Injection molding apparatus

Abstract

The present disclosure relates to an injection molding device, which includes an upper mold having a first recess, and a lower mold cooperating with the upper mold and having a second recess for configuring a film to be injection molded, a ledge being provided at a bottom of the first recess, an injection port for injecting an injection material being provided at a bottom of the second recess, the upper mold and the lower mold being closed to form a mold cavity, a gap between the ledge and the lower mold being greater than a thickness of the film to be injection molded, and an edge of the film to be injection molded having a gap from the mold cavity. According to the present disclosure, an injection molding device that facilitates positioning of a film to be injection molded in a mold and molding of the film to have a specific shape can be provided.

Description

[0001] This application is a divisional application of the patent application filed on August 27, 2019, with application number CN201910793899.X and invention title: Injection Molding Method of Flexible Thin Film with Stimulating Electrode. Technical Field

[0002] This disclosure relates to an injection molding apparatus. Background Technology

[0003] In the field of medical devices, many sensing or structural components require silicone injection molding to meet biocompatibility requirements. For example, implantable medical devices often include stimulation components with stimulating electrodes. The stimulating electrode area needs to stimulate the implantation site and therefore needs to be exposed. Moreover, the stimulation component is injection molded into a specific shape according to the usage environment.

[0004] In existing injection molding processes for stimulation components, a pre-prepared stimulation component with stimulation electrodes is placed into a mold, and then liquid silicone material is injected. The liquid silicone binds to and solidifies with the stimulation component, thereby being injection molded into a product with a specific shape. To form the stimulation component into a specific shape, the stimulation electrode area usually needs to be pre-bonded to or adsorbed onto the inner surface of the mold cavity to avoid being covered by the liquid silicone, while simultaneously forming the specific shape after solidification.

[0005] However, in the aforementioned prior art, if the stimulation electrode area is pre-bonded to the inner surface of the mold, an adhesive needs to be applied to the surface of the stimulation electrode. After the insert is molded, it needs to be separated from the mold, which can easily lead to tearing or detachment of the stimulation electrode, thus affecting its performance. Using adsorption to fix the stimulation electrode area presents challenges in setting the size of the adsorption holes and controlling the vacuum adsorption force. Summary of the Invention

[0006] This disclosure was made in view of the above-mentioned state of the prior art, and its purpose is to provide an injection molding method for a flexible thin film with stimulating electrodes that can be easily positioned and formed into a specific shape.

[0007] To this end, this disclosure provides an injection molding method for a flexible film with stimulating electrodes, comprising: a configuration step, preparing an upper mold having a first groove and a lower mold cooperating with the upper mold, configuring the flexible film with stimulating electrodes in the lower mold, wherein a protrusion with a predetermined curvature protruding from the bottom of the first groove is provided in the first groove, and an injection port for providing injection molding material is provided in the lower mold; a mold closing step, closing the upper mold and the lower mold to form a mold cavity; a positioning step, injecting injection molding material into the mold cavity through the injection port, causing the flexible film to float and adhere to the protrusion; and a molding step, holding the upper mold and the lower mold, and heat-treating the upper mold and the lower mold to solidify the injection molding material.

[0008] In this disclosure, a flexible film is placed in a mold cavity formed by an upper mold and a lower mold, and injection molding material is injected into the mold cavity. In this case, the flexible film can float under the buoyancy of the injection molding material and adhere to the protrusion. Then, the upper mold and the lower mold are held together and subjected to heat treatment. This allows the injection molding material to cover the remaining portions of the flexible film that are not adhered to the protrusion.

[0009] In the injection molding method provided in this disclosure, optionally, during the positioning process, the flexible film is tightly adhered to the protrusion by filling the mold cavity with the injection molding material. In this case, the portion of the flexible film adhering to the protrusion is not covered by the injection molding material, while the other portions of the flexible film are fully covered by the injection molding material.

[0010] In the injection molding method provided in this disclosure, optionally, the flexible film includes a stimulation portion having a stimulation electrode and a connecting portion electrically connected to the stimulation portion. In the positioning step, the stimulation portion of the flexible film is made to float and conform to the protrusion. In this case, the stimulation portion with the stimulation electrode can be connected to the connecting portion, and the stimulation portion can be coated with injection molding material.

