Preparation mold and preparation method of resin prism optical element

Abstract

The invention discloses a preparation mold and a preparation method of a resin prism optical element, the mold comprises a double-color prism injection mold or a single-color prism injection mold, the mold is composed of a fixed mold and a movable mold, the fixed mold of the double-color prism injection mold is divided into a first punching station and a second punching station, and the movable mold is divided into a first mold and a second mold; station cavities with different shapes are formed between the movable mold plates and the corresponding fixed mold plates; a movable mold plate and a fixed mold plate of the monochromatic prism injection mold are combined together to form a product mold cavity, and an area needing extinction treatment in the mold cavity is a mold cavity dermatoglyph / frosted area. The resin triangular prism is prepared by adopting an injection molding process, the manufacturing of the triangular prism can be completed only through one procedure, the steps are simple, the mold is matched with the preparation process, the forming process can be greatly simplified, and the prepared resin triangular prism optical element has the performance similar to that of a glass triangular prism optical element; and various optical structures of various shapes, planes, spherical surfaces, aspheric surfaces, free-form surfaces and the like can be manufactured on various optical surfaces of the prism, so that the prism is suitable for being applied to the field of precision optics.

Description

Technical Field

[0001] The invention relates to a precision optical prism, in particular to a preparation mold for a resin prism optical element. The invention also relates to a preparation method for the resin prism optical element. Background Art

[0002] A prism generally has a main structure with three rectangular surfaces and two triangular surfaces. The two triangular surfaces of the main structure and a circle around the light-incoming surface generally need to be subjected to a certain degree of extinction treatment to form an extinction area, which is used to prevent stray light from entering the prism from positions other than the entrance part and interfering with the imaging effect.

[0003] The application of prism optical components is becoming more and more extensive, for example, there is an increasing demand in the fields of vision correction, videography, optical instrument testing, etc. The traditional prism manufacturing material is mainly glass, especially in the field of precision optical applications, such as mobile phone periscope cameras.

[0004] Glass prism optical elements have the characteristics of high thermal stability and high light transmittance. A lot of related research has been conducted in the industry. Its preparation process mainly includes material roughing, multi-pass grinding, rough polishing and fine polishing, blackening and other processes. Although the multi-process processing can ensure the product accuracy, the entire process is too cumbersome and the direct yield rate is very low. As the optical lens has higher and higher requirements for product performance and volume, higher requirements are also put forward for prisms accordingly. For example, some complex structures, aspherical surfaces, free-form surfaces or spherical surfaces are made on the light-inlet and light-outlet surfaces of the glass prism. Therefore, the required preparation process will be more complicated or even impossible to complete, and it cannot meet the needs of large-scale mass production of products. In addition, glass prisms have problems such as heavy glass material and expensive optical glass, which limits their further promotion, especially in the field of consumer electronics.

[0005] Compared with glass materials, resin materials are lighter and cheaper, and are gradually gaining attention in the application of prisms. However, the use of this material in the industry to prepare prisms has problems such as low preparation accuracy and cumbersome processes, and cannot be used in the field of precision optics. If conventional injection molding technology is used, there are the following disadvantages: Disadvantage 1: Because the thickness of the prism is uneven, the thickness in the center area is the largest, and the thickness in the edge area is the thinnest. The overall thickness is large and uneven. Conventional injection molding is prone to uneven shrinkage, resulting in poor product surface accuracy.

[0006] Disadvantage 2: The injection-molded prism still needs a second process: blackening the edges, which not only increases the labor cost, but also increases the defective loss in the production process. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a preparation mold and a preparation method for a resin prism optical element. The mold, combined with the preparation process, can greatly simplify the molding process. The prepared resin prism optical element has performance similar to that of a glass prism optical element and is suitable for application in the field of precision optics.

[0008] In order to solve the above technical problems, the first technical solution adopted by the present invention is: a preparation mold for a resin prism optical element, which is a two-color prism injection mold, including a fixed mold and a movable mold, the fixed mold is divided into a first working station and a second working station, each working station is respectively provided with a hot runner plate on the lower end surface of the fixed mold base plate, and a template is respectively set on the lower end surface of each hot runner plate, the first working station is used for molding the prism main structure, and the second working station is used for molding the extinction area; the movable mold is divided into a No. 1 mold and a No. 2 mold, the No. 1 mold and the No. 2 mold are respectively provided with ejection mechanisms on the movable mold base plate, a compression mechanism is respectively provided on each ejection mechanism, and a movable template is respectively provided on each compression mechanism; a station cavity of different shapes is formed between the movable template and its corresponding fixed template, one end of each station cavity is connected to the corresponding station hot nozzle, and each station hot nozzle is connected to the corresponding mold gate sleeve on the fixed mold base plate.

[0009] The first punching position of the fixed mold and the movable mold are combined to form a first punching position cavity for injecting transparent materials, and the second punching position of the fixed mold and the movable mold are combined to form a second punching position cavity for injecting black materials.

[0010] The compression mechanism is a compression plate, a compression spring is arranged between the compression plate and the corresponding movable plate, and a compression gap of about 2 to 4 mm is left between the compression plate and the movable plate.

