WO2017175957A1

WO2017175957A1 - Multichannel microelectrode for eeg measurement

Info

Publication number: WO2017175957A1
Application number: PCT/KR2017/000641
Authority: WO
Inventors: 성호근; 김신근; 이희관; 최지현; 김수학
Original assignee: (재)한국나노기술원
Priority date: 2016-04-05
Filing date: 2017-01-19
Publication date: 2017-10-12
Also published as: KR101749511B1

Abstract

Provided is a multichannel microelectrode for EEG measurement, the microelectrode comprising: a flexible thin-film type substrate; a conductive material, a ground electrode, a recording electrode, and an interconnection pad formed on the flexible thin-film type substrate; a first connector or a first wireless communication module; and a first PCB substrate. The ground electrode and the recording electrode are connected to the interconnection pad through the conductive material, and the interconnection pad is fixed to one face of the first PCB substrate and is connected to the first connector or the first wireless communication module. According to the present invention, a microelectrode made of a flexible thin-film type substrate having a micrometer-level thickness can be connected to a connector without a danger of detachment therefrom, and enables a stable EEG measurement regardless of the movements of a subject.

Description

Multichannel Microelectrode for EEG Measurement

The present invention relates to a multichannel microelectrode for measuring electroencephalography (EEG). More specifically, the present invention relates to a multi-channel microelectrode for measuring EEG connected to a connector using a PCB substrate.

Electroencephalography (EEG) is a representative biosignal that captures brain activity spatio-temporal and has been widely used in clinical and brain function research. Electroencephalogram measurement involves attaching electrodes to the user's scalp to measure the current generated by brain activity.

In order to measure EEG with an EEG electrode, an operation of implanting an electrode by puncturing the skull was involved. However, Patent Document 1 uses a polyimide-based microelectrode to induce free movement of an experimental animal from as many sites as possible. At the same time, it shows how to record EEG.

However, the microelectrode according to Patent Document 1 is considerably thin at the micrometer level, so that it is not easy to attach the electrode to the connector for connecting to a separate signal acquisition device, and the conductive paste, anisotropic conductive film, solder material (eg, solder paste, Solder preform, solder flux, etc.) or eutectic metal (eg, AuSn, NiSn, AgSn, AuIn, AgIn, etc.), even if the connector is connected to the electrode, there is a problem that the connector is easily detached due to low adhesion to the polyimide substrate.

Accordingly, the EEG can be stably measured without fear of detachment of the thin electrode and the connector when the object is moved or the connector is separated by improving the adhesion between the thin electrode and the connector applied to the animal. It is required to design the structure of the microelectrode so that it is possible. In addition, a method of introducing a wireless communication module capable of removing a wired signal line that obstructs a subject's movement is required.

One aspect of the present invention provides a multi-channel microelectrode for measuring EEG in the form of a thin film that can stably measure the EEG without fear of detachment of the thin film-type microelectrode and the connector when the subject moves or separates the coupled connector. I would like to present. The present invention also proposes a microelectrode incorporating a wireless communication module that can remove a wired signal line that obstructs the movement of a subject.

However, the problem to be solved by the present invention is not limited to the above-mentioned problem, another task that is not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, an aspect of the present invention, a thin film flexible substrate; A conductive material, a ground electrode, a recording electrode, and an interconnection pad formed on the thin film flexible substrate; A first connector or a first wireless communication module; And a first PCB substrate, wherein the ground electrode and the recording electrode are connected to the interconnection pad through the conductive material, and the interconnection pad is fixed to one surface of the first PCB substrate such that the first connector or Provided is a multi-channel microelectrode for measuring EEG, which is connected to a first wireless communication module.

Another aspect of the present invention provides a multi-channel microelectrode set for EEG measurement, in which a plurality of units of the microelectrode are connected to each microelectrode unit.

According to the present invention, a micro electrode made of a thin flexible flexible substrate having a micrometer-level thickness can be connected to a connector without fear of detachment, so that the EEG can be stably measured without being concerned with the movement of the subject, and the measurement is not performed. It is easy to separate the microelectrode from the subject to provide ease of use.

1 is a configuration diagram in which a microelectrode and a connector are connected on a lower substrate according to an embodiment of the present invention.

2 is a diagram illustrating an operation of raising a microelectrode on a lower substrate and attaching a connector thereon according to an embodiment of the present invention.

