JP2003164438A - Noninvasive living body measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make accurate measurements even while a living body is moving. <P>SOLUTION: Three pressure sensors 17, 12 and 7 provided along the directions of mutually perpendicular three axes are used to detect pressures applied to a measurement sampler 18 with which a subject B makes contact, and a living body retaining arm 3 supporting the subject B can also be moved by a triaxial movement stage 2 in the directions of the three axes. During measurement, the triaxial movement stage 2 is controlled so that the pressures detected by the three pressure sensors 17, 12 and 7 become equal to a desired value, whereby the position of the subject B in space is adjusted to hold the pressure of contact constant in accordance with the movement of the subject B. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-invasive living body measuring device for measuring various information regarding the inside of a living body without invading the living body with a needle or the like.

[0002]

2. Description of the Related Art As a device for measuring various kinds of information inside the living body non-invasively without puncturing a living body to be measured with a needle or the like, for example, a device disclosed in Japanese Patent Laid-Open No. 103883/1995 is known. There is. This device irradiates a living body with near-infrared light, detects light (diffuse reflected light) that enters the inside of the living body, repeats transmission and reflection, and again emerges on the surface of the living body, and uses the absorbance calculated from the light intensity. It measures blood glucose in living blood, that is, glucose concentration.
Such a device has the great advantage that it causes less physical pain to the subject.

[0003]

However, it is generally difficult to perform measurement with high accuracy and reproducibility using such a biometric device. Because the subject (the subject's site to be examined) moves due to physiological phenomena or voluntarily, the contact pressure of the light emitting part and the light receiving part with respect to the biological surface fluctuates, and the specular reflection on the biological surface occurs. Is increased, or the state of the scattering coefficient inside the living body is changed.

Further, when the subject is an animal such as a mouse, there is a great possibility that it will move during the measurement,
It is even more difficult to measure with high accuracy and reproducibility. In order to avoid this, it is considered that the movement of the subject is temporarily stopped by a drug or the like, but the action of such a drug may impair the accuracy of the biological information to be originally acquired.

The present invention has been made in view of the above points, and an object thereof is to perform measurement with high accuracy and high reproducibility even when the living body to be measured moves. It is intended to provide a non-invasive living body measuring device that can perform.

[0006]

A non-invasive living body measuring apparatus according to the present invention made to solve the above-mentioned problems includes a) a contact portion that comes into contact with the surface of a living body, and Biometric information acquisition means for measuring information inside the living body, b) pressure detection means for detecting pressure from the living body against the contact portion, and c) depending on the pressure detected by the pressure detection means, the contact portion and / or Alternatively, a moving means for moving the living body is provided.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION When measuring the information inside a target living body using the non-invasive living body measuring apparatus according to the present invention, the contact portion of the living body information acquiring means is pressed against the living body surface. Contact. Then, the pressure detection means detects the pressing force of the living body on the contact portion at that time. The pressure detection means may continuously detect the pressing force including before and after the acquisition of the information via the contact portion, or at least at the timing when the biological information acquisition means acquires the information. It may be one that detects pressure. In any case, the moving means moves at least one of the living body and the contact portion so that the pressure detected by the pressure detecting means becomes a predetermined value. Accordingly, even if the living body moves, the contact pressure of the contact portion with respect to the living body can be kept substantially constant following the movement.

Therefore, according to the non-invasive living body measuring apparatus of the present invention, even if the living body to be measured moves voluntarily or involuntarily, the contact pressure is kept constant to perform highly accurate measurement. be able to. In addition, when the measurement is performed a plurality of times on the same living body, or when the measurement is performed on a plurality of different living bodies, the contact pressure, which is one of the important measurement conditions, can be made the same. High reproducibility can be obtained, and reliability such as comparison of measurement results is significantly improved.

As an embodiment of the non-invasive living body measuring apparatus according to the present invention, the living body information acquiring means is means for optically measuring information inside the living body, and the contact portion emits light toward the living body. It may be configured to include an assembly of optical fibers for emitting and receiving light from the living body.