[0011] The compression mechanism is provided with a compression ejector rod and a common ejector rod on the ejection mechanism, and a compression mold core is provided at the other end of the compression ejector rod.

[0012] The shapes of the No. 1 mold and the No. 2 mold of the movable mold are exactly the same, and the shapes of the first punching position and the second punching position of the fixed mold are different.

[0013] A 100mm heat insulation gap is provided between the first striking position and the last striking position of the fixed mold.

[0014] The mold is provided with a central rotation axis, and the first mold and the second mold of the movable mold are centrally symmetrical with respect to the rotation axis.

[0015] The method for preparing a prism by using the above-mentioned resin prism optical element preparation mold of the present invention comprises the following steps: (1). The movable platen of mold No. 1 is in the first working position, and together with the fixed platen of the first working position, it forms the first working position cavity. The movable platen of mold No. 2 is in the second working position, and together with the fixed platen of the second working position, it forms the second working position cavity. The barrel of the first working position is made of transparent material, and the barrel of the second working position is made of black material. (2) Adjust the clamping force of the two-color injection molding machine with mold clamping compression function. When the mold is manually closed with this clamping force, the mold should be closed to the bottom and the compression gap spacing should be 0; (3) Set the clamping force of the injection molding machine in compression standby mode to 1 / 3 of the normal clamping force. In this way, the fully automatic start will leave a compression gap of 0.1 to 0.2 mm between the compression mechanism and the movable platen, and the resin material will be injected into the corresponding cavity through the corresponding mold gate sleeve and station hot nozzle; (4) When the cavity is filled to more than 99% and the pressure is switched to hold, the clamping part of the injection molding machine starts to switch to the first stage of compression mode: expansion. A smaller compression force is used first. At this time, as the cavity is gradually filled, the pressure in the mold gradually increases, exceeding the clamping force, and the pressure is transmitted to the compression mechanism through the compression mold core, driving the compression mechanism to retreat. The compression gap between the compression mechanism and the moving template will gradually expand to 0.2-0.3 mm. (5) Entering the second stage of compression mode: compression, the clamping part of the injection molding machine gradually increases the clamping force, gradually exceeds the cavity pressure, and then drives the compression mechanism forward, the compression gap is reduced, and the compression mold core uniformly compresses and thins the product, until the compression gap is reduced to close to 0; (6). After cooling for a period of time, the mold is opened again, and then the movable mold side is rotated 180°. The movable mold plate of mold No. 1 is rotated to the rear punching position. The product that has been punched out in mold No. 1 and the fixed mold plate of the rear punching position form the cavity of the rear punching position. The movable mold plate of mold No. 2 is rotated to the first punching position and forms the cavity of the first punching position with the fixed mold plate of the first punching position. (7) The back working station starts to inject black material, while the front working station starts to inject transparent material; (8). After cooling, the mold is opened, the ejection mechanism at the rear working position moves forward, and the ejector rod is driven forward to eject the product; (9). The movable mold rotates 180° again to start the next cycle.

[0016] The second technical solution adopted by the present invention is: a preparation mold for a resin prism optical element, which is a monochrome prism injection mold, including a fixed mold and a movable mold, the fixed mold includes a fixed mold base plate, a hot runner plate and a fixed mold plate, and the movable mold includes a movable mold base plate, an ejection mechanism, a compression plate, and a movable mold plate; the fixed mold base plate is arranged above the hot runner plate, and a hot nozzle and a valve needle are arranged in the hot runner plate, and the fixed mold plate is arranged below the hot runner plate, and the valve needle and the hot nozzle pass through the hot runner plate and the fixed mold plate; the movable mold plate is arranged above the compression plate, and the movable mold plate and the fixed mold plate are combined to form a product cavity, and the area in the cavity that needs to be matte treated is the cavity leather grain / frosted area, the compression plate is located below the movable mold plate, and a compression spring is arranged in the compression plate, and below the compression plate is the ejection mechanism, and below the ejection mechanism is the movable mold base plate.

[0017] The present invention utilizes the above-mentioned method for preparing a prism by preparing a mold for a resin prism optical element, performs a leather grain / frosted treatment on the mold corresponding to the area of ​​the product that needs to be matted, and heats the mold after installing it in the clamping part of an injection molding machine to meet the drying temperature and time required by the resin material, then the cycle starts, the clamping force of the injection molding machine is set to 1 / 3 of the normal clamping force of the product, and after the mold is closed, the injection part of the injection molding machine injects the molten resin into the mold again, and after the resin fills 99% of the cavity, the injection part of the injection molding machine switches to pressure holding, and at the same time or 1 to 2 seconds later, the clamping part also gradually increases the pressure until the normal clamping force required by the product is reached, and the product is compressed, and the compression amplitude is 0.1 to 0.2 mm. Under sufficient holding and compression pressures, the resin will effectively copy the shape of the mold surface, including the light-transmitting area and the leather grain / frosted area, and after cooling, the solidified product has the shape designed by the mold, including the light-transmitting area and the leather grain / frosted area that needs to be matted.

