Radiation imagery chemistry: process – composition – or product th – Holographic process – composition – or product – Composition or product or process of making the same
Patent
1997-03-24
1998-08-18
Angebranndt, Martin
Radiation imagery chemistry: process, composition, or product th
Holographic process, composition, or product
Composition or product or process of making the same
430 1, 430430, 430461, 359 3, G03H 104, G03C 526, G02B 532
Patent
active
057956812
DESCRIPTION:
BRIEF SUMMARY
The present invention pertains to a process for the stabilization of holographic support materials based on gelatin, and to light-directing wall elements for buildings.
From DE 38 40 262 A1, a transparent wall element is known which has a coating containing a holographic diffraction grating. Incident light can be deflected or reflected thereby depending on the type of the holographic diffraction grating. This wall element is useful, for example, for windows, room partitioners or facade panels and may be employed for improving the room illumination with daylight, for the reflection of heat radiation. or for display purposes.
After the exposure, holographic support materials are processed according to methods which are per se known in the field of photography, for example, from Ullmanns Enzyklopadie der technischen Chemie, 4th edition, vol. 18, item "Photographie", 1979. Holographic support materials which are in particular employed as light-directing wall elements for buildings are exposed to incident light for a large period of time. If such a holographic support material still contains residual silver halide, darkening will occur. P. Hariharan, Optical Holography, Cambridge University, Pren (1984), page 104, 105, describes a process yielding holographic support materials which are said to be light-stable. In this process which is especially adapted to the treatment of photographic plates of the type 649 F manufactured by Kodak, the support material is developed after the. exposure and, after quenching the development process, is dipped into a bleaching bath based on an oxidative cross-linking agent to reoxidize the developed silver to Ag.sup.+ and thereby to cure the gelatin film locally. The efficiency of 70% given by the authors is not sufficient for technical uses since at least 90% is required in this case. Reworking the process gave no measurable efficiency for a hologram. It is the object of the present invention to overcome this problem.
The above-mentioned problem is solved by a process for the stabilization of holographic support materials based on gelatin, characterized in that after (i) exposing, (ii) developing, and (iii) quenching said support material, there is added thereto (iv) a bleaching bath based on an oxidative cross-linking agent at a pH value of at least 3 or more, and thereafter, following (v) rinsing, (vi) fixing, (vii) additional rinsing and (viii) a final bath, (ix) said support material is dehydrated by the use, of one or more baths in series containing a solvent which is water-miscible and does not affect the cured gelatin structure.
By means of the present invention, it is possible to provide an excellently good stabilization for known holographic supports based on gelatin. After the usual exposing and developing of the holographic diffraction grating, the holographic support material based on gelatin is introduced in a stop bath. As photographic developers, developing materials may be used which are per se known in the prior art. According to the invention, a two-component developer based on ascorbic acid as component A and an alkaline sodium hydrogenphosphate solution containing a lime protection agent as component B has proven to be particularly useful. Optionally, per se known developer additives, such as buffers, anti-oxidants and antifogging agents, may be employed.
In order to quench the developing process quickly and as uniformly as possible, an acidic stop bath known in the field of photography is employed. According to the invention, an 0.5 to 2% by weight aqueous solution of acetic acid has also proven to be particularly useful. Whereas such a stop bath, in the field of photography, may usually contain agents for curing gelatin, for example, formaldehyde or an aluminum salt (curing/stop bath), no curing process is performed in this process step according to the invention since this is inserted as a separate process step prior to the fixing.
The core of the present invention is the bleaching bath based on an oxidative cross-linking agent. Said oxidative cross-linkin
REFERENCES:
patent: 2476544 (1949-07-01), Harsh et al.
patent: 3264107 (1966-08-01), Von Wartburg et al.
patent: 3660091 (1972-05-01), Shankoff et al.
patent: 4187106 (1980-02-01), Gladden
patent: 4510221 (1985-04-01), Gorin et al.
patent: 4826290 (1989-05-01), Wreede et al.
Shankoff et al., Appl. Phys. Lett., 13(7) pp. 239-241, Oct. 1968.
Pennington et al., Appl. Opt., 9(7) pp. 1643-1650, Jul. 1970.
Upatnieks et al., Appl. Opt., 8(1) pp. 85-89, Jan. 1969.
Schmackpfeffer et al., IBM J. Res. Develop., 14(5) pp. 533-538, Sep. 1970.
Gutjahr Jorg
Muller Helmut
LandOfFree
Stabilization of holograms formed in gelatin does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Stabilization of holograms formed in gelatin, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stabilization of holograms formed in gelatin will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1113320