JP3543463B2 - Biological signal detection device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a biological signal detecting device for detecting heartbeat, respiration, body movement, etc. of a living body without restriction, and more particularly to a biological signal detecting device using an optical fiber.
[0002]
[Prior art]
In the detection of various biological signals, the type that attaches a sensor unit to the living body restricts the movement of the living body and also detects the biological signal in a relaxed state because this constraint applies stress to the living body However, various types of non-restrained types have been proposed, especially when the electrodes are attached to the skin, because the skin may become rough or irritated. A flexible optical fiber having the other end connected to the light receiving unit is arranged along the living body supporting surface of the living body supporting unit for receiving a living body, and the light guided from the light emitting unit to the light receiving unit by the optical fiber is connected to the light emitting unit. There is a method that captures a load variation by changing an amount by bending of an optical fiber accompanying a variation in a biological load, and detects a biological signal therefrom.
[0003]
That is, as shown in FIG. 6, one end is connected to the light-emitting element 3a such as a light-emitting diode, and the other end is connected to the light-receiving element 3b, to the living body support 2 (in FIG. 6, the backrest of a chair) for receiving the living body 9. The optical fiber 1 is arranged so that the optical fiber 1 bends when a load on the living body 9 is applied, and the light receiving element 3b is detected via a converter 30 for converting the current output to a voltage and an amplifier 31. The unit 32 is connected. The detection unit 32 has a discrimination unit 33 including a low-pass filter, a comparator, and the like, and detects a biological signal such as body movement, respiration, or heartbeat.
[0004]
In this type, since it is not attached to the human body and uses a flexible optical fiber, it can be made not to irritate the living body, and it does not have an electromagnetic effect on the living body, and It has the advantage that high sensitivity can be expected for biological signals.
From the point of sensitivity, it is difficult to detect even a slight change in load due to heartbeat by simply arranging an optical fiber on the living body support. Therefore, as shown in FIG. It has been proposed that an optical fiber 1 to be bent is bent in a direction having a required curvature in a direction in which a load of a living body is applied. If the optical fiber 1 is bent so as to have a required curvature in the direction in which the load of the living body is applied, the bent portion of the optical fiber 1 will have an amount of light reaching the light receiving unit with a change in the load (pressure) applied from the living body. Since the curvature is changed in a curvature region where is greatly changed, high sensitivity can be obtained.
[0005]
That is, the optical fiber is composed of a core and a clad surrounding the core, and guides the light from the light emitting portion to the light receiving portion by total reflection at the boundary surface between the core and the clad. Not all light is totally reflected on the surface but some light is transmitted through the cladding. At this time, in the curvature region where the total reflection angle can be maintained for most of the light because the curvature of bending is small, the change in the amount of light reaching the light receiving portion even when the optical fiber is bent is small. . However, in a curvature region in which the total reflection angle cannot be maintained with respect to a large amount of light even if a slight bending is caused, the amount of light reaching the light receiving portion changes greatly with the bending. In addition, when the optical fiber has the above-mentioned curvature in the direction in which the load of the living body is applied, the optical fiber is surely bent even with a small change in load, so that the amount of light reaching the light receiving portion changes significantly without fail. This means that high sensitivity can be obtained.
[0006]
[Problems to be solved by the invention]
However, since the optical fiber is easily broken, the following points are problematic. That is, since the optical fiber is arranged in a place where a biological load is applied, if the strength of the optical fiber is considered, the load must be dispersed by increasing the number of load points. For this reason, in the above-described support member shown in FIG. 7, one surface is a surface to which a load from the living body 9 is applied, and the other surface has an uneven portion 70. The support member 7b, which is in a state of being floating with respect to the support member 7a, passes through the optical fiber 1 between the support member 7a and the support member 7a having the concave-convex portion 70 on the side facing the surface, and receives the load of the living body, and When the optical fiber 1 is pushed by the concave and convex portions 70 when the optical fiber 1 is moved, and the optical fiber 1 is bent in the direction in which the load of the living body is applied, a plurality of the concave and convex portions 70 are provided in the longitudinal direction of the optical fiber 1, and the point of transmission of the load to the optical fiber 1. As shown in FIG. 8, the number of load points is increased by folding the optical fiber 1 and passing the optical fiber 1 between the support members 7b and 7a a plurality of times as shown in FIG. .
[0007]
Here, even if the optical fiber 1 has flexibility, the radius of curvature that does not cause breakage is considerably large, and therefore, the number of bent portions when the plurality of uneven portions 70 are bent in a wave shape is large. That the number of load points must be increased by providing a turn-up and a turn-up, which means that the entire area including the turn-up portion of the optical fiber 1 becomes large, and there are restrictions in terms of mounting structure and cost. More.