[0018] The present invention adopts a preparation mold and a preparation method of a resin triangular prism optical element designed by the above technical solution, which has the following beneficial technical effects: (1) The present invention prepares a precision prism optical element by injection molding, and the resin material used is an optical resin with stable physical and chemical properties such as polycarbonate (PC) or cycloolefin copolymer (COC). These materials have good physical and chemical stability and can maintain very good stability during the long-term use of the product. In addition, compared with glass materials, they are cheaper and lighter in weight; (2) The present invention replaces the traditional glass roughing, grinding, rough polishing, fine polishing, blackening and other multiple processes through a simple and efficient injection molding method. The production cycle only takes tens of seconds, and more than a dozen or even more holes can be made on the injection mold, which can ensure that multiple holes can be produced from one mold. The traditional glass prism manufacturing requires a production cycle of more than 48 hours. At the same time, it is precisely because of the traditional cumbersome process of glass prisms that the straight-through rate is very low. The present invention only needs one step to manufacture the prism, so the process yield is very high, which improves the efficiency of prism production and is very suitable for large-scale, low-cost mass production; (3) The present invention processes complex optical structures on the surface of the injection mold, such as spherical surfaces, aspherical surfaces, free-form surfaces and other optical structures. Through a simple injection molding process, prisms with various optical properties can be efficiently prepared, and complex glass prism structures that cannot be made by traditional cold processing can be realized, thereby simplifying the volume of optical products and realizing more optical functions of products. (4) Although some people in the industry have begun to study the injection molding method to prepare prisms, the product accuracy is completely unable to meet the needs of precision optical applications. The present invention uses a compression injection molding mold and a compression injection molding process, which can greatly improve the surface accuracy of the prism product while ensuring high molding efficiency. The surface accuracy can be less than 100nm, reaching the same level as glass prisms; (5) The present invention designs a special injection mold and cooperates with the corresponding injection molding process to ensure that during the cooling and shrinkage process of the resin material, the thinner area and the thicker area are always subjected to a balanced holding pressure, ensuring that the deformation of different areas is consistent, thereby controlling the surface accuracy of the product to be less than 100nm, reaching the same level as glass components. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram showing the structure of a two-color prism injection mold for mold clamping and compression according to the present invention; Figure 2 A schematic diagram showing a planar prism of the present invention; Figure 3 A schematic diagram showing an aspherical or spherical prism of the present invention; Figure 4 A schematic diagram showing another planar triangular prism of the present invention; Figure 5 A schematic diagram showing the structure of the ejection and compression two-color prism injection mold of the present invention; Figure 6 A schematic structural diagram showing a single-color injection mold of the present invention; Figure 7 A schematic diagram of a prism subjected to the roughening treatment of the present invention is shown.

[0020] In the figure: 10-fixed mold base plate, 11-first mold gate sleeve, 12-later mold gate sleeve, 20-first work station hot runner plate, 21-first work station hot nozzle, 22-first work station needle valve glue inlet, 23-later work station hot runner plate, 24-later work station hot nozzle, 25-later work station needle valve glue inlet, 30-first work station fixed template, 31-first work station cavity (grid line filling area), 32-later work station fixed template, 33-later work station cavity (oblique line filling area), 40-No. 1 mold dynamic template, 41-No. 2 mold dynamic template, 50-No. 1 mold compression plate, 51-No. 1 mold compression spring, 52-No. 2 mold compression plate, 53-No. 2 mold compression spring, 54 No. 1 mold support plate, 55 No. 2 mold support plate, 60-No. Mold ejection mechanism, 61-mold ejection mechanism No. 2, 62-mold ejection compression core, 63-mold compression ejector, 64-mold ordinary ejector, 65-mold ordinary ejector reserved compression gap, 66-mold compression core, 67-mold compression ejector, 68-mold ordinary ejector, 69-mold ordinary ejector reserved compression gap, 70-movable mold seat plate, 80-insulation gap, 90-center rotation axis, 201-hot runner plate, 211-hot runner manifold, 221-valve needle, 241-hot nozzle, 301-fixed mold plate, 311-cavity leather grain / frosted area, 401-movable mold plate, 501-compression plate, 511-compression spring, 521-compression gap, 601-ejection mechanism. DETAILED DESCRIPTION

[0021] The following is a detailed description of a mold and a method for preparing a resin prism optical element according to the present invention in conjunction with the accompanying drawings.

[0022] The present invention uses a transparent optical resin as the main structure of the prism. After the resin material is melted, the material is injected into a molding mold, and taken out after cooling to prepare a precision optical prism. The light-transmitting resin material selected for the main body includes optical resins with stable physical and chemical properties such as polycarbonate (PC) or cycloolefin copolymer (COC), but is not limited to the above resin materials. The refractive index of the above resin material can be from 1.48 to 1.71. It can be understood that although the optical refractive index of the resin material is lower than that of the glass material, the refractive index of the above optical resin can meet the requirements for prisms used in reflection, total reflection, and refraction light paths. The present invention ensures that the thinner area and the thicker area of ​​the resin material are always subjected to a balanced holding pressure during the cooling and shrinking process, and ensures that the deformation of different areas is consistent, thereby controlling the surface accuracy of the product to be less than 100nm, reaching the same level as glass components.

