A flip phone demonstrating clamshell design, open (left) and closed (right)
The clamshell form factor is based on the hinged design of the clam.
Two schools of clamshell design: bio-design influenced Apple iBook (1999) and Bento box-like ThinkPad T43p (2005)

A clamshell design is a kind of form factor for electronic devices in the shape of a clamshell. Mobile phones, handheld game consoles, and especially laptops, are often designed like clamshells. Clamshell devices are usually made of two sections connected by a hinge, each section containing either a flat panel display or an alphanumeric keyboard/keypad, which can fold into contact together like a bivalve shell.

A clamshell mobile phone is sometimes also called a flip phone, especially if the hinge is on the short edge. If the hinge is on a long edge (e.g., Nokia Communicators), the device is more likely to be called just a "clamshell" rather than a flip phone.[citation needed]

Generally speaking, the interface components such as keys and display are kept inside the closed clamshell, protecting them from damage and unintentional use while also making the device shorter or narrower so it is easier to carry around. In many cases, opening the clamshell offers more surface area than when the device is closed, allowing interface components to be larger and easier to use than on devices which do not flip open. A disadvantage of the clamshell design is the connecting hinge, which is prone to fatigue or failure.[citation needed]


The clamshell form factor is most closely associated with the cell phone market, as Motorola used to have a trademark on the term "flip phone",[1] but the term "flip phone" has become genericized to be used more frequently than "clamshell" in colloquial speech.[citation needed]


Brionvega TS 502 radio, Museum of science and technology, Milan (1963)
Grillo telephone, Museum of science and technology, Milan (1965)
Brionvega Soundbook portable radio cassette player, Museum of science and technology, Milan (1974)

A "flip phone" like communication device appears in chapter 3 of Armageddon 2419 A.D., a science fiction novella by Philip Francis Nowlan, which was first published in the August 1928 issue of the pulp magazine Amazing Stories: "Alan took a compact packet about six inches square from a holster attached to her belt and handed it to Wilma. So far as I could see, it had no special receiver for the ear. Wilma merely threw back a lid, as though she was opening a book, and began to talk. The voice that came back from the machine was as audible as her own."[2] Also from science fiction, Star Trek: The Original Series featured an clamshell instrument called the "Communicator", a regular plot device, which influenced development of early clamshell mobile phones, such as the Motorola StarTAC.[3]

Early examples of the form factor's use in electronics include the 1963 Brionvega TS 502 radio, the Grillo telephone, which first appeared in Italy in the mid 1960s, and the Soundbook portable radio cassette player, which was introduced in 1974. The form factor was first used for a portable computer in 1982 by the laptop manufacturer GRiD (who had the patents on the idea at the time)[4][5] for their Compass model.[6][7] In 1985, the Ampere WS-1 laptop used a modern clamshell design.[8][9]

The first Motorola model to support the clamshell design was the MicroTAC, created in 1989, although General Telephone & Electronics held the trademark from the 1970s for its Flip-Phone (one of the first small handheld electronic phones), until 1993.[10][11][12][13] Flip phones became popular in the late 1990s, and this factor lasted until the early 2010s. The clamshell form factor began to experience a decline in popularity in the late 2000s and early 2010s, due to the increasing popularity of touchscreen smartphones such as the iPhone, which use a slate-like form factor and large, non-folding screens. Clamshells remain a predominant form factor for feature phones—which remain popular among specialized audiences who prefer their simplicity or durability over smartphones.[14][15] Samsung also released a low-end smartphone in South Korea known as the Galaxy Folder, which has a flip phone design and keypad reminiscent of feature phones whilst running Android.[16]

Samsung Galaxy Z foldable smartphones uses clamshell design

In 2019, a new trend of foldable smartphones using rollable OLED displays began to emerge: the Samsung Galaxy Fold uses a clamshell form factor with a vertical fold and a small secondary screen on its cover, and exposing a larger, tablet-like screen when opened.[17][18] Motorola unveiled a reimagining of the Motorola Razr in November 2019, which uses a foldable display and a clamshell design reminiscent of its namesake line of feature phones.[19][20]


Clamshell bonnet of a Jaguar E-Type (1966)

In automotive design, a clamshell bonnet or clamshell hood is a design where the engine cover also incorporates all or part of one of the wings (fenders). It is sometimes found in a car with a separate chassis such as a Triumph Herald or in cars based on a spaceframe where the bodywork is lightweight and carries no significant loading, such as the Ford GT40 and Ferrari Enzo, where the whole rear end can be lifted to access the engine compartment and suspension system. It is also sometimes seen in unibody cars, albeit much more rarely – such as the BMW Minis and Alfa Romeo GTV.

