By Craig Guthrie, deputy editorA wave of fingerprint sensor deployments on smartphones this year has been accompanied by increasing variety in the formats being implemented.From the iPhone's Touch ID in the home button to rear and even side-mounted sensors on other devices, the industry seems undecided on what placement offers users more stability and security.For some firms, the future of touch fingerprint readers is invisible – that is, the sensors will be unseen, residing under a touchscreen.Human interface firm Synaptics has taken a lead in this area, revealing plans earlier this year to launch an under-glass fingerprint sensor solution within 12 months.Planet Biometrics talked to Alfred Woo, senior director of Marketing and Communications at Synaptics, about the swirling trends and what will eventually dominate.What led your research team to develop the in-glass solution?It's important to first understand the three types of in-glass fingerprint sensing. The most basic level is to embed the sensor below a thickness of glassy material, such as glass, ceramics, or sapphire. This results in a button much like the Apple TouchID button; a smooth, durable surface that is appealing visually, and resistant to scratches and wear.The next level of in-glass sensing would be to embed the sensor under the lens glass on a phone or tablet, but under the non-display area. This is a bit more complicated than implementing it under a glassy button. The lens needs to be glass (ceramics and sapphire are either too costly or visually opaque), and the lens glass must meet a minimum thickness to be durable and break-resistant. Relative to glassy buttons, under-inactive-glass-lens sensing provides additional industrial design benefits (i.e., the front of the device can maintain a flush, hole-free appearance).The highest level of in-glass sensing would be to embed the sensing functionality to be co-existent with the display. In this case, normal usage of the touchscreen can also authenticate the user. No specific user actions are needed, so this results in the simplest, most convenient, and most seamless authentication experience possible.Synaptics is driven to provide the highest-quality product and most optimal user experience to our OEM customers. Our underglass technology trajectory enables us to deliver a portfolio of high-value benefits, excellent performance and durability, optimized industrial design, and revolutionary user experiences.What are the specific trends in the future evolution of human interfaces and biometrics?In the next few years, we see increased fusion of multiple biometrics (multimodal biometrics), passive or persistent biometrics (to simplify the user experience). Additionally, we will see increased hardware/software integration to simplify the incorporation of biometrics into device, and reduce costs.These trends will be the catalyst to an omnipresence of biometric authentication and identification. Devices will always know who “you” are and customize user experience and tailor content to individuals. This will all occur as the human interface transcends the personal device, so much that these devices become practically invisible. We are still in the infancy of the technology lifetime; the developments of the next few years will optimize security and convenience, and bring the benefits of biometrics to more use cases than online authentication and mobile payments.Will the newer range of biometric PC peripheral solutions overcome the user acceptance issues of say, laptop sensors in the early 2000s?User expectations and usage models for PC devices have come a long way in since the early 2000s. With the rapid adoption of fingerprint sensors in mobile phones, users are now very accustomed to biometrics for password alternatives. Now users expect the same level of convenience and security on PCs that they have on their smartphones. Decades ago, PCs were used for local computing, but are now primarily used as portals for online shopping, financial transactions and social media. The value of safeguarding this digital persona is very high and passwords cannot offer the same level of protection. Biometrics are far more secure and easy-to-use.Simply put, the value equation is very different now than it was in the early 2000s. The value of security, especially online security, is paramount today.How useful is the 2013 acquisition of fingerprint authentication firm Validity proving?The acquisition of Validity has enabled Synaptics to become the leading supplier of fingerprint devices in the consumer electronics markets. Our leadership extends into a wide range of segments: the smartphone, tablet, and PC markets, with over 200 million fingerprint sensors shipped to date.How does Synaptics feel the market is progressing in segments beyond smartphones?Biometrics adoption in smartphones is driving traction in other segments. The security and user experience benefits of biometrics in smartphones is very portable, and these benefits are expected to extend across all connected devices. We have seen a surge of interest for fingerprint sensors for tablets, notebook PCs, desktop PCs, PC peripherals, and even wearables. Once users experience the benefits of fingerprint on their smartphone, it becomes natural to expect it everywhere else and a noticeable deficiency when not available.