Injection molding method

Abstract

The present disclosure relates to an injection molding method, which comprises: preparing a mold and a flexible film, the mold comprising an upper mold having a first recess, and a lower mold cooperating with the upper mold and having a second recess for arranging the flexible film, arranging the flexible film in the lower mold, the first recess being provided with a protruding platform protruding from the bottom of the first recess, the lower mold being provided with an injection port for providing an injection material and communicating with the second recess; closing the upper mold and the lower mold to form a mold cavity; selecting an injection material having a density greater than that of the flexible film, injecting the injection material into the mold cavity through the injection port, causing the flexible film to float under the buoyancy of the injection material, and causing the surface of the flexible film to fit the edge of the protruding platform; and allowing the injection material to solidify and form. According to the present disclosure, an injection molding method is provided, which facilitates the positioning of the film to be injected in the mold and forms a specific shape.

Description

[0001] The present application is a divisional application of the patent application No. CN201910793899.X with the title of Injection Molding Method of Flexible Film with Stimulating Electrode, filed on August 27, 2019. TECHNICAL FIELD

[0002] The present disclosure relates to an injection molding method. BACKGROUND

[0003] In the field of medical devices, many sensing components or structural components need to be injection molded with silicone to meet the biological compatibility. For example, for implantable medical devices, stimulating components with stimulating electrodes are often provided, wherein the stimulating electrode area needs to be exposed for stimulating the implanted site, and the stimulating component needs to be injection molded into a specific shape according to the use environment.

[0004] In the existing injection molding of stimulating components, a stimulating component with stimulating electrodes prepared in advance is loaded into a mold, then liquid silicone material is injected, and the liquid silicone is combined with the stimulating component to solidify, thereby being injection molded into a product with a specific shape. In order to form the stimulating component into a specific shape, it is usually necessary to pre-bond the stimulating electrode area to the inner surface of the mold cavity or to be adsorbed to the inner surface, so as to avoid being covered by the liquid silicone, while forming a specific shape after solidification.

[0005] However, in the above prior art, if the stimulating electrode area is pre-bonded to the inner surface of the mold, the stimulating electrode surface needs to be coated with adhesive, and it needs to be separated from the mold after insert molding, at this time, the stimulating electrode is more likely to tear or fall off, thereby affecting its use performance. The use of adsorption to fix the stimulating electrode area has difficulties in the size setting of the adsorption hole and the control of the vacuum adsorption force. SUMMARY

[0006] The present disclosure is completed in view of the above-mentioned prior art, and aims to provide an injection molding method of flexible film with stimulating electrodes which can be conveniently positioned and formed into a specific shape.

[0007] To this end, the present disclosure provides an injection molding method of a flexible film having a stimulating electrode, which includes: a configuration process of preparing an upper mold having a first recess and a lower mold which is fitted to the upper mold and in which a flexible film having a stimulating electrode is disposed, wherein a projection having a prescribed curvature is provided from a bottom of the first recess, and an injection port which supplies an injection material is provided in the lower mold; a mold closing process of closing the upper mold and the lower mold and forming a mold cavity; a positioning process of injecting the injection material into the mold cavity through the injection port, and making the flexible film float and adhere to the projection; and a molding process of maintaining the upper mold and the lower mold, and heat-treating the upper mold and the lower mold to solidify and mold the injection material.

[0008] In the present disclosure, the flexible film is disposed in a mold cavity formed by an upper mold and a lower mold, and an injection material is injected into the mold cavity, in which case the flexible film can be made to float and adhere to a projection by the buoyancy of the injection material, and then the upper mold and the lower mold are maintained and heat-treated. Thus, the injection material can be coated on other portions of the flexible film which do not adhere to the projection.

[0009] In the injection molding method provided by the present disclosure, in the positioning process, the flexible film can be made to closely adhere to the projection by filling the mold cavity with the injection material. In this case, the portion of the flexible film which adheres to the projection can not be coated with the injection material, and the other portions of the flexible film can be sufficiently coated with the injection material.

[0010] In the injection molding method provided by the present disclosure, the flexible film can include a stimulating portion having a stimulating electrode and a connecting portion electrically connected to the stimulating portion, and in the positioning process, the stimulating portion of the flexible film can be made to float and adhere to the projection. In this case, the stimulating portion having the stimulating electrode can be connected to the connecting portion, and the stimulating portion can be coated with the injection material.

