Differences between AMOLED, LCD, Infinity Display and Retina display

All around us we see advertisements for new smartphones, new specifications, faster processors, more RAM, various biometric sensors… and lately new types of screens. In advertisements, phone manufacturers also include information about the screen, because it is through the screen that we perform the most interactions with the device itself. And then some users find themselves confused by bombardment with various screen names. This article briefly discusses the currently available screen types for smartphones.

Let's be clear: there are only 2 types of screens

1. LED-based screens
2. LCD screens

LED

With LED screens in the background are small LEDs - red, green, and blue - and turn on and off as needed. These diodes are very small and cannot be seen with the naked eye, and the more of them on the smaller the surface, the higher the resolution, and the sharper the image.

AMOLED

That "LED" part refers to the LED (Light-emitting diode), which you already knew and saw everywhere in your environment. The letter "O" means "Organic" and refers to the organic layer that is placed between the conductors of the LED. Finally, "AM" means "Active Matrix", which is essentially a thin layer of transistors (TFT) that connects each diode and allows faster state change. So, this is an LED screen with some improvements.

Blue diodes are a problem with these screens because they are weaker than red and green ones. The solution is in the arrangement of diodes, so now the "Triangular" arrangement is used, and the blue diodes are bigger to be brighter. You can see that layout in the pictures.

Super AMOLED

They are essentially AMOLED screens except that the touch sensor is an integral part of the screen and not a special layer above. This makes this screen even thinner. Samsung uses this term for marketing purposes because it sounds much better and more advanced, so the word SUPER has to be something much better.

Infinity Display

In this case, too, we are talking about AMOLED screens, more precisely Super AMOLED screens, but there is a difference in the size of the screen with the body of the phone. The Galaxy S8 is advertised as a phone with Infinity Display but it is essentially a Super AMOLED screen.

Advantages and disadvantages of LED screens:

Advantages

• Thin and light
• Great viewing angle
• A wide range of colors
• Excellent contrast, deep blacks, strong bright colors
• Save electricity energy (when the background is black the diodes are completely turned off)

Disadvantages:

• Much more expensive and complex production (higher price)
• Blue LEDs lose light faster than others, which reduces the life of the panel
• "Burn-in" risk if part of the screen displays the same image for a long time

LCD

A completely different technology that works with liquid crystals (Liquid Crystal Display). I wrote a paper at the faculty about these screens, how they work in detail, and an article based on that paper, so read HERE.

In short: LCD screens have backlighting that shines through polarizing filters, liquid crystal, and color filters. Liquid crystals rotate when voltage is applied to them, and depending on the amount of voltage applied to the crystals, they rotate at a certain angle and thus transmit a certain amount of light. And here we have three familiar colors - red, blue, and green - in the form of filters (better known as sub-pixels) that merge into a particular color.

Super LCD

As with AMOLED, we have "Super" technology here. The term is also used for screens that have a built-in touch sensor so that there is no gap, and therefore the screen is thinner.

Retina and Retina HD

Samsung is not the only company that uses "fancy" names for marketing purposes, there is also Apple. Namely, Apple uses LCD IPS screens for its devices, but calls them "Retina" because it sounds "cool". Retina screens first appeared on iPhone 4 phones and offered a sharper image due to the higher pixel density (300 PPI). Later, Retina HD appears, which is essentially Retina (LCD IPS) but in 720p resolution.

Super Retina HD

With the advent of the iPhone X (10), Apple is also introducing its first phone with an AMOLED screen. In this case, the AMOLED screen is used only under the name Super Retina HD because it is "cool", and we have known the technology for a long time.

Advantages and disadvantages of LCD screens:

Advantages

• Great display of natural colors
• No risk of permanent "Burn-in"
• Cheaper and simpler production

Mane

• The viewing angle may be reduced due to layer depth
• There are no deep blacks so the contrast is not the best either
• Backlight leakage can be a problem
• It is not possible to increase the resolution much due to the physical limitation of the transistor size
• Possible temporary "image retention" problem (similar to Burn-in)
• There are no energy savings because the backlight is always on regardless of whether the pixels are off or not

Gary Sims explained in more detail for Androidauthority, so watch the video if you want: