Form factor (mobile phones)

The form factor of a mobile phone is its size, shape, and style, as well as the layout and position of its major components.

With one non-movable section

Bar

A bar (also known as a slab, block, candybar) phone takes the shape of a cuboid, usually with rounded corners and/or edges. The name is derived from the rough resemblance to a chocolate bar in size and shape. This form factor is widely used by a variety of manufacturers, such as Nokia and Sony Ericsson. Bar-type smartphones commonly have the screen and keypad on a single face. Sony had a well-known 'Mars Bar' phone model CM-H333 in 1993.

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  A Nokia E51, a typical bar phone
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  Sony Ericsson W800i, released 2005
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  Siemens S25 from 1999
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  Nokia 7600 in an unusual bar shape

Keyboard bars

These are variants of bars that have a full QWERTY keyboard on the front. While they are technically the same as a regular bar phone, the keyboard and all the buttons make them look significantly different. Devices like these were popular in the mid- to late-2000s, but lost popularity afterwards. The BlackBerry line from Research In Motion (RIM) was particularly popular and influential in this category.

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  Palm Treo 650
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  Motorola Q
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  Nokia E61 released 2006
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  A BlackBerry Curve 8310 from 2007
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  Nokia C3-00 from 2010
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  BlackBerry Q10, released 2013

Brick

"Brick" is a slang term used to refer to large, outdated rectangular phones, typically early devices with large batteries and electronics. Such early phones, such as the Motorola DynaTAC, have been displaced by newer smaller models which offer greater portability thanks to smaller antennas and slimmer battery packs.

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  A Motorola DynaTAC 8000X, a brick phone from 1984
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  A Mobira Cityman 450, a brick phone from 1985
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  NEC P9100, a Japanese brick from 1988

However, "brick" has more recently been applied to older phone models in general, including non-bar form factors (flip, slider, swivel, etc.), and even early touchscreen phones as well, due to their size and relative lack of functionality compared to current models on the market.

The term "brick" has also expanded beyond smartphones to include most non-working consumer electronics, including a game console, router, or other device, that, due to a serious misconfiguration, corrupted firmware, or a hardware problem, can no longer function, hence, is as technologically useful as a brick. The term derives from the vaguely cuboid shape of many electronic devices (and their detachable power supplies) and the suggestion that the device can function only as a lifeless, square object, paperweight or doorstop. This term is commonly used as a verb. For example, "I bricked my MP3 player when I tried to modify its firmware." It can also be used as a noun, for example, "If it's corrupted and you apply using fastboot, your device is a brick." In the common usage of the term, "bricking" suggests that the damage is so serious as to have rendered the device permanently unusable.

Slate

A slate is a smartphone form with few to no physical buttons, instead relying upon a touchscreen and an onscreen keyboard. The first commercially available touchscreen phone was a brick phone, the IBM Simon Personal Communicator, released in 1994. The iPhone, which was released in 2007, is largely responsible for the influence and achievement of this design as it is currently conceived.

Some unusual "slate" designs include that of LG New Chocolate (BL40), or the Samsung Galaxy Round, which is curved.

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  HTC Magician, a pre-contemporary slate from 2004.
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  LG Prada, a slate phone from 2006.
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  Samsung Tocco Lite slate from 2009
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  An iPhone 4S, a slate phone from 2011.
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  A set of Nokia/Microsoft Lumia slate smartphones

Phablet

Main article: phablet

The phablet or smartlet is a subset of the slate/touchscreen. A portmanteau of the words phone and tablet, phablets are a class of mobile device designed to combine or straddle the size of a slate smartphone together with a tablet. Phablets typically have screens that measure (diagonally) greater than 5.3 inches, and are considerably larger than most high-end slate smartphones of the time (i.e. the Samsung Galaxy Note II smartlet versus the Samsung Galaxy SIII smartphone), which have to be 5.2 inches or less to be known as a smartphone, though significantly smaller than tablets (which must be 7 inches or above to be considered as such).

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  Samsung Galaxy Note 10, a modern Android phablet
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  BlackBerry Z30, a BlackBerry 10 touchscreen smartphone
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  Nokia Lumia 1520, a Windows Phone phablet

Multi-screen

The multi-screen is of basically the slate form factor, but with two touchscreens.

Some have a small separate screen above the main screens, the LG V10 and LG V20.

Other multi-screen form factors has screens on both sides of the phone. In the case of Yotaphone and Siam 7X, they have normal touchscreens on the front, but on the backside is an e-ink screen, which enables using the cases in a fashion similar to reading a book.

