Novel surface microstructure, molding process therefor and use thereof

Abstract

A surface microstructure, a molding process therefor and a use thereof. The surface microstructure comprises a substrate (11) integrally formed on a light-facing surface of a plastic product; the substrate (11) has a first surface facing away from the light-facing surface (220); the surface microstructure further comprises a microstructure layer integrally formed on the first surface of the substrate (11); the microstructure layer comprises at least one first microstructure area (12); the first microstructure area (12) comprises a plurality of first microstructure units (121) arranged on the substrate (11) according to a first rule; the surface of each first microstructure unit (121) is of a spherical structure protruding in a direction away from the substrate (11). The substrate (11) and the microstructure layer are integrally injection-molded by means of a rapid cooling and rapid heating process, the molded first microstructure units (121) are arranged compactly and densely, thereby effectively achieving diffuse reflection of incident light, and reducing surface reflection.

Description

A new surface microstructure and its forming process and application Technical Field

[0001] The present invention relates to the field of plastic surface diffuse reflection structure and molding technology, in particular to a novel surface microstructure and its molding process and application. Background Art

[0002] A camera uses an optical lens to receive light reflected from the subject, creating an image and recording both the subject's dynamic and static effects. To prevent the optical lens from receiving invalid light and ambient stray light, which could affect the imaging quality, a structure that reflects or absorbs invalid and stray light is typically installed on the light-entry side of the camera. This structure, typically made of plastic and shaped like a trumpet, diffusely reflects light on the light-entry side of the camera module, preventing it from entering the optical lens.

[0003] In order to increase the reflection effect of invalid light and stray light, existing camera modules usually first injection-mold the corresponding plastic structure connected to it, and then use a flocking process to form a flocking layer on the light-facing surface of the plastic structure to absorb or reflect the incident light. However, since the flocking process requires special flocking equipment, it leads to increased production costs. In addition, since the flocking layer is mostly composed of fluff or fibers, after long-term use, it is easy to get dusty or accumulate dust, which may cause dust to enter the optical lens and make it difficult to clean. Secondly, since the fluff and fiber structures are tiny, problems such as fluff shedding may occur during use, affecting the imaging of the optical lens. Therefore, there is an urgent need to provide a new surface microstructure and its corresponding molding process to effectively refract and absorb light.

[0004] Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a new surface microstructure and its forming process and application, so as to solve the problems of high processing cost and low processing efficiency of flocking process in the existing technology and the problem that flocking is easy to shed and get dusty, and to achieve effective refraction and absorption of light.

[0006] To achieve the above-mentioned purpose, a technical solution of the present invention provides a new surface microstructure, including a substrate integrally formed on the light-facing surface of a plastic product, the substrate having a first surface arranged back to the light-facing surface, the new surface microstructure also including at least one first microstructure area integrally formed on the first surface of the substrate, the first microstructure area including a plurality of first microstructure units arranged on the substrate according to a first rule, the surface of the first microstructure unit presenting a spherical structure protruding in a direction away from the substrate.

[0007] To achieve the above object, another technical solution of the present invention provides a new surface microstructure forming process, comprising the following steps:

[0008] Add injection molding materials into the barrel, plasticize and complete metering;

[0009] Closing the mold and preheating the mold cavity surface to a first preset temperature, wherein the first preset temperature is greater than the Tg temperature of the injection molding material;

[0010] Filling the injection molding material in the barrel into the mold cavity to form an injection molded part;

[0011] After filling is completed, switch to the pressure holding state to maintain the pressure of the injection molded part;

[0012] After the pressure holding is completed, the cooling channel is opened to cool the mold and the injection molded part to a second preset temperature;

[0013] Open the mold and eject the injection molded part.

[0014] To achieve the above-mentioned purpose, another technical solution of the present invention provides an application of the new surface microstructure as described above on the inner surface of a plastic product and / or an application of the new surface microstructure prepared by the molding process of the new surface microstructure as described above on the inner surface of a plastic product, so as to realize diffuse reflection and absorption of incident light on the inner surface of the plastic product.

[0015] To achieve the above-mentioned purpose, another technical solution of the present invention provides an application of the plastic product as described above in a camera module and / or an application of a new surface microstructure prepared by the molding process of the new surface microstructure as described above in a camera module to reflect and absorb light that is not vertically incident on the camera module.

[0016] The substrate and microstructure layer of the present invention are injection molded by an injection mold and a rapid cooling and heating process is adopted to obtain a first microstructure area and / or a second microstructure area. Before the injection molding raw material is filled, the mold and its cavity surface are preheated to a first preset temperature greater than the Tg temperature of the injection molding raw material, and the mold and the cavity surface are continuously heated at the first preset temperature during the filling process of the injection molding raw material, so that the plastic raw material can fully fill the cavity after entering the cavity, thereby increasing the fullness and height of the first microstructure unit and the second microstructure unit after molding, and each first microstructure unit and each second microstructure unit can be tightly arranged to achieve diffuse reflection of the incident light on the surface of the microstructure unit, reduce invalid light and stray light entering the optical lens, solve the problem of severe reflection caused by concentrated reflection of the light beam, and thus improve the imaging quality of the camera module. At the same time, by forming a first microstructure molding area and a second microstructure molding area on the inner wall of the cavity of the injection mold, which can correspond to the molding of the first microstructure area and the second microstructure area, the substrate and each microstructure unit can be integrally molded through a one-time injection molding process. The molding process only requires one set of molds, which is conducive to saving process costs and improving molding efficiency.

[0017] In addition, a laser process is used to form a microstructure molding area on the inner wall of the mold cavity, so that the microstructure can be molded into one piece with the main body of the plastic product in one process. The structure is stable, the surface is not easy to accumulate dust, and it is easy to clean. There is no need to consider equipment compatibility issues, and the molding efficiency is high and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a schematic structural diagram of a novel surface microstructure according to an embodiment of the present invention.

[0019] FIG2 is a top view of FIG1 .

[0020] FIG3 is a partial enlarged view of the first microstructure region and the second microstructure region.

[0021] FIG4 is a top view of FIG3 .

[0022] FIG5 is a front view of FIG3 .

[0023] FIG6 is a flow chart of a forming process of a novel surface microstructure according to another embodiment of the present invention.

[0024] Figure 7 is a comparison of the temperature change curve of the mold during the new surface forming process and the temperature change curve of the traditional process.

[0025] FIG8 is a graph showing the surface radius measured by scanning the bottom surface profile of the novel surface microstructure using a white light interferometer.

[0026] FIG9 shows the pit size measured by scanning the bottom surface profile of the novel surface microstructure using a white light interferometer.

[0027] FIG10 is a pit roughness curve measured by scanning the bottom surface profile of the novel surface microstructure using a white light interferometer.

[0028] FIG11 is a microstructural morphology diagram of the novel surface microstructure magnified 5 to 50 times by a metallographic microscope.

[0029] FIG12 is a structural dimension diagram of the novel surface microstructure of the present invention measured using an image measuring instrument with a repeatability of 0.1 μm.

[0030] FIG13 is a dimensional diagram of a microstructure produced by a conventional process.

[0031] FIG14 is a maximum surface profile curve of the novel surface microstructure obtained using a profiler.

