one or more authentication codes or other data for token authentication.

A micro-optic security device with zonal color transitions includes a planar array of focusing elements, an image icon layer including a plurality of retaining structures, the plurality of retaining structures defining isolated volumes at a first depth within the image icon layer, a first zone of image icons, the first zone of image icons having a first predefined subset of the plurality of retaining structures, wherein the isolated volumes of retaining structures of the first predefined subset of the plurality of retaining structures contain cured pigmented material of a first color, and a second zone of image icons, the second zone of image icons including a second predefined subset of the plurality of retaining structures, wherein the isolated volumes of retaining structures of the second predefined subset of the plurality of retaining structures contain cured pigmented material of a second color, wherein the second color contrasts with the first color.

A micro-optic security device with zonal color transitions includes a planar array of focusing elements, an image icon layer including a plurality of retaining structures, the plurality of retaining structures defining isolated volumes at a first depth within the image icon layer, a first zone of image icons, the first zone of image icons having a first predefined subset of the plurality of retaining structures, wherein the isolated volumes of retaining structures of the first predefined subset of the plurality of retaining structures contain cured pigmented material of a first color, and a second zone of image icons, the second zone of image icons including a second predefined subset of the plurality of retaining structures, wherein the isolated volumes of retaining structures of the second predefined subset of the plurality of retaining structures contain cured pigmented material of a second color, wherein the second color contrasts with the first color.

Aspects described herein may provide detection of a feature of an authorization code image (ACI) incorporated onto a document, thereby allowing for validation of the document. According to some aspects, these and other benefits may be achieved by an instance of a variable protocol that may specify how to generate the ACI to have a particular feature as well as how to detect the particular feature of the ACI. A recipient of the document incorporating the ACI may detect the particular feature of the ACI. If the detected feature matches an expected feature, then the ACI and the document may be determined to be authentic.

Aspects described herein may provide detection of a feature of an authorization code image (ACI) incorporated onto a document, thereby allowing for validation of the document. According to some aspects, these and other benefits may be achieved by an instance of a variable protocol that may specify how to generate the ACI to have a particular feature as well as how to detect the particular feature of the ACI. A recipient of the document incorporating the ACI may detect the particular feature of the ACI. If the detected feature matches an expected feature, then the ACI and the document may be determined to be authentic.

A payment card includes hidden features (e.g., textual messages, graphics, emphasis features associated with conspicuous features of the payment card, or the like) undiscernible under only visible light, but discernable under ultraviolet light. The hidden features can be incorporated into multiple layers of a side of the payment card and can be present with different transparencies, different colors, and different persistence.