[0008]
The present invention has been made in view of such a point, and an object of the present invention is to provide a biosignal detection device which is compact and has a small mounting structure and few restrictions on cost in a high sensitivity using an optical fiber. is there.
[0009]
[Means for Solving the Problems]
Thus, the present invention reduces the amount of light reaching the light receiving portion by bending an optical fiber disposed on the living body supporting portion receiving the living body and guiding the light from the light emitting portion to the light receiving portion by a change in the biological load applied to the living body supporting portion. In a biological signal detection device that changes and detects a biological signal from the output of the light receiving unit at this time, the biological signal detecting device includes a load sharing member that contacts a supporting member for transmitting the biological load to the optical fiber and shares the biological load applied to the supporting member. In addition, the above-mentioned load-sharing members, which are only responsible for load-sharing, are characterized in that they are evenly arranged on both sides of the optical fiber . ADVANTAGE OF THE INVENTION According to this invention, since the load sharing member equally distribute | arranged on both sides of an optical fiber receives a living body load and receives it, the load applied to an optical fiber itself can be reduced.
[0010]
If the load sharing member has substantially the same hardness as the optical fiber, for example, an optical fiber, the design calculation of the load applied to the optical fiber through which light passes becomes easy.
In addition, it is preferable that the support member has a stopper that limits a biological load transmitted to the optical fiber and the load sharing member to a predetermined value in order to prevent breakage of the optical fiber due to an excessive load, and a positional relationship between the optical fiber and the load sharing member. It is also preferable to provide the support member with a position shift preventing portion for preventing the shift of the position from the viewpoint of stable load detection.
[0011]
If the portion of the optical fiber that is affected by the biological load and the end connected to the light-emitting portion and the light-receiving portion are arranged in a close position and in a fixed positional relationship, the point of noise reduction due to the optical fiber itself can be reduced. Is preferred.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
An example of an embodiment of the present invention will be described. The system is the same as that shown in FIG. 6, and a supporting member 7b which is a member that receives a biological load and has an uneven portion 70 on the opposing surface. , 7a, the optical fiber 1 is bent with a required curvature in the direction in which the load of the living body is applied, in the same manner as described above, but as shown in FIGS. The optical fiber 1 is passed only once between the support members 7b and 7a. Then, rod-shaped (linear) and flexible load sharing members 5 and 5 are arranged at equal distances from the optical fiber 1 on both sides of the optical fiber 1 positioned at the center in the width direction of the support members 7b and 7a. is there. In the illustrated example, two load sharing members 5, 5 are provided, but the number is not limited to this.
[0013]
The load-sharing members 5, 5 having substantially the same hardness and flexibility as the optical fiber 1 and disposed between the two support members 7b, 7a are provided when a biological load is applied to the living body supporting surface, which is the surface of the support member 7b. The load on the optical fiber 1 is reduced by carrying a part of the biological load, thereby preventing the optical fiber 1 from being damaged. In the figure, reference numeral 71 denotes a groove provided in the uneven portion 70 in order to prevent the optical fiber 1 and the load sharing members 5 and 5 from being displaced.
[0014]
If the load sharing members 5 and 5 have the same diameter as the optical fiber 1 and have the same characteristics as the optical fiber 1, it is easy to calculate the stress applied to the optical fiber 1 for transmitting a signal, and the length of the load sharing member 5 can be reduced. Although it is easy to determine items related to the number of load points such as sheaths and the arrangement position, etc., it is needless to say that the optical fiber 1 may be made of a material having no limitation on the curvature such as the optical fiber 1. . When the former specification is adopted as the load sharing member 5, the load sharing member 5 may be formed of the same optical fiber as the optical fiber 1 that transmits the signal detection light. However, the optical fiber used as the load sharing member 5 does not transmit the signal detection light, and is used only for load sharing. In the case of adopting the latter specification, the load sharing member 5 does not have to be in the shape of a rod, but may be in the form of a sheet or a lump disposed at a position other than the portion where the optical fiber 1 is disposed.
[0015]
The load sharing members 5 and 5 are arranged at the same distance from the optical fiber 1 so as to be parallel to the optical fiber 1 even if a load is applied only to the right end or the left end in FIG. 2B. This is because good signal detection can be performed. In this regard, it is most preferable that the load sharing members 5 and 5 are disposed at the left and right ends of the support members 7b and 7a.
