Retina display
Apple's branded high-pixel-density displays with variable resolution thresholds.
Retina display is Apple Inc.’s brand name for a series of LCD and OLED screens that pack more pixels per inch than the company’s earlier displays. Apple trademarked the term “Retina” for computers and mobile devices with the U.S. Patent and Trademark Office in 2012 and with the Canadian Intellectual Property Office in 2014. The display first appeared in 2010 on the iPhone 4 and iPod Touch (4th generation), then on the iPad (3rd generation). In those models, each pixel from earlier screens (like the iPhone 3GS, iPod Touch 3rd generation, and iPad 2) was replaced by four smaller pixels, and the user interface was scaled up to fill them—a mode Apple calls HiDPI. Essentially, one logical pixel corresponds to four physical pixels. For even denser screens, such as those in the iPhone 6 Plus and iPhone X, the scale factor triples. This approach lets the CPU process a smaller amount of data to calculate element positions, while the GPU renders those elements using high-quality assets. The result is crisper text and images.
Since then, Retina displays have spread to nearly all Apple product lines, including Apple Watch, iPhone, iPod Touch, iPad, iPad Mini, iPad Air, iPad Pro, MacBook, MacBook Neo, MacBook Air, MacBook Pro, iMac, and monitors like the Studio Display, Pro Display XDR, and Studio Display XDR—some of which never had non-Retina versions. Apple uses different marketing names to distinguish among LCD and OLED screens with varying resolutions, contrast, color reproduction, or refresh rates. For example, the iPhone XR, iPad Air (4th generation), iPad Mini (6th generation), and iPad Pro (3rd generation and later) are called Liquid Retina displays, while the iMac uses Retina 4.5K display.
Retina displays don’t have a single fixed pixel density; instead, the density changes based on how far away a user typically holds the device. Smaller devices worn or held closer to the eyes—like watches and phones—need very high pixel densities so individual pixels are invisible. For screens viewed from farther away, like notebook or desktop monitors, less density is required to achieve the same angular resolution. Later products have added improvements like larger screen sizes, higher contrast ratios, or greater pixel densities.
- Debut year
- 2010
- First devices
- iPhone 4 and iPod Touch (4th generation)
- Ppi threshold quote
- about 300 ppi for a device held 10 to 12 inches from the eye (Steve Jobs)
- Angular pixel density threshold
- 52–63 PPD
- Trademark approval us
- 2012
- Trademark approval canada
- 2014
- Iphone 6 plus ppi
- 401 ppi
Lore & Background
The Retina display debuted in 2010 with the iPhone 4 and the iPod Touch (4th generation), and later the iPad (3rd generation). In these early implementations, each screen pixel of the iPhone 3GS, iPod Touch (3rd generation), and iPad 2 was replaced by four smaller pixels, and the user interface scaled up to fill in the extra pixels, a mode Apple calls HiDPI mode. The scale factor is tripled for devices with even higher pixel densities, such as the iPhone 6 Plus and iPhone X. The advantage of this equation is that the CPU "sees" a small portion of the data and calculates the relative positions of each element, and the GPU renders these elements with high-quality assets.
Apple uses various marketing terms to differentiate between its LCD and OLED displays having various resolutions, contrast levels, color reproduction, or refresh rates. It is known as Liquid Retina display for the iPhone XR, iPad Air (4th generation), iPad Mini (6th generation), iPad Pro (3rd generation) and later models, and Retina 4.5K display for the iMac. Later products have had additional improvements, such as an increase in the screen size, contrast ratio, or pixel density. Apple has used names such as Retina HD display, Retina 5K display, Super Retina HD display, Super Retina XDR display, and Liquid Retina display for various iterations.
When introducing the iPhone 4, Steve Jobs said the density of pixels needed for a Retina display is about 300 ppi for a device held 10 to 12 inches from the eye. This definition includes the viewing distance, because moving the eye closer to the display makes it easier to see detail up close, and moving away makes it harder. One metric that takes into account both pixel density and viewing distance is angular pixel density, typically expressed in pixels per degree (PPD). Based on Jobs' statement, the threshold for a Retina display is an angular pixel density of 52–63 PPD.
Reader's Guide
The significance of Retina display lies in its approach to eliminating the appearance of graininess on a screen, particularly for complex languages such as Arabic, Hebrew, and CJKV. Apple's definition is not a fixed pixel density but depends on viewing distance, which has been both praised and challenged. Many authors have challenged Apple's claim: Raymond Soneira of DisplayMate Technologies argued that the human retina requires at least 477 pixels per inch at 12 inches for pixels to become imperceptible, corresponding to 100 PPD. John Brownlee stated the threshold to discern individual pixels is between 0.3 and 0.4 arcminutes (150–200 PPD). Others have defended Apple: astronomer Phil Plait argued that a resolution of 0.6 arcminutes corresponds to "perfect eyesight" but that a typical person has about 1 arcmin resolution (60 PPD), and that what Jobs said was fine as the iPhone 4S's resolution is better than 1 arcmin. Retinal neuroscientist Bryan Jones cited a paper calculating 0.78 arcminutes per cycle (77 PPD) and stated that optics may degrade image quality, giving the commonly accepted resolution of 1 arcminute. A 2024 study found the eye had resolution limits of 94 PPD for foveal achromatic vision, 89 PPD for red–green patterns, and 53 PPD for yellow–violet patterns. Reviews of Apple devices with Retina displays have generally been positive on technical grounds, with comments describing it as a considerable improvement on earlier screens and praising Apple for driving third-party application support for high-resolution displays more effectively than on Windows.
Did You Know?
- Apple's trademark applications for 'Retina' were approved in the US in 2012 and in Canada in 2014.
- The iPhone 6 Plus, with 401 ppi, was marketed as a Retina HD display.
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