CN109397611B

CN109397611B - Fresnel lens manufacturing method, injection molding die device used by same and manufactured Fresnel lens

Info

Publication number: CN109397611B
Application number: CN201710712528.5A
Authority: CN
Inventors: 游鸿文
Original assignee: Shuangying Technology Co ltd
Current assignee: Dongguan Shuangying Optoelectronic Technology Co.,Ltd.
Priority date: 2017-08-18
Filing date: 2017-08-18
Publication date: 2022-02-11
Anticipated expiration: 2037-08-18
Also published as: CN109397611A

Abstract

The invention discloses a manufacturing method of a Fresnel lens, an injection molding die device used by the manufacturing method and the manufactured Fresnel lens. The manufacturing method comprises the following steps: the method comprises a rapid heating step, an injection step, a transfer printing step and a rapid cooling forming step. The rapid heating step comprises the step of injecting high-heat fluid into at least one mold water path in the Fresnel lens injection molding mold device so as to rapidly heat the Fresnel lens to the temperature at which the thermoplastic plastic material can flow. The rapid cooling molding step is to inject low-temperature fluid into a mold waterway in the injection molding mold device so as to rapidly cool the liquid thermoplastic material in the mold cavity and cool and solidify the liquid thermoplastic material to form the Fresnel lens. The mold water path can ensure that the injection molding mold device can be uniformly and rapidly heated and cooled, and local cooling and solidification of plastic materials are avoided, so that the optical quality of the Fresnel lens is improved.

Description

Fresnel lens manufacturing method, injection molding die device used by same and manufactured Fresnel lens

Technical Field

The present invention relates to a method for manufacturing a fresnel lens, an injection molding die apparatus used in the method, and a fresnel lens manufactured by the method, and more particularly, to a method for manufacturing a fresnel lens, an injection molding die apparatus used in the method, and a fresnel lens manufactured by the apparatus.

Background

Fresnel lenses, also known as screw lenses, are characterized by their optical properties of short focal length, being more material-saving and lighter than conventional lenses. The fresnel lens is thinner than earlier lens designs and therefore delivers more light, and therefore the light source is more efficient in directing light farther away after being refracted through the fresnel lens.

Fresnel lenses are widely used in lighthouse projection navigation lights, lenses for projection film projectors, screens for rear projection displays, and headlights of automobiles, and are the most widely used lenses.

Most optical lenses are manufactured by injection molding with a mold, and conventional fresnel lenses are mainly manufactured by this method, and in general, the fresnel lenses are formed by processing thermoplastic plastic by an injection molding machine. However, in the existing fresnel lens mold, the temperature rise of the mold is slow, and the temperature of each part of the mold is uneven, so that the flow speed of the thermoplastic plastic in the mold cavity is different, and thus the molding cycle is too long, which causes the surface of the fresnel lens to be easily subjected to defect flow marks and air lines during the injection molding process, and finally the surface of the fresnel lens cannot achieve the effect of a sufficiently high light mirror surface. In addition, because of the temperature unevenness of each part of the mold during processing, the plastic material with lower temperature is cooled and formed in advance, so that Short Shot (Short Shot) defects are generated at the sharp parts of the fresnel lens, and the interior of the fresnel lens containing the Short Shot defects is accompanied with the problem of stress concentration, thereby further influencing optical imaging and seriously influencing the quality of the fresnel lens.

Referring to fig. 18, fig. 18 shows a conventional fresnel lens 90 with short-shot defects, in which the tips 91 of the saw teeth and the grooves 92 between adjacent saw teeth are not perfectly sharp but have rounded blunt shapes under an electron microscope with 15 times optical magnification due to insufficient filling of the plastic material.

Up to now, there has been no method for manufacturing serrations and grooves of fresnel lenses having a sharp shape under an electron microscope with an optical magnification of more than 15 times.

Disclosure of Invention

The inventor of the present invention has developed a method for manufacturing a fresnel lens, an injection molding mold device used in the manufacturing process, and a fresnel lens manufactured by the method, in view of the disadvantages that the local filling of the cavity is insufficient due to the uneven cooling and heating of each part of the mold during the injection molding process, and the sharpness of the sawtooth part of the finished fresnel lens is insufficient, thereby affecting the optical quality.

