JPH08154903A - Biological information monitoring sheet - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a biometric information monitoring sheet for noninvasively and highly accurately measuring biometric information. [Structure] A sensor substrate 1 having a bendable thickness of 0.02 to 0.1 mm is installed between a heat conductive sheet 2 and a heat insulating sheet 3, and a sensor driving source is provided on the surface of the heat insulating sheet 3. A battery 4 and an output terminal 5 for reading measured values are provided. Battery 4
The output terminal 5 is connected to the flexible sensor substrate 1 by the lead wire 10. The sensor substrate 1 includes at least one sensor 8, a signal processing circuit 9, a calculation unit 11, a storage unit 12,
It is composed of the output unit 13. The sensor substrate 1 is sandwiched between the heat conductive sheet 2 and the heat insulating sheet 3 so that the three members are brought into close contact with each other to be integrally formed. [Effect] The biological information can be monitored without restraining the motion and time of the subject.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical sensor,
In particular, the present invention relates to a sheet for non-invasive and continuous monitoring of biological information without restraining the operation and time of the patient, imposing a burden on the patient.

[0002]

2. Description of the Related Art Sensors and Actuators B1 is a method for measuring biochemical components in biological fluids.
(1990) pp. 488-492 (Senso
rs and Actuators, B1 (1990)
pp488-pp492), a method of peeling the skin on the surface of a living body and measuring the glucose concentration in the exudate from the surface using a semiconductor sensor is described.

[0003]

SUMMARY OF THE INVENTION In the above prior art,
It is an invasive method of peeling the skin surface before measurement, and the subject needs to be stationary at the measurement site during measurement,
There is a problem that the subject's time and movement are restricted.

[0004]

[Means for Solving the Problems] The above problem is caused by installing a sensor substrate on the surface of or in a flexible sheet having good thermal conductivity, and stacking a sheet having good thermal conductivity and a flexible sheet having heat insulating properties. It is solved by forming it integrally. Further, the sensor substrate is made thin to be flexible, and the conformity with the flexible sheet is improved.

More specifically, the biological information monitoring sheet of the present invention comprises a sensor substrate, a flexible heat conductive sheet which contacts the sensitive surface of the sensor substrate, and a flexible heat insulation which contacts the back surface of the sensitive surface of the sensor substrate. Is a biometric information monitoring sheet including a heat conductive sheet, the sensor substrate is sandwiched between the heat conductive sheet and the heat insulating sheet, and the heat conductive sheet and the heat insulating sheet are integrated to form a heat insulating sheet. Is a battery, or a thermo-electric converter is embedded, semiconductor laser at different positions of the heat conductive sheet,
Each photodetector is embedded. The heat conductive sheet is attached to the inspection target such that the heat conductive sheet contacts the inspection target surface.

The sensor substrate includes one kind or plural kinds of sensors for detecting temperature, pressure, electric potential, ions, gas and biochemical substances, and a signal processing circuit for processing signals from the sensors, an arithmetic unit, a storage unit, A plurality of sensors of the same type may be two-dimensionally arranged on the sensor substrate, including an output unit (the output unit includes a transmission circuit and an antenna). The sensor substrate is a silicon substrate that has been widely used in the past, or has a thickness of 0.1.
A flexible silicon substrate of mm or less is used.

The wavelength of the semiconductor laser is 1.55 μm
However, if the wavelength of the light emitted from the semiconductor laser wavelength has a width, it is 1.5 μm to 1.7 μm.
It may be μm. The wavelength of the semiconductor laser is 2.1 μm to 2.3 μm. The photodetector is made of germanium, indium-gallium arsenide, lead selenide, or lead sulfide, and is 0.7 μm to 3 μm.
It has a peak sensitivity wavelength in the range of m.