In this structure, light is irradiated toward the living body from the contact portion in contact with the surface of the living body, and a part of the irradiated light penetrates into the living body and diffuses while passing through the tissue inside the living body. Repeats and reflections, and eventually appears on the surface of the living body.
At this time, the diffuse reflection light emitted from the surface of the living body contains information on the internal tissue of the living body, so this light is received by the contact portion and sent to the main body of the living body information acquisition means via the optical fiber. As a result, it is possible to noninvasively acquire information on the internal tissue of the living body.

Preferably, in the non-invasive living body measuring apparatus according to the present invention, the pressure detecting means detects pressure in three axial directions substantially orthogonal to each other, and the moving means has the contact portion and / or the contact portion. The living body may be moved in the three axis directions.

According to this structure, no matter how the living body moves during the measurement, the contact pressure can be kept constant by following the movement. In addition, when the measurement is performed a plurality of times on the same living body or when the measurement is performed on a plurality of different living bodies, the contact pressure is constant regardless of the initial pressing state of the living body against the contact portion. The measurement can be performed by appropriately adjusting so that Therefore, measurement accuracy and reproducibility are further improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the non-invasive living body measuring apparatus according to the present invention will be described below with reference to FIGS. Figure 1
Is a top view of the measuring unit in the biometric device according to the present embodiment, FIG. 2 is a partial side cross-sectional view of the same measuring unit, FIG. 3 is an operation explanatory diagram of the same measuring unit, and FIG. 2 is a block diagram of an electric system of FIG.

As shown in FIGS. 1 and 2, in the living body measuring apparatus of this embodiment, a stable base 1 is provided with a three-axis moving stage 2 to which a living body holding arm 3 is fixed. The living body holding arm 3 is movable in three axial directions of X, Y and Z which are orthogonal to each other. Further, a pair of shaft fixing pieces 4 are erected on the base 1, and a Z-axis direction moving table 6 is freely movable on a shaft body 5 installed between the shaft fixing pieces 4 (see FIG. 3). Attached (see arrow Mz). The projecting piece 6 at the end of the Z-axis direction moving table 6 located on the opposite side of the shaft body 5.
A Z-axis direction pressure sensor 7 is fixed on the base 1 under a so as to receive a pressing force from above by the protrusion 6a. Accordingly, when a force in the Z-axis direction is applied to the Z-axis direction moving table 6, the force is applied to the Z-axis direction pressure sensor 7.
Detected by.

On the Z-axis direction moving table 6, a Y-axis direction moving table 8 is provided slidably in the Y-axis direction by a pair of linear guides 9 (see arrow My in FIG. 3). In addition, a spring 11 is interposed between the Y-axis moving base 8 and the spring-fixing piece 10 provided upright on the Z-axis moving base 6, and the Y-axis moving base 8 is sandwiched between the spring-fixing pieces. On the side opposite to 10, a Y-axis direction pressure sensor 12 is fixed on the Z-axis direction moving table 6 so as to receive a pressing force for moving the Y-axis direction moving table 8 by the urging force due to the extension of the spring 11. . Accordingly, when a force in the Y-axis direction is applied to the Y-axis direction moving base 8, the force is detected by the Y-axis direction pressure sensor 12.

An X-axis direction moving base 13 is provided on the Y-axis direction moving base 8 so as to be slidable in the X-axis direction by a pair of linear guides 14 (see arrow Mx in FIG. 3). Further, a spring 16 is interposed between the spring fixing piece 15 and the X axis moving table 13 which are erected on the Y axis direction moving table 8, and the spring fixing piece is sandwiched with the X axis direction moving table 13 interposed therebetween. On the side opposite to 15, an X-axis direction pressure sensor 17 is fixed on the Y-axis direction moving table 8 so as to receive a pressing force for moving the X-axis direction moving table 13 by the urging force of the spring 16. . Accordingly, when a force in the X-axis direction is applied to the X-axis direction moving base 13, the force is applied to the X-axis direction pressure sensor 17.
Detected by.