[0011] In the injection molding method provided by the present disclosure, in the mold closing process, a gap between the projection and the lower mold can be greater than the thickness of the flexible film. Thus, the flexible film can be better coated.

[0012] In the injection molding method provided by the present disclosure, the flexible film can have a functional region including a stimulating electrode and a non-functional region, and in the positioning process, the functional region can be covered by the projection. In this case, the functional region of the flexible film can not be coated with the injection material, and thus the functional region of the flexible film can better perform its function.

[0013] In the injection molding method provided by the present disclosure, optionally, the non-functional area of the flexible film has a gap with the bottom of the first groove, and the injection material covers the gap in the positioning process. Thus, the non-functional area of the flexible film can be fully covered by the injection material.

[0014] In the injection molding method provided by the present disclosure, optionally, in the molding process, the flexible film is molded into a curved shape with the specified curvature. Thus, the flexible film can be better adapted to different process requirements.

[0015] In the injection molding method provided by the present disclosure, optionally, a plurality of injection ports are provided in the lower mold, and the flexible film covers the plurality of injection ports. In this case, the injection material can enter the mold cavity from the lower mold, and thus the flexible film can float under the buoyancy of the injection material.

[0016] In the injection molding method provided by the present disclosure, optionally, a second groove for arranging the flexible film is provided in the lower mold. Thus, the flexible film can be arranged in the lower mold.

[0017] In the injection molding method provided by the present disclosure, optionally, the bottom of the second groove is in the form of a protrusion with the specified curvature. In this case, the flexible film can be solidified and molded into different shapes, and thus the flexible film can be better adapted to different process requirements.

[0018] According to the present disclosure, an injection molding method for a flexible film with stimulating electrodes that can be conveniently positioned and formed into a specific shape is provided. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 FIG. 1 is a flowchart illustrating an injection molding method according to an embodiment of the present disclosure.

[0020] Figure 2 FIG. 2 is a structural diagram illustrating a mold after clamping according to an embodiment of the present disclosure.

[0021] Figure 3 FIG. 3 is a structural diagram illustrating a mold after separation according to an embodiment of the present disclosure.

[0022] Figure 4 FIG. 4 is a structural diagram illustrating a mold after clamping according to another embodiment of the present disclosure. Figure 3 FIG. 5 is a partial structural diagram illustrating a second groove according to an embodiment of the present disclosure.

[0023] Figure 5 FIG. 6 is an application diagram illustrating an injection molding method according to an embodiment of the present disclosure.

[0024] Figure 6 FIG. 7 is an application diagram illustrating an injection molding method according to another embodiment of the present disclosure.Figure 5 A partial view of a mold cavity.

[0025] Figure 7 is a cross-sectional view of a mold showing a flexible film positioned on a projection according to an embodiment of the present disclosure. Figure 5 A cross-sectional view of a mold after the mold is closed and injection of an injection material.

[0026] Figure 8 is a cross-sectional view of a mold showing a flexible film positioned on a projection according to an embodiment of the present disclosure.

[0027] BRIEF DESCRIPTION OF DRAWINGS

[0028] 1… mold, 10… upper mold, 10a… first abutting surface, 11… first recess, 11a… bottom, 12… projection, 20… lower mold, 20a… second abutting surface, 21… second recess, 21a… bottom, 22… support mechanism, 110… injection channel, 110a1, 110a2… sub-channel, 110a… injection hole, 111, 112… injection port, 30… flexible film, 30a… upper surface, 30b… lower surface, 310… stimulation portion, 311… functional region, 320… connecting portion, 321… through-hole, 40… mold cavity. DETAILED DESCRIPTION

[0029] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, for the sake of explanation, identical configurations are designated by identical reference numerals, and repetitive explanations are omitted. In addition, the drawings are schematic views, and the ratio of the dimensions of the components to each other or the shape of the components, etc. can be different from the actual.

[0030] In addition, the subheadings and the like involved in the following description of the present disclosure are not intended to limit the content or the scope of the present disclosure, but merely serve as a reading aid. Such subheadings should not be understood as dividing the content of the article, nor should the content under the subheading be limited only within the scope of the subheading.

[0031] The injection molding method according to the present disclosure is an injection molding method of a flexible film having a stimulation electrode (hereinafter also referred to simply as "the injection molding method"). In the injection molding method according to the present disclosure, a flexible film having a stimulation electrode is arranged in a mold and an injection material is injected into the mold, so that the flexible film is caused to float up in the mold by the buoyancy of the injection material and adhere to the mold to form a shape having a prescribed curvature, and then the mold is subjected to heat treatment, thereby injection molding the flexible film. Hereinafter, a specific embodiment of the present disclosure will be described in detail with reference to the drawings.

