Mechanical design basis

The output energy is proportional to the stress caused by a piezoelectric film. The thickness of the film can also be determined from the mechanical strength in order to obtain the optimal signal to select the proper film thickness. Thicker film has higher voltage but less capacitance. Therefore, thinner film and flexible inert material (e.g. polyester, see LDT1~028K) may be better than single thick film. Any membrane area without stress is a capacitive load on the effective working area, and the smaller the better it is if needed.

Most of the metal layers are easy to rust, especially when transportation, thin coating or laminating is used to maintain the surface quality. In laminating and assembly, acrylic gum is often used to synthesize rubber resin, epoxy resin and cyanoacrylate. In some designs, the outer metal layer or the conductive substrate is used as the electrode, and the unmetallized piezoelectric film is used to its own advantages. The outer metal layer can directly contact the unmetallized film to collect the charge, or, in AC signal application, the capacitive coupling can be achieved through thin tape or epoxy resin layer. The shape of the electrode is particularly useful for determining the specific effective working area on the whole continuous membrane material, and also for leaving the blank blank space in the cutting part when cutting the components. The design of the upper and lower electrode leads can prevent the unexpected problems of the piezoelectric film caused by the influence of the lead contact. It is also easy to take the low cost and penetrating lead method (the pressing terminal or the hollow rivet).

Mechanical and electrical comprehensive design basis

The capacitive nature of piezoelectric film determines its vulnerability to electromagnetic interference. As the output signal level decreases, this becomes more important. But when the output signal is very high or the piezoelectric film is driven under unimportant conditions, the electromagnetic interference can not be considered. The interference of AC power supply may be a problem for unshielded devices. Another potential problem is that when an electrode is being driven and the other is receiving a vibration signal, it is necessary to avoid "crosstalk".

In the case of the use of a