The invention mainly aims to provide a manufacturing method of a Fresnel lens, an injection molding die device used by the manufacturing method and the Fresnel lens manufactured by the manufacturing method. The manufacturing method is characterized in that the plastic material can be fully filled into a cavity in a die by carrying out a rapid cooling and rapid heating treatment step on the thermoplastic plastic material, so that the manufactured Fresnel lens generates a sufficiently sharp structure on the sharp ends of the saw tooth parts and in the grooves, and the surface of the Fresnel lens has the effect of a high-light mirror surface, thereby improving the optical quality of the Fresnel lens.

In order to achieve the above object, the method for manufacturing a fresnel lens using a sharp cooling and heating mold core of the present invention comprises the following steps:

a rapid heating step, injecting high heat fluid into at least one mold waterway in the Fresnel lens injection molding mold device to rapidly heat to the temperature at which the thermoplastic plastic material can flow;

an injection step of injecting a liquid thermoplastic material into a mold cavity in the Fresnel lens injection molding mold device;

a transfer printing step, pressurizing the liquid thermoplastic plastic material in the mold cavity by using at least one pair of mold cores so as to enable the thermoplastic plastic material to generate a Fresnel lens structure; and

and a rapid cooling molding step, namely injecting low-temperature fluid into a mold water path in the Fresnel lens injection molding mold device to rapidly cool the liquid thermoplastic material in the mold cavity and cool and solidify the liquid thermoplastic material to form the Fresnel lens.

The Fresnel lens injection molding mold device and the related manufacturing method adopt the first mold waterway and the second mold waterway to inject hot steam, hot water or cold water into the first mold waterway and the second mold waterway so as to rapidly and uniformly heat or cool the female mold and the male mold, so that the temperature of each part of the plastic material in the mold cavity is rapidly, uniformly and uniformly raised and lowered, the surface of the Fresnel lens is prevented from generating defect flow marks and air lines due to overlong injection molding process time, in addition, the uniform temperature control can prevent the thermoplastic material part from being cooled and solidified in advance to cause short shot phenomenon, and the sharpness of the sharp part of the Fresnel lens can be improved, thereby improving the optical quality of the Fresnel lens.

In an embodiment of the invention, the mold water path is a first mold water path in a female mold of the fresnel lens injection molding mold device.

In an embodiment of the invention, the mold water path is a second mold water path in a male mold of the fresnel lens injection molding mold apparatus.

In an embodiment of the invention, the mold water path refers to a first mold water path in a female mold and a second mold water path in a male mold of the fresnel lens injection molding mold device.

In an embodiment of the present invention, in the rapid heating step, a rapid heating and cooling mold temperature controller is used to input high-temperature steam into the mold water path for rapid heating.

In an embodiment of the present invention, in the rapid cooling and forming step, a rapid cooling and heating mold temperature controller is used to input low temperature water into the mold water path for rapid cooling.

In an embodiment of the invention, in the injecting step, a plastic injection molding machine is used to inject plastic into the fresnel lens injection molding device.

Another objective of the present invention is to provide a fresnel lens injection molding die apparatus suitable for the above manufacturing method, which includes:

the first assembling groove is formed in the female die, a first die water channel is formed in the female die, and a first die cavity communicated with the first assembling groove is formed in one surface of the female die;

a male mold, which is connected with the female mold and can move relative to the female mold to be close to or far away from the female mold, at least one second assembly groove aligned and matched with the corresponding first assembly groove is formed on the male mold, a second mold cavity communicated with the second assembly groove is formed on one surface of the male mold, and the second mold cavity and the first mold cavity jointly form a mold cavity;

at least one cavity insert which is respectively arranged in the corresponding first assembling grooves; and

at least one male mold core is respectively arranged in the corresponding second assembling grooves and matched with the female mold core.

In an embodiment of the present invention, a second mold waterway is formed in the male mold.

In an embodiment of the invention, the first mold waterway and the second mold waterway are criss-cross.

In an embodiment of the invention, the female mold has a female mold pad and a female mold frame, at least one of the first assembling groove, the first mold waterway and the first mold cavity is formed in the female mold pad, and the female mold frame is hollow and is sleeved on the female mold pad.

