Fingerprint sensing techniques 0920 2007 Biometrics Tech and

Fingerprint sensing techniques 0920 2007 Biometrics Tech. and Application Dr. Hsu, Wen-Hsing

Fingerprint sensing techniques l Optical readers l l l l Electro-optical readers Capacitance l l l Silicon chips TFT RF field - AC capacitance Pressure l l Reflection Transmission Sweep, sweep with a roller Touchless TFT Resistive membrane on silicon, TFT Tactile MEMS Thermal Ultra-sound

Ink l Ink and paper are the tried-and-true way to take fingerprints, but technology has found ways to eliminate smudges and ink stains.

Optical readers l Reflection The oldest 'live-scan' readers use frustrated refraction over a glass prism (when the skin touches the glass, the light is not reflected but absorbed). The finger is illuminated from one side with a LED while the other side transmits the image through a lens to a camera. (FTIR: frustrated total internal reflection).

Optical readers -Reflection Many companies are offering such devices, this is a common technology. . Here is the example of the Compaq fingerprint reader (CMOS camera, around 2000). Generally, one fingerprint is taken at a time, but some devices are able to acquire several fingers at a time. (Rolling Fingerprint) Nagoya University uses a micro-collimator instead of the fiber optic, enabling direct fingerprint comparison.

Reflection with sweep l l Kinetic Sciences and Cecrop/Sannaedle have proposed sweep optical sensors based on this principle. Cecrop seems to have abandonned this device Kinetic Sciences Paper describing the sensor Cecrop/Sannaedle

Casio + Alps Electric uses a roller with the sensor inside. The roller acts like the prism. n. Casio n. Alps Electric As well as Digital Persona with the Firefly n. Digital Persona Firefly

Reflection touchless l TST removed the prism by directly reading the fingerprint, so the finger does not touch anything (but still need a guide to get the right optical distance). Thales (formerly Thomson-CSF) also proposed the same, but with the use of a special powder to put on the finger. The BERC lab from Yonsei University (Korea) also developped a touchless sensor (2004). (2005) TBS launch a touchless sensor with the "Surround Imaging".

Transmission l It is also possible to directly read the light transmitted by the finger.

l Mitsubishi proposes to read the fingerprint with a regular camera.

l l l NEC and Delsy (and Secom? ) use a CMOS camera which is the size of the finger, with a fiber optic in-between, the light is coming from the edges in this case. Mitsumi & NEC proposes the same but with a sweep sensor. Delsy NEC Mitsumi In July 2005, Nano. Ident unveils a flexible fingerprint sensor using polymer/organic photodetector.

TFT optical / TFT optique Philips replaces the CMOS sensor by a TFT display, used as sensor. Philips has also worked with Ethentica to combine their technologies, but without known product. LG has also studied a TFT sensor.

Other companies proposing TFT fingerprint sensors: n. Casio n. Silicon. Image. Works n. Silicon Display Technology n. Alps Electric n. Mitsubishi n. Seiko/Epson

Electro-optical readers A variant of TFT devices is the use of capacitance information instead of reflected light.

l l l Some polymers are able to emit light when properly excited with the proper voltage (generally quite a high voltage is required. This polymer is directly contacting a CMOS camera, which is necessarily the size of the finger. Generally, the finger acts as the ground, and the polymer emits light where the ridges touch. Ethentica and Tes. Tech propose such a solution. Ethentica Tes. Tech

Capacitance l After optical sensing, the measurement of the capacitance between the skin and the pixel is the most physical effect used to acquire fingerprints. Where there is a ridge or a valley, the distance varies, as does the capacitance. Because an electrical field is measured and the distance between the skin and the pixel must be very low to provide enough sensitivity, the coating must be as thin as possible (a few microns). A significant drawback is vulnerability to strong external electrical fields, the most dangerous being ESD (Electro-Static Discharge).

