Chapter 2. Principle of action

Report

«OLED-Display»

Prepared by:

Deinea Oleksandr

group RV-11

Kyiv 2014

Plan

Introduction………………………………………………………………………………...3

1. Chapter 1. OLED-Display………………………….……………………………………4

2. Chapter 2. Principle of action……………………...…………………………………….5

3. Chapter 3. The history……………………...……………………………………………6

4. Chapter 4. Types of OLED-displays..…………………………………………………...7

4.1. PMOLED……………………………..…………………………………………7

4.2. AMOLED……………….………………………………………………………7

5. Chapter 5. Other types of OLED displays……………………………………………….8

5.1. TOLED.…………………………………………………………………………8

5.2. FOLED (Flexible OLED)…………………………..…………………………..8

6. Chapter 6. Super AMOLED technology and a new generation………………………….9

6.1. Staked OLED………………………………………………………………..…..9

7. Chapter 7. Advantages compared to LCD-display…...…………………………………11

Summary……………………….…………………………………………………………..12

Bibliography……………………………………………………………………………….13

Introduction

I chose this topic for my report because OLED displays are those displays are gaining popularity and will be used in the future everywhere. But, even if now we have not yet fully explored the OLED technology, but I believe that it is the foundation of the future of monitors and screens.

Chapter 1. OLED-Display

Physical organic electroluminescent display represents a solid device, consisting of a few very thin organic films made ​​between two conductors. Submission to the conductors of a small voltage (about 2.8 volts) and causes the display to emit light. The basis of the OLED-matrix are polymers, their continual improvement largely improves the display and development of manufacturing technologies matrix.

Currently, driven primarily two technologies, which showed the highest efficiency. They differ used organic materials are polymers (PLED) and macromolecule (sm-OLED). Consider them in detail we will not, because the phone's user is not critical, and very rarely in the manufacturer specifications phone with the technical nuances of manufacturing the display.

Different OLED-displays decent mechanical strength, and even flexibility. However, the use of flexible substrates already liberated in a separate direction FOLED. And, finally, in contrast to the existing TFT and STN displays, OLED-displays consume significantly less power. By analogy with the other displays are also possible to use passive or active matrix.

Most often, OLED-displays are used as external (or auxiliary) displays, as do the main display of the phone based on OLED-technology, at least, expensive. For the same reason, these displays are usually limited to 256 colors reproduction. For example, a display with a resolution of 94 x 94 pixels is used in LG G7030, a Samsung SGH-E700 resolution slightly smaller (96 x 64 pixels). In general, these displays look very good, providing a bright and readable picture, but, unfortunately, the sun consider anything on this display possible.

Chapter 2. Principle of action

To create Organic Light Emitting Diode (OLED) are used thin-film multilayer structures consisting of layers of several polymers. When applying to the anode positive relation to the cathode voltage, the flow of electrons flowing through the device from cathode to anode. Thus the cathode gives electrons to the emission layer and the anode takes electrons from the conductive layer or in other words, the anode gives a hole in the conductive layer. Emissive layer has a negative charge and the conductive layer is positive. By electrostatic forces electrons and holes move towards each other and recombine at the meeting. This happens closer to the emissive layer, because in organic semiconductors holes have greater mobility than electrons. There is a decrease in the recombination of the electron energy, which is accompanied by the emission (emission) of electromagnetic radiation in the visible light region. Therefore the layer is called emissive.

Scheme of a two-layer OLED-panel:

1. The cathode (-),

2. Emissive layer,

3. Emitted radiation,

4. Conductive layer,

5. The anode (+).

The device does not work when applied to the anode, the negative relation to the cathode voltage. In this case, the holes move to the anode, and the electrons in the opposite direction to the cathode, and recombination occurs. As an anode material commonly used indium oxide doped with tin. It is transparent to visible light and has a high work function which promotes injection of holes in the polymer layer. For the manufacture of cathode often use metals such as aluminum and calcium, as they have a low work function, promotes injection of electrons into the polymer layer.

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