[0023] Embodiment 1 of the present invention is a preparation mold and preparation method of a resin triangular prism optical element. This embodiment adopts a mold with a mold-closing and compression function, and is matched with an injection molding machine with a mold-closing and compression function, and is realized through a mold-closing and compression process. Figure 1 , including fixed mold and movable mold, the fixed mold is divided into the first working position and the last working position, the movable mold is divided into mold No. 1 and mold No. 2, a total of four parts. The first and second molds of the movable mold have the same shape, and the first and last working positions of the fixed mold have different shapes.

[0024] The fixed mold first working position includes a fixed mold base plate 10, a first working position hot runner plate 20, a first working position hot nozzle 21, a first working position needle valve glue inlet 22, and a first working position fixed mold plate 30. The first working position hot runner plate 20 is arranged on the lower end surface of the fixed mold base plate 10, and the first working position fixed mold plate 30 is connected to the lower end surface of the first working position hot runner plate 20. The fixed mold back working position includes a fixed mold base plate 10, a back working position hot runner plate 23, a back working position hot nozzle 24, a back working position needle valve glue inlet 25, and a back working position fixed mold plate 32. The back working position hot runner plate 23 is arranged on the lower end surface of the fixed mold base plate 10, and the back working position fixed mold plate 32 is connected to the lower end surface of the back working position hot runner plate 23. The first working position and the back working position of the present invention share a fixed mold base plate 10.

[0025] The movable mold No. 1 comprises a movable mold plate No. 1 40, a compression plate No. 1 50, a compression spring No. 1 51, an ejection mechanism No. 1 60, and a movable mold base plate 70. The ejection mechanism No. 1 60 is arranged on the movable mold base plate 70, the ejection mechanism No. 1 60 is provided with a compression plate No. 1 50, the movable mold plate No. 1 40 is provided on the compression plate No. 1 50, and a compression gap No. 1 54 is left between the compression plate No. 1 50 and the movable mold plate No. 1 40. The movable mold No. 2 comprises a movable mold plate No. 2 41, a compression plate No. 2 52, a compression spring No. 2 53, an ejection mechanism No. 2 61, and a movable mold base plate 70. The second mold ejection mechanism 61 is arranged on the movable mold base plate 70, the second mold ejection mechanism 61 is provided with a second mold compression plate 52, the second mold compression plate 52 is provided with a second mold movable plate 41, and a second mold compression gap 55 is left between the second mold compression plate 52 and the second mold movable plate 41. The first mold and the second mold of the present invention share a movable mold base plate 70.

[0026] The fixed mold first working station of the present invention can form a first working station cavity 31 (triangular prism transparent color area) after the fixed mold first working station and the movable mold are combined, and the fixed mold second working station and the movable mold can form a second working station cavity 33 (triangular prism black area) after the fixed mold second working station and the movable mold are combined.

[0027] One end of the first-working position cavity 31 is connected to the first-working position hot nozzle 21 through the first-working position needle valve glue inlet 22, and the first-working position hot nozzle 21 is connected to the first-working mold gate sleeve 11 on the fixed mold base plate 10, and the first-working position hot nozzle 21 is set in the cavity of the first-working position hot runner plate 20. One end of the second-working position cavity 33 is connected to the second-working position hot nozzle 24 through the second-working position needle valve glue inlet 25, and the second-working position hot nozzle 24 is connected to the second-working mold gate sleeve 12 on the fixed mold base plate 10, and the second-working position hot nozzle 24 is set in the cavity of the second-working position hot runner plate 23.

[0028] A first mold compression spring 51 is connected between the first mold compression plate 50 and the corresponding first mold movable plate 40 , and a second mold compression spring 53 is connected between the second mold compression plate 52 and the corresponding second mold movable plate 41 .

[0029] A 100 mm heat insulation gap 80 is provided between the first and second working positions of the fixed mold of the present invention. The mold has a central rotation axis 90, and the first and second molds of the movable mold are centrally symmetrical with respect to the central rotation axis 90.

