JP2001087249A - Blood component measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance measuring accuracy more than usual in a device for measuring a blood component by detecting a light beam passing through a blood vessel by irradiating the beam to the blood vessel in a living body. SOLUTION: This blood component measuring device comprises a device body 1 having a guide block for fixing a fingertip, two CCD cameras 5, 7 for detecting a position of a blood vessel in the fingertip, a light source 8 for emitting a beam of light toward the fingertip and a light detector 9 for detecting the light passing through the fingertip, where the light source 8 and the light detector 9 can be positioned so that the optical axis penetrates through a blood vessel position by a positioning mechanism, and a blood component is measured on the basis of a detecting signal from the light detector 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring components such as glucose and cholesterol contained in blood by irradiating blood vessels in a living body with light and detecting light transmitted through the blood vessels. is there.

[0002]

2. Description of the Related Art In this type of blood component measuring device,
As shown in FIG. 9, a light source (80) and a photodetector (90) are provided opposite to each other with the fingertip F interposed therebetween, and near-infrared light is emitted from the light source (80) toward the fingertip F. The light transmitted through F is detected by a photodetector (9
0), and analyzing components such as wavelengths of transmitted light to measure components in blood.
(JP-A-5-176917, JP-A-10-190, JP-A-10-78437
No., JP-A-10-216112, JP-A-11-137538, etc.).

[0003] As shown in FIG. 9, all of the conventional blood component measuring devices are arranged in a direction orthogonal to the longitudinal axis of the fingertip F.
The light having a spot diameter much larger than the diameter of the blood vessel is transmitted, thereby ensuring that the light from the light source (80) passes through the blood vessel G.

[0004]

However, in a conventional blood component measuring apparatus, light having a spot diameter much larger than the thickness of a blood vessel is irradiated on a fingertip, and a blood component is measured based on the transmitted light. As a result, a large amount of light is transmitted not only to the blood vessel G but also to surrounding tissues such as fat and muscle. As a result, the measured values of the blood vessel components include the component values of tissues other than blood such as fat. Was included, and there was a problem that the measurement accuracy was poor. Conventionally, there is no known device that detects the position of a blood vessel at a specific site and irradiates the position with light to measure blood components.

The light emitted from the light source (80) is
Penetrates the fingertip in the direction substantially perpendicular to the longitudinal axis of the blood vessel G, ie, the direction in which the blood vessel G extends. As a result, similarly to the above, the measured value of the blood vessel component includes the component value of tissue other than blood, which causes a decrease in measurement accuracy.

An object of the present invention is to provide a blood component measuring device capable of obtaining a measured value with higher accuracy than before.

[0007]

A blood component measuring apparatus according to the present invention comprises a fixing mechanism for fixing a part of a living body at a predetermined position, and a detecting means for detecting a position of a blood vessel in the part fixed to the fixing mechanism. Means, a light source that emits a light beam toward the site, a photodetector that detects light transmitted through the site, and light such that an optical axis from the light source to the photodetector passes through the blood vessel position. Positioning means for adjusting the position of the shaft;
Analyzing means for analyzing a blood component based on a detection signal from the photodetector.

In the blood component measuring device of the present invention, the position of the optical axis from the light source to the photodetector is adjusted with respect to the part fixed to the fixing mechanism, and the position of the blood vessel in the part is adjusted by the light source. Therefore, even if the spot diameter of the light beam emitted from the light source is made smaller than before, the light beam can be reliably applied to the blood vessel.

Accordingly, most of the light emitted from the light source passes through the blood vessel, and only a small amount of light passes through tissues such as fat and muscle existing around the blood vessel. Therefore, the measured value of the blood vessel component contains little component value of tissue other than blood, and is highly accurate.

In a specific configuration of the present invention, the means for detecting a blood vessel position includes means for photographing a blood vessel image of a portion fixed to a fixing mechanism, and a density of blood vessels in the portion based on the photographed blood vessel image. Means for detecting the position where the maximum value is obtained as the blood vessel position.

