A security document may include a laserizable first layer including a grayscale image formed by laserizing; a color pattern that is in alignment with the grayscale image; and a second layer arranged between the first layer and the pattern, such that the first layer is above the second layer, and the pattern is below the second layer. The second layer may be more opaque than the first layer, such that when observing the security document from the top, the grayscale image appears to be colored by the color pattern only when the bottom of the security document is being illuminated.

A security document may include a laserizable first layer including a grayscale image formed by laserizing; a color pattern that is in alignment with the grayscale image; and a second layer arranged between the first layer and the pattern, such that the first layer is above the second layer, and the pattern is below the second layer. The second layer may be more opaque than the first layer, such that when observing the security document from the top, the grayscale image appears to be colored by the color pattern only when the bottom of the security document is being illuminated.

A security document includes a first leaf having a first polymer substrate and a first reinforcement layer attached or formed with the first leaf. An outer leaf is attached to the first leaf along a fold line and is located between the first leaf and a cover. The first reinforcement layer extends along the first leaf at least partially along the fold line and at least partially away from the fold line on both sides of the fold line. The security document also has methods of manufacturing such a security document and a plurality of such security documents.

An individual certificate medium includes an optical security patch in which a relief layer and a metal layer include a first area and a second area. The first area includes an altered region and a portion of the relief layer overlapping with the altered region as viewed in the thickness direction of a recording layer. The second area includes a non-altered region and another portion of the relief layer overlapping with the non-altered region as viewed in the thickness direction. As viewed in the thickness direction, the first area transmits light incident thereon, while the second area absorbs light incident thereon to hide a recording region. In a direction intersecting the thickness direction, the first and second areas cause light incident on the optical security patch to emerge as diffracted light.

Provided are: a light diffraction layer laminated sheet which enables easy production of a card that has a light analysis structure; and a card. A light diffraction layer laminated sheet material which forms a part of a laminated structure of a card by being laminated on top of a card base material. This light diffraction layer laminated sheet material is provided with: a transparent sheet layer; a hologram layer that has a contour smaller than the contour of the transparent sheet layer and is laminated on one surface, which is the upper surface, of the transparent sheet layer; and an HS layer that bonds the transparent sheet layer and the hologram layer with each other.

Provided are: a light diffraction layer laminated sheet which enables easy production of a card that has a light analysis structure; and a card. A light diffraction layer laminated sheet material which forms a part of a laminated structure of a card by being laminated on top of a card base material. This light diffraction layer laminated sheet material is provided with: a transparent sheet layer; a hologram layer that has a contour smaller than the contour of the transparent sheet layer and is laminated on one surface, which is the upper surface, of the transparent sheet layer; and an HS layer that bonds the transparent sheet layer and the hologram layer with each other.

The present invention provides improved methods for making a multiple layer thermoplastic security document having a window using CO.sub.2 laser cutting and engraving in combination with a vision system for precision registration of cut windows of each layer and layer to layer registration and further provides application and registration of security features between layers within the security document body including an embedded gray scale watermark.

The present invention provides improved methods for making a multiple layer thermoplastic security document having a window using CO.sub.2 laser cutting and engraving in combination with a vision system for precision registration of cut windows of each layer and layer to layer registration and further provides application and registration of security features between layers within the security document body including an embedded gray scale watermark.

A display is provided with a periodic structure that is dielectric and includes a support and a plurality of periodic elements. A plurality of periodic elements is arranged on a reference plane in a two-dimensional lattice form having a sub-wavelength period and are either convexities projected or concavities recessed in the reference plane. A metal layer is disposed on a surface of the periodic structure. The surface corresponds to a plane including a region of the reference plane surrounding the individual periodic elements and surfaces of the periodic elements. The metal layer's profile conforms to a surface profile of the periodic structure. The plurality of periodic elements have an interval therebetween in a first direction in which the plurality of periodic elements are arranged in a two-dimensional lattice form. The interval is different from an interval between the periodic elements in a second direction intersecting the first direction.

A method of forming a polymer substrate for a security sheet includes: providing first and second overlapping polymer layers each providing outwardly facing surfaces, and a colour shifting element positioned between the first and second polymer layers adapted to provide a first optical effect to a viewer, wherein the first polymer layer includes a region substantially transparent to visible light such that the colour shifting element is viewable through the first polymer layer, and; joining together the first and second polymer layers in order to generate a polymer substrate wherein, during the joining step, a surface relief is formed in the outwardly facing surface of the first layer, the surface relief being adapted to interact with light from the colour shifting element in order to modify the first optical effect to provide a second optical effect different from the first optical effect.