Selection of Sensors
Suprema Inc. is supplying a variety of sensor selections with its customers, which is one of its unique strengths compared to its competitors. If you are seeking for the best eligible solution for your applications, please refer to the following sensor information or contact Suprema's sales team for details.

» Technology of different fingerprint sensors
› Optical Sensors
With optical sensors, the finger is placed on a plate and illuminated by LED light sources. Through a prism and a system of lenses, the image is projected on a CMOS image sensor. Using frame grabber techniques, the image is stored and ready for analysis.

› Thermal Sensors
Thermal sensors contain an array of temperature measurement pixels which make a distinction between the temperature of the skin (the ridges) and the temperature of the air (in the valleys). One dimension of this sensor can be fairly small since a temperature scan can be obtained by sweeping the finger over the sensor.

› Capacitive Sensors
Capacitive sensors use a difference between skin-sensor and air-sensor contact in terms of capacitive values. When a finger is placed on the sensor, an array of pixels measures the variation in capacity between the valleys and the ridges in the fingerprint.

› Electric Field Sensors
Electric Field sensor creates an electric field from a ring around the sensing area with which an array of pixels can measure variations in the electric field, caused by the ridges and valleys in the fingerprint. According to the manufacturer the variations are detected in the conductive layer of the skin, beneath the skin surface or epidermis.

» Advantages of Respective Sensors
For your better understanding, we believe that the advantages and specifications of the following sensors could help you out to choose suitable sensors for your applications.

Optical sensor has solid sensor surface and is comparatively inexpensive.
Thermal sensor has a small form factor and can be low priced for large volume.
Capacitive sensor has relatively hard coated surface as a solid state sensor.
Electric field sensor has a good performance for contaminated fingerprints.

» Specifications of Sensors

Sensor / Spec	OP	FC	TC1	TC2	FL
	Optical Sensor	Atmel's FingerChip	UPEK's TouchChip	UPEK's TouchChip	AuthenTec's AF-S2
Sensor Type	Optical	Swipe Type Thermal	Capacitive	Capacitive	E-Field
Resolution(dpi)	500	500	508	508	250
Sensing Area(mm)	16.0 × 19.0	14.2 × 0.4	12.8 × 18.0	10.4 × 14.4	13.0 × 13.0
Image Size(pixel)	280 × 320	280 × 8	256 × 360	208 × 288	128 × 128