KR102162552B1 - Biological signal measurement sensor using polylactic acid piezoelectric material - Google Patents

Abstract

The present invention discloses a non-constrained bio-signal measuring sensor. According to an embodiment of the present invention, it is possible to provide a bio-signal measurement sensor capable of measuring a bio-signal with high sensitivity without being directly attached to a user's body or restrained by pressure.

Description

Bio-signal measurement sensor using polylactic acid piezoelectric material {BIOLOGICAL SIGNAL MEASUREMENT SENSOR USING POLYLACTIC ACID PIEZOELECTRIC MATERIAL}

The present invention relates to a bio-signal measurement sensor, and more particularly, to a bio-signal measurement sensor capable of measuring bio-signals such as respiration, pulse, and heart rate in an unconstrained state in which the sensor is not attached to the body.

Snoring refers to a symptom in which a sound is generated by vibrating the soft palate (a relatively soft back part of the ceiling of the mouth), uvula and surrounding mucous membranes, etc., when air passes through the narrowed oral cavity due to the stretch of muscles during sleep. Sleep apnea is a symptom of stopping breathing by closing the airway by increasing tissues around the airways during sleep.Apnea of 10 seconds or more occurs 5 times per hour or more than 30 times per 7 hours during sleep. It refers to the symptoms of a sleep disorder.

If there are symptoms of sleep disorders caused by sleep apnea, the quality of sleep deteriorates due to arousal during repeated sleep, which is the cause of lowering the quality of life, and in severe cases can cause serious diseases such as cardiovascular complications.

The most convenient factors for diagnosing abnormalities in the circadian rhythm such as sleep apnea are heart rate and respiration, and in order to easily measure these, conventional bio-signal measuring devices attach sensor electrode patches with electrical conductivity directly to the skin. The heart rate and respiration rate were displayed through a display device so that the administrator can visually check the electrical signal generated by the heart.

That is, by attaching the bio-signal measuring device directly to the patient's body, the patient feels uncomfortable, which makes it difficult to diagnose an exact disease.

To solve this problem, a technology for measuring a biological signal without restraining a patient by applying a piezoelectric polymer to a patient's clothing is currently being developed.

However, polyvinylidene difluoride (PVDF), which is widely known as a conventional piezoelectric polymer, is not only expensive, but also uses a high voltage to produce piezoelectric properties, so that dipoles inside the chain in the polymer are arranged in a certain direction. The polarization phenomenon must be induced, and even if the polarized dipole reaches a temperature of 60 to 70 degrees, the polarized dipole returns in a disorderly manner, so that the piezoelectric phenomenon is no longer displayed.

Korean Patent Publication No. 10-2017-0108462,'Sleep Apnea Monitoring System' Korean Patent Publication No. 10-2009-0053441,'Non-contact bio-signal measuring device using piezoelectric sensor' Korean Patent Application Publication No. 10-2015-0021298,'Wearable biosignal interface and operation method of wearable biosignal interface'

The present invention provides a bio-signal measurement sensor capable of measuring bio-signals such as respiration, pulse, and heart rate in an unconstrained state in which the sensor is not attached to the body.

The non-constrained bio-signal measurement sensor according to an embodiment of the present invention includes a polylactic acid piezoelectric material film formed by stretching a polylactic acid (PLA) film; An upper electrode formed on the polylactic acid piezoelectric material film; And a polylactic acid piezoelectric sensor including a lower electrode formed under the polylactic acid piezoelectric material film, and at least one upper elastic layer formed on one side of the polylactic acid piezoelectric sensor; At least one lower elastic layer formed on the other side of the polylactic acid piezoelectric sensor; And a protective layer sealing the polylactic acid piezoelectric sensor, an upper elastic layer and a lower elastic layer, wherein the at least two or more upper elastic layers and the lower elastic layers are formed to cross and do not overlap with each other. To do.

In the non-binding biosignal measurement sensor according to an embodiment of the present invention, as long as 80% or more of the monomers constituting the polylactic acid film are selected from L-isomer or D-isomer. It is characterized by consisting of a kind of isomer.

In the non-constrained bio-signal measurement sensor according to an embodiment of the present invention, the polylactic acid piezoelectric material film is a film obtained by stretching the polylactic acid film at a drawing ratio (DR) of 3 to 5. .

In the non-constrained biosignal measurement sensor according to an embodiment of the present invention, the polylactic acid piezoelectric material film is formed by cutting the polylactic acid film at an angle of 22.5° to 67.5° in a stretching direction.

