Production of improved hologram

Abstract

Abstract PURPOSE:To make a hologram water-resistant and to improve resolving power considerably by providing thin films consisting of 2 layers on a hologram surface using a recording medium of dichromatic acid gelatin and forming the same to have optical thicknesses of odd times 1/4 the wavelengths respectively. CONSTITUTION:A hologram 3 is formed on a recording medium consisting of a substrate 1 and a dichromatic acid gelatin medium 2, and the 1st protecting film 5 (upper layer) and the 2nd protecting film 4 (lower layer) are provided on the surface thereof. If the refractive indices of the layers 5, 4 are defined as n1, n2 and geometrical film thicknesses as d1, d2, respective optical film thicknesses are n1d2, n1d2. In reproducing the hologram 3 by an He-Ne laser, the optical film thicknesses of the layers 5, 4 are set at odd times 1/4 the wavelength lambda0 used. Namely, n1d1=n2d2=lambda0/4m (m is an odd number). Polyparaxylene (n1=1.64) is used for the layer 5 and ZrO2 (n2=2.03) for the layer 4, and these are vacuum vapor-deposited to prescribed film thicknesses. Thus the hologram which is resistant to water and has good resolving power is obtained.

Inventors

• 👤 Rokuro Watabe
• 👤 渡部　六郎

Bibliographic Details