Piezoelectric Tuning Fork Electrode Layout for Rectilinear Field Detection
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Solution Overview
Problem
Existing angular velocity transducers with piezoelectric tuning forks face challenges in optimal detection electrode arrangement, leading to non-rectilinear electrical field paths and complex manufacturing methods, which result in suboptimal measurement and increased size for miniature applications.
Innovation Solution
The detection electrodes are arranged in a cross-shaped section with protruding parts on the detection leg, allowing for a simple manufacturing method and a substantially rectilinear electrical path, along with mechanical uncoupling at the base to reduce size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detection electrodes are arranged on lateral faces of the tuning fork, then the electrical field can be detected, but the electrical path becomes non-rectilinear causing field line loss and suboptimal measurement
Solution Approach 1:
The detection leg is divided into two separate legs, with detection electrodes arranged on each leg. This segmentation allows the electrical field to be detected along a rectilinear path through each leg independently, preventing field line loss while maintaining detection capability.
Solution Approach 2:
The detection electrodes are arranged in a plane perpendicular to the excitation vibration plane, creating a three-dimensional detection configuration. This dimensional arrangement ensures that the electrical field lines follow a rectilinear path through the detection leg, optimizing measurement while reducing energy loss.
2Measurement precision
If the two pairs of detection electrodes are arranged as shown in FIG. 1c, then the measurement can be optimized, but the manufacturing method becomes complex and difficult to control
Solution Approach 1:
The tuning fork is segmented into two separate detection legs instead of placing electrodes on the lateral faces of a single leg. This segmentation simplifies the manufacturing process by allowing standard electrode deposition techniques to be applied to each leg independently, avoiding the complex separation requirements of lateral face electrodes.
Solution Approach 2:
Instead of placing detection electrodes on the lateral faces of the tuning fork leg as in conventional designs, the invention inverts the arrangement by placing them on separate legs perpendicular to the excitation plane. This inverted configuration maintains measurement optimization while enabling simpler manufacturing.
3Volume of moving object
If the tuning fork size is reduced for miniature applications, then the device becomes more compact, but the detection electrode arrangement becomes more difficult to implement
Solution Approach 1:
The detection function is segmented across two separate legs rather than requiring complex electrode patterns on a single leg. This segmentation allows for scalable miniaturization, as each leg can be independently sized and manufactured, making the overall device more compact while maintaining ease of manufacture.
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 arrangement enhances the detection of the electrical field while simplifying the manufacturing process and miniaturizing the transducer, resulting in improved measurement accuracy and reduced size.
Implementation Method 1
the piezoelectric quartz of tuning fork 1 into an electric signal which is detected by the tuning fork detection electrodes 7a-7b, 8a-8b
Implementation Method 2
to which an alternating electric signal is applied at the resonant frequency of the tuning fork in its main plane
Implementation Method 3
an angular rotational movement of tuning fork 1 about its longitudinal axis 10 generates a Coriolis force perpendicular to the velocity of the excited leg and to rotational axis 10
Data Source
AI summary
A transducer for measuring an angular velocity formed by a single piezoelectric tuning fork (21) that rotates at the angular velocity. The tuning fork has a detection leg (24) which has a cross-shaped section including two top lateral faces (33, 34) and two bottom lateral faces (37, 38) separated by protruding parts (41, 42) projecting with respect to the faces. The detection leg has detecting electrodes which are arranged such that the electrical field between electrodes is substantially rectilinear through the detection leg.