In the non-constrained bio-signal measurement sensor according to an embodiment of the present invention, the upper elastic layer and the lower elastic layer are formed of an elastic sponge.

In the non-constrained bio-signal measurement sensor according to an embodiment of the present invention, the protective layer is formed of a protective fabric.

In the non-constrained bio-signal measuring sensor according to an embodiment of the present invention, the polylactic acid piezoelectric sensor further includes an electrode connection unit capable of transmitting an electrical signal from the electrode to the outside of the sensor.

In the non-constrained bio-signal measurement sensor according to an embodiment of the present invention, the non-constrained bio-signal measurement sensor measures the user's respiration, pulse rate, and heart rate when the user sleeps.

According to an embodiment of the present invention, since the polylactic acid film has piezoelectric properties only by the stretching process, it is possible to provide a non-constrained biosignal measurement sensor manufactured through inexpensive materials and manufacturing processes.

According to an embodiment of the present invention, the polylactic acid film is stretched at a draw ratio of 3 to 5 and cut at a cutting angle of 22.5° to 67.5° to provide a non-constrained biosignal measurement sensor in which a piezoelectric signal is maximized.

According to an embodiment of the present invention, shear force generated in the non-overlapping structure by external pressure is efficiently generated through the upper elastic layer and the lower elastic layer of the structure that do not overlap each other formed intersecting each other, so that a piezoelectric signal due to shear pressure is generated. By using a sensor structure that can be generated larger, it is possible to provide a sensor for measuring a biological signal more effectively and sensitively.

1 is a cross-sectional view of a polylactic acid piezoelectric sensor constituting a non-constrained bio-signal measurement sensor according to an embodiment of the present invention.
2 is a cross-sectional view of the entire structure of a non-constrained bio-signal measuring sensor according to an embodiment of the present invention.
3A to 3D are graphs showing piezoelectric signals of polylactic acid piezoelectric sensors according to embodiments of the present invention.
4A is a graph showing a piezoelectric peak-to-peak output according to a cutting angle in a polylactic acid piezoelectric sensor according to an embodiment and a comparative example of the present invention.
4B is a graph showing piezoelectric peak-to-peak output according to a draw ratio in a polylactic acid piezoelectric sensor according to an embodiment and a comparative example of the present invention.
4C is a graph showing birefringence according to an elongation ratio in a polylactic acid piezoelectric sensor according to an embodiment and a comparative example of the present invention.
4D is a graph showing a correlation between birefringence and a piezoelectric voltage in a polylactic acid piezoelectric sensor according to an embodiment and a comparative example of the present invention.
5 is a graph showing a piezoelectric signal generated by a silicon-coated non-constrained bio-signal measuring sensor according to another embodiment of the present invention.
6A and 6B are graphs showing a result of simultaneously measuring the magnitude of piezoelectric signals according to Example 6 and Comparative Example 6 of the present invention on an actual mattress.
7A to 7D are graphs showing the biosignals obtained when the subject sleeps after installing the silicone-coated non-constrained biosignal measurement sensor according to the sixth embodiment of the present invention on the mattress.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and contents described in the accompanying drawings, but the present invention is not limited or limited by the embodiments.

The terms used in the present specification are for describing exemplary embodiments and are not intended to limit the present invention. In this specification, the singular form also includes the plural form unless specifically stated in the phrase. As used in the specification, "comprises" and/or "comprising" refers to the presence of one or more other components, steps, actions and/or elements, and/or elements, steps, actions and/or elements mentioned. Or does not exclude additions.

As used herein, "embodiment", "example", "side", "example" and the like should be construed as having any aspect or design described better or advantageous than other aspects or designs. Is not.

In addition, the term'or' means an inclusive OR'inclusive or' rather than an exclusive OR'exclusive or'. That is, unless stated otherwise or unless clear from context, the expression'x uses a or b'means any one of natural inclusive permutations.

In addition, the singular expression ("a" or "an") used in this specification and the claims generally means "one or more" unless otherwise stated or unless it is clear from the context that it relates to the singular form. Should be interpreted as.

The terms used in the description below have been selected as general and universal in the related technology field, but there may be other terms depending on the development and/or change of technology, customs, preferences of technicians, and the like. Therefore, terms used in the following description should not be understood as limiting the technical idea, but should be understood as exemplary terms for describing embodiments.

In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, detailed meanings will be described in the corresponding description. Therefore, terms used in the following description should be understood based on the meaning of the term and the contents throughout the specification, not just the name of the term.