Silicon chips + capacitance Silicon chips can be seen as a variant of the CMOS cameras: instead of using the light, another physical effect is used. Companies proposing (or having proposed) capacitance sensing: l. Veridicom, Fujitsu, Infineon, Sony, Upek, Ligh. Tuning, Melfas, Atrua, NTT, Symwave, . . .

Labs working (or having worked) on silicon capacitance sensors: Seoul University n A 600 -dpi Capacitive Fingerprint Sensor Chip and Image-Synthesis Technique (Lee & als, Seoul National University, 1998) Kaist n IML KAIST NTT n NTT Microsystem Integration Laboratories n A Single-Chip Fingerprint Sensor and Identifier (Shigematsu & als)

Capacitance + TFT n n Flat panel technology rather than bulk silicon has been studied by Philips Korea and some others, using capacitive sensing. This is still at the laboratory stage. A Capacitive Fingerprint Sensor with Low. Temperature Poly-Si TFTs Mitsubishi Electric Corp. (April 2004) Alps Electric develops 2 fingerprint sensors. One is transparent, electrostatic (capacitive).

RF field - AC capacitance l Sometimes confused with capacitance sensing, the only common point between RF field sensing and capacitance sensing is the "capacitance" connection of the signal. Companies proposing (or having proposed) RF/ACcapacitance sensing: Authentec, Fingerprint Cards

Labs working (or having worked) on RF capacitance sensing: n Labs working (or having worked) on RF capacitance sensing: Validity / Philips Korea An alternate solution consists in having connection through wires, so the finger is not mandatory directly in contact with the silicon part. n Validity

Pressure This is one of the oldest ideas, because when you put your finger on something, you apply a pressure. Piezo-electric material has existed for years, but unfortunately, the sensitivity is very low. Moreover, when you add a protective coating, the resulting image is blurred because the relief of the fingerprint is smoothed. These problems have been solved, and now some devices using pressure sensing are available. Several solutions, depending on the material, have been proposed: l l l Conductive membrane on a CMOS silicon chip. Conductive membrane on TFT. Micro-electromechanical switches on silicon chip.

Conductive membrane on silicon l Opsis (a french company) offered a device using a conductive membrane deposited on a CMOS chip (July 1994).

Conductive membrane on TFT l l Since 2002, BMF is offering a product using a TFT substrate (developed with Sanyo) Fidelica offers since mid-2004 the FIS-3002, also using a TFT substrate from Sanyo. (April 2004) Alps Electric develops 2 fingerprint sensors. One is based on pressure. l The Fraunhofer IKTS is working on 1 -3 piezocomposites to create a fingerprint sensor (for Cross. Match, 2004).

Tactile MEMS l Micro electro-mechanical devices allow engineers to make extremely tiny silicon switches. When a ridge touches a switch, it closes. But the coating remains a significant problem, and moreover, a binary image is the result, leading to minimal information. No further development has been done with this technique beyond the laboratory.

n n NTT Microsystem Integration Laboratories NTT research group n Michigan University (Wise)

l l Tima homepage N. Galy thesis page and thesis • Leti, pressure sensors (Rey)

• Ligh. Tuning Micron Technology: Tactile sensor using an insulated flexible matrix loaded with filler particles US 6, 561, 044

Thermal l l Pyro-electric material is able to convert changes in temperature into a specific voltage. This effect is quite large, and is used in infrared cameras. This type of sensor doesn't measure the difference of temperature between the skin in the ridges and valleys, because the difference is negligible. In fact, as the finger is directly placed on the material, the ridge's temperature is what's measured, as it's in contact. The valleys don't make contact, so the temperature of the pyro-electric material under the valleys remains almost unchanged. A drawback of the technique is that the image disappears quickly. When you place your finger on the sensor, there is a big change of temperature, and therefore signal, but after a short period (less than a tenth of a second), the image vanishes. The finger and the chip have reached thermal equilibrium, and as there is no change in temperature, there is no signal. This effect disappears when you sweep your finger over the sensor, because of the touch/no touch of ridge/valley. Atmel (formerly Thomson-CSF) proposes the Finger. Chip Hunno Technologies & Hyung-Kew Lee (Korea, KAIST) have studied a thermal fingerprint sensor in 1999, probably using bolometers. Nagoya University has studied a thermal sensor based on MEMS, using a resistor to heat a sensor above a cavity. INO (Institut National d'Optique / Canada) has used bolometers to make a 160 x 120 pixel fingerprint sensor (US patent 6, 633, 656). Bolometric FPA for fingerprint recording

