| 摘要 |
PURPOSE:To provide the improvement in moisture resistance, the decrease in deteriora tion with age and light scattering and the reduction in cost by irradiating interference light to a film formed by dissolving a specific low saponification type PVA resin contg. dichromate in an org. solvent compatible with water and drying thereby record ing the interference fringes in the form of a spacial refractive index distribution. CONSTITUTION:A blank hologram material is obtd. by dissolving the low saponification PVA contg. the dichromate and having <=70% degree of saponification in the highly polar org. solvent compatible with water, pouring a prescribed amt. of such photosensitive liquid onto an optically transparent glass substrate 1 and drying the same in a vacuum within the range where a thermal dark reaction arises hardly. The hologram consisting of the lattice groups of the parallel plane perpendicular to the film plane, i.e., the distribution of high and low refractive indices is recorded on the resin film 2 when laser beams 7a and 7b are irradiated thereto from an argon laser device 3 for several seconds or above. The easy and inexpensive formation of a large quantity of phase holograms having a large area is thus made possible. Since the hologram film is optically uniform in quality and scatters less light, there is no deterioration of S/N in the reconstruction stage of the hologram; in addition, the moisture resistance is improved and the deterioration with age is decreased. |