Meanwhile, terms such as first and second may be used to describe various components, but the components are not limited by terms. The terms are used only for the purpose of distinguishing one component from another.

In addition, when a part such as a film, layer, region, configuration request, etc. is said to be "on" or "on" another part, not only is it directly above another part, but also another film, layer, region, component in the middle thereof. This includes cases where such as are interposed.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used as meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

Meanwhile, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. In addition, terms used in the present specification are terms used to properly express an embodiment of the present invention, which may vary depending on the intention of users or operators, or customs in the field to which the present invention belongs. Accordingly, definitions of these terms should be made based on the contents throughout the present specification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a polylactic acid piezoelectric sensor constituting a non-constrained bio-signal measurement sensor according to an embodiment of the present invention.

Referring to FIG. 1, the polylactic acid piezoelectric sensor 100 includes a polylactic acid piezoelectric material film 110 formed by stretching a polylactic acid film, and an upper electrode formed on the polylactic acid piezoelectric material film 110. 120 and a lower electrode 130 formed under the polylactic acid piezoelectric material film 110.

Polylactic acid is an eco-friendly polymer with excellent biodegradation properties, and has been widely studied due to the characteristic of generating a piezoelectric current through shear deformation.

The α-crystalline form of polylactic acid is the most thermodynamically stable at room temperature, and can be easily obtained by melting or solution spinning. However, in the unstretched PLA film, such molecular chains are randomly oriented, and C=O dipole groups are helically oriented along the molecular chain, and accordingly, the net dipole moment becomes zero, so it does not exhibit piezoelectric properties.

These drawbacks can be overcome by polylactic uniaxially stretching the film at a high temperature lactic acid, which is converted to β- crystal form having a 3 ₁ helical form along the polymer chain α- crystalline polylactic acid film having a spiral shape 10 ₃ overcome Can be.

Lactic acid, a monomer of polylactic acid, is an optical isomer, and has two forms, D-isomer and L-isomer, and polylactic acid consisting of D-isomer is poly-D- Polylactic acid consisting of lactic acid [poly(D-lactic acid), PDLA] and L-isomer is referred to as poly-L-lactic acid [poly(L-lactic acid), PLLA].

The stretching conditions of the polylactic acid and the composition of the 7 polylactic acid isomer will be described in more detail in Examples to be described later.

In particular, the polylactic acid piezoelectric material film 110 of the polylactic acid piezoelectric sensor 100 according to an embodiment of the present invention is drawn at a drawing ratio (DR) of 3 to 5 and then 22.5° to 67.5 in the drawing direction. It is characterized in that it is formed by cutting at an angle of °.

In particular, the polylactic acid piezoelectric material film 111 of the polylactic acid piezoelectric sensor 100 according to an embodiment of the present invention is further formed by stretching at a draw ratio of 4 and then cutting at an angle of 45° in the stretching direction. desirable.

The draw ratio and the cutting angle when forming the polylactic acid piezoelectric material film will be described in more detail in the embodiments of the present invention to be described later.

An upper electrode 120 is formed on the polylactic acid piezoelectric material film 110 constituting the polylactic acid piezoelectric sensor 100 according to an embodiment of the present invention, and the polylactic acid piezoelectric material film 110 A lower electrode 130 is formed on the lower side.

The upper electrode 120 and the lower electrode 130 may be formed of at least one of a metal foil paper, a conductive fiber, a conductive fabric, a conductive polymer film, and a conductive nanoweb, and the electrodes 112 and 113 Elastic electrodes that can be compressed and stretched are also available.

2 is a cross-sectional view of the entire structure of a non-constrained bio-signal measuring sensor according to an embodiment of the present invention.

Referring to FIG. 2, the non-constrained bio-signal measurement sensor 200 according to an embodiment of the present invention includes at least one polylactic acid piezoelectric sensor 210 and at least one formed on one side of the polylactic acid piezoelectric sensor 210. The upper elastic layer 220, at least one lower elastic layer 230 formed on the other side of the polylactic acid piezoelectric sensor 210, the polylactic acid piezoelectric sensor 210, the upper elastic layer 220, and the lower elastic layer It includes a protective layer 240 for sealing 230.

The non-constrained biosignal measurement sensor 200 according to an embodiment of the present invention includes at least one upper elastic layer 220 formed on one side of the polylactic acid piezoelectric sensor 210, and the polylactic acid piezoelectric sensor 210 It includes at least one lower elastic layer 230 formed on the other side of the.

