application

The application of the sensor described below shows the good effect of a product using a piezoelectric film sensor.

switch

The reliability of the general contact switch is reduced because its contacts are fouled by moisture and dust. The piezoelectric film switch is a single structure without such defects. The most challenging of all switching applications is the application on the bullet game machine.

A manufacturer of a bullet game machine used a piezoelectric film switch produced by the MSI company to replace the original transient flip switch on his machine. The switch is to press the piezoelectric film on the upper layer of the elastic steel sheet and install it as a cantilever at the end of the printed circuit board.

The digital piezoelectric film switch has the characteristics of a simple MOSFET circuit that does not consume the power of the power in a constant state. In response to a direct contact force, the piezoelectric film bullet instantaneously triggers the MOSFET circuit and generates an instantaneous "closed" maximum voltage of up to 50V. The output of this small contactless switch is very suitable for logical level switching. It is not like an ordinary contact switch that will appear corrosion, pitting and beating.

The company has failed more than tens of millions of tests on the switch. This switch solves the problem of the scale of the contact in this kind of game machine, which greatly reduces the cost of shutdown and cost. The simplification of the design is effective in the following applications, including:

Assembly line and shaft speed counter switch

Automatic process switch

Impact induction of machine batching products

Panel switch

Pedal switch

Door closing switch

Improve the cantilever beam carrying piezoelectric thin film to adjust

Switching sensitivity of different impact forces. Figure 51 shows

The structure of this digital switch.

Beam switch

A piezoelectric film switch can be used to measure the amplitude of an event.

Frequency and direction, and object detection and recognition, counting, wake up

In the application of closing and bidirectional encoding, the structure of the beam type switch is shown.

Figure 52.

It is noted that the piezoelectric film element is laminated on one side of the thicker substrate, and the pressure layer on the other side is thinner, so that the axis is not on the piezoelectric film element. Thus, when the stress is downward, the full tensile strain is formed on the piezoelectric film, and the compressive strain is formed when the stress is upward. If the axis is located at the center of the piezoelectric membrane, that is to say, the thickness of the two sides of the press layer is the same, no matter upward or downward deformation, the upper half of the piezoelectric film will bear the reverse stress in the lower part, so the generated signal is cancelled.

The beam switch is applied to the shaft speed counter in the natural gas pressure meter or the number counter in the electronic public instrument. The beam switch does not require an external power supply, so the natural gas meter is quite safe and sparkless. Application examples in other ways: Softball target ball test, shooting the basket in the sense counter, and soft doll face kiss and amused switch (sensor sewing doll in addition), vending machines, coin sensor etc..

Fast switch

The piezoelectric materials have no response to pure DC, for low frequency events

Such as 0.0001Hz, usually can not be detected by a piezoelectric film.

When the application requires a direct current response, a piezoelectric film can be matched.

A touchable roof cover produces a high pressure pulse.

When the button device is touched, the piezoelectric film quickly strain, 1

In the 1M Omega circuit shown in Figure 53, a 10V is produced.

Pulse. This concept is especially suitable for wake-up switch, circuit

It is always in the non working state, and only when the switch is touched, the piezoelectric pulse will connect the circuit. Battery parking meter is an example of applying a piezoelectric fast switch, because the battery life is very important.

Collision sensor

Hit type printer

High speed impact printer requires very precise printhead timing. The high-speed steel belt with character is located just before printing hammer, and it must strike. Any advance or lag action of a print hammer can only lead to a print misplacement.

The piezoelectric film sensor strip is installed in the press plate of the printer to monitor the strike time and the striking force of the print head and to signal to the controller. The timing of the actuator is automatically adjusted according to a small change in the timing of the print head. The high speed operation of the steel strip (300 inches / sec) requires a very fast response switch. The original strike switch is damaged very quickly because of the big strike force of the printing head. Piezoelectric thin film switches have worked for more than five years in this application.

Sports score

A piezoelectric film sensor can be used to measure the time, position (precision) and force of a strike, and these parameters are needed in several sports scoring. The 90mph throw has an instantaneous power of about 50000 watts, the challenge of which is the robustness of the target and no strong tremor in the design.

Second is the application of electronic target scoring disc, which is composed of a piezoelectric film monitoring many hit areas, to achieve electronic scoring.

Musical Instruments

The large number of applications of electronic technology on musical instruments brings special problems to drum and piano. Piezoelectric film striking elements can meet the requirements of dynamic range and frequency response of drum trigger and piano keyboard. The piezoelectric diaphragm with a pedal switch, to achieve a bass drum, snare drum bottom trigger sound and India natives. The piezoelectric film strike switch is very sensitive and can faithfully reproduce the style of the drummer and the pianist. In the electronic organ, the dynamic response range and time constant of the piezoelectric film switch are very similar to the piano.