Design
The iPhone 4 features a redesigned structure, designed by Jonathan Ive. Most notably, the bulges of the back panel as well as the band between the front and back are gone and have been replaced with flattened surfaces. The redesign reflects the utilitarianism and uniformity of existing Apple products, such as theiPad and the iMac. From the side, the metal structure most resembles the original iPhone, but from the rear, the black plastic evokes the iPhone 3G and 3GS. The general layout of the device remains the same. The overall dimensions of the iPhone 4 have been reduced from its predecessor. It is 4.5 inches (110 mm) high, 2.31 inches (59 mm) wide, and 0.37 inches (9.4 mm) deep, compared to the iPhone 3GS, which is 4.55 inches (116 mm) high, 2.44 inches (62 mm) wide, and 0.48 inches (12 mm) deep; making the iPhone 4 24% thinner than its predecessor, the iPhone 3GS. Steve Jobs claims that it is “the thinnest smartphone on the planet".[46] The reduced size of the device is primarily due to the externally placed antenna.
The iPhone 4 is structured around a stainless steel frame that wraps around the edge of the phone, acting both as the primary structure for the device and as the iPhone 4's antennas. This metal band features two slits on the GSM version of the phone, one at the lower left, and one at the top (and a fake slit along the lower right, to cosmetically mirror the one at the lower left) that divide the band into two antenna sections: the left section of the band serves as theBluetooth, Wi-Fi, and GPS antenna, and the right and lower sections of the band act as the antenna for GSM and UMTS connectivity. On the CDMA version of the phone, however, there are four slits in the metal band. Two at the top (on the left and right) and two at the bottom. This divides the metal band into four different segments, which like the GSM version of the phone, serves as different antennas for connectivity. The top portion of the band (divided by the top left and right slits) is for connecting to the CDMA network. The left portion of the metal band is for Bluetooth, Wi-Fi, and GPS just like the GSM version. The right side is not an antenna, but serves to cosmetically mirror the left side and also to create a similar look to the GSM version of the phone.
The internal components are situated between two panels of aluminosilicate glass, described by Apple as being "chemically strengthened to be 20 times stiffer and 30 times harder than plastic," theoretically allowing it to be more scratch resistant and durable than the previous models.[8]
In fall 2010, Pentalobular screws started to replace the Philips screws used in post-repair units in the US and in production units in Japan.[47