In an embodiment of the invention, the male mold has a male mold lining block and a male mold outer frame, at least one of the second assembly groove, the second mold waterway and the second mold cavity is formed in the male mold lining block, and the male mold outer frame is hollow and is sleeved on the male mold lining block.

In an embodiment of the invention, the first assembling grooves are plural, and the cavity insert is plural; the first mold cavity is provided with a first main plastic runner and a plurality of first branch plastic runners, and the plurality of first branch plastic runners extend outwards from the first main plastic runner and are respectively communicated with the plurality of first assembling grooves.

In an embodiment of the invention, the second assembling grooves are plural, and the core insert is plural; the second mold cavity is provided with a second main plastic runner and a plurality of second branch plastic runners, the second main plastic runner corresponds to the first main plastic runner, the plurality of second branch plastic runners respectively correspond to the plurality of first branch plastic runners, extend outwards from the second main plastic runner and are respectively communicated with the plurality of second assembly grooves.

In an embodiment of the invention, two opposite vertexes of the first mold water path are two first confluence points, and each first confluence point forms a first main branch passage which extends to the outside of the master mold pad.

In an embodiment of the invention, two first sub-branch passages are formed at each first confluence point of the first mold water passage, and the two first sub-branch passages extend to the outside of the master mold pad.

In an embodiment of the invention, two opposite vertexes of the second mold water path are two second confluence points, and each second confluence point forms a second main branch passage which extends to the outside of the male mold pad.

In an embodiment of the invention, two second sub-branch passages are formed at each second confluence point of the second mold water channel, and the two second sub-branch passages extend to the outside of the male mold pad.

In an embodiment of the invention, a first fresnel-structure rotating surface is formed on an inner side surface of the cavity, and a second fresnel-structure rotating surface is formed on an inner side surface of the core.

In an embodiment of the present invention, a first cavity water path is formed inside the cavity.

In an embodiment of the present invention, a second cavity water path is formed inside the core.

In an embodiment of the invention, two opposite vertexes of the first cavity water path of the cavity are two first connection points, and two first yielding through holes are formed through a first sealing gasket disposed on the cavity and respectively connected to the two first connection points.

In an embodiment of the invention, two opposite vertexes of the second cavity water path of the core are two second communication points, and a second gasket disposed on the core is penetrated to form two second yielding through holes respectively connected to the two second communication points.

In an embodiment of the invention, the fresnel lens injection molding mold device further includes a fixed substrate and a movable substrate, the fixed substrate and the female mold are fixed to each other, the fixed substrate is provided with at least one first mold core pipeline set, each first mold core pipeline set has a first inflow pipe and a first outflow pipe to be respectively connected to two first yielding through holes of the corresponding female mold core; the movable base plate and the male die are fixed with each other, at least one second die core pipeline set is arranged on the movable base plate, and each second die core pipeline set is provided with a second inflow pipe and a second outflow pipe which are respectively connected to two second abdicating through holes of the corresponding male die core.

Still another object of the present invention is to provide a fresnel lens manufactured by the above manufacturing method, including:

the Fresnel lens comprises a lens body and a plurality of concentric annular ribs, wherein the concentric annular ribs are formed on the lens body and are arranged in a concentric circle mode, on a side cross section passing through a central shaft of the Fresnel lens, the concentric annular ribs respectively have sawtooth cross sections, and the sawtooth cross sections are in a left-right symmetrical shape based on the central shaft;

wherein the tips of the saw-tooth cross-sections of the concentric annular ribs appear sharp instead of rounded under observation under a microscope at a magnification of up to 150.

In an embodiment of the present invention, a saw tooth groove section is formed between any two adjacent saw tooth sections, and the bottom of the saw tooth groove section is sharp rather than rounded under the observation of a microscope with a magnification of up to 150.

The manufacturing method of the invention can fully fill the plastic material into the cavity in the die by carrying out the treatment steps of rapid cooling and rapid heating on the thermoplastic plastic material, thereby leading the manufactured Fresnel lens to generate a sufficiently sharp structure on the sharp end of the sawtooth part and in the groove, leading the surface of the Fresnel lens to have the effect of a high light mirror surface and further improving the optical quality of the Fresnel lens.

Drawings

Fig. 1 is a perspective view of a fresnel lens injection molding die apparatus according to the present invention.

Fig. 2 is a sectional view of a fresnel lens injection molding die apparatus according to the present invention.

