Pixel 9 series to ditch optical sensor for an ultrasonic fingerprint sensor

Following user frustrations with the under-display fingerprint sensor introduced on the Pixel 6, Google appears to be making a change with the Pixel 9 series. 

According to a report by Android Authority, the Pixel 9 and 9 Pro will replace the current optical sensor in favor of an ultrasonic fingerprint reader. The Pixel 9 Pro Fold, however, is expected to maintain its side-mounted capacitive sensor.

Ultrasonic fingerprint technology utilizes inaudible sound waves to map a user’s fingerprint. This method offers several potential advantages over the optical sensors used in previous Pixels. 

Unlike optical sensors that rely on light and can be hampered by screen protectors, ultrasonic sensors can create a more detailed “reproduction” of the fingerprint ridges and valleys, leading to faster and more reliable unlocking. 

The specific ultrasonic sensor rumored for the Pixel 9 is the Qualcomm 3D Sonic Gen 2 (QFS4008). Introduced in 2021, this sensor boasts a larger surface area (8x8mm) compared to its predecessor which allows for easier finger placement and captures more biometric data for improved accuracy. 

Additionally, the QFS4008 is claimed to be faster than previous solutions, particularly when fingers are wet – a common pain point for optical sensors. It’s the same sensor used on the Galaxy S24 Ultra. 

Google’s decision to switch to fingerprint sensor technology is not surprising. Since the Pixel 6, users have reported inconsistent performance with the under-display sensor, especially compared to the highly regarded rear-mounted Pixel Imprint scanner used on earlier models. 

While Google made improvements with the Pixel 6a sensor, limitations like a reduced number of registerable fingerprints remained. 

The delay in adopting ultrasonic technology is somewhat puzzling. Fortunately, there is universal face unlock on the Pixel 8 that worked quite well. However, face unlock has its limitations. 

Its reliance solely on the front camera renders it unusable in low-light conditions, highlighting the need for a robust alternative like a reliable fingerprint sensor.