[0032] In the present disclosure, the flexible film can be applied in the field of medical devices, for example, the flexible film can be applied to a retinal electrical stimulator, which can include an implanted part and an extracorporeal part. The flexible film can be applied to the implanted part of the retinal electrical stimulator. The flexible film can be a flexible film with stimulating electrodes, and the retina can be stimulated by the stimulating electrodes. Therefore, the flexible film needs to be injection molded to meet the biological compatibility. The flexible film can be shaped into a specific shape, and the stimulating electrodes on the flexible film will not be covered.

[0033] The injection molding method related to the present disclosure is particularly suitable for injection molding of flexible objects such as flexible films. By arranging the injection molding object in the mold and injecting the injection molding material into the mold, the injection molding object is floated in the mold under the buoyancy of the injection molding material and attached to the mold to form a shape with a specified curvature, and then the mold is heat treated to injection mold the injection molding object.

[0034] Figure 1 is a flowchart showing the injection molding method related to the embodiment of the present disclosure.

[0035] In the present embodiment, as shown in Figure 1 , the injection molding method can include the following steps: a configuration process, preparing an upper mold 10 with a first groove 11 and a lower mold 20 cooperating with the upper mold 10, and arranging a flexible film 30 with stimulating electrodes in the lower mold 20, wherein a protruding platform 12 with a specified curvature is provided in the first groove 11 from the bottom 11a of the first groove 11, and an injection port for providing injection molding material is provided in the lower mold 20 (step S10); a mold closing process, closing the upper mold 10 and the lower mold 20 to form a mold cavity 40 (step S20); a positioning process, injecting the injection molding material into the mold cavity 40 through the injection port to make the flexible film 30 float and adhere to the protruding platform 12 (step S30); and a molding process, holding the upper mold 10 and the lower mold 20, and heat treating the upper mold 10 and the lower mold 20 to solidify the injection molding material (step S40).

[0036] In step S10, as described above, the upper mold 10 with the first groove 11 and the lower mold 20 cooperating with the upper mold 10 can be prepared, and the flexible film 30 with stimulating electrodes can be arranged in the lower mold 20, wherein the protruding platform 12 with a specified curvature is provided in the first groove 11 from the bottom 11a of the first groove 11 (see Figure 3 ), and the injection port for providing injection molding material is provided in the lower mold 20 (in the present embodiment, the injection port 111 and the injection port 112, see Figure 7 ).

[0037] Figure 2is a structural schematic diagram showing the mold after the mold is closed, which is involved in the embodiment of the present disclosure. Figure 3 is a structural schematic diagram showing the mold after the mold is separated, which is involved in the embodiment of the present disclosure. Figure 4 is a structural schematic diagram showing Figure 3 is a partial schematic diagram of the second groove.

[0038] In some examples, as Figure 2 As shown, the upper mold 10 and the lower mold 20 can be assembled to form the mold 1, that is, in step S10, the mold 1 including the upper mold 10 and the lower mold 20 can be used. In some examples, the upper mold 10 can be fixed together with the lower mold 20, for example, by screwing.

[0039] In the embodiment, the shape of the mold 1 is not particularly limited, for example, it can be a cuboid, a cylinder, a cube or an irregular three-dimensional structure.

[0040] In some examples, the upper mold 10 has a first abutting surface 10a, and the lower mold 20 has a second abutting surface 20a abutting with the first abutting surface 10a. In other words, the first abutting surface 10a of the upper mold 10 and the second abutting surface 20a of the lower mold 20 can be abutted to assemble the mold 1.

[0041] In some examples, as Figure 3 As shown, a first groove 11 can be formed on the first abutting surface 10a. In some examples, the first groove 11 can have a bottom 11a.

[0042] In some examples, as Figure 3 As shown, a first groove 11 can be formed on the first abutting surface 10a. In some examples, the shape of the bottom 11a of the first groove 11 is not particularly limited. For example, the shape of the bottom 11a of the first groove 11 can be a plane, or an arc surface, etc.

[0043] In some examples, the flexible film 30 can have an upper surface 30a and a lower surface 30b. Wherein, the upper surface 30a can face the upper mold 10, and the lower surface 30b can face the lower mold 20. In some examples, the stimulating electrode as described above can be arranged on the upper surface 30a of the flexible film 30, and form a functional area 311 (for example, a stimulating electrode area) on the upper surface 30a. In some examples, the protrusion 12 can also not be arranged on the first groove 11, in which case the stimulating electrode area can be directly attached to the bottom 11a of the first groove 11.