Fig. 3 is a three-dimensional exploded view of the female mold, the female mold insert, the male mold and the male mold insert of the fresnel lens injection molding mold device according to the present invention.

Fig. 4 is an exploded perspective view of a master mold pad and a master mold core in the fresnel lens injection molding mold apparatus of the present invention.

Fig. 5 is an exploded perspective view of a cavity insert of the fresnel lens injection molding apparatus of the present invention.

Fig. 6 is an exploded perspective view of a core insert and a core insert in the fresnel lens injection molding apparatus of the present invention.

Fig. 7 is an exploded perspective view of a core insert in the fresnel lens injection molding apparatus of the present invention.

Fig. 8 is a perspective view of the plastic material in the cavity of the fresnel lens injection molding die apparatus according to the present invention.

Fig. 9 is a schematic plan view of a master mold pad in the fresnel lens injection molding apparatus according to the present invention.

Fig. 10 is a schematic plan view of a male mold pad in the fresnel lens injection molding apparatus according to the present invention.

Fig. 11 is a schematic plan view of a cavity insert in the fresnel lens injection molding apparatus according to the present invention.

Fig. 12 is a schematic plan view of a core insert and a waterway of an internal mold in the fresnel lens injection molding mold device according to the present invention.

Fig. 13 is a perspective view of the mold water path and the mold core pipe set along the overlapping direction of the female mold and the male mold in the fresnel lens injection molding mold device according to the present invention.

Fig. 14 is a cross-sectional view of a fresnel lens of the present invention taken along a central axis.

Fig. 15 is a schematic enlarged cross-sectional view of a fresnel lens of the present invention under an electron microscope at 150 x optical magnification.

Fig. 16 is a block diagram of a fresnel lens injection molding mold apparatus, a rapid cooling and heating mold temperature controller, and a plastic injection molding machine according to the present invention.

FIG. 17 is a flowchart illustrating steps of a method for manufacturing a Fresnel lens according to the present invention.

Fig. 18 is a schematic enlarged cross-sectional view of a conventional fresnel lens under an electron microscope at 15 times optical magnification.

[ notation ] to show

1 Fresnel lens ejection forming die device

2 temperature controller for rapid cooling and heating mould

3 plastic injection molding machine

10 female die and 11 female die outer frames

13 master mold pad 130 first assembly groove

135 first mould water path 1350 first confluence point

1351 first main branch path 1352 first sub branch path

136 first main plastic runner 137 first branch plastic runner

20 male die and 21 male die outer frame

23 male mold backing block 230 second assembly groove

235 second mold waterway 2350 second confluence point

2351 second main branch path 2352 second secondary branch path

30 cavity 300 first fresnel structure rotating surface

301

first gasket seal

31, 32 first abdicating through hole

35 first core water path 350 first connection point

40 core 400 second fresnel structure surface of revolution

401 second sealing gasket 41, 42 second abdicating through hole

45 second cavity waterway 450 second connection point

50 fixed base plate 51 first inflow pipe

52 first outflow pipe

60 second inflow pipe of movable substrate 61

62 second outflow pipe

80 Fresnel lens 80a Fresnel lens Plastic section

81 saw tooth lug section 811 tip

82 saw tooth groove cross section 821 bottom

C36 Main Plastic runner C37 Branch Plastic runner

90 conventional fresnel lens 91 tip

92 groove

Detailed description of the invention

The invention will be further described with reference to specific embodiments, and the advantages and features of the invention will become apparent as the description proceeds. These examples are illustrative only and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention.

Referring to fig. 1 to 3 and fig. 16, a fresnel lens injection molding mold apparatus 1 of the present invention can be connected to a rapid cooling and heating mold temperature controller 2 and a plastic injection molding machine 3, and includes: a female mold 10, a male mold 20, at least one female mold insert 30, at least one male mold insert 40, a fixed base plate 50, and a movable base plate 60.

