How Apple got the new iMac so impossibly thin

When Apple made its second round of product announcements last month, people were focused on the big reveal: the iPad Mini. But as the newness of the device wears off (especially since it was released worldwide on Nov. 2), Apple fans are noticing some of the overlooked products from that day, and one of the things people are excited about is the new iMac.

Sure, Phil Schiller gave it some love during the announcement ("look how thin that is!" he cried to the audience), but it takes some time to absorb just how remarkable that super-thin monitor is.

[ Related: Apple announces new 13-inch MacBook Pro Retina Display ]

This begs the question, though: how does Apple manage to get it just that thin? Wired's Christina Bonnington was curious too, and has found out how the tech giant managed to back an entire 27-inch iMac into just five millimetres of thickness — without turning to OLED technology.

Optical bonding: "Apple is using optical bonding (lamination) of the [LCD] panel to a sheet of strengthened cover glass," NPD DisplaySearch analyst Paul Semeza told Wired. "This eliminates the air gap between the panel and the glass, which reduces overall thickness, and the optical bonding eliminates the reflections between the inside of the cover glass and the outside of the panel, which improves image quality."

The iPhone 5 uses a similar-sounding process in order to get its thinness, but the process for the iMac is actually simpler. Because the iMac doesn't have a touchscreen to work around, Apple could instead focus on getting the glass as thin as possible without compromising resolution or touch sensitivity. The optical bonding method also eliminates the two-millimetre air gap that normally exists between the cover glass and the actual display.

[ More Right Click: Oprah picks the Microsoft Surface as one of her 'Favourite Things' ]

Friction stir welding (FSW): Once they managed to get the cover glass that thin, the next step was to make the casing for it just as slim. Apple opted to license the patented FSW technology, which instead of melting the metal to weld it, uses a tool with a small protrusion that rotates at high speed between two overlapping metal plates, causing friction which heats and softens the surfaces. The two metal plates are then pressed together at high pressure, creating a firm bond with no weld marks. This same technology is used to create airplane wings and parts of the Space Shuttle.

No optical drive: Keen observers have probably noticed something else missing in the newest iteration of the iMac: an optical drive. With so much of Apple's focus being on iCloud and media available in the iTunes or Mac App stores, they've taken out the ability to put in a CD-ROM or DVD-ROM. If you're not prepared to go all-digital, however, Apple does offer an optical drive that plugs in via USB. The catch is, it'll cost you $80 for the privilege of holding onto your old media.

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