Chances are, the screen that you’re reading this article on is either an LED, OLED, or an LCD display. These are just three of the many display types out there in the wild. On the surface, they all seem the same. But deep down, they couldn’t be more different.
So, when it comes to OLED vs. LCD—or OLED vs. LED—what are the differences? Here’s a look at these three display technologies, what makes them different, and which one is the best.
LCD stands for “liquid crystal display”. The early roots of LCD displays stretch back to 1888 when German scientist, Friedrich Reinitzer, discovered an odd substance. It was a liquid that had the molecular structure of a solid. It was later named “liquid crystal.” After decades of study, someone eventually saw the potential for this strange substance to be used for displays.
The first LCD displays to be used on consumer devices were on digital clocks back in 1968. The technology developed over the following years, being put into numerous other devices.
LCD technology has now grown exponentially and is a mainstay in consumer technology.
How Do LCD Displays Work?
LCD display panels are divided into layers. The backmost layer is a light source. This is a translucent sheet that disperses light from bulbs at the bottom of the display.
The light travels through a vertical polarization filter. Only light vibrating on the vertical plane can pass through the filter. The polarized light then passes through a transistor. The transistor is responsible for applying current to the liquid crystal layer.
The liquid crystal layer is next. The current that’s generated by the transistor causes the molecules in the liquid crystal to twist 90 degrees. When the molecules are twisted, the polarized light that passes through gets rotated 90 degrees, now vibrating on the horizontal plain.
Next, the light passes through a transparent electrode. The electrode is necessary for the current to pass through the liquid crystal. After the electrode, there’s a horizontal polarization filter. Since the light is vibrating on the horizontal plain, it can pass through unphased.
After the filter, the light gets its color by passing through the red, blue, and green filters of the sub-pixels. From there, the light exits the display and creates the image that the viewer sees.
OLED stands for “organic light emitting diode.” During the 1970s, scientists were experimented with organic materials that can emit light. In 1987, scientists at Eastman Kodak developed an OLED display that consumed a low amount of energy. And in 2007, Sony unveiled the world’s first OLED television: the Sony XEL-1.
Like LCD devices, OLEDs have grown in popularity—especially over the course of the 2010s and early 2020s.
How OLEDs Work
The light from an LED is emitted from an electrical current going through an organic compound. That organic compound is sandwiched between a positively charged anode and a negatively charged cathode. The cathode is rich in electrons, and the anode is rich in electron “holes”. Electron holes are areas in an atom where there is no electron.
When a voltage is sent through the layers, the electrons and holes migrate toward one another. The holes travel from the anode and they cross the conductive layer, a layer of organic plastic compound that’s good at transporting holes.
On the other side of the OLED, the electrons flow from the cathode. The electrons then flow to the emissive layer, where they meet the holes. Since the electrons are sent through a voltage, they are “excited”, meaning that they have an excess of energy.
When they meet the electron holes, they have to lose that excess energy in order to relax to the ground state for that atom. They release that energy in the form of photos (light particles). From there, the light travels through the red, blue, and green sub-pixels, just like with an LCD display.
LED displays are virtually indistinguishable from LCD displays. The only difference is in how the two types of displays get their light. Instead of using a translucent sheet, LED displays use individually LEDs. There are three primary arrangements of LEDs in the displays.
Full array LED displays have the LEDs arranged evenly throughout the display. This is the preferred arrangement on higher-end TVs. There are a lot of LEDs behind the panel, which means that local dimming is possible.
The direct-lit arrangement can appear to be similar to full array, but there are some differences. With the direct-lit arrangement, the LEDs are also dispersed evenly throughout the panel, but there are far less of them. Because of this, direct-lit displays can not do local dimming. This arrangement is present on lower-end devices.
Because LCD and LED are so closely related, they are often compared to one another.
Comparing the Three Technologies
Each technology has its own benefits and drawbacks. So, how do they stack up against each other?
Let’s take a look.
A display is usually judged by its ability to create vibrant colors. This is an area where OLEDs come out on top. Compared to OLED displays, LCD displays often appear washed out and not as saturated. This is why OLED displays are becoming more popular in the smartphone market.
OLED displays can also produce images with higher contrast than the other two technologies. Since all of the OLEDs on the panel can be turned on and off individually, darker areas of the display can go as dark as they need to.
Full array LED displays come in right behind OLED displays because, like in the case of OLED displays, the LEDs in an LED display can be controlled individually. Full array LED displays use a method called “local dimming”, a technique of shutting off LEDs completely in areas that are darker.
LCD displays come in last place because in order for any pixels to be visible, the entire back panel has to be lit. This means that completely black areas are impossible to achieve.
In terms of price, LCD displays are typically cheaper. High definition LCD displays can run you no more than a few hundred dollars. Since LED displays offer better contrast over LCD, you can expect there to be an added price premium.
OLED displays are, on average, more expensive than the other two technologies.
4. Power Consumption
When it comes to power consumption, OLED scores a win. Since the OLEDs are powered individually, the display only gives power to the ones that need it. Pixels can be turn off completely when there are blacks in the picture.
Full array LED displays come in second place because of the local dimming functionality. Certain LEDs can be completely turned off when the scene calls for blacks. Even though they have this feature, more energy is consumed per LED because the light has to pass through all of the layers of the LCD before reaching the viewers’ eyes.
LCDs are the least power efficient. Regardless of the presence of blacks in the scene, the entire panel needs to be lit. This means that the light source is shining at 100% the entire time.
LCD vs. LED vs. OLED: It All Depends On Your Needs
Each display technology has its benefits and its drawbacks. LCD displays are for people who want to save more money, while LED displays are for people who would like to spend more for a bit more contrast in their picture. You’ll spend more on the TV, but it will have a less significant impact on your electricity bill.
OLED displays are for those who want the best of all worlds. They produce the best contrast with the most vivid colors. You will be paying the most for the actual device, but the more power efficient display technology will help even out some of that cost.
Either way you slice it, if you choose the right manufacturer, you will have a great viewing experience no matter what the technology.
Author: Arthur Brown
Source: Arthur Brown.” OLED vs. LED vs. LCD Displays: What’s the Difference?”. Retrieved From https://www.makeuseof.com/oled-vs-lcd/
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