Geometric structures for acoustic impedance matching and improved touch sensing and fingerprint imaging
US11715321B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 22, 2022 |
| Grant date | Aug 1, 2023 |
| Priority date | — |
| Expiry date | Apr 22, 2042 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10K11/02
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Improving the accuracy of ultrasonic touch sensing and fingerprint imaging using acoustic impedance matching is disclosed. Acoustic impedance mismatches between an ultrasonic transducer array and a sensing plate can be reduced to maximize energy transfer and minimize parasitic reflections. A reduction in acoustic impedance mismatches can be accomplished using (i) a composite epoxy having a higher acoustic impedance than epoxy alone, (ii) one or more matching layers having an acoustic impedance that is approximately the geometric mean of the acoustic impedance of the sensing plate and the acoustic impedance of the transducer array, (iii) pores or perforations in the sensing plate, or (iv) geometric structures formed in the sensing plate. In addition, parasitic reflections can be suppressed using an absorbent layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.