JPH079509A - Mold release method and device of lens made of plastic - Google Patents

Abstract

PURPOSE:To provide a mold release method of a plastic lens which can be released reliably and swiftly by neither requiring any skill for an operator nor imparting any injury to the lens and mold even if the plastic lens is combined parts of the lens and mold wherein the lens L is stuck firmly to the mold. CONSTITUTION:In a mold releasing method, high pressure water having hydraulic pressure of 80-300kg/cm<2> is infected through nozzles 23a, 23b of a high pressure water infecting device 40 to combined parts 6 of a lens and mold wherein after a polymerization process, a plastic lens is stuck firmly to the mold and integrated and the lens is separated from the mold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of releasing a plastic lens which is polymerized and molded in a mold and can be easily released from the mold by firmly adhering to the mold to form a solid lens.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 9, a polymerization molding process for a plastic lens has a concave and convex curved surface on both sides.
Inside, the glass molds 1 and 2 are provided with protrusions 3a having a width S.
It is inserted into a cylindrical plastic gasket 3 having a groove, and is fixed with clips 5 from both sides of the mold while maintaining a gap S between the molds, and then a thermosetting resin is injected into the gap S from an upper injection port 4. Then, after that, the molds 1 and 2, the gasket 3, and the entire injected resin are heated and polymerized to be molded.

The cured plastic lens L between the mold 1 and the mold 2 thus obtained has a preferable shape as a lens because both surfaces thereof are molded along the uneven curved surfaces of the molds 1 and 2. Although it has, a plastic lens L is produced by the above-mentioned polymerization molding process.
The molds 1 and 2 are firmly attached to both sides of the
The one in which the molds 1 and 2 and the gasket 3 are integrated is referred to as a lens type assembly 6. Therefore, even if the gasket 3 is removed, the plastic lens L cannot be easily released from the mold.

A conventional mold releasing method which has been carried out for such a lens type assembly 6 is disclosed in, for example, Japanese Patent Application Laid-Open No. 4-59314.
As a mold releasing method disclosed in Japanese Patent Laid-Open Publication No. JP-A No. 2004-32187, a mold releasing method by irradiating far infrared rays in a wavelength region in which the absorptance of a plastic lens is larger than that of a mold, Using a table and a blade, an operator fixes the lens mold assembly 6 to a vise, inserts the tip of the blade into the boundary surface between the lens L and the molds 1 and 2, and separates the two mold releasing methods, a plurality of lens molds Immerse the rack on which the assembly is placed in a warm water tank filled with warm water of about 80 ° C,
Immediately after that, a method of releasing the mold by a so-called heat shock method in which water or air is blown to be rapidly cooled.

[0005]

However, the mold releasing method of irradiating far infrared rays has an advantage of high productivity since a large number of lenses can be mold-released at once in the far infrared ray irradiating device. , In the case of a lens with a large thickness at the center than the thickness of the outer periphery, such as a convex lens with a high altitude, and the difference in thickness is large, part of the lens cannot be released because the bond between the mold and the lens is strong. There was a problem.

Further, in the method of releasing the lens from the mold with the vise and the blade, since a sharp blade must be directly inserted into the boundary surface between the lens and the mold to separate them, it is very difficult for the releasing work. However, unless the blade is accurately inserted into the boundary surface, the lens and the outer peripheral surface of the mold may be damaged or damaged, resulting in poor lens quality and yield. Moreover, there is a problem that the productivity is extremely low because the operator peels the lenses one by one from the lens-type assembly.

Further, in the above-mentioned mold releasing method using warm water, since the mold is immersed in a warm water tank and then rapidly cooled, there is a problem that a lens or a mold is cracked and cracked depending on the kind. A lens having a concave shape has a relatively weak adhesion to the mold and can be released by this method, which is put to practical use. However, there is a problem in that a lens having a convex shape and having a high number has a strong adhesion to the mold, and this method has a remarkably low success rate of releasing.

The present invention solves the above problems and, even in a lens type assembly in which the lens is firmly adhered to the mold, it is also very brittle and the lens has a thin wall and is very cracked. Even if it is an easy-to-use lens-type assembly, it does not require any skill for the operator, and does not damage the lens and the mold at all. It is intended to provide a mold release method.

