Non-inductive wireless electroencephalogram cap using dry electrode

Abstract

The utility model discloses a non-inductive wireless electroencephalogram cap using a dry electrode, and belongs to the technical field of medical instruments. The electroencephalogram cap comprises a cap-shaped silica gel substrate, the inner surface of the silica gel substrate is provided with a strip-shaped or sheet-shaped printing substrate in a printing electrode and printing wire area, and the printing electrode and the printing wire are coated on the printing substrate through spraying, brush coating, blade coating or printing and are packaged through a sealing layer and a wire packaging substrate respectively. According to the electroencephalogram cap, the main body structure of the electroencephalogram cap is made of a silica gel material, the electrodes and the wires are made by adopting a printing electronic process, the printed wires are connected with an external measuring wire and an instrument through a flexible flat cable after being gathered, and an area covered by the electroencephalogram cap is not provided with any high-hardness structure and part, so that the electroencephalogram cap is very comfortable to wear. The electrode is formed by printing stretchable conductive ink, has low impedance and high flexibility and is tightly attached to the scalp in the long-time wearing process, and the obtained electroencephalogram signal is excellent and stable.

Description

Technical Field

[0001] The utility model relates to a non-inductive wireless electroencephalogram cap using dry electrodes, belongs to the technical field of medical equipment, and relates to the design and construction of an electroencephalogram cap. Background Art

[0002] Electroencephalography (EEG) signals can be used for the diagnosis and treatment of diseases such as epilepsy and brain trauma, and can also be applied to human-computer interaction, game control, and psychological state monitoring. In order to accurately collect and analyze EEG data, reliable EEG data acquisition electrodes are required. EEG acquisition mainly includes portable EEG caps and directly implanted electrodes. Among them, EEG caps have the advantages of high safety, low cost, and wide range of use. There are mainly two types of electrodes in EEG caps: dry electrodes and wet electrodes. Wet electrodes have low impedance and stable signals, but they are less comfortable to wear and require cumbersome scalp treatment before and after the test, making them unsuitable for long-term monitoring. Dry electrodes are often made of conductive rubber, metal, or other conductive materials. The signal quality may be affected by insufficient contact between the dry electrodes and the scalp. The signal-to-noise ratio is not as good as that of wet electrodes, and it is more difficult to record low-frequency signals. When worn for a long time, symptoms such as scalp sensitivity and redness may occur. Summary of the invention

[0003] The utility model proposes a new type of EEG cap based on a new type of dry electrode that is wear-free and has stable signals. The main structure of the EEG cap is constructed with silicone material, and the electrodes and wires are made of printed electronic technology. The printed wires are aggregated and connected to external measurement wires and instruments through soft flat cables. The area covered by the EEG cap does not have any high-hardness structures and components, and is very comfortable to wear. The electrodes are printed with stretchable conductive ink, which has low impedance and high flexibility. During long-term wearing, they fit tightly to the scalp, and the resulting EEG signals are excellent and stable.

[0004] The technical solution of the utility model is as follows: a non-conductive wireless EEG cap using dry electrodes comprises a cap-shaped silicone base, a strip-shaped or sheet-shaped printed base is arranged on the inner surface of the silicone base in the printed electrode and printed wire area, the printed electrodes and printed wires are coated on the printed base by spraying, brushing, scraping or printing, and are respectively packaged by a sealing layer and a wire packaging base; 2-4 wiring holes are arranged on the silicone base.

[0005] The sealing layer is made of conductive paste, EEG paste or EEG coupling agent, the wire packaging substrate is made of three-proof glue, Ecoflex platinum-cured silicone, polydimethylsiloxane or potting soft glue, and the printing substrate is made of elastic ultra-thin material with a thickness of 0.03-0.1 mm and an elongation at break of 100-200%;

[0006] The printed electrodes are circular with a diameter of 8-12 mm or square with a side length of 8~12 mm, and the number is an even number not less than 8 and not more than 64. Each printed electrode is connected to a printed wire, the width of the printed wire is 0.5~3 mm, the thickness of the printed electrode and the printed wire is 10~30μm, the square resistance is less than 100Ω / sq, and the resistance change does not exceed 100% when stretched by 10~30%.

[0007] Furthermore, the printing substrate is made of thermoplastic polyester elastomer, polyethylene, thermoplastic polyurethane, nitrile rubber or polyvinylidene chloride.

