Should I consider AMOLED?

Mike Logan
Display & Input Technology Manager
Should I consider AMOLED?
LED technology is now being used for many applications not envisaged years ago. One variant of LED technology namely AMOLED, active-matrix organic light-emitting diode, technology is a form that is being used increasingly.

AMOLED technology is an increasingly viable option for industrial displays, and displays based on this technology are now affordable with realistic MoQs for mid-high volume industrial, medical and specialist consumer electronics. So is the new kid on the block a good choice for your project, or if you’re better off staying with tried and trusted TFT?

When choosing the most appropriate display technology for a given application, price, availability and performance are always the key factors to consider. Display technologies differ significantly in terms of viewing angle, brightness, response time, power and size.

Superior performance

As it represents an evolutionary step in display technology, it follows that AMOLED should offer gains in terms of the performance metrics mentioned, and it does. AMOLED displays offer a wider viewing angle than TFT LCD displays, yet are significantly thinner in profile (see below for an overview of the construction of AMOLED technology). Their construction also allows more of the light to reach the top layer (normally glass) and so they are generally perceived as being brighter, too. Manufacturer’s data shows that for a given luminance of, say, 150cd/m2, AMOLEDs can appear almost 50% brighter than TFT-LCDs.

In practice, this means that a TFT-LCD display would need to be brighter (use more power) to appear as bright as an AMOLED display, particularly in sunlight. Conversely, the AMOLED display could operate at lower power and still be readable in direct sunlight.

For industrial and medical applications, operating temperature can be critical. AMOLEDs compare favourably with even the best TFT-LCDs, making them suitable for environments that would be considered harsh in terms of consumer applications, but are standard in industrial, medical and automotive markets.

These benefits ensure that AMOLED displays will successfully transition from the very high volume consumer (smart phone) market, to medium and high volume applications commonly found in all other sectors.

By way of illustration, Truly Semiconductors is one of China’s largest manufacturers of small and medium sized display modules, producing both AMOLED and TFT-LCD displays. Its own data shows that AMOLED offers superior performance in terms of contrast ratio and response times.

This alone would make it more applicable in many devices, but the benefits extend to include lower dynamic power, further widening the potential applications to include portable equipment, such as home health care (another burgeoning sector), and the Industrial IoT.

AMOLED technology offers much higher response rates than TFT-LCD. High response times directly influence the update rate; for a frame rate of 60 frames per second (60Hz), a minimum response time of 16ms would be required. It follows that a higher response rate results in a clearer image. This can be particularly important in industrial or medical applications, where the clarity of the image could be crucial.

TFT advantages

Although AMOLED wins in terms of performance and size, it is certainly not right for every application.

The most immediate issue is cost. AMOLED technology comes at a premium of 100% compared to standard TN TFT displays, and 50% compared to TFT IPS technology, which in truth offers very similar viewing angle and brightness to AMOLED though is somewhat larger and more power hungry.

MOQs for AMOLED technology are also higher. Although we can offer AMOLED for industrial applications, MOQs are still of the order of 50,000 per year – much less than the millions required even a short time back, but still too high for many industrial applications. Leadtimes are also longer on AMOLED – roughly double that on TFT at present.

Finally, lifetime can rule out AMOLED in professional electronics applications. Consult the datasheet for the operational hours on your preferred AMOLED or TFT display, but expect in the region of 20-30,000 hours for AMOLED and 50,000 hours for TFT.

Conclusion

There are strong technical and commercial reasons for choosing AMOLED technology when developing the next-generation of industrial, medical and automotive applications. Its superior performance, flexibility (often literally) and availability compare favourably with existing display technologies and it is destined to become a popular choice with OEMs and their customers. 

 

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