JPS5813317Y2 - Miyakuhakukei - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pulse meter using a polymer piezoelectric film.

Pulse meters are important as one type of medical equipment, and in particular, pulse meters with good responsiveness to pulses are desired.

However, conventional pulse monitors, such as those using lead silicate or PZT ceramic sensors, have a rate of 10
Only an output voltage of about 0 μV to 200 μV can be obtained, and if there is an influence of noise or the like, it may not be possible to accurately determine the pulse rate.

In order to improve the responsiveness to such pulses, it is necessary to: ■ improve the sensitivity of the sensor, that is, the conversion efficiency of the mechanical to electrical conversion system, and ■ reduce the loss in this conversion system, especially between the sensor and the human body. It is important to eliminate loss at the contact points.

The present invention takes the above points (1) and (2) into account and attempts to provide a pulse meter with good responsiveness to pulses.

The structural features of the present invention correspond to the above points ① and ②, and one is that a piezoelectric element mainly made of a polymeric piezoelectric film is used as a sensor, and the other is that a pulse rate monitor is used as a sensor. In order to improve the adhesion between the main body and the human body, a flexible member such as urethane foam is loaded on the back side of the piezoelectric element.

Here, the above-mentioned polymeric piezoelectric film refers to a polymeric film such as poly(7-isovinyzoline) or polyfluorinated ethylene propylene that has piezoelectric properties (when subjected to mechanical strain, the charge balance is disrupted and an electric field is generated). It has the following characteristics.

As a method for imparting piezoelectricity, a method is used in which the polymer is stretched and then polarized at a temperature of about 100 to 200'C.

Polarized polymer piezoelectric film has a small piezoelectric constant but an extremely large voltage constant compared to PZT-based ceramics, etc. Also, since it is a polymer material, it has particularly excellent flexibility. ing.

On the other hand, a flexible elastic member such as the above-mentioned urethane foam (having an elasticity comparable to or less than that of the human body) is preferable.

) improves the adhesion of the piezoelectric element to the human body and concentrates the force caused by the pulse at one point on the piezoelectric element.

For this reason, in the pulse meter of the present invention, there is less loss at the contact point between the sensor and the human body, and the sensor itself has good sensitivity, resulting in an output that responds to the pulse. A large value (for example, about 20 mV) can be obtained as a voltage.

Hereinafter, embodiments of the present invention shown in the figures will be described.

FIG. 1 is a side sectional view showing an embodiment of the pulse meter of the present invention.

In the figure, 1 is a film-like piezoelectric element (sensor) mainly made of a polymer piezoelectric film such as polyvinylidene fluoride. Moreover, the surface on the side of the thin film electrode 3b, which is the surface in contact with the human body, is covered with a protective film 3c.
(made of polymer film or metal foil).

Aluminum, copper, etc. can be used as the material for the thin film electrodes 3a and 3b, and a vacuum evaporation method or a method of pasting foil can be used to obtain the thin film.

Reference numeral 4 denotes a shield case made of copper, aluminum, etc., on the lower surface of which the piezoelectric element 1 is constructed and attached with a flexible elastic body 5 such as urethane foam interposed therebetween.

Therefore, the shield case 4 has a shielding function to eliminate electrical influence from the outside to the piezoelectric element 1, and a function as a support body for mounting the piezoelectric element 1.

In addition, the flexible elastic body 5, which is the essential part of the present invention, is in close contact with the piezoelectric element 1 and constantly applies tension to the polymeric piezoelectric film 2 to press the button, thereby improving the sensitivity of the sensor. .

6 is a shielding case 4 for the film-like piezoelectric element 1;
For mounting, a frame (a ring made of metal or plastic, etc.) is used to press the entire circumference of the piezoelectric element 10 against the shield case 4.

In this case, the thin film electrode 3a on the top surface of the piezoelectric element 1,
An insulator frame I is interposed between the shield case 4 and the thin film electrode 3a on the upper surface and the thin film electrode 3b on the lower surface to ensure electrical insulation.

Therefore, the lead wire 8a from the thin film electrode 3a on the upper surface is drawn out through the hole 9 penetrating the shield case 4 and the insulator frame I, and the lead wire 8b from the thin film electrode 3b on the lower surface is drawn out from the shield case 4. pulled out directly from the top of the

Note that the hole 10 made in the shield case 4 is a hole for venting air.

Now, when measuring the pulse using the pulse meter as described above, press the protective film 30 surface against the measurement part, and while it is pressed, place the main body of the pulse meter such as the shield case 4 on the rubber pan) W. It is fixed to the human body.

Then, an output signal corresponding to the pulse is sent to the lead wire 8a,
Catch it through 8b.

As an output signal (voltage), a very high value of, for example, about 20 mV can be obtained.

In this case, it is natural to be able to amplify this output signal, record it as a waveform on a recorder, convert it into a pulse rate for 91 minutes using a predetermined electrical circuit, and display it. It is.

In the above embodiment, the piezoelectric element 1 is made up of one polymeric piezoelectric film 2. It may also be configured by using piezoelectric films 21 and 22.

In that case, the two polymer piezoelectric films 21 and 22 are
Their polarization directions are made to face each other, and they are bonded together with a conductive film 31 interposed therebetween.

Then, this conductive film 31 is connected to one output electrode and the two on the outside of the bed.
The conductive films 32 and 33 on the surface are short-circuited and used as the other output electrode.

In such a case, the output voltage will be much higher.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing one embodiment of the pulse meter of the present invention, and FIG. 2 is a side sectional view showing another example of a piezoelectric element that is a component of the pulse meter. 1,...Piezoelectric element, 2...Polymer piezoelectric film, 3as3b...Thin film electrode, 3c...
... Protective film, 4 ... Shield case (support body), 5 ... Flexible elastic body, 6 ...
Mounting is on the surrounding frame, T...Insulator frame, 8 a, 8
b-Lead wire, 9, 1 0-----hole, 21
゜22...Polymer piezoelectric film, 31.32
, 33... conductive film.

Claims (1)

[Scope of utility model registration request] A film-like piezoelectric element mainly composed of a polymeric piezoelectric film is installed on one surface of a support, and an elastic member is loaded between the installed piezoelectric element and the support. Characteristic pulse meter.