[0008] Furthermore, the silicone base comprises a cap body covering the entire brain area and a strap buckled on the chin, and the thickness of the silicone base is 1-2 mm and the hardness is Shore A 30-40.

[0009] Furthermore, the printed electrodes and printed conductors are coated on the printed substrate by screen printing or inkjet printing using stretchable conductive ink.

[0010] Specifically, the silicone base includes a cap body covering the entire brain area and a strap buckled on the lower jaw (an integrated molding structure may be used), which is the main structure of the EEG cap, accounting for more than 99% of the weight of the entire EEG cap, with a thickness of 1-2mm and a hardness of 30-40 Shore A. Its main function is to ensure that the EEG cap fits tightly to the brain, presses the printed electrodes against the scalp, ensures good contact between the electrodes, thereby reducing impedance and stabilizing the collected EEG signals. The silicone base has 2-4 holes with a diameter of 2cm on the top of the head to ensure that the printed wire wiring passes from the scalp to the outside of the EEG cap, and connects to external soft wiring and measuring instruments.

[0011] The printing substrate is made of elastic ultra-thin material, specifically thermoplastic polyester elastomer (TPEE), polyethylene (PE), thermoplastic polyurethane (TPU), nitrile rubber (VBR) or polyvinylidene chloride (PVDC), with a thickness of 0.03-0.1mm and an elongation at break of 100-200%. No cracks, breaks or other destructive behaviors will occur when stretched by 10-30%.

[0012] Specifically, the printed substrate only covers the area with electrodes and wires in the brain area, and has good adhesion to conductive ink (ASTM 5B grade), which is convenient for printing and subsequent production and improves the wearing comfort of the testers. The printed substrate is distributed in strips or sheets, and the electrodes are printed when the printed substrate is spread into a plane. After printing, it can be bonded to the silicone substrate with special silicone glue to form a smooth curved surface without wrinkles.

[0013] Printed electrodes and printed conductors are made of stretchable conductive inks, which are sprayed / brushed or printed on the printed substrate by brushing, scraping, screen printing or inkjet printing. The stretchable conductive inks are made of existing materials, and the conductive fillers are a mixture of one or more fillers in silver powder, graphene, carbon nanotubes, carbon black, PEDOT / PSS, and the connecting material is a resin or a mixture of multiple resins in polyurethane, acrylic resin, and silicone resin that have greater elasticity after curing into a film. After curing into a film, the ink film thickness is 10-30μm, the square resistance is less than 100Ω / sq, and the resistance change does not exceed 100% when stretched by 10-30%. The printed electrodes are round or square, with a diameter or side length of 8-12mm, and the number is any even number greater than or equal to 8 and less than or equal to 64. Each electrode is connected to a wire, and the width of the wire is 0.5-3mm. The conductive ink used for the printed wire is the same as that for the printed electrode, and its printing process, thickness, square resistance and stretch rate requirements are the same as those for the printed electrode. According to the electrode arrangement, the printed conductors are grouped and aggregated in multiples of 4, led out in the top area of ​​the head in the form of a cable interface, and then connected to external flexible cables and measuring instruments.

[0014] A very small amount of EEG paste (less than 5μm thick) is applied between the printed electrode and the scalp to seal and couple, i.e., the sealing layer, which is conducive to the close bonding between the electrode and the scalp. To prevent signal interference, the printed conductor area should be coated with three-proof glue, ecoflex, PDMS or potting soft glue for packaging (dry coating thickness less than 20μm) to prevent contact with the scalp and the influence of moisture, grease, etc. on the resistance.

[0015] Beneficial effects of the utility model:

[0016] (1) The EEG caps are all made of elastic soft materials, which can be worn without feeling and are suitable for use at night or for long-term monitoring.

[0017] (2) The electrodes are printed with stretchable conductive ink, which has low impedance and high flexibility, fits tightly to the scalp, and the resulting EEG signals are excellent and stable.

[0018] (3) The printed base layer is prepared in strips and slices to facilitate plane printing and subsequent assembly, avoiding the formation of a multi-layer heavy structure. This can further reduce the thickness and softness of the entire EEG cap and improve the comfort of the tester for long-term wearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the structure of a non-conductive wireless EEG cap using dry electrodes.

