Environmental monitors for monitoring a predetermined environmental exposure, for example, an historical heat exposure such as a cumulative ambient heat exposure and/or a peak ambient heat exposure may include an environmental indicator material and a security material. The environmental monitor may be configured to attach to a host product for monitoring the predetermined environmental exposure of the host product, and additionally serve as an anti-counterfeiting indicator.

A lens pigment suitable for manufacturing value documents by printing technology, includes a carrier substrate which forms a lens base and which is supplied on its front side with a first plastic having at least one elevation that produces a microlens and with a second plastic leveling the first plastic.

Disclosed are a magnetic particle and a security ink containing the same. The magnetic particle includes a magnetic core, and a metal coating layer formed outside the magnetic core. The magnetic particle has a surface roughness (Ra) of 0.15 μm or less. The magnetic particle according to the present invention is suitable for application to a security ink because an abnormal increase in particle size does not occur after the metal coating layer is formed.

Disclosed are a magnetic particle and a security ink containing the same. The magnetic particle includes a magnetic core, and a metal coating layer formed outside the magnetic core. The magnetic particle has a surface roughness (Ra) of 0.15 μm or less. The magnetic particle according to the present invention is suitable for application to a security ink because an abnormal increase in particle size does not occur after the metal coating layer is formed.

The present disclosure is a thermal transfer sheet including a substrate and a transfer layer, the transfer layer containing a luster pigment, wherein, when an image of the sheet is taken from a side on which the transfer layer is present, the image is analyzed, dark and light portions of the analyzed image are inverted, automatic thresholding is performed in order to determine a threshold value of a brightness distribution, binary representation is subsequently performed, and the number and the total area of the black portions and the total area of the white portions are calculated, the ratio of the total area of the black portions to the total area of the white portions is 0.03 to 0.5, and the black portions have an average area of 100 to 300 μm.sup.2.

A security system for an article of manufacture includes one or more first planchettes and one or more second planchettes included in the article. The first planchettes luminesce under a first frequency of light and the second planchettes luminesce under a second frequency of light with at least one of three characteristics. First, the first frequency is different from the second frequency, the first planchettes do not luminesce under the second frequency of light, and the second planchettes do not luminesce under the first frequency of light. Second, the first planchettes luminesce at a first color under the first frequency of light and the second planchettes luminesce at a second color different from the first color under the second frequency of light. Third, the first planchettes reflect a first pattern under the first frequency of light and the second planchettes reflect a second pattern under the second frequency of light.

An optical device includes an array of lenses and a plurality of segments disposed under the array of lenses. The plurality of segments corresponds to a plurality of images. Upon tilting the device at different viewing angle, the array of lenses presents images sequentially. In some examples, individual ones of the segments can comprise specular reflecting, transparent, diffusely reflecting, and/or diffusely transmissive features. In some examples, individual ones of the segments can comprise transparent and non-transparent regions. The images can produce one or more optical effects.

An optical device includes an array of lenses and a plurality of segments disposed under the array of lenses. The plurality of segments corresponds to a plurality of images. Upon tilting the device at different viewing angle, the array of lenses presents images sequentially. In some examples, individual ones of the segments can comprise specular reflecting, transparent, diffusely reflecting, and/or diffusely transmissive features. In some examples, individual ones of the segments can comprise transparent and non-transparent regions. The images can produce one or more optical effects.

A security article may include a substrate. The security article may include a layer of security ink. The layer of security ink may include a set of color-shifting interference particles. The security article may include a layer of magnetic color-shifting ink. The layer of magnetic color-shifting ink may include a set of magnetically aligned magnetic particles. A color-shifting property of the layer of security ink and a color-shifting property of the layer of magnetic color-shifting ink may have a threshold level of similarity to create a color matching effect.

A security article may include a substrate. The security article may include a layer of security ink. The layer of security ink may include a set of color-shifting interference particles. The security article may include a layer of magnetic color-shifting ink. The layer of magnetic color-shifting ink may include a set of magnetically aligned magnetic particles. A color-shifting property of the layer of security ink and a color-shifting property of the layer of magnetic color-shifting ink may have a threshold level of similarity to create a color matching effect.