Ultrasonic-based acoustic impedance calibration method, ultrasonic sensor, ultrasonic fingerprint identification module and electronic equipment

Abstract

The invention provides an ultrasonic-based acoustic impedance calibration method. The comprises the steps that S1, an ultrasonic sensor sends out an ultrasonic transmitting signal; S2, the ultrasonicsensor receives an ultrasonic feedback signal; S3, the ultrasonic transmitting signal and the ultrasonic feedback signal analyzed to obtain an ultrasonic transmission characteristic parameter; S4, a pre-stored ultrasonic transmission characteristic parameter is obtained; and S5; the ultrasonic transmission characteristic parameter obtained in the S3 is compared with that in the S4 to determine whether the acoustic impedance of the ultrasonic transmission path is changed. If YES, calibration can be carried out in real time, and the sensing precision of the ultrasonic sensor is ensured. The ultrasonic sensor, an ultrasonic fingerprint identification module and electronic equipment provided by the invention have the same advantages.

Description

【Technical field】 [0001] The invention relates to the field of ultrasonic waves, in particular to an ultrasonic-based acoustic impedance calibration method, an ultrasonic sensor, an ultrasonic fingerprint identification module and electronic equipment. 【Background technique】 [0002] Ultrasonic sensors are sensors that convert ultrasonic signals into other energy signals, usually electrical signals. Ultrasound has the advantages of high frequency, short wavelength, small diffraction phenomenon, and strong penetrating power, so it is widely used in industry, national defense, biomedicine, etc. [0003] In recent years, ultrasonic sensors have begun to be used in consumer electronics products, such as fingerprint recognition of mobile phones. Ultrasonic sensors, as a fingerprint recognition module, are mounted on mobile phones to detect user's fingerprint information. Such as figure 1 As shown, it is a schematic diagram of the structure of an ultrasonic sensor applied to an ...

AI Technical Summary

Problems solved by technology

When the user is operating, the ultrasonic waves emitted by the ultrasonic sensor 1 need to pass through the adhesive layer 8 and the protective film 6 to reach the user's fingers. Due to the introduction of two different media, it will change the acoustic impedance of the ultrasonic transmission path. Ultrasonic waves produce signal attenuation, and the materials of the protective film 6 and the adhesive layer 8 are different, and the acoustic impedance of the ultrasonic transmission path is also inconsistent. It is difficult for the ultrasonic sensor to match a large number of mobile phones and protective films. Sensitivity drops

Images