[0008]

Since the flexible sheet made of a material having a good thermal conductivity and the heat insulating material and the sensor substrate are integrally formed, the flexible sheet can be attached in close contact with the curved surface of the body surface or the like. The surface of the flexible sheet that comes into contact with the body surface is made of a material with good thermal conductivity, and the surface of the opposite side that comes into contact with air is made of a heat insulating material, so it is affected by changes in the external environment such as temperature and wind. The body temperature can be measured with high accuracy. Also,
Since the temperature of various sensors such as a temperature sensor, the semiconductor laser, the photodetector, and the peripheral circuit can be made substantially equal to the body temperature and substantially constant, highly accurate measurement can be performed. As a result, the biological information can be measured non-invasively and highly accurately without restraining the motion and time of the subject.

[0009]

【Example】

(First Embodiment) FIG. 1A shows a sectional view of a biological information monitoring sheet according to a first embodiment of the present invention. Thickness 0.
A sensor substrate 1 having a size of 02 mm to 0.1 mm and a size of 10 mm is installed between the heat conductive sheet 2 and the heat insulating sheet 3, and the heat insulating sheet 3 has a battery 4 serving as a sensor driving source and an output terminal 5 for reading measured values. Is embedded. The thickness of the monitoring sheet is 0.5-5 mm. Battery 4 and output terminal 5
Is connected to the flexible sensor substrate 1 by a lead wire 10.

The cross-sectional shape of the sensor substrate 1 of this embodiment is shown in FIG.
FIG. 1B shows the cross-sectional shape of the conventional sensor substrate in FIG. In the sensor substrate 6 and the conventional sensor substrate 7, the sensor 8 and the signal processing circuit 9 are formed in a portion having a depth of about 10 μm from the substrate surface. Sensor substrate 6 of this embodiment
Then, an unnecessary portion on the back surface side of the conventional sensor substrate 7 was removed by etching or the like to form a thin substrate having a thickness of 0.05 mm. In the sensor substrate 6 of this embodiment, the central portion of the substrate can be curved concavely or convexly. In the state of maximum bending, the center of the substrate moves by 3 mm in the direction perpendicular to the plane before the bending.

The sensor substrate 1 shown in FIG. 1 (d) is composed of at least one sensor 8, a signal processing circuit 9, an arithmetic unit 11, a storage unit 12 and an output unit 13. In the output unit 13, a transmission circuit including a coil, a capacitance, a resistance and the like and an antenna are integrated. The sensor substrate 1 is made of silicon,
Sensor, sensor signal processing circuit, arithmetic circuit, memory circuit,
Although it is desirable to integrate the output circuit and the like on-chip, individual chips such as the sensor chip, the signal processing circuit chip, and the memory circuit chip may be hybrid-formed on the insulating substrate.

The heat conductive sheet 2 may be made of metal, semiconductor or polymer, and the heat insulating sheet 3 may be made of asbestos, foamed styrene, foamed urethane or glass fiber. The sensor substrate 1 is sandwiched between the heat conductive sheet 2 and the heat insulating sheet 3 so that the three members are brought into close contact with each other to be integrally formed. The integrated sheet has dimensions of a thickness of 5 mm, a width of 30 mm and a length of 60 mm, and can be adhered to a cylindrical living body surface having a cross-sectional diameter of 10 mm.

FIG. 2 shows a sectional structure of a temperature sensor using a silicon substrate. The temperature can be obtained most easily by utilizing the temperature dependence of the forward current of the pn junction as shown in (Equation 1).

[0014]

## EQU00001 ## I = A.exp (qV / (kT)) (Equation 1) where I is current, A is constant, q is unit charge, V is applied voltage, k is Boltzmann constant, Each T represents an absolute temperature. As shown in FIG. 2, silicon oxide 15 is formed on the surface of the p-type silicon substrate 14, and a hole is formed in a part of the silicon oxide 15 to form an n-type region 16 and p + in the p-type silicon.
Region 17 is formed. A metal electrode 18 of aluminum or the like is formed in the n-type region and the p + region and connected to the signal processing unit (circuit).