In this specific configuration, even when a site where thin blood vessels are distributed at narrow intervals, such as a fingertip, is to be measured, a position where the density of blood vessels is maximum is determined as a blood vessel position. Since the light is irradiated, high measurement accuracy can be obtained.

Further, in a specific configuration according to the present invention, the fixing mechanism fixes the fingertip, and the light source and the photodetector are arranged to face each other along the longitudinal axis of the fingertip fixed to the fixing mechanism. ing. For example, the fixing mechanism includes a guide for fixing the finger in a state where the finger is bent at the second joint,
Light from the light source penetrates the fingertip from the tip of the finger to the second joint or vice versa.

In the specific configuration, the light beam enters, for example, from the tip of a finger and penetrates the fingertip along the longitudinal axis, that is, along the direction in which the blood vessels extend. Therefore, rather than the length of the light path that passes through tissues such as fat and muscle,
The length of the light path that penetrates the blood vessels increases, and as a result,
The measured value of the blood vessel component hardly contains the component value of the tissue other than the blood, and is more accurate.

[0014]

According to the blood component measuring apparatus according to the present invention, it is possible to obtain a measured value with higher accuracy than before.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. A blood component measuring device according to the present invention measures a blood component with a fingertip as a target portion, and as shown in FIGS. 1 to 4, a guide for fixing a finger in a state of being bent at a second joint. block
First and second light sources (4) and (6) and first and second light sources (4) and (6) for capturing a blood vessel image of a fingertip F are provided on an apparatus main body (1) including (10).
And a third light source (8) and a photodetector (9) for measuring blood components.

The guide block (10) has a finger guide groove (11) for guiding a portion closer to the base of the finger than the second joint, and a fingertip guide for guiding a portion (fingertip) beyond the second joint. groove
A fingertip fixing member (15) for fixing the fingertip F to the fingertip guide groove (12) is provided at the opening edge of the fingertip guide groove (12) so as to be openable and closable. Have been.

The above-mentioned first light source (4) and first CCD camera
(5) are provided on opposite sides of the fingertip along an axis perpendicular to the longitudinal axis (vertical axis in the figure) of the fingertip fixed to the fingertip guide groove (12), and are respectively provided on the device body ( It is fixed inside 1). Also, the second light source (6) and the second CCD described above.
The camera (7) includes a first light source (4) and a first CCD camera (5).
Are disposed on both sides of the fingertip along an axis intersecting at an angle difference of 90 ° with the opposite axis, and are respectively fixed inside the apparatus main body (1). The third light source (8) and the photodetector (9) described above are provided on both sides of the fingertip along the longitudinal axis of the fingertip fixed to the fingertip guide groove (12). (1) is supported via a positioning mechanism (2).

The first to third light sources (4), (6) and (8) emit near-infrared light, respectively, and the first and second light sources (4) and (6) The emitted light beam is relatively thick and each CC
With the D cameras (5) and (7), a blood vessel image of the entire fingertip can be taken. On the other hand, the light beam emitted from the third light source (8) is thinner than the thickness of the fingertip and irradiates the blood vessel position of the fingertip intensively.

As shown in FIGS. 1 and 2, the positioning mechanism (2) includes a first slide plate (24) slidably supported on the upper surface of the apparatus main body (1) along the X-axis direction. The first motor (22) is connected via a one-ball screw mechanism (23), and the second slide plate (27) slidably supported on the first slide plate (24) along the Y-axis direction. ), The second ball screw mechanism (26)
And a second motor (25) connected thereto. The second slide plate (27) has a U-shaped frame (21) extending from the upper surface to the lower surface via the side surface of the device main body (1). The proximal end is connected. Then, a photodetector is provided on the back surface of the second slide plate (27).
(9) is fixed and the third end is attached to the tip of the frame (21).
The light source (8) is fixed.

Therefore, while the first slide plate (24) is reciprocated in the X-axis direction by driving the first motor (22),
By driving the motor (25) to reciprocate the second slide plate (27) in the Y-axis direction, the third light source (8) and the photodetector (9) can be moved to arbitrary positions on the (XY) plane. Can be positioned.

