A forgery prevention medium includes a substrate and a specific invisible material layer directly or indirectly laminated on the substrate, having a specific invisible material reversibly and visually recognized through a predetermined process disposed thereon in a plane shape, and having a part of the specific invisible material inactivated in accordance with a visualized image pattern.

In a drawing method according to an embodiment of the present disclosure, when performing drawing on a thermal recording medium that includes, above a recording layer, a light-transmitting member having an uneven shape in a plane, an optical compensator having one surface and another surface is provided on the light-transmitting member to cause the one surface and the light-transmitting member to face each other, and the thermal recording medium is irradiated with a laser beam via the optical compensator. The one surface of the optical compensator has a shape that fits the uneven shape of the light-transmitting member, and the other surface is flat and opposed to the one surface.

Embodiments relate to producing micro-image elements on a substrate for a security document, the method comprising: producing a plurality of microstructure units comprising three-dimensionally structured formations in a clear or pale relief layer on the substrate; and applying a coloured ink fluid to the relief layer, wherein the coloured ink fluid accumulates preferentially in regions of high surface curvature on each microstructure unit to provide contrasting areas of different ink density.

The present invention relates to a method for producing water-insoluble quantum dot patterns on and/or within a substrate. The method comprises a step of depositing a deliquescent salt, quantum dots and an acid or salt thereof onto at least one surface region of a substrate such that the deliquescent salt, the quantum dots and the acid or salt thereof are at least partially contacted to form said at least one water-insoluble pattern.

Disclosed is a mechanically readable code including a first area comprising multiple first unit cells and including an information region where information was recorded and a second area including multiple second unit cells including an allochroic cell that changes in color depending on a physical quantity. The multiple first unit cells include transitional color cells having any transitional color in the process of color change of the allochroic cell.

Disclosed is a method for manufacturing a multilayer data medium (1), in which method: a multilayer data medium, including at least one transparent security layer (16), and at least one marking layer (17), sensitive to electromagnetic-marking radiation (5), are selected; the transparent security layer (16) includes at least one semi-transparent printed image including at least one thermochromic dye; at least one marking (30) is made using the electromagnetic-marking radiation, through the printed image; the semi-transparent printed image reveals, in a first state referred to as the inactivated state, at least one semi-transparent visible pattern that makes it possible, after the marking step, to view the marking (30) through the image, the pattern not being visible in a second state, referred to as the activated state. The invention also relates to a multilayer data medium (1).

Disclosed is a mechanically readable code including a first area comprising multiple first unit cells and including an information region where information was recorded and a second area including multiple second unit cells including an allochroic cell that changes in color depending on a physical quantity. The multiple first unit cells include transitional color cells having any transitional color in the process of color change of the allochroic cell.

A method of manufacturing a water-insoluble pattern on and/or within a substrate is described. Also described, is a substrate obtained by such a method, a product including such a substrate and the use of the substrate in different applications.

The present invention addresses the problem of providing a temperature detection label capable of preventing falsification using a simple structure. To solve this problem, the present invention provides a temperature detection label that is characterized by comprising a supporting member and a temperature detection part provided on the supporting member and in that: the temperature detection part has a temperature detection material that, in a heating process, starts color development at temperature T.sub.1 and starts losing color as a result of melting at temperature T.sub.2 and, in a cooling process, solidifies while remaining colorless by being cooled to temperature T.sub.1 or lower; the temperature detection material includes a leuco dye, decolorizer, and developer; and the temperature detection label also comprises a member having an appearance that changes between T.sub.1 and T.sub.2, inclusive, or a high-melting-point material having a melting point or glass transition temperature higher than T.sub.2.

Encrypted markers that are not readily detectable can be revealed by treatment with a specific reagent used as a developer to reveal a readily detectable physical property of the marker, such as a characteristic fluorescence emission after excitation with a particular excitation wavelength, or to reveal a visible color. The encrypted marker can be developed in situ, or a sample can be removed by brushing, scraping, swabbing or scratching the marked object or item and developing the encrypted marker or a sample thereof with the appropriate developer to reveal an overt marker or optical signal. The encrypted marker may include a DNA taggant.