3 is a configuration diagram in which a microelectrode is inserted between two PCB substrates and a connector is connected to an upper portion according to an embodiment of the present invention.

FIG. 4 is a working view of placing a microelectrode between two PCB substrates and attaching a connector thereon according to an embodiment of the present invention.

5 is a conceptual diagram illustrating coupling of a lead frame with a connector on a microelectrode according to an embodiment of the present invention.

6 is a configuration diagram in which a microelectrode and a connector are connected on one PCB substrate according to an embodiment of the present invention.

FIG. 7 is a working view of placing a microelectrode on one PCB substrate and attaching a connector to the upper portion according to an embodiment of the present invention.

FIG. 8 is a diagram in which a microelectrode is formed as a set of protective substrates on both surfaces of a flexible substrate on which a ground electrode and a recording electrode are positioned in the microelectrode according to an embodiment of the present invention.

FIG. 9 is a diagram illustrating a flexible substrate on which a ground electrode and a recording electrode are positioned in a microelectrode according to an embodiment of the present invention, adhered to a protective substrate, and the microelectrodes are configured as a set.

10 is a product photograph of the microelectrode (a, b, c, d, e) with a connector manufactured according to an embodiment of the present invention, (c) is provided with a protective substrate on both sides of the electrode portion (D) is packaged in a form in which an electrode portion is adhered to one surface of the protective substrate.

FIG. 11 is a photograph of a microelectrode prepared according to an embodiment of the present invention on a skull of a mouse and measuring EEG. FIG.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present disclosure. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted for simplicity of explanation, and like reference numerals designate like parts throughout the specification.

Throughout this specification, when a portion is "connected" to another portion, this includes not only "directly connected" but also "electrically connected" with another element in between. do.

Throughout this specification, when a member is located "on" another member, this includes not only when one member is in contact with another member but also when another member exists between the two members.

Throughout this specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding the other components unless specifically stated otherwise.

In addition, terms including ordinal numbers such as first and second used herein may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

The present invention solves the problem of weak adhesion between the electrode and the thin film flexible substrate having the electrode, which performs the function of connecting the electrode to the signal acquisition device in measuring the EEG of the subject through the electrode formed on the thin film flexible substrate. In addition, a new type of microelectrode structure for transmitting a biosignal using a wireless communication module is proposed.

The multi-channel microelectrode for measuring EEG proposed in the present invention includes a thin film flexible substrate; A conductive material, a ground electrode, a recording electrode, and an interconnection pad formed on the thin film flexible substrate; A first connector or a first wireless communication module; And a first PCB substrate, wherein the ground electrode and the recording electrode are connected to the interconnection pad through the conductive material, and the interconnection pad is fixed to one surface of the first PCB substrate such that the first connector or It may have a structure connected to the first wireless communication module.

The microelectrode of the present invention is for measuring brain waves of animals including humans, and electrodes are formed on a thin film flexible substrate. The flexible substrate is preferably a biocompatible material, and typically, polymethylmethacrylate (PMMA), polydimethylsiloxane (PDMS), polystyrene (PS), polycarbonate (PC), cyclic olefin copolymer (COC), polyimide (PI), and polyethylene terephthalate (PET). ), But may be made of one or two or more materials selected from the group consisting of polyethylene-naphthalate (PEN), but is not limited thereto. The flexible substrate is more elastic than rigid silicon and reduces tissue damage by reducing the incompatibility in the mechanical properties between the electrode and the tissue. In addition, the thickness of the flexible substrate may be 1 ~ 1000㎛, but is not limited thereto.

The conductive material 112, the ground electrode 113, the recording electrode 114, and the interconnection pad 115 are formed on the flexible substrate 111. The conductive material may be used as a material for forming a connection line for transmitting an EEG signal from an electrode, a contact point of the electrode, and an interconnection pad. The conductive material may include Pt, Ag, AgCl, Au, AuCl, Ir and the like. These conductive materials are used to form connecting lines, contact points, and interconnect pads on the flexible substrate by deposition methods such as sputtering, e-beam evaporation, and thermal evaporation.

For example, the conductive material is patterned on the flexible substrate, and then the biocompatible material material is coated and adhered onto the patterned conductive material. Then, after forming the pattern through the photolithography process, the contact point and the interconnect pad of the electrode are exposed through the selective reactive ion etching (RIE) and the chemical etching process. The above steps are repeated in order to increase the contact point and interconnect pad area of the exposed electrode or to increase the number of contact points and interconnect pads of the electrode.

