Rubber coating mold, brain electrode implant, preparation method of brain electrode implant and brain-computer interface system

Abstract

The invention relates to the technical field of medical product processing and manufacturing, and discloses a rubber coating mold, a brain electrode implant, a preparation method of the brain electrode implant and a brain-computer interface system. Wherein the rubber coating mold comprises an upper mold and a lower mold, the upper mold is provided with an upper mold cavity groove, the lower mold is provided with a lower mold cavity groove, the upper mold is detachably connected to the lower mold, the upper mold cavity groove and the lower mold cavity groove define a forming cavity, and the forming cavity is used for coating the periphery of a brain electrode and a printed circuit board which are fixedly connected in a stacked mode to form a flexible protection body; the rubber coating mold is provided with a positioning groove used for embedding a main body part of the printed circuit board and further provided with a receding groove used for containing a contact area of the brain electrode, and the positioning groove, the forming cavity and the receding groove are sequentially arranged. And the rubber coating mold is used for positioning the non-rubber-coated product, so that the forming quality is improved. The contact area of the brain electrode is located in the receding groove, damage caused by complete pressing is avoided, excessive floating caused by complete receding is also prevented, and finally the brain electrode implant wrapped with the flexible protection body is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical product processing and manufacturing, and particularly relates to a coating mold, a brain electrode implant and a preparation method thereof, and a brain-computer interface system. BACKGROUND

[0002] The brain-computer interface is a frontier and transformative human-computer interaction technology combining life science and information science. It realizes the collaborative interaction of biological intelligence and machine intelligence by establishing an information channel between the brain and a machine. The mechanism of the brain-computer interface is unique. It bypasses peripheral nerves and muscles, directly builds a new communication and control channel between the brain and an external device, and realizes information transmission and control by capturing and converting brain signals.

[0003] In the existing brain-computer interface technology, the brain electrode implant is a key component for capturing brain signals. The brain electrode implant generally includes a brain electrode and a printed circuit board (PCB). The brain electrode is made of metal electrode points and wires with micron / nanometer thickness. Then, part of the metal electrode points and part of the PCB are connected through micro-assembly technology such as gold wire ball bonding, and then an electrical connection is formed between the PCB and an external device.

[0004] However, the existing typical preparation scheme of the brain electrode implant has obvious deficiencies. The connection area between the brain electrode and the printed circuit board in the brain electrode implant has poor mechanical reliability. The gold wire bonding points and the gold wire have low mechanical strength. They are easily broken due to physical action during surgical implantation, daily use or brain tissue micro-motion, resulting in signal channel failure and lack of effective support. Moreover, when implanted in the cerebrospinal fluid environment for a long time, the connection area is easily eroded by the body fluid, affecting the stability of the electrical signal. At the same time, there is a lack of corresponding preparation mold that can conveniently realize the connection area and stable, safe and reliable connection. The brain electrode implant cannot be conveniently processed.

[0005] Therefore, there is an urgent need for a coating mold, a brain electrode implant, a preparation method thereof and a brain-computer interface system to solve at least one of the above problems. SUMMARY

[0006] Based on the above, the purpose of the present application is to provide a coating mold, a brain electrode implant, a preparation method thereof and a brain-computer interface system. The brain electrode implant is positioned to improve the molding quality. The damage caused by "complete tight pressing" is avoided, and the excessive floating caused by "complete avoidance" is also prevented. Finally, the brain electrode implant coated with a flexible protective body is obtained.

[0007] To achieve the above purpose, the following technical solutions are adopted in the present application: A coating mold is used for preparing a brain electrode implant. The brain electrode implant includes a printed circuit board and a brain electrode. The overmolding mold includes an upper mold and a lower mold. The upper mold is provided with an upper mold cavity groove, and the lower mold is provided with a lower mold cavity groove. The upper mold is detachably connected to the lower mold, and the upper mold cavity groove and the lower mold cavity groove form a molding chamber. The overmolding mold is provided with a positioning groove for embedding the main body of the printed circuit board, and the overmolding mold is also provided with a clearance groove for accommodating the contact area of ​​the brain electrode. The positioning groove, the molding chamber and the clearance groove are arranged in sequence.

[0008] As a preferred technical solution for overmolding, the molding chamber includes a first receiving area for accommodating the connection area of ​​the brain electrode implant and a second receiving area for accommodating a portion of the wire area of ​​the brain electrode. The spacing of the first receiving area along the thickness direction of the brain electrode is greater than the spacing of the second receiving area along the thickness direction of the brain electrode.

[0009] As a preferred technical solution for overmolding, the inner walls of the first and second accommodating areas are transitioned by curved surfaces.

[0010] As a preferred technical solution for overmolding, the lower mold is provided with the positioning groove, which is located at the bottom end of the lower mold cavity, and the depth of the positioning groove is shallower than that of the lower mold cavity.

[0011] As a preferred technical solution for overmolding, the upper mold is provided with a first limiting groove, and the lower mold is provided with a second limiting groove, the first limiting groove and the second limiting groove forming the clearance groove.

[0012] As a preferred technical solution for overmolding, the spacing of the clearance grooves along the thickness direction of the brain electrode ranges from 3mm to 7mm.

[0013] As a preferred technical solution for overmolding mold, the overmolding mold is provided with an overflow cavity, which is located on both sides of the molding cavity. The lower mold is provided with a lower mold overflow groove, which is located around the lower mold cavity. The upper mold is provided with an upper mold overflow groove, which is located around the upper mold cavity. The lower mold overflow groove and the upper mold overflow groove precisely correspond to each other and together constitute the overflow cavity.

[0014] As a preferred technical solution for overmolding, one of the upper mold and the lower mold is provided with multiple positioning pins, and the other is provided with multiple positioning holes. The positioning pins and the positioning holes correspond one-to-one, and the positioning pins can pass through the positioning holes.

[0015] As a preferred technical solution for overmolding, the upper mold and the lower mold are detachably connected by a plurality of fastening screws.