[0011] In the injection molding method provided in this disclosure, optionally, during the mold closing process, the gap between the protrusion and the lower mold is greater than the thickness of the flexible film. This allows the flexible film to be better covered.

[0012] In the injection molding method provided in this disclosure, optionally, the flexible film has functional and non-functional areas including stimulation electrodes, and in the positioning process, the functional areas are covered by the protrusions. In this case, the functional areas of the flexible film are not covered by the injection molding material, thereby enabling the functional areas of the flexible film to better perform their functions.

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

[0014] In the injection molding method provided in this disclosure, optionally, during the molding process, the flexible film is molded into a curved surface having the specified curvature. This allows the flexible film to be better adapted to different process requirements.

[0015] In the injection molding method provided in this disclosure, optionally, the lower mold is provided with a plurality of injection ports, and the flexible film covers the plurality of injection ports. In this case, the injection molding material can enter the mold cavity from the lower mold, thereby allowing the flexible film to float under the buoyancy of the injection molding material.

[0016] In the injection molding method provided in this disclosure, optionally, a second groove for configuring the flexible film is provided in the lower mold. This allows the flexible film to be configured in the lower mold.

[0017] In the injection molding method provided in this disclosure, optionally, the bottom of the second groove is a protrusion with the specified curvature. In this case, the flexible film can be cured and molded into different shapes, thereby enabling the flexible film to be better suited to different process requirements.

[0018] According to this disclosure, an injection molding method can be provided for a flexible thin film with stimulating electrodes that can be easily positioned and formed into a specific shape. Attached Figure Description

[0019] Figure 1 This is a schematic flowchart illustrating the injection molding method according to the embodiments of this disclosure.

[0020] Figure 2 This is a schematic diagram showing the structure of the mold after mold closing according to the embodiments of this disclosure.

[0021] Figure 3 This is a schematic diagram showing the structure of the separated mold according to an embodiment of the present disclosure.

[0022] Figure 4 It shows Figure 3 A partial schematic diagram of the second groove shown.

[0023] Figure 5 This is a schematic diagram illustrating the application of the injection molding method according to the embodiments of this disclosure.

[0024] Figure 6 yes Figure 5 A partial schematic diagram of the mold cavity is shown.

[0025] 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.

[0026] Figure 8 This is a cross-sectional schematic diagram of a mold when the flexible film according to an embodiment of the present disclosure is positioned on a protrusion.

[0027] Explanation of symbols in the attached drawings:

[0028] 1. Mold; 10. Upper mold; 10a. First mating surface; 11. First groove; 11a. Bottom; 12. Protrusion; 20. Lower mold; 20a. Second mating surface; 21. Second groove; 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. Upper surface; 310. Stimulation part; 311. Functional area; 320. Connecting part; 321. Through hole; 40. Mold cavity. Detailed Implementation

[0029] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same components, and repeated descriptions are omitted. Furthermore, the drawings are merely schematic diagrams, and the proportions of the components or the shapes of the components may differ from actual figures.

[0030] Furthermore, the subheadings and similar terms used in the following description of this disclosure are not intended to limit the content or scope of this disclosure; they are merely intended to serve as reading prompts. Such subheadings should not be construed as dividing the content of the article, nor should the content under a subheading be limited to the scope of that subheading.

[0031] The injection molding method disclosed herein is a method for injection molding a flexible film with stimulating electrodes (hereinafter also referred to as the "injection molding method"). In the injection molding method disclosed herein, a flexible film with stimulating electrodes is disposed in a mold, and injection molding material is injected into the mold so that the flexible film floats in the mold under the buoyancy of the injection molding material and adheres to the mold to form a shape with a predetermined curvature. The mold is then heat-treated to injection mold the flexible film. The specific embodiments of this disclosure are described in detail below with reference to the accompanying drawings.