[0044] In some examples, the first groove 11 may have a bottom 11a with a specified curvature. In some examples, during the positioning process described above, the flexible film 30 may be attached to the bottom 11a of the first groove 11, thereby enabling the side of the flexible film 30 that is attached to the bottom 11a of the first groove 11 to be formed into a curved surface with the same curvature as the bottom 11a of the first groove 11.

[0045] In some examples, the first groove 11 may be provided with a protrusion 12 that protrudes from the bottom 11a of the first groove 11. In this case, during the above positioning process, the flexible film 30 can be lifted and attached to the protrusion 12, thereby preventing the portion of the flexible film 30 that is attached to the protrusion 12 from being covered by the injection molding material.

[0046] In some examples, the protrusion 12 may have an upper surface 12a with a defined curvature. In some examples, the upper surface 12a of the protrusion 12 is concave. This allows the portion of the flexible film 30 that adheres to the protrusion 12 to be shaped into a curved surface with the same curvature as the upper surface 12a of the protrusion 12. In some examples, the curvature of the upper surface 12a of the protrusion 12 may be the same as the curvature of the bottom 11a of the first groove 11.

[0047] In some examples, such as Figure 3 and Figure 4 As shown, a second groove 21 may be formed on the second mating surface 20a. In some examples, the second groove 21 may have a bottom 21a. In some examples, the shape of the bottom 21a of the second groove 21 is not particularly limited. For example, the shape of the bottom 21a of the second groove 21 may be a plane or a curved surface, etc.

[0048] In some examples, the bottom 21a of the second groove 21 can be a protrusion with a predetermined curvature. In this case, during the molding process, the side of the flexible film 30 facing the bottom 21a of the second groove 21 can cover the injection molding material, thereby molding it into a curved surface with the same curvature as the bottom 21a of the second groove 21. In some examples, the predetermined curvature can match the curvature of the bottom 11a of the first groove 11, thereby molding the flexible film 30 into a curved surface with the same curvature as the injection molded product covering the upper surface 30a and the injection molded product covering the lower surface 30b. In some examples, during the molding process (step S40, described later), the flexible film 30 can be molded into a curved surface with a predetermined curvature. This allows the flexible film 30 to be molded into a molded article with a specific shape.

[0049] Figure 5 This is a schematic diagram illustrating the application of the injection molding method according to the embodiments of this disclosure. Figure 6 yes Figure 5 A partial schematic diagram of the mold cavity is shown.Figure 7 This illustrates the embodiments involved in this disclosure. Figure 5 A cross-sectional diagram of the mold after mold closing and injection of the injection molding material.

[0050] In some examples, the second groove 21 can be used to configure the flexible film 30, for example, as Figure 5 As shown, it can be along Figure 5 The direction of the middle arrow A indicates that the flexible film 30 is disposed in the second groove 21 of the lower mold 20. This allows the flexible film 30 to be disposed in the lower mold 20. In some examples, the flexible film 30 may be disposed in the lower mold 20 along a direction parallel to the second mating surface 20a of the lower mold 20.

[0051] In some examples, such as Figure 5 to Figure 7 As shown, the flexible film 30 may include a stimulation portion 310 and a connecting portion 320 connected to the stimulation portion 310. In some examples, the connecting portion 320 may be electrically connected to the stimulation portion 310, and the stimulation portion 310 may have a functional region 311. In some examples, the functional region 311 may have a stimulation electrode. In this case, the stimulation portion 310 with the stimulation electrode may be connected to the connecting portion 320. In some examples, the functional region 311 may be located on the upper surface 30a of the flexible film 30. In some examples, during the mold closing process, the side of the flexible film 30 with the functional region 311 (i.e., the upper surface 30a) may face the mold 10.

[0052] In some examples, such as Figure 5 As shown, the flexible film 30 can be in the form of a sheet. In some examples, the flexible film 30 can be other regular block, spherical, or irregular arbitrary shapes. In some examples, the size of the flexible film 30 can match the size of the second groove 21. For example, the size of the flexible film 30 can be smaller than the size of the second groove 21. This allows the flexible film 30 to be easily disposed in the second groove 21.