[0016] As a preferred technical solution for overmolding, it also includes an ejector screw, wherein the upper mold is provided with a first threaded hole, and the ejector screw is threadedly connected to the first threaded hole and can push against the lower mold.

[0017] A brain electrode implant, wherein the brain electrode implant is prepared using the aforementioned overmolding mold; The brain electrode implant includes a flexible protective body, brain electrodes, and a printed circuit board. The brain electrodes are provided with solder joint areas, and the printed circuit board is provided with pad portions. The solder joint areas are electrically connected to the pad portions to form a connection area, and the flexible protective body at least covers the connection area.

[0018] A method for preparing a brain electrode implant, comprising the aforementioned overmolding mold, wherein the brain electrode implant is prepared using the following steps: Electrically connecting brain electrodes and printed circuit boards to prepare uncoated products; The upper and lower molds of the mold are coated with a flexible fluid; Place the uncoated product onto the lower mold; The upper and lower molds are joined together, and then heated, cooled, and demolded to obtain the brain electrode implant.

[0019] A brain-computer interface system includes an EEG amplifier, an EEG acquisition unit, a host computer, and the aforementioned brain electrode implants, all electrically connected to each other.

[0020] The beneficial effects of this application are as follows: This application provides an overmolding mold, a brain electrode implant, a method for preparing the same, and a brain-computer interface system. The overmolding mold is used to prepare the brain electrode implant, which includes a printed circuit board and brain electrodes. The overmolding mold includes an upper mold and a lower mold. The upper mold has an upper mold cavity, and the lower mold has a lower mold cavity. The upper mold is detachably connected to the lower mold, and the upper and lower mold cavities form a molding chamber. The overmolding mold also has a positioning groove for embedding the main body of the printed circuit board and a clearance groove for accommodating the contact area of ​​the brain electrodes. The positioning groove, molding chamber, and clearance groove are arranged sequentially.

[0021] Uncoated products are prepared by electrically connecting brain electrodes and printed circuit boards. The upper and lower mold cavities are coated with a flexible liquid or fluid. The uncoated product is placed on the lower mold, which is connected to the upper mold. The main body of the printed circuit board is embedded in a positioning groove. This positions the uncoated product and precisely confines the printed circuit board to a preset position, preventing movement during mold closing and glue injection, thus improving molding quality. The contact area of ​​the brain electrodes is located within a clearance groove. This ensures that the upper and lower molds do not directly press against the electrode contact array in the nanometer-thick contact area, fundamentally preventing contact area malfunction or damage due to pressure. Furthermore, confining the contact area within the clearance groove creates a safe floating space, avoiding damage from "complete compression" and excessive drift caused by "complete clearance," effectively preventing functional damage or scratches caused by collisions or friction. The connection area between the printed circuit board and the brain electrode is located in the molding chamber, where heating, cooling, and demolding are performed. At this time, the flexible protective body covers at least the connection area between the printed circuit board and the brain electrode, resulting in a brain electrode implant covered with a flexible protective body, thereby improving the product quality of the brain electrode implant. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this application and these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the overall structure of the overmolding mold provided in the specific embodiments of this application; Figure 2 This is a cross-sectional view of the overmolding mold provided in the specific embodiments of this application; Figure 3 yes Figure 2 A magnified view of a section at point A in the middle; Figure 4 This is a schematic diagram of the upper mold provided in a specific embodiment of this application; Figure 5 This is a schematic diagram of the lower mold structure provided in a specific embodiment of this application; Figure 6 This is a schematic diagram of the overall structure of the brain electrode implant provided in the specific embodiments of this application; Figure 7 This is a schematic diagram of the structure of the brain electrodes provided in the specific embodiments of this application; Figure 8 This is a schematic diagram of the structure of the printed circuit board provided in a specific embodiment of this application; Figure 9 This is a schematic diagram of the structure of the flexible protective body provided in a specific embodiment of this application; Figure 10 This is a flowchart of the method for preparing a brain electrode implant according to a specific embodiment of this application; Figure 11 This is a schematic diagram of the composition structure of the brain-computer interface system provided in a specific embodiment of this application.

[0024] The markings in the image are as follows: 1. Brain electrode implant; 11. Flexible protective body; 111. First part; 112. Second part; 113. Third part; 12. Brain electrode; 121. Solder joint area; 122. Wire area; 123. Contact area; 13. Printed circuit board; 131. Connector; 132. Main body; 133. Solder pad; 2. Overmolding mold; 21. Upper mold; 211. First threaded hole; 212. Positioning hole; 22. Lower mold; 221. Positioning groove; 222. Positioning pin; 223. Second threaded hole; 23. Clearance groove; 231. First limiting groove; 232. Second limiting groove; 24. Molding chamber; 241. Upper mold cavity groove; 242. Lower mold cavity groove; 243. First part; 244. Second part; 245. Third part; 251. Upper mold overflow groove; 252. Lower mold overflow groove; 26. Fastening screw; 3. EEG amplifier; 4. EEG acquisition device; 5. Host computer. Detailed Implementation

[0025] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present application, not the entire structure.

[0026] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0027] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0028] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0029] Combination Figures 1-3 As shown, this application provides a rubber-coating mold for preparing a brain electrode implant 1.

[0030] The brain electrode implant 1 includes a brain electrode 12 and a printed circuit board (PCB). The brain electrode 12 is provided with a solder joint area 121, and the printed circuit board 13 is provided with a pad portion 133. Further, the brain electrode implant 1 includes a flexible protective body 11. The solder joint area 121 is electrically connected to the pad portion 133 to form a connection area, and the flexible protective body 11 at least covers the connection area.

