It is a form factor found mainly in cellphones in the electronics market. There are typically two distinct sections of the device that fold together via a hinge. When the device is open, it is up and ready to be used, and provides more surface area then when closed. When the unit is closed, the interface components such as keys and display are protected and the device is shorter, making for easier to be carried and stored. A disadvantage of the flip unit is the connecting hinge, which is prone to fatigue or failure.
This type of device is most closely associated with the mobile phone market; Motorola used to have a trademark on the term â€œflip phone,â€ but now, the term has become synonymous with most phones that flip open. Notably, the phrase â€œflip phoneâ€ seems to roll off the tongue more easily than clamshell phone.
The design has been used in other areas, such as in some landline phones, cordless ones in particular. Other devices that use the clamshell form are laptops, notebooks, the Game Boy Advance SP handheld game system and the popular Nintendo DS; although these devices are less frequently described as flip or clamshell compared to cell phones.
The Flip form factor was first implemented by laptop maker GRiD for their Compass model in 1982. The first Motorola model to support this design was the StarTAC, created in 1996, though GTE held the trademark for its Flip Phone from the 1970s until 1993. The design has since been copied by nearly all mobile phone makers at some point, with many still mass-producing flip-style phones. Motorola is perhaps best known for its clamshell models such as the RAZR.
Clamshells were, as of early 2009, the most popular form factor for cell phones in the US. However, they have been losing popularity to phones that now have slide-out keyboards and touchscreen displays.
Other devices that use the clamshell form factor include pocket watches, waffle irons, some toasters, and of courseâ€¦ the George Foreman Grill.
Image Caption: NTT DoCoMo FOMA F880iES is a Japanese mobile telephone that was designed for the aged who cannot use many functional mobile telephones. Credit: Qurren/Wikipedia(CC BY-SA 3.0)