FIG. 3 shows a sectional structure of an oxygen gas sensor using a silicon substrate. A solid electrolyte film 21 is formed on a gate insulating film 20 of an insulated gate field effect transistor 19, and a noble metal thin film 22 is provided as a gate electrode. It is possible to use yttria-stabilized zirconia, calcia-stabilized zirconia, lanthanum fluoride, lead tin oxide or the like as the solid electrolyte membrane 21, and platinum, palladium, iridium, gold or the like as the gate electrode 22. The potential of the gate electrode / solid electrolyte interface changes according to the partial pressure of oxygen in the vicinity of the gate electrode 22, which changes the gate voltage and changes the drain current of the field effect transistor. This oxygen sensor operates in a wide temperature range from room temperature to around 200 ° C.

FIG. 4 shows a sectional structure of a potential measuring electrode using a silicon substrate. Silicon oxide 24 is formed on the silicon substrate 23, and the potential measuring electrode film 25 is patterned. As the potential measuring electrode film 25, platinum, gold or the like is used. This electrode is placed on the body surface, and the potential change induced on the body surface in synchronization with the movement of the heart is measured by the potential difference between the two electrodes,
That is, it is measured as an electrocardiogram. Two potential measuring electrode films 25
It can be formed in a three-dimensional array and arranged on the body surface, and the potential difference between each electrode can be analyzed to know the heart disease in detail.

(Second Embodiment) FIG. 5 shows a sectional view of a living body information monitoring sheet of the second embodiment of the present invention which is bent and used. The flexible sensor substrate 1 is sandwiched between the heat conductive sheet 2 and the heat insulating sheet 3 so that the three members are brought into close contact with each other to be integrally formed. The size of the integrated sheet is, for example, when using the monitoring sheet in the earlobe,
The thickness is 0.5 mm, the width is 3 mm, and the length is 3 mm, and the size of the integrated sheet may be determined according to the site where the monitoring sheet is used. A battery 4 serving as a sensor drive source and an output terminal 5 for reading a measured value are embedded in the heat insulating sheet 3. The battery 4 and the output terminal 5 are connected to the flexible sensor substrate 1 by a lead wire 10 (not shown in FIG. 5).

The semiconductor laser 26 is embedded in the heat conductive sheet 2 at one end in the longitudinal direction of the monitoring sheet, and the photodetector 27 is embedded in the heat conductive sheet 2 at the other end in the longitudinal direction. This biometric information monitoring sheet is bent so that the semiconductor laser 26 and the photodetector 27 face each other so that the photodetector 27 is positioned on the optical axis of the emitted light of the semiconductor laser 26 as shown in FIG. The test object is placed between the semiconductor laser 26 and the photodetector 27.

Electric power is supplied to the semiconductor laser 26, the photodetector 27 and peripheral circuits by the battery 4 embedded in the monitoring sheet. It should be noted that instead of the battery, a different metal or semiconductor is used as the heat-electricity converter, and the heat conductive sheet 2,
It can be installed in the heat insulating sheet 3 and used as a power source for joining two kinds of metals or semiconductors at the boundary surface between the heat conductive sheet 2 and the heat insulating sheet 3. It is desirable that this bonding be installed in a portion where the heat conductive sheet 2 is in contact with the subject (living body). A temperature difference occurs between the two metals or semiconductors, and an electromotive force is generated in the two metals or semiconductors due to the Seebeck effect. This electromotive force can be used as a power source for the sensor board, and the body temperature of the subject is used as a heat source.
A stable electromotive force can be supplied to the sensor substrate for a long period of time.