[0031] The overmolding mold 2 includes an upper mold 21 and a lower mold 22. The upper mold 21 is provided with an upper mold cavity 241, and the lower mold 22 is provided with a lower mold cavity 242. The upper mold 21 is detachably connected to the lower mold 22. The upper mold cavity 241 and the lower mold cavity 242 form a molding chamber 24. The molding chamber 24 is used to cover the periphery of the stacked and fixedly connected brain electrodes 12 and printed circuit board 13 to form a flexible protective body 11 with the aforementioned structure. The overmolding mold 2 is provided with a positioning groove 221 for embedding the main body 132 of the printed circuit board 13. The overmolding mold 2 is also provided with a clearance groove 23 for accommodating the contact area 123 of the brain electrodes 12. The positioning groove 221, the molding chamber 24 and the clearance groove 23 are arranged in sequence.

[0032] Specifically, during processing, the brain electrodes 12 and the printed circuit board 13 are electrically connected to prepare an uncoated product; the upper mold cavity 241 and the lower mold cavity 242 are coated with a flexible liquid or flexible fluid; the uncoated product is placed on the lower mold 22, and the upper mold 21 is connected to the lower mold 22. At this time, the main body 132 of the printed circuit board 13 is embedded in the positioning groove 221, which on the one hand positions the uncoated product; on the other hand, it precisely restricts the printed circuit board 13 to a preset position, preventing movement during mold closing and glue injection, thus improving molding quality. The contact area 123 of the brain electrodes 12 is located in the clearance groove 23, which on the one hand ensures that the upper mold 21 and the lower mold 22 do not directly press the electrode contact array in the nanometer-thick contact area 123, fundamentally preventing the contact area 123 from malfunctioning or breaking due to pressure. On the other hand, the contact area 123 is confined within the clearance groove 23, which forms a safe floating space. This avoids damage from "complete compression" and excessive drift caused by "complete clearance," thus effectively preventing functional damage or scratches caused by collisions or friction. The connection area between the printed circuit board 13 and the brain electrode 12 is located within the molding chamber 24 for heating, cooling, and demolding. At this time, the flexible protective body 11 at least covers the connection area between the printed circuit board 13 and the brain electrode 12, resulting in a brain electrode implant 1 covered with the flexible protective body 11, which improves the product quality of the brain electrode implant 1.

[0033] Optionally, combined Figures 4-5 As shown, the lower mold 22 is a rectangular metal plate, serving as the base of the overmolding mold 2, with a total height ranging from 13mm to 17mm, specifically 13mm, 14mm, 15mm, 16mm, or 17mm. The upper mold 21 is a rectangular metal plate corresponding to the lower mold 22, with a total height ranging from 13mm to 17mm, specifically 13mm, 14mm, 15mm, 16mm, or 17mm.

[0034] Optionally, combined Figure 1As shown, the molding chamber 24 includes a first receiving area for accommodating the connection area and a second receiving area for accommodating a portion of the lead wire area 122. The spacing of the first receiving area along the thickness direction of the brain electrode 12 is greater than the spacing of the second receiving area along the thickness direction of the brain electrode 12. By setting the molding chamber 24 with a non-uniform thickness, the distribution of the flexible liquid or flexible fluid (e.g., liquid silicone) is constrained, thereby directly molding a flexible protective body 11 with a specific thickness distribution, ensuring that the molded flexible protective body 11 possesses the expected zoned differentiated protection characteristics. It can be understood that the spacing of the first receiving area along the thickness direction of the brain electrode 12 directly determines the final thickness of the flexible protective body 11 in the connection area; the spacing of the second receiving area along the thickness direction of the brain electrode 12 directly determines the final thickness of the flexible protective body 11 in the lead wire area 122. In the final product, the total thickness of the control contact area 123 is minimized to reduce the implantation wound; while the total thickness of the connection area located outside the scalp is ensured to be above 1.5 mm to provide excellent structural strength and protection.

[0035] In some embodiments, the molding chamber 24 further includes a third receiving area for receiving a portion of the main body 132, wherein the spacing of the first receiving area along the thickness direction of the brain electrode 12 is slightly less than or equal to the spacing of the third receiving area along the thickness direction of the brain electrode 12, so that the main body 132 is easy to hold during use.

[0036] Further, both the upper model cavity 241 and the lower model cavity 242 include a first portion 243 corresponding to the second receiving area, a second portion 244 corresponding to the first receiving area, and a third portion 245 corresponding to the third receiving area. In some embodiments, the depth of the first portion 243 of the upper model cavity 241 and the lower model cavity 242 ranges from 0.15mm to 5mm, the length ranges from 6mm to 8mm, and the width ranges from 2mm to 4mm; the depth of the second portion 244 ranges from 0.5mm to 2mm, the length ranges from 6.5mm to 8.5mm, and the width ranges from 3.5mm to 5.5mm; and the depth of the third portion 245 ranges from 0.5mm to 2mm, the length ranges from 37.5mm to 47.5mm, and the width ranges from 2.5mm to 4.5mm.

[0037] In some embodiments, the depths of the upper mold cavity 241 and the lower mold cavity 242 equally divide the spacing of the molding chambers 24 along the thickness direction of the brain electrode 12. This facilitates reduced processing difficulty (e.g., simpler operation, easier demolding), optimizes the flow balance and venting efficiency of flexible liquids or fluids (e.g., liquid silicone), and reduces overflow; simultaneously improving product quality and appearance (e.g., concealed parting lines, uniform product surface, etc.). Of course, in other embodiments, the depths of the upper mold cavity 241 and the lower mold cavity 242 are set proportionally to the spacing of the molding chambers 24 along the thickness direction of the brain electrode 12, according to actual needs.

[0038] More preferably, combined with Figure 2 and Figure 3 As shown, the inner walls of the first and second receiving areas are transitioned by curved surfaces to ensure that the gradual thickness characteristics of the product can be accurately reproduced after mold closing. This avoids stress concentration and flow defects in the flexible protective body 11 at points of abrupt thickness changes, thus ensuring molding quality. The transition area between the first and second receiving areas is connected by a composite curved surface with radii of R10mm-R100mm, ensuring a smooth stress dispersion transition of the flexible protective body 11 between the two thickness regions. This effectively avoids the risk of internal stress concentration and cracking of the flexible protective body 11 that may occur due to abrupt thickness changes.

