OLED Screen Technology

C O N T E F P R S A I PAST OF OLED APPLICATION WORKING PRINCIPLE OF OLED USED THE MATERIALS PRODUCTION PROCESS OF OLED TYPES OF OLED OTHER DISPLAY TECHNOLOGIES ADVANTAGES AND DISADVANTAGES FUTURE OF OLED APPLICATIONS

CRT TO OLED

Substrate: (clear plastic, glass, foil) - The substrate supports the OLED. Conducting layer: This layer is made of organic plastic molecules that transport "holes" from the anode. One conducting polymer used in OLEDs is polyaniline. Emissive layer: This layer is made of organic plastic molecules (different ones from the conducting layer) that transport electrons from the cathode; this is where light is made. One polymer used in the emissive layer is polyfluorene. Cathode (may or may not be transparent depending on the type of OLED) - The cathode injects electrons when a current flows through the device.

When a voltage is applied to the electrodes the charges start moving in the device under the influence of the electric field. Electrons leave the cathode and holes move from the anode in opposite direction. The recombination of this charges leads to the creation of a photon with a frequency given by the energy gap (E = hν) between the LUMO and HOMO levels of the emitting molecules. Therefore, the electrical power applied to the electrodes is transformed into light.

Charge Transport And Light Generation in OLED's

ANIMATION OF MAKING PHOTON

Active-matrix OLED (AMOLED) AMOLEDs have full layers of cathode, organic molecules and anode, but the anode layer overlays a thin film transistor (TFT) array that forms a matrix. The TFT array itself is the circuitry that determines which pixels get turned on to form an image.

OLEDs Rely on Organic Materilas

Used Materials

Example of Used Materials

Shortly Polymers Structure of OLED

Shortly Small Molecules Structure of OLED

According to the Chemical Structure of Color Diffraction

According to Cemical Structure of Color Diffraction

Shortly Image Formation Displaying is occured with pixels. Pixels are the smallest unit of information that makes up a picture. Each pixel stores color information for your image. It will usually store it in either 3 components, known as RGB (Red, Green, Blue) Pattern of R,G,B Emitting Subpixels

Secret of White Color Exciting work of Prof. Kido 1990 Tb(acac)3 green light(545 nm) 1991 Eu(TTA)3 red light(615 nm) 1995 TPD blue light(410-420 nm)

Preparation of Substrate Deposition of Multi-layer Structure STAGES Preparation of Substrate Deposition of Multi-layer Structure Encapsulation Final Device-Measure

1) Preparation of Substrate i) Patterning in ITO (Indium Tin Oxide)

ii) Cleaning of The Substrate Sonicate in 10% NaOH solution Rinse thoroughly in water Sonicate in fresh 10% NaOH solution Store immersed in water until required N2 blow dry

iii) Spinning on PEDOT:PSS or poly (3,4-ethylenedioxythiophene) poly(styrenesulfonate)

2) Deposition of Multi-layer Structure i) Deposition of Alq3 (Tris-(8-hydroxy-quinoline) aluminum) (Deposit Electron Transport Layer)

Vacuum deposition or vacuum thermal evaporation (VTE) The biggest part of manufacturing OLEDs is applying the organic layers to the substrate. Vacuum deposition or vacuum thermal evaporation (VTE) Organic vapor phase deposition (OVPD) Inkjet printing Spin - Coating

ii) Deposition of LiF/Al (Deposit Cathode)

3) Encapsulation

4) Final Device-Measure

(Passive Matrix OLED)) AMOLED (Active-matrix OLED) PMOLED (Passive Matrix OLED)) Transparent OLEDs Top-emitting OLED OLED Foldable OLED White OLED Flexible Oled

The organic layer is between cathode & anode run perpendicular. The intersections form the pixels.

Easy to make. Use more power. Best for small screens.

PATENTS PMOLED display Inventors : 闫晓剑 Applicant : 四川虹视显示技术有限公司 The Date of file acceptance : 31.12.2010 Release Date : 24.08.2011

Full layers of cathode and anode. Anode over lays a thin film transistor (TFT). Requires less power. Higher refresh rates. Suitable for large screens

AMOLEDs have full layers of cathode, organic molecules and anode, but the anode layer overlays a thin film transistor (TFT) array that forms a matrix.

