Biometric sensor with delay layer
A biometric scanner is described and claimed. The scanner has a platen, an ultrasonic plane wave generator, an ultrasonic detector, and a delay layer residing between the generator and the detector.
1. A biometric scanner, comprising:
a platen;
an ultrasonic plane wave generator;
an ultrasonic detector; and
a low-attenuation-plastic delay layer residing between the generator and the detector.
2. The scanner of claim 1 , wherein the ultrasonic detector includes an array of individually addressable elements.
3. The scanner of claim 2 , wherein the array of individually addressable elements is a semiconductor array.
4. The scanner of claim 2 , wherein the array of individually addressable elements is a TFT array.
5. The scanner of claim 2 , wherein the array of individually addressable elements is fixed to an insulating substrate.
6. The scanner of claim 2 , wherein the ultrasonic detector includes an insulating substrate.
7. The scanner of claim 6 , wherein the insulating substrate is plastic.
8. The scanner of claim 6 , wherein the insulating substrate is a ceramic.
9. The scanner of claim 8 , wherein the ceramic is glass.
10. The scanner of claim 1 , wherein the detector includes a hydrophone array.
11. The scanner of claim 10 , wherein the hydrophone array has a first electrode and a plurality of second electrodes, wherein the second electrodes are positioned between the first electrode and the array of individually addressable elements.
12. The scanner of claim 11 , wherein the hydrophone array includes a piezoelectric film residing between the first electrode and the plurality of second electrodes.
13. The scanner of claim 12 , wherein the piezoelectric film is PVDF.
14. The scanner of claim 12 , wherein the piezoelectric film is PVDF-TrFE copolymer.
15. The scanner of claim 12 , wherein the piezoelectric film is PVDF-TFE copolymer.
16. The scanner of claim 12 , wherein the piezoelectric film is a polymeric or ceramic film exhibiting ferroelectric or piezoelectric properties.
17. The scanner of claim 1 , further comprising control electronics connected to the generator and to the detector, the control electronics being able to manage timing of a generated energy pulse, and sensing of reflected energy resulting from the generated pulse, the reflected energy being reflected by an object residing on the platen.
18. The scanner of claim 1 , wherein at least one of the platen and the delay layer is a polystyrene resin.
19. The scanner of claim 18 , wherein the polystyrene resin is Cross Linked Polystyrene (“XLPS”).
20. The scanner of claim 18 , wherein the polystyrene resin is General Purpose Polystyrene (“GPPS”).
21. The scanner of claim 1 , wherein at least one of the platen and delay layer is a PMMA resin.
22. The scanner of claim 1 , wherein the delay layer is a plastic material.
23. The scanner of claim 1 , wherein the detector is an array of semiconductors.
24. The scanner of claim 23 , wherein the semiconductors are CMOS transistors.
25. The scanner of claim 23 , wherein the semiconductors are charge coupled devices.