[0039] Furthermore, combined Figure 5 As shown, the lower mold 22 is provided with a positioning groove 221. The positioning groove 221 is located at the bottom end of the lower mold cavity groove 242. The depth of the positioning groove 221 is shallower than that of the lower mold cavity groove 242. The outline of the positioning groove 221 matches the shape of the main body 132 of the printed circuit board 13 in the uncoated product.

[0040] Furthermore, combined Figures 1-5 As shown, the upper mold 21 is provided with a first limiting groove 231, and the lower mold 22 is provided with a second limiting groove 232. The first limiting groove 231 and the second limiting groove 232 form an open space groove 23.

[0041] Specifically, the first limiting groove 231 and the second limiting groove 232 are precisely aligned and closed after the upper mold 21 and lower mold 22 of the overmolding mold 2 are closed, together forming a physically isolated, glue-free protective space for the contact area 123. This structure provides dual protection during the molding process: firstly, it physically isolates the electrode contacts of the contact area 123 from direct scouring and pressure by flexible liquids or fluids (such as liquid silicone), preventing displacement or mechanical damage; secondly, it avoids direct contact or pressing of the electrode area with contacts during mold closing. This design is crucial to ensuring the integrity and undamaged electrophysiological signal acquisition function of the brain electrode 12.

[0042] Furthermore, the spacing of the clearance grooves 23 along the thickness direction of the brain electrode 12 ranges from 3mm to 7mm, specifically 3mm, 4mm, 5mm, 6mm, or 7mm. With this size, damage to the contact area 123 of the brain electrode 12 due to "complete compression" can be avoided, and excessive drift caused by "complete clearance" can also be prevented.

[0043] For example, the depth of the first limiting groove 231 ranges from 1.5mm to 3.5mm, and the depth of the second limiting groove 232 also ranges from 1.5mm to 3.5mm. In some embodiments, the depths of the first limiting groove 231 and the second limiting groove 232 equally divide the spacing of the clearance grooves 23 along the thickness direction of the brain electrode 12. Of course, in other embodiments, according to actual needs, the depths of the first limiting groove 231 and the second limiting groove 232 are set proportionally to the spacing of the clearance grooves 23 along the thickness direction of the brain electrode 12.

[0044] In some examples, the first limiting groove 231 is located at the front end of the upper mold cavity groove 241, and the depth of the first limiting groove 231 is 2mm. When the main body 132 of the printed circuit board 13 is embedded in the positioning groove 221, the first limiting groove 231 provides a vertical clearance height of 2mm for the contact area 123. The second limiting groove 232 is located at the front end of the lower mold cavity groove 242, and its depth is 2mm. The position of the second limiting groove 232 corresponds precisely to the first limiting groove 231. After the lower mold 22 and the upper mold 21 are closed, the first limiting groove 231 and the second limiting groove 232 together constitute a precise limiting and clearance structure for the contact area 123, forming a clearance groove 23 with a total height of 4mm after mold closing.

[0045] It should be noted that when the brain electrode 12 is an invasive intracranial electrode of other structures, such as deep brain electrodes, stimulation electrodes, stereo electrodes and microneedle electrodes, the overmolding mold 2 can also be provided with a similar structure of clearance groove 23. The clearance groove 23 is also used to avoid damage to the contact area 123 of the brain electrode 12 of other structures by "complete compression", and also to prevent excessive floating caused by "complete clearance".

[0046] Optionally, the overmolding mold 2 is provided with overflow chambers, which are located on both sides of the molding chamber 24. By providing overflow chambers, it is possible to ensure that the molding chamber 24 is fully filled while effectively reducing air bubbles in the silicone, thereby improving process robustness, production efficiency, and product yield.

[0047] Furthermore, combined Figure 4 and Figure 5As shown, the lower mold 22 is provided with a lower mold overflow groove 252, which is located around the lower mold cavity 242. The lower mold overflow groove 252 is a continuous shallow groove with a depth of 0.5mm-0.8mm. The function of the lower mold overflow groove 252 is not only to accommodate excess silicone, but also to provide a point of leverage for burr removal of the cured product, making subsequent cleaning processes simple, efficient, and less likely to damage the product itself. The upper mold 21 is provided with an upper mold overflow groove 251, which is located around the upper mold cavity 241, and its position corresponds precisely to the lower mold overflow groove 252. When the mold is closed, the upper mold overflow groove 251 and the lower mold overflow groove 252 together form a complete overflow chamber, which also facilitates subsequent burr removal.

[0048] Optionally, one of the upper mold 21 and the lower mold 22 is provided with multiple positioning pins 222, and the other is provided with multiple positioning holes 212. The positioning pins 222 and the positioning holes 212 correspond one-to-one, and the positioning pins 222 can pass through the positioning holes 212.

[0049] For example, at least two positioning pins 222 are provided, symmetrically arranged on the lower mold 22. The positioning pins 222 are conical cylinders with a large end diameter of approximately 8 mm and a total height of 8 mm. Positioning holes 212 are provided on the upper mold 21. The position and number of positioning holes 212 correspond one-to-one with the positioning pins 222 of the lower mold 22. The hole diameter is approximately 8.5 mm. The positioning holes 212 and the positioning pins 222 form a clearance fit to ensure the guiding accuracy of mold closing.

[0050] Understandably, the positioning pin 222 of the lower mold 22 is precisely matched with the positioning hole 212 of the upper mold 21 to ensure that there is no horizontal misalignment when the mold is closed; the tapered design of the positioning pin 222 and the height difference with the positioning hole 212 facilitate the mold closing guidance and the separation of the upper mold 21 and the lower mold 22 when the mold is opened, effectively avoiding demolding difficulties caused by thermal expansion and contraction.

[0051] Optionally, the overmolding mold 2 also includes ejector screws. The upper mold 21 is provided with a first threaded hole 211, and the ejector screw is threaded into the first threaded hole 211 and can push against the lower mold 22. For example, two first threaded holes 211 are provided on both sides of the upper mold cavity 241, arranged diagonally. By rotating the two ejector screws counterclockwise or clockwise, the upper mold 21 and the lower mold 22 are brought closer or further apart.