The thickness of the thin film flexible substrate 111 including the conductive material 112, the ground electrode 113, the recording electrode 114, and the interconnection pad 115 may be 1 to 1000 μm. However, the present invention is not limited thereto. The ground electrode 113 and the recording electrode 114 are connected to the interconnection pad 115 through the conductive material 112.

One ground electrode may be formed on each side of the center line as a reference electrode, but is not limited thereto.

The working electrode may include a contact point and a connection line, and the area of the contact point may be 0.1 to 100 mm 2, but is not limited thereto. The recording electrodes may be plural in number, and may be arranged in a line along the plurality of flexible substrates, which may extend from the center line to both sides, respectively.

In determining the location of the recording electrodes, the electrodes for human EEG can be positioned according to the 10-20 or 10-10 system usually recommended by the American EEG Society. For example, at standard measurement positions such as Fp1, Fp2, F3, Fz, F4, F7, F8, T3, C3, Cz, C4, T4, T5, P3, Pz, P4, T6, O1, O2 on the scalp EEG information can be measured, but is not limited thereto.

As described above, the microelectrode (hereinafter, simply referred to as “thin-film microelectrode”) made of a thin film flexible substrate including the conductive material, the ground electrode, the recording electrode, and the interconnection pad separates the EEG signal received from the electrode. In order to connect to a signal acquisition device, a wired communication module or a wireless communication module is required.

A representative example of the wired communication module is a connector.

In addition, examples of the wireless communication module may include an internet module, a short range communication module, and other communication means.

The internet module refers to a module for internet access, and may be connected to the thin film type microelectrode, embedded in the signal acquisition device, or external. Internet technologies may include Wireless LAN (Wi-Fi), Wireless Broadband (Wibro), World Interoperability for Microwave Access (Wimax), High Speed Downlink Packet Access (HSDPA), and the like.

The short range communication module refers to a module for short range communication. As a short range communication technology, Bluetooth, Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra Wideband (UWB), ZigBee, etc. may be used.

The wired communication module (for example, a connector) or the wireless communication module may be integrally formed including a power supply unit.

The above-described wired communication module (for example, a connector) may be commonly applied to the first connector and the second connector, which will be described later. The above-described wireless communication module may be described in detail as follows. It may be applied in common with respect to the second wireless communication module.

The first method of electrically connecting the ground electrode and the recording electrode to the signal acquisition device through the connector is to fix the thin film type microelectrode on the lower substrate serving as a support and to connect the interconnect pad and the connector of the thin film type microelectrode. At this time, a conductive paste or an anisotropic conductive film (ACF), a solder material (eg, solder paste, solder preform, solder flux, etc.) or a eutectic metal (eg, AuSn, NiSn, AgSn, AuIn, AgIn Etc.). As shown in FIG. 1, a photograph of the microelectrode combined with the connector manufactured as described above is shown in FIG. 10A, which is shown in FIG. 2. It is fabricated by raising the interconnection pad 115 of the electrode 110 and attaching the connector 210 thereon. In this case, there is a problem in that the adhesive force with the connector is weak due to the characteristics of the flexible substrate in the form of a film. Although the adhesive force is weak even in the static state, a situation in which the subject moves during the EEG measurement or when the connector is detached from the subject may cause a problem that the connector is separated from the thin film microelectrode.

In the second method, a circuit board (or PCB board) patterned with an electrical connection line is used instead of a general board to solve the above problem. An interconnection pad of the thin film microelectrode 120 may be positioned between two

PCB substrates

410 and 420, and a connector 220 or a wireless communication module may be connected to an upper portion thereof. The schematic diagram of the manufactured microelectrode is shown in FIG. 3, and a photograph thereof can be confirmed through FIG. 10 (b). As shown in FIG. 4, the microelectrode interconnection pad is positioned between the upper and lower PCB substrates, and the connector or the wireless communication module is attached to the upper PCB substrate. In this case, the connector or the wireless communication module may be attached to one of the upper PCB board and the lower PCB board or attached to both the upper PCB board and the lower PCB board.