[0016]
The stopper shown in FIG. 3 is provided on the support member 7b to limit the mutual approach of the support members 7b and 7a in order to prevent the optical fiber 1 from being damaged when an excessive load is applied. Further, the one shown in FIG. 4 prevents a lateral displacement between the support members 7b and 7a from occurring by passing a boss 74 projecting from the support member 7b through a hole 75 provided on the support member 7a side. By screwing a screw 76 having a head with a diameter larger than the diameter of the support member 7 into the tip of the boss 74, the support members 7b and 7a are prevented from being separated from each other.
[0017]
By the way, a light emitting element and a light receiving element are connected to both ends of the optical fiber 1, and the above-mentioned circuit is further connected to the light receiving element. As shown in FIG. 5, it is desirable to dispose and fix in a state where it is adjacent to the support member 7a and the positional relationship with the support member 7a does not change. From the portion of the optical fiber 1 sandwiched between the support members 7b and 7a to the portion connected to the substrate 6 by the optical connector 60, the shape of the portion bent in an arc in the drawing can be kept constant. This is because it is possible to prevent the influence of the bending deformation from appearing in the detection of the original minute change in the biological load at the portion sandwiched between the support members 7b and 7a.
[0018]
【The invention's effect】
As described above, in the present invention, since the load sharing member is provided in contact with the support member for transmitting the biological load to the optical fiber and shares the biological load applied to the support member, the biological load is shared by the load sharing member. The load applied to the optical fiber itself can be reduced, so that even if the number of load points on the optical fiber is reduced, the optical fiber will not be damaged, and therefore, it is compact and has less restrictions on the mounting structure and cost. be able to. In addition, since the load sharing members are evenly arranged on both sides of the optical fiber, the transmission of the load to the optical fiber can be ensured regardless of the load position even if the number of load points is small.
[0019]
If the load sharing member is made of a material having substantially the same hardness as the optical fiber, for example, an optical fiber, the design calculation of the load applied to the optical fiber through which light passes to detect a biological signal from the change in load becomes easy.
[0020]
Further, if a stopper is provided on the support member for limiting the biological load transmitted to the optical fiber and the load sharing member to a predetermined value, breakage of the optical fiber due to an excessive load can be reliably prevented, and the optical fiber and the load sharing member can be prevented from being damaged. If a displacement prevention part for preventing displacement of the positional relationship is provided on the support member, stable load detection can be performed.
[0021]
In addition, if the portion of the optical fiber that is affected by the biological load and the ends connected to the light-emitting unit and the light-receiving unit are arranged in a close position and in a fixed positional relationship, noise due to the optical fiber itself is reduced. And stable biological signal detection can be performed.
[Brief description of the drawings]
FIG. 1 is a perspective view of an example of an embodiment of the present invention.
FIGS. 2 (a) and 2 (b) are a front view and a sectional view of the same.
FIG. 3 is a sectional view of another example of the above.
FIG. 4 is a sectional view of still another example of the above.
FIG. 5 is a sectional view of another example of the above.
FIG. 6 is a block diagram illustrating an example of a biological signal detection device using an optical fiber.
FIG. 7 is a sectional view of the same.
FIG. 8 is a front view of the same.
[Explanation of symbols]
1 Optical Fiber 5 Load Sharing Member 7a Support Member 7b Support Member

Claims (6)

The optical fiber, which is disposed on the living body support for receiving the living body and guides the light from the light emitting unit to the light receiving unit, is bent by the change in the biological load applied to the living body supporting unit to change the amount of light reaching the light receiving unit. In a biological signal detection device that detects a biological signal from a light receiving unit output, a load sharing member that contacts a supporting member for transmitting a biological load to an optical fiber and shares a biological load applied to the supporting member is provided, and only the load sharing is performed. The biological signal detecting device according to claim 1, wherein said load sharing members are equally arranged on both sides of said optical fiber . 2. The biological signal detecting device according to claim 1, wherein the load sharing member has substantially the same hardness as the optical fiber . The biological signal detection device according to claim 2, wherein the load sharing member is formed of an optical fiber . The biological signal detecting device according to claim 1, wherein the support member includes a stopper that limits a biological load transmitted to the optical fiber and the load sharing member to a predetermined value . 2. The biological signal detecting device according to claim 1, wherein the support member includes a position shift prevention unit that prevents a shift in a positional relationship between the optical fiber and the load sharing member . 2. The biological signal according to claim 1, wherein a portion of the optical fiber that is affected by a biological load and an end connected to the light emitting unit and the light receiving unit are arranged in a close position and in a fixed positional relationship. Detection device.

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