[0032] FIG15 is a schematic structural diagram of a plastic product using the novel surface microstructure of the present invention.

[0033] FIG16 is a schematic diagram showing the modeling and simulation of the diffuse reflection of the novel surface microstructure of the present invention. DETAILED DESCRIPTION

[0034] The following is further described in detail through specific implementation methods:

[0035] Example

[0036] Please refer to Figures 1 and 2, which are a schematic diagram and a top view of the structure of a new surface microstructure of an embodiment of the present invention. The new surface microstructure of this embodiment includes a substrate 11 and a microstructure layer formed on the substrate 11, wherein the substrate 11 has a first surface and a second surface disposed back to back, the microstructure layer is formed on the first surface, and the microstructure layer has a certain degree of roughness to diffusely reflect the light incident on the microstructure layer, thereby reflecting and absorbing invalid light and stray light, and reducing the occurrence of reflection. In this embodiment, the substrate 11 and the microstructure layer are both formed by injection molding of plastic materials (such as PC), and the microstructure layer is integrally molded on the substrate 11, so that the substrate 11 and the microstructure layer can be realized using the same mold in the same process flow, thereby reducing process costs and improving process efficiency.

[0037] In order to improve the roughness of the microstructure layer, the microstructure layer is realized by a rapid cooling and heating process during injection molding. Before the plastic raw material is injected into the cavity, the mold and the cavity surface are preheated to a temperature above the Tg temperature of the plastic raw material, and the mold and the cavity surface are continuously heated at a temperature greater than or equal to the Tg temperature of the plastic raw material during injection, so that the plastic raw material can be fully filled into the cavity under the action of high temperature, ensuring the fullness and height of the microstructure layer after molding, so that the molding size of the microstructure layer meets the design requirements, and can. In this embodiment, when molding the microstructure layer (including the substrate 11), the molding temperature is 130 to 180°C, and preferably 145°C, so that the plastic raw material can fully fill the cavity; the molding power is 8 to 15KW, and preferably 10KW, so that the mold and cavity surface can be quickly heated to the molding temperature in a short time to improve the molding efficiency. In this embodiment, the thickness of the substrate 11 is 1.5-2.5 mm, preferably 2 mm, and the thickness of the microstructure layer is 0.07-0.09 mm, preferably 0.08 mm, so that the microstructure layer has sufficient roughness to achieve diffuse reflection of light.

[0038] Preferably, the microstructure layer as a whole has a concave curved surface structure, which is conducive to focusing light so that when light enters the surface of the microstructure layer, it can be collected by the curved surface and then reflected and absorbed by the first microstructure area 12, thereby increasing the diffuse reflection and absorption effect of light.

[0039] Referring to Figures 3, 4, and 5, the microstructure layer includes at least one first microstructure region 12, which includes a plurality of first microstructure units 121 arranged on the substrate 11 according to a first rule. Each first microstructure unit 121 can act as an independent structure to reflect and absorb light. In this embodiment, the plurality of first microstructure units 121 are distributed in an array. Preferably, the first microstructure units 121 are arranged in a rectangular array into M rows and N columns. The line connecting the geometric centers of the projections of the first microstructure units 121 in each row on the first surface is orthogonal to the line connecting the geometric centers of the projections of the first microstructure units 121 in each column on the first surface (i.e., the first rule). In other words, the geometric centers of the first microstructure units 121 in any row or column coincide with the projections of the geometric centers of the adjacent previous or next row and previous or next column on a vertical plane perpendicular to the first surface, so that diffuse reflection occurs in the first microstructure region 12, reflecting light irradiated on the surface of the first microstructure units 121 in all directions, thereby improving the light reflection effect. It is understandable that in some other embodiments, the first microstructure units 121 may also be arranged in a circular array, a fan-shaped array, or other polygonal arrays to achieve light reflection.

[0040] In this embodiment, the first microstructure unit 121 is generally a spherical structure that protrudes away from the substrate 11. The radius of the projection of the first microstructure unit 121 on the first surface is 75*(1±15%)μm, preferably 75μm. The height of the projection of the first microstructure unit 121 on a plane perpendicular to the first surface is 75*(1±10%)μm, preferably 75μm. In this embodiment, the radius of the first microstructure unit 121 gradually decreases from the contact point with the substrate 11 toward the direction away from the substrate 11. As a result, the first microstructure unit 121 has an overall hemispherical shape, thereby providing the first microstructure unit 121 with a spherical surface, thereby ensuring that light can be absorbed or reflected. In some other embodiments, the radius of the projection of the first microstructure unit 121 on the first surface may be different from the height of its projection on the plane perpendicular to the first surface, so that the first microstructure unit 121 is semi-ellipsoidal as a whole, so as to change the reflection path of light when it is irradiated on the surface of the first microstructure unit 121; in specific implementation, the tolerance between the two can be controlled within ±10%, that is, the height tolerance of the projection of the first microstructure unit 121 on the plane perpendicular to the first surface satisfies R*90%≤H≤R*110% (wherein, R is the radius of the projection of the first microstructure unit 121 on the first surface, and H is the height of the projection of the first microstructure unit 121 on the plane perpendicular to the first surface).

[0041] It is understandable that in some other embodiments, the first microstructure unit 121 may also be other cubic structures protruding away from the first surface, such as a polyhedron structure. Preferably, the first microstructure units 121 in this embodiment have the same structure, that is, they are all hemispherical or hemi-ellipsoidal, and the spacing between the geometric centers of the projections of the first microstructure units 121 in two adjacent rows and / or two adjacent columns on the horizontal plane is 0.14 to 0.18 mm, preferably 0.16 mm; in this way, it can ensure stable reflection of the light irradiated on the first microstructure unit 121, and reduce the difficulty of process and mold opening; of course, without considering the difficulty and cost of process and mold opening, the first microstructure area 12 can also be a mixed structure formed by a combination of hemispherical, hemi-ellipsoidal, other spheres and / or polyhedrons to increase the irregularity of light reflection, thereby increasing the reflectivity of light.

[0042] In this embodiment, the surface roughness Ra of the bottom surface of any one of the first microstructure units 121 in the bottom surface of the first microstructure region 12 is ≥ 0.1 μm, and the peak roughness Rp of the roughness curve can reach a maximum of 0.8 μm (see FIG10 for the roughness curve), so as to diffusely reflect the light incident on the first microstructure region 12, thereby reflecting or absorbing invalid light and stray light, thereby reducing the occurrence of reflection phenomenon.

[0043] As a preferred embodiment of this embodiment, the microstructure layer may further include at least one second microstructure region 13 integrally formed on the substrate 11 and corresponding to the side of the first microstructure region 12. When the first microstructure region 12 and the second microstructure region 13 are simultaneously provided on the substrate 11, the first microstructure region 12 and the second microstructure region 13 are cross-arranged and arranged in an array on the substrate 11. The second microstructure region 13 has a different arrangement from the first microstructure region 12, so that the first microstructure region 12 and the second microstructure region 13 have different roughnesses. When light enters, the light passes through the first microstructure region 12 and the second microstructure region 13 with different structures, and can present irregular reflection when entering the first microstructure region 12 and the second microstructure region 13, thereby increasing the number of light reflections and improving the reflectivity of the light.