[0030] This mold compression mold needs to use the mold compression process and needs to be used with an injection molding machine with a mold compression function. The specific implementation method is: 1. In the initial state, the movable mold plate No. 1 is in the first working position, and forms the first working position cavity with the fixed mold plate of the first working position. The movable mold plate No. 2 is in the second working position, and forms the second working position cavity with the fixed mold plate of the second working position. The barrel of the first working position is transparent material, and the barrel of the second working position is black material; 2. Adjust the appropriate clamping force according to the product requirements. When manually closing the mold with this clamping force, the mold should be able to close to the bottom and the compression gap spacing should be 0; 3. The clamping force of the compression standby is set to about 1 / 3 of the normal clamping force. In this way, the fully automatic start, when the mold is closed, the clamping part of the injection molding machine will be on standby when it reaches about 1 / 3 of the normal clamping force. At this time, the compression gap (54, 55) between the compression plate and the movable plate will leave a spacing of 0.1 to 0.2 mm. During the injection filling process, this clamping force is sufficient to ensure that the parting surface does not overflow the flash; 4. When the cavity is filled to more than 99%, when switching to holding pressure, the clamping part of the injection molding machine starts to switch to the first stage of compression mode: expansion. First, use a smaller compression force. At this time, as the cavity is gradually filled, the pressure in the mold gradually increases, exceeding the clamping force, and the pressure is transmitted to the compression plate through the compression mold core, driving the compression plate to retreat, so that the compression gap between the compression plate and the moving template will gradually expand to about 0.2-0.3mm; 5. Enter the second stage of compression mode: compression. The clamping part of the injection molding machine will gradually increase the clamping force, gradually exceeding the cavity pressure, and then drive the compression plate forward, the compression gap will be reduced, and the compression mold core will evenly compress and thin the product until the compression gap is reduced to nearly 0; 6. After cooling for a while, open the mold again, and then rotate the movable mold side 180°. The movable mold plate of mold No. 1 rotates to the rear punching position. The product punched out of mold No. 1 and the fixed mold of the rear punching position form the cavity of the rear punching position. The movable mold plate of mold No. 2 rotates to the first punching position and forms the cavity of the first punching position with the fixed mold of the first punching position. 7. The back working station starts to inject black material, while the front working station starts to inject transparent material; 8. After cooling, the mold is opened, the ejector mechanism at the rear working position moves forward, drives the ejector rod forward, and ejects the product; 9. The movable mold rotates 180° again to start the next cycle.

[0031] The present invention Figure 2 , Figure 3 , Figure 4 In the figure, the upper picture shows the product shape produced by cavity injection molding first (transparent material, main structure), the oblique line area in the lower part of the picture shows the product shape produced by cavity injection molding later (black material, matte area), and the oblique line plus the transparent area is the final product shape produced by injection molding.

[0032] The light inlet and outlet surfaces of the resin prism manufactured in Example 1 can be manufactured into a planar structure.

[0033] Embodiment 2 of the present invention is a preparation mold and preparation method of a resin triangular prism optical element. This embodiment adopts a mold with an ejection compression function and an injection molding machine with an ejection compression function to achieve the ejection compression process. Figure 5 , including fixed mold and movable mold, the fixed mold is divided into the first working position and the last working position, the movable mold is divided into mold No. 1 and mold No. 2, a total of four parts. The shapes of the movable mold No. 1 and mold No. 2 are exactly the same, and the shapes of the first working position and the last working position of the fixed mold are different.

[0034] The fixed mold first working position includes a fixed mold base plate 10, a first working position hot runner plate 20, a first working position hot nozzle 21, a first working position needle valve glue inlet 22, and a first working position fixed mold plate 30. The first working position hot runner plate 20 is arranged on the lower end surface of the fixed mold base plate 10, and the first working position fixed mold plate 30 is connected to the lower end surface of the first working position hot runner plate 20. The fixed mold back working position includes a fixed mold base plate 10, a back working position hot runner plate 23, a back working position hot nozzle 24, a back working position needle valve glue inlet 25, and a back working position fixed mold plate 32. The back working position hot runner plate 23 is arranged on the lower end surface of the fixed mold base plate 10, and the back working position fixed mold plate 32 is connected to the lower end surface of the back working position hot runner plate 23. The first working position and the back working position of the present invention share a fixed mold base plate 10.

[0035] The movable mold No. 1 comprises a movable mold plate 40, a mold support plate 54, a mold ejection mechanism 60, and a movable mold base plate 70. The mold ejection mechanism 60 is arranged on the movable mold base plate 70, the mold ejection mechanism 60 is provided with a mold support plate 54, and the mold support plate 54 is provided with the movable mold plate 40. The mold ejection mechanism is provided with a mold compression core 62, a mold compression ejector 63, and a mold common ejector 64. The mold common ejector 64 is divided into two sections, one section is fixed on the mold ejection mechanism 60, and the other section is fixed on the mold support plate 54, and a compression gap 65 for the mold common ejector is reserved between the two sections.

[0036] The movable mold No. 2 mold comprises a movable mold plate No. 2 41, a mold support plate No. 2 51, a mold ejection mechanism No. 2 61, and a movable mold base plate 70. The mold ejection mechanism No. 2 61 is arranged on the movable mold base plate 70, the mold ejection mechanism No. 2 61 is provided with a mold support plate No. 2 55, the mold support plate No. 2 41 is provided on the mold support plate No. 2 51, the mold ejection mechanism No. 2 61 is provided with a mold compression core No. 2 66, a mold compression ejector No. 2 67, and a mold common ejector No. 2 68, the mold common ejector No. 2 68 is divided into two sections, one section is fixed on the ejection mechanism 61, and the other section is fixed on the mold support plate No. 2 55, and a compression gap 69 is reserved between the two. The first mold and the second mold of the present invention share a movable mold base plate 70.

[0037] After the fixed mold first working station and the movable mold are combined, they can form the first working station cavity 31 (prism transparent color area), and after the fixed mold rear working station and the movable mold are combined, they can form the rear working station cavity 33 (prism black area).