[0032] In this disclosure, the flexible film can be used in the field of medical devices, for example, in retinal electrical stimulators, which may include an implantable portion and an external portion. The flexible film can be used in the implantable portion of the retinal electrical stimulator. The flexible film can be a flexible film with stimulating electrodes, through which the retina can be stimulated. Therefore, the flexible film needs to be injection molded to meet biocompatibility requirements. The flexible film can be molded into a specific shape, and the stimulating electrodes on the flexible film are not covered.

[0033] The injection molding method disclosed herein is particularly suitable for injection molded objects with flexibility, such as flexible films. The injection molded object is formed by placing it in a mold and injecting molding material into the mold, causing the object to float in the mold under the buoyancy of the molding material and adhere to the mold to form a shape with a specified curvature. The mold is then heat-treated to perform the injection molding process.

[0034] Figure 1 This is a schematic flowchart illustrating the injection molding method according to the embodiments of this disclosure.

[0035] In this embodiment, such as Figure 1 As shown, the injection molding method may include the following steps: a configuration step, preparing an upper mold 10 having a first groove 11 and a lower mold 20 cooperating with the upper mold 10, configuring a flexible film 30 having a stimulation electrode in the lower mold 20, wherein a protrusion 12 protruding from the bottom 11a of the first groove 11 and having a predetermined curvature is provided in 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 step, closing the upper mold 10 and the lower mold 20 to form a mold cavity 40 (step S20); a positioning step, injecting injection molding material into the mold cavity 40 through the injection port, causing the flexible film 30 to float and adhere to the protrusion 12 (step S30); and a molding step, holding the upper mold 10 and the lower mold 20, and heat-treating the upper mold 10 and the lower mold 20 to solidify and shape the injection molding material (step S40).

[0036] In step S10, as described above, an upper mold 10 having a first groove 11 and a lower mold 20 cooperating with the upper mold 10 can be prepared. A flexible film 30 having a stimulation electrode can be disposed in the lower mold 20. A protrusion 12 with a predetermined curvature protruding from the bottom 11a of the first groove 11 is provided in the first groove 11 (see [link to relevant documentation]). Figure 3 The lower mold 20 is provided with injection ports for providing injection molding material (in this embodiment, injection ports 111 and 112, see [reference]). Figure 7 ).

[0037] Figure 2This is a schematic diagram showing the structure of the mold after mold closing according to the embodiments of this disclosure. Figure 3 This is a schematic diagram showing the structure of the separated mold according to an embodiment of the present disclosure. Figure 4 It shows Figure 3 A partial schematic diagram of the second groove shown.

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

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

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

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

[0042] In some examples, such as Figure 3 As shown, a first groove 11 may be formed on the first mating 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 may be a plane or a curved surface, etc.

[0043] In some examples, the flexible film 30 may have an upper surface 30a and a lower surface 30b. The upper surface 30a may face the upper mold 10, and the lower surface 30b may face the lower mold 20. In some examples, the stimulation electrode as described above may be disposed on the upper surface 30a of the flexible film 30, forming a functional area 311 (e.g., a stimulation electrode region) on the upper surface 30a. In some examples, the protrusion 12 may not be provided in the first groove 11; in this case, the stimulation electrode region may 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 positioning process described above, 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 Figures 5 to 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 may be provided with an injection port. In some examples, the molding material can be injected into the lower mold 20 (e.g., the second groove 21) through the injection port. For example, as Figure 7 As shown, injection ports (e.g., injection ports 111 and 112) may be provided at the bottom 21a of the second groove 21.

[0055] In step S20, as described above, the upper mold 10 and the lower mold 20 can be closed to form a mold cavity 40. In some examples, the mold cavity 40 may include a cavity portion 41 and an extension portion 42 communicating with the cavity portion 41. In this case, the cavity portion 41 and the extension portion 42 together form the mold cavity 40 of the mold 1. In addition, in some examples, the aforementioned protrusion 12 may be formed in the cavity portion 41.

[0056] In some examples, such as Figures 5 to 7 As shown, in step S20, the flexible film 30 can be placed in the lower mold 20, and the upper mold 10 and the lower mold 20 can be aligned along... Figure 5 The mold closes in the direction indicated by arrow A, forming the mold cavity 40. In some examples, the mold cavity 40 is sealed except for its connection to the injection port, in which case the injection material injected into the mold cavity 40 will not flow out of the mold cavity 40.

