A display medium including a first layer, a second layer, and a third layer, wherein: a part or an entirety of the first layer, a part or an entirety of the second layer, and a part or an entirety of the third layer are stacked in a thickness direction in this order; the first layer is a layer that is capable of reflecting circularly polarized light having a rotation direction D1 and allowing to pass therethrough circularly polarized light having a rotation direction D2, which is a direction opposite to the rotation direction D1; the second layer is a phase difference layer; and the third layer is a layer that is capable of reflecting circularly polarized light whose rotation direction is the rotation direction D1 and allowing to pass therethrough circularly polarized light whose rotation direction is the rotation direction D2.

A display medium including a first layer, a second layer, and a third layer, wherein: a part or an entirety of the first layer, a part or an entirety of the second layer, and a part or an entirety of the third layer are stacked in a thickness direction in this order; the first layer is a layer that is capable of reflecting circularly polarized light having a rotation direction D1 and allowing to pass therethrough circularly polarized light having a rotation direction D2, which is a direction opposite to the rotation direction D1; the second layer is a phase difference layer; and the third layer is a layer that is capable of reflecting circularly polarized light whose rotation direction is the rotation direction D1 and allowing to pass therethrough circularly polarized light whose rotation direction is the rotation direction D2.

Provided is an information display medium that can enhance a forgery prevention effect. An information display medium (100) includes a light reflection layer (20) made of a metal or a metallic oxide and partially or fully placed on one surface of a substrate, and the light reflection layer (20) includes a first region (30) where first information is displayed by either of or a combination of an outline shape and a shape of an uneven region, and a second information display region (21a) where identification information formed by partial material removal of the light reflection layer (20), the second information display region being set to partially or fully overlap with the light reflection layer (20) where the first information is displayed in the first region (30).

A security device is provided, comprising: a colour shifting element that exhibits different wavelengths of light at different viewing angles, and; an at least partially transparent light control layer covering at least a part of the colour shifting element and comprising a surface relief adapted to modify the angle of light from the colour shifting element, wherein; a first region of the light control layer comprises a first optical characteristic, whereby light at a first viewing angle from the first region of the light control layer is perceived to have a resultant optical effect that is the resultant of the wavelength of light exhibited at that viewing angle due to the combination of the colour shifting element and the surface relief of the light control layer, and the first optical characteristic, and; a second region of the light control layer either: (i) is substantially colourless such that light at the first viewing angle from the second region is perceived to have a resultant optical effect exhibited at that viewing angle due to the combination of the colour shifting element and the surface relief of the light control layer, or; (ii) comprises a second optical characteristic different from the first optical characteristic, whereby light at the first viewing angle from the second region of the light control layer is perceived to have a resultant optical effect that is the resultant of the wavelength of light exhibited at that viewing angle due to the combination of the colour shifting element and the surface relief of the light control layer, and the second optical characteristic. Methods of manufacture thereof are also disclosed.

A security device is provided, comprising: a colour shifting element that exhibits different wavelengths of light at different viewing angles, and; an at least partially transparent light control layer covering at least a part of the colour shifting element and comprising a surface relief adapted to modify the angle of light from the colour shifting element, wherein; a first region of the light control layer comprises a first optical characteristic, whereby light at a first viewing angle from the first region of the light control layer is perceived to have a resultant optical effect that is the resultant of the wavelength of light exhibited at that viewing angle due to the combination of the colour shifting element and the surface relief of the light control layer, and the first optical characteristic, and; a second region of the light control layer either: (i) is substantially colourless such that light at the first viewing angle from the second region is perceived to have a resultant optical effect exhibited at that viewing angle due to the combination of the colour shifting element and the surface relief of the light control layer, or; (ii) comprises a second optical characteristic different from the first optical characteristic, whereby light at the first viewing angle from the second region of the light control layer is perceived to have a resultant optical effect that is the resultant of the wavelength of light exhibited at that viewing angle due to the combination of the colour shifting element and the surface relief of the light control layer, and the second optical characteristic. Methods of manufacture thereof are also disclosed.

An identification medium including a light reflection layer and a patterned phase difference layer, wherein the light reflection layer is a layer that reflects incident light as circularly polarized light or linearly polarized light, and the patterned phase difference layer is a layer that includes an area having a phase difference, and is a layer provided in the identification medium so that the area having a phase difference occupies a partial area of a display surface of the identification medium. Also provided are an article including the identification medium, and a method for using the identification medium wherein, in observation of the reflected light, a linear polarization component or a circular polarization component of the reflected light is selectively observed, or linearly polarized light, circularly polarized light, or elliptically polarized light is made incident as the incident light.

An identification medium including a light reflection layer and a patterned phase difference layer, wherein the light reflection layer is a layer that reflects incident light as circularly polarized light or linearly polarized light, and the patterned phase difference layer is a layer that includes an area having a phase difference, and is a layer provided in the identification medium so that the area having a phase difference occupies a partial area of a display surface of the identification medium. Also provided are an article including the identification medium, and a method for using the identification medium wherein, in observation of the reflected light, a linear polarization component or a circular polarization component of the reflected light is selectively observed, or linearly polarized light, circularly polarized light, or elliptically polarized light is made incident as the incident light.

A method for producing a decorative element and uses of a decorative element. A polarizing layer functioning as an analyzer is applied to a transparent optical carrier material and a transparent optical functional layer is applied as an image-forming layer including an optically anisotropic material. By spatially structuring the functional layer, a targeted location-dependent dependency of material properties of the optically anisotropic material is created for producing the image-forming layer. One or several decorative elements produced can each be introduced into a light field of a lighting device in a desired shape, size and quantity and having settable image motifs (image structures) and being disposed at different spatial distances and being freely disposable. The decorative element produced is intended to be used as an architectural element for creating light-optical effects in the exterior area of buildings, as a design element for interior design or for object design.

A method for producing a decorative element and uses of a decorative element. A polarizing layer functioning as an analyzer is applied to a transparent optical carrier material and a transparent optical functional layer is applied as an image-forming layer including an optically anisotropic material. By spatially structuring the functional layer, a targeted location-dependent dependency of material properties of the optically anisotropic material is created for producing the image-forming layer. One or several decorative elements produced can each be introduced into a light field of a lighting device in a desired shape, size and quantity and having settable image motifs (image structures) and being disposed at different spatial distances and being freely disposable. The decorative element produced is intended to be used as an architectural element for creating light-optical effects in the exterior area of buildings, as a design element for interior design or for object design.

The present invention relates to a structure for a physical unclonable function using spontaneous chiral symmetry breaking and a method of preparing the same, in which a chiral random pattern, which is unclonable and is observable with an optical microscope and a mobile phone camera, is formed using chiral photonic crystals in which chiral symmetry breaking occurs and is applied to a physical unclonable function (PUF), thereby attaining high encoding capacity, high recognition rate, and security while achieving high performance in reproducibility, uniqueness, unpredictability, and reconfigurability, and forming a desired pattern through a conventional photolithography method.