The presence of the front camera for taking selfies has been an essential feature in smartphones, however, it is a difficulty to achieve a bezelless screen as is the trend in the later 2010s. The Nubia X, Nubia Z20 and Vivo NEX Dual Display have solved this combining the use of the main camera and a smaller second rear screen, eliminating the front camera.

Taco

The taco form factor was popularized by the Nokia N-Gage, released in 2003. It was widely known as the plastic taco for its taco-shape and the placement of microphones on the side of the device, which, when one talks into the microphone, gives the appearance of eating a taco. Other models include Nokia 3300 and Nokia 5510.

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  N-Gage QD

Wearables

Smartwatch

Main article: Smartwatch

A smartphone in the form of a wristwatch is typically referred to as a smartwatch or watch phone.

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  The LG GD910 watch phone from 2009
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  The Z1 Android watch phone, smartphone in the form of a wristwatch

Wrapped-around display

Xiaomi revealed Mi MIX Alpha, a smartphone with a display that surrounds almost entirely its body, only interrupted in the back part by a column that contains the cameras. Back part of display can be used as viewfinder for selfies and videocalls.

With movable sections

Flip

Main article: Flip (form)

A flip or clamshell phone consists of two or more sections that are connected by hinges, allowing the phone to flip open then fold closed in order to become more compact. When flipped open, the phone's screen and keyboard are available. When flipped shut, the phone becomes much smaller and more portable than when it is opened for use.

Motorola was once owner of a trademark for the term flip phone, but the term flip phone has become genericized and used more frequently than clamshell in colloquial speech. Motorola was the manufacturer of the famed StarTAC flip phone in the 1990s, as well as the RAZR in the mid-2000s. There were also flip "down" phones, like the Motorola MicroTAC series and was also widely used by Ericsson.

In 2010, Motorola introduced a different kind of flip phone with its Backflip smartphone. When closed, one side is the screen and the other is a physical QWERTY keyboard. The hinge is on a long edge of the phone instead of a short edge, and when flipped out the screen is above the keyboard.

Another unusual flip form was seen on the luxury Serene, a partnership between Samsung and Bang & Olufsen.

Clamshell came to be used as generic for this form factor. Flip phone referred to phones that opened on the vertical axis. As clamshells disappeared from the market, the terms again became disambiguated.

By the mid-2000s, "flip" designs reached the peak of their availability and declined afterwards, being replaced by sliders which in turn were completely replaced by slate smartphones.

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  The Motorola StarTAC, the original flip-up phone
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  Kyocera 6035 "flip down" phone
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  Palm Treo 300, unusual flip-up form
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  Japanese NTT DoCoMo D506i flip phone manufactured by Mitsubishi
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  The Sony Ericsson W350, last unusual flip-down phone

Dual-touchscreen

Main article: Dual-touchscreen

In April 2011, Kyocera International released the Kyocera Echo smartphone with two 3.5" screens. The phone's primary display could lay on top of the second display, reducing its size. In November 2017, ZTE announced the Axon M. The screens could fold to either have two forward facing screens, or one forward and one rear facing screen. The combined display size is 6.75-inch when unfolded. The second screen allows the Axon M's single camera to be both rear and forward facing, as well as acting as a kickstand or tripod.

Foldable screen

Main article: Foldable smartphone

Due to advances in display technology, as of 2010s, OLED screens can be manufactured on a flexible, plastic substrate. Glass is no longer needed, allowing the displays to be rolled, bent and folded. This makes new form factors possible in mobile phones. In September 2017, Samsung confirmed a new series of foldable smartphone. In November 2018, it is revealed that the new phone—Samsung Galaxy Fold's combined display size is 7.4-inch. Other manufacturers, such as Huawei and Xiaomi have also announced phones with foldable displays. In November 2019, Motorola officially unveiled its horizontal-folding Motorola Razr.

Flip up Camera

Asus, in the Zenfone 6 smartphone, manages to implement an all screen front, prescinding from a dedicated selfie camera, thanks to main cameras are housed in a motorized flip-up module, that rotates 180 degrees to focus the front part.

Slider

A slider is composed of usually two, but sometimes more, sections that slide past each other on rails. Most slider phones have a display segment which houses the device's screen, while another segment contains the keypad or keyboard and slides out for use. The goal of a sliding form factor is to allow the operator to take advantage of full physical keyboards or keypads, without sacrificing portability, by retracting them into the phone when they are not in use. Many different companies have developed smartphones that slide: Samsung has the Corby and BlackBerry has the Torch.