[0038] One end of the first-working position cavity 31 is connected to the first-working position hot nozzle 21 through the first-working position needle valve glue inlet 22, and the first-working position hot nozzle 21 is connected to the first-working mold gate sleeve 11 on the fixed mold base plate 10, and the first-working position hot nozzle 21 is set in the cavity of the first-working position hot runner plate 20. One end of the second-working position cavity 33 is connected to the second-working position hot nozzle 24 through the second-working position needle valve glue inlet 25, and the second-working position hot nozzle 24 is connected to the second-working mold gate sleeve 12 on the fixed mold base plate 10, and the second-working position hot nozzle 24 is set in the cavity of the second-working position hot runner plate 23.

[0039] A 100 mm heat insulation gap 80 is provided between the first and second working positions of the fixed mold of the present invention. The mold has a central rotation axis 90, and the first and second molds of the movable mold are centrally symmetrical with respect to the central rotation axis 90.

[0040] The compression process used in this mold is specifically implemented by: 1. First, the movable mold plate of the first mold is in the first working position, and forms the first working position cavity with the fixed mold plate of the first working position. The movable mold plate of the second mold is in the last working position, and forms the last working position cavity with the fixed mold plate of the last working position. The barrel of the first working position is transparent material, and the barrel of the last working position is black material; 2. Pre-set the compression ejector stroke, which can be set within 0.1 to 2 mm; 3. Use normal injection to fill the first working position cavity to about 99%, and then switch to pressure holding; 4. After holding the pressure for 5 to 10 seconds, the first punching station starts ejection compression, and the ejection mechanism drives the compression ejector and the compression mold core forward to compress the first punching station cavity; 5. After cooling for a while, open the mold again, and then rotate the movable mold side 180°. The movable mold plate of mold No. 1 rotates to the rear punching position. The product punched out of mold No. 1 and the fixed mold of the rear punching position form the cavity of the rear punching position. The movable mold plate of mold No. 2 rotates to the first punching position and forms the cavity of the first punching position with the fixed mold of the first punching position. 6. The back working station starts to inject black material, while the front working station starts to inject transparent material; 7. After cooling, the mold is opened, and the ejection mechanism of the rear working position moves forward, driving the ordinary ejector rod to move forward. The reserved gap on the ordinary ejector rod gradually decreases and contacts, until the ordinary ejector rod ejects the product; 8. The movable mold rotates 180° again to start the next cycle.

[0041] Figure 2 , Figure 3 , Figure 4 This is the product picture.

[0042] In addition to the compression methods of the above two embodiments, the present invention may also have other compression methods to choose from: 1. Use common templates for standby compression, without setting up special compression plates and compression gaps. When closing the mold, leave a certain gap between the fixed and movable molds. To prevent flash, an interlaced surface needs to be set. When switching to pressure holding, continue closing the mold until it is tightly closed; 2. Use non-expansion compression plates for compression. There are also special compression plates and compression gaps, but a larger clamping force is used when closing the mold. There is no expansion process during pressure holding, and the compression gap is directly reduced to 0.

[0043] The light inlet and outlet surfaces of the resin prism manufactured in Example 2 can be manufactured into a planar structure.

[0044] Embodiment 3 of the present invention is a preparation mold and preparation method of a resin triangular prism optical element. In addition to the two-color injection molding method in the above embodiment, the present invention also has other methods that can replace the preparation process of the extinction area, see Figure 6 and Figure 7This mold is divided into a fixed mold and a movable mold. The fixed mold is further divided into a 10 fixed mold base plate, a 201 hot runner plate, and a 301 fixed mold plate. The movable mold is divided into a 70 movable mold base plate, a 601 ejection mechanism, a 501 compression plate, and a 401 movable mold plate. The fixed mold base plate 10 is above the hot runner plate 201. The hot runner plate 201 is provided with a hot nozzle 241 and a valve needle 221. The fixed mold plate 301 is below the hot runner plate 201. The valve needle 221 and the hot nozzle 241 penetrate the hot runner plate 201 and the fixed mold plate 301. The movable mold plate 401 is above the compression plate 501. The movable mold plate 401 and the fixed mold plate 301 are combined to form a product cavity. The area in the cavity that needs to be matte treated is the cavity leather grain / frosted area 311, corresponding to Figure 6 The compression plate 501 is located below the movable mold plate 401 , a compression spring 511 is arranged inside the compression plate 501 , an ejection mechanism 601 is located below the compression plate 501 , and a movable mold base plate 70 is located below the ejection mechanism 601 .