[0020] Figure 2 It is a schematic diagram of the distribution of the printed substrate.

[0021] Figure 3A partial cross-sectional view of a non-contact wireless EEG cap using dry electrodes when worn. DETAILED DESCRIPTION

[0022] In order to make the advantages of the embodiments of the present invention more clear, the advantages of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention.

[0023] Figure 1 The schematic diagram of the structure of a non-contact wireless EEG cap using dry electrodes is shown. In the figure, the non-contact wireless EEG cap using dry electrodes includes a cap-shaped silicone base, which includes a cap body covering the entire brain area and a strap buckled on the lower jaw, with a thickness of 1 mm and a hardness of Shore A 30. The inner surface of the silicone base is bonded with a strip-shaped and sheet-shaped printed base by glue. The printed electrodes and printed wires are coated on the printed base by inkjet printing using stretchable conductive ink, and are respectively encapsulated by a sealing layer and a wire encapsulation base (such as Figure 3 As shown in the figure), two wiring holes are set on the silicone base.

[0024] The sealing layer uses conductive paste, the wire encapsulation base uses three-proof glue, and the printed base uses thermoplastic polyurethane material with a thickness of 0.05mm and a breaking elongation of 150%. The printed electrodes are 10 mm in diameter and the number is 64. Each printed electrode is connected to a printed wire. The width of the printed wire is 1.5 mm. The thickness of the printed electrode and the printed wire is 20μm, the square resistance is less than 100Ω / sq, and the resistance change does not exceed 100% when stretched by 30%.

[0025] Printing substrates are divided according to the principle of convenience of pasting and convenience of printing electrodes. Figure 2 As shown in the figure, the printed substrate is divided according to the longitude and latitude of the brain area where it is located. The middle area is divided into three strips along the longitude direction. The left strip prints 5 electrodes F1, FC1, C1, CP1, and P1 and their wires; the middle strip prints 8 electrodes FPZ, FZ, FCZ, CZ, CPZ, PZ, POZ, and OZ, a ground electrode (GND), and a reference electrode (REF) and their wires; the right strip prints 5 electrodes F2, FC2, C2, CP2, and P2 and their wires; the two side areas are divided according to the latitude direction, with 5 strips on each side. The division positions and printed electrodes are shown in the figure. Figure 2 There are four triangular sheet substrates, which are used to divide the positions and print the electrodes. Figure 2 shown.

Claims

1. A non-conductive wireless EEG cap using dry electrodes, comprising a cap-shaped silicone base, characterized in that: The inner surface of the silicone base is provided with a strip or sheet-shaped printing base in the printed electrode and printed wire area, and the printed electrode and printed wire are coated on the printing base by spraying, brushing, scraping or printing, and are respectively encapsulated by a sealing layer and a wire encapsulation base; 2-4 wiring holes are arranged on the silicone base; The sealing layer is made of conductive paste, EEG paste or EEG coupling agent, the wire packaging substrate is made of three-proof glue, Ecoflex platinum-cured silicone, polydimethylsiloxane or potting soft glue, and the printing substrate is made of elastic ultra-thin material with a thickness of 0.03-0.1 mm and an elongation at break of 100-200%; The printed electrodes are circular with a diameter of 8-12 mm or square with a side length of 8~12 mm, and the number is an even number not less than 8 and not more than 64. Each printed electrode is connected to a printed wire, the width of the printed wire is 0.5~3 mm, the thickness of the printed electrode and the printed wire is 10~30μm, the square resistance is less than 100Ω / sq, and the resistance change does not exceed 100% when stretched by 10~30%.

2. The non-conductive wireless EEG cap using dry electrodes according to claim 1, characterized in that: The printing substrate is made of thermoplastic polyester elastomer, polyethylene, thermoplastic polyurethane, nitrile rubber or polyvinylidene chloride.

3. The non-conductive wireless EEG cap using dry electrodes according to claim 1, characterized in that: The silicone base comprises a cap body covering the entire brain area and a strap buckled on the chin. The thickness of the silicone base is 1-2 mm and the hardness is Shore A 30-40.

4. The non-conductive wireless EEG cap using dry electrodes according to claim 1, characterized in that: Printed electrodes and printed conductors are coated on a printed substrate by screen printing or inkjet printing using stretchable conductive ink.

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