PATENTS Amoled display card Inventors : Jeong-Hee Cho, Kyeong-Il Jeong, Do-Keun Kim, Dong-Tark Lee Applicant : Kookmin Bank Co., Ltd. The Date of file acceptance : 17.11.2008 Release Date : 30.08.2012

HUD

PATENTS Transparent oled device Inventors : Herbert Lifka, Cristina Tanase, Coen A. Verschuren Applicant : Koninklijke Philips Electronics N.V. The Date of file acceptance : 19.10.2009 Release Date : 06.07.2011

Top-emitting OLEDs have a substrate that is either opaque or reflective. They are best suited to active-matrix design. Manufacturers may use top-emitting OLED displays in smart cards.

PATENTS Encapsulation of top-emitting OLED panels Inventors : Christophe Fery, Gunther Haas Applicant : Thomson Licensing The Date of file acceptance : 17.10.2003 Release Date : 24.07.2013

White OLEDs emit white light that is brighter, more uniform and more energy efficient than that emitted by fluorescent lights. White OLEDs also have the true-color qualities of incandescent lighting.

PATENTS Stacked White OLED Having Separate Red, Green and Blue Sub-elements Inventors : M·斯卢特斯凯, S·福里斯特, 亓向飞 Applicant : 密执安州立大学董事会 The Date of File Acceptance : 28.10.2009 Release Date : 21.09.2011

Foldable OLEDs have substrates made of very flexible metallic foils or plastics. Foldable OLEDs are very lightweight and durable.

PATENTS Oled Foldable Display Structures Inventors : James W. KANG Applicant : James W. KANG The Date of File Acceptance : 10.08.2012 Release Date : 21.02.2013

How is flexible OLED different from OLED??

Thickness As the thickness of the glass decreases it becomes more flexible. Polymer has less stiffness even though if the thickness of it is high comparatively.

Thermal & Dimensional Stability Glass exhibits same Stress & Strain at 250C and 1500C when compared with PEN & Polymide. At higher temperatures Glass does not change it shape or size but Plastic has distortions.

Device Performance Optimization

Ultra-good barrier needed Very low permeation rate in flexible OLED: - 10-6 g/m2/day of WVTR - 10-6 to 10-3 cm3/m2/day of OTR Increase Lifespan by 10,000 hours Barriers in production: glass or metal flip Barriers in OLED is 1 million times stronger than typical package of a potato chips!

Flexible Electrode Material

PATENTS Flexible Oled Card Inventors : Claudio CRINITI Applicant : Claudio CRINITI The Date of File Acceptance : 10.04.2012 Release Date : 12.09.2013 Oled With Flexible Cover Layer Inventors : Petrus CORNELIS, Paulus BOUTEN Applicant : Koninklijke Philips Electronics N.V. The Date of File Acceptance : 23.09.2011 Release Date : 15.08.2013

CRT

CRT

PLASMA

PLASMA

LCD

LCD

LCD

LED

LED

LED

OLED technology is finding its niche in a variety of applications because it is able to provide a number of advantages: Flexible:   It is possible to make OLED displays flexible by using the right materials and processes. Very thin:   OLED displays can be made very thin, making them very attractive for televisions and computer monitor applications. Colour capability:   It is possible to fabricate OLED displays that can generate all colours. Power consumption:   The power consumed by an OLED display is generally less than that of an LCD when including the backlight required. This is only true for backgrounds that are dark, or partially dark. Bright images:   OLED displays can provide a higher contrast ratio than that obtainable with an LCD. Wide viewing angle:   With many displays, the colour becomes disported and the image less saturated as the viewing angle increases. Colours displayed by OLEDs appear correct, even up to viewing angles approaching 90°.

Fast response time:   As LCDs depend upon charges being held in the individual pixels, they can have a slow response time. OLEDs are very much faster. A typical OLED can have a response time of less than 0.01ms. Low cost in the future:   OLED fabrication are likely to be able to utilise techniques that will enable very low cost displays to be made, although these techniques are still in development. Current costs are high. [18][2] OLED displays do have their disadvantages: Moisture sensitive:   Some types of OLED can be sensitive to moisture. Limited life:   The lifetime of some displays can be short as a result of the high sensitivity to moisture. This has been a limiting factor in the past. Power consumption:   Power consumption can be higher than an equivalent LCD when white backgrounds are being viewed as the OLED needs to generate the light for this which will consume more power. For images with a darker background power consumption is generally less. UV sensitivity:   OLED displays can be damaged by prolonged exposure to UV light. To avoid this a UV blocking filter is often installed over the main display, but this increases the cost.[2]

Lifespan: The lifespan of the OLED displays is a major problem Lifespan:   The lifespan of the OLED displays is a major problem. Currently they are around half that of an LCD, being around 15 000 hours. The blue OLEDs life is too short. Colors are as in the figure, the lifetime of OLEDs ; [18][2] Current performance of new phosphorescent materials

CONCLUSION

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