All the breakthrough technology in iPhone 4 is situated between two glossy panels of aluminosilicate glass — the same type of glass used in the windshields of helicopters and high-speed trains. Chemically strengthened to be 20 times stiffer and 30 times harder than plastic, the glass is ultradurable and more scratch resistant than ever. It’s also recyclable.
The 960-by-640 backlit LCD display boasts a pixel density of 326 pixels per inch, making it the highest-resolution phone screen ever. To achieve this, Apple engineers developed pixels so small — a mere 78 micrometers across — that the human eye can’t distinguish individual pixels. That makes text remarkably sharp and graphics incredibly vivid. IPS technology also provides excellent color and contrast from almost any viewing angle.