[0052] Optionally, the upper mold 21 and the lower mold 22 are detachably connected by a plurality of fastening screws 26.

[0053] For example, the upper surface of the lower mold 22 is provided with six second threaded holes 223, which are evenly distributed on both sides of the lower mold cavity 242. The upper mold 21 is provided with six through holes, which correspond one-to-one with the six second threaded holes 223. The fastening screws 26 pass through the first through holes and are threaded to the second threaded holes 223 to mechanically lock the mold.

[0054] In some embodiments, combined with Figure 6 As shown, this application provides a brain electrode implant 1, which is prepared by the above-mentioned encapsulation mold 2. The brain electrode implant 1 includes a flexible protective body 11, a brain electrode 12 and a printed circuit board 13 (PCB). The brain electrode 12 is provided with a solder joint area 121, and the printed circuit board 13 is provided with a pad portion 133. The solder joint area 121 is electrically connected to the pad portion 133 and forms a connection area. The flexible protective body 11 covers at least the connection area.

[0055] The flexible protective body 11 provides mechanical support to the connection area. Firstly, the flexible protective body 11 provides structural protection to the connection area, providing mechanical support and stress buffering for the fixed bonding points, leads, and superimposed pads 133 in the connection area, preventing them from being damaged by external forces. This significantly improves its resistance to mechanical impact, bending, and fatigue, greatly enhancing the reliability of the brain electrode implant 1 during implantation and use. Secondly, the flexible protective body 11 isolates the connection area from the body fluid environment, forming a physical barrier to prevent electrolytic corrosion, ensuring long-term signal stability, and guaranteeing the electrical stability and biocompatibility of long-term implantation.

[0056] It should be noted that the brain electrode 12 included in the brain electrode implant 1 of this application may be a cortical electrode, such as a flexible cortical electrode; or an invasive intracranial electrode, such as a deep brain electrode, a stimulating electrode, a stereotactic electrode, or a microneedle electrode, as long as it can meet the performance requirements of direct contact with brain tissue, acquisition of high signal-to-noise ratio neural electrical signals, and provision of appropriate stimulation to the brain when needed.

[0057] Preferably, combined with Figure 7As shown, the brain electrode 12 is a miniature flexible cortical electrode fabricated using micro-electro-mechanical systems (MEMS) technology. It is used to directly contact the cerebral cortex and is responsible for acquiring high signal-to-noise ratio neural electrical signals and providing appropriate stimulation. Furthermore, the brain electrode 12 also includes a lead wire region 122 and a contact region 123. A solder joint region 121, a lead wire region 122, and a contact region 123 are arranged sequentially. The contact region 123 has multiple electrode contacts, the solder joint region 121 has multiple electrode solder joints, and the lead wire region 122 has multiple non-intersecting lead wires. The electrode contacts, electrode solder joints, and lead wires correspond one-to-one, with the two ends of the lead wires connected to the electrode contacts and electrode solder joints, respectively.

[0058] Furthermore, the contact area 123 includes multiple arrayed electrode contacts for direct contact with the cerebral cortex; the solder joint area 121 includes multiple arrayed electrode solder joints for stacking and fixing to the printed circuit board 13; the wire area 122 includes multiple non-intersecting wires to form a multi-channel connecting wire area 122, the wires being metal leads (i.e. conductive wires), and each wire is connected to an electrode contact and an electrode solder joint at both ends to form a conductive path.

[0059] In some embodiments, the overall thickness of the brain electrode 12 is 8μm-15μm, and the length of the brain electrode 12 ranges from 80mm to 140mm. The contact area 123, the wire area 122, and the solder joint area 121 are all approximately rectangular. The length of the contact area 123 ranges from 50mm to 70mm, and the width of the contact area 123 ranges from 10mm to 20mm; the length of the wire area 122 ranges from 10mm to 30mm, and the width of the wire area 122 ranges from 2mm to 6mm; the length of the solder joint area 121 ranges from 20mm to 40mm, and the width of the solder joint area 121 ranges from 4mm to 10mm.

[0060] Optionally, the printed circuit board 13 included in the brain electrode implant 1 in this application may be a rigid printed circuit board (RPCB), a flexible printed circuit board (FPC), a rigid-flex board, a high-density interconnect board, or a metal substrate.

[0061] Preferably, combined with Figure 8 As shown, the printed circuit board 13 is an FPC. The printed circuit board 13 also includes a main body 132 and a connector 131. The connector 131, the main body 132 and the pad 133 are arranged in sequence. The two ends of the main body 132 are electrically connected to the connector 131 and the pad 133 respectively. The connector 131 is used for electrical connection with external devices.

[0062] It is particularly emphasized that the printed circuit board 13 serves as a carrier, carrying and wiring the EEG signals collected by the brain electrodes 12 for aggregation and transmission. The connector 131 is used for electrical connection with external devices; the pad portion 133 includes an array of distributed pads for corresponding stacked and fixed connection with the solder joint area 121 of the brain electrodes 12. The connector 131 and the pad portion 133 are connected by the main body portion 132, which is easy to operate and hold.

[0063] Optionally, the overall thickness of the FPC is 0.3mm-0.4mm, and the length of the FPC ranges from 128mm to 165mm. The connector 131, body 132, and pad 133 of the FPC are all approximately rectangular. The connector 131 has a length and width ranging from 10mm to 20mm; the body 132 has a length and width ranging from 100mm to 120mm; and the pad 133 has a length and width ranging from 3mm to 8mm.

[0064] In some embodiments, the bonding pad portion 133 and the solder joint area 121 can be connected in a stacked and fixed manner using one or more of the following methods: gold wire ball bonding, laser welding, tin soldering, screen printing, or anisotropic conductive film bonding, to achieve electrical conduction of nerve signals from the acquisition point to the transmission line. Preferably, when screen printing is used, a conductive fluid paste can be used.