(Third Embodiment) FIG. 6 shows a sectional view of a cylindrical biological information monitoring sheet according to a third embodiment of the present invention. The inner surface of the cylindrical monitoring sheet is the heat conductive sheet 2, and the outer surface is the heat insulating sheet 3. Similar to the second embodiment, the flexible sensor substrate 1 is sandwiched between the heat conductive sheet 2 and the heat insulating sheet 3 so that the three members are brought into close contact with each other to be integrally formed. The dimensions of the integrated cylindrical sheet are
When considered as a cylinder, for example, the sheet thickness is 1 mm, the cylinder height is 2 mm, and the cylinder inner diameter is 20 mm. Heat insulation sheet 3
A battery 4 as a sensor drive source and an output terminal 5 for reading out a measured value are embedded in the. The battery 4 and the output terminal 5 are provided on the flexible sensor substrate 1 with lead wires 10 (not shown in FIG. 6).
Connected by.

The semiconductor laser 26 is embedded in the heat conductive sheet 2, and the photodetector 27 is embedded so as to face the semiconductor laser 26 so that the photodetector 27 is located on the optical axis of the emitted light of the semiconductor laser 26. . The subject is placed inside the cylindrical sheet between the semiconductor laser 26 and the photodetector 27. Power is supplied to the semiconductor laser, the photodetector and the peripheral circuits in the same manner as in the second embodiment.

(Fourth Embodiment) FIG. 7 shows an example in which the biological information monitoring sheet of the first embodiment is used to continuously monitor the body temperature without restraining the motion and time of the subject. The biological information monitoring sheet 29 is brought into close contact with the surface of the living body 28, and the body temperature is measured at preset constant time intervals. The two-dimensional temperature distribution of the living body can be measured using the sensor substrate on which the two-dimensional array temperature sensor is formed. The monitoring sheet of the present invention has a thickness of 1 to 5 mm and is very thin, so that the subject can live a normal life without feeling uncomfortable. After the end of the measurement period, the biological information monitoring sheet can be removed from the living body, and the information reading device can obtain information on changes in body temperature over time. When a sensor substrate having a two-dimensional array temperature sensor is used, a two-dimensional temperature distribution map of the living body can be drawn by connecting the biological information monitoring sheet to an external display device.

(Fifth Embodiment) FIG. 8 shows an example of monitoring the blood glucose level, that is, glucose, using the biological information monitoring sheet of the second embodiment. A semiconductor laser and a photodetector are installed near both ends in the longitudinal direction of the U-shaped bent biological information monitoring sheet 29, and the living body is used between the semiconductor laser and the photodetector. That is, the biological information monitoring sheet 29 is sandwiched by the earlobe 30 to measure glucose.

The light source is a semiconductor laser made of indium, gallium, arsenic and antimony, and the wavelength of the emitted light is 2.2 μm. A photodetector made of lead sulfide was used. This photodetector has a peak sensitivity at 2.2 μm. Part of the light emitted from the semiconductor laser is absorbed by glucose. Glucose can be quantitatively measured from the intensity of the transmitted light measured by the photodetector, using the calibration data obtained from the intensity of the transmitted light of glucose of known concentration. The sampling time and the reading method are the same as those in the fourth embodiment. In the present embodiment, the biological information monitoring sheet can be used like earrings, and glucose can be measured non-invasively without restraining the time and motion of the subject.

(Sixth Embodiment) FIG. 9 shows an example of monitoring glucose by using the biological information monitoring sheet of the third embodiment. The arm 31 is used through the biological information monitoring sheet 29 of the third embodiment to measure glucose.

The light source is a semiconductor laser made of indium, gallium, arsenic and phosphorus, and the wavelength of the emitted light is 1.55 μm. A photodiode made of germanium was used as the photodetector. This photodetector is 1.
It has a peak sensitivity at 55 μm. The principle of glucose measurement is the same as in Example 5. In the present embodiment, the biological information monitoring sheet can be used like a wristwatch, and similarly to the fifth embodiment, glucose can be measured non-invasively without restraining the time and movement of the subject.