That is, the interconnection pad is fixed to one surface of the first PCB substrate 410 and connected with the first connector 220 (or the first wireless communication module). The first connector 220 (or the first wireless communication module) is fixed to one surface of the second PCB substrate 420, and the other surface of the second PCB substrate 420 is the first PCB substrate 410 and the Contact the interconnect pads. The first PCB 410 substrate and the second PCB substrate 420 may be printed on both surfaces of the circuit board. In addition, a first connector 220 (or a first wireless communication module) is attached to one of the first PCB substrate 410 and the second PCB substrate 420, or the first connector is attached to the first PCB substrate 410. 220 (or a first wireless communication module) may be attached, and a second connector (or second wireless communication module) may be attached to the second PCB substrate 420. (Not shown in the second connector (or second wireless communication module))

In this case, two PCB boards are required, so the weight and volume can be rather large.

In a third method, a thinner and simpler microelectrode can be obtained. In the second method, if two PCB boards are used, weight and volume can be reduced by using one PCB board. An interconnection pad of the thin film microelectrode is placed on the PCB substrate, and the interconnection pad and the connector (or wireless communication module) of the thin film microelectrode are connected to each other. At this time, a connector (or a wireless communication module) allows the interconnection pad and the circuit board of the PCB board to be simultaneously connected. For example, a connector (or wireless communication module) can be configured to simultaneously contact the interconnect pad and the circuitry of the PCB substrate. A schematic diagram of the manufactured microelectrode is shown in FIG. 6, and a photograph thereof can be confirmed through FIG. 10 (d). This may be fabricated by raising the interconnect pad of the thin film microelectrode 130 on the PCB substrate 430 and attaching a connector 230 (or wireless communication module) thereon. Alternatively, an additional connector may be attached to the lower portion of the PCB board 430.

That is, the interconnection pad is fixed to one surface of the first PCB substrate 430 and connected with the first connector 230 (or the first wireless communication module). The first connector 230 (or the first wireless communication module) is in contact with the first PCB substrate 430 and the interconnection pad so as to be positioned on top of the first PCB substrate 430 and the interconnection pad. do. Alternatively, a second connector (or second wireless communication module) may be attached or fixed to the other surface of the first PCB board 430. (Not shown in the second connector (or second wireless communication module))

In this case, the thin film type microelectrode may be strongly attached to the connector, and the thin and simple structure may reduce the burden on the subject during EEG measurement.

The microelectrode manufactured by the above three methods may be used by combining the connector part with a lead frame 700 as shown in FIG. 5.

The thin film type microelectrode introduced in the above three methods includes an interconnection pad portion to which a connector (or a wireless communication module) is attached, and an electrode portion that is not attached to the connector (or a wireless communication module), that is, a ground electrode and a recording electrode. It can be divided into the flexible base material area which is located.

The exposed electrode portion of the flexible substrate 111 constituting the thin film type microelectrode, that is, the region where the ground electrode 113 and the recording electrode 114 are located, is provided with a protective substrate on one or both surfaces of the flexible substrate. It may be removable. The protective substrate may be a sheet or a substrate made of a material of plastics, metals, glass, or paper with pulp added thereto, but is not limited thereto.

Referring to FIG. 8,

protective substrates

510 and 520 are provided on the upper and lower surfaces of the exposed electrode, respectively. This prevents the electrode part having a thickness of micrometer level from being damaged and provides stability when storing and carrying the microelectrode. The protective substrate may be a transparent, translucent, or opaque material. When using a microelectrode, the protective substrate can be removed and the electrode can be used for EEG measurement. A cutting line 611 is provided between the interconnect pad portion and the electrode portion to facilitate removal of the protective substrate. The thin film type microelectrode provided with the protective substrate on the upper and lower surfaces of the electrode portion exposed through FIG. 10 (c) can be confirmed with a photograph.

The present invention also provides a multi-channel microelectrode set for measuring EEG, in which a plurality of microelectrode units are connected to each microelectrode unit to be separated.

The thin film type microelectrode provided with the connector and the protective substrate may be manufactured in a packaged form in which a plurality of thin film electrodes are connected to each other. In this case, each microelectrode may be provided with an additional cutting line 612 for each microelectrode unit so that the microelectrode may be detached from the set every time it is used.

Referring to FIG. 9 as another method of providing a protective substrate, the protective substrate 530 is provided only on one surface of the exposed electrode part. In this case, the electrode part is stuck on the protective base material 530, and when using it, the protective base material 530 can be easily detached and separated.

