EBN – YJ Kim – Summer School for Buyers: OLED Screens



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As technology evolves, the nomenclature of new products changes with them. For the purchasing department, this often results in new product lines, new suppliers and a variety of changes in the supply chain. In this four-part series, we will briefly summarize how organic light-emitting diode (OLED) technology works and how technology has evolved to help buyers improve their skills without obtaining an engineering degree.

start, let's look at where technology has been.

Types of flat screen

The flat panel display technology is divided into two types: non-emissive display, which requires an external light source and an emissive screen, which produces its own organically light. The thin film transistor (TFT) is a non-emissive and old display technology that requires an external light source, while OLED is considered an emissive display technology that does not require backlighting because each pixel provides its own lighting. OLED has three self-emitting phosphorescent organic compounds: red, green and blue. An OLED display uses the emissive phenomenon of three-color phosphorescent organic compounds combined with electrons emitted by anodic and negative positive cathodic particles.

Evolution of OLED

OLED technology, according to the driver scheme, is divided into two categories: Pbadive Matrix OLED (PM) and Active Matrix OLED (AM). PM OLED technology drives the screen to emit light by placing voltages in both the vertical and horizontal axes of the light-emitting diodes arranged on the screen and producing light at the point of intersection.

PM OLED, a simple low-cost manufacturing structure, is difficult to produce a larger-format, high-quality screen because the larger screen size results in an exponential increase in power consumption. ;energy. This causes a sharp decrease in the life of the battery and the availability of the device. As a result, PM OLED technology can usually be found in small form displays such as smartphones and wrist-based fitness trackers.

To compensate for the disadvantages of PM OLED, AM OLED has become an ideal technology for smartphones and other medium and large screens, including automotive and consumer applications such as widescreen TVs. AM OLED is ideal for these applications because each light-emitting diode has a built-in thin-film transistor to individually control each light-emitting diode, eliminating the need for a backlighting of the screen. This, in turn, reduces energy consumption and allows thinner form factor devices.

Advantages of OLED

OLED has various advantages thanks to its self-emissive characteristics. In terms of color gamut, liquid crystal displays (LCDs) can not produce their own light, which requires a backlight on the back of the screen and the light emitted by the backlight pbades through a crystal liquid and a color filter. loss of purity of color. However, the self-emitting feature of AM OLED, which is not sensitive to the loss of purity of color, can achieve a color representation close to the "real life". AM-OLED also consumes less power than LCD. As each pixel emits light itself to display the color, no pixel is lit to represent the color black. However, the backlight is always lit on an LCD screen, which does not allow a color "true black".

Without backlighting, no light leakage occurs, allowing a high contrast ratio, making OLEDs more suitable for readability of the mobile device in outdoor environments. And without backlighting, OLED smartphones can be thinner than LCD models, which allows thinner and lighter mobile products, and allows more space for a larger battery, which means more power. use between refills. In addition, OLED is more comfortable on the eyes because its self-emissive mechanism is known to emit less dangerous blue light in the wavelength of 415 nm to 455 nm (up to 50% less than LCD), which can damage the retina. also offers a fast response time, which allows a motion "without blur", which means clearer limits for moving objects without video screen delay. This feature meets the requirement of fast response time of HMD (Head Mounted Displays) used in VR / AR, as well as various display applications including TV, tablet, smartphone, and a wide expected range of Other applications.

take advantage of OLED's flexible display capabilities, which can be folded, rolled or folded. This will play a key role in the growing and highly competitive mobile market, where differentiated design is critical to success. Since the flexible display OLED AM has successfully entered mbad production in 2013, products of different formats have been launched and the freedom of design offered by OLED will further innovate in the years to come.

Applications with OLED

The OLED product went into mbad production in 2007, the OLED display has been used in various applications. Initially, OLED had a high unit price, and due to some technical constraints, it was adopted only for external display of mobile devices such as MP3 players. However, after the launch of Samsung's Galaxy S OLED AM in 2010, the use in the smartphone market has grown rapidly. AM OLED displays have increased significantly with a corresponding increase in demand for DDIC OLED.

In addition, Samsung's first AM OLED Tablet PC, Galaxy Tab 7, arrived in 2012. This indicates that the OLED display has surpbaded smartphones and was becoming more widely adopted for various mobile computing devices . Around the same time, portable gaming devices and digital cameras also began adopting AM OLED displays, expanding the range of applications for OLED DDIC. OLED displays are now appearing in other consumer electronics products such as HMD for VR / AR applications.

Paul Kim, vice president of marketing, Standard Products Group, MagnaChip Semiconductor Corp., co-authored this article. Kim became Vice President of Marketing at Standard Products Group in December 2015. He joined MagnaChip in August 2011 and was Vice President of Display Design, Display Solutions Division. Prior to joining MagnaChip, Kim was a senior engineer in the SOC and Display Driver design group of Samsung Electronics, where he worked from 1994 to 2010. Kim holds a B.Sc. in Electrical Engineering from Inha University, Korea. [ad_2]
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