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Touch fingerprint sensor based on sensor cell isolation technique with pseudo direct signaling

   | 02. Mai 2018

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Figure 1

Fingerprint sensor cell (A) circuit for isolation scheme of sensor cell (B) implemented layout of the sensor cell.
Fingerprint sensor cell (A) circuit for isolation scheme of sensor cell (B) implemented layout of the sensor cell.

Figure 2

Top view layout of the 25 fingerprint sensor cell array with fingerprint sensor with isolation sensor cell scheme, an evaluation sensor cell, isolation sensor cells, and transmission sensor cells.
Top view layout of the 25 fingerprint sensor cell array with fingerprint sensor with isolation sensor cell scheme, an evaluation sensor cell, isolation sensor cells, and transmission sensor cells.

Figure 3

The implemented fingerprint sensor with pipelin scan driver hitecture.
The implemented fingerprint sensor with pipelin scan driver hitecture.

Figure 4

The timing diagram and output voltage characteristics of the pipelined scan driver for the fingerprint sensor.
The timing diagram and output voltage characteristics of the pipelined scan driver for the fingerprint sensor.

Figure 5

The implemented full chip layout of the 96 × 96 fingerprint sensor with standard CMOS 0.25 μm technology.
The implemented full chip layout of the 96 × 96 fingerprint sensor with standard CMOS 0.25 μm technology.

Figure 6

Fabricated fingerprint sensor (A) die photo, (B) LGA package front and back.
Fabricated fingerprint sensor (A) die photo, (B) LGA package front and back.

Figure 7

Fingerprint sensor test evaluation environment.
Fingerprint sensor test evaluation environment.

Figure 8

PC interface program.
PC interface program.

Figure 9

Captured fingerprint image (A) original (B) histogram equalization.
Captured fingerprint image (A) original (B) histogram equalization.

Figure 10

Wiener filtered fingerprint image (A) local size of 3 × 3, (B) local size of 5 × 5.
Wiener filtered fingerprint image (A) local size of 3 × 3, (B) local size of 5 × 5.

Figure 11

Weight of 2D Gaussian filter (A) 3 × 3, (B) 5 × 5.
Weight of 2D Gaussian filter (A) 3 × 3, (B) 5 × 5.

Figure 12

2D Gaussian filtered fingerprint images (A) local size of 3 × 3, (B) local size of 5 × 5.
2D Gaussian filtered fingerprint images (A) local size of 3 × 3, (B) local size of 5 × 5.

Figure 13

Weight estimation of 2D FIR filter for 50 µm-thick molded fingerprint sensor.
Weight estimation of 2D FIR filter for 50 µm-thick molded fingerprint sensor.

Figure 14

Weight of 2D FIR filter (A) 3 × 3, (B) 5 × 5.
Weight of 2D FIR filter (A) 3 × 3, (B) 5 × 5.

Figure 15

2D FIR filtered fingerprint images (A) 3 × 3, (B) 5 × 5.
2D FIR filtered fingerprint images (A) 3 × 3, (B) 5 × 5.

Figure 16

The matching performance of the fingerprint sensor (FAR vs. FRR).
The matching performance of the fingerprint sensor (FAR vs. FRR).

Performance summary and comparisons.

Parameter This work Ref. Hassan and Kim (2018) Ref. Shimamura et al. (2010) Ref. Jung et al. (2005)
Technology 0.25 µm 0.13 µm 0.5 µm 0.35 µm
Type of sensor Capacitive Capacitive Capacitive Capacitive
Supply voltage 1.8~2.5 V 1.5 V 3.3 V 3 V
Molding thickness 80 µm
Operating frequency 10 MHz (readout 30 MHz) 1 MHz 40 MHz
Power dissipation <3 mA 7.5 mA (25 mW) 7.5 mA (25 mW)
Image capture timea <20 ms 0.2 ms 20 ms
Array size 96 × 96 20 × 16 224 × 256 160 × 192
Image resolution 508 ppi 282 ppi 508 ppi 423 ppi
FRR@FAR = 10−4 2.2%
eISSN:
1178-5608
Sprache:
Englisch
Zeitrahmen der Veröffentlichung:
Volume Open
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Technik, Einführungen und Gesamtdarstellungen, andere