There are many unfamiliar terms in the description of smartphones. This material will subsequently be integrated into articles about new smartphones that come out at the end of the month. The text will be supplemented. Please write in the comments, a description and clarification of what concepts you consider important to add. Perhaps you know everything, but you heard how your friends do not understand why, for example, an accelerometer is needed or what some parameter is responsible for. The first part will focus on screen technology.
- Screen types
- Screen characteristics
- Color gamuts
- Smartphone screen refresh rate
Screens have many characteristics. This is a production technology, screen resolution, dot density, indicated in ppi, and various types of color gamut are also often found.
LCD is a liquid crystal display with a backlight under the 'liquid crystal'. LCD screens are common because the technology is familiar and cheap to manufacture. And since they are fully illuminated from below, they show themselves perfectly when working in the open sun. But due to the fact that the screen requires a backlight, such screens may have less clear color reproduction compared to screens that do not require a backlight (OLED).
TFT LCD – Thin Film Transistor (thin film of transistors) is a version LCD in which a transistor and a capacitor are attached to each pixel of the screen. This increases the contrast. But such screens consume more energy, they have worse viewing angles and worse color rendering. If things are so bad, why are they being used? They are cheaper to manufacture than regular ones LCD.
IPS LCD – In-Plane Switching is an advanced version of TFT LCD. IPS screens have two transistors attached to each pixel and a more powerful backlight. These screens have excellent viewing angles, good color rendering, but they consume more power than OLED screens. But less than TFT LCD.
LTPS LCD – Low-Temperature PolySilicon – conventional LCD screen uses amorphous silicon as 'liquid crystals'. Amorphous silicon is good for everyone, but it imposes a limitation on the screen resolution and gets too hot. This option is good for screens with pixel density less than 300 ppi, that is, the resolution Full HD or less.
Polycrystalline silicon, or LTPS, aims to solve these problems. In this form of silicon, electrons run faster, which implies better screen refresh rates and also allows for smaller transistors. This means that such a screen consumes less energy, heats up less and supports a resolution higher than FullHD, since thanks to smaller transistors they can be compacted.
By the way, the screen itself is thinner than the usual one LCD. But in production, LTPS LCD costs about 15% more. However, now it is the most promising technology, since the resolution of smartphone screens is constantly increasing.
IGZO LCD – is perceived as the next stage of development LCD screens after LTPS. In this technology, you can make transistors even smaller, that is, increase their density and obtain an even higher screen resolution. And, of course, the smaller the transistors, the less power they consume, that is, IGZO LCD screens are even more economical. Sharp, which is the main promoter of the technology, already has options for screens with a resolution of 8K and a pixel density of 2,700 ppi or more. This allows for precise color and responsiveness. Sharp says its top-end screens are paper-like when you write on them with a stylus.
Retina is a marketing term from the company Apple. Retina display means a high pixel density per inch – over 300 ppi.
Triluminos display – and this is already a marketing term from Sony, which believes that it has invented a cure for all the 'sores' LCD of displays. Basically it's LCD on quantum dots (Samsung has similar technology in QLED TVs). In simplified language, they took LCD a panel and inserted microscopic (quantum) particles into it, significantly improving color rendition and brightness
OLED, P – OLED, AMOLED, Super AMOLED
OLED is an organic light emitting diode, i.e. organic light emitting diode. There are millions of such diodes, and each one burns with its own color – green, blue and red. They light up in combination, thus forming the desired color.
The main difference from LCD is that each pixel conveys color, brightness and works individually, that is, it can be turned on or off. Due to this, such screens have a higher contrast. The merits of OLED include the fact that they have excellent brightness and color rendering and are much more responsive than LCD. The disadvantages include the fact that such screens are less durable (but, of course, for 3-5 years of using a smartphone, you will not encounter this). And also such screens are terribly afraid of water. Usually manufacturers cover them with protective glass, but still.
AMOLED is an Active Matrix Organic Light-Emitting Diode, i.e. an active matrix organic light-emitting diode. Roughly speaking, AMOLED the screen can be called TFT OLED, since the idea is the same. A transistor and a capacitor are attached to each pixel. AMOLED technology needed for larger screens. For example, 10 inches or more. In fact, the size can be anything.
