LED technology has changed the way we interact with our world and devices. From the small indicator lights on our electronic devices to the massive displays in public spaces, LED technology has become ubiquitous in our daily lives. The pros of this technology such as high energy efficiency, increased brightness, and longevity of LED displays make a practical choice for a wide range of applications. This is why they are found in almost every device we use, ranging from cars, monitors, smart devices, billboards, and televisions So, if you are curious about what LED displays are, the types of LED displays available, and how they work, then this post is for you. Because in this post, we will take you through everything you need to know about LEDs.
So, without wasting any more of your time, let's dive right into it.
LED stands for Light Emitting Diode, and in its basic form, it is a semiconductor material that glows or emits light whenever light passes through--just as the first two words in its name suggest. The third word, "diode" in the acronym LED means, allows current to flow in one direction, and this feature is what makes LED highly efficient, long-lasting, and as a result, a preferred choice for displays.
Just as the name implies, text display LEDs consist of a primary screen which consists of an array of LEDs and they are designed to display only text and alphanumeric information. It is important to note that these types of LEDs displayed are preprogrammed to display certain kinds of text. For example, the Welcome LED board you see in restaurants or the "We're Open"/"We are closed" LED boards you see in various stores are typical examples.
You will notice that the LED is engineered to take the shape of the texts they display; hence, they are fixed, and cannot be changed.
This type of LED display is often more sophisticated than text display, such that they feature two LED screens and these screens work together to display images. These types of LEDs are capable of displaying text. The images and text displayed in an image display LED are stationary. You will often see these types of LEDs on a typicalsimple billboard.
These are the type of LEDs you will find on modern billboard ads such as those in Times Square. And these types of LEDs are designed by featuring numerous high-pixel LEDs that display moving images with a higher resolution.
The only difference between a digital display and a text display LED is that digital display LEDs screens are only designed to show numeric values. They illuminate red or glowing orange light and this is because they are made of a seven-segment digital Nixie tube. This type of Nixie tube uses 7 segments to create all the digits needed to be displayed. You will often see these types of LEDs in banks displaying currency data or in digital clocks.
This type of LED is capable of displaying text and image data simultaneously. They consist of matrices of LEDs that are arranged in a series of rows and work together to display both text and images. It is capable of displaying text in motion, but the pictures displayed tend to be still. You will often notice that these kinds of LEDs are used to display a variety of text that tend to be in motion. These types of LEDs are used in airports to display gate information and flight details; they are used in concerts to communicate information to attendees, for example, the name of the artist performing; they are used in stadiums to display statistics, and even in some billboards.
The difference between a LED lattice image text display and a text display LED is that an LED lattice image text display can display dynamic text while a text display LED only displays static text.
Just as the names suggest an LED display with edge-lit technology features LED lights placed at the periphery of the display pointing towards the center of the display. These LED strips are either placed only on the sides or below or all around the LCD screen. The way these LED technology works is simple; what happens is that the light from the LED strips at the edges of the device shines into a light guide, this light guide then directs the light into a diffuser, the diffuser finally spreads the light evenly and uniformly across the screen to produce a desired image with no bright spots.
This LED technology has been in existence for ages, and it is now found in most budget-friendly LED displays.
Direct-lit LED is an upgrade of the ELED technology. With the direct-lit, the LEDs are placed behind an LCD screen to illuminate the screen. The LEDs are positioned horizontally in a grid pattern from end to end of the screen. This arrangement of LEDs ensures that light is shined evenly across the screen. However, it is worth noting that the light is further passed through a diffuser which also spreads the light uniformly across the screen.
Due to the numerous LEDs and uniform arrangement of LEDs used in this technology, they tend to produce brighter images and provide more contrast than ELED displays. And even though displays that feature this type of technology are affordable, we will like to highlight that they tend to be more expensive than ELED displays.
The next type of LED technology used in displays is a full array. Full-array LEDs are another type of backlit LED-- just like direct-lit-- however, the difference for this is that more LEDs are used compared to the direct-lit technology, and these LEDs cover the entire back of the display, providing better brightness and color contrast. However, one feature that sets full arrays apart is that the LEDs used are grouped into various zones which can be controlled individually to provide a robust contrast control that automatically adjusts the light output of specific areas of the screen, creating deeper blacks and brighter highlights-- this is known as local dimming.
RGB stands for Red-Green-Blue, and this type of LED is often used to produce aesthetic and colorful illuminations. If you are into gaming or decorations, you have probably seen an RGB LED.
The way this LED works is simple, each RGB LED has a red, green, and blue component attached to the LED. So, depending on the color to be displayed, the current flowing through either of the red, green, or blue components is varied, as a result, each color component is either made to be dimmer or brighter. For example, to produce a purple color, the current flowing through the red and blue components is heightened, while the current flowing through the green component is lessened, as a result, the purple color is achieved.
So, the ability to control the illuminance of either of the three color components of the RGB LED is the reason why this type of LED can produce various and almost all colors.
If you might have noticed, the first three technologies we addressed in this section consist of a display (LCD) and an LED, and what the LED does is produce light for the LCD. Well, OLEDs take a different path such that with OLEDs, the display itself produces its light when current passes through; therefore, there is no requirement for backlighting. Essentially, how this works is that the display such as a Glass TFT backplane has certain organic compounds such as Polyfluorene, or Triphenylamine built in them, and when current passes through, they emit light.
Due to the absence of a backlight, OLEDs tend to be thinner than the first three types displayed and highlighted in this section. Not only that, but OLEDs have an infinite contrast ratio and this is because the brightness of each pixel can be controlled independently. Besides that OLEDs are known to be more color accurate, and have a faster response time with an unlimited viewing angle than their predecessors.
QLED is a typical LCD-LED screen with quantum dots technology. So, previous LCD-LED displays consist of a blue LED backlight, this blue light is then filtered through a layer consisting of phosphorus gas, turning the blue light into white. This white light then passes through various RGB pixels to produce colored images on the screen. Well, the issue with this process was that the resulting image had the colors: red, white, and black being pale and affecting the overall image quality.
Well, to solve this problem, developers brought about quantum dots, and essentially, with a QLED, the phosphorus filter screen is replaced with red-and green quantum dots. These quantum dots do not act as filters but rather they emit their light, and when the blue light from the backlight LED passes through them, the mixture produces pure white light, which is then sent to the subpixels to produce images. Note a combination of red green and blue produces white, which is why it happens.
This process causes QLEDs to produce more vibrant colors with great contrast and less operating energy consumption.
The idea of a mini-LED is built off that of a QLED. Essentially, it features the same technology as a QLED, with the only difference being that the LEDs on the backlight are much smaller and numerous; hence the name. Due to the numerous LEDs, it can be further sectioned into more zones providing more control of the black levels and more contrast compared to a QLED.
The final type of LED on our list is the micro-LED and this technology is a variation and an upgrade of the OLED. Unlike OLED which uses organic materials to produce its light, micro-LEDs use inorganic materials such as Gallium Nitride to produce its light. Due to the use of inorganic materials, this type of display tends to produce brighter images with less