[0053] In some examples, the flexible film 30 can be made of a flexible material. This facilitates the bonding of the flexible film 30 to the mold 1 and its shaping into different forms (described later). In some examples, the flexible film 30 can be made of a flexible insulating material. In this case, electrical interference from the flexible film to other devices can be effectively reduced. In some examples, the flexible film 30 can be made of at least one selected from polyimide, polydimethylsiloxane, and polychloro-p-xylene. This allows for the acquisition of a biocompatible flexible film 30, making it better suited for use in the medical device field.

[0054] In some examples, the lower mold 20 can be provided with an injection port. In some examples, the injection material can be injected into the lower mold 20 (e.g., the second recess 21) through the injection port. For example, as shown in FIG. 1 1, the injection port (e.g., the injection port 1 1 1 and the injection port 1 12) can be provided at the bottom 21 a of the second recess 21. Figure 7

[0055] In step S20, the upper mold 10 and the lower mold 20 can be closed and the mold cavity 40 can be formed, as described above. In some examples, the mold cavity 40 can include a cavity portion 41 and an extension portion 42 in communication with the cavity portion 41. In this case, the cavity portion 41 and the extension portion 42 collectively form the mold cavity 40 of the mold 1. In addition, in some examples, the above-mentioned boss 12 can be formed in the cavity portion 41.

[0056] In some examples, as shown in FIG. 1 1, in step S20, the flexible film 30 can be disposed in the lower mold 20, the upper mold 10 and the lower mold 20 can be closed in the direction indicated by the arrow A in FIG. 1 1, and the mold cavity 40 can be formed. Figure 5 to Figure 7 Figure 5 In some examples, as shown in FIG. 1 1, in step S20, the flexible film 30 can be disposed in the lower mold 20, the upper mold 10 and the lower mold 20 can be closed in the direction indicated by the arrow A in FIG. 1 1, and the mold cavity 40 can be formed.

[0057] As described above, after the upper mold 10 and the lower mold 20 are assembled to form the mold 1, the first recess 1 1 and the second recess 21 can combine to form the mold cavity 40. In some examples, the shape and size of the mold cavity 40 can be determined by the shape and size of the first recess 1 1 and the second recess 21. In some examples, the injection material can cover the edges of the flexible film 30. For example, the edges of the flexible film 30 can have a gap with the mold cavity 40. In some examples, the gap between the boss 12 and the lower mold 20 can be greater than the thickness of the flexible film 30. In this case, the flexible film 30 can be better covered by the injection material in the presence of the boss 12. In this case, during the injection of the injection material to the flexible film 30, the injection material covers not only the lower surface 30b of the flexible film 30 but also the edges of the upper surface 30a, whereby the edges of the flexible film 30 are covered by the injection material.

[0058] ​​In some examples, when the flexible film 30 including the stimulation portion 310 having the stimulation electrode and the connection portion 320 connected to the stimulation portion 310 is placed in the cavity 40 of the mold 1, the stimulation portion 310 can be arranged in the cavity portion 41, and the connection portion 320 can be arranged in the extension portion 42. In the injection molding of the flexible film 30 in the cavity 40, the connection portion 320 of the flexible film 30 is supported and fixed (described later) by the support mechanism 22 (for example, a plurality of support mechanisms) of the first groove 11 and the second groove 21, respectively, and the stimulation portion 310 of the flexible film 30 is adhered and positioned by the injection material of the upper mold 10, thereby enabling the flexible film 30 to be molded into a specific shape of the injection molded product.

[0059] Figure 8 FIG. 4 is a cross-sectional view showing a mold in which a flexible film according to an embodiment of the present disclosure is positioned on a projection.

[0060] In step S30, as described above, the injection material 50 can be injected into the cavity 40 through the injection port, so that the flexible film 30 is floated and adhered to the projection 12.

[0061] In some examples, in step S30, the injection material 50 (see FIG. 4) can be injected into the cavity 40 through the injection port (for example, the injection port 111 and the injection port 112). Figure 7 and Figure 8 Specifically, in some examples, the flexible film 30 can be floated and adhered to the mold 1 by the buoyancy of the injection material 50 (for example, liquid silicone).

[0062] In the positioning process (step S30), the injection material 50 can be selected from a material having a density greater than that of the flexible film 30. Thus, the flexible film 30 can be better floated by the buoyancy of the injection material 50. In some examples, the injection material 50 can include plastic or liquid silicone. Thus, the injection material 50 can be better coated on the surface of the flexible film 30. In some examples, the plastic and liquid silicone used can have biocompatibility. In some examples, the plastic can be selected from at least one of polylactic acid and polyurethane, thereby enabling the flexible film 30 to be better applied in the medical device field.

