Traditional tube displays (CRT, Cathode Ray Tube) have given way in recent years to a new batch of flat panel displays based on plasma and LCD (Liquid Crystal Display), and has opened the way to OLED technology. Next, the different technologies are analyzed and a comparative table of advantages and disadvantages is proposed.
CRT Cathode ray tube screens are very deep and heavy due to the inclusion of the tube that allows, by applying a certain electrical voltage, to direct the electrons to the right place on the screen, coated with phosphor. They are the ones that provide higher image quality, in terms of contrast, brightness and definition. Size, however, is limited to 32 inches.
Plasma
The operation of a plasma screen brings you substantially closer to tube technology: light panels divided into cells contain a mixture of noble gases (neon and xenon) that turns into plasma after exciting them with an electrical signal. A phosphorescent substance - which is not phosphorous - then emits the necessary light.
An important parameter to check 5.7 inch tft lcd module for digital technologies is the contrast ratio, the ratio between the darkest and brightest values that the screen can reproduce at the same time.
This type of screen has a high contrast ratio, since it allows showing a true black: since the plasma is divided into independent cells, each one can theoretically be turned off and obtain a perfect black. It is designed for large screen sizes - above 37 inches - and looks the same from any viewing angle. Viewing still images for a long time on a plasma screen is not recommended, so it is not appropriate to use it as a computer monitor.
LCD
Summarizing the operation of a 7 inch display LCD screen, you could indicate that the liquid crystal pixel grid is in front of a light source, so that after the application of an electric current, certain polarizing filters allow more or less light to pass through. This implies that an absolute black like that of plasma cannot be achieved and the contrast ratio will be significantly lower, although manufacturers are improving these features over time. The brightness of a LCD, on the other hand, is much better. Screen sizes have traditionally been smaller than in plasma, although the differences are getting smaller between one technology and another.
A big problem associated with the LCD is the horizontal and vertical viewing angle that it allows: if the limit angle is exceeded, the images will be degraded substantially. Also, unlike phosphorus, the LCD requires certain on and off time commonly called the response time.
The term TFT is frequently used in computer monitors to refer to TFT LCD displays, a type of LCD that uses TFT transistors to reduce power consumption.
OLED
It is a recent technology that starts from traditional LEDs (light emitting diodes) but with an organic emitting layer, which has a much lower consumption and cost. Theoretically they can be adapted to a flexible material and provide very varied screen sizes, from the small screens of 2” from an MP3 player to very large sizes.