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Sprint Product Ambassadors: How Does the Galaxy S5 Fingerprint Scanner Work?

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Sprint Product Ambassador

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We all know the fingerprint scanner in the new Galaxy S5 is pretty cool.  In fact it's beyond cool; it's actually USEFUL.  I use it several times a day every time I unlock my phone and feel much more secure now than I used to with a pattern lock.  I love it and find myself swiping the home buttons of other Android phones only to be disappointed when they don't magically unlock like my S5 does.

BUT as much as I use it, I never realized that beneath that button, some pretty cool stuff was going on.

The scanner on the S5 is powered by Validity Inc, a company specializing in biometric security and authentication that was recently acquired by Synaptics.

Validity fingerprint sensors are the world's highest performance, most flexible and cost effective devices for handsets, tablets and notebook computers. The devices feature an industry-leading sensing performance using the company's patented LiveFlex™ technology that provides superior image quality with high-frequency RF imaging into the live layer of the finger.

Supported fingerprint  device implementations range from “invisible” under-glass sensors for handsets,  to home and power buttons for

mobile devices, and a variety of designs for  notebook computer palm rests.

The combination of low  cost, large sensing area, and design flexibility come from Validity’s patented  Chip-On-Flex architecture, in which the fingerprint IC is separate from the  sensing area. This contrasts with competing  devices in which the sensing area is the IC, which results in a tradeoff  between cost and performance and which limits design flexibility for  space-constrained devices.

For design  flexibility, Validity supplies products with SPI and USB interfaces. Security and encryption levels range from  full encryption for enterprise devices to Secure Match™ and One-Time Passwords  for consumer devices.  With an ultra-low 10µA finger detect current, the VFS61xx supports wake on finger for mobile  devices.

Validity provides  a full suite of development tools for both Windows™ and Android, speeding up  time to market for OEMs and ODMs wishing to incorporate Natural ID™ into their  designs.

Source: Validity

Validity prides itself on the accuracy of it's LiveFlex scanner solution for handsets and tablets, with a claim of one false swipe per million, more precise and scoring higher than any other solution out there, even Authentec's solution which powers the scanner on the iPhone 5S.  It also augments that accuracy with strong encryption of the print data and adds additonal features of precision by penetrating into the skin layer where fingerprints are formed to mitigate issues with misreads caused by dirt, callouses and other factors that can affect other readers.

Highest Performing Fingerprint Sensors  for Handsets, Tablets and PCs

Devices feature industry's best security, design flexibility, and touch navigation

Validity's patented LiveFlex® fingerprint sensor technology provides significant improvement over all other fingerprint sensor technologies by delivering industry-leading FAR/FRR performance with as few as one false accept in one million swipes with a nearly 100% enrollment rate. Validity sensors provide enterprise-grade security by taking a system-based approach extending far beyond simple password replacement. Validity sensors feature SecureMatch™ protecting system credentials by verifying the fingerprint sent to the host processor with the one matched on-chip; one-time passwords (OTP) for securing remote transactions; and RSA public key encryption, AES-256 data encryption, SHA-256 hash algorithm, and SSL cryptographic protocol for protecting the secrecy of fingerprint images, templates and other transmitted data.

  With built in touch-based navigation functionality, Validity sensors also greatly enhance smartphone and tablet user functionality.  Full 360 degree cursor control is provided as is scrolling, simplifying navigation and selection with today's larger touch-based devices.

Patented LiveFlex Architecture

The company's Patented LiveFlex technology provides industry-leading fingerprint imaging performance through the use of high-frequency AM-modulated RF signals to penetrate into the skin's inner live layer to scan where the fingerprint is formed, minimizing effects due to dirty, worn, or calloused skin.   Additionally, the LiveFlex architecture separates the sensor from the IC, resolving fundamental cost challenges while maintaining excellent imaging quality by moving the fingerprint sensing elements off the silicon die.

LiveFlex sensors enable solutions ranging from invisible, under-glass sensors for smartphones; buttons for handsets and tablets; and the world's thinnest palm-rest designs for Ultrabook® computers.

In addition, their "Chip-on-Flex" implementation is more cost effective and involve smaller, more affordable components then other solutions out there.  This also allows the scanner to be placed into a myriad of button types, shapes, sizes and placements on the device, not just being relegated to the home button.

Chip-on-Flex (COF) Implementation

Validity sensors are constructed using a Chip-on-Flex (COF) architecture where a fingerprint IC (the "chip") is attached to a flexible circuit board (the "flex").  The flex consists of a very thin, low-cost metallized Kapton™ film, in which the metal traces patterned in the film form the sense elements of the fingerprint sensor.  These traces are both driven and sensed by the fingerprint IC.

This patented method of separating the sensor element from the IC allows Validity to follow a traditional die-shrink product roadmap while maintaining the highest performance and design flexibility.  This is in contrast to competing products where the sensor is the silicon, and therefore the silicon cannot be shrunk without severely degrading FAR/FRR performance, and where novel "invisible" sensor architectures cannot be readily implemented.

Buttons of Any Shape

Buttons provide another method of integrating fingerprint sensors into mobile platforms.  Virtually any shape is possible.  Shown above are round,  rectangular, and  rounded corner rectangular solutions. Contact Your local Validty representative for details on other shapes and sizes.

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So maybe you never wondered about this.. maybe you did.  But it's kind of nice to be able to look beyond the layers of the finished product and find out how features like these tick.

Maybe that's just the tech geek inside of me, but we hope you have enjoyed this anyway.

Check out the Slashgear Hands-On of the scanner if you haven't had a chance to play with an S5 yet:

Until next time,

The Product Ambassador Team

Disclaimer:
The Product Ambassadors are Sprint employees from many different parts of the
company that love technology. They volunteer to test out all sorts of Sprint
devices and offer opinions freely to the Community. Each Product Ambassador
shares their own opinions of these devices, therefore the information in this
post does not necessarily reflect the opinions of Sprint. The PA's do not
represent the company in an official way, and should not be expected to respond
to Community members in an official capacity. #sprintemployee