[0065] In some embodiments, preferably, the flexible protective body 11 covers a portion of the lead wire area 122. More preferably, the flexible protective body 11 covers a portion of the main body 132. That is, the flexible protective body 11 covers most of the connection area between the brain electrode 12 and the printed circuit board 13, most of the lead wire area 122, and most of the area on the printed circuit board 13 except for the connector 131. This satisfies the requirement that the array of electrode contacts and the connector 131 on the printed circuit board 13 remain clean and exposed, enabling normal signal transmission. By ensuring that the signal acquisition and transmission functions are not affected, the flexible protective body 11 achieves selective reinforcement and protection of the critical vulnerable areas of the brain electrode implant 1, thereby forming a brain electrode implant 1 that is both flexible, functionally complete, and robust.

[0066] In some embodiments, combined with Figure 6 and Figure 9 As shown, preferably, the portion of the flexible protective body 11 that covers part of the conductor region 122 forms a first portion 111; the portion of the flexible protective body 11 that covers the connection region forms a second portion 112, and the thickness of the second portion 112 is greater than the thickness of the first portion 111.

[0067] It should be noted that the flexible protective body 11 adopts a non-uniform coating thickness design. The second part 112 is thicker to provide robust protection for the key stress points of the connection area. At the same time, the first part 111 is thinner to facilitate the deformation of the lead wire area 122. This allows the brain electrode implant 1 to withstand external forces as a whole and to fit perfectly with the cerebral cortex, reducing long-term stimulation of brain tissue.

[0068] Optionally, the first part 111 and the second part 112 are transitioned by a curved surface. The smooth transition between the first part 111 and the second part 112 of the flexible protective body 11 avoids stress concentration and ensures the structural integrity of the flexible protective body 11 on the one hand; on the other hand, it prevents the formation of sharp edges between the first part 111 and the second part 112, and the smooth curved surface facilitates the implantation of the brain electrode implant 1 into the brain.

[0069] Optionally, combined Figure 9 As shown, for example, the first part 111 has an overall shape that is a cuboid adapted to the wire region 122 of the brain electrode 12. The length ranges from 12mm to 16mm, specifically 12mm, 13mm, 14mm, 15mm, 16mm, and any two of the aforementioned values; the width ranges from 4mm to 8mm, specifically 4mm, 5mm, 6mm, 7mm, 8mm, and any two of the aforementioned values; and the thickness ranges from 0.3mm to 0.7mm, specifically 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, and any two of the aforementioned values. Optionally, combined Figure 9 As shown, for example, the first part 111 and the second part 112 are transitioned by a curved surface with a radius of R10mm-R100mm, and the curved surface starts 3mm-4mm away from the front end of the first part 111; the purpose is to minimize the impact on the flexibility of the ultra-thin brain electrode 12 itself and the potential interference to signal acquisition, so as to ensure that it can fit with the cerebral cortex with high quality.

[0070] Optionally, combined Figure 9As shown, for example, the second part 112 is a cuboid that is adapted to the connection area where the solder joint area 121 of the brain electrode 12 is superimposed and fixed to the solder pad portion 133 of the printed circuit board 13. The length ranges from 13mm to 17mm, specifically 13mm, 14mm, 15mm, 16mm, 17mm and any two of the aforementioned values; the width ranges from 7mm to 11mm, specifically 7mm, 8mm, 9mm, 10mm, 11mm and any two of the aforementioned values; the thickness ranges from 1mm to 2mm, specifically 1mm, 1.25mm, 1.5mm, 1.75mm, 2mm and any two of the aforementioned values. It is particularly emphasized that the first part 111 and the second part 112 are transitioned by a curved surface with a radius of R10mm-R100mm, which is intended to provide more robust mechanical support and stronger fatigue resistance for the connection area where mechanical stress is more concentrated, so as to significantly improve the overall reliability of the product.

[0071] Optionally, combined Figure 9 As shown, for example, the third part 113 is a cuboid adapted to the main body 132 of the printed circuit board 13, with a length ranging from 75mm to 95mm, specifically 75mm, 80mm, 85mm, 90mm, 95mm, and any two of the aforementioned values; a width ranging from 5mm to 9mm, specifically 5mm, 6mm, 7mm, 8mm, 9mm, and any two of the aforementioned values; and a thickness ranging from 1mm to 2mm, specifically 1mm, 1.25mm, 1.5mm, 1.75mm, 2mm, and any two of the aforementioned values. This design aims to provide continuous rigid support and reliable fluid isolation for the slender signal transmission line body of the printed circuit board 13, preventing the printed circuit board 13 from kinking and breaking during implantation and use, and ensuring the stability of long-term signal transmission.

[0072] Optionally, the brain electrode implant 1 can be made into a flexible protective body 11 using an encapsulation process. The flexible protective body 11 can be made of one or more of the following materials: silicone, silicone-derived materials (such as silicone gel), thermoplastic polyurethane, liquid ionic elastomer, thermoplastic elastomer, and polyvinylidene fluoride. The material should be able to meet the requirements of high biocompatibility, good flexibility and elasticity, good environmental stability, and easy processing. Liquid silicone is preferred for forming the flexible protective body 11.

[0073] It is particularly important to emphasize that the brain electrode implant 1, through the localized setting of a flexible protective body 11 of non-uniform thickness, achieves selective reinforcement protection for mechanically vulnerable areas such as bonding points. Simultaneously, the functional surfaces of the electrode contacts of the brain electrode 12 and the connector 131 of the printed circuit board 13 are free of any adhesive covering, ensuring the functional integrity of the electrode signal acquisition interface and external transmission interface. This fundamentally overcomes the defects caused by overall encapsulation leading to functional failure, fully preserving the functional interface between the contact area 123 and the connector 131 of the printed circuit board 13. While ensuring the integrity of electrode signal acquisition and transmission functions, it successfully solves the industry problem of poor mechanical reliability and insufficient long-term stability of the bonding points and leads of the miniature brain electrode 12. Through the localized encapsulation structure, a robust mechanical anchoring and stress buffer are provided for the most vulnerable bonding points and leads, significantly improving their tensile, bending, and fatigue resistance, thereby greatly extending the service life of the brain electrode implant 1.

