JPS5830394Y2 - piezoelectric microphone - Google Patents

Description

[Detailed description of the invention] This invention relates to a piezoelectric microphone mainly used for measuring blood pressure and heart sounds in the human body, and the intended purpose is to have excellent flexibility and mechanical strength, and a high shielding effect. To provide a piezoelectric microphone.

The drawings will be explained below. In FIG. 1, reference numeral 1 indicates a center electrode 1b provided on the upper surface of a thin plate of a flexible insulating material such as polyimide resin in an area excluding the outer peripheral portion.
and an extraction electrode 1b' extending from this toward one end 1a' of the insulating thin plate, and an outer peripheral electrode 1C surrounding these through a predetermined insulating gap and provided at the periphery of the insulating thin plate 1a, Shield electrode 1 provided on the entire bottom surface
d, each of the electrodes 1 b, 1
b', IC, and 1d are printed with copper foil or the like as is known in the art.

2 is a flexible piezoelectric element that is brought into contact with the center electrode 1b on the upper surface of the printed circuit board 1, and is made of a polymeric piezoelectric material such as polyvinynodenene fluoride, natural or synthetic rubber, or synthetic resin, as is known in the art. A polymer composite piezoelectric material made by uniformly dispersing piezoelectric ceramic powder is stretched or rolled into a film or sheet, and the center electrode 1b controls one electrode of the piezoelectric element.

Reference numeral 3 denotes an electrode member that controls the other electrode of the piezoelectric element, which is covered so as to be in contact with the upper surface of the flexible piezoelectric element 2 and the outer peripheral electrode 1C of the printed circuit board, and is made of an elastomer such as conductive rubber or conductive resin.

The printed circuit board 1, piezoelectric element 2, and electrode member 3 are integrally bonded by thermocompression bonding, simultaneous vulcanization, or other suitable bonding means.

After bonding, for example, 1
It is preferable to perform the polarization treatment by heating a DC high voltage voltage of about 00 KV/an to 50 to 150° C. and applying it for several minutes to several tens of minutes, since there is no deterioration in polarization due to heat such as pressure bonding or vulcanization.

Thereafter, the signal carrying lead wire 4 and the grounding lead wire 4' are connected, respectively.

A shield electrode 1d provided on the lower surface of the printed circuit board 1 is grounded to an outer peripheral electrode 1C on the upper surface through a conductive through hole 1e.

Moreover, this outer peripheral electrode 1C is composed of a center electrode 1d and an extraction electrode 1b'.
Because it is located so as to surround the shield, it has the effect of further enhancing the shielding effect.

Next, FIG. 2 shows another embodiment of the present invention, in which the center electrode 1 of a printed circuit board has a center electrode 1b, an extraction electrode 1b', and an outer peripheral electrode 1C on the upper surface of a flexible thin insulating plate 1a.
An electrode member 3 made of a conductive elastomer is coated on the bottom surface of the printed circuit board 1 so that the lower surface of the flexible piezoelectric element 2 is brought into contact with the upper surface of the piezoelectric element 2 and the outer peripheral electrode, and the lower surface of the printed circuit board 1 is covered with
In place of the metal foil in the embodiment shown in FIG. 1, a shield electrode 5 made of the same conductive elastomer as the electrode member 3 is coated and bonded together. The flexibility can be increased and the flexibility of the entire structure can be made sufficiently good.

The piezoelectric microphone of the present invention has the above-mentioned configuration, and since each component such as the printed circuit board, piezoelectric element, and electrode member is made of flexible materials, the piezoelectric microphone as a whole is thin and exhibits excellent flexibility. Because of its structure, when measuring blood pressure and heart sounds, it can be worn in close contact with the skin of the human body without causing the subject to feel a foreign body sensation or pain, and the printed circuit board reinforces the piezoelectric element to prevent mechanical damage. Due to its increased strength, the piezoelectric element will not be damaged by stress such as tension or shearing during handling, making it extremely easy to handle.Furthermore, the shield electrode provides a shielding effect, suppressing noise caused by electrostatic induction. However, it has many effects such as being able to accurately and faithfully measure blood pressure and heart sounds.

[Brief explanation of drawings]

FIG. 1 shows a piezoelectric microphone according to an embodiment of the present invention, in which A is a perspective view, B is a sectional view taken along line E in FIG. A, and C is an exploded perspective view. Figure 2 relates to another embodiment of the present invention, where A is a perspective view and B is a perspective view.
Figure C is a cross-sectional view taken along the Rolo line, and C is an exploded perspective view. DESCRIPTION OF SYMBOLS 1... Printed circuit board, 1a... Flexible insulating thin plate, 1b... Center electrode, 1d, 5...
...shield electrode, 1b'...extraction electrode, 1
C: outer peripheral electrode, 2: flexible piezoelectric element, 3: electrode member.

Claims (1)

[Scope of utility model registration request] A shield electrode is provided on the lower surface of the printed circuit board, which has a center electrode on the top surface of a flexible thin insulating plate, an extraction electrode extending from the thin insulating plate to one end, and an outer peripheral electrode surrounding the center electrode and the extraction electrode. A piezoelectric microphone characterized in that a flexible piezoelectric element is brought into contact with an electrode, and an electrode member made of a conductive elastomer is coated so as to be in contact with the upper surface of the piezoelectric element and the outer circumferential electrode of a printed circuit board, and the piezoelectric microphone is integrally bonded to the electrode. .