A cylindrical measuring sampler 18 as a contact portion in the present invention is fixed on the X-axis direction moving table 13. The upper surface of the measurement sampler 18 is a contact surface for the subject B, and in order to irradiate the subject B with light and receive diffused reflected light, the irradiation side optical fiber 2
1 and the end surface of the light-receiving side optical fiber 31 are configured to be substantially flush with the contact surface. Specifically, for example, an apparatus proposed by the applicant in Japanese Patent Application No. 2000-328144 can be used. The irradiation-side optical fiber 21 and the reception-side optical fiber 31 are arranged in the X-axis direction moving table 1
3, the Y-axis direction moving base 8 and the Z-axis direction moving base 6 are drawn out from the lower surface of the base 1 so as not to hinder the movement operation of the Y-axis direction moving base 6.

In the biometric apparatus of this embodiment, with the above configuration, the forces applied in the X-axis direction, the Y-axis direction, and the Z-axis direction via the upper surface of the measurement sampler 18, that is, the contact surface, are respectively applied to the X-axis direction pressure sensor. 17, Y-axis direction pressure sensor 12
And the Z-axis direction pressure sensor 7. That is, the force acting in any direction in the space is detected by the three pressure sensors 17, 12, 7.

As shown in FIGS. 2 and 4, the light emitting device 20 is connected to the incident end of the irradiation side optical fiber 21, and the light receiving device 30 is connected to the emission end of the light receiving side optical fiber 31. The light emitting side device 20 includes a light source 22 and a spectroscope 23,
The monochromatic light of a specific wavelength is sent to the irradiation side optical fiber 21. On the other hand, the light-receiving side device 30 includes a photodetector 32, an absorbance calculator 33, and a biological information calculator 34. The light source 22,
The spectroscope 23, the photodetector 32, and the absorbance calculator 33 are substantially infrared spectrophotometers.

In FIG. 4, the light emitted from the light source 22 is introduced into the spectroscope 23, where monochromatic light having a specific wavelength is extracted and irradiated from the measurement sampler 18 toward the subject B through the irradiation side optical fiber 21. It The spectroscope 23 performs wavelength scanning in the range of 1.4 to 1.8 μm, for example. In this wavelength range, the light enters the inside of the subject B by a depth of 0.4 to 1.2 mm, and the light diffusely reflected while passing through the internal tissue is emitted from the subject B. A part of this diffuse reflected light is incident on the incident end face of the light receiving side optical fiber 31 in the measurement sampler 18, and the optical fiber 31
To the photodetector 32. The photodetector 32 outputs an electric signal according to the intensity of the received light, and the absorbance calculator 33 determines the absorbance based on the signal and creates an absorption spectrum showing the relationship between the wavelength and the absorbance. Biometric information calculation unit 3
4 executes a multivariate analysis calculation process based on the absorption spectrum to calculate desired biometric information. For example, glucose concentration in blood can be obtained as the biometric information, but other biometric information may be used.

At the time of the above measurement, the subject B, which is a living body, is placed on the upper surface of the living body holding arm 3. When the living body holding arm 3 and the measurement sampler 18 are in an appropriate position (height) relationship, as shown in FIG. 2, the lower surface of the subject B comes into contact with the upper end surface of the measurement sampler 18 with an appropriate pressure. It is pressed. In that state, when light is irradiated from below as described above, the light penetrates into the inside of the subject B, and the light diffusely reflected by the internal tissue returns to the measurement sampler 18. If the subject B moves during such one measurement or in the middle of repeated measurements, the contact pressure of the subject B to the measurement sampler 18 changes, and the amount of reflected light on the surface of the subject B changes accordingly. And the scattering coefficient and the like inside the subject B vary. Such a variation is an error irrelevant to the original value of biometric information. Therefore, in the biometric device of the present embodiment, 3
Pressure sensors 17, 12, 7 and these pressure sensors 1
The control unit 40 that reads the detected pressure by 7, 12, 7 and 3
The axis moving stage 2 functions as follows.

