Self-Capacitive Transparent Fingerprint Sensor

Nano Materials | TFT | Capacitive Pressure Sensing | Human Skin Properties | Literature Review

Objective

Design tactile, transparent sensor that detects variations in surface geometry as small as 100µm to enable fingerprint detection for authentication in a consumer device.

Engineering Requirement

Metric

Desired Value

Estimated Value
R1. Sensitivity Ratio of paracitic capacitance to ridge-valley capacitance Less than 1000 80
R2. Resolution Pixels per inch (PPI) 300 to 700 PPI 508 PPI
R3. Size Component and sensor dimentions Pixel: 36x36 μm to 84x84 μm
Array: 6 mm x 6 mm
Array: 63x63 to 130x130 pixels 		Pixel: 50μm x 50μm
Array: 6mm x 6mm
Array: 100x100 pixels
R4. Temperature Range Temperature operation range -40 to 80 degrees celcius -45 to 150 degrees celcius
R5. Cost CAD Less than 34 CAD per unit 14.35 CAD

Result

Designed weatherproof, biocompatible, self-capacitive, transparent, 504 PPI fingerprint sensor with a 100 x 100 sensor pixel array. Simulations of sensor showed noise suppression aligning with or surpassing currently available sensor options.

Sketch

Sketch Sketch