All about OLED displays
OLED displays are thin and efficient. They offer extraordinary image quality and can be made transparant, flexible, bendable and even stretchable. OLED is the future of display technologie!
OLED is often confused with other display technologies such as LED and LCD. Below we explain the difference between all technologies. Also read up on how an OLED display works, what OLED technologies are out there and the advantages and disadvantages of OLED.
LCD vs. OLED displays
What is the difference
LCD stands for Liquid Crystal Display. It is equipped with liquid crystals. You can control the crystals by using electrical voltage. A backlight ensures light behind the crystals. The voltage cause the crystals to rotate and light may or may not shine through the display. As a result, an image is displayed.
Most LCD displays are equipped with a LED backlight. An alternative backlight for an LCD is a CCL backlight.
Since LED has so many advantages, this technology is used more often. A LED backlight is brighter, consumes less energy and displays with LED backlighting are thinner. Some LCD displays (like TV’s) are also equipped with LED lights around the edges, or behind the panel. This gives the viewer an extra dimension.
An OLED display is made out of millions of small LED lights (diodes). OLED’s additional “O” stands for organic. Since the diodes can provide light by themselves, OLEDS do not need a backlight. This allows OLEDS to be a lot thinner than the average LCD displays. An additional advantage is that OLED panels are very light.
The layer images will clearly show the differences between an LCD display and an OLED display.
How does an OLED display work?
As mentioned earlier, an OLED display is equipped with a million small LED lights (diodes). These little lights contain an organic component that emits light, when there is an electrical voltage. Because the lights already illuminate the display, no backlight is required to illuminate the pixels.
The pixels of an OLED can be completely turned on or off. Because of this, OLED displays are completely black when turned off. OLEDS can therefore produce very high contrasts and the images are very bright and sharp. Also, the colors and the response time of the display are very fast due to the OLED technology. Because OLEDS do not require backlight, the displays are very thin. There is an example of an LG OLED display with a thickness of only 1 mm.
The image of an OLED is beautiful. However, OLEDS also have disadvantages. Because OLED screens contain organic material, their lifespan is shorter than LCD displays. Additionally, many OLED displays get burn-ins after showing the same image for a long time. After a burn-in, the image stays on the screen even after showing another image.
OLED display technologies
There are two types of OLED display technologies: passive matrix OLED (PMOLED) and active matrix OLED (AMOLED). The difference between these two is the interface. This can be passive or active.
A PMOLED display has a simple interface which controls each row of pixels individually. PMOLED electronics do not have storage capabilities. This is why the pixels are turned off most of the time. To compensate for this, PMOLED displays need more power for brighter pixels.
For example: a display has 10 rows. The row that’s turned on has to be 10x times brighter compared to the other rows.
PMOLED displays are easy and cheap to produce. However, they are not very efficient. The OLED material suffers from the high voltage, lowering the displays’ lifetime. These displays are often small (up to 3 inch) and used to display characters or small icons in for example MP3 players.
An AMOLED display is controled by a TFT with storage capabilities. This keeps pixels in a set state (either on or off). That is why AMOLED displays can be made in larger sizes. There are no restrictions when it comes to size and resolution.
Currently, there are two types of AMOLED technologies: RGB OLED from Samsung and WOLED from LG.
The RGB OLED technology was designed by Samsung. RGB OLED stands for Red Green Blue Organic Light Emitting Diode.
Each pixel of an RGB OLED display consists of three subpixels. One red, one green and one blue. The color that appears in the image is determined by the intensity of the light emitting of the subpixels. If the pixels do not emit light, the image is black. In addition, the image is white when the light intensity is maximal. The RGB OLED technology ensures beautiful bright colors. But the viewing angles are slightly less than the WOLEDS.
LG uses the WOLED (White OLED) or WRGB (White RED Green Blue) technology for producing OLED displays. This adds a fourth white subpixel to the RGB subpixels. The RGB pixels have a filter, but the whites have not.
According to LG, the colors of the displays are even brighter and therefore the viewing experience becomes more realistic. Certainly for TV’s, this is something that people like. This technology has the advantage of having intense colors. In addition, the viewing angles are very wide.