As shown in FIG. 3, the apparatus body (1) includes:
A light source window (13) is opened at a position corresponding to the third light source (8), and a light detection window (14) is opened at a position facing the light detector (9). The light beam emitted from (1) enters the light detector (9) through the light source window (13), the fingertip guide groove (12) and the light detection window (14).

FIG. 6 shows the configuration of a control system of the blood component measuring device according to the present invention. The above three light sources (4)
(6) (8), two CCD cameras (5) (7), and a photodetector
(9) is connected to the microcomputer (3) and emits light beams from the light sources (4), (6) and (8), and the CCD cameras (5)
The capture of the image from (7) and the capture of the detection signal from the photodetector (9) are controlled.

The positioning mechanism (2) is connected to the microcomputer (3), and the rotation of two motors (22) and (25) constituting the positioning mechanism (2) is controlled. The microcomputer (3) is composed of two C
Based on the images from the CD cameras (5) and (7), the position of the highest blood vessel density at the fingertip is detected, and based on the detection, the positioning mechanism (2) is controlled, and the third light source (8) and light detection are performed. vessel
Perform the positioning of (9). The microcomputer (3) analyzes the blood components based on the signal from the photodetector (9) by a known method.

Further, the microcomputer (3) includes an output device (16) comprising a display, a printer and the like.
Is connected, so that the measurement result of the blood component can be output.

FIG. 7 shows a procedure for measuring blood components using the blood component measuring apparatus. In the blood component measurement procedure described later, the position of the blood vessel at the fingertip is grasped as three-dimensional data. The three-dimensional position of the blood vessel is assumed to have a circular cross-sectional shape of the blood vessel G as shown in FIG. Then, the three-dimensional coordinates (x, y,
z) and four position data of the radius r of the outer circumference circle.
For example, assuming that the leading end position of the fingertip guide groove (12) is the origin O as shown in the figure, the arbitrary point A of the blood vessel G is represented by four position data.
It is represented by (x, y, z, r). And one blood vessel G
About position data at regular intervals in its longitudinal direction
When (x, y, z, r) is held and the blood vessel position is referred to, the space between the points is complemented and converted to a continuum.

In measuring the blood vessel component, first, the main body of the apparatus
A finger is placed on the guide block (10) of (1), and the fingertip is fixed to the fingertip guide groove (12) by the fingertip fixing member (15) while the finger is bent at the second joint (step S1). On this occasion,
The fingertip is guided by the fingertip guide groove (12) so that its longitudinal axis is perpendicular to the X axis and the Y axis.
The direction is set to be substantially parallel to the axis.

Next, the first light source (4) is turned on (step S).
2), the blood vessel at the fingertip is photographed by the first CCD camera (5) (step S3). After that, the second light source (6) is turned on.
(Step S4) The second CCD camera 7 photographs the blood vessel at the fingertip. Thus, a blood vessel image V as shown in FIG. 8A is obtained from each CCD camera.

Thereafter, the three-dimensional position of the blood vessel is calculated based on the blood vessel images obtained from the two CCD cameras (5) and (7).
(Step S6). Then, the volume occupied by the blood vessel in the longitudinal axis of the fingertip is calculated from the three-dimensional position of the blood vessel. For example, FIG.
In the case of the blood vessel image V shown in (a), the three-dimensional position of the blood vessel is divided into a large number of regions extending in the Z-axis direction as shown by the broken lines, as shown in FIG. Calculate the occupied volume density. From the distribution W of the volume density of the blood vessels in these regions, as shown in FIG.
ax) is obtained as position data (x, y).

At the maximum position of the blood vessel density obtained as described above, it is considered that a relatively thick blood vessel extends in the Z-axis direction or a plurality of blood vessels extend in the Z-axis direction at close intervals. Therefore, the blood vessel is determined as a blood component measurement target (step S7). Then, based on the position data (x, y) of the blood vessel determined as the measurement object, the positioning mechanism (2) is operated, and as shown in FIG.
The optical axis C of (8) and the photodetector (9) is adjusted to the blood vessel position (x, y) (step S8).