Referring to fig. 4 and 9, at least one first assembly groove 130 is formed on the female mold 10, and a first mold water passage 135 is formed in the female mold 10 for injecting hot steam, hot water or cold water injected by the rapid cooling and rapid heating mold temperature controller 2, so as to rapidly and uniformly heat or cool the female mold 10. The first mold waterway 135 may be quadrilateral, spiral, U-shaped, or any shape that may be uniformly distributed within the master mold 10. The high-temperature hot steam can have a high temperature of 140 to 160 ℃, so that the good fluidity of the common thermoplastic plastic material can be maintained at the high temperature, and the temperature of the hot steam can be increased according to the condition; in addition, the temperature of the cold water can be 80 to 90 ℃, at which the common thermoplastic material can be cooled and solidified, and the temperature of the cold water can be increased or decreased according to the condition. A first cavity communicating with the first assembling groove 130 is formed on one side of the female mold 10 for the injection molding machine 3 to inject the thermoplastic material therein. In addition, the temperature of the thermoplastic material of the plastic injection molding machine 3 during the injection (also referred to as the material temperature) is typically 200 to 260 ℃.

In the preferred embodiment, the female mold 10 has a female mold pad 13 and a female mold frame 11, at least one of the first assembly groove 130, the first mold water passage 135 and the first mold cavity is formed in the female mold pad 13, and the female mold frame 11 is hollow and is disposed on the female mold pad 13. The opposing vertices of the first mold waterway 135 are two first confluence points 1350, and each of the first confluence points 1350 forms a first main branch passage 1351, the first main branch passage 1351 extending beyond the master pad 13. In addition, two first sub-branch passages 1352 are formed in each first confluence point 1350, and the two first sub-branch passages 1352 extend to the outside of the master pad 13. The first main branch passage 1351 may be connected to a line from the rapid cooling and heating mold temperature controller 2 for injecting hot steam, hot water or cold water into the master mold pad 13. The first secondary branch passageways 1352 may be screwed to seal off external lines and may be connected to the temperature controller 2 from the chill and hot die in other situations.

Referring to fig. 6, 10 and 13, the male mold 20 and the female mold 10 are connected to each other and can move relative to the female mold 10 to abut against or move away from the female mold 10. A second mold water path 235 is formed in the male mold 20 for injecting hot steam, hot water or cold water injected by the rapid cooling and rapid heating mold temperature controller 2 therein, thereby rapidly and uniformly heating or cooling the male mold 20. The second mold waterway 235 may be quadrilateral, spiral, U-shaped, or any shape that may be uniformly distributed within the male mold 20. The second mold waterway 235 may be crosswise to the first mold waterway 135, as shown in fig. 13. At least one second assembling groove 230 aligned and matched with the corresponding first assembling groove 130 is formed on the male mold 20, and a second mold cavity communicated with the second assembling groove 230 is formed on one surface of the male mold 20 for the injection molding machine 3 to inject the thermoplastic plastic material therein. The second mold cavity and the first mold cavity together form a mold cavity.

In the preferred embodiment, the male mold 20 has a male mold pad 23 and a male mold housing 21, at least one of the second assembly groove 230, the second mold waterway 235 and the second mold cavity is formed in the male mold pad 23, and the male mold housing 21 is hollow and is disposed on the male mold pad 23. The two opposite vertices of the second mold waterway 235 are two second confluence points 2350, each second confluence point 2350 forming a second main branch passage 2351, the second main branch passage 2351 extending beyond the male mold pad 23. In addition, a second subsidiary branch passage 2352 is formed at each second confluence point 2350 of the second mold waterway 235, and the second subsidiary branch passages 2352 extend beyond the male mold pad 23. The second main branch passage 2351 may be connected with a line from the rapid cooling and heating mold temperature controller 2 for injecting hot steam, hot water or cold water into the male mold pad 23. The second secondary branch passageways 2352 may be screwed for sealing, not otherwise connected to external piping, or may be connected to the temperature controller 2 from the rapid thermal quenching die in other situations.

Referring to fig. 4, 5 and 11, the cavity insert 30 is disposed in the corresponding first assembling groove 130. A first mold core water path 35 is formed inside the cavity core 30 for injecting hot steam, hot water or cold water injected by the rapid cooling and rapid heating mold temperature controller 2, so as to rapidly and uniformly heat or cool the cavity core 30. The first mold core waterway 35 may be a quadrangle, a spiral, a U-shape, or any shape that may be uniformly distributed in the cavity 30. Two opposite vertexes of the first cavity water path 35 are two first communication points 350, two first yielding through

holes

31, 32 are formed on a first sealing gasket 301 disposed on the cavity 30, and the two first yielding through

holes

31, 32 are respectively connected to the two first communication points 350. In addition, a first fresnel structure rotation surface 300, which may be aspheric, is formed on an inner side surface of the cavity 30. In addition, two bolts may be disposed on the cavity 30 to further fix the first sealing gasket 301 on the cavity 30.

