If you rent a lot ofDVDs , former fees are an unfortunate fact of life . And if you ’re not the most organized person around , they might even figure conspicuously in your monthly budget . Forget to return " Battlefield Earth " for a week , and you’ll pay more in late fees than the DVD is worth . This , of course , was the video store ’s plan all along .
If this sounds like you , then take heart – the Mar of engineering may have descend to the rescue . A company calledFlexplay Technologieshas introduced a new character of videodisc that trade at rental prices but never need to be come back .
A Flexplay ® DVD takes attention of the " rental period " itself – it attain a chemic stopwatch when you start the package , and when your meter is up ( in 48 hour , say ) , the disk hold on working . Recycle it or turn it into a coaster and regard it returned . And because you do n’t need a received rental store set - up , just about any store ( even restaurants ) could potentially sell the DVDs .
It ’s an interesting melodic theme , and the engineering behind it is pretty interesting , too . In this article , we ’ll find out how these videodisk do what they do .
Normal DVDs
In most respects , a Flexplay DVD is just like any other videodisc – it has only one major addition .
The basic idea behind stock videodisk is very simple . The images and strait that make up a DVD disc are encode digitally – asbitsof information ( strings of ace and 0s – seeHow Analog and Digital Recording Worksfor more information ) .
The videodisk manufacturers put all this digital data onto a disk as a pattern of " extrusion " ( raised areas ) and " lands " ( flat areas ) , arrange in a very long rails , spiraled around the phonograph recording . The manufacture machinery presses the bumps into layers of polycarbonate plastic and then shin a reflective metal layer onto the plastic .
UnlikeCDs , DVDs in reality have two reflective layers – an inner brooding bed , and a semi - lucid out broody layer – with two dissimilar data track ( so the disc can hold more info ) . The manufacture machinery draw together the two layer together usingresin adhesive , which hardens into solid plastic , securing the two sides into a single record .
When you play a videodisc , the videodisk actor shines a narrow laser beam over the data point raceway . The laser hits the bumps and flatbed on both pondering layer , and the beam recoil back to anopto - electronic sensor(basically , a light reader ) . Because they are different build , the jut and flats ponder light other than . The sensor detects the difference , reading the radiation pattern encoded onto the disc . ( SeeHow DVDs Workfor more info . )
Flexplay ’s discs play on the nose the same way , but they admit a specialised layer of material in the disc , in front of the inner reflective layer . This layer is the Francis Scott Key to the platter ’s circumscribed play time , as we ’ll see in the next section .
The Flexplay Twist
The secret to Flexplay disk is an extra layer lend to a standard DVD structure . This specialized bed includes a chemical compound that pronto combine with atomic number 8 in the atmospheric state to form a raw chemical compound .
While the original chemical compound is gossamer , the newfangled chemical compound is opaque . When the level is diaphanous , the laser passes straight through to the pensive level , reading the videodisc as it normally would . When the bed is opaque , the laser ca n’t make it to the inner ruminative layer , so the disc is in effect blank to the DVD player .
The disc come in anairtightpackage , so atomic number 8 ca n’t get to the additional layer . When you launch the packaging , the O in the atmosphere starts a chemic chemical reaction . The particular chemicals are balanced so that the reaction proceeds very slowly at first , during the " rental period , " and then speeds up . When the reaction speeds up , the specialized layer go from clear to cloudy . By vary the accurate chemical mixing in the this add level , Flexplay can adjust the length of the rental period of time .
The airtight package slows the response down to the point that the DVD will persist amply operable for at least a year .
you could actually see the process at work in the disc . When you first give the airtight package , the disc has a reddish coloring material . When the compound change , the red color turns to black-market .
To make these change videodisc easy to mass green goods , Flexplay demand a path to add the specialized layer without overhauling the standard manufacture process . As we saw in the last section , the two data track start out on two freestanding discs , which the manufacturing machinery bail together with resin adhesive . To make a Flexplay DVD , the disc manufacturing business supersede the normal adhesive with Flexplay ’s proprietary adhesive . This adhesive hardens to form the specialized plastic layer that clouds up over 48 hours .
It ’s anybody ’s supposition how far this engineering science will go . The program does n’t have to edge out traditional television stores to be a success – it just needs to find a core audience who favor its unique letting system . Only meter will narrate .
For more data about Flexplay DVDs and related engineering , check out the golf links in the next section .
