Qualcomm claim fingerprint sensor breakthrough

Semiconductor giant Qualcomm has announced an innovative new fingerprint sensor for use in mobile devices such as smartphones. They claim that their Snapdragon Sense ID 3D fingerprint technology is able to read fingerprints through glass, plastic and even metal.


The average person is estimated to have around 20-25 online accounts, each of which it is recommended should have a unique password of at least 8-12 characters. With so much to remember, many see biometric authentication – such as fingerprint readers – as the solution.

Most existing electronic fingerprint readers use either an optical or capacitance sensor. Optical sensors capture a visual image of the finger in a similar way to as digital camera. But struggle to record an accurate image if the finger or sensor surface is dirty, or if the fingerprint is eroded. They are also easily fooled by a false finger or image of a fingerprint, so it is necessary to incorporate an additional sensor to detect ‘live’ fingers.

Newer fingerprint readers, such as Apple’s Touch ID, image using capacitance – the same principal used by most touchscreens on smartphones and tablets. Capacitive sensors are more effective at reading dirty or eroded fingerprints than optical sensors. But they are susceptible to damage from electrostatic discharge, and can still be tricked into authenticating a fingerprint copy.

Qualcomm say Snapdragon Sense ID is the first mobile system based on ultrasonic imaging. Ultrasonic sensors use the same principals as medical ultrasonography. Piezoelectric transducers generate high-frequency sound waves and the reflected energy is measured to produce a three-dimensional image.

This technique is capable of penetrating the skin and imaging the sub-surface dermal skin layer. As this exhibits the same characteristic fingerprint pattern as the surface layers of skin (epidermis), the problems of dirt and erosion are eliminated.

It should also be much more capable at distinguishing between an original fingerprint and a copy. But some security experts consider all biometric security to have a fundamental flaw – passwords are easily changed, but once your fingerprint or other biometric data has been compromised it can never be revoked.

Qualcomm expect commercial devices using Snapdragon Sense ID to be available in the second half of 2015.