Ultrasonic Sensor Module Assembly for Document Verification
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Solution Overview
Problem
The production of ultrasonic sensors for detecting and examining documents of value is challenging due to the difficulty in handling piezoelectric transducers and the need for precise connections of flexible pigtails to conductor tracks on printed circuit boards, which requires careful temperature management and is not easily scalable.
Innovation Solution
An ultrasonic sensor module with a piezoelectric ultrasonic transducer and an assembly module that includes conductor tracks for easy mounting and soldering onto a connection carrier, allowing for the alignment and secure attachment of the transducer module, even with multiple transducers, facilitating the production of ultrasonic sensors with improved alignment and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flexible connecting leads are used to connect piezoelectric transducers to conductor tracks, then the transducers can be electrically connected without interfering with vibration, but the manufacturing process becomes complex and difficult to scale
Solution Approach 1:
The device is divided into modular components: a mounting module that holds the piezoelectric transducer, a connection carrier with conductor tracks, and flexible connecting leads. This segmentation allows each component to be optimized independently - the mounting module provides mechanical support and alignment, the connection carrier provides electrical connectivity, and the flexible leads provide vibration-isolated electrical connection. This modular approach simplifies manufacturing by enabling separate assembly and testing of components before final integration.
Solution Approach 2:
The flexible connecting leads serve as intermediaries between the piezoelectric transducer and the rigid conductor tracks on the connection carrier. These leads act as a mediator that accommodates the conflicting requirements of electrical connectivity and vibration isolation. The flexibility of the leads allows them to bend and move with the transducer during vibration while maintaining electrical contact, thereby resolving the contradiction between reliable electrical connection and manufacturing complexity.
2Reliability
If piezoelectric transducers are handled during sensor manufacturing, then ultrasonic transduction can be achieved, but temperature control is critical as they can only withstand up to 80-90°C
Solution Approach 1:
The mounting module is prepared in advance with pre-positioned conductor tracks and connection points before the piezoelectric transducer is attached. This preliminary preparation allows the transducer to be mounted quickly and securely without prolonged exposure to high temperatures during assembly. The connection carrier is also pre-configured with conductor tracks that align with the transducer's electrical contacts, enabling rapid connection that minimizes thermal exposure and ensures proper electrical connectivity from the start.
3Ease of manufacture
If rigid connecting pins are used for ultrasonic transducers, then manufacturing would be simpler, but the pins would interfere with the vibration of the piezoelectric element
Solution Approach 1:
The connecting leads exhibit different mechanical properties at different locations: they are rigid near the connection points to ensure stable electrical contact with both the transducer and the conductor tracks, but become flexible along their length to allow vibration of the piezoelectric element without interference. This gradient in rigidity - rigid at connection points, flexible in the middle section - allows the connecting structure to simultaneously provide mechanical stability for electrical connection and freedom of movement for ultrasonic vibration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution simplifies the manufacturing process of ultrasonic sensors by enabling easy assembly and alignment of transducers, ensuring reliable electrical connections and mechanical stability, while allowing for the production of sensors that can detect document edges, double prints, and ultrasonic properties with increased accuracy.
Implementation Method 1
piezoelectric ultrasonic transducer with electrical connecting leads, wherein the mounting module has conductor tracks that are electrically connected to the connecting leads of the at least one ultrasonic transducer
Implementation Method 2
the contact surfaces and the complementary contact surfaces can each be soldered together
Data Source
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AI summary
The invention relates to an ultrasonic transducer module for an ultrasonic sensor for detecting and/or examining valuable documents, comprising at least one piezoelectric ultrasonic transducer having electrical connecting wires and an installation module for retaining the at least one ultrasonic transducer in order to install the ultrasonic transducer on a connection carrier, wherein the installation module has conducting tracks, which are electrically connected to the connecting wires of the at least one ultrasonic transducer and which have contact surfaces, which are designed in such a way that the ultrasonic transducer module can be placed onto a surface of the connection carrier, on which contact surfaces complementary to the contact surfaces are located, in order to install the ultrasonic transducer module, and the complementary contact surfaces can be soldered to each other.