Optical Light Emitting Diodes

Optical Light Emitting Diodes

Optical Light Emitting Diodes

Yash Pareek

B. tech scholar

Department of Electronics and Communication Vivekananda Institute of Technology Jagatpura, Jaipur, Rajasthan

Abstract:- Basically OLED is a subset of LED (light emitting diode) with some changes. It is a different version of solid state lighting source. It is typically formed in a layer or sheet made up of organic thin layers placed between an anode and cathode on an underlying substance or layer called substrate. The amount of layers depends upon the desired light output. This technology have an emerging future for new technologies because OLED(s) are light in weight, comparatively thinner, and response time is better. New technologies like sophisticated organic layer is applicable to the devices. It exhibited good durability like storage stability, that is dominating factor in practical use. Light sources which are eco friendly and comparatively low power consuming are trending. Each OLED provides its own illumination which greatly enhances the viewing experience. Research efforts are still going into this field. OLED promises a bright future in the field of light source as it is low power consuming, and also being organic, no harm to the environment and human. This paper will review the Organic light emitting diode(s), advantages and the disadvantages and the problems occurs in its implementation.

IMPORTANT TERMS: LED- Light Emitting diode is a type of diode which emits light while taking the energy OLED- Organic light emitting diodes is an advanced form of LED LCD- Liquid Crystal Display

INTRODUCTION:

An organic light-emitting diode (OLED) is actually a type of LED, which consist of emissive electroluminescent layer, it is a film of the organic compound that emits the light in response to an electric charge or current. Organic light- emitting diodes (OLEDs) are used to create the digital displays in the devices like televisions, computer screens, portable systems screens, like smartphones screen, gaming consoles, etc. A major part of researcher is in the development of white organic light emitting diode devices to use in a solid – state lighting applications.Organic light emitting diode displays devices use organic films, layered between the two charged electrodes. In which one is metallic and the other one is a transparent anode, mostly which is a glass. OLED can be used either by passive matrix or by active matrix addressing schemes.OLED works without a backlight; so, it keeps a potential to display the deep black levels, and it can be thinner as well as lighter then a LCD.

Prof. Sanjiv Kumar

Head of the department Department of Electronics and Communication

Vivekananda Institute of Technology Jagatpura, Jaipur, Rajasthan

Types of OLEDS

Basically there are six (6) types of organic light emitting diodes. Each of them is designed for a different purpose. Types are mentioned below:

1. Passive Matrix Organic Light Emitting Diodes (PMOLEDs): they have a strip of cathode, organic layering and an anode strip. Anode and cathodes stripes are perpendicularly placed at each other. A current is supplied to the stripes to determine the pixels that whether it is on or off. And also the amount of this current affects the brightness. Comparatively its production is much easier.

2. Active matrix organic light emitting diodes (AMOLEDs): Instead of stripes it consists of full layer cathode, anode, and organic molecules. And there is a (TFT) Thin Film Transistor which makes a matrix on anode. This sets pixels on or off to make an image. It consumes less power as compared to PMOLED because TFT arrayAMOLED are mostly preferred in the large displays. Large tvs, monitors, etc.

3. Top emitting OLEDs: They have reflective or opaque substrates. They consist of most active matrix design as it fits best. This is commonly used in smart cards.

4. Foldable OLEDs: plastic or very flexible metallic foils are used on substrate of foldable organic light emitting diodes. They are very strong and very light too.It is used in smartphones. Other usages can be GPS devices and integrated computer chips.

5. White organic light emitting diodes: in this type the emitted light is white. It is more energy efficient and more uniform then those regular fluorescent. It has true colour characteristics. So it can be replaced with the traditional light.

6. Transparent OLED: it consists of transparent components only like anode, cathode, and substrate. it allows the light passing in both the directions when it is switched on. It can either be active matrix or be passive matrix.

CONCLUSION:

We have seen a very huge progress in this field in all terms. Emission, charge transportation and charge injection are the three main processes by which the effectiveness is governed. It has achieved a long operational stability. Necessary targets for application in displays is matched by the OLEDs. Many researches are going on in this field and this field also keeps the potential to change the way we see the screens. We hope it will cover up the markets as soon as possible as it is cheaper,

more productive, harmless and compatible as well. Maybe we can see the newspapers in the OLED displays in the morning outside our doors, but for that we need to give a hand too.

REFERENCES:

[1]. https://www.researchgate.net/profile/Navaneetha_C_M/publication/30 8332988_Organic_Light_Emitting_Diodes_OLED/links/57e1136408a e9834b4e7cd26/Organic-Light-Emitting-Diodes-OLED.pdf

[2]. OLED Fabrication for Use in Display Systems / Chris Summit/06.12.2006

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[5]. Introduction and basic OLED Information, Available Online at: http://www.oledinfo.com/introduction