There is also a cutting line 621 between the interconnect pad portion and the electrode portion to facilitate removal of the protective substrate. In addition, an additional cutting line 622 is provided to separate the unit microelectrode from the packaged thin film microelectrode.

10 (e), the protective substrate is provided only on one surface of the exposed electrode, and the microelectrodes are packaged into a set.

Since the microelectrode according to the present invention includes a wireless communication module such as Bluetooth, the microelectrode can acquire a signal even in a wireless electronic device including a portable terminal without the need to receive an EEG signal by wire.

In addition, the multi-channel microelectrode for measuring EEG of the present invention includes a plurality of recording electrodes, and an impedance difference due to a difference in distance between these recording electrodes may occur, thereby causing an error in measurement. In order to solve this problem and apply a uniform impedance, a method of computer programming an error according to the distance difference between the recording electrodes and canceling it from the actual measured EEG signal information may be adopted.

The photograph of measuring the EEG of the mouse using the prepared microelectrode can be seen through FIG. After vertical dissection of the scalp of the mouse, EEG can be measured by directly placing the microelectrode of the present invention on the skull.

The microelectrode of the present invention is capable of measuring EEG continuously without fear of detachment of the connector even when the subject moves during EEG measurement. When the microelectrode is not measured, the microelectrode can be immediately removed, and it is easy to carry and store.

Claims

Thin film flexible substrate; A conductive material, a ground electrode, a recording electrode, and an interconnection pad formed on the thin film flexible substrate; A first connector or a first wireless communication module; And a first PCB substrate,

The ground electrode and the recording electrode are connected to the interconnection pad via the conductive material;

The interconnect pad is fixed to one surface of the first PCB substrate and connected with the first connector or the first wireless communication module.
The method of claim 1,

Wherein the first connector or first wireless communication module is in contact with the first PCB substrate and the interconnection pad and positioned on top of the first PCB substrate and the interconnection pad.
The method of claim 1,

The first connector or the first wireless communication module is fixed to one side of a second PCB substrate printed circuit on both sides, the other side of the second PCB substrate is in contact with the first PCB substrate and the interconnection pad. , Multi-channel microelectrode for EEG measurement.
The method of claim 1,

The first PCB substrate is a circuit printed on both sides, the second connector or the second wireless communication module is fixed to the other surface of the first PCB substrate, the multi-channel microelectrode for measuring EEG.
The method of claim 4, wherein

The first wireless communication module and the second wireless communication module is an internet module or a short-range communication module, EEG measurement multi-channel microelectrode.
The method of claim 4, wherein

The first connector, the first wireless communication module, the second connector, or the second wireless communication module is a multi-channel microelectrode for measuring EEG.
The method of claim 4, wherein

Wherein the first connector, the first wireless communication module, the second connector, or the second wireless communication module perform a function of connecting the ground electrode and the recording electrode to a signal acquisition device. Channel microelectrode.
The method of claim 1,

In the region in which the ground electrode and the recording electrode are positioned among the thin film flexible substrates, a protective substrate is provided on one or both surfaces of the flexible substrate, and the protective substrate is removable and detachable. .
The method of claim 1,

The thin film flexible substrate is polymethylmethacrylate (PMMA), polydimethylsiloxane (PDMS), polystyrene (PS), polycarbonate (PC), cyclic olefin copolymer (COC), polyimide (PI), polyethylene terephthalate (PET), polyethylene-naphthalate (PEN) A multichannel microelectrode for measuring EEG, comprising one or two or more materials selected from the group consisting of:
The method of claim 1,

The thickness of the thin film flexible substrate including the conductive material, the ground electrode, the recording electrode and the interconnection pad is 1 ~ 1000㎛, multi-channel microelectrode for EEG measurement.
The method of claim 1,

The recording electrode includes a contact point and a connecting line, the area of the contact point is 0.1 to 100mm2, EEG measurement multi-channel microelectrode.
The method of claim 1,

And a plurality of recording electrodes, arranged in a line along a plurality of the flexible substrates, each of which extends side by side from a center line to both sides.
A multi-channel microelectrode set for measuring EEG, wherein a plurality of units of the microelectrode according to claim 8 are connected to each other so that each microelectrode unit is separable.