Ultra-sound l Ultra-sound fingerprint reading is not common. It may be seen as a kind of echography. Ultra-sound sensing requires quite a big device with mechanical parts, and is quite expensive. Moreover, it takes a few seconds to grab an image. It is not suited for large production volumes at low cost. Its main advantage is the reading of the derma, the sub-surface of the skin, rather than the surface. Ultrascan Optel is still at R & D stage Surface impedance impediography (2004) Cross. Match is developping a fingerprint sensor based on piezo-electric pillars glued in teflon and covered with urethan, based on ultra-sound

Fingerprint: List of silicon sensors

List of fingerprint sensors / sensing area / JF Mainguet 2005 ( sweep sensor area sensor) Company Atmel formerly Thomso n-CSF Sensing type thermal Brand Finger Chip T Part number Rele ase date R es. dp i x pi xe l y pi xe l x m m FC 8 x 8 1997 50 8 16 0 8. 0 prototype FC 2 x 17 1997 50 8 35 0 40 17. 5 2. 0 prototype FC 15 A 1 40 1998 50 8 28 0 30 14. 0 1. 5 prototype AT 77 C 1 01 B 2000 50 8 28 0 8 14. 0 0. 4 formerly FCD 4 B 14 AT 77 C 1 04 2004 50 8 23 2 8 11. 6 0. 4 navigation 2005 5 0 8 2 3 2 8 11. 6 0. navigation & low 4 voltage I/Os AT 77 C 105 y m m notes

pressure - prot o 2004 - - - optical TFT - prot o 2004 - - - Alps/Casio optical roller - prot o 2003 Feb 600 288 - 12. 2 - sweep rolling tube Atrua capacitive - AT W 10 0 2002 363 192 8 13. 5 0. 6 Alps Formely I-Control / ICS-3000

Finger. Loc Authentec spin-off from Harris RF modulation AFS 2 2000 May 250 128 13. 0 - AFS 8500 2002 May 250 96 96 9. 75 Discontinued. AFS 8600 2004 Jan 250 96 96 9. 75 - AES 4000 2000 Sep 250 96 96 9. 75 - AES 3500 2001 Oct 500 128 6. 5 USB. Discontinued. AES 3400 2002 Sep 500 128 6. 5 - AES 2500 2002 Nov 500 192 16 9. 75 0. 81 USB. Replaced by the AES 2501 2003 Dec 500 192 16 9. 75 0. 81 USB AES 2502 2003 Dec 500 192 16 9. 75 0. 81 SSI AES 2510 2004 Jun 500 192 16 9. 75 0. 81 serial, 8 bit-parallel 1510 2005 Mar 500 128 8 6. 4 0. 4 Entr� ad 4 bit-parallel, master SSI

BMF Casio Delsy pressure TFT BLP 100 2002 Feb 438 256 384 14. 8 22. 2 BLP 60 2003 508 192 9. 6 - proto 2004 Oct 423 368 22. 08 - proto 2004 500 240 10. 0 12. 0 - CM OS 2001 508 288 384 12 18 pixel pitch is 0. 058 mm (width/height not OK) Hitachi demonstrated over a LCD display / CEATEC 2004 optical TFT optical trans. Digital Persona optical roller Ethentica electro-optical Fidelica pressure Backlight Discontinued? - CCD 2001 - 512 576 - - Fire. Fly Firefl y 2003 May 600 345 - 14. 5 - Tactile. Sense TFPM 2001 403 225 306 14. 2 19. 3 Formerly Who? Vision - FIS 3002 2004 Feb 508 256 12. 8 - 600 dpi max (500 dpi sweep dir. ) depends on speed.

