The iPhone 4 is intended for audio and video calling, consumption of several forms of media, such as music, periodicals, movies, books, games and others, or internet based applications or activities like e-mail or browsing. Announced at the WWDC 2010 held at the Moscone Center in San Francisco, the iPhone 4 was released on June 24, 2010 in the United States, the United Kingdom, France, Germany and Japan.
As its predecessors, the iPhone 4 uses Apple's iOS (formerly called iPhone OS) operating system. Realizing that the operating system was no longer dedicated to the iPhone, but to all Apple touch screen based devices, the company decided to change its name into iOS. The iPhone 4, as its predecessors, runs a large variety of applications, which have to be approved by Apple itself, and obtained through their online application store called AppStore.
The phone uses a sensitive multi touch based liquid crystal display screen of 3.5 inches. Due to not being able to produce the needed amount of electrical conductivity, normal gloves and styluses do not work with the iPhone 4. However, there are special gloves and styluses that will work with the iPhone. The first thing you notice different between the iPhone 4 and an older iPhone model is the uninsulated stainless steel frame, that acts like the device's antenna. The phone's internal components are situated between two panels of chemical strengthening of the aluminum silicate glass. It runs Apple's A4 processor and 512 MB of eDRAM. This is twice as good as the previous iPhone, and four times better than te original iPhone. Some of the people that bought the iPhone 4 complained about it lacking signal when held in certain ways, mostly when held in the left hand, because the problem with the antenna is located in the bottom left corner (when the antenna is pulled off).
Apple has offered the customers that were experiencing this problem a free casing until September 30, 2010, or a complete refund within 30 days of purchase. After the date of September 30, 2010, people with this problem can only fix it by calling to AppleCare. The display present on the Apple iPhone 4 is a 3.5 inch LCD TFT LED Backlit capacitive touchscreen with a pixel density of 326 ppi (pixels per inch). Each pixel is 78 micrometers in width and the display ratio of the screen is of 800:1.The iPhone 4's screen was marketed as the Retine Display and designed by Apple, but it was produced by LG.