Dai Nippon Printing Co., Ltd.

Minoru Azakami

Koji Eto

Kenji Ueda

Hiroyuki Ohtaki

Yoshihito Maeno

Nobuko Oikawa

Sakurako Hatori

Masachika Watanabe

Masanori Umeya

Kazutoshi Awano

Shinya Sato

Tsuyoshi Yamauchi

Keisuke Miura

Tetsuya Toshine

Toru Nishioka

Takaki Miyachi

Dai Tsukada

Eriko Hamade

Hirotada Ookawa

Atsushi Umezawa

Akihiro Mizumura

An object of the present invention is to provide a thin volume hologram sheet to be embedded sufficiently resistant to a mechanical stress such as a stress including a tensile stress, a shear stress and a compression stress at the time of processing even under a heating condition, a forgery prevention paper and a card using the same. The object is achieved by providing a volume hologram sheet to be embedded comprising a volume hologram layer, and a substrate disposed only on one side surface of the volume hologram layer using an adhesion means, wherein a peeling strength of the volume hologram layer and the substrate is 25 gf/25 mm or more.

Volume hologram sheet to be embedded, forgery prevention paper, and card

A main object of the present invention is to provide a method of producing a volume hologram laminate which can regenerate a hologram image in an arbitrary wavelength by a simple process. To attain the object, the present invention provides a method of producing a volume hologram laminate using a volume hologram forming substrate which comprises: a substrate, a volume hologram layer formed on the substrate and containing a photopolymerizable material, a resin layer, formed on the substrate so as to contact to the volume hologram layer, containing a resin and a polymerizable compound, characterized in that the producing method comprises processes of: a hologram recording process to record a volume hologram to the volume hologram layer, a substance transit process of transiting the polymerizable compound to the volume hologram layer, and an after-treatment process of polymerizing the polymerizable compound.

Method of producing volume hologram laminate

The present invention is to provide: a photosensitive composition for volume hologram recording and a photosensitive substrate for volume hologram recording, which provide increased sensitivity during hologram recording and a high refractive index modulation amount, and which do not inhibit the decolorization of the sensitizing dye; and a volume hologram recorded medium which provides high-luminance hologram images with increased productivity. Disclosed is a photosensitive composition for volume hologram recording, comprising: a photopolymerizable monomer, a photopolymerization initiator, a sensitizing dye for sensitizing the photopolymerization initiator, a binder resin, and a thiol group-containing compound, wherein the photopolymerizable monomer contains a photoradically polymerizable monomer and a photocationically polymerizable monomer; wherein the thiol group-containing compound is a chain transfer agent for the photoradically polymerizable monomer and is a polyfunctional secondary thiol compound having two or more secondary thiol groups per molecule; and wherein the content of the thiol group-containing compound is 1.5 to 30 parts by mass with respect to 100 parts by mass of the photoradically polymerizable monomer.

Photosensitive composition for volume hologram recording, photosensitive substrate for volume hologram recording, and volume hologram recorded medium

The present invention provides a volume hologram transfer foil which has good foil cutting characteristics and is used to manufacture a volume hologram laminate by transferring a volume hologram layer to an adherend by thermocompression. The volume hologram transfer foil includes a base material, a protective layer, a volume hologram layer, and a heat seal layer, wherein the protective layer contains a hard coat component, a rupture elongation control component, and a foil cutting characteristic control component which has a thermal expansion coefficient different from those of the hard coat component and rupture elongation control component and is incompatible with the two components.

Volume hologram transfer foil

A major object of the present invention is to provide a volume hologram transfer foil that gives a volume hologram laminate higher in antiforgery function. The present invention achieves the object by providing a volume hologram transfer foil comprising: a substrate, a volume hologram layer carrying a recorded volume hologram that is formed on the substrate, and an image forming layer carrying a formed image and a heat seal layer containing a thermoplastic resin that are formed on the volume hologram layer, and comprising no reflective layer having a function to reflect light.

Volume hologram transfer foil, volume hologram laminate, and production method thereof

This invention provides a volume hologram photosensitive composition, which can realize a hologram having an excellent brightness and, at the same time, having excellent heat resistance and mechanical strength, and a photosensitive medium for volume hologram recording using the volume hologram photosensitive composition. The volume hologram photosensitive composition comprises at least a photopolymerizable monomer, a photopolymerization initiator, a sensitizing dye for sensitizing the initiator, and a binder resin. The binder resin comprises a heat curing resin, and optionally a thermoplastic resin, and the thermoplastic resin is contained in an amount of 0 to 25% by weight based on the total solid content of the photosensitive composition.