The Siemens SL10 was one of the first slider smartphones in 1999. Some phones have an automatic slider built in that deploys the keypad. Many phones pop out their keypad segments as soon as the user begins to slide the phone apart. Unique models are the 2-way slider where sliding up or down provides distinct functions: the Nokia N85 or Nokia N95 are examples of this.

A version of the slider form factor, the side slider or QWERTY slider, uses vertical access of the keyboard on the bottom segment. The side slider form factor is primarily used to facilitate faster access to the keyboard with both thumbs. The Motorola Photon Q, Danger Hiptop, Sony Mylo, and HTC Touch Pro are four primary examples.

Some unusual sliders have also been made, such as the Nokia 7280 modelled like a lipstick, or the Samsung SGH-F520 from 2007 which slides two ways with a QWERTY keyboard.

Sliders supplanted the flip form, since they allowed manufacturers to pack more keypad buttons and features (especially the side slider or QWERTY slider) into the same form factor, while touchscreen interfaces were still in their infancy. By the late-2000s, "slider" designs reached the peak of their popularity and declined afterwards, being completely replaced by slate form factors with well-developed touch interfaces. In 2015, BlackBerry Limited (previously RIM) released the BlackBerry Priv, the first mainstream slider phone in several years (based on Android, not the Blackberry operating system they sold so far).

As 2018, manufacturers are trying to develop bezelless smartphones, being the greatest difficulty the presence of front cameras and face recognition sensors, while most brands expand display real state conserving a notch, some departs from that approach returning to the slider form factor, in models like Xiaomi Mi Mix 3, Huawei Honor Magic 2 and Lenovo Z5 Pro.

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  Samsung SGH-D500, standard slider
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  T-Mobile Sidekick II, side slider
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  BlackBerry Torch 9800, a tall slider
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  Nokia 7110, with a keypad cover slider
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  Nokia N95, a dual slider
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  Nokia 7280, slider that hide camera
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  Motorola Droid, a wide QWERTY slider
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  Nokia E7, QWERTY slider that angles up
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  Xperia Play, a handheld game console slider

Pop up camera

Phones like Oppo Find X and Vivo Nex hide front cameras within the body of the devices in motorized pop-up modules to create a bezelless front face fully occupied by screens without any cutout while keeping a front-facing camera that can up when required. Vivo V15 Pro and Centric S1 also come with pop up camera mechanism for selfie camera.

Swivel

A swivel phone is composed of multiple, usually two, segments, which swivel past each other about a sagital axis (most of the time). Use of the swiveling form factor has similar goals to that of the slider, but this form factor is less widely used. Samples are, LG U900 + 960 + V9000, Motorola Flipout + V70 + V80, Nokia 7370, Siemens SK65, Samsung Juke + Samsung SGH-X830, and Sony Ericsson S700i + W600.

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  Sony Ericsson W550i, a swivel phone
• Motorola V70
  Motorola V70
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  The Motorola Flipout, a swivel phone

Some implementations, that do not use the sagital axis, are presenting in phones like Nokia 3250 and Oppo N1, with twistable componentes: a keyboard, and main camera (doubling as a selfie one), respectively.

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  Nokia 3250, with twistable keypad
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  Oppo N1, has a twistable main camera that is used for selfies when rotates.

Mixed

Some mobile phones use more than one form, such as the Nokia N90, Philips 968, Sharp SX862, Samsung SGH-P910, Amoi 2560, Samsung Alias series or Panasonic FOMA P900iV, which use both a swivel and a flip axis.

Other examples include the Sierra Wireless Voq which combines a candybar with a keyboard "side-flip"; the Nokia Communicator series which utilise both a candybar and a clamshell with a QWERTY keyboard; or the Siemens SK65 which is a swivel candybar with a QWERTY keyboard.

Bezelless Samsung A80 only has rear cameras that are housed in a motorized module, using a combination of slider and swivel they achieve the rotation to the front to be used for selfies.

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  Nokia E70, unusual candybar/flip form with a QWERTY keyboard
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  Nokia N93, mixed swivel/flip
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  Docomo Panasonic P906i, W-Open
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  KDDI Sharp W61SH (Japan), mixed swivel/flip

External links

• Many illustrations of standard and mixed form factors
• HTC Wallaby specification