[0063] In some examples, the mold 1 can be provided with a glue injection hole 110a. In some examples, as shown in Figure 2 , the glue injection hole 110a can be provided in the upper mold 10. In this case, the injection material 50 can enter the cavity 40 through the glue injection hole 110a.

[0064] In some examples, the mold 1 is provided with an injection channel 110 connected to the injection hole 110a. In some examples, the injection material 50 can be injected from the injection hole 110a, and the injection material 50 can flow along the injection channel 110 after entering the injection hole 110a.

[0065] In addition, in some examples, the injection channel 110 can be in communication with the mold cavity 40 to form an injection port (e.g., injection port 111 or injection port 112). In this case, the injection material 50 can enter the mold cavity 40 from the injection port 111 and the injection port 112 along the injection channel 110 (see Figure 7 ).

[0066] In the positioning process (step S30), the injection material 50 can be injected from the injection hole 110a into the mold cavity 40 (e.g., injected into the injection hole 110a in the direction of gravity), and the injection material 50 can flow along the injection channel 110 after entering the injection hole 110a. The injection channel 110 can change the flow direction of the injection material 50, enabling the injection material 50 to enter the mold cavity 40 from the injection port (e.g., injection port 111 or injection port 112) via the sub-channel 110a1 and the sub-channel 110a2. In this case, since the injection material 50 entering the mold cavity 40 is subjected to the action of gravity, the flexible film 30 arranged above the injection port 111 or the injection port 112 is blocked after entering the mold cavity 40 and flows along the lower surface 30b of the flexible film 30, and gradually supports the lower surface 30b of the entire flexible film 30. The flexible film 30 is floated by the buoyancy of the injection material 50, and in turn the upper surface 30a of the flexible film 30 is attached to the mold 1, thereby positioning the flexible film 30 into a specific shape.

[0067] In some examples, the injection port can be one or multiple (e.g., injection port 111 and injection port 112). In Figure 7 the example shown, the second groove 21 can form the injection port 111 and the injection port 112.

[0068] In some examples, the injection channel 110 can be divided into multiple sub-channels in the mold 1, and the multiple sub-channels can be in communication with the mold cavity 40 to form multiple injection ports. For example, as shown in Figure 7 and Figure 8 the injection channel 110 can be divided into two sub-channels (sub-channel 110a1 and sub-channel 110a2) in the mold 1, and the two sub-channels 110a1 and 110a2 can be in communication with the mold cavity 40. In some examples, the injection ports 111 and 112, which are the flow outlets of the two sub-channels 110a1 and 110a2, can be provided at the bottom 21a of the second groove 21.

[0069] In some examples, the bottom 21a of the second recess 21 can be provided with a plurality of injection ports (e.g., the injection port 111 and the injection port 112) as described above. In some examples, the bottom 21a of the second recess 21 can be provided with a plurality of injection ports. In some examples, the flexible film 30 disposed in the second recess 21 can cover the plurality of injection ports (e.g., the injection port 111 and the injection port 112) described above. In this case, the injection of the injection material 50 from the lower mold into the mold cavity 40 can be enabled, and the flexible film can be caused to float by the buoyancy of the injection material 50 and thereby adhere to the mold 1.

[0070] In some examples, the injection hole 110a can be one or a plurality. In some examples, the injection hole 110a can be provided in the upper mold 10 and / or the lower mold 20. In this case, it can be better adapted to the process requirements of different molding processes, thereby facilitating subsequent injection of the injection material 50 into the mold cavity 40.

[0071] In some examples, the viscosity of the injection material 50 can be 10-100 million Pascal seconds. Preferably, the viscosity of the injection material 50 can be 30-60 million Pascal seconds. In this case, the viscosity of the injection material 50 is controlled within a certain range, which can not only satisfy the sufficient flowability of the injection material 50, but also effectively inhibit the occurrence of problems such as leakage, thereby optimizing the molding process and being more conducive to the injection molding of the flexible film 30.

[0072] In some examples, the size of the buoyancy of the injection material can be adjusted by controlling the injection rate of the injection material 50. In some examples, the size of the buoyancy generated by the injection material 50 can be equivalent to the size of the buoyancy generated by 0.8-0.9 kPa of atmospheric pressure. In this way, the size of the buoyancy can be adjusted to facilitate the flexible film 30 to be better adhered to the mold 1.