[0009]

In order to achieve the above object, a method for releasing a plastic lens according to the present invention is
A thermosetting resin is injected into the gap of a mold having a fixed gap and solidified to mold a plastic lens, and then the mold and the lens of a lens type assembly in which the mold and the lens are integrated. 80 to the boundary
By injecting high-pressure water with a water pressure of 300 kg / cm ² ,
It is characterized in that the lens is released from the mold.

Also, in the plastic lens releasing apparatus according to the present invention according to the present invention, there is provided a table on which a lens mold assembly in which a mold and a lens are integrated is placed, and the lens mold assembly is the table. In a mold releasing device for a plastic lens, which has a holding means for holding above and a high-pressure water jetting means for jetting high-pressure water to the lens-type assembly, the pressure of the high-pressure water is set to 80 to 300 kg / cm ² of water pressure. The water pressure adjusting means for adjusting is provided.

That is, the success or failure of mold release of the plastic lens largely depends on the water pressure of the high-pressure water, and the lens and the mold are damaged, although it depends on the shape and material of the lens and the mold, the injection conditions of the high-pressure water, and the like. The above water pressure is necessary for surely releasing the mold without causing the problem. There are various types of lenses with various shapes and materials, and the adhesive strength with the mold is different. In order to reduce damage to the lens and the mold as much as possible, it is preferable to perform mold release with appropriate water pressure for each type of lens. As the water quality of the high-pressure water, it is preferable to use pure water having an electric conductivity of 1 to 50 μS / cm or less in order to prevent the plastic lens from being soiled. Not only pure water but also other fluids can be used,
It is preferable to use pure water of the above-mentioned water quality because it costs a lot.

Next to the water pressure, important factors affecting the success or failure of mold release are the flow rate of the high-pressure water to be jetted, the jetting angle thereof, and the preheating temperature of the lens-type assembly. First, at the same pressure, the flow rate of high-pressure water is primarily determined by the inner diameter of the injection port of the nozzle. Therefore, even if the water pressure is high, the inner diameter of the injection port of the nozzle to be used is small, and if the flow rate of the jet flow is small, it will not be released from the mold. Also, if the water pressure is low, it will not be released. Therefore, the most preferable inner diameter of the nozzle injection port is 0.3 to 1.5 mm. The jetting angle (jetting angle θ in FIG. 3) of the high-pressure water with respect to the lens type assembly is the tangent line (tangent lines L1 and L2 in FIG. 3) drawn to the boundary surface between the lens and the mold in the outer peripheral portion of the lens type assembly. -20 to 3
The angle of 0 ° is preferable. Where the injection angle θ
As for positive and negative, the positive takes the lens side with the tangent as a sakai, and the negative takes the mold side. When the injection angle θ exceeds the above range, the releasing force becomes insufficient and the releasing success rate is remarkably reduced. Moreover, an excessively large bending moment is locally applied to the mold or the lens at the time of releasing the lens or the mold. It is not preferable because the probability of breakage increases and the yield decreases. In addition, the lens type assembly is preliminarily 60 to 12
If preheated to 0 ° C., the adhesive force between the lens and the mold is reduced, so that the mold release of the lens becomes very easy. If the preheating temperature of the lens mold assembly is lower than 60 ° C, the plastic lens and the mold remain firmly adhered, and the force of the jet flow must be increased in order to release the plastic lens. The mold will be overloaded and the probability of breakage will increase. On the other hand, when the temperature exceeds 120 ° C., problems such as distortion of the plastic lens due to heating occur. Therefore, when the high-pressure water is sprayed on the boundary between the mold and the lens, the lens-type assembly is preheated to 60 to 120 ° C., and then the high-pressure water is applied to the boundary between the lens and the mold at the outer peripheral portion of the lens-type assembly. The inner diameter is 0.3 to 1.5 mm with respect to the tangent drawn on the surface
When the spraying is performed at a spraying angle of -20 to 30 ° from the spraying nozzle, the mold release is further promoted. The water temperature of the high-pressure water used for mold release can be in the range of about 10 to 95 ° C, but if the one heated to 60 to 95 ° C is used, it will not be affected by heat shock and will not be used during mold release. The crack occurrence rate of the lens and the mold can be significantly reduced, and the yield can be significantly improved.

