JPH062655Y2 - Electrode for EEG measurement - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an electrode for measuring an electroencephalogram for detecting an action potential of the brain.

2. Description of the Related Art In a medical device that measures a weak signal due to an action potential of a living body, etc. Widely used in electroretinograms.

In the case of bioelectrical measurement of brain waves, in addition to a means of measuring spontaneous brain waves due to brain activity, there is a clinical practice of applying external stimuli to induce action potentials in the brain due to disturbance, and measuring this evoked potential to measure brain waves. It is popular. As a means of external stimulation,
For example, various things such as flash stimulation, sound stimulation, carotid artery compression and drug administration are known. These clinical examination methods are used for diagnosing epilepsy, brain tumor, cerebrovascular injury, cerebral inflammation (meningitis, encephalitis, etc.), and various endocrine injuries, and are also extremely common clinical examinations in the field of psychiatry. Known as a technique.

Further, an electrode as a lead-out end for detecting a weak electroencephalogram is required to have electrical stability, and silver or a mixture of silver and silver chloride is often used as an electrode material.

By the way, in the case of a silver electrode, it cannot be used as it is because of a high offset voltage, and it is necessary to subject the surface to chlorination by immersing it in a physiological saline solution.

For mixed electrodes of silver and silver chloride, porous green compacts are used for high performance, but in clinical practice, conductive paste is used for electrical connection between the scalp and electrodes. Is applied. That is, when this conductive paste passes through the inside of the green compact and reaches the lead wire connecting portion on the back surface of the electrode, a local battery is generated to electrochemically elute the lead wire material. Because this electrochemical reaction is recorded as noise,
In some cases, highly accurate signal detection may not be possible.

Based on the above circumstances, the electrodes proposed are:
For example, JP-A-63-13 developed by the applicant of the present application.
There are numerous proposals, including the 2632 publication. These techniques have been proposed on condition that they have the following electrical characteristics in order to derive a weak voltage of a living body as an electrode element in contact with the skin. That is, it has a low electrical resistance value, has excellent corrosion resistance, and can suppress electrochemical changes.

Problems to be Solved by the Invention With regard to these three conditions, the targets can be almost achieved by the numerous proposals mentioned above. However, the following problems remain to be solved.

That is, regardless of whether the electrode is a silver electrode or a mixed electrode of silver and silver chloride, it is necessary to perform resin molding on the outside for electrode protection, and the manufacturing cost rises because the structure is complicated. is there.

Therefore, under such circumstances, the current situation is that the electrode is repeatedly used for many patients. As a result, there is a risk that patients with skin injuries such as infectious diseases may be hindered,
In some cases, it may interfere with the prevention of infection such as hepatitis B and AIDS (AIDS). Therefore, as this type of electrode, it is desired that the electrode used for each patient be disposable.

In view of the above situation, the present invention eliminates the complexity of using a silver electrode, solves the problem of the characteristics of the mixed electrode, and particularly the cost increase of the latter mixed electrode. It is an object of the present invention to solve the problems and provide a disposable electroencephalogram measurement electrode capable of high performance and cost reduction.

An electrode for measuring an electroencephalogram according to the present invention comprises a resin electrode element having a head having a flange and a slit and having a conductive coating formed on the surface, and the electrode element is covered from the head side. Including an insulating protective case to be housed in and a lead wire connected to the head of the electrode element and led out from the protective case, the electrode element is elastically coupled to the protective case via a flange. It is a composition.

The resin-made electrode element having a conductive film formed on its surface is housed from the head side thereof while being covered with an insulating protective case.
A lead wire is led out to the protective case, and the lead wire is welded to the head of the electrode element in the protective case.

By assembly, the welded joint is sealed from below in the protective case by the flange of the electrode element. Filling the inner space of the protective case with a conductive paste can suppress the generation of noise as in the conventional case.

Example Hereinafter, an example of an electrode for measuring an electroencephalogram according to the present invention will be described with reference to the drawings.

The outline of the structure of this electrode is, as shown in the figure, a resin-made electrode element having a flange and a head having a slit and having a conductive coating formed on the surface, and the electrode element is covered from the head side and accommodated. The insulating element includes an insulating protective case and a lead wire connected to the head of the electrode element and led out of the protective case, and the electrode element is elastically fitted to the protective case via a flange.

2 and 3 are a plan view and a sectional view of the electrode element 10. The electrode element 10 is AB for cost reduction and weight reduction.
It is an injection molded product made of S resin, PP resin, or the like. It has a disk-shaped flange 11, and a head 12 projects in a hat shape from the center of the flange 11. The head 12 is provided with a slit 13 so that it can be easily deformed into a desired shape when it is later assembled as a product. The lead wire 30 is connected to the slit 13 by a suitable joining means such as ultrasonic welding or high frequency welding as described later. Slit 13
The shape of is shown as a concave (+) shape as in the embodiment of the figure, but it may be a concave of (−) shape.