[0044] In this embodiment, a plurality of first microstructure regions 12 and a plurality of second microstructure regions 13 are formed on the substrate 11, and the plurality of first microstructure regions 12 and the plurality of second microstructure regions 13 are distributed in an array on the substrate 11, so that light can be reflected in different directions on the first microstructure regions 12 and the second microstructure regions 13, thereby increasing the number of light reflections and enhancing the microstructure layer's ability to attenuate and reflect light. Preferably, the first microstructure regions 12 and the second microstructure regions 13 can also be arranged in a manner such that the first structure regions 12 and the second microstructure regions 13 intersect to further increase the irregularity of light reflection. It is understandable that in some other embodiments, the cavity positions corresponding to the first microstructure region 12 and the second microstructure region 13 can be adjusted according to needs during the mold design stage, so that the first microstructure region 12 and the second microstructure region 13 are arranged on the substrate 11 according to corresponding positions and rules, such as in a circular array, horizontal cross, vertical cross, etc.; or in some embodiments, only the first microstructure region 12 or only the second microstructure region 13 can be set to achieve multiple reflections of light.

[0045] The second microstructure region 13 includes a plurality of second microstructure units 131 arranged on the substrate 11 according to a second rule, and each second microstructure unit 131 acts as an independent structure to reflect light. In this embodiment, the plurality of second microstructure units 131 are arranged in m rows, and in two adjacent rows of second microstructure units 131, the angle between the line connecting the geometric centers of the projections of the second microstructure units 131 in each row on the horizontal plane and the line connecting the geometric centers of the projections of the second microstructure units 131 in each column on the horizontal plane is less than 90° (i.e., the second rule), that is, in any two adjacent rows of second microstructure units 131, the projection of the geometric center of any second microstructure unit 131 in the latter row on the vertical plane perpendicular to the horizontal plane is located at the adjacent position of the previous row. The projections of the geometric centers of the second microstructure units 131 on the vertical plane overlap, preferably, the angle is 45 degrees, and the projections of the geometric centers of any second microstructure unit 131 in the latter row on the vertical plane perpendicular to the horizontal plane coincide with the midpoint of the projections of the geometric centers of the second microstructure units 131 at adjacent positions in the previous row on the vertical plane. This allows diffuse reflection to occur in the second microstructure area 13, reflecting the light irradiated on the surface of the second microstructure unit 131 in all directions, thereby improving the reflection effect of the light. It is understandable that in some other embodiments, the second microstructure units 131 can also be arranged in a rectangular array, circular array, fan array or other polygonal array like the first microstructure units 121 to achieve light reflection; similarly, the first microstructure units 121 can also be arranged in a staggered arrangement of adjacent rows like the second microstructure units 131.

[0046] In this embodiment, the second microstructure unit 131 is generally a spherical structure that protrudes away from the substrate 11. The radius of the projection of the second microstructure unit 131 on the first surface is 75*(1±15%)μm, and preferably 75μm. The height of the projection of the second microstructure unit 131 on a plane perpendicular to the first surface is 75*(1±10%)μm, and preferably 75μm. In this embodiment, the radius of the second microstructure unit 131 gradually decreases from the contact position with the substrate 11 toward the direction away from the substrate 11. In this way, the second microstructure unit 131 has an overall hemispherical shape, and thus the second microstructure unit 131 has a spherical surface, thereby ensuring that light can be absorbed or reflected. In some other embodiments, the radius of the projection of the second microstructure unit 131 on the first surface may be different from the height of its projection on the plane perpendicular to the first surface, so that the second microstructure unit 131 is semi-ellipsoidal as a whole, so as to change the reflection path of light when it is irradiated on the surface of the second microstructure unit 131; in specific implementation, the tolerance between the two can be controlled within ±10%, that is, the height of the projection of the second microstructure unit 131 on the plane perpendicular to the first surface satisfies R'*90%≤H'≤R'*110% (wherein, R' is the radius of the projection of the second microstructure unit 131 on the first surface, and H' is the height of the projection of the second microstructure unit 131 on the plane perpendicular to the first surface).

[0047] It is understandable that in some other embodiments, the second microstructure unit 131 may also be other cubic structures formed by protruding away from the first surface, such as a polyhedron structure.

[0048] Preferably, the second microstructure units 131 in this embodiment have the same structure, that is, they are all hemispherical or hemispherical, and the spacing between the geometric centers of the projections of two adjacent rows and / or two adjacent columns of the second microstructure units 131 on the horizontal plane is 0.14 to 0.18 mm, preferably 0.16 mm; in this way, it can not only ensure stable reflection of the light irradiated on the second microstructure units 131, but also reduce the difficulty of process and mold opening; similarly, without considering the difficulty and cost of process and mold opening, the second microstructure area 13 can also be a mixed structure formed by a combination of hemispherical, hemispherical, other spheres and / or polyhedrons to increase the irregularity of light reflection, thereby increasing the reflectivity of light.

[0049] In this embodiment, the surface roughness Ra of the bottom surface of any second microstructure unit 131 in the bottom surface of the second microstructure region 13 is ≥ 0.1 μm, and the peak roughness Rp of the roughness curve can reach a maximum of 0.8 μm (see Figure 10 for the roughness curve), so as to diffusely reflect the light incident on the second microstructure region 13, and then reflect or absorb invalid light and stray light, thereby reducing the occurrence of reflection phenomenon.

[0050] It is understandable that in other embodiments, the first microstructure region 12 and the second microstructure region 13 can also be formed by a plurality of first microstructure grooves and a plurality of second microstructure grooves formed by depressions in accordance with the above-mentioned rectangular array, circular array, fan-shaped array, other polygonal arrays and / or staggered arrangement, so as to reflect the irradiated light through the inner walls of the first microstructure grooves and the second microstructure grooves.

[0051] In this embodiment, the area of ​​each first microstructure region 12 and / or second microstructure region 13 is 20 to 30 cm2, and the shapes of the first microstructure region 12 and the second microstructure region 13 are preferably in the positive direction. Preferably, the side length of the first microstructure region 12 and the second microstructure region 13 is 5 mm, that is, the corresponding area of ​​the first microstructure region 12 and the second microstructure region 13 is 25 cm2. It is understandable that in other embodiments, the first microstructure region 12 and the second microstructure region 13 can also be arranged adjacent to each other and the first microstructure region 12 and the second microstructure region 13 can also be arranged in other shapes, such as a cuboid, a circle, a sector, a triangle, and other polygons.

[0052] Preferably, in order to mold the first microstructure region 12 and the second microstructure region 13, the injection mold is designed and processed according to the specific structure, size and arrangement of the novel surface microstructure, so as to form a cavity having a novel surface microstructure molding region in the injection mold. In this embodiment, the cavity of the injection mold has a first molding surface corresponding to the inner surface of the molded new surface microstructure (i.e., one side surface of the microstructure layer) and a second molding surface corresponding to the outer surface of the molded new surface microstructure (i.e., one side surface of the substrate 11). The first molding surface is formed with a first microstructure molding area corresponding to the first microstructure area 12 and / or a second microstructure molding area corresponding to the second microstructure area 13 by a laser process. The first microstructure molding area has a first microstructure molding groove corresponding to the first microstructure unit 121, and the second microstructure molding area has a second microstructure molding groove corresponding to the second microstructure unit 131, so that when the plastic raw material is injected, based on the injection mold and cavity temperature preheated to the molding temperature, the plastic raw material is fully filled into the first microstructure molding groove of the first microstructure molding area and the second microstructure molding groove of the second microstructure molding area to correspondingly mold the first microstructure area 12 and / or the second microstructure area 13.