Fingerprint Cards Fujitsu active capacitive Idex AC capacitive Infineon capacitive INO thermal KAIST univ. KSI / Cecrop FPC 1010 2002 363 152 200 10. 6 14. 0 FPC 1011 FPC 1030 2002 363 152 32 10. 6 2. 2 FPC 1031 MBF 110 2001 500 300 15. 0 (= Veridicom FPS 110) MBF 2001 500 256 300 12. 8 15. 0 USB. (= Veridicom FPS 200) MBF 300 2002 Mar 500 256 32 12. 8 1. 7 Discontinued. MBF 310 2003 Jul 500 218 8 10. 9 0. 4 Replaces the MBF 300. - 2000 500 256 - 12. 8 - Finger. Tip FTF 1100 2000 513 224 288 11. 1 14. 3 - FPA 2003 Sep 488 160 120 8. 3 6. 2 Bolometers - proto 2002 500 210 10. 5 5. 0 - - proto 2005 462 200 160 11. 0 8. 8 integrated processor for recognition. - - 2000 900 - 3 19. 1 - - - Smart. Finger Sweep 1 line. Non-active pixels on silicon. Discontinued in 2004. capacitive optical sweep -

Leti MEMS pressure - proto 2002 391 92 92 6. 0 - capacitive - LTT C 300 2003 313 192 128 15. 4 10. 3 - capacitive - LTT C 500 2003 500 236 192 11. 8 9. 6 - capacitive - LTT S 500 2004 Oct 500 200 16 10 0. 8 sweep-type LG-Philips optical TFT Finger. Talk proto 2000 300 240 256 20. 1 26. 8 Melfas capacitive - MFCS 1000 - 400 150 - 9. 6 - - Michigan univ. tactile - proto - 500 16 16 0. 8 - Optical TFT - proto 2003 feb 423 250 320 15. 0 19. 2 - capacitive TFT - proto 2003 Feb 423 250 320 15. 0 19. 2 - optical trans. - R&D 2003 - - - Mitsumi optical - SEFA 1 2005 jun 600 256 - 10. 8 - Proto shown May 2004. Nano. Ident photo-organic - proto 2005 250 256 - - (announced resolution is likely an error) NEC optical trans. Finger. Through 2002 Oct 800 480 540 15 18 Ligh. Tuning Mitsubishi SA 301 -10 backlight (approximative values)

Fingerprint sweep sensing

l l l l Fingerprint sweep (or swipe) sensors is a subcategory of fingerprint sensors, useful because of its lower cost production compared to static (or area) sensors. History of fingerprint sweep sensors 1997 May: Thomson-CSF (now Atmel) demonstrated the Finger. Chip FC 2 x 17, at the CTST'97. 1998 May: Thomson-CSF demonstrated the Finger. Chip FC 15 A 140. May: Seoul University submits a paper about a capacitance swipe sensor (published April '99). July: First prototype from Idex on its first sweep sensor. 1999 May: Sannaedle / Cecrop demonstrates My. Fin, a swipe optical reader. May: Kinetic Sciences demonstrates the KC-901 at the CTCT. 2000 May: Atmel unveils the Finger. Chip AT 77 C 101. May: Kinetic Sciences demonstrates a new version of their swipe optical sensor (K-1000? ).