Further, the entire peripheral surface of the electrode element 10 is coated with a conductive film. For this conductive film, a technique such as plating or coating is appropriately selected. In order to achieve goals such as high performance, ease of use, and adhesion, a mixed powder coating of silver (Ag) and silver chloride (AgCl ₂ ) is preferable. Further, as shown in FIG. 3, it is also practically effective to increase the reaction area by carving the mesh 14 on the bottom surface of the flange 11.

Next, in the assembly sectional view of FIG. 1, the electrode element 10 is insulated by being covered and housed by the electrode case (protective case) 20 having a hemispherical shell. Like the electrode element 10, the electrode case 20 is also an injection molded product made of ABS resin, PP resin, or the like. An annular or local convex portion 21 is projectingly provided at a predetermined position on the inner peripheral surface of the electrode case 20, and the flange 11 of the electrode element 10 is locked inside the convex portion 21. Since both the electrode element 10 and the electrode case 20 have resin elasticity, the flange 11 is pushed into the convex portion 21 on the electrode case 20 side for elastic fitting during assembly. Further, a through hole 22 through which the lead wire 30 penetrates is provided in the spherical portion of the electrode case 20.

Here, the core wire 31 of the lead wire 30 is C having a diameter of about 0.08 mm.
It is a u (copper) wire, and its end is welded to the slit 13 of the head 12 of the electrode element 10 by ultrasonic bonding or the like. It is desirable to protect the welded joint 32 of the lead wire 30 with a strong adhesive. When connecting the lead wire 30, the core wire 31 is inserted into the inside of the through hole 22 of the electrode case 20, and the inserted tip portion is used as the slit 1 of the head 12.
It is rolled up in 3 and ultrasonically welded.

The electrode element 10 to which the lead wire 30 is connected is the flange 1
1 is accommodated by elastically fitting the inside of the convex portion 21 of the electrode case 20. At this time, the head 1 of the electrode element 10
2 is deformed as shown in FIG. This deformation is slit 1
Effectively subsidized by 3. By appropriately setting the fitting relationship between the outer peripheral dimension of the flange 11 and the convex portion 21, the fitting clearance can be minimized, and the conductive paste 15 (see FIG. 3) can be used in practice in the flange 11 of the electrode element 10. Even if it is applied to the lower surface, it does not penetrate to the joint portion 32 of the lead wire 30 inside the electrode case 20, and noise such as that found in a normal silver chloride and / or silver-silver chloride powder compact electrode is generated. Don't worry.

The electrode case 20 has a structure that replaces the conventional resin molding provided on the outside of the electrode element as a measure for protecting the electrode, and can significantly reduce the work cost and the like as compared with the molding method. Structurally very simple.

In order to more reliably prevent the influence of the conductive paste on the joint portion 32 of the lead wire 30, a plastic protective film is formed on the joint portion 32 or between the electrode element 10 and the inside of the electrode case 20. The resulting voids 40 may be filled with a suitable adhesive such as epoxy or silicone. In the latter case, it is not necessary to provide the convex portion 21 for locking the flange 11 of the electrode element 10 on the inner surface of the electrode case 20.

The electroencephalogram measurement electrode of the present invention is not limited to use in electroencephalogram detection because of its performance, and can be applied to electrocardiogram, electromyogram, and impedance plethysmography.

Effects of the Invention As described above, the brain wave measuring electrode according to the present invention is
The complexity of using the silver electrode can be eliminated, and problems with the characteristics of the mixed electrode of silver chloride and silver can be eliminated, and in particular the problems such as the soaring cost seen in the latter mixed electrode can be eliminated, resulting in higher performance. In addition, it has great practical effects such as cost reduction and disposal.

[Brief description of drawings]

1 to 3 show an embodiment of an electrode for measuring an electroencephalogram according to the present invention. FIG. 1 is an assembled sectional view, FIGS. 2 and 3 are plan views of an electrode element and sectional views taken along line AA. Is. 10 ... Electrode element, 11 ... Flange, 12 ... Head,
13 ... Slit, 20 ... Electrode case, 21 ... Convex portion, 22 ... Lead wire through hole, 30 ... Lead wire, 3
1 ... core wire, 32 ... welded joint.

Claims (3)

[Scope of utility model registration request] 1. A resin electrode element comprising a head having a flange and a slit and having a conductive coating formed on the surface thereof, an insulating protective case for covering the electrode element from the head side and housing the electrode element, and an electrode. An electrode for measuring an electroencephalogram, comprising: a lead wire connected to the head of the element and led out from the protective case, wherein the electrode element is elastically fitted to the protective case via a flange. 2. The electrode for measuring an electroencephalogram according to claim 1, wherein the conductive film is formed by coating with metal or metal powder. 3. The electrode for measuring an electroencephalogram according to claim 1, wherein the conductive film is silver, silver chloride, or a mixture of silver and silver chloride.