HOLOGRAM RECORDING MEDIUM
The present invention provides a hologram recording medium wherein, in holographic memory recording using a blue laser as well as a green laser, a fall in light transmittance is very small even after recording. A hologram recording medium comprising at least a hologram recording material layer, wherein the hologram recording material layer ( 21 ) comprises at least fine particles of a metal compound, and a photopolymerizable compound; and the recording sensitivity of said recording medium ( 11 ) to a laser light having a wavelength of 405±5 nm is 0.05 cm/mJ or more and 1.20 cm/mJ or less.
1 . A hologram recording medium comprising at least a hologram recording material layer,
wherein the hologram recording material layer comprises at least fine particles of a metal compound, and a photopolymerizable compound; and
a recording sensitivity of the recording medium to a laser light having a wavelength of 405±5 nm is 0.05 cm/mJ or more and 1.20 cm/mJ or less.
2 . The hologram recording medium according to claim 1 ,
wherein a particle diameter of the fine particles of the metal compound is 0.5 nm or more and 50 nm or less, the particle diameter being represented by a mode value of a particle size distribution of said fine particles as determined by a dynamic light scattering method; and
the fine particles of the metal compound form a matrix structure in the hologram recording material layer before and after information recording.
3 . The hologram recording medium according to claim 1 , wherein the hologram recording material layer has a thickness of at least 100 μm.
4 . The hologram recording medium according to claim 1 , wherein the metal compound contains at least Si as a metal, and has an Si—O bond.
5 . The hologram recording medium according to claim 4 , wherein the metal compound further contains, as a metal, a metal other than Si selected from the group consisting of Ti, Zr, Nb, Ta, Ge and Sn, and has a bond of said metal-O.
6 . The hologram recording medium according to claim 5 , wherein a complexing ligand is coordinated to at least one portion of the metal other than Si contained in the metal compound.
7 . The hologram recording medium according to claim 6 , wherein the completing ligand is selected from the group consisting of β-dicarbonyl compounds, polyhydroxylated ligands, and α- or β-hydroxy acids.
8 . The hologram recording medium according to claim 1 , which has a light transmittance of 70% or more at a wavelength of 405±5 nm, or has a light reflectance of 49% or more at a wavelength of 405±5 nm, before information is recorded into the recording medium.