l l l l l l l l l l 2001 April: Idex & STm announce the development of Smart. Finger. Sept: Fingerprint Cards announces the FCP 1030. Nov: Citizen & IBM shows the Watch. Pad, the first watch with a built-in fingerprint reader, the Finger. Chip. 2002 Feb: Fujitsu announces the MBF 300, and shows it at the CTST in May. Summer: Tima publishes about a sweep tactile sensor. Oct: I-Control promotes the ICS 3000 / PDS 3000 Nov: Authentec introduces the AES 2500. Nov: The HP i. PAQ h 5450 is the first PDA with a built-in fingerprint sensor, the Finger. Chip AT 77 C 101 from Atmel. Nov: STm unveils a Touch. Strip prototype at the COMDEX. 2003 Feb: Alps Electrics + Casio unveiled their "rolling-tube head" scanner. March: STm displays the Touch. Strip on the web. May: Digital Persona unveils the Firefly, a sweep optical fingerprint sensor using a roller. Jul: Sharp announces the Mebius Muramasa, the first Tablet PC with a build-in sweep fingerprint sensor, the Finger. Chip. Jul: Fujitsu announces the MBF 310. Sept: Melfas announces the MFCS 1000. Oct: YRP shows the Ubiquitous Communicator, a R&D study prototype, containing the Atrua sweep sensor. Nov: Elsafe installs the first safe with a sweep fingerprint reader, the Finger. Chip. 2004 Feb: I-Control becomes Atrua and promotes "Atrua Wings" (ATW 100). Feb: Atmel announces the AT 77 C 104, the Finger. Chip with integrated navigation. Feb: Atmel announces the colored Finger. Chip. Feb: The Fujitsu F 900 i cell phone contains the Authentec AES 2500. (Japan only) March: Upek becomes a spin-off from STm. March: Fingerprint Cards announces the FPC 1031 B. March: Validity unveils the VFS 101 (USB), VFS 131 (SPI) & FVS 161 (LPC) (RF Fingerprint imaging on flexible tape) March: Ritech announces the Bio. Slim. Disk i. Cool containing the Upek Touch. Strip. March: Trek announces Thumdrive Swipe containing the Upek Touch. Strip (to check). April: Fujitsu announces the LOOX T series notebooks (t 50 H & T 70 H) with the Authentec AES 2500. April: Motion Computing announces the M 1400 tablet PC with the Authentec AES 2500. April: MPC unveils the Transport X 3000 with the Upek Touch. Strip. May: The Fujitsu F 506 i cell phone contains the Upek Touch. Strip. (Japan only) June: The F 900 it is the same as F 900 i, but with a twist screen. June: The Gateway notebook 450 XL contains the Upek Touch. Strip. June: Authentec announces the AES 2510, a swipe sensor + navigation, available mid-June, $6.

l l l l l 2005 Jan: Bionopoly unveils. Bio-USB flash drive & Fingerprint Passcode Generator using the Atmel Finger. Chip. Feb: IBM announces a keyboard (and peripheral) with a swipe sensor. Feb: Atmel releases the Finger. Chip AT 77 C 105 Feb: Yulong announces the Coolpad 858 F GSM with the Atrua swipe fingerprint sensor. March: Authentec unveils the Entr壆ad 1510, a swipe sensor + navigation, $5. March: Sandisk unveils the Cruzer? Profile USB drive (using the Upek swipe sensor? ). March: IRevo introduces the Gateman MB 740 door lock using the Atmel Finger. Chip March: Atrua announces the ATW 200. No photo. March: G&D unveils the Star. Sign Bio Token containing the Finger. Chip sweep sensor.