[0074] like Figure 10 As shown, this application also provides a corresponding method for preparing a brain electrode implant, which uses the aforementioned encapsulation mold 2 to prepare the brain electrode implant 1. The method for preparing the brain electrode implant includes the following steps: S1. Electrically connect brain electrodes 12 and printed circuit boards 13 to prepare an uncoated product; S2. Coat the upper mold 21 and lower mold 22 of the overmolding mold 2 with flexible fluid; S3. Place the uncoated product on the lower mold 22; S4. The upper mold 21 and the lower mold 22 are joined together, and then heated, cooled and demolded to obtain the brain electrode implant 1.

[0075] It is particularly emphasized that a robust yet flexible protective body 11 with a specific shape is formed in the connection area through simple molding and encapsulation. The excellent consistency brought about by the molding process itself also significantly improves the product yield and performance uniformity. Under the premise of meeting biocompatibility and insulation requirements, effective encapsulation is achieved with low process cost and complexity. This method for preparing brain electrode implants has low equipment requirements, a simple process flow (one-time molding), avoids complex secondary processing (such as laser ablation to remove adhesive), significantly reduces production costs, improves production efficiency and yield, and is very suitable for mass production.

[0076] As specifically noted, for example, the flexible protective body 11 is formed of liquid silicone material, the brain electrode 12 is a flexible cortical electrode, and the printed circuit board 13 is an FPC, for further detailed explanation.

[0077] Preferably, step S1 further includes preparing and pre-treating the product and the overmolding mold 2. The un-overmolded product that has been stacked and fixed is cleaned with alcohol and dried to ensure surface cleanliness. The overmolding mold 2 is cleaned with alcohol. Subsequently, the adhesive is prepared by mixing the two components of liquid silicone in proportion and stirring thoroughly.

[0078] In step S2, to reduce air bubbles, the mixed liquid silicone is centrifuged to remove air bubbles. Then, the cavities of the upper mold 21 and the lower mold 22 in the cleaned mold are coated with liquid silicone. It should be noted that in step S2, a coating strategy of "lower mold 22 as the main agent, upper mold 21 as a supplement, and overall excess" is adopted. First, liquid silicone is coated inside the lower mold cavity 242 of the lower mold 22. Since the lower mold 22 carries the product and has a complex cavity structure (including positioning groove 221, clearance groove 23, etc.), it is necessary to ensure that the adhesive completely covers the bottom surface and side walls of the lower mold cavity 242. When applying the adhesive, the adhesive strip should be continuous and uniform, and the amount should completely fill the lower mold cavity 242 and form an appropriate amount of protrusion. Subsequently, liquid silicone is coated inside the upper mold cavity 241 of the upper mold 21, and an appropriate and uniform silicone layer is applied to the upper mold cavity 241.

[0079] Understandably, the above-mentioned adhesive application strategy has the following advantages: First, it facilitates venting. Sufficient adhesive in the lower mold 22 flows preferentially to the surrounding area and overflow chamber during the initial mold closing stage, thus more effectively expelling air from the molding chamber 24. Compared to uniform adhesive application on the upper mold 21 and lower mold 22, or excessive adhesive application on the upper mold 21, this method provides a superior venting path, significantly reducing the risk of residual air bubbles. Second, it avoids delamination. Sufficient adhesive ensures that the silicone can fully fuse into a single unit under pressure after mold closing, avoiding fusion lines or delamination caused by insufficient adhesive. Third, compared to the process of injecting adhesive after mold closing, for the micron-level precision structure and void-avoiding areas of this product, mold closing before injection requires extremely high injection pressure and precise gate design. This not only involves complex equipment and high costs, but the high-speed injection of adhesive can easily impact and damage the unfixed brain electrode 12. This brain electrode implant preparation method uses simple equipment, is low-cost, and is safer for fragile structures.

[0080] In step S3, the cleaned and dried uncoated product is inserted into the positioning groove 221 of the lower mold 22, ensuring that the edge of the main body 132 of the printed circuit board 13 is completely aligned with the contour of the positioning groove 221. At this time, the contact area 123 of the brain electrode 12 should be precisely located directly above the second limiting groove 232 of the lower mold 22, and the connection area is suspended within the corresponding lower mold cavity groove 242. This "predetermined position" is guaranteed by the structure of the positioning groove 221, thereby ensuring that the brain electrode 12 and the printed circuit board 13 can be stably positioned in the middle of the final molded flexible protective body 1.

[0081] In step S4, the curing temperature range is less than or equal to 125°C. This upper temperature limit is set because excessively high temperatures can affect the performance of the printed circuit board 13 substrate, leading to deformation or damage; while excessively low temperatures can result in insufficient cross-linking of the liquid silicone and incomplete curing. Maintaining the curing temperature within the range of less than or equal to 125°C is a crucial balance between reliable protection of the printed circuit board 13 and sufficient silicone curing. After curing, the encapsulation mold 2 is cooled to a suitable temperature before demolding, and the encapsulated product, i.e., the brain electrode implant 1, is removed. The standardized cooling and demolding procedure after curing includes the following steps: The first step involves transferring the heat-cured overmolding mold 2 from the heating station to a dedicated cooling platform for forced cooling. Through air cooling and heat conduction via contact with the cooling platform, the overall temperature of the overmolding mold 2 is uniformly reduced to below 40°C. This step aims to ensure that the silicone has fully cured and achieved stable mechanical properties, while preventing thermal deformation of the product caused by high-temperature demolding.

[0082] The second step is to move the overmolding mold 2 to the workbench after cooling for subsequent demolding operations.

[0083] Third, remove the fastening screws 26 used to fix the upper mold 21 and the lower mold 22, releasing the mechanical locking of the overmolding mold 2. Using the positioning pins 222 of the overmolding mold 2 as guides, screw in the ejector screw through the first threaded hole 211. As the ejector screw is screwed in, the ejection force it generates will act evenly on the lower mold 22, thereby overcoming any possible vacuum suction force and friction between materials, achieving a smooth and stable separation of the upper mold 21 and the lower mold 22.

