Retina display is a branded series of LCDs and OLED displays by Apple Inc. that have a higher pixel density than traditional displays. Pixels per inch (ppi) and pixels per centimetre (ppcm or pixels/cm) are measurements of the pixel density of an electronic image device. Horizontal and vertical density are usually the same, as most devices have square pixels, but differ on devices that have non-square pixels. The goal of Retina displays is to make the text and images crisper.

The Retina display debuted in 2010 with the iPhone 4 and the iPod Touch (4th Generation), and later the iPad (3rd generation)

The Retina display has since expanded to most Apple product lines, such as Apple Watch, iPhone, iPod Touch, iPad, iPad Mini, iPad Air, iPad Pro, MacBook, MacBook Air, MacBook Pro, iMac, and Apple’s computer monitors such as the Studio Display and Pro Display XDR, some of which have never had non-Retina displays.

Apple’s Retina displays do not have a fixed minimum pixel density, but vary depending on and at what distance the user would typically be viewing the screen.

The displays are manufactured worldwide by different suppliers. Currently, the iPad’s display comes from Samsung,[12] while the MacBook Pro and iPod Touch displays are made by LG Display[13] and Japan Display Inc.[14] There was a shift of display technology from twisted nematic (TN) liquid-crystal displays (LCDs) to in-plane switching (IPS) LCDs starting with the iPhone 4 models in June 2010. Apple markets the following devices as having Retina, Retina HD, Liquid Retina, Liquid Retina XDR, Super Retina HD, Super Retina XDR, Ultra Retina XDR or Retina 4K, 5K or 6K displays.

Ultra Retina XDR

This type of display is on the iPad Pro (M4). Apple says that the Ultra Retina XDR display is the best OLED display that has ever shipped in a device of its kind. The Ultra Retina XDR display delivers incredibly accurate color, high brightness, High Dynamic Range, and an optimal viewing experience.