The upper elastic layer 220 and the lower elastic layer 230 are formed of at least one selected from an elastic sponge and an elastic fiber.

The upper elastic layer 220 and the lower elastic layer 230 are also formed to cross and have a structure that does not overlap each other.

If the upper elastic layer 220 and the lower elastic layer 230 are formed in a non-overlapping structure, pressure such as heartbeat and respiration coming from the outside can be converted into a shear force change to the piezoelectric sensor, compared to a simple upper and lower elastic body structure. It can have excellent sensor characteristics.

In addition, such a structure is installed in a structure in contact with a body such as a mattress, so that a user's discomfort when measuring a physiological signal can be minimized, and accuracy of measuring a physiological signal can be improved.

The non-constrained bio-signal measurement sensor 200 according to an embodiment of the present invention includes a polylactic acid piezoelectric sensor 210, an upper elastic layer 220, and a protective layer 240 sealing the lower elastic layer 230. do.

The protective layer 240 may be formed of at least one selected from a protective film and a protective fabric.

The protective layer 240 protects the inner polylactic acid piezoelectric sensor 210, the upper elastic layer 220, and the lower elastic layer 230, and minimizes the user's sense of heterogeneity when installed on a structure in contact with the user's body. There is a purpose.

The protective film and the protective fabric that may constitute the protective layer 240 are made of a material suitable for the purpose of preventing sweat from being in contact with the body by using a material having breathability.

As described above, the non-constrained bio-signal measurement sensor 200 according to an embodiment of the present invention is installed in a structure that contacts the user, that is, the body of the subject, and when the user contacts the structure and the body, the user’s bio-signal is transmitted. I can measure it.

The biometric signals that can be measured include the user's breathing, apnea, heart rate, pulse and movement, and are not limited thereto. Any bio signals that can be measured through a piezoelectric sensor can be measured, and multiple signals can be measured simultaneously.

Hereinafter, the present invention will be described in more detail through examples. These examples are for explaining the present invention more specifically, and the scope of the present invention is not limited by these examples.

[matter]

Polylactic acid (PLA 4032D, Mw=195,000) consisting of 2% D-isomer and 98% L-isomer was purchased from NatureWorks®, USA and used to prepare a polylactic acid film.

A silicone elastomer base and silicone elastomer curing agent (Sylgard® 184A and 184B) were purchased from Dow Corning, USA and used in the silicone coating process to improve friction with the protective layer.

The silicone elastomer base and the silicone elastomer curing agent were used for the purpose of forming the silicone coating layer of the elastic body. When the silicone coating is performed, it is possible to prevent the polylactic acid film from slipping, so that the shear force conversion by pressure becomes easier.

In addition, an adhesive nickel-copper plated polyester fabric (J. S. Korea Inc) was used as the upper and lower electrodes.

[Example 1]

Polylactic acid consisting of 2% D-isomer and 98% L-isomer was stretched at a draw ratio of 4.5 and then cut at 45° in the stretching direction to prepare a polylactic acid piezoelectric material film.

Thereafter, an adhesive nickel-copper plated polyester fabric was adhered to the upper and lower portions of the polylactic acid piezoelectric material film, and an upper electrode and a lower electrode were formed to manufacture a polylactic acid piezoelectric sensor.

[Example 2]

[Example 2] was prepared in the same manner as in [Example 1], except that the stretched polylactic acid film was cut at 22.5° in the stretching direction.

[Example 3]

[Example 3] was prepared in the same manner as in [Example 1], except that the stretched polylactic acid film was cut at 67.5° in the stretching direction.

[Example 4]

[Example 4] was prepared in the same manner as in [Example 1], except that the polylactic acid film was stretched at a draw ratio of 4.0.

[Example 5]

In [Example 5], the sensor prepared in [Example 1] was coated and cured using silicone rubber, and then a protective fiber was coated thereon to prepare a sensor.

[Example 6]

In [Example 6], a double-sided adhesive elastic sponge (3M company) was disposed on the upper and lower portions of the sensor manufactured in [Example 1] so as to cross each other as shown in Fig. 2, and a protective fiber was coated thereon to prepare a sensor.

[Comparative Example 1]

[Comparative Example 1] was prepared in the same manner as in [Example 1], except that the stretched polylactic acid film was cut at 0° in the stretching direction.

[Comparative Example 2]

[Comparative Example 2] was prepared in the same manner as in [Example 1], except that the stretched polylactic acid film was cut at 90° in the stretching direction.