[0084] Fourth step: After the upper mold 21 and the lower mold 22 are separated, the final product that has been coated with glue is taken out from the lower mold cavity 242. During this process, care should be taken to protect the contact area of ​​the brain electrode 12.

[0085] The fifth step is to perform post-processing on the product (such as trimming burrs) and clean the overmolding mold 2 for future use.

[0086] In some embodiments, combined with Figure 11 As shown, this application also provides a brain-computer interface system, including an EEG amplifier 3, an EEG acquisition device 4, a host computer 5, and the aforementioned brain electrode implant 1, which are electrically connected to each other.

[0087] Specifically, the EEG implant 1 is surgically implanted into the cerebral cortex, contacting brain tissue to collect EEG signals or provide appropriate stimulation when needed. Using the aforementioned EEG implant 1 improves its connection strength, lifespan, and reliability. The EEG amplifier 3 connects to the EEG implant 1 and preprocesses the collected EEG signals, including amplification, filtering, and analog-to-digital conversion of weak EEG signals. The EEG acquisition unit 4 connects to the EEG amplifier 3 and performs secondary processing on the preprocessed EEG signals, including serial-to-parallel data conversion, preliminary data screening, data frame construction, data buffering, and data transmission conversion. The host computer 5 communicates with the EEG acquisition unit 4, managing and controlling the entire system, receiving data from the EEG amplifier 3 and the EEG acquisition unit 4, processing, visualizing, and making decisions, and sending instructions to the EEG amplifier 3 and the EEG acquisition unit 4.

[0088] Note that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of this application, the scope of which is determined by the scope of the appended claims.

Claims

1. A rubber overmolding mold, characterized in that, Used to prepare a brain electrode implant, the brain electrode implant comprising a printed circuit board (13) and brain electrodes (12). The overmolding mold includes an upper mold (21) and a lower mold (22). The upper mold (21) is provided with an upper mold cavity (241), and the lower mold (22) is provided with a lower mold cavity (242). The upper mold (21) is detachably connected to the lower mold (22). The upper mold cavity (241) and the lower mold cavity (242) form a molding chamber (24). The overmolding mold is provided with a positioning groove (221) for embedding the main body (132) of the printed circuit board (13), and the overmolding mold is also provided with a clearance groove (23) for accommodating the contact area (123) of the brain electrode (12). The positioning groove (221), the molding chamber (24) and the clearance groove (23) are arranged in sequence.

2. The overmolding mold according to claim 1, characterized in that, The molding chamber (24) includes a first receiving area for accommodating the connection area of ​​the brain electrode implant and a second receiving area for accommodating a portion of the wire area (122) of the brain electrode (12). The spacing of the first receiving area along the thickness direction of the brain electrode (12) is greater than the spacing of the second receiving area along the thickness direction of the brain electrode (12).

3. The overmolding mold according to claim 2, characterized in that, The inner walls of the first and second accommodating areas are transitioned by curved surfaces.

4. The overmolding mold according to claim 1, characterized in that, The lower mold (22) is provided with the positioning groove (221), which is located at the bottom end of the lower mold cavity (242), and the depth of the positioning groove (221) is shallower than that of the lower mold cavity (242).

5. The overmolding mold according to claim 1, characterized in that, The upper mold (21) is provided with a first limiting groove (231), and the lower mold (22) is provided with a second limiting groove (232). The first limiting groove (231) and the second limiting groove (232) form the clearance groove (23). And / or, the spacing of the clearance groove (23) along the thickness direction of the brain electrode (12) is in the range of 3mm-7mm.

6. The overmolding mold according to claim 1, characterized in that, The overmolding mold is provided with an overflow cavity, which is located on both sides of the molding cavity (24). The lower mold (22) is provided with a lower mold overflow groove (252), which is located on the periphery of the lower mold cavity (242). The upper mold (21) is provided with an upper mold overflow groove (251), which is located on the periphery of the upper mold cavity (241). The lower mold overflow groove (252) and the upper mold overflow groove (251) together constitute the overflow cavity.

7. The overmolding mold according to any one of claims 1-6, characterized in that, One of the upper mold (21) and the lower mold (22) is provided with multiple positioning pins (222), and the other is provided with multiple positioning holes (212). The positioning pins (222) and the positioning holes (212) correspond one to one, and the positioning pins (222) can pass through the positioning holes (212). And / or, the upper mold (21) and the lower mold (22) are detachably connected by fastening screws; And / or, it also includes an ejector screw, wherein the upper mold (21) is provided with a first threaded hole (211), the ejector screw being threaded into the first threaded hole (211) and capable of pushing against the lower mold (22).

8. A brain electrode implant, characterized in that, The brain electrode implant is prepared using the encapsulation mold described in any one of claims 1-7; The brain electrode implant includes a flexible protective body (11), a brain electrode (12), and a printed circuit board (13). The brain electrode (12) is provided with a solder joint area (121), and the printed circuit board (13) is provided with a pad portion (133). The solder joint area (121) is electrically connected to the pad portion (133) and forms a connection area. The flexible protective body (11) covers at least the connection area.

9. A method for preparing a brain electrode implant, characterized in that, The brain electrode implant is prepared using the overmolding mold as described in any one of claims 1-7, and the method for preparing the brain electrode implant includes the following steps: The brain electrodes (12) and the printed circuit board (13) are electrically connected to prepare an uncoated product; The upper mold (21) and lower mold (22) of the mold are coated with flexible fluid; Place the uncoated product on the lower mold (22); The upper mold (21) and the lower mold (22) are joined together, and then heated, cooled and demolded to obtain the brain electrode implant.

10. A brain-computer interface system, characterized in that, It includes an EEG amplifier (3), an EEG acquisition device (4), a host computer (5), and an EEG implant as described in claim 8, all electrically connected to each other.

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