Flexible OLED display and flexible OLCD: How do these differ?

Paul Cain, Strategy Director

October 18, 2017

For most of us the first flat panel display in our lives was a TV or monitor. Ever since then the use cases have continued to grow, from smartphones and smartwatches to car dashboards and control panels, and new display technologies will only accelerate this. With the proliferation of smart home appliances, there are increasing number of new display applications, for example in voice-enabled devices and white goods. In the future, we can imagine displays being embedded into almost any object, bringing surfaces to life in ways not possible before.

Flexible displaysOrganic light emitting diode (OLED) displays and liquid crystal displays (LCD) are the most popular active matrix display technologies today with LCD holding nearly 90% of the market, in particular because of its scalability to large sizes. Thanks to technological progress both OLED and LCD can now be made flexible. But how do they differentiate and what market applications do they target?

Flexible OLED display

OLED displays offer great front of screen performance in terms of contrast, colour gamut and refresh rate. They also can be made onto Polyimide (plastic) substrates, making them even thinner, conformable and shapeable compared to their glass counterparts, leaving more room for other components (such as batteries). These properties open up new designs such as seen in the Samsung Galaxy Edge and Apple X phones.

Today flexible OLED displays variants are expensive to manufacture for several reasons: the cost of materials used, and the process complexity means that yield is relatively low at present, and gets even lower for larger displays. Secondly, the lifetime of OLED displays, particularly on flexible substrates, is fine for consumer electronics applications, but not yet at a point where it can be used for higher specification applications such as automotive. This is because the lifetime of OLEDs is inversely proportional to the square of the pixel brightness – but applications such as automotive need both long lifetime and high brightness. Nevertheless, flexible OLED displays are a strong option for consumer electronics that require smaller displays, such as mobile phones and smart watches.

Flexible OLCD

At FlexEnable we have developed a complementary type of flexible display called organic LCD (OLCD) that can meet the requirements of applications for which OLED isn’t suitable. This is an active matrix LCD display built using an organic thin-film transistor (OTFT) backplane, allowing the whole display to be manufactured on a rugged plastic substrate with excellent optical performance. OLCD is extremely thin, light and shatterproof, and can be conformed to different surfaces and even cut into shapes.

Both OTFT and LCD involve relatively simple manufacturing processes (in terms of number of steps), and both can be easily scaled to very large sizes using existing production lines (in fact, the largest LCD lines in the world are being built to handle substrates up to 2.9m x 3.4m). The low temperature process deployed by the OTFT backplane means that it can be processed on low cost plastic like TAC film. A simple handling method is used where the TAC is released from the glass with ~100% yield regardless of size.

Furthermore, OLCD can be used to make very bright displays without reducing its lifetime (unlike OLED). The lifetime of OLCD is independent of the display brightness as it is achieved through the transmission of a separate light source (the backlight), rather than emission of its own light.

Therefore, for flexible display applications that require either large area and/or high brightness with long lifetime, OLCD is the perfect choice. This includes applications in automotive, home appliances, digital signage and other consumer electronics where large area, low cost flexible displays are needed.

FlexEnable is currently working with its first manufacturing partner, Truly Semiconductors, to transfer the processes for flexible OLCD into existing LCD production lines in China with volume production expected in late 2018. Soon OEMs, Tier 1s and end user companies will have access to this innovative display technology and we’ll be seeing the first products that have a curved or shaped OLCD.

If you want to find out more about flexible OLCD, get in touch with us at info@flexenable.com

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