Over the past year, display fingerprint sensing technology—also known as fingerprint on display (FoD)—has been optimized by suppliers and widely adopted by smartphone brands, putting FoD module shipments on track to reach nearly 200 million units in 2019, up 577 percent from 2018.
According to the Display Fingerprint Technology & Market Report - 2019 by IHS Markit, the market will continue to expand in the coming years, reaching 600 million units in 2023.
FoD allows users to unlock their smartphones simply by touching the display. This lends to a user-friendly experience that is competitive with other biometric identification methods for mobile phones, such as facial recognition.
The success of FoD reflects smartphone brands’ rising confidence in the future of fingerprint ID technology. While Apple has used its Face ID mechanism since 2017 to unlock the iPhone, Android phone makers now are championing FoD by as their technology of choice for biometric identification.
Android smartphone brands embrace FoD
Companies currently deploying FoD solutions for their smartphones include South Korea's Samsung Electronics, as well as top Chinese name brands like Vivo, Huawei, Xiaomi, OPPO and Lenovo.
Samsung has adopted ultrasonic FoD technology for its latest Galaxy S10 smartphones. For its Galaxy A series with models in both the high-end and midrange segments, Samsung is using an FoD optical imaging CMOS image sensor (CIS) solution.
Despite their increasing use in Android phones, current FoD solutions—whether they are CMOS image-sensor-based optical imaging mechanisms or solutions utilizing ultrasonic technologies—can be used only with active-matrix organic light-emitting diode (AMOLED) displays. FoD technology presently is incompatible with thin-film-transistor (TFT) liquid crystal display (LCD) panels that also are widely used in mobile phones. That is because TFT-LCDs must employ backlights, which hinder the reception of FoD sensors.
FoDs also have other drawbacks, including the fact that their modules are currently incorporated as add-on components under the display, a method that increases the overall thickness of the entire display assembly. Furthermore, the fingerprint sensing area for FoD is limited because the current silicon wafer process is too expensive to produce a bigger sensor capable of yielding a larger sensing area.
In response to these limitations, the industry has been developing several new FoD solutions. These include the use of TFT-based sensors, which will compete with the silicon-based CMOS image sensors being utilized today. Improvements to the TFT process are also being sought to enlarge the fingerprint sensing area, and efforts are likewise underway to develop an embedded in-cell sensor structure to compete with the current add-on under-display fingerprint mechanism.
The TFT approach will gain traction over time, projections show. In 2018, silicon-based FoD sensor solutions were dominant in the market, making up 91 percent of total FoD shipments. However, TFT-based FoD sensor solutions will rise to account for 32 percent of FoD shipments in 2019.
If embedded in-cell FoD solutions that are able to work with TFT-LCD displays can be developed in 2020 or 2021, TFT-based sensor shipments will rise considerably, IHS Markit believes.
The Display Fingerprint Technology & Market Report by IHS Markit focuses on the latest invisible display fingerprint sensing integrated with the display to provide biometric identification. The report examines emerging technology trends, supply chain relationship, module cost modeling, competition, and impact on TFT-LCD and AMOLED displays.