[0045] The process used in this mold is specifically implemented by: The mold corresponding to the area where the product needs to be matte treated has been treated with leather grain / frosted. After the mold is installed in the clamping part of the injection molding machine, it is heated to a reasonable temperature (taking PC resin as an example, the general mold temperature is 100-140°C). The resin material also needs sufficient drying temperature and time (taking PC resin as an example, generally 120°C, 4 hours). Then the cycle starts, and the injection molding machine first closes the mold with a lower clamping force (generally about 1 / 3 of the normal clamping force of the product. For example, if a general prism requires a 50-ton clamping force, only 10-20 tons of clamping force is required in the initial stage to ensure that the parting surface does not have flash.), After the mold is closed, the injection molding machine's injection part injects the molten resin into the mold. After the resin fills 99% of the cavity, the injection part of the injection molding machine switches to pressure holding (pressure holding is generally set to 5-20Mpa). At the same time or 1-2 seconds later than the pressure holding, the clamping part also gradually increases the pressure until the normal clamping force required by the product (for example, 50 tons) is reached, and the product is compressed, and the compression range is generally 0.1-0.2mm. Under sufficient holding and compression pressure, the resin will effectively copy the shape of the mold surface, including the light-transmitting area and the leather grain / frosted area. After a certain cooling time (generally 100 to 200 seconds), the solidified product will have the shape designed by the mold, including the light-transmitting area with strict surface requirements and the leather grain / frosted area that needs to be matte.

[0046] It is understandable that applying leather grain / frosting treatment to the surface of the injection mold is a very simple processing process. However, using this solution in the molding process of the prism optical element can greatly simplify the traditional blackening process of the prism optical element, and can also streamline the two-color injection molding process of the present invention, further improving the product preparation efficiency. Figure 2As shown, the transparent area of ​​the product is the main structure of the prism, and the shadow area of ​​the product is the corresponding matte area after two-color injection molding or leather grain / frosted treatment.

[0047] The light inlet and outlet surfaces of the resin prism manufactured in Example 3 can be manufactured into a planar structure.

[0048] Embodiment 4 of the present invention is a preparation mold and preparation method of a resin prism optical element. In the structure of embodiment 1 or embodiment 2, the shape of the light input and light output surfaces of the prism can be made into a shape in which the light input surface is an aspherical surface and the light output surface is a planar structure.

[0049] Embodiment 5 of the preparation mold and preparation method of a resin prism optical element of the present invention, in the structure of embodiment 1 or embodiment 2, the shape of the light input and light output surfaces of the prism can be made into a non-spherical structure for both the light input surface and the light output surface.

[0050] The comparison of the structures and product performances of different embodiments of the present invention is shown in Table 1: Table 1 Inlet and outlet light surface shape Surface accuracy of light entering surface / nm Light emitting surface accuracy / nm Reflective surface (all flat) surface accuracy / nm Angular accuracy tolerance / arc minute Material Example 1 flat 96 95 240 ±5 PC Example 2 flat 82 80 230 ±4 PC Example 3 flat 68 70 180 ±2 PC Example 4 Aspherical light-incoming surface, flat light-outgoing surface 100 80 250 ±3 PC Example 5 Both the light-entry and light-exit surfaces are aspherical 110 105 260 ±2.5 PC Comparative Example 1 flat 72 75 190 ±2 Glass

[0051] The present invention adopts an injection molding process to prepare a resin prism. The injection molding process can be two-color compression injection molding, in which a transparent resin material constitutes the main structure of the prism, and a black resin material constitutes the extinction area of ​​the prism. It can also be single-color compression injection molding, in which the non-skin grain / frosted transparent resin material area corresponds to the main structure of the prism, and the skin grain / frosted area corresponds to the extinction area of ​​the prism. The latter method does not require two-color injection molding, and the preparation process is simpler and more efficient. It can be understood that these two methods can also be applied simultaneously, which can improve the bonding force of the black injection molding layer on the one hand, and achieve a better extinction effect by superimposing the two effects on the other hand. Through the technical route of the present invention, various shapes, various optical structures such as planes, spherical surfaces, aspherical surfaces and free-form surfaces can be made on each optical surface of the prism, further expanding and supporting the application of the prism in the field of precision optics.

Claims

1. A mold for preparing a resin prism optical element, Its characteristics are A two-color prism injection mold comprises a fixed mold and a movable mold, wherein the fixed mold is divided into a first-strike station and a second-strike station, each station is provided with a hot runner plate on the lower end surface of the fixed mold base plate, and a template is set on the lower end surface of each hot runner plate, the first-strike station is used to form a prism main structure, and the second-strike station is used to form a matte area; the movable mold is divided into a first mold and a second mold, wherein the first mold and the second mold are provided with ejection mechanisms on the movable mold base plate, each ejection mechanism is provided with a compression mechanism, and each compression mechanism is provided with a movable template; station cavities of different shapes are formed between the movable template and its corresponding fixed template, one end of each station cavity is connected to a corresponding station hot nozzle, and each station hot nozzle is connected to a corresponding mold gate sleeve on the fixed mold base plate.

2. A mold for preparing a resin prism optical element according to claim 1, Its characteristics are The compression mechanism is a compression plate, a compression spring is arranged between the compression plate and the corresponding movable plate, and a compression gap of 2 to 4 mm is left between the compression plate and the movable plate.

3. A mold for preparing a resin triangular prism optical element according to claim 1, Its characteristics are The compression mechanism is provided with a compression ejector rod and a common ejector rod on the ejection mechanism, and a compression mold core is provided at the other end of the compression ejector rod.

4. A mold for preparing a resin triangular prism optical element according to claim 1, Its characteristics are The first punching position of the fixed mold and the movable mold are combined to form a first punching position cavity for injecting transparent materials, and the second punching position of the fixed mold and the movable mold are combined to form a second punching position cavity for injecting black materials.

