OLED: the Next Thing in Monitors - Types of OLED
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There are going to be many OLED types that will be produced. Each will be made slightly differently. There will be the traditional active and passive monitors, and also some new forms which can change the way we view electronic screens.
The first OLED displays that will hit the market will be Passive-matrix. The first LCD screens were passive, and OLED will follow suit. They are fairly simple structures. They will be more expensive, and consume a lot more power than other types of OLEDs. They will be found in smaller devices with screens smaller than three inches, like MP3 players and cell phones. Passive-matrix is made up of a matrix of electrically-conducting rows and columns making pixels. Between the rows and the columns are the organic layers. On the other side is the substrate, the material which gives the electricity. The more current applied, the brighter the display.
What is going to be in most displays is Active-matrix. They will consume a lot less power than passive matrix. Active-matrix is like passive, but instead of rows and columns, there is a TFT back plate. This will control the brightness of each pixel. There will be two TFT arrays per pixel: one to start and stop the charging of the capacitor, and one to provide a constant electrical current to the pixel. This means that there will be a constant current at all times, so the overall electricity needed to light the display is considerably less than that of passive matrix.
Those are the traditional forms of screens we see nowadays. With OLED we will see new forms of screens, many that have only been seen before in movies. We will soon have the ability to see through our screens and bend them into any shape we want.
Remember the “Lost in Space” movie (not the series)? In the opening seconds they are battling in space on space fighters. What is remarkable is that the screen is see through and mounted on the cockpit window. The pilot can see the computer screen and what’s happening on the outside at the same time.
Believe it or not, this technology is right around the corner. The screen with emit in both the top and bottom directions. It will be 70 percent to 85 percent transparent, roughly equivalent to a piece of glass. Active-matrix has an opaque substrate, so it is top emitting only. For transparent OLEDs, the substrate is transparent, so it emits the screen both on the top and bottom.
Transparent OLEDs will be just like the active matrix. The first use that popped into my head when I read about these was the wearable computer. I have seen a few prototypes of wearable computers, but none of them will take off until the screens become transparent. The computer aspect is set; the computers are small enough to wear. Once these transparent screens become available, look for a boom in the wearable PC industry. If you think talking on the cell phone while driving is bad, imagine using a computer while driving.
The other new type of display will be flexible, meaning that you can bend the displays. Other forms of OLEDs will be thinner than current LCDs, but flexible OLEDs are going to be a lot thinner than even normal OLEDs. This will be great for mobile devices like cell phones and notebooks. They will take advantage of the thinness rather than the flexibility of the display.
The durability of this type of display will be much better than other forms of OLED displays. The problem with LCDs is that they aren’t too durable. Even a moderate amount of force can ruin a display. Flexible OLED displays will be more impact resistant and less breakable. You have heard of "rolling out a product" before, but these will literally be rolled out! They will be manufactured using a process called roll-to-roll (R2R). This is a very low cost way to produce OLEDs.
The U.S. government is helping to develop this type of display for the soldiers in the field. Flexable displays can be mounted onto helmet face shields for a "heads up” display. Alongside military displays, there are other uses for flexible displays, such as on automobile instrument panels.
Next: Even brighter displays >>
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