[0027]

Since the biological information monitoring sheet of the present invention is thin and flexible, it can be attached in close contact with the curved surface of the biological surface, and the examinee does not feel any discomfort while living a normal life. Biological information can be monitored. Further, since the biological information monitoring sheet of the present invention is integrally formed by laminating a sheet having good thermal conductivity and a sheet having heat insulating properties, the biological information is not affected by changes in surrounding environment such as temperature and wind. Can be monitored with high accuracy.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a sectional view of a temperature sensor.

FIG. 3 is a sectional view of a gas sensor.

FIG. 4 is a sectional view of a potential measuring electrode.

FIG. 5 is a sectional view showing a second embodiment of the present invention.

FIG. 6 is a sectional view showing a third embodiment of the present invention.

FIG. 7 is a diagram showing a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a fifth embodiment of the present invention.

FIG. 9 is a diagram showing a sixth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sensor substrate, 2 ... Thermally conductive sheet, 3 ... Thermal insulation sheet, 4 ... Battery, 5 ... Output terminal, 6 ... Sensor substrate of this invention, 7 ... Conventional sensor substrate, 8 ... Sensor, 9 ... Signal processing Circuit, 10 ... Lead wire, 11 ... Arithmetic unit, 12 ... Storage unit,
13 ... Output part, 1, 15 ... Silicon oxide, 16 ... N-type region, 17 ... P + region, 18 ... Metal electrode, 19 ... Field effect transistor, 20 ... Gate insulating film, 21 ... Solid electrolyte film, 22 ... Noble metal gate Electrodes, 23 ... Silicon substrate, 2
4 ... Silicon oxide, 25 ... Metal electrode for potential measurement, 26 ...
Semiconductor laser, 27 ... Photodetector, 28 ... Living body, 29 ... Biological information monitoring sheet, 30 ... Earlobe, 31 ... Arm.

Claims (13)

[Claims] 1. A biological information monitoring sheet comprising a sensor substrate, a flexible heat conductive sheet that contacts the sensitive surface of the sensor substrate, and a flexible heat insulating sheet that contacts the back surface of the sensitive surface of the sensor substrate. A biometric information monitoring sheet, wherein the sensor substrate is sandwiched between the heat conductive sheet and the heat insulating sheet, and the heat conductive sheet and the heat insulating sheet are integrated. 2. The biological information monitoring sheet according to claim 1, wherein a battery or a thermoelectric converter is embedded in the heat insulating sheet. 3. The biological information monitoring sheet according to claim 1, wherein a semiconductor laser and a photodetector are embedded in different positions of the heat conductive sheet. 4. The sensor substrate includes one kind or a plurality of kinds of sensors for detecting temperature, pressure, electric potential, ions, gas and biochemical substance, and a signal processing circuit for processing a signal from the sensor and an arithmetic unit. The biological information monitoring sheet according to claim 1, further comprising: a storage unit and an output unit. 5. The biological information monitoring sheet according to claim 4, wherein a plurality of the same type of the sensors are two-dimensionally arranged on the sensor substrate. 6. The biological information monitoring sheet according to claim 4, wherein the sensor substrate is a silicon substrate. 7. The biological information monitoring sheet according to claim 4, wherein the sensor substrate is made of a flexible silicon substrate, and the thickness of the silicon substrate is 0.1 mm or less. 8. The biological information monitoring sheet according to claim 3, wherein the wavelength of the semiconductor laser is 1.55 μm. 9. The biological information monitoring sheet according to claim 3, wherein the wavelength of the semiconductor laser is from 1.5 μm to 1.7 μm. 10. The biological information monitoring sheet according to claim 3, wherein the wavelength of the semiconductor laser is 2.1 μm to 2.3 μm. 11. The biological information monitoring sheet according to claim 3, wherein the photodetector has a peak sensitivity wavelength in the range of 0.7 μm to 3 μm. 12. The biological information monitoring sheet according to claim 4, wherein the output unit includes a transmission circuit and an antenna. 13. The biological information monitoring sheet according to claim 1, wherein the heat conductive sheet is in contact with a surface to be inspected.