JP-2026075770-A - Authenticity printed matter

Abstract

【assignment】 The present invention provides a genuineness-determinating printed material in which the color-changing properties of a luminous material and the color change of visible emission caused by excitation light do not interfere with each other, and through the synergistic effect of both, machine readability is possible even with a small amount of light-emitting material, without hindering the visibility of the luminous material. [Solution] The present invention relates to a truth-discriminating printed material that performs truth-discrimination based on emission of excitation light in a predetermined wavelength range when a discrimination region formed by printing is irradiated with excitation light, wherein the discrimination region consists of a first luminous luminescent layer formed of a first luminous luminescent ink containing a luminescent element that emits light in a predetermined wavelength range different from the excitation light, and a luminous material whose reflectance peak wavelength is a first maximum wavelength, and the first maximum wavelength is different from at least one of the maximum wavelengths of a second maximum wavelength, which is the excitation peak wavelength of the excitation light, and a third maximum wavelength, which is the peak wavelength of emission from the luminescent element. [Selection Diagram] Figure 1

Inventors

• 藤澤 直子

Assignees

• 独立行政法人 国立印刷局

Dates

Publication Date

20260511

Application Date

20241023

Claims (3)

1. A printable material that performs authenticity determination based on emission of excitation light in a predetermined wavelength range when a discrimination area formed by printing is irradiated with excitation light, The aforementioned discrimination region is i) A first luminescent layer formed by a first luminescent ink containing a light-emitting element that emits light in a predetermined wavelength range different from the excitation light, and a luminescent material whose peak reflectance wavelength is a first maximum wavelength, or ii) A second luminous emitting layer is formed by laminating a first luminescent ink containing a luminescent element that emits light in a predetermined wavelength range different from the excitation light, and a first luminous ink containing a luminous material whose peak reflectance wavelength is a first maximum wavelength. The first maximum wavelength in i) or ii) above is A truth-discrimination printed material characterized in that the second maximum wavelength, which is the excitation peak wavelength of the excitation light, and the third maximum wavelength, which is the peak wavelength of the emission of the light emitter, are different from at least one of the maximum wavelengths.
2. A luminescent ink comprising a mixture of a light-emitting element that emits light in a predetermined wavelength range different from the excitation light in a predetermined wavelength range, a luminescent material, and a binder resin, wherein A luminous luminescent ink characterized in that the first maximum wavelength, which is the peak wavelength of the reflectance of the luminous material, is different from at least one of the maximum wavelengths of the excitation peak wavelength of the excitation light and the third maximum wavelength, which is the peak wavelength of the emission of light from the light emitter.
3. The luminous material is a transparent pearl pigment with a reflectance of 45% or less at the wavelength of the excitation light and the wavelength of emission of the light-emitting element, as described in claim 2.

Description

This invention relates to a printable material used for authenticity detection. High-level authentication technology is required for valuable printed materials such as banknotes, passports, revenue stamps, postage stamps, securities, identification cards, various tickets, and security labels. Examples of authenticity determination technologies include techniques that form a luminous image using an ink containing a luminous material and visually confirm the change in the color of the luminous image according to the observation angle, or methods that form a luminescent image using a fluorescent ink containing a light-emitting element that emits fluorescence when irradiated with ultraviolet, visible, or infrared light, and read the fluorescence of the luminescent image with a detector. Among these, the method of determining authenticity by adding a light-emitting element that emits light in the near-infrared region invisible to the human eye and detecting this emission with a reading device is particularly effective and offers high confidentiality. As an example, a counterfeit prevention ink is disclosed that contains a fluorescent pigment whose fluorescent emission color changes upon irradiation with ultraviolet or infrared light, and a luminescent material, along with a printed material using this counterfeit prevention ink (see, for example, Patent Document 1). Japanese Patent Publication No. 2002-285061 Example of a printable document for authenticity verification (A1)An example diagram showing the spectral reflectance of pearl pigments.Example of a printable document for authenticity verification (A2 size) Next, embodiments for carrying out the present invention will be described, but the present invention is not limited thereto, and other embodiments are also included as long as they fall within the scope of the technical idea described in the claims. (First embodiment) Figure 1 shows a genuine-false-discriminating printed material (A1) in the first embodiment. Figure 1(a) is a plan view of the genuine-false-discriminating printed material (A1). As shown in Figure 1(a), the genuine-false-discriminating printed material (A1) has a discrimination region (2) formed by a first luminous-emitting layer (6) on at least a part of the substrate (1). The margins of the substrate (1) other than the discrimination region (2) may have unique information (3) such as numbers, characters, or photographs, and a part of the unique information (3) may be laminated on the discrimination region (2) if it does not affect the luminescence of the discrimination region (2). (discrimination area) The shape of the discrimination area (2) is not limited as long as it can be used for authenticity determination. It may be a figure, mark, etc. formed by solid printing or halftone printing, or it may be a letter, number, etc. It may be a line (curved line, straight line), a colored pattern, etc., or code information including a barcode or two-dimensional code. In addition, an overcoat may be applied to the entire surface of the substrate (1). Next, Figure 1(b) shows a cross-sectional view of the authenticity-determining printed material (A1) at the A-A' point in the first embodiment. The first luminous emitting layer (6) is formed from a luminescent material that emits light in a predetermined wavelength range different from the excitation light, and a first luminous emitting ink containing a luminescent material that does not hinder the effects of the excitation light and emission. (Luminous object) The light-emitting material that constitutes the first luminous light-emitting layer (6) is not particularly limited as long as it is a light-emitting material that emits light in a predetermined wavelength range different from the excitation light when excited by excitation light in a predetermined wavelength range, and known light-emitting materials can be used. The excitation light may be in the ultraviolet region, the visible light region, or the infrared region. Furthermore, the light-emitting material used in the present invention may be one type or two or more types may be mixed and used, and upconversion materials that are light-emitting materials that absorb near-infrared light and emit visible light are also included. Next, an example of a light-emitting material is given. Examples of light-emitting materials include organic fluorescent materials such as arylamine derivatives, anthracene derivatives (phenylanthracene derivatives, etc.), pentacene derivatives, azole derivatives (oxadiazole derivatives, oxazole derivatives, triazole derivatives, benzoxazole derivatives, benzoazotriazole derivatives, etc.), thiophene derivatives (oligothiophene derivatives, etc.), carbazole derivatives, diene derivatives (cyclopentadiene derivatives, tetraphenylbutadiene derivatives, etc.), distyrylbenzene derivatives, distyrylpyrazine derivatives, distylylarylene derivatives, stilbene derivatives, silole derivatives, and spiro compounds. Examples o