Referring to fig. 6, 7 and 12, the core insert 40 is disposed in the corresponding second assembling groove 230 and matched with the cavity insert 30. A second cavity water channel 45 is formed inside the core 40 for injecting hot steam, hot water or cold water injected by the rapid cooling and rapid heating mold temperature controller 2, so as to rapidly and uniformly heat or cool the core 40. The second core waterway 45 may be a quadrilateral, spiral, U-shaped, or any shape that may be uniformly distributed within the core 40. Two opposite vertexes of the second cavity water path 45 of the core 40 are two second communication points 450, two second yielding through holes 41, 42 are formed through a second sealing gasket 401 disposed on the core 40, and the two second yielding through holes 41, 42 are respectively connected to the two second communication points 450. In addition, a second fresnel structure rotation surface 400 is formed on an inner side surface of the core insert 40. The fresnel lens can be manufactured by embossing the first fresnel-structure rotating surface 300 and the second fresnel-structure rotating surface 400 onto the thermoplastic material surface in the mold cavity, respectively. In addition, two bolts may be disposed on the core insert 40 to further fix the second sealing gasket 401 on the core insert 40.

Referring to fig. 4, 6 and 8, in the preferred embodiment of the present invention, there are a plurality of first assembling grooves 130 and a plurality of cavity inserts 30; the first mold cavity has a first main plastic runner 136 and a plurality of first branch plastic runners 137, and the plurality of first branch plastic runners 137 extend outward from the first main plastic runner 136 and are respectively communicated with the plurality of first assembling grooves 130. In addition, there are a plurality of second assembling grooves 230, and a plurality of core inserts 40; the second mold cavity has a second main plastic runner 236 and a plurality of second branch plastic runners 237, the second main plastic runner 236 corresponds to the first main plastic runner 136, the plurality of second branch plastic runners 237 respectively correspond to the plurality of first branch plastic runners 137, and extend outward from the second main plastic runner 236 and respectively communicate with the plurality of second assembling grooves 230. By arranging the plurality of female molds 30 and male molds 40, the fresnel lens injection molding mold apparatus 1 can manufacture a plurality of fresnel lenses in a single processing procedure. The distribution of the plastic in the mold cavity is shown in fig. 8, which shows a main plastic runner C36, a plurality of branch plastic runners C37 connected to the main plastic runner C36, and a plurality of fresnel lens plastic portions 80a located at the branch plastic runners. Hot water vapor, hot water or cold water is injected into the first mold water passage 135 and the second mold water passage 235 to uniformly cool and rapidly heat the female mold 10 and the male mold 20, so that the temperatures of the main plastic passage part C36, the branch plastic passage part C37 and the fresnel lens plastic part 80a can be uniformly raised and lowered, and the problem that the optical quality of the fresnel lens is reduced due to poor molding caused by over-low temperature of local plastic materials and solidification of the fresnel lens is avoided.

The fixed substrate 50 and the female mold 10 are fixed to each other, at least one first mold core pipeline set is disposed on the fixed substrate 50, and each first mold core pipeline set has a first inflow pipe 51 and a first outflow pipe 52 to be connected to two first yielding through

holes

31 and 32 of the corresponding female mold core 30, respectively. The first inflow pipe 51 and the first outflow pipe 52 may be connected to the rapid cooling and heating mold temperature controller 2, thereby injecting hot steam, hot water or cold water into the cavity insert 30.

The movable substrate 60 and the male mold 20 are fixed to each other, at least one second mold core pipe set is disposed on the movable substrate 60, and each second mold core pipe set has a second inflow pipe 61 and a second outflow pipe 62 to be connected to the two second abdicating through holes 41 and 42 of the corresponding male mold core 40, respectively. The second inflow pipe 61 and the second outflow pipe 62 may be connected to the rapid cooling and heating mold temperature controller 2, thereby injecting hot steam, hot water or cold water into the core insert 40.