l l l l l l l l l l March: The Fujitsu Stylistic ST 5022 Tablet PC with the Authentec swipe sensor. April: IBM unveils the Think. Pad X 41 with the Touch. Strip from Upek. April: LG releases the LG-LP 3550 cameraphone containing the Authentec AES 2500. April: Scandinavian Ecotechnologies presents a biometric card with an embedded swipe sensor likely from Fingerprint Cards. April: Toshiba introduces the Libretto U 100 with the Authentec AES 2500. April: Toshiba introduces the Portege R 200 = the Dynabook SS SX/190 with the Authentec AES 2500. April: Tychi unveils the Bio. Knob (door knob) April: MPC's Transport X 3100 with the sweep-type Upek Touch. Strip. May: Ritech unveils the i. DEA containing the Upek Touch. Strip. May: Ritech unveils the Bio. Mouse with the Upek Touch. Strip. May: Motion Computing announces the M 1600 tablet PC with the Authentec AES 2500. May: Fujitsu Life. Book S 6240, S 7020 & S 7021 / B 6000 with the Authentec swipe sensor. June: IBM unveils the Think. Pad X 41 Tablet with the Touch. Strip from Upek. June: Aratek Fingo Mouse / Fingo Reader / Fingo Lock using a swipe sensor from Authentec. June: NEC Versa C 250/M 350/P 550 with the Upek Touch. Strip sweep sensor June: La. Cie unveils the SAFE Mobile Hard Drive using a Upek Touch. Strip sensor. June: HP nx 6125 laptop with an Authentec 2501 swipe sensor. June: Mitsumi announces an optical sweep fingerprint sensor, the SEF-A 1 July: The Pantech & Curitel PT-K 1200 cellphone containing an Authentec swipe sensor is unveiled. July: Motion Computing unveils the LS 800 A 5 tablet PC with the Authentec AES 2501. July: Card Media announces the Storeguard with the AUthentec swipe sensor. July: MPC's Transport T 3100 with the Upek Touch. Strip. Aug: Fujitsu Life. Book P 1500 with the Authentec swipe sensor. Aug: More info about the Symwave capacitance sweep fingerprint sensor SW-6888 Aug: The Fujitsu Stylistic ST 5032 Tablet PC with the Authentec swipe sensor. Aug: Sony announces the Vaio BX series with the Upek swipe sensor. Aug: The Lenovo Think. Pad R 52 now offers a Upek fingerprint sensor (as an option). Sep: Itronix announces the Go. Book? VR-1 with the Upek swipe sensor. Sep: Lenovo unveils the Think. Pad Z 60 m & Z 60 t with the Upek swipe sensor. Sep: Toshiba announces the Tecra S 3 M 740 & M 780 Sep: Willcom unveil a cellphone proto using the Fujitsu swipe fingerprint sensor. Sep: HP released the HP i. PAQ hx 2790 with Windows Mobile 5. 0 with the Atmel Finger. Chip. Oct: Fujitsu Lifebook FMV P 8210, T 8210 & TB 12 Tablet PCs with the Authentec swipe sensor. Oct: Sony introduces the Vaio AX series (VGN-AX 570 G) with the Upek swipe sensor. Oct: Samsung unveils the SCH S 370 cellphone using the Authentec swipe sensor. Oct: Amoi announces the M 606, M 616 and A 717 notebook PCs with the Upek swipe sensor. Oct: Medion introduces the MD 96500 notebook PC with the Authentec Entre. Pad 2501 A swipe sensor.

Atmel l · Official homepage of the Finger. Chip: Atmel website See also the (local) Finger. Chip products page for more information.

l l Seoul University · A 600 -dpi Capacitive Fingerprint Sensor Chip and Image-Synthesis Technique (Lee & als, Seoul National University, 1998)

l l Idex · Homepage: Idex · (1998) IFF 120: first sweep active AC capacitance sensing prototype, started with Sintef. · (2001) Smart. Finger©: development with ST. IFF 120 Smart. Finger©

Sannaedle / Cecrop / Kinetic Sciences · Homepage: Cecrop/Sannaedle. · Homepage: Kinetic Sciences (KSI). · In 1999, Sannaedle (now Cecrop) offered a device called My. Fin. At the same time, KSI offered the KC-901, which was probably the same device. · In 2002, Cecrop was offering the CFS 2000, while KSI offered the K-1000. · In 2004, KSI is still displaying the device on their web site, while there is no more information about an optical sweep sensor on the Cecrop website.