[0057] As described above, after the upper mold 10 and the lower mold 20 are assembled to form mold 1, the first groove 11 and the second groove 21 can be combined to form mold cavity 40. In some examples, the shape and size of mold cavity 40 can be determined by the shape and size of the first groove 11 and the second groove 21. In some examples, the injection molding material can cover the edge of flexible film 30. For example, the edge of flexible film 30 can have a gap with mold cavity 40. In some examples, the gap between protrusion 12 and lower mold 20 can be greater than the thickness of flexible film 30. In this case, the flexible film 30 can be better covered by injection molding material when protrusion 12 is present. In this case, during the injection of injection molding material into flexible film 30, the injection material covers not only the lower surface 30b of flexible film 30 but also the edge of upper surface 30a, thereby covering the edge of flexible film 30 with injection molding material.

[0058] In some examples, when a flexible film 30, including a stimulation portion 310 with stimulation electrodes and a connecting portion 320 connected to the stimulation portion 310, is placed in the mold cavity 40 of the mold 1, the stimulation portion 310 may be arranged in the cavity portion 41, while the connecting portion 320 may be arranged in the extension portion 42. During injection molding of the flexible film 30 in the mold cavity 40, the connecting portion 320 of the flexible film 30 is supported and fixed (described later) by support mechanisms 22 (e.g., multiple) respectively provided in the first groove 11 and the second groove 21, while the stimulation portion 310 of the flexible film 30 is adhered to and positioned in the upper mold 10 by the injection molding material, thereby enabling the flexible film 30 to be molded into an injection molded article of a specific shape.

[0059] Figure 8 This is a cross-sectional schematic diagram of a mold when the flexible film according to an embodiment of the present disclosure is positioned on a protrusion.

[0060] In step S30, as described above, the injection molding material 50 can be injected into the mold cavity 40 through the injection port, causing the flexible film 30 to float and adhere to the protrusion 12.

[0061] In some examples, in step S30, injection molding material 50 can be injected into the mold cavity 40 through injection ports (e.g., injection ports 111 and 112) (see...). Figure 7 and Figure 8 Specifically, in some examples, the flexible film 30 can float under the buoyancy of the injection molding material 50 (e.g., liquid silicone) and thus adhere to the mold 1.

[0062] In the positioning process (step S30), the injection molding material 50 can be a material with a density greater than that of the flexible film 30. This allows the flexible film 30 to float better under the buoyancy of the injection molding material 50. In some examples, the injection molding material 50 may contain plastic or liquid silicone. This allows the injection molding material 50 to better cover the surface of the flexible film 30. In some examples, the plastic and liquid silicone used may be biocompatible. In some examples, the plastic may be selected from at least one composition of polylactic acid and polyurethane, thereby enabling the flexible film 30 to be better applied in the field of medical devices.

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

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

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

[0066] In the positioning process (step S30), the injection material 50 can be injected into the mold cavity 40 through the injection hole 110a (for example, it can be injected into the injection hole 110a along the direction of gravity). After the injection material 50 enters the injection hole 110a, it can flow along the injection channel 110. The injection channel 110 can change the flow direction of the injection material 50, so that the injection material 50 (via the sub-channels 110a1 and 110a2) can enter the mold cavity 40 from the injection port (for example, injection port 111 or injection port 112). In this case, due to the force of gravity, the injection material 50 entering the mold cavity 40 is blocked by the flexible film 30 arranged on the injection port 111 or injection port 112 after entering the mold cavity 40 and flows along the lower surface 30b of the flexible film 30, and gradually supports the entire lower surface 30b of the flexible film 30. The flexible film 30 floats under the buoyancy of the injection material 50, and then the upper surface 30a of the flexible film 30 adheres to the mold 1, thereby positioning the flexible film 30 into a specific shape.