Referring to fig. 1, 16 and 17, the method for manufacturing the fresnel lens using the fresnel lens injection molding mold apparatus 1 of the present invention includes: a rapid heating step S01, an injection step S02, a transfer step S03 and a rapid cooling forming step S04.

The rapid heating step S01 includes injecting a high heat fluid into at least one mold water path in the fresnel lens injection molding mold apparatus 1 to rapidly heat the mold to a temperature at which the thermoplastic material can flow. The at least one mold waterway may be the first mold waterway 135 alone in the female mold 10, the second mold waterway 235 alone in the male mold 20, or both the first mold waterway 135 and the second mold waterway 235. In the rapid heating step S01, the mold water path is supplied with high-temperature steam to perform rapid heating by the rapid cooling and rapid heating mold temperature controller 2.

The injection step S02 includes injecting a liquid thermoplastic material into a cavity in the fresnel lens injection molding apparatus 1. In the injection step S02, the thermoplastic plastic is injected into the fresnel lens injection molding die set 1 by the plastic injection molding machine 3.

The transferring step S03 includes pressing the liquid thermoplastic material in the mold cavity with at least one pair of mold cores to generate fresnel lens structures in the thermoplastic material.

The rapid cooling molding step S04 includes injecting a low-temperature fluid into the mold core water path in the fresnel lens injection molding mold device 1 to rapidly cool the liquid thermoplastic material in the mold cavity and solidify the liquid thermoplastic material to form the fresnel lens. In the rapid cooling step S04, the mold core is quenched by inputting low-temperature water into the mold core water path through the rapid cooling and rapid heating mold temperature controller 2.

Referring to fig. 14 and 15, the fresnel lens 80 manufactured by the manufacturing method of the present invention includes: the Fresnel lens comprises a lens body and a plurality of concentric annular rib parts, wherein the concentric annular rib parts are formed on the lens body and are arranged in a concentric circle mode, on the side section passing through the central axis of the Fresnel lens, the concentric annular rib parts are respectively in sawtooth bump sections 81, the sawtooth bump sections 81 are distributed in a left-right symmetrical mode by taking the central axis as a reference, and a sawtooth groove section 82 is arranged between any two adjacent sawtooth bump sections 81.

Under observation with a microscope at a magnification of up to 150, the tip 811 of the saw tooth bump section 81 of each concentric annular rib portion assumes a sharp shape instead of a rounded corner, and the bottom 821 of each saw tooth groove section 82 assumes a sharp shape instead of a rounded corner.

The invention has the following advantages:

1. the fresnel lens injection molding mold device 1 and the related manufacturing method of the fresnel lens of the present invention employ the first mold waterway 135 and the second mold waterway 235 to inject hot steam, hot water or cold water into them, so as to heat or cool the female mold 10 and the male mold 20 rapidly and uniformly, so that the temperature of each part of the plastic material in the mold cavity is raised and lowered rapidly, uniformly and uniformly, thereby avoiding the surface of the fresnel lens from generating defect flow marks and air marks due to too long time of the injection molding process, and in addition, uniform temperature control can avoid the short shot phenomenon due to the prior cooling and solidification of the thermoplastic material part, thereby improving the sharpness of the sharp part of the fresnel lens, and further improving the optical quality of the fresnel lens, as shown in fig. 15.

2. The first mold water path 135 and the second mold water path 235 of the male mold 20 and the female mold 10 are configured in a cross manner, so that the uniform temperature control performance of the female mold 10 and the male mold 20 is further improved, and the quality of the finished fresnel lens is improved.

Claims

1. A method of manufacturing a fresnel lens, comprising:

a rapid cooling molding step, in which low-temperature fluid is injected into a mold core water path in the Fresnel lens injection molding mold device to rapidly cool the liquid thermoplastic material in the mold cavity and cool and solidify the liquid thermoplastic material to form the Fresnel lens; wherein this fresnel lens jets out forming die device and includes:

the female die is provided with at least one first assembling groove penetrating through the female die, a first die water channel is formed in the female die, and a first die cavity communicated with the first assembling groove is formed on one surface of the female die;

the male die is connected with the female die and can move relative to the female die to be close to or far away from the female die, the male die is provided with at least one second assembling groove which penetrates through the male die and is aligned and matched with the corresponding first assembling groove, a second die cavity communicated with the second assembling groove is formed on one surface of the male die, and the second die cavity and the first die cavity jointly form a die cavity;

at least one male mold core is respectively arranged in the corresponding second assembling grooves and matched with the female mold core, a first mold core water path is formed inside the female mold core, and a second mold core water path is formed inside the male mold core.