Volume hologram photosensitive composition

A method of producing a volume hologram laminate which can regenerate a hologram image in an arbitrary wavelength by a simple process. The method uses a volume hologram forming substrate which includes: a substrate, a volume hologram layer formed on the substrate and containing a photopolymerizable material, a resin layer, formed on the substrate so as to contact to the volume hologram layer, containing a resin and a polymerizable compound. The producing method includes processes of: a hologram recording process to record a volume hologram to the volume hologram layer, a substance transit process of transiting the polymerizable compound to the volume hologram layer, and an after-treatment process of polymerizing the polymerizable compound.

The present invention provides an optical diffusion device, which can exhibit discontinuously different optical properties only in desired regions without creating any difference in grades and/or breaks, facilitate control of the optical diffusion properties, and prevent the occurrence of the stray light, as well as provides a projection screen and a design member, both using the optical diffusion device. An exemplary optical diffusion device according to this invention includes a base, and a cholesteric liquid crystal polymer layer provided on the base and composed of a plurality of diffusion regions arranged on a plane. A diffusion angle of one of the diffusion regions (e.g., first diffusion regions) of the cholesteric liquid crystal polymer layer is different from a diffusion angle of another of the diffusion regions (e.g., second diffusion regions).

Optical diffusion device, projection screen, design member and security medium

An object of the present invention is to provide an authenticity indicator that cannot be easily forged, that is clearly distinguishable, and that can be elaborately designed. An authenticity indicatoris in the form of a sheet and can be checked for its authenticity by observing the light reflected from it. The authenticity indicator comprises a first reflective layercomprising a reflective areathat reflects specified light, and a second reflective layerthat reflects specified light. The reflective area of the first reflective layer has a cholesteric liquid crystalline structure. The second reflective layer comprises a volume hologram.

Indicator for indicating authenticity

A counterfeiting prevention labelhas a label baseincluding a base sheet, and a volume hologramincluding a volume hologram layerand formed on the base sheet. The volume hologramis extended between the upper sideand the lower sideof the label base. The opposite end surfaces of the volume hologramare flush with the end surfaces of the label base, respectively. The volume hologrammay be placed in a depressionformed in the front surface of the label base. The volume hologramand the label baseare blanked out after transferring the volume hologramfrom a transfer sheetto the label base

Counterfeiting prevention label and method of manufacturing the same

The invention provides (1) a volume hologram transfer foil comprising a substrate and protective layer, a volume hologram layer and a heat seal layer stacked on the substrate in this order, wherein a multilayer structure comprising the protective layer, the volume hologram layer and the heat seal layer in this order is releasable from the substrate, and (2) a volume hologram transfer foil wherein the above protective layer is used as a heat seal layer. The heat seal layer comprises a polyester resin having a glass transition temperature of &#x2212;10&#xb0; C. to &#x2212;30&#xb0; C. With the invention, thermo-compression adhesion of the volume hologram layer to any application member, especially a polyester resin card is improved, so that the invention provides a volume hologram transfer foil useful for prevention of illegal copying, and a volume hologram multilayer structure formed using such a transfer foil.

Volume hologram transfer foil, and volume hologram multilayer structure

A magnetic card of the invention comprises a card substrateon which a magnetic layer, a thin-film layerformed of a metal or a metal compound for concealing the magnetic layer, a printed layerand a volume hologram layerare successively provided, wherein magnetic information is recorded on or read from a volume hologram layer side. The volume hologram layeris composed essentially of a photosensitive material comprising a cationic polymerizable compound, a radical polymerizable compound, a photo-radical polymerization initiator system that is sensitive to light of a specific wavelength to polymerize the radical polymerizable compound, and a photo-cationic polymerization initiator system that is less sensitive to the light of a specific wavelength but sensitive to light of another wavelength to polymerize the cationic polymerizable compound. The magnetic card is improved in terms of wear resistance to sliding contact with a magnetic head, and ensures precise writing or reading of magnetic recording data, with improved ability to prevent forgery.

Growing community of inventors

Tokyo-to, Japan

Minoru Azakami