[0073] In some examples, the injection amount of the injection material 50 can be adjusted according to the size of the mold cavity 40. In this way, the process requirements of the flexible film 30 can be met. In some examples, in step S30, the injection material 50 can be caused to fill the mold cavity 40.

[0074] In some examples, the flexible film 30 can include a functional area 311 (see Figure 5 ) and a non-functional area. For example, the functional area 311 of the flexible film 30 can be an area with a stimulating electrode (i.e., the stimulating electrode area described above), and the non-functional area can be other areas of the flexible film 30 that do not contain the functional area 311.

[0075] In some examples, the functional area 311 of the flexible film 30 can not be covered by the injection material 50, and the non-functional area can be covered by the injection material 50. In some examples, the injection material 50 can enter the mold cavity 40 through the glue inlet, and the side of the flexible film 30 with the functional area 311 (for example, the upper surface 30a of the flexible film) can be arranged in the mold 1 in a manner determined by the manner in which the injection material 50 enters the mold cavity 40. For example, the injection material 50 can enter the mold cavity 40 from the bottom 21a of the second groove 21, and the side of the flexible film 30 with the functional area 311 can face the bottom 11a of the first groove 11. In this case, when the injection material 50 enters the mold cavity 40, the flexible film 30 is lifted by the injection material 50 and adheres to the mold 1 (for example, the bottom 11a of the first groove 11 or the protrusion 12). In this way, the functional area 311 of the flexible film 30 can not be covered by the injection material 50.

[0076] In some examples, the side of the flexible film 30 with the functional area 311 can also have a non-functional area that can be covered by the injection material. In some examples, the bottom 11a of the first groove 11 can be provided with a protrusion 12 that matches the functional area 311. In some examples, when the flexible film 30 is lifted by the injection material 50 and adheres to the mold 1, the functional area 311 can be covered by the protrusion 12. In this case, the functional area 311 of the flexible film 30 can not be covered by the injection material. In some examples, the functional area 311 can completely coincide with the surface of the protrusion 12, that is, the edge of the protrusion 12 can adhere to the surface of the flexible film 30 on the side of the functional area 311. In some examples, there can be a gap between the non-functional area on the same side of the flexible film 30 as the functional area 311 and the bottom 11a of the first groove 11. In this case, the functional area 311 of the flexible film 30 can not be covered by the injection material 50, and the non-functional area can be covered by the injection material 50.

[0077] In some examples, the gap between the protrusion 12 and the lower mold 20 can be greater than the thickness of the flexible film 30. In this case, the flexible film 30 can be better covered by the injection material 50 in the presence of the protrusion 12.

[0078] In some examples, the flexible film 30 is lifted by the injection material 50 and adheres to the mold 1, and there can be a gap between the flexible film 30 and the bottom 21a of the second groove 21. In this way, the non-functional area of the flexible film 30 can be covered by the injection material.

[0079] In some examples, as Figure 5 to Figure 7As shown, the flexible film 30 may include a stimulating portion 310 and a connecting portion 320 connected to the stimulating portion 310. In some examples, the connecting portion 320 may be electrically connected to the stimulating portion 310. In some examples, during the positioning process, the stimulating portion 310 may be tightly fitted to the mold 1. In this case, the portion of the stimulating portion 310 that is fitted to the mold 1 is not covered by the injection molding material, while the other portions of the stimulating portion 310 are fully covered by the injection molding material.

[0080] In some examples, the connecting portion 320 may be covered by injection molding material, but the connecting portion 320 may not undergo a change in shape. In some examples, the connecting portion 320 may have several through holes 321. In some examples, such as Figure 5 to Figure 7 As shown, after the mold closing process, the connecting part 320 can be fixed in the mold cavity 40. For example, as Figure 3 to Figure 7 As shown, the bottom 11a of the first groove 11 and the bottom 21a of the second groove 21 can each be provided with a support mechanism 22 that matches the through hole 321 on the connecting portion 320. In this case, after the mold closing process, the connecting portion 320 can be fixed in the mold cavity 40 by using the through hole 321 and the support mechanism 22 that matches the through hole 321, thereby preventing the connecting portion 320 from changing shape under the action of the injection molding material 50 during the positioning process. In some examples, after the mold closing process, there can be a gap between the connecting portion 320 and the mold cavity 40, thereby allowing the connecting portion 320 to be covered by the injection molding material 50.