[0053] The surface microstructure of this embodiment forms the first microstructure unit 121 and / or the second microstructure unit 131 on the substrate 11 by adopting a rapid cooling and heating process, so that the plastic raw material can fully fill the cavity after entering the cavity, thereby increasing the fullness of the first microstructure unit 121 and the second microstructure unit 131 after molding, so as to achieve multiple reflections of the light incident on the first microstructure unit 121 and the second microstructure unit 131, improve the reflection effect of the light, and reduce invalid light and stray light; at the same time, the first microstructure unit 121 and the second microstructure unit 131 are integrally injection molded with the substrate 11 using plastic raw material, and the surface of the formed microstructure layer is not easy to be stained or accumulated with dust, is easy to clean, and can still remain clean and clear after long-term use, and has high light reflection efficiency.

[0054] As another preferred embodiment of the present invention, the present invention provides a molding process for a novel surface microstructure. The molding process for the novel surface microstructure of this embodiment is used to integrally mold the novel surface microstructure on the light-facing surface of the plastic product (especially the trumpet-shaped plastic product for the light-incident side of the camera module) to obtain a microstructure with a full structure and meeting the design size, and then diffusely reflect the incident light to reduce the reflection effect and avoid invalid light and stray light from entering the camera module. It is understandable that although this embodiment is mainly described with reference to the molding of microstructures on trumpet-shaped plastic products, this embodiment is not limited to this, and can also be used for the processing of other plastic products and even metal products that require molding microstructures to obtain microstructures with a full structure and meeting the design size.

[0055] In a specific implementation, a mold is designed and processed based on the specific structure, size, and arrangement of the novel surface microstructure, so as to form a cavity having a novel surface microstructure forming region within the mold. In this embodiment, the mold cavity has a first forming surface corresponding to the inner surface (i.e., the microstructure layer) of the molded novel surface microstructure and a second forming surface corresponding to the outer surface (i.e., the substrate 11) of the molded novel surface microstructure. The first forming surface is formed using a laser process to form a first microstructure forming region corresponding to the first microstructure region 12 and / or a second microstructure forming region corresponding to the second microstructure region 13, so as to form the first microstructure region 12 and / or the second microstructure region 13.

[0056] Please refer to Figure 6, which is a flow chart of a novel surface microstructure forming process provided by the present invention. The novel surface microstructure forming process of this embodiment specifically includes the following steps:

[0057] S1: Set the molding temperature and hot runner temperature and preheat.

[0058] According to the material and hot melt properties of the injection molding raw material, the barrel temperature and hot runner temperature of the mold are set, and the barrel and hot runner are preheated at the set barrel temperature and hot runner temperature. In this embodiment, according to the flow and plasticization process of the injection molding raw material, the barrel is divided into a nozzle section, a fourth heating section, a third heating section, a second heating section, a first heating section, and a discharge port section in sequence; since the injection molding raw material used in the product molded in this embodiment is plastic, the molding temperatures corresponding to the nozzle section, the fourth heating section, the third heating section, the second heating section, the first heating section, and the discharge port section of the barrel are set to 295-315°C, 295-315°C, 290-310°C, 280-300°C, 270-290°C, and 260-280°C, respectively, and the molding temperature of the hot runner is set to 290-330°C, so that the injection molding raw material can be quickly plasticized and flowed in the barrel and the hot runner.

[0059] S2: Plasticize the injection molding materials and complete the metering.

[0060] Specifically, injection molding raw materials are added into the barrel from the discharge port section, the injection molding raw materials entering the barrel are plasticized by a heating component (such as a heating plate, a heating coil, etc.) arranged outside the barrel, and the injection molding raw materials are transferred by a screw in the barrel. During the transfer process, the injection molding raw materials are measured according to the volume of injection molding raw materials required to form a complete product.

[0061] In this embodiment, when measuring the injection molding raw materials, multi-stage measurement is adopted, and the measurement parameters of each stage are switched based on the position. Specifically, a three-stage measurement method is adopted:

[0062] In the first metering stage, the speed of the screw in the barrel is 60*(1±20%)rpm, and the back pressure of the screw is 40*(1±20%)kgf / cm2. After the screw moves backward from its starting position to the first metering position, the speed and back pressure of the screw are controlled to quickly switch to the metering parameters required for the second metering stage; the first metering position is 15±3mm away from the starting position of the screw.

[0063] In the second metering stage, the speed of the screw in the barrel is 60*(1±20%)rpm, and the back pressure of the screw is 40*(1±20%)kgf / cm2. After the screw continues to move backward from the first metering position to the second metering position, the parameters such as the speed and back pressure of the screw are controlled to quickly switch to the metering parameters required for the third metering stage; the second metering position is 50±3mm away from the starting position of the screw.

[0064] The third metering stage is also the metering completion stage. During this stage, the rotation speed of the screw in the barrel is 60*(1±20%)rpm, and the back pressure of the screw is 40*(1±20%)kgf / cm2. The screw continues to move backward from the second metering position to the third metering position (also known as the metering completion position), and then the screw is controlled to loosen; the metering completion position is 58±3mm away from its starting position, the loosening distance is 5±3mm, and the loosening speed is 15*(1±20%)mm / s. After loosening, the screw is 73±3mm away from its starting position, which is also the starting position of the following filling stage.

[0065] In this embodiment, a three-stage metering method is used to effectively increase the accuracy and stability of injection molding material metering, thereby improving molding precision. It is understood that in other embodiments, the screw speed, back pressure, etc. can be adjusted in a timely manner according to the molding precision and molding efficiency requirements to quickly complete metering. Alternatively, a single-stage metering method can be used, where the screw is immediately released after a single movement to improve metering efficiency.

[0066] S3: closing the mold and preheating the mold and cavity surface to a first preset temperature.

[0067] After the front and rear molds are closed, the mold cavity surface is preheated to a first preset temperature. Heating can be provided by a heating plate or heating coil mounted on the mold, or by providing a heating pipeline to heat the mold through fluid flow and heat exchange with the mold. The first preset temperature is greater than the Tg temperature of the injection molding material. In this embodiment, depending on the type of injection molding material, the first preset temperature is preferably 135-145°C, and the heating power is 8-15 kW. This allows the mold to be quickly heated to the first preset temperature in a short period of time, thereby improving molding efficiency.

[0068] In this embodiment, a multi-stage mold clamping method is used to clamp the front and rear molds of the mold. The first mold clamping pressure is used to relatively move to the first mold clamping position, then switch to the second mold clamping pressure, and then relatively move until the mold is closed. The first mold clamping pressure is greater than the second mold clamping pressure, and the mold clamping speed decreases during the relative movement of the front and rear molds of the mold; the first mold clamping pressure is 230*30%*(1±20%)TON. In specific implementation, a five-stage mold clamping method is used:

[0069] In the first mold closing stage, the front mold and the rear mold move relative to each other to the first mold closing position at a second mold closing pressure of 230*(1±20%)TON and a mold closing speed of 40-50%; the first mold closing position is a position where the corresponding surfaces of the front mold and the rear mold are 350±3mm apart.

