Double-cavity structure capable of effectively reducing blind area of ultrasonic sensor and packaging process of double-cavity structure

Abstract

The invention discloses a double-cavity structure capable of effectively reducing a blind area of an ultrasonic sensor and a packaging process of the double-cavity structure, belongs to the technical field of ultrasonic sensors, and aims to solve the problems of poor product performance, low production efficiency, poor assembly consistency and relatively high production cost in the prior art. The packaging structure comprises an external packaging shell, an internal packaging shell, a chip and a substrate, the external packaging shell is bonded to the edge of the substrate, a first cavity is defined by the external packaging shell and the substrate, the chip is bonded to the substrate, and the chip is electrically connected with the substrate through a bonding alloy wire. The internal packaging shell is bonded on the substrate, the bottom edge of the internal packaging shell is located between the bottom edge of the external packaging shell and the edge of the chip, a second cavity is defined by the internal packaging shell and the substrate, and a circular sound outlet hole is formed in the top of the external packaging shell; square sound outlet holes are formed in the side walls of the internal packaging shell. The method is suitable for the distance measuring system based on the chip ultrasonic sensor.

Description

technical field [0001] The invention belongs to the technical field of ultrasonic sensors, and in particular relates to a dual-cavity structure and a packaging process for effectively reducing the blind area of ​​the ultrasonic sensor. Background technique [0002] Blind zone means that when ultrasonic waves are emitted, although the transmitted signal is only maintained for a very short period of time, after the application of the transmitted signal is stopped, there is still a certain residual vibration or trailing on the probe (due to the effect of mechanical inertia); during the blind zone time, the echo signal The strength of the signal is much smaller than that of the trailing signal, thus shielding the echo signal at close range. [0003] Currently commonly used methods to suppress blind spots: [0004] The first is to suppress the blind spot from the circuit, such as 1) external attenuation resistance; 2) reduce the ultrasonic transmission power; 3) time-varying gai...

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Problems solved by technology

[0006] The purpose of the present invention is to provide a dual-cavity structure and its packaging process that can effectively reduce the blind area of ​​an ultrasonic sensor, and solve the problems of poor performance, low production efficiency, poor assembly consistency, and high production costs in the prior art

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