Apple's Patent Background

One relatively common biometric sensing device today is the fingerprint sensor. These devices are used in controlling access to electronic devices such as computers and mobile phones, safes, buildings, vehicles, etc. by scanning a user's fingerprint and comparing it to an authenticating set of fingerprint images. If the proffered (live) fingerprint to be authenticated matches one within a set of pre-enrolled authorized fingerprints, access may be granted. Fingerprint sensors may be stand-alone devices, integrated into other devices such as PC peripherals, or may be integrated into the devices over which they control access. The sensors may be optical or electrical (e.g., resistive, capacitive, etc.)

Apple Invents Bezel Centric Fingerprint Sensor Assembly

One aspect of Apple's biometric sensor assembly such as a fingerprint sensor, comprises a substrate to which is mounted to a die containing sensor circuitry and at least one conductive bezel.

Apple states that technically, "bezel" means a unitary, substantially uniformly composed structure, most typically metal or conductive plastic. The die and the bezel are encased in a unitary encapsulation structure to protect those elements from mechanical, electrical, and environmental damage, yet with a portion of a surface of the die and the bezel exposed or at most thinly covered by the encapsulation or other coating material structure.

By encasing both the bezel and the sensor die in the encapsulation structure, the elements may be brought closer together than otherwise possible. In addition, the encapsulation structure physically protects the bezel and sensor die, and in particular maintains the spacing therebetween in a fashion that isn't possible by currently known device designs.

According to one variation described in the patent, the bezel may be an electrically conductive arch-shaped structure secured to a substrate. The substrate may have leadlines or the like formed thereon to allow electrically interconnection between the bezel and other circuitry. The bezel may alternatively be a solid body or part of a bezel frame. A single bezel may be integrally molded with the sensor die in an encapsulation structure. The bezel may be adjacent a single side of the sensor die, several sides of the sensor die, or may surround the sensor die.

The molding of the bezel and sensor die may be such that the top surface of the bezel and the top surface of the sensor die are coplanar. In this case, the top surface of the bezel may protrude slightly above the encapsulation material, for example to improve physical contact therewith by a user's finger.

In patent FIG. 1 noted below, the bezels are in a discrete arch (or inverted "U") shaped metal structures, which may be individually secured to bezel receiving regions.

One or more bezels (noted as patent point #18) are secured to bezel receiving regions 20 on a substrate such as a printed circuit board (PCB). The bezels may be discrete individual elements, or may form part of a bezel frame. The bezels may be opaque, conductive elements used, for example, to inject current into the finger of a user as the finger is being sensed by the pixels of a two-dimensional array (noted as patent point # 16).

Apple's patent FIG. 3A is a perspective view of a bezel frame and patent FIG. 5 is a top or plan view of the biometric sensor with integrally molded bezel and sensor die illustrated in FIG. 1.

In Operation

In operation, a user swipes a finger over a surface of the sensor. The sensor captures a number of thin strips of the fingerprint as the finger is swiped, and the complete fingerprint is assembled in software for use in authentication. Such a sensor apparatus is typically preferred when a compact sensor is desired.

When viewed from above, the sensor is the approximate width and length of an average user's fingertip. In operation, the user holds their fingertip in place over the sensor area, and the fingerprint is scanned, typically in raster fashion. Such sensors are typically referred to as area sensors.

Similarly, a second area sensor embodiment 110 is shown in FIG. 10 below, in which a bezel 112 is in the form of a rectangular ring fully surrounds an area sensor die 114, integrally molded in an encapsulation structure.

Patent Credits

Apple credits Robert Bond, Alan Kramer and Giovanni Gozzini as the inventors of patent application 20130154031 which was originally filed in Q1 2013.

In light of the lastest PRISM revelations, fingerprint scanning technologies will naturally be under scrutiny by the public going forward. Although Apple's press release was honest, I think that the some of the public will be a little skeptical about activating fingerprint scanners on future iDevices.

What is your take on this? Will a fingerprint scanner built into a future iPhone now be perceived as a negative or still an overall positive if it's tied into an iWallet security feature?  Send in your feedback below.

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