Next, the living body (fingertip F) is irradiated with light from the third light source (8), and the transmitted light is detected by the photodetector (9).
(Step S9). At this time, the light from the third light source (8) penetrates the blood vessel extending in the longitudinal axis of the fingertip in the longitudinal direction, and a long optical path length is formed in the blood vessel.

The detection signal from the photodetector (9) is sent to the microcomputer (3), and the components of the blood are analyzed based on the detection signal, and components such as glucose and cholesterol are calculated ( Step S10). The calculated component is output by the output device (16) shown in FIG.

As described above, according to the blood component measuring apparatus of the present invention, the position where the blood vessel density is highest in the fingertip is detected based on the blood vessel image of the fingertip, and the light beam is accurately irradiated to the position. Therefore, a highly accurate measurement value that hardly includes an error due to tissues such as fat and muscle existing around the blood vessel can be obtained. In addition, since the light beam is irradiated on the longitudinal axis of the fingertip, the light beam penetrates a blood vessel extending in the fingertip along the longitudinal axis with a long optical path length, thereby obtaining higher measurement accuracy.

The configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims. For example, the target of blood component measurement is not limited to a fingertip, and measurement can be performed on a leg or arm. In this case, a guide block may be formed according to the shape of the target.

[Brief description of the drawings]

FIG. 1 is a perspective view of a blood component measurement device according to the present invention as viewed obliquely from below.

FIG. 2 is a perspective view of the device as viewed obliquely from above.

FIG. 3 is a perspective view showing an arrangement of a light source, a CCD camera, and a photodetector in the device.

FIG. 4 shows a light source and a CCD for a fingertip fixed to the apparatus.
It is a perspective view showing the positional relationship of a camera and a photodetector.

FIG. 5 is a diagram illustrating a method of expressing a three-dimensional position of a blood vessel.

FIG. 6 is a block diagram illustrating a configuration of a control system of the blood component measurement device of the present invention.

FIG. 7 is a flowchart showing a procedure of blood component measurement using the device.

FIG. 8 is a series of diagrams illustrating a method of specifying a blood vessel position in the device.

FIG. 9 is a diagram showing a basic configuration of a conventional blood component measuring device.

[Explanation of symbols]

 (1) Device body (10) Guide block (11) Finger guide groove (12) Fingertip guide groove (2) Positioning mechanism (21) Frame (22) First motor (23) First ball screw mechanism (24) First 1 slide plate (25) 2nd motor (26) 2nd ball screw mechanism (27) 2nd slide plate (3) Microcomputer

Claims (4)

[Claims] An apparatus for measuring a blood component by irradiating a blood vessel in a living body with a light beam and detecting a light beam transmitted through the blood vessel, comprising: a fixing mechanism for fixing one part of the living body at a predetermined position; Detecting means for detecting a position of a blood vessel in a portion fixed to the fixing mechanism; a light source for emitting light toward the portion; a light detector for detecting light transmitted through the portion; and light detection from the light source Positioning means for adjusting the position of the optical axis so that the optical axis reaching the blood vessel passes through the blood vessel position, and analyzing means for analyzing a blood component based on a detection signal from the photodetector. Characteristic blood component measuring device. 2. The blood vessel position detecting means includes: means for photographing a blood vessel image of a part fixed to a fixing mechanism; and a position at which the density of blood vessels in the part is maximized based on the photographed blood vessel image. The blood component measuring device according to claim 1, further comprising means for detecting the position of a blood vessel. 3. The fixing mechanism for fixing a fingertip, wherein the light source and the photodetector are provided to face each other along a longitudinal axis of the fingertip fixed to the fixing mechanism. The blood component measuring device according to claim 1. 4. The fixing mechanism includes a guide for fixing the finger in a state where the finger is bent at the second joint, and a light beam from the light source passes through the fingertip from the tip of the finger to the second joint or in the opposite direction. The blood component measuring device according to claim 3.