5. A mold for preparing a resin triangular prism optical element according to claim 1, Its characteristics are The shapes of the No. 1 mold and the No. 2 mold of the movable mold are exactly the same, and the shapes of the first punching position and the second punching position of the fixed mold are different.

6. A mold for preparing a resin triangular prism optical element according to claim 1, Its characteristics are A 100mm heat insulation gap is provided between the first striking position and the last striking position of the fixed mold.

7. A mold for preparing a resin triangular prism optical element according to claim 1, Its characteristics are The mold is provided with a central rotation axis, and the first mold and the second mold of the movable mold are centrally symmetrical with respect to the rotation axis.

8. A method for preparing a prism according to any one of claims 1 to 7, wherein the method comprises: Its characteristics are The following steps are involved: (1). The movable platen of mold No. 1 is in the first working position, and together with the fixed platen of the first working position, it forms the first working position cavity. The movable platen of mold No. 2 is in the second working position, and together with the fixed platen of the second working position, it forms the second working position cavity. The barrel of the first working position is made of transparent material, and the barrel of the second working position is made of black material. (2) Adjust the clamping force of the two-color injection molding machine with mold clamping compression function. When the mold is manually closed with this clamping force, the mold should be closed to the bottom and the compression gap spacing should be 0; (3) Set the clamping force of the injection molding machine in compression standby mode to 1 / 3 of the normal clamping force. In this way, the fully automatic start will leave a compression gap of 0.1 to 0.2 mm between the compression mechanism and the movable platen, and the resin material will be injected into the corresponding cavity through the corresponding mold gate sleeve and station hot nozzle; (4) When the cavity is filled to more than 99% and the pressure is switched to hold, the clamping part of the injection molding machine starts to switch to the first stage of compression mode: expansion. A smaller compression force is used first. At this time, as the cavity is gradually filled, the pressure in the mold gradually increases, exceeding the clamping force, and the pressure is transmitted to the compression mechanism through the compression mold core, driving the compression mechanism to retreat. The compression gap between the compression mechanism and the moving template will gradually expand to 0.2-0.3 mm. (5) Entering the second stage of compression mode: compression, the clamping part of the injection molding machine gradually increases the clamping force, gradually exceeds the cavity pressure, and then drives the compression mechanism forward, the compression gap is reduced, and the compression mold core uniformly compresses and thins the product, until the compression gap is reduced to close to 0; (6). After cooling for a period of time, the mold is opened again, and then the movable mold side is rotated 180°. The movable mold plate of mold No. 1 is rotated to the rear punching position. The product that has been punched out in mold No. 1 and the fixed mold plate of the rear punching position form the cavity of the rear punching position. The movable mold plate of mold No. 2 is rotated to the first punching position and forms the cavity of the first punching position with the fixed mold plate of the first punching position. (7) The back working station starts to inject black material, while the front working station starts to inject transparent material; (8). After cooling, the mold is opened, the ejection mechanism at the rear working position moves forward, and the ejector rod is driven forward to eject the product; (9). The movable mold rotates 180° again to start the next cycle.

9. A mold for preparing a resin prism optical element, Its characteristics are A monochrome prism injection mold comprises a fixed mold and a movable mold, wherein the fixed mold further comprises a fixed mold seat plate, a hot runner plate and a fixed mold plate, and the movable mold further comprises a movable mold seat plate, an ejection mechanism, a compression plate and a movable mold plate; the fixed mold seat plate is arranged above the hot runner plate, a hot nozzle and a valve needle are arranged in the hot runner plate, the fixed mold plate is arranged below the hot runner plate, and the valve needle and the hot nozzle penetrate the hot runner plate and the fixed mold plate; the movable mold plate is arranged above the compression plate, and the movable mold plate and the fixed mold plate are combined to form a product cavity, the area in the cavity that needs to be matted is the cavity leather grain / frosted area, the compression plate is located below the movable mold plate, a compression spring is arranged in the compression plate, the ejection mechanism is arranged below the compression plate, and the movable mold seat plate is arranged below the ejection mechanism.

10. A method for preparing a prism using a mold for preparing a resin prism optical element according to claim 9, Its characteristic is that The mold corresponding to the area of ​​the product that needs matte treatment is treated with leather grain / frosted. The mold is installed in the clamping part of the injection molding machine and heated to meet the drying temperature and time required by the resin material. Then the cycle starts. The clamping force of the injection molding machine is set to 1 / 3 of the normal clamping force of the product. After the mold is closed, the injection part of the injection molding machine injects the molten resin into the mold. After the resin fills 99% of the cavity, the injection part of the injection molding machine switches to pressure holding. At the same time or 1 to 2 seconds later, the clamping part also gradually increases the pressure until the normal clamping force required by the product is reached, and the product is compressed with a compression range of 0.1 to 0.2 mm. Under sufficient holding and compression pressure, the resin will effectively copy the shape of the mold surface, including the light-transmitting area and the leather grain / frosted area. After cooling, the solidified product has the shape designed by the mold, including the light-transmitting area and the leather grain / frosted area that needs to be matte.

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