2. The method of claim 1, wherein the rapid heating step is performed by supplying high-temperature steam to the mold water path through a rapid cooling and rapid heating mold temperature controller.

3. The method of claim 1, wherein the rapid cooling step is performed by introducing low temperature water into the mold water path through a rapid cooling/heating mold temperature controller.

4. The manufacturing method according to claim 1, wherein in the injection step, the plastic is injected into the fresnel lens injection molding die device by a plastic injection molding machine.

5. The method of claim 1, wherein the male mold has a second mold waterway formed therein.

6. The method of claim 5, wherein the first mold waterway and the second mold waterway are criss-crossed.

7. The method of claim 5, wherein the female mold has a female mold pad and a female mold frame, at least the first assembly groove, the first mold waterway and the first mold cavity being formed in the female mold pad, the female mold frame being hollow and fitting over the female mold pad.

8. The method of claim 5, wherein the male mold has a male mold liner block and a male mold chase, at least one of the second assembly groove, the second mold waterway, and the second cavity being formed in the male mold liner block, the male mold chase being hollow and fitting over the male mold liner block.

9. The method according to claim 5, wherein the first assembling grooves are plural, and the cavity insert is plural; the first mold cavity is provided with a first main plastic runner and a plurality of first branch plastic runners, and the plurality of first branch plastic runners extend outwards from the first main plastic runner and are respectively communicated with the plurality of first assembling grooves.

10. The method of claim 9, wherein the second assembly grooves are plural, and the core insert is plural; the second mold cavity is provided with a second main plastic runner and a plurality of second branch plastic runners, the second main plastic runner corresponds to the first main plastic runner, the plurality of second branch plastic runners respectively correspond to the plurality of first branch plastic runners, extend outwards from the second main plastic runner and are respectively communicated with the plurality of second assembly grooves.

11. The method of claim 7, wherein the opposing vertices of the first mold waterway are two first confluence points, each first confluence point defining a first main branch passageway extending beyond the master pad.

12. The manufacturing method according to claim 11, wherein two first sub branch passages are formed at each first confluence point of the first mold water path, the two first sub branch passages extending to the outside of the master mold pad.

13. The method of claim 8, wherein the second mold passageway has two opposing vertices defined by two second confluence points, each second confluence point defining a second main branch passageway extending beyond the male mold pad.

14. The manufacturing method according to claim 13, wherein a second sub-branch passage is formed at each second confluence point of the second mold water path, the second sub-branch passages extending beyond the male mold pad.

15. The method according to claim 1, wherein a first fresnel structure-rotated surface is formed on an inner surface of the cavity and a second fresnel structure-rotated surface is formed on an inner surface of the core.

16. The method of claim 1, wherein two opposite vertices of the first cavity waterway of the cavity are two first connection points, and a first gasket disposed on the cavity is penetrated to form two first abdication through holes, and the two first abdication through holes are respectively connected to the two first connection points.

17. The method of claim 16, wherein two opposite vertices of the second cavity waterway of the core are two second connection points, and a second gasket disposed on the core is penetrated to form two second abdication through holes respectively connecting the two second connection points.

18. The method according to claim 17, wherein the fresnel lens injection molding mold device further comprises a fixed substrate and a movable substrate, the fixed substrate and the female mold are fixed to each other, at least one first mold core tube set is disposed on the fixed substrate, each first mold core tube set has a first inflow tube and a first outflow tube for connecting to two first yielding through holes of the corresponding female mold core, respectively; the movable base plate and the male die are fixed with each other, at least one second die core pipeline set is arranged on the movable base plate, and each second die core pipeline set is provided with a second inflow pipe and a second outflow pipe which are respectively connected to two second abdicating through holes of the corresponding male die core.

19. A fresnel lens produced by the production method according to claim 1, comprising:

20. A fresnel lens according to claim 19 wherein between any two adjacent saw tooth sections there is a saw tooth groove section, the bottom of which appears sharp rather than rounded under observation under a microscope at a magnification of up to 150.