The display has seriously evolved over the past few decades — gone are the days when the only display we had was the humble TV. Nowadays we have a display in our pocket, a few at home, on our desk at work, and even on our wrist.
While displays have become more common, the technology behind them has also changed a lot. In fact, there are quite a few types of display out there. Here are the most common types of display and what sets them apart from the others.
The classic CRT display is perhaps the oldest of the bunch, and the one that is used the least at this point in time. The CRT display, or cathode ray tube, is basically built up of ray guns that fire beams of electrons inside the screen. The screen is then coated with tiny dots of color, with each beam only taking a fraction of a second to hit the screen. Three guns are used inside CRT screens — a red, green, and a blue one. When combined, this allows the screen to display all kinds of colors, with other colors being generated with a combination of the three colors.
Little known fact — the LCD display is a type of LED display, but it works slightly differently. The Liquid Crystal Display has been used for decades now, and actually doesn’t emit any light of their own. Instead, LCD displays require a backlight — normally a CCFL backlight — to illuminate the screen. A light diffuser is placed in between the backlight and the screen to help make the light a little more uniform across the screen.
In front of the backlight, there are millions of pixels, each of which has sub-pixels that are either red, blue, or green. Each of those pixels has a glass filter behind it, and another in front of it at 90 degrees. In its normal state, the pixels look dark, however in between the two glass filters is a tiny liquid crystal that can be turned on or off (twisted or untwisted) depending on the image. The pixel is then lit up, and the color filters turn that white light into colored pinpricks of light that you see. When the white light passes through a pixel with red and green subpixels shut off, the light will appear blue. When all three subpixels are open, the light will combine to appear white. By mixing the different colors with varying amounts, the display can create different colors of light that create an image.
Because they use a dedicated backlight, LCD displays are generally brighter than other types of display.
LED displays actually work exactly the same way as LCD displays, however instead of using a CCFL backlight, they use an LED backlight. LED backlights are far more energy efficient and smaller than CCFL backlights, meaning the television screen can be thinner.
Interestingly enough, marketing divisions made a big fuss over LED displays when they first came out, however really only the backlight is different than LCD displays.
Like LCD displays, the image on a plasma display is made up of an array of red, blue, and green pixels. Each of these pixels can then be switched on or off individually using electrodes, which are both horizontally and vertically mounted in a grid. When a pixel needs to be activated, the two electrodes, both horizontal and vertical, put a voltage across the pixel, causing it to emit an ultraviolet light. That light then shines through a phosphor coating inside of the pixel, which converts the ultraviolet light to visible light, then causing the pixel to light up.
There are a number of advantages to using a Plasma display over other types of display. For example, Plasma displays generally show deeper blacks than other display types. Because they have deeper blacks, Plasma displays also have a higher contrast ratio than other types of displays.
OLED displays are very similar to LED displays apart from one important difference — they’re organic. That’s right, OLED stands for organic light emitting diode. OLED displays take the same idea behind the LED display, but basically flatten things a little. Instead of using LED bulbs , OLED displays use a series of light emitting films, allowing the display to be brighter while still being more energy efficient. Another difference is that while backlights only shine white light in LED displays, in OLED displays, the backlight can also act as a color array, helping produce better picture quality.
As you can see there are plenty of display types out there. LCD displays actually cover the majority of displays being used today, especially if you consider the fact that LED and OLED displays are still technically a type of LCD display. One thing, however, is for sure — we’re likely to see more and more display types pop up over the next few years.