FoD makes a new and stronger argument for fingerprint sensing
When Apple unveiled its Face ID mechanism to unlock the new iPhones, not a few believed that the traditional fingerprint sensing method would soon fade into oblivion. Now an update that will feature more advanced functionality is being championed by Android phones as their technology of choice for biometric identification, marking something of a comeback for fingerprint sensing.
The new mechanism is called fingerprint on display or FoD, which pairs best with smartphones that use a full-screen display in which the fingerprint sensor on the front of the screen is invisible. FoD will also be a competitive feature that seeks to replace other biometric identification methods for mobile phones, such as iris recognition and facial recognition.
Shipments of FoD modules this year will reach nearly 200 million units, IHS Markit data show, up nearly 580% from a low base figure of approximately 29 million units in 2018, according to the Display Fingerprint Technology and Market Report - 2019 from IHS Markit. Shipments in 2019 could go as high as 240 million units if some influential factors, including the availability and price of FoD modules, turn out to be favorable for the year.
Among those currently deploying FoD solutions in their smartphone offerings are top Chinese name brands like Vivo, Huawei, Xiaomi, Oppo, and Lenovo, as well as South Korea's Samsung.
Chinese maker Goodix is the FoD solutions provider to Vivo and Huawei, while fellow Chinese manufacturer OXI supplies FoDs to Lenovo and very likely to Xiaomi and Oppo.
Samsung, meanwhile, has adopted California-based Qualcomm's ultrasonic FoD technology for its latest Galaxy S10 and Note 10 smartphones. For its Galaxy A series with models in both the high-end and midrange segments, Samsung will use the FoD optical imaging solution of Taiwan's Egis Technology.
Demand for FoDs by Samsung will likely reach 70-80 million units this year, IHS Markit forecasts show, while the top Chinese brands will need 120-130 million units.
Even newer solutions being developed
Despite their increasing use on 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 AMOLED displays. This is because on thin-film-transistor (TFT) LCDs—the other type of display besides AMOLED used for mobile phones—the displays have a backlight hindering reception of the FoD sensor, an issue that can't be resolved quickly at present or within the immediate term.
Moreover, FoD modules are currently incorporated as add-on components under the display, a method that increases the overall thickness of the entire display assembly. Last, 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 even though the FoD market is just taking off. The new solutions 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 in place to develop an embedded in-cell sensor structure to compete with the current add-on under-display fingerprint mechanism.
The TFT LCD approach will gain traction over time, projections show. Last year, silicon-based FoD sensor solutions were dominant in the market and made up 91% of total FoD shipments. However,TFT-based FoD sensor solutions will account for 32% of FoD shipments this year. And if embedded in-cell FoD solutions for TFT LCD displays can be developed by 2020 or 2021, TFT-based sensor shipments will grow considerably, IHS Markit believes.
By then, the only holdout to TFT-sensor solutions would be Apple. Even so, the FoD technology will have already scored major victories, not only replacing add-on, silicon-based fingerprint sensors on high-end smartphones, but also extending its penetration to midrange smartphones, as cost and production efficiencies resulting from the use of TFT sensing become apparent.
Calvin Hsieh is director for displays at IHS
Posted 9 May 2019
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