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

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

[0069] In some examples, as described above, the bottom 21a of the second groove 21 may be provided with multiple injection ports (e.g., injection port 111 and injection port 112). In some examples, the bottom 21a of the second groove 21 may be provided with multiple injection ports. In some examples, the flexible film 30 disposed in the second groove 21 may cover the aforementioned multiple injection ports (e.g., injection port 111 and injection port 112). In this case, the injection molding material 50 can enter the mold cavity 40 from the lower mold, and the flexible film can float under the buoyancy of the injection molding material 50 and thus adhere to the mold 1.

[0070] In some examples, there may be one or more injection holes 110a. In some examples, injection holes 110a may be located in the upper mold 10 and / or the lower mold 20. In this case, it is easier to adapt to the process requirements of different molding processes, thereby facilitating the subsequent injection of the injection molding material 50 into the mold cavity 40.

[0071] In some examples, the viscosity of the injection molding material 50 can be 10 to 1,000,000 Pascals per second. Preferably, the viscosity of the injection molding material 50 can be 300,000 to 600,000 Pascals per second. In this case, controlling the viscosity of the injection molding material 50 within a certain range can ensure that the injection molding material 50 has sufficient fluidity while effectively suppressing problems such as leakage, thereby optimizing the molding process and making it more conducive to the injection molding of the flexible film 30.

[0072] In some examples, the buoyancy of the injection molding material 50 can be adjusted by controlling the injection rate of the injection molding material 50. In some examples, the buoyancy generated by the injection molding material 50 can be equivalent to the buoyancy generated by 0.8 to 0.9 kPa atmospheric pressure. This allows for adjustment of the buoyancy to facilitate better adhesion of the flexible film 30 to the mold 1.

[0073] In some examples, the injection volume of the molding material 50 can be adjusted according to the size of the mold cavity 40. This allows the process requirements of the flexible film 30 to be met. In some examples, in step S30, the molding material 50 can be made to completely fill the mold cavity 40.

[0074] In some examples, the flexible film 30 may include a functional region 311 (see Figure 5 Non-functional regions. For example, the functional region 311 of the flexible film 30 can be a region with a stimulation electrode (i.e., the stimulation electrode region mentioned above), while the non-functional region can be other regions in the flexible film 30 that do not contain the functional region 311.

[0075] In some examples, the functional area 311 of the flexible film 30 may not be covered by the injection molding material 50, while the non-functional area may be covered by the injection molding material 50. In some examples, the injection molding material 50 can enter the mold cavity 40 through the injection port, and the arrangement of one side of the flexible film 30 with the functional area 311 (e.g., the upper surface 30a of the flexible film) in the mold 1 can be determined by the way the injection molding material 50 enters the mold cavity 40. For example, the injection molding material 50 can enter the mold cavity 40 from the bottom 21a of the second groove 21, so that one side of the flexible film 30 with the functional area 311 faces the bottom 11a of the first groove 11. In this case, when the injection molding material 50 enters the mold cavity 40, the flexible film 30 floats up and adheres to the mold 1 (e.g., the bottom 11a or protrusion 12 of the first groove 11) under the action of the injection molding material 50. This allows the functional area 311 of the flexible film 30 to remain uncovered by the injection molding material 50.

[0076] In some examples, one side of the flexible film 30 having the functional area 311 may also have a non-functional area that can be covered by the injection molding material. In some examples, the bottom 11a of the first groove 11 may be provided with a protrusion 12 that matches the functional area 311. In some examples, when the flexible film 30 floats up and adheres to the mold 1 under the action of the injection molding material 50, the functional area 311 may be covered by the protrusion 12. In this case, the functional area 311 of the flexible film 30 can be left uncovered by the injection molding material. In some examples, the functional area 311 may completely overlap with the surface of the protrusion 12, that is, the edge of the protrusion 12 may adhere to the surface of the flexible film 30 surrounding the functional area 311. In some examples, there may 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 be left uncovered by the injection molding material 50, and the non-functional area can be covered by the injection molding 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 molding material 50 when the protrusion 12 is present.

[0078] In some examples, the flexible film 30 floats up and adheres to the mold 1 under the action of the injection molding material 50, and a gap may exist between the flexible film 30 and the bottom 21a of the second groove 21. This allows the non-functional areas of the flexible film 30 to be covered by the injection molding material.