That is, the pressure detected by the three pressure sensors 17 and 7 for detecting the pressing force in the three axial directions of X, Y, and Z is controlled at least during the measurement of the subject B. It is input to the section 40. When the pressing force of the subject B against the measurement sampler 18 does not change at all, the pressures detected by these pressure sensors 17, 12, 7 are constant, but when the subject B moves, the magnitude and direction of the movement. Changes the detected pressure. Therefore, the control unit 40 compares each of the read three detected pressures with a predetermined target value, and calculates a control signal such that the difference between the two is zero.

Specifically, for example, the three-axis moving stage 2 has pulse motors independent in the three-axis directions, and the control unit 40 calculates the number of pulses for driving each pulse motor as a control signal. To do. Then, the number of pulse signals corresponding to the number of pulses is sent to each motor. For example, when the pressure detected by the Z-axis direction pressure sensor 7 falls below a target value, in order to increase the pressing force of the subject B, the living body holding arm 3 is lowered by a predetermined distance on the Z-axis by three axes. Control the moving stage 2. As a result, the pressing force from the subject B on the measurement sampler 18 is increased. On the contrary, when the pressure detected by the Z-axis direction pressure sensor 7 exceeds the target value, in order to decrease the pressing force of the subject B, the living body holding arm 3 is raised by a predetermined distance on the Z-axis by three axes. Control the moving stage 2. This allows
The pressing force from the subject B on the measurement sampler 18 is weakened.

Also in the X-axis direction and the Y-axis direction, similarly, the living body holding arm 3 is moved in three axes so as to move the living body holding arm 3 on the X-axis and the Y-axis by a predetermined distance so that each detected pressure becomes a target value. Control stage 2. 3 pressure sensors 1
Since the forces applied to the measurement sampler 18 in the three-axis directions are detected by 7, 12, and 7, the living body holding arm 3 can be moved in any direction in the space by the three-axis moving stage. The contact pressure can be maintained substantially constant by following any movement of the subject B. Moreover, when measuring the same or different test object B, the same contact pressure can always be reproduced and measured.

It should be noted that the above embodiment is merely an example of the present invention, and it is obvious that various forms and configurations can be modified and modified within the scope of the claims of the present application.
For example, instead of moving the living body holding arm 3 that supports the subject B, the measurement sampler 18 itself may be moved.

[Brief description of drawings]

FIG. 1 is a top view of a measuring unit in a biometric device according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional side view of the measuring section of FIG.

FIG. 3 is an explanatory diagram of the operation of the measuring unit in FIG.

FIG. 4 is a block diagram of an electrical system of the biometric device according to the present embodiment.

[Explanation of symbols]

1 ... Base 2 ... 3-axis movement stage 3 ... Living body holding arm 4 ... Shaft fixing piece 5 ... Shaft 6 ... Z-axis movement base 6a ... Protrusion 7 ... Z-axis direction pressure sensor 8 ... Y-axis direction moving table 9, 14 ... Linear guide 10, 15 ... Spring fixing pieces 11, 16 ... Spring 12 ... Y-axis direction pressure sensor 13 ... X-axis direction moving table 17 ... X-axis direction pressure sensor 18 ... Measurement sampler 20 ... Light emitting side device 21 ... Irradiation side optical fiber 22 ... Light source 23 ... Spectrometer 30 ... Receiving side device 31 ... Receiving side optical fiber 32 ... Photodetector 33 ... Absorbance calculation unit 34 ... Biometric information calculation unit 40 ... Control unit B ... Subject

Claims (3)

[Claims] 1. A) including a contact portion that contacts a surface of a living body,
Biometric information acquisition means for measuring information inside the living body via the contact portion, b) pressure detection means for detecting pressure from the living body on the contact portion, and c) depending on pressure detected by the pressure detection means. And a moving means for moving the contact portion and / or the living body, the non-invasive living body measuring apparatus. 2. The biological information acquisition means is means for optically measuring information inside the living body, and the contact portion emits light toward the living body and receives light from the living body. The non-invasive living body measuring apparatus according to claim 1, further comprising an assembly of fibers. 3. The pressure detecting means are substantially orthogonal to each other.
The non-invasive living body according to claim 1 or 2, wherein the moving means detects axial pressure and the moving means moves the contact portion and / or the living body in the three axial directions. Measuring device.