[0070] In the second mold closing stage, the front mold and the rear mold move relative to each other to the second mold closing position at a second mold closing pressure of 230*(1±20%)TON and a mold closing speed of 35-45%; the second mold closing position is a position where the corresponding surfaces of the front mold and the rear mold are 200±3mm apart.

[0071] In the third mold closing stage, the front mold and the rear mold move relative to each other to the third mold closing position at a second mold closing pressure of 230*(1±20%)TON and a mold closing speed of 25-35%; the third mold closing position is a position where the corresponding surfaces of the front mold and the rear mold are 150±3mm apart.

[0072] In the fourth mold closing stage, the front mold and the rear mold move relative to each other to the fourth mold closing position at a second mold closing pressure of 230*(1±20%)TON and a mold closing speed of 20-30%; the third mold closing position is a position where the corresponding surfaces of the front mold and the rear mold are 80±3mm apart.

[0073] In the fifth end mold closing stage, which is also the final mold locking stage, the front mold and the rear mold move relative to each other at a mold closing speed of 20-30% to the mold locking position; the mold locking position is a position where the corresponding surfaces of the front mold and the rear mold are 3±3mm apart. In this embodiment, in the fifth mold closing stage, in order to avoid the pressure process when the front mold and the rear mold are in contact, this stage is divided into a high-pressure stage and a low-pressure stage during the specific implementation. In the high-pressure stage, the front mold and the rear mold move relative to each other at the second mold closing pressure of 230*(1±20%)TON to the low-pressure switching position, and then immediately move relative to each other at the first mold closing pressure of 230*30%*(1±20%)TON to the mold locking position to increase the mold closing stability of the front mold and the rear mold; the low-pressure switching position is a position where the corresponding surfaces of the front mold and the rear mold are 30±3mm apart.

[0074] In this embodiment, a five-stage mold clamping method is adopted. During the relative movement of the front mold and the rear mold, the mold clamping speed gradually decreases and the mold clamping pressure switches from high pressure to low pressure. That is, when the distance between the front mold and the rear mold is relatively far, the mold is clamped at a higher mold clamping speed and a higher mold clamping pressure, so that the front mold and the rear mold can quickly approach each other. When the distance between the front mold and the rear mold is relatively close, the mold is clamped at a lower mold clamping speed and a lower mold clamping pressure. At this time, the guide pins of the front mold and the rear mold begin to contact. The lower mold clamping speed can reduce the mechanical vibration when the front mold and the rear mold contact, thereby increasing the stability of the mold clamping and reducing the risk of damage caused by collision between the front mold and the rear mold, thereby increasing the service life of the mold. It is understandable that in some other embodiments, the number of mold clamping sections, the mold clamping speed and the pressure of the front mold and the rear mold can also be determined according to the distance and stroke between the front mold and the rear mold to adapt to the injection molding of the corresponding structural product.

[0075] S4: Filling injection molding materials.

[0076] When the mold is preheated to a first preset temperature and the injection molding material in the barrel is metered, the screw is controlled to move so as to fill the injection molding material in the barrel into the mold cavity to form an injection molded part.

[0077] In this embodiment, a staged filling method is used during filling, with a certain filling pressure and filling speed. The filling speed first increases and then decreases to quickly fill the injection molding material into the mold cavity. In specific implementation, a five-stage mold closing method is used, and position is prioritized when switching from the filling stage to the pressure holding stage:

[0078] In the first filling stage, the filling pressure is 2300*(1±20%)kgf / cm2, the filling speed is 20*(1±20%)mm / s, and the screw squeezes the injection molding material from the metering completion position (specifically, the position after the screw is loosened after the metering is completed) to the first filling position; the first filling position is 52±3mm (that is, the distance between the screw and its final position).

[0079] In the second filling stage, the filling pressure is 2300*(1±20%)kgf / cm2, the filling speed is 45*(1±20%)mm / s, and the screw fills the injection molding material from the first filling position to the second filling position; the second filling position is 12±3mm.

[0080] In the third end filling stage, the filling pressure is 2300*(1±20%)kgf / cm2, the filling speed is 25*(1±20%)mm / s, and the screw fills the injection molding material from the second filling position to the pressure holding switching position, wherein the pressure holding switching position is 6±3mm.

[0081] During the filling process, the mold and cavity surface are continuously maintained at the first preset temperature until the filling and even the pressure holding are completed, so that the injection molding material can be fully filled into the cavity, thereby increasing the fullness and height of the microstructure after molding, and then being able to diffusely reflect light through the microstructure, ensuring that the molding size of the new surface microstructure meets the design requirements.

[0082] In this embodiment, a three-stage filling method is adopted and the filling speed is first slow, then fast, and then slow again. During the filling process, the filling speed is filled at a relatively slow speed in the first filling stage, so that the plasticized injection molding material can be filled smoothly to prevent defects such as air marks, material flying, and spirals; and in the second filling stage, it is filled at a relatively fast speed, which is conducive to quickly injecting the injection molding material into the mold cavity and ensuring that it can overcome resistance and ensure that the injection molding material is fully filled, thereby preventing problems such as material shortage; finally, in the third filling stage, the filling speed is reduced again to fill at a relatively slow speed to the pressure holding switching position to avoid glue overflow and the formation of indentations at the mold joint of the front mold and the rear mold. It is understandable that in some other embodiments, the number of filling stages, filling position, and filling speed can also be adaptively adjusted according to parameters such as the volume and resistance of the injection molding material to be filled.

[0083] This embodiment uses position as the highest priority for the switching signal from the filling stage to the pressure holding stage, that is, when the screw moves to the pressure holding switching position, the filling is stopped immediately and the mold is quickly switched to the pressure holding state. In this way, it can ensure that the injection molding raw materials can be fully filled to avoid problems such as material shortage. However, when the position is used as the priority, the mold also has a maximum filling time, which is 3*(1±20%)s. Under the limitation of the maximum filling time, since the mold is in a high temperature and high pressure state, in order to ensure the safety of processing, when the maximum filling time is reached, even if the screw has not moved to the pressure holding switching position, the mold will be controlled to quickly switch to the pressure holding state, thereby ensuring the continuity of the molding process.

[0084] It is understandable that in some other embodiments, time can also be set as the maximum priority, that is, whether the filling time is reached or not is used as the switching signal from the filling stage to the holding stage. Once the time is reached, it will be quickly switched to the holding state, thereby ensuring the efficiency and continuity of the molding process.

[0085] S5: Injection molding pressure maintenance.

[0086] When the injection molding material is filled, it can be quickly switched to the pressure holding state to hold the pressure of the injection molded part in the mold. In this embodiment, when holding the pressure, a segmented pressure holding method is adopted and a certain pressure holding speed and pressure are used to hold the injection molded part for a certain time to control the deformation of the product. During the pressure holding process, a small amount of injection molding material is continuously injected to fill the shrinkage space of the injection molded part during cooling and solidification, thereby ensuring the molding quality of the product. In specific implementation, a two-stage pressure holding method is used for pressure holding:

[0087] In the first holding stage, the holding speed is 25*(1±15%)mm / s, the holding time is 1.3*(1±20%)s, and the holding pressure is 1000*(1±15%)kgf / cm2.