[0081] In some examples, the support mechanism 22 may be a support point with a small contact area with the flexible film 30. Multiple support mechanisms 22 may be provided within the mold 1. The number of support mechanisms 22 can be determined based on the size and shape of the injection molded object.

[0082] In some examples, the connector 320 may not be injection molded. In some examples, there may be no gap between the connector 320 and the mold cavity 40. This allows the connector 320 to be free from being covered by the injection molding material 50.

[0083] In step S40, as described above, the upper mold 10 and the lower mold 20 can be held, and the upper mold 10 and the lower mold 20 can be heat-treated to solidify the injection molding material 50 (molding process).

[0084] In some examples, the upper mold 10 and the lower mold 20 can be kept in the closed state (see [reference]). Figure 2The upper mold 10 and the lower mold 20 are placed in a heat treatment device (not shown) to perform heat treatment, so that the injection material 50 is solidified and formed. In some examples, the heat treatment device is not particularly required, and can be a conventional oven or a specially designed heat treatment device. In some examples, the upper mold 10 and the lower mold 20 in the clamped state can be directly subjected to heat treatment without being placed in the heat treatment device, for example, by heating the mold 1 by moving a heat source. Thus, the different heat treatment requirements under different process conditions can be met.

[0085] In some examples, the heat treatment can be selected from one or a combination of cooling, heat preservation, and heating. In this case, different heat treatment methods can be used to solidify and form the injection material with different properties, so that the injection material with different properties can be better solidified and formed. In some examples, for thermosetting injection material, it can be solidified and formed by heating. In other examples, for thermoplastic injection material, it can be solidified and formed by cooling.

[0086] In some examples, in the forming process (step S40), the temperature for solidification and formation can be 110-150°C. Thus, the optimal forming time and rate can be controlled, and the flexible film 30 can be better injection molded.

[0087] In some examples, the shape of the flexible film 30 after injection molding can match the shape of the mold cavity 40, for example, the shape of the flexible film 30 after injection molding can be the same as the mold cavity 40. Thus, after the forming process, the flexible film 30 can be formed into a specific shape. In some examples, the flexible film 30 is formed into a flexible film with a specified curvature, wherein the lower surface 30b of the flexible film is covered with an injection material such as silicone, and the upper surface 30a of the flexible film 30 or the portion in contact with the boss 12 is not covered with an injection material such as silicone.

[0088] Although the present disclosure has been specifically described above with reference to the drawings and embodiments, it should be understood that the above description is not intended to limit the present disclosure in any form. Those skilled in the art can modify and change the present disclosure as needed without departing from the spirit and scope of the present disclosure, and such modifications and changes are all within the scope of the present disclosure.​

Claims

1. An injection molding method for injection molding a flexible film having a stimulating electrode, characterized by: The injection molding method comprises: preparing a mold and the flexible film, the mold comprising an upper mold having a first recess, and a lower mold cooperating with the upper mold and having a second recess for configuring the flexible film, the flexible film having an upper surface and a lower surface, the upper surface facing the upper mold, the lower surface facing the lower mold, the stimulating electrode being disposed on the upper surface, configuring the flexible film in the lower mold, the first recess being provided with a protruding platform protruding from the bottom of the first recess, the lower mold being provided with an injection port for providing injection material and communicating with the second recess, the flexible film covering the injection port; clamping the upper mold and the lower mold to form a mold cavity, the gap between the protruding platform and the lower mold being greater than the thickness of the flexible film, the edge of the flexible film having a gap with the mold cavity; using injection material with a density greater than that of the flexible film, injecting the injection material into the mold cavity through the injection port, making the flexible film float under the buoyancy of the injection material, and making the surface of the flexible film fit the edge of the protruding platform; and, making the injection material solidify and form.

2. The injection molding method of claim 1, wherein: The size of the flexible film matches the size of the second recess.

3. The injection molding method of claim 1, wherein: The buoyancy of the injection material is adjusted within a preset range by controlling the injection rate of the injection material.

4. The injection molding method of claim 1, wherein: The upper surface of the flexible film is made to fit the protruding platform before the injection material by filling the mold cavity with the injection material, and the stimulating electrode on the upper surface of the flexible film is covered by the protruding platform without being covered by the injection material.

5. The injection molding method of claim 1, wherein: The flexible film is composed of at least one selected from polyimide, polydimethylsiloxane and polychlorinated p-xylene.

6. The injection molding method of claim 1, wherein: The upper mold and the lower mold are heat treated to solidify and form the injection material.

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