[0079] In some examples, such as Figures 5 to 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 Figures 5 to 7 As shown, after the mold closing process, the connecting part 320 can be fixed in the mold cavity 40. For example, as Figures 3 to 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 lower mold 20 are then placed in a heat treatment apparatus (not shown) for heat treatment to solidify the injection molding material 50. In some examples, the heat treatment apparatus is not particularly required and can be a conventional oven or a specially designed heat treatment apparatus. In some examples, the upper mold 10 and lower mold 20, which are in a closed state, can be heat-treated directly without being placed in a heat treatment apparatus, for example, by heating the mold 1 with a moving heat source. This allows for the satisfaction of different heat treatment requirements under different process conditions.

[0085] In some examples, heat treatment can be selected from cooling, holding, heating, or a combination thereof. In this case, different heat treatment methods can be used to cure and shape injection molding materials with different properties, thereby enabling better curing and shaping of these materials. In some examples, for thermosetting injection molding materials, curing can be achieved by heating. In other examples, for thermoplastic injection molding materials, curing can be achieved by cooling.

[0086] In some examples, the curing temperature in the molding process (step S40) can be 110–150°C. This allows for optimal control of the molding time and rate, enabling better injection molding of the flexible film 30.

[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 that of the mold cavity 40. Thus, after the molding process, the flexible film 30 can be formed into a specific shape. In some examples, the flexible film 30 is molded into a flexible film with a specified curvature, wherein the lower surface 30b of the flexible film is covered with an injection molding material such as silicone, while the upper surface 30a of the flexible film 30, or the portion that adheres to the protrusion 12, is not covered with the injection molding material such as silicone.

[0088] While the present disclosure has been specifically described above in conjunction with the accompanying drawings and embodiments, it is to be understood that the above description does not limit the present disclosure in any way. Those skilled in the art can make modifications and variations to the present disclosure as needed without departing from its essential spirit and scope, and all such modifications and variations fall within the scope of the present disclosure.

Claims

1. An injection molding method, characterized in that: Prepare an upper mold having a first groove and a lower mold that cooperates with the upper mold and has a second groove for configuring a film to be injected, wherein a protrusion protruding from the bottom of the first groove is provided in the first groove, and an injection port for injecting injection material is provided in the lower mold, the injection port being located at the bottom of the second groove; The upper mold and the lower mold are closed to form a mold cavity. The gap between the protrusion and the lower mold is greater than the thickness of the film to be injected. The edge of the film to be injected has a gap with the mold cavity. The injection molding material is injected into the mold cavity through the injection port, causing the film to be injection molded to float under the buoyancy of the injection molding material, so that the stimulation electrode disposed on the film to be injection molded can be attached to the protrusion of the upper mold; and The injection molding material is then cured and molded.

2. The injection molding method as described in claim 1, characterized in that: The film to be injection molded is a flexible film.

3. The injection molding method as described in claim 2, characterized in that: The film to be injection molded has an upper surface and a lower surface, the upper surface facing the upper mold and the lower surface facing the lower mold, and the stimulation electrode is disposed on the upper surface.

4. The injection molding method as described in claim 1, characterized in that: The upper surface of the protrusion has a specified curvature and is concave.

5. The injection molding method as described in claim 1, characterized in that: The density of the injection molding raw material is greater than the density of the film to be injection molded.

6. The injection molding method as described in claim 1, characterized in that: The mold cavity is a sealed cavity.

7. The injection molding method as described in claim 3, characterized in that: When the mold cavity is filled with the injection molding material, the upper surface of the film to be injection molded is attached to the protrusion before the injection molding material, and the stimulation electrode located on the upper surface of the film to be injection molded is attached to the protrusion.

8. The injection molding method as described in claim 3, characterized in that: When the mold cavity is filled with the injection molding material, the injection molding material covers the lower surface of the film to be injection molded and the edge of the upper surface of the film to be injection molded.

9. The injection molding method as described in claim 1, characterized in that: After the mold cavity is filled with the injection molding material, the injection molding material is solidified and formed by heat treatment of the upper mold and the lower mold.

10. The injection molding method as described in claim 9, characterized in that: The shape of the injection-molded film matches the shape of the mold cavity.

Images