[0088] In the second holding stage, the holding speed is 25*(1±15%)mm / s, the holding time is 2*(1±20%)s, and the holding pressure is 900*(1±15%)kgf / cm2.

[0089] In this embodiment, a two-stage pressure holding method is used to hold the injection molded part in stages. This can extend the holding time and pressure curve, ensuring that the injection molded part does not break or crack. It is understood that in other embodiments, the number of pressure holding stages can also be specifically set according to the structure of the molded product to ensure product molding quality.

[0090] S6: Cooling the mold and the injection molded part to a second preset temperature.

[0091] After the pressure holding is complete, the cooling channel is opened to cool the mold and injection molded part to a second preset temperature to ensure smooth demolding of the product. The cooling channel can cool the mold and injection molded part by circulating a fluid (gas, liquid, etc.). The circulating fluid exchanges heat with the mold and injection molded part to quickly cool the mold and injection molded part. In this embodiment, the cooling time is 30*(1±20%)s, and the second preset temperature is 85-95°C.

[0092] S7: Open the mold and eject the injection molded part.

[0093] After the mold and the injection molded part are cooled to a second preset temperature, the mold is opened to demould the injection molded part, thereby completing the integrated molding of the plastic product and the novel surface microstructure.

[0094] In this embodiment, when opening the mold, a multi-stage mold opening method is used to open the front mold and the rear mold of the mold. When the front mold and the rear mold are opened, they are opened at a certain mold opening speed. The mold opening speed first increases and then decreases to the maximum mold opening position, and then the ejector pin ejects the injection molded part. In specific implementation, a five-stage mold opening method is used:

[0095] In the first mold opening stage, the front mold and the rear mold move relative to each other at a mold opening speed of 15-25% to a first mold opening position; the first mold opening position is a position where the corresponding surfaces of the front mold and the rear mold are 35±3 mm apart.

[0096] In the second mold opening stage, the front mold and the rear mold move relative to each other at a mold opening speed of 30-40% to a second mold opening position; the second mold opening position is a position where the corresponding surfaces of the front mold and the rear mold are 85±3 mm apart.

[0097] In the third mold opening stage, the front mold and the rear mold move relative to each other at a mold opening speed of 35-45% to a third mold opening position; the third mold opening position is a position where the corresponding surfaces of the front mold and the rear mold are 160±3 mm apart.

[0098] In the fourth mold opening stage, the front mold and the rear mold move relative to each other at a mold opening speed of 40-50% to a fourth mold opening position; the fourth mold opening position is a position where the corresponding surfaces of the front mold and the rear mold are 400±3 mm apart.

[0099] In the fifth mold opening stage, also known as the mold opening limit stage, the front mold and the rear mold move relative to each other at a mold opening speed of 20 to 30% to the fifth mold opening position (i.e., the mold opening limit position); the fifth mold opening position is a position where the corresponding surfaces of the front mold and the rear mold are 450±3 mm apart.

[0100] In this embodiment, a five-stage mold opening method is adopted. During the relative movement of the front mold and the rear mold, the mold opening speed first gradually increases and then gradually decreases. That is, at the beginning of the mold opening, in order to avoid deformation of the product caused by the airflow pulling on the front mold and the rear mold when the front mold and the rear mold are quickly separated, the front mold and the rear mold are separated at a relatively low mold opening speed, which can ensure the shape and quality of the product. After the front mold and the rear mold are separated, the front mold and the rear mold are quickly separated at a relatively high mold opening speed to shorten the mold opening time of the front mold and the rear mold. Finally, after the front mold and the rear mold are about to reach the maximum mold opening distance, the mold is opened at a relatively low mold opening speed so that the two are moved to the extreme position to reduce the mechanical vibration of the injection molding machine. It is understandable that in some other embodiments, the number of mold opening sections and the mold opening speed of the front mold and the rear mold can also be determined according to the distance and stroke of the front mold and the rear mold to adapt to the injection molding of the corresponding structural product.

[0101] When the front mold and the rear mold are opened to the limit position, space is provided for the ejector to eject the product. When the ejector ejects the product, it performs at least one ejection action. Taking the ejector performing one ejection action as an example, the ejector first extends to the first ejection position and holds it for a certain time, and then extends again to the second ejection position for a certain time to demold the product.

[0102] The novel surface microstructure molding process of the present invention preheats the mold and its cavity surface to a first preset temperature greater than the Tg temperature of the injection molding raw material before filling with the injection molding raw material, and continues to heat the mold and cavity surface at the first preset temperature during the filling of the injection molding raw material, so that the injection molding raw material can fully fill the cavity to increase the fullness and height of the microstructure after molding. The microstructure can be molded into one piece with the main body of the plastic product in one process. The structural molding is stable, the surface is not easy to accumulate dust and is easy to clean. There is no need to consider equipment compatibility issues, and the molding efficiency is high and the cost is low.

[0103] The present invention will be further described below by taking the process of the specific implementation of this embodiment as an example. In the specific implementation, PC raw material is preferably used for integral injection molding of the plastic product and the microstructure of its inner surface.

[0104] S101: Set the molding temperature and hot runner temperature and preheat.

[0105] The molding temperatures corresponding to the nozzle section, fourth heating section, third heating section, second heating section, first heating section and feed port section of the barrel are set to 305°C, 305°C, 300°C, 290°C, 280°C and 270°C respectively, and the molding temperature of the hot runner is set to 310°C.

[0106] S102: Plasticizing the injection molding raw materials and completing metering.

[0107] The screw speed is set to 60rpm and the back pressure is set to 40kgf / cm2. PC raw material particles are added into the barrel. The first and second metering are respectively performed at the screw positions 15mm and 50mm away from its initial position. After metering is completed at the 58mm position, the screw is retracted 5mm at a retraction speed of 15m / s. At this time, the screw stops at the 73mm position, which is the starting position of the screw movement in the filling stage.

[0108] S103: Closing the mold and preheating the mold and cavity surface to a first preset temperature.

[0109] Clamp the front mold and the back mold:

[0110] In the first mold closing stage, the mold is closed at a second mold closing pressure of 230 TON and a mold closing speed of 45% until the distance between the front mold and the rear mold is 350 mm.

[0111] In the second mold closing stage, the mold is closed at a second mold closing pressure of 230 TON and a mold closing speed of 40% until the distance between the front mold and the rear mold is 200 mm.

[0112] In the third mold closing stage, the mold is closed at a second mold closing pressure of 230 TON and a mold closing speed of 30% until the distance between the front mold and the rear mold is 150 mm.

[0113] In the fourth mold closing stage, the mold is closed at a second mold closing pressure of 230 TON and a mold closing speed of 25% until the distance between the front mold and the rear mold is 80 mm.

[0114] In the fifth end mold closing stage, the mold is first closed with the second mold closing pressure of 230TON and the mold closing speed of 25% until the distance between the front mold and the rear mold is 30mm, and then the mold is closed with the first mold closing pressure of 230*30%TON and the mold closing speed of 25% until the distance between the front mold and the rear mold is 2.4mm to complete the mold closing.

