Technology: Melting moment makes a microfilm reusable - pet melting point
Elislav GEAKE's new microfilm is erasable, does not require photographic processing, and can store digital data, pictures and text should be available in about 18 months.
Similar to the LCD in the laptop screen and digital watch form the basis of the movie.
Everything that needs to be written on it is a tiny solid
Like a laser in a CD player.
The laser can be written to a fine line of 5 microns and controlled by a computer so that the film can record digital data and then read the digital data back to the computer.
Traditional microfilm can be written by laser, but it is sensitive to sunlight and requires wet chemical treatment.
This new microfilm is based on a liquid crystal that is much higher than what is used in conventional displays.
It is solid at room temperature and has two solid forms: above a certain temperature, called "clear" temperature, bar-
The shape molecules of the crystal are arranged in a random direction, and the crystal looks clear.
At this temperature, molecules form small "regions" arranged with each other ".
The shape looks white.
There is enough contrast between transparent and opaque forms that allow liquid crystals to store images and text.
If an area is cooled and heated, it will "freeze" in a clear state ".
But if it cools down slowly, it reverts to an opaque state-so it's erasable.
Changing the laser power or writing speed creates a "gray" tone, partly between opaque and transparent.
Two universities and three companies working together on this project have developed two liquid crystals with higher melting points by connecting their rods-
To shape molecules into longer chains.
Their removal temperature is between 100 and 240 °c for solid heatingstate laser.
Crystals must have a high clearance temperature so that the film is not accidentally erased-100 °c is enough for most applications, such as storing important files.
By heating on the hot plate, the entire film can be erased and reused.
GuusMohlmann, an Akzo electronics company based in Arnhem, the Netherlands, says the crystal can withstand about a thousand erasers.
Microfilm is made by depositing solid liquid crystals from 3 to 7 microns on PET, and this transparent plastic is made into some carbonated beverage bottles as a support.
A dye developed by the Department of color chemistry at the University of Leeds is added, which absorbs photons from the laser and converts energy into heat.
A laser that converts energy into heat.