Clamshell design

A clamshell phone, open

A clamshell phone, closed

Opened Sharp Electronic Organizer (sold as Sharp Wizard in the US) model QZ-770.

Closed and open Ericsson T39 was a compact flip phone, not clamshell

The flip or clamshell is an electronics form factor which is in two or more sections that fold via a hinge. If the hinge is on a long edge the device is more likely to be called clamshell than flip phone (e.g., Nokia Communicators).

When the clamshell is open, the device is ready for use. The interface components are kept inside the clamshell, which offers more surface area than when the device is closed. Interface components such as keys and display are protected when the clamshell is closed, and it is less long or wide, making the device easier to carry around. A disadvantage of the clamshell design is the connecting hinge, which is prone to fatigue or failure.

The clamshell form factor is most closely associated with the mobile phone market, as Motorola used to have a trademark on the term "flip phone", but the term "flip phone" has become genericized to be used more frequently than "Clamshell" in colloquial speech. The design is also used on some landline phones, particularly cordless phones. Other devices using the flip form include laptop computers, subnotebooks, the Game Boy Advance SP and the Nintendo DS, though these are less frequently described as "flip" or "clamshell" compared to cellular phones.

History

The form factor was first used by the laptop manufacturer GRiD (who had the patents on the idea at the time) for their Compass model in 1982.

Clamshell design of phones is generally agreed to have been inspired by the Star Trek original series communicator.

The first Motorola model to support the clamshell design was the StarTAC, created in 1996, although General Telephone & Electronics (GTE) held the trademark since the 1970s for its Flip Phone (one of the first small hand-held electronic phones), until 1993..

The design has since been copied by virtually all mobile phone manufacturers many times, with major manufacturers including Samsung and LG.

Motorola is best known for its clamshell models such as the RAZR.

The clamshell design has also been used in the Nokia Communicator series, with the first model released in 1996. Early models were very expensive and Nokia did not adopt the traditional clamshell phone design until 2004.

Clamshells were, as of early 2009, the most popular form factor for cellular phones in the U.S. However, they have been losing ground to phones with slide-out keyboards, and touchscreen “slate” phones like the iPhone.

Other uses

Cellular phones are the most popular use of the clamshell form factor. The design is also used on some landline phones, particularly cordless phones. Other devices using the flip form include laptop computers, subnotebooks, the Game Boy Advance SP and the Nintendo DS, though these are less frequently described as "flip" or "clamshell" compared to cellular phones.

Other appliances like pocket watches, waffle irons, sandwich toasters, krumkake irons and the George Foreman Grill have long utilised a clamshell design; a very similar concept is used in racing and road legal cars, like the Ford GT40 and Ferrari Enzo, where the whole rear end can be lifted to access the engine compartment and suspension system.

Bookbinders build clamshell boxes in which valuable books or loose papers can be protected from light and dust.

It is also an informal name for General Motors full-size station wagons (manufactured 1971–1976), that featured a complex, two-piece "disappearing" tailgate, officially known as the "Glide Away" tailgate.

Alternative mobile phone forms

• Bar or candybar, a slab-shaped form
• Slide, a form made of two or more parts that slide against each other
• Slate or touchscreen, a subset of the candybar form that has no buttons, instead relying upon a touchscreen and virtual QWERTY keyboard, a prominent example being the iPhone
• Swivel, a form made of two or more parts that swivel around
• Brick, an overly "bulky" form, usually an older phone that can be Flip, Bar, Slide, or Swivel, but is usually Bar
• Mobile phone form factors