Patent EP-1492092-B1 (EP)
Inventor: AKIBA MASAHARU
IPC: G11B7/246
Filed: 2004-06-25
Granted: 2011-04-13
Abstract: A two-photon absorbing optical recording material comprises: a two-photon absorbing compound and a recording component in which a recorded area and an unrecorded area are formed by utilizing a two-photon absorption of the two-photon absorbing compound, and a reflectance or transmittance differs between the recorded area and the unrecorded area. Independent claims are included for the following: (a) a two-photon absorbing optical recording medium comprising the two-photon absorbing optical recording material; (b) a two-photon absorbing optical recording and reproduction method, involving irradiating the recording material with laser light at a wavelength being longer than the linear absorption band of the two-photon absorbing compound and having no linear absorption to thereby induce a two-photon absorption, and performing a recording by utilizing the two-photon absorption; (c) a two-photon absorbing optical recording and reproduction method for recording and reproducing on and from a two-photon absorbing optical recording material that contains a two-photon absorbing compound and a recording component, involving: performing a recording by utilizing a two-photon absorption of the two-photon absorbing compound; and then irradiating the material with light to detect a difference in the reflectance or transmittance between the recorded area and the unrecorded area of the material to perform a reproduction; (d) a photosensitive polymer composition comprising a polymer compound (a), a two-photon absorbing compound (b), an acid generator (c), and a compound (d) capable of exhibiting or changing its color by an acid, and which undergoes color formation or color change through a non-resonant two-photon absorption; (e) coloring the photosensitive polymer composition, involving irradiating the photosensitive polymer composition with light that has a longer wavelength than the longest absorption wavelength of the composition and is not absorbed by the composition, to color the composition; (f) an optical recording method that uses or contains the photosensitive polymer composition; (g) a photon-mode recording method of recording on a photon-mode recording material comprising a sensitizing dye and a recording component. The recording component includes a dye precursor capable of becoming a color-forming material having an absorption shifted to a longer wavelength than in the original state. The recording component has an absorption in a wavelength range differing from that of the sensitizing dye; and the ability to record the refractivity difference or the absorbance difference caused by the electron transfer or the energy transfer from the sensitizing dye or the excited-state color-forming material. The method involves forming the color-forming material as a latent image through irradiation with light; and self-sensitizing and self-amplifying the latent image to perform a recording as the refractivity difference or the absorbance difference. The two steps are performed with a dry treating; (h) an optical recording and reproducing method using the photon-mode recording material recorded according to the photon-mode recording method, involving irradiating the recorded material with light; and detecting the reflectance difference based on the refractivity difference or the absorbance difference to perform a reproduction; (i) a three-dimensional optical recording method involving using the photon-mode recording method.