[0115] Then, the mold and cavity are heated to 145°C or above with a heating power of 10KW.

[0116] S104: Filling injection molding materials.

[0117] Fill the PC injection molding material in the barrel into the cavity. When filling:

[0118] In the first filling stage, the filling is carried out from the 73mm position to the 52mm position at a filling pressure of 2300kgf / cm2 and a filling speed of 20mm / s.

[0119] In the second filling stage, the filling is carried out from the 52mm position to the 12mm position at a filling pressure of 2300kgf / cm2 and a filling speed of 45mm / s.

[0120] In the third end filling stage, the filling is carried out from the 12mm position to the 6mm position at a filling pressure of 2300kgf / cm2 and a filling speed of 25mm / s, and then quickly turns to the pressure holding stage.

[0121] S105: Injection molding pressure maintenance.

[0122] Maintaining pressure on injection molded parts:

[0123] In the first holding stage, the holding speed is 25 mm / s, the holding time is 1.3 s, and the holding pressure is 1000 kgf / cm2.

[0124] In the second holding stage, the holding speed is 25 mm / s, the holding time is 2 s, and the holding pressure is 900 kgf / cm2.

[0125] S106: Cooling the mold and the injection molded part to a second preset temperature.

[0126] After the pressure holding is completed, the mold and the injection molded part are cooled to below 90°C.

[0127] S107: Open the mold and eject the injection molded part.

[0128] Open the front mold and the back mold of the mold:

[0129] In the first mold opening stage, the mold is opened at a mold opening speed of 20% until the distance between the front mold and the rear mold is 35 mm.

[0130] In the second mold opening stage, the mold is opened at a mold opening speed of 35% until the distance between the front mold and the rear mold is 85 mm.

[0131] In the third mold opening stage, the mold is opened at a mold opening speed of 40% until the distance between the front mold and the rear mold is 160 mm.

[0132] In the fourth mold opening stage, the mold is opened at a mold opening speed of 45% until the distance between the front mold and the rear mold is 400 mm.

[0133] In the fifth end mold opening stage, the mold is opened at a mold opening speed of 25% until the distance between the front mold and the rear mold is 450 mm.

[0134] The ejector is then controlled to push the molded part out 40mm, hold it there for 1.2 seconds, and then push it forward to 57mm, hold it there for 1.2 seconds, completing the molding of the plastic product. This process is repeated to execute the next injection molding cycle.

[0135] Please refer to Figure 7, which is a comparison diagram of the temperature change curve of the molding mold at each stage during molding in this embodiment and the temperature change curve of the traditional process. Combined with the surface radius, pit size and roughness measured after scanning the bottom surface of the microstructure using a white light interferometer shown in Figures 8 to 10, the morphology and structural dimensions of the microstructure shown in Figures 11 to 12, and the maximum contour curve of the microstructure surface shown in Figure 14, it can be clearly seen from the figure that the new surface microstructure of the present invention has a higher molding height and roughness, and each protrusion has a full shape and can effectively absorb and reflect incident light. Compared with the microstructure morphology obtained by the traditional process shown in Figure 13, the protrusions of the microstructure obtained in this embodiment are obviously more compactly arranged, the gaps are smaller, and the molding is fuller.

[0136] Another embodiment of the present invention provides an application of a novel surface microstructure on the inner surface of a plastic product, or an application of the molding process of the novel surface microstructure of the above embodiment on a plastic product, to achieve diffuse reflection of incident light on the inner surface of the plastic product.

[0137] Please refer to Figure 15, which is a schematic diagram of the structure of the plastic product to which the novel surface microstructure of this embodiment is applied. The plastic product is arranged on the light-entering side of the camera module and has an overall structure in the shape of a trumpet. The trumpet-shaped structure can collect light and then diffusely reflect the incident light through the novel surface microstructure integrated thereon, thereby reducing the reflective effect of the surface and preventing invalid light and stray light from entering the camera module. It is understandable that although this embodiment mainly uses a trumpet-shaped plastic product to illustrate the application of the novel surface microstructure, the application of the novel surface microstructure is not limited to this, and can also be used on other plastic products or even metal products that require diffuse reflection.

[0138] Specifically, the plastic product has a main body 21 connected to the camera module, and a light hole 21a coaxial with the optical axis of the camera module is formed on the main body 21 of the plastic product. The main body 21 has a light-facing surface 22a facing inward (i.e., facing the axis direction of the light hole or the optical axis direction of the camera module) and a backlight surface 22b arranged away from the light-facing surface 22a. The light-facing surface 22a is integrally formed with the novel surface microstructure to perform multiple reflections on the light incident on the light-facing surface 22a. In this embodiment, the novel surface microstructure is formed by integrally molding with the plastic product. During the molding process, the main body 21 of the plastic product is formed by a conventional injection molding process, and the novel surface microstructure is formed by a rapid cooling and heating process. The two-step process can be integrated into the same set of molds. During the specific molding process, the molding temperature of the process stage can be adjusted to achieve compatibility of the two-step process, thereby simplifying the process flow and process difficulty of plastic product and microstructure processing.

[0139] Please refer to Figure 16, which models and simulates the diffuse reflection of plastic products using the new surface microstructure or the above-mentioned process. It can be seen that parallel light will be reflected multiple times after directly hitting the microstructure surface, but very little light will enter the lens below.

[0140] Another embodiment of the present invention provides a plastic product with a novel surface microstructure for use in a camera module. By placing the plastic product with the novel surface microstructure on the light-entering side of the camera module's lens, the product is used to reflect and absorb light that does not enter the lens perpendicularly, thereby reducing glare. The light aperture in the plastic product is coaxial with the optical axis of the lens. The microstructure on the plastic product reflects incident light, thereby reducing ineffective light or stray light from entering the lens and improving the camera module's imaging quality.

Claims

1. A novel surface microstructure, comprising a substrate integrally formed on a light-facing surface of a plastic product, wherein the substrate has a first surface disposed opposite to the light-facing surface, characterized in that: It also includes a microstructure layer integrally formed on the first surface of the substrate, the microstructure layer includes at least one first microstructure region, the first microstructure region includes a plurality of first microstructure units arranged on the substrate according to a first rule, and the surface of the first microstructure unit is a spherical structure protruding in a direction away from the substrate.

2. The novel surface microstructure according to claim 1, characterized in that: The novel surface microstructure is integrally formed with the substrate into a plastic product, wherein the novel surface microstructure is formed by a rapid cooling and heating process.

3. The novel surface microstructure according to claim 2, characterized in that: The radius of the projection of the first microstructure unit on the first surface is 75*(1±15%) μm, and the height tolerance of the projection of the first microstructure unit on the plane perpendicular to the first surface satisfies the following conditions: R*90%≤H≤R*110%; Wherein: R is the radius of the projection of the first microstructure unit on the first surface, and H is the height of the projection of the first microstructure unit on the plane perpendicular to the first surface.