PM – OLED – this is Passive Matrix Organic Light-Emitting Diode – a passive matrix differs from an active one in that it supplies voltage to a number of diodes at once, and not individually to each one. This is worse for picture quality, but cheaper to produce. Typically used for screens up to 3 inches. Accordingly, it is almost impossible to run into technology now.
P – OLED – Plastic Organic Light-Emitting Diode – here we are talking about the screen substrate (not to be confused with PM – OLED). The first OLED screens used a glass backing. But over time, there was a desire to make screens that are more interesting in shape, and then the glass was replaced with plastic. For example, thanks to this, Samsung was able to make its curved screens. By the way, AMOLED screens can be called P – OLED, but Samsung prefers its own term AMOLED, since the company also has its own know-how regarding brightness, color rendering and other screen parameters. But in general, the average consumer will not notice the difference between AMOLED and P – OLED.
The background in the picture is named Substrate
Super AMOLED is advanced AMOLED as the name suggests. The advancement lies in the fact that Samsung has integrated a touch layer into the screen. Usually the touch layer is superimposed on top of the screen, and here it is inside. Thanks to this, energy consumption has improved, as well as such screens behave better in the sun (increased readability). Usually Super AMOLED is found only in phones of the upper price segments, as it is quite expensive to manufacture.
Dynamic AMOLED is the latest version of Samsung screens. In short, it's Super AMOLED with HDR10 + support. Also, these screens are more gentle on the eyes, as they emit less annoying blue color.
PPI – pixel per inch – density of pixels per inch. The higher this number, the more pixels there are in one inch, and thus the higher the picture quality. Usually, the PPI number is directly related to the screen resolution of the smartphone and its size. The higher the resolution, the higher the PPI. But you can also run into a large screen with a low resolution and, accordingly, a low PPI, then, upon closer examination, the picture will appear grainy. It is believed that the human eye can see individual pixels at 350 ppi, if the density is higher, then it is already indistinguishable.
Screen resolution is essentially the number of pixels that can fit on the screen. The higher the value, the more information can fit. When the resolution is very high, for example, 4K, then manufacturers, in order not to be smaller, simply use larger icons. But with more pixels, the image looks sharper.
Below are the main types of permissions. I would like to point out that the maximum recommended screen sizes are for smartphones that users usually work with close to their eyes. For tablets and monitors, these examples are not suitable, since these screens are usually located at a considerable distance.
- 720p – 1280 x 720 – Mediocre low ppi screens. Always seem grainy.
- 1080p – 1920 x 1080 is a good resolution for a modern smartphone. At 6 inches, the screen has 367 ppi and its pixels are indistinguishable. However, for a 10-inch screen, the resolution Full HD is no longer enough. The pixel density will be 220 ppi, which means the picture will be grainy. Full HD great for screens up to and including 6 inches
- 2K – 2560 x 1440 – excellent resolution for screens up to 8 inches (367 ppi).
- 4K Ultra HD – 3840 x 2160 – is used in top smartphones. Looks good on screens up to 12 inches.
- True 4K – 4096 x 2160 – this is the resolution found in monitors and televisions. There is no such thing in phones.
There are several basic color gamuts, or color spaces. Accordingly, the larger the color gamut, the better the color rendition.
sRGB is the most common format found in smartphones. It covers 33.3% of all visible colors.
DCI-P3 – Digital Cinema Initiatives (DCI) color space used in digital cinemas. Covers most of the natural spectrum. This is a filmmaker association standard. They believe that in this reach, it is best to watch movies. People often watch movies on smartphones, so this color gamut has come here as well. This coverage is 26% greater than sRGB and covers 41.8% of all visible colors.
BT.2020 – This is the color gamut that Sony likes to use in its smartphones and TVs. It covers 57.3% of visible colors and is 72% wider than sRGB
Wide color Gamut – this coverage uses Apple in its iPhone. It covers 77.6% of the visible color spectrum.
Smartphone screen refresh rate
The screen refresh rate is how fast the picture on the screen can change per second. The usual value is 60 Hz. This means that the picture will be rendered 60 times per second. In smartphones, you can find a value of 90 Hz, and Apple, Sharp do 120 Hz. Xiaomi in the smartphone Black Shark 2 has a refresh rate of 240 Hz. Thanks to the high refresh rate, the animation on the screen looks smoother. The video below shows a 60 Hz and 120 Hz screen, the video was shot at 240 frames per second.
Seems to have covered the main features of the screens. In the comments, write that I forgot what to add. What screen options are you asking questions?