It is also an informal name for General Motors full-size station wagons, manufactured from 1971 to 1976, that featured a complex, two-piece "disappearing" tailgate, officially known as the "Glide Away" tailgate.[21]

Other uses

Nintendo Game Boy Advance SP (2003)

Besides smartphones, devices using the flip form include laptop computers, subnotebooks, the Game Boy Advance SP, Nintendo DS, and Nintendo 3DS, though these are less frequently described as "flip" or "clamshell" compared to smartphones.

Other appliances like pocket watches, waffle irons, sandwich toasters, krumkake irons, and the George Foreman Grill have long utilised a clamshell design.

Bookbinders build archival "clamshell" boxes called Solander cases, in which valuable books or loose papers can be protected from light and dust.

See also


  1. ^ US trademark #2157939, cancelled February 26, 2005
  2. ^ [1] Archived 2021-05-25 at the Wayback Machine Armageddon 2419 A.D.
  3. ^ Vaughan, Kendra (27 July 2023). "Infinite Diversity or Infinite Opportunity: a Look at Star Trek and its Cultural Influence". History in the Making. 16.
  4. ^ U.S. patent D280511
  5. ^ U.S. patent 4,571,456
  6. ^ Marsh, Allison (2020-05-29). "NASA's Original Laptop: The GRiD Compass". IEEE Spectrum. Retrieved 2022-10-02.
  7. ^ "GRiD Compass Laptop Computer Prototype". Cooper Hewitt, Smithsonian Design Museum. Retrieved 2022-10-03.
  8. ^ Japanese PCs (1984) Archived 2017-07-07 at the Wayback Machine (13:13), Computer Chronicles
  9. ^ Bob Armstrong, Archived 2008-05-13 at the Wayback Machine
  10. ^ Tynan, Dan (2005-12-24). "The 50 Greatest Gadgets of the Past 50 Years". PC World. p. 2. Archived from the original on 2008-07-02. Retrieved 2006-09-10.
  11. ^ "Sams Telephone Pictures Collection – Post Liberalisation". Archived from the original on 2008-06-10. Retrieved 2008-07-07.
  12. ^ "Motorola tries to secure flip phone trademark, designer gets caught in battle". Mobile Phone News. 1996. Archived from the original on 2012-06-29. Retrieved 2008-07-07.
  13. ^ "Nokia takes on clamshell rivals". BBC News. 2004-06-14. Archived from the original on 2010-01-09. Retrieved 2010-05-02.
  14. ^ Abrahams, Rebecca (2014-12-02). "Is Hollywood Going Back to Flip Phones?". The Huffington Post. Archived from the original on 2017-05-13. Retrieved 2014-12-31.
  15. ^ "High-profile stars find fashion in old-school phone tech". Business Insider Australia. December 2, 2014. Archived from the original on 2014-12-30. Retrieved 2014-12-31.
  16. ^ Segan, Sascha (March 22, 2017). "Samsung Galaxy Folder is a Flip Phone You'd Actually Want". PCMag. Archived from the original on 20 April 2019. Retrieved 20 April 2019.
  17. ^ Knapp, Mark (29 October 2019). "Samsung's clamshell foldable design is the future of the Galaxy Fold". TechRadar. Archived from the original on 2021-09-09. Retrieved 2019-11-15.
  18. ^ Dolcourt, Jessica. "Galaxy Fold vs. Mate X: Battle of the foldable phones". CNET. Archived from the original on 2019-10-28. Retrieved 2019-11-15.
  19. ^ Gartenberg, Chaim (2019-11-13). "Motorola resurrects the Razr as a foldable Android smartphone". The Verge. Archived from the original on 2020-01-08. Retrieved 2019-11-14.
  20. ^ Lowe, Mike (2019-11-14). "Motorola Razr review: The flip phone is back for 2019". Pocket-lint. Archived from the original on 2020-02-01. Retrieved 2019-11-14.
  21. ^ "How Oldsmobile Cars Work". HowStuffWorks. 20 June 2007. Archived from the original on 4 August 2020. Retrieved 14 April 2019.