When I first became involved in the design of the 3M Laser Imager, I had NO realization of the work that had to be done in this totally new area. While the Laser Imager was being designed, the film for the system also had be produced. The first decision could be made only when we knew what kind of a light source would be used for the Laser Imager. We could have used Gas Laser Diodes, or Solid State Laser Diodes. We chose Solid State Laser Diodes because of their longevity. The diode would almost last the lifetime of the Imager and maybe even longer. The Gas Laser diode was not as stable and had to have stringent regulation to hold it with in a narrow band of the light spectrum. It also did not have the expected life that the solid state Laser Diode had. With that in mind the Laser Film could now be "invented".
When the 3M Laser Imager was introduced in 1984, it used a totally new style film that would peak in a region of the light spectrum that was used by Solid State Laser Diodes. It was sensitive in the Ultra-Violet region of the spectrum.
This was a Worlds 1st again for 3M. It took the whole industry totally off guard. It would take the rest of the market almost 4 years to catch up to 3M in this new area where no one had ever done anything. The invention of the film was necessary in order to bring the Laser Imager into the market place. Several emulsion chemists were involved in this process, because it involved a whole new chemical technology to produce the film. In this case, emulsion was placed on only one side of the film, because the laser beam would only hit one side. To place the emulsion on both sides would not have improved the system in any way, and in fact would have caused the "halation" problem experienced in the standard film systems. The film would require a special coating on the "back" side of the film just to keep the Laser beam from bouncing back through the film. The Laser beam was strong enough to completely penetrate the film, so the special coating was required. This film was developed or processed in the same fashion as a standard film and could be processed at the same speeds as other systems. It was not extremely sensitive to room light, which made it desirable for handling in areas where standard films would have become totally blackened because of film fogging.
Another area that had to be investigated was putting a special "transport coating" on the film so that its inherent smoothness would not create "sticktion" or friction. This problem presented itself as static which caused one film to stick to another or to the machine transport surface. This was solved by one of the PHD chemists who coated the film surface with PMMA (poly methyl-methacrylate). I worked just like it was supposed to. No friction or static!
3M moved even further by producing a NEW style film for the 3M Laser Imager that would not need liquid processing. This film used a new "Dry Silver" technology that was developed using Heat. It takes just 10 seconds to process the film. Now we were really speeding the system up! This Laser/Film system is now being used in Hospitals around the World.
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Last updated on 15 January 2006