Transparent OLED Panel Technology

Mobile phone with TOLED panel.  
(Picture from: http://blogs.msdn.com/)

Today, mobile phone manufacturers began introducing mobile phones that use transparent OLED panels. Transparent OLED panel on mobile phone, measuring 2.4 inches.

OLED (organic light emitting diode) panel are devices that emit light themselves (self-luminous) and use a thin layer of organic light-producing material. OLED panel technology was first developed by researchers at the Eastman Kodak Co. Rochester, New York.

OLED panel consists of OLED cells. Tues OLED consists of electroluminesens organic materials that emit light when stimulated by electricity. Electroluminesens generally refers to the events of light emission by a material in response to the voltage applied to the material.

Samsung’s Transparent OLED Laptop Display. (Picture from: http://gadgetcrave.com/)

Basic OLED cell structure consists of a stack of thin organic layer inserted between a transparent anode and a metallic cathode. The organic layer consists of a layer of injection holes (positive charge carriers), hole transport layer, emisif layer, and an electron transport layer. Each organic layer has a thickness of about 100 nanometers.

When a certain voltage (typically a few volts in small quantities) is given on the OLED cell, positive and negative charges are injected be recombined in a layer emisif. The charge recombination events produce light.

One type of existing OLED panel is transparent OLED panel (TOLED / transparent organic light emitting diode). Transparent OLED development was first claimed by researchers at the Technical University of Braunschweig, Germany. The approach they use to create transparent OLED is to use a TFT (thin film transistor) made of transparent zinc tin oxide layer with a thickness of 100 nm which transmits more than 90 percent of visible light.

TFTs and OLED pixels in a transparent OLED panels are placed next to each other. Due to the size TFT layers are thin, layers can be deposited over a large area with the usual techniques for the manufacture of transparent OLED panel.

Transparent OLED structure.(Picture
from: http://electronics.howstuffworks.com/)

Transparent OLED panel has a component substrate, cathode and a transparent anode. When disabled (off), to 85% remains transparent substrates. When a transparent OLED panel is turned on (on) or electrified, this panel channel light in two directions (up and down). Because of that ability, transparent OLED panels can be used for heads-up panels, bulkhead light (a device that is almost invisible during the day and the light scattered / diffuse at night), lights, light canopy, windshield displays navigation and warning , and architectural glass.

Transparent OLED panels can be made with a passive matrix arrangement (known as PMOLED) and active matrix (known as AMOLED). PMOLED (passive matrix OLED) is a type of OLED which has a structure such as the blades of cathode, organic layers, and the blades of the anode. The blades crossing the anode fitted with blades of cathode. Intersections on the cross between the anode and the cathode is a pixel dots. The resulting number of pixels depends on the amount of electric current that flows from the source / power voltage at the anode and cathode blades that have been determined. The greater the current flow, the brighter the light produced.

PMOLED easy to make, but the power consumption is greater than with other types of OLED. PMOLED most efficiently used to display text and icons and the most suitable for the smaller screen size (diagonal screen size of 2 to 3 inches) as the panel on the HP and MP3 player.

The AMOLED (active matrix OLED) is a type of OLED which has a structure layer of cathode, organic molecules and anode which are shaped overlay. Overlay layer anode on an array of TFT AMOLED which form a matrix. Composition of TFT itself is nothing but a series that determines the selection of pixels for the formation of an image.

The electric power consumed by AMOLED smaller than the electrical power consumed PMOLED. This is because the presence of the circuit in the form of TFT devices that require less power than the external circuit used PMOLED. Therefore, more efficient AMOLED used for large panels such as computer monitors, large screen television, and electronic billboards. *** [DEDE NURROSYID | PIKIRAN RAKYAT 30082012]

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