[Comparative Example 3]

[Comparative Example 3] was prepared in the same manner as in [Example 1], except that the polylactic acid film was not stretched. (Because it has not been through the stretching process, it is cut in an arbitrary direction.)

[Comparative Example 4]

[Comparative Example 4] was prepared in the same manner as in [Example 1], except that the polylactic acid film was stretched at a draw ratio of 3.3.

[Comparative Example 5]

[Comparative Example 5] was prepared in the same manner as in [Example 1], except that the polylactic acid film was stretched at a draw ratio of 3.5.

[Comparative Example 6]

In [Comparative Example 6], a sensor was manufactured by coating a protective fiber on the sensor made in Example 1.

Hereinafter, characteristics of the non-constrained bio-signal measuring sensor according to the embodiments and comparative examples of the present invention will be described in detail with reference to the drawings.

3A to 3D are graphs showing piezoelectric signals of polylactic acid piezoelectric sensors according to embodiments of the present invention.

FIG. 3A is a graph showing a piezoelectric signal of the polylactic acid piezoelectric sensor according to Example 1 of the present invention. Referring to FIG. 3A, polylactic acid is stretched at a draw ratio of 4.5 and then cut at 45° in the stretching direction. It can be seen that the lactic acid piezoelectric material film shows the maximum output voltage.

3B to 3D are graphs showing piezoelectric signals of the polylactic acid piezoelectric sensors according to Embodiments 2 to 4 of the present invention. Referring to Figs. 3B to 3D, somewhat compared to Embodiment 1 of the present invention. It shows a low output voltage, but it can be seen that it shows an output voltage that can be used as a sensor.

3E to 3I are graphs showing piezoelectric signals of polylactic acid piezoelectric sensors according to comparative examples of the present invention.

3E to 3I, it is confirmed that the output voltage is relatively low compared to the embodiments of the present invention, and thus it can be seen that it is difficult to use it as a sensor.

4A is a graph showing a piezoelectric peak-to-peak output according to a cutting angle in a polylactic acid piezoelectric sensor according to an embodiment and a comparative example of the present invention.

Referring to FIG. 4A, it can be seen that the best output is displayed when the cutting angle is 45°.

4B is a graph showing piezoelectric peak-to-peak output according to a draw ratio in a polylactic acid piezoelectric sensor according to an embodiment and a comparative example of the present invention.

Referring to FIG. 4B, it can be seen that the piezoelectric peak-to-peak output rapidly increases from the draw ratio of 3.5, which means that the polylactic acid film is necked from the draw ratio of 3.5. In addition, it can be confirmed that orientation occurs after the necking phenomenon during the stretching process of the polylactic acid film.

4C is a graph showing birefringence according to an elongation ratio in a polylactic acid piezoelectric sensor according to an embodiment and a comparative example of the present invention.

It can be seen that the graph of FIG. 4C also rapidly increases the birefringence value from the draw ratio of 3.5, like the graph of FIG. 4B.

4D is a graph showing a correlation between birefringence and a piezoelectric voltage in a polylactic acid piezoelectric sensor according to an embodiment and a comparative example of the present invention.

Referring to FIG. 4D, it can be seen that the piezoelectric voltage is linearly proportional to birefringence.

5 is a graph showing a piezoelectric signal generated by a silicon-coated non-constrained bio-signal measuring sensor according to another embodiment of the present invention.

5, the silicon-coated non-constrained bio-signal measurement sensor according to the fifth embodiment of the present invention facilitates the transfer of shear force to the sensor by the silicon coating, so that the piezoelectric signal is larger than that of Comparative Example 5 without the silicon coating. can confirm.

6A and 6B are graphs showing results obtained by simultaneously measuring the magnitude of piezoelectric signals according to Example 6 and Comparative Example 6 on an actual mattress.

6A is a result of measurement on a mattress according to Example 6 of the present invention, and FIG. 6B is a result of measurement on a mattress according to Comparative Example 6 of the present invention.

6A and 6B, it is shown that the biosignal result of FIG. 6A according to Example 6 is larger than the biosignal value of FIG. 6B according to Comparative Example 6, which is a crossover of upper and lower elastic sponges or elastic bodies This is a result showing that it is a method of effectively transmitting shear force to the piezoelectric sensor by placing it as

7A to 7D are graphs showing the biosignals obtained when the subject sleeps after installing the silicone-coated non-constrained biosignal measurement sensor according to the sixth embodiment of the present invention on the mattress.

