US Patent Application 18331867. GEOMETRIC STRUCTURES FOR ACOUSTIC IMPEDANCE MATCHING AND IMPROVED TOUCH SENSING AND FINGERPRINT IMAGING simplified abstract

GEOMETRIC STRUCTURES FOR ACOUSTIC IMPEDANCE MATCHING AND IMPROVED TOUCH SENSING AND FINGERPRINT IMAGING

Organization Name

Apple Inc.

Inventor(s)

Daniel J. Hiemstra of San Francisco CA (US)

George Ho Yin Mak of Fremont CA (US)

Ehsan Khajeh of Los Gatos CA (US)

Hoishun Li of Sunnyvale CA (US)

GEOMETRIC STRUCTURES FOR ACOUSTIC IMPEDANCE MATCHING AND IMPROVED TOUCH SENSING AND FINGERPRINT IMAGING - A simplified explanation of the abstract

This abstract first appeared for US patent application 18331867 titled 'GEOMETRIC STRUCTURES FOR ACOUSTIC IMPEDANCE MATCHING AND IMPROVED TOUCH SENSING AND FINGERPRINT IMAGING

Simplified Explanation

- The patent application discusses a method for improving the accuracy of ultrasonic touch sensing and fingerprint imaging. - It focuses on reducing acoustic impedance mismatches between an ultrasonic transducer array and a sensing plate. - The goal is to maximize energy transfer and minimize parasitic reflections. - Several techniques are proposed to achieve this:

 * Using a composite epoxy with a higher acoustic impedance than regular epoxy.
 * Adding one or more matching layers with an acoustic impedance that is the geometric mean of the sensing plate and transducer array.
 * Introducing pores or perforations in the sensing plate.
 * Creating geometric structures in the sensing plate.

- Additionally, the application suggests using an absorbent layer to suppress parasitic reflections.

Original Abstract Submitted

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.