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Automated Spin Development of Phase Holograms in Dichromated Gelatin

IP.com Disclosure Number: IPCOM000102329D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Hodgson, RT: AUTHOR [+3]

Abstract

Development of high efficiency holograms in dichromated gelatin (DCG) has historically been an expensive, delicate, and time consuming process. The industry-accepted method for DCG development has been to dip the substrates in sequential baths containing various concentrations of isopropanol and water. The water can be withdrawn from the DCG rapidly enough to produce high efficiency holograms. However, there are problems with this process: 1. The substrate is submersed in a first-in, last-out manner so that each area of the DCG is exposed to the isopropanol for a different amount of time, which results in uneven development. 2. The substrate is submersed by hand. Extra steps must be introduced into the process to smooth out the variation caused by humans. 3.

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This is the abbreviated version, containing approximately 52% of the total text.

Automated Spin Development of Phase Holograms in Dichromated Gelatin

       Development of high efficiency holograms in dichromated
gelatin (DCG) has historically been an expensive, delicate, and time
consuming process.  The industry-accepted method for DCG development
has been to dip the substrates in sequential baths containing various
concentrations of isopropanol and water.  The water can be withdrawn
from the DCG rapidly enough to produce high efficiency holograms.
However, there are problems with this process:
   1. The substrate is submersed in a first-in, last-out manner so
that each area of the DCG is exposed to the isopropanol for a
different amount of time, which results in uneven development.
   2. The substrate is submersed by hand.  Extra steps must be
introduced into the process to smooth out the variation caused by
humans.
   3. Large quantities of electronic grade isopropanol and deionized
water are required to fill the developing tanks.
   4. The entire development process takes 14 minutes, including a 10
minute water soak.
   5. The isopropanol/water temperature is difficult to maintain
because of the high level of evaporation.
   6. The concentration of isopropanol is difficult to maintain
because of the evaporation and because of "drag through"
contamination/dilution from one bath to the next.
   7. This drag through can become very expensive if one of the baths
becomes contaminated with a foreign substance. In that event, every
tank must be dumped, cleaned, refilled, and brought back up to proper
temperature, thus wasting much time and man...