4. The novel surface microstructure according to claim 1, characterized in that: A plurality of first microstructure units are distributed in an array of M rows and N columns, and a line connecting the geometric centers of projections of the first microstructure units of each row on the first surface is orthogonal to a line connecting the geometric centers of projections of the first microstructure units of each column on the first surface; and a spacing between the geometric centers of projections of the first microstructure units of two adjacent rows and / or two adjacent columns on the first surface is 0.14 to 0.18 mm.

5. The novel surface microstructure according to claim 1, characterized in that: The microstructure layer also includes at least one second microstructure area integrally formed on the substrate and corresponding to the side of the first microstructure area, the first microstructure area intersects with the second microstructure area and is distributed in an array on the substrate; the second microstructure area includes a plurality of second microstructure units arranged on the substrate according to a second rule, and the surface of the second microstructure unit is a spherical structure protruding in a direction away from the substrate.

6. The novel surface microstructure according to claim 5, characterized in that: The radius of the projection of the second microstructure unit on the first surface is 75*(1±15%) μm, and the height tolerance of the projection of the second microstructure unit on the plane perpendicular to the first surface satisfies the following conditions: R'*90%≤H'≤R'*110%; Wherein: R' is the radius of the projection of the second microstructure unit on the first surface, and H' is the height of the projection of the second microstructure unit on the plane perpendicular to the first surface.

7. The novel surface microstructure according to claim 5, characterized in that: A plurality of second microstructure units are arranged in m rows, and in two adjacent rows of second microstructure units, the angle between a line connecting the geometric centers of projections of the second microstructure units of each row on the first surface and a line connecting the geometric centers of projections of the second microstructure units of each column on the first surface is less than 90°; and the spacing between the geometric centers of projections of the second microstructure units of two adjacent rows and / or two adjacent columns on the horizontal plane is 0.14 to 0.18 mm.

8. The novel surface microstructure according to claim 5, characterized in that: The surface roughness of the bottom surface of any microstructure unit in the bottom surface of the first microstructure region and / or the second microstructure region is Ra≥0.1 μm.

9. A new type of surface microstructure forming process, characterized in that: The following steps are involved: Add injection molding materials into the barrel, plasticize and complete metering; Closing the mold and preheating the mold cavity surface to a first preset temperature, wherein the first preset temperature is greater than the Tg temperature of the injection molding material; Filling the injection molding material in the barrel into the mold cavity to form an injection molded part; After filling is completed, switch to the pressure holding state to hold the pressure of the injection molded part; After the pressure holding is completed, the cooling channel is opened to cool the mold and the injection molded part to a second preset temperature; Open the mold and eject the injection molded part.

10. The forming process of the novel surface microstructure according to claim 9 is characterized in that: Before the step of adding the injection molding raw material into the barrel, plasticizing and completing the metering, the following steps are also included: The barrel temperature and hot runner temperature of the mold are set and the barrel and the hot runner are preheated with the set barrel temperature and hot runner temperature; wherein the barrel has a nozzle section, a fourth heating section, a third heating section, a second heating section, a first heating section and a feed port section which are arranged in sequence, and the temperatures of the barrel corresponding to the nozzle section, the fourth heating section, the third heating section, the second heating section, the first heating section and the feed port section are set to 295-315°C, 295-315°C, 290-310°C, 280-300°C, 270-290°C and 260-280°C respectively, and the hot runner temperature is 290-330°C.

11. The forming process of the novel surface microstructure according to claim 9, characterized in that: In the steps of adding injection molding raw materials into the barrel, plasticizing and completing metering, multi-stage metering is adopted when metering the injection molding raw materials. During the metering process, the rotation speed of the screw in the barrel is 60*(1±20%)rpm, and the back pressure is 40*(1±20%)kgf / cm2. After the metering is completed, the screw is loosened and retracted, the loosening distance is 5±3mm, and the loosening speed is 15*(1±20%)mm / s.

12. The forming process of the novel surface microstructure according to claim 9, characterized in that: In the step of closing the mold and heating the mold cavity surface to a first preset temperature, a multi-stage mold closing is adopted. During mold closing, the front mold and the rear mold of the mold move relative to each other to a first mold closing position at a first mold closing pressure, then switch to a second mold closing pressure, and then move relative to each other until the mold closing is completed, wherein the first mold closing pressure is greater than the second mold closing pressure, and the mold closing speed decreases during the relative movement of the front mold and the rear mold of the mold; the first mold closing pressure is 230*30%*(1±20%)TON.

13. The forming process of the novel surface microstructure according to claim 9, characterized in that: In the step of closing the mold and heating the mold cavity surface to a first preset temperature, the first preset temperature is 135-145° C., and the heating power is 8-15 KW.

14. The forming process of the novel surface microstructure according to claim 9, characterized in that: In the step of filling the injection molding raw material in the barrel into the mold cavity to form the injection molded part, segmented filling is adopted. During the filling: The filling pressure of the first filling stage is 2300*(1±20%)kgf / cm2, the filling speed is 20*(1±20%)mm / s, and the filling is from the metering completion position to the first filling position or the maximum filling time, wherein the first filling position is 52±3mm, and the maximum filling time is 3*(1±20%)s; The filling pressure of the second filling stage is 2300*(1±20%)kgf / cm2, the filling speed is 45*(1±20%)mm / s, and the filling is from the first filling position to the second filling position or the maximum filling time is reached, wherein the second filling position is 12±3mm; The filling pressure of the third end filling stage is 2300*(1±20%)kgf / cm2, and the filling speed is 25*(1±20%)mm / s. It is filled from the second filling position to the pressure holding switching position or reaches the maximum filling time, wherein the pressure holding switching position is 6±3mm.

15. The forming process of the novel surface microstructure according to claim 9, characterized in that: In the step of switching to the pressure holding state to hold the injection molded part after the filling is completed, a segmented pressure holding is adopted. During the pressure holding: The holding speed of the first holding stage is 25*(1±15%)mm / s, the holding time is 1.3*(1±20%)s, and the holding pressure is 1000*(1±15%)kgf / cm2; The holding speed of the second holding stage is 25*(1±15%)mm / s, the holding time is 2*(1±20%)s, and the holding pressure is 900*(1±15%)kgf / cm2.

16. The forming process of the novel surface microstructure according to claim 9, characterized in that: In the step of opening the cooling channel and cooling the mold and the injection molded part to the second preset temperature after the pressure holding is completed, the cooling time is 30*(1±20%)s, and the second preset temperature is 85-95°C.

17. The forming process of the novel surface microstructure according to claim 9, characterized in that: In the step of opening the mold and ejecting the injection molded part, a multi-stage mold opening is adopted. When opening the mold, the mold opening speed of the front mold and the rear mold of the mold during relative movement first increases and then decreases to the maximum mold opening position, and then the injection molded part is ejected and demolded by the ejector pin.

18. Application of the novel surface microstructure as described in any one of claims 1 to 8 on the inner surface of a plastic product and / or application of the novel surface microstructure prepared by the molding process of the novel surface microstructure as described in any one of claims 9 to 17 on the inner surface of a plastic product to achieve diffuse reflection and absorption of incident light on the inner surface of the plastic product.

19. Use of the plastic product as described in claim 9 in a camera module and / or use of a new surface microstructure prepared by the molding process of the new surface microstructure as described in any one of claims 9 to 17 in a camera module to reflect and absorb light that is not vertically incident on the camera module.

Images