7A to 7D, the non-constrained bio-signal measurement sensor according to an embodiment of the present invention is installed to be placed on the back of the subject.

7A is a result of measuring the shape of a signal that appears as a temporal change by detecting a typical respiration and heartbeat, and the respiration and heartbeat signals are mixed and measured in the signal.

7B is a diagram showing that the signal for the time obtained in FIG. 7A is converted into a signal in the frequency domain by Fourier Transformation. The heart rate signal and the respiration signal are separated and shown. In this example, the primary signal It can be seen that the to tertiary signals are separated.

7C is a graph showing biosignal data obtained during sleep of a subject with apnea symptoms.

Referring to FIG. 7C, during the period of the apnea event, the breathing signal disappears and only the heart rate signal is displayed, and the relative pressure due to the heart rate is weaker and faster than the breathing during the period of the apnea event. have.

7D is a graph showing the movement of a subject during normal sleep. When the subject moves, since it shows an irregular frequency and amplitude than that of a normal breathing signal, the subject's movement can be easily confirmed.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are only presented specific examples to aid understanding, and are not intended to limit the scope of the present invention. In addition to the embodiments disclosed herein, it is apparent to those of ordinary skill in the art that other modified examples based on the technical idea of the present invention may be implemented.

100: polylactic acid piezoelectric sensor 110: polylactic acid piezoelectric material film
120: upper electrode 130: lower electrode
200: non-constrained bio-signal measurement sensor 210: polylactic acid piezoelectric sensor
220: upper elastic layer 230: lower elastic layer
240: protective layer

Claims (9)

Stretching the polylactic acid film;
Cutting the stretched polylactic acid film to prepare a polylactic acid piezoelectric material film;
Forming an upper electrode and a lower electrode on the upper and lower portions of the polylactic acid piezoelectric material film, respectively, to manufacture a polylactic acid piezoelectric sensor;
Forming at least one upper elastic layer on one side of the polylactic acid piezoelectric sensor;
Forming at least one lower elastic layer on the other side of the polylactic acid piezoelectric sensor; And
Including the step of forming a protective layer sealing the upper elastic layer and the lower elastic layer of the polylactic acid piezoelectric sensor,
In the step of stretching the polylactic acid film, the polylactic acid film is stretched at a draw ratio of 4 to 4.5,
In the step of preparing the polylactic acid piezoelectric material film, the stretched polylactic acid film is cut at an angle of 22.5° to 67.5° in the stretching direction,
The method of manufacturing a non-constrained bio-signal measuring sensor, characterized in that the upper elastic layer and the lower elastic layer are formed to cross and do not overlap each other.
A polylactic acid piezoelectric material film formed by stretching a polylactic acid film;
An upper electrode formed on the polylactic acid piezoelectric material film; And
A lower electrode formed under the polylactic acid piezoelectric material film
A polylactic acid piezoelectric sensor comprising a,
At least one upper elastic layer formed on one side of the polylactic acid piezoelectric sensor;
At least one lower elastic layer formed on the other side of the polylactic acid piezoelectric sensor; And
A protective layer sealing the polylactic acid piezoelectric sensor, an upper elastic layer and a lower elastic layer
Including,
The polylactic acid piezoelectric material film is a film obtained by stretching the polylactic acid film at a draw ratio of 4 to 4.5,
The polylactic acid piezoelectric material film is formed by cutting the polylactic acid film at an angle of 22.5° to 67.5° in the stretching direction,
The at least one upper elastic layer and the lower elastic layer are formed to cross and have a structure that does not overlap with each other.
The method of claim 2,
Non-constrained biosignal measurement sensor, characterized in that at least 80% of the monomers constituting the polylactic acid film are made of one type of isomer selected from L-isomer or D-isomer.
delete delete The method of claim 2,
Wherein the upper elastic layer and the lower elastic layer are formed of at least one selected from an elastic sponge and an elastic fiber.
The method of claim 2,
The protective layer is a non-constrained biosignal measurement sensor, characterized in that formed of at least one selected from a protective film (protect film) and a protective fabric (protect fabric).
The method of claim 2,
The polylactic acid piezoelectric sensor,
Non-constrained bio-signal measurement sensor, characterized in that it further comprises an electrode connection portion capable of transmitting an electrical signal from the electrode to the outside of the sensor.
The method of claim 2,
The non-constrained bio-signal measurement sensor,
A non-constrained bio-signal measurement sensor, characterized in that for measuring the user's breathing, apnea, pulse, heart rate, movement and snoring during a user's sleep.

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