At least one high-pressure water jet nozzle may be used, but it is preferable that a plurality of high-pressure water jet nozzles be arranged at the outer peripheral portion of the boundary with the mold or lens to jet high-pressure water simultaneously from a plurality of directions. That is, a thin plastic lens has low strength and is liable to be broken at the time of mold release. The mold is released from the outer periphery evenly and can be easily released without applying excessive force to the lens, so the yield is higher than the method of ejecting high pressure water from one direction with one nozzle. Become. In particular, for a very thin lens such as an aspherical convex lens having a non-uniform curvature, which has a diameter of about 80 mm and a peripheral wall thickness of 1 mm or less, the inner diameter of the injection port is 0.3 to 1 0.0 m
It is preferable that 16 or more m nozzles are arranged on the outer periphery of the boundary between the mold and the lens, and high-pressure water is simultaneously jetted from 16 or more directions to uniformly release the lens from the mold over the entire circumference. By doing so, as described above, the bending stress applied to the lens and the mold at the time of release can be reduced, so that the crack of the lens and the mold can be remarkably reduced and the yield can be improved even for a lens having an extremely thin thickness. To do.

The thickness of the plastic lens varies depending on the type and the frequency, and in order to make the jet flow collide with the boundary between the lens and the mold, it is necessary to adjust the positions of the lens assembly and the injection nozzle for each type and frequency. There is. As the method, the position of the injection nozzle is fixed so that the jet flow collides with the flat table surface on which the lens-type assembly is placed,
The table or the injection nozzle is moved in the thickness direction of the lens by the distance (boundary height δ in FIG. 1) from the bottom surface of the lower mold to the boundary portion between the upper mold and the lens, which is measured in advance for each product type and frequency. When the table and nozzle positions are set as described above, there is no variation in the wall thickness of the lens and the lower mold, and
If the mold has a constant thickness, the jet flow surely collides with the boundary portion, and the lens is released from the mold. However, in reality, the thickness of the gasket that sets the gap between the molds, the amount of resin injected,
Since the polymerization temperature, the composition of the material and the like vary, the thickness of the lens after the polymerization varies. In addition, since the mold itself is re-polished and used again when the surface is scratched, the thickness of the mold varies. For this reason, the boundary height δ is 0.
There is a variation of about 5 to 1.5 mm. On the other hand, when releasing a lens with a particularly thin wall thickness, in order to release the tapered lens without applying excessive force,
It is preferable to inject high-pressure water simultaneously from more than one nozzle. Here, if the inner diameter of the nozzle injection port is made larger than the variation of the boundary height δ, the jet will always collide with the boundary portion, but in reality, if the inner diameter of the nozzle injection port is large, a pump with such a large capacity However, the inner diameter of the injection port of the nozzle cannot be increased so much. When the position of the lens assembly is set by the above-mentioned method, if the inner diameter of the injection port of the nozzle is small, the jet flow does not collide with the boundary against the dispersion of the boundary height δ, and the lens release success rate decreases. Will end up. Also, if the height δ of the boundary of each lens-type assembly is measured and the position of the table or nozzle is adjusted, the jet flow will surely collide with the boundary and the lens will be released from the mold as described above. To be done.
However, it is difficult to accurately and automatically detect the boundary between the lens and the mold, and if each lens-type assembly is individually measured and the position of the table or nozzle is adjusted, the takt time becomes longer and productivity becomes worse. . Therefore, in order to reliably release the lens having variations even if the nozzle diameter is small, it is preferable to set the positions of the nozzle and the lens mold assembly and release the lens by the following method.

That is, the position of the lens-type assembly or the nozzle is adjusted according to the average value of the boundary height measured in advance for each product type, and the nozzle or the lens-type assembly is adjusted to 0. High-pressure water is jetted and collided for 0.5 to 5 seconds, preferably 1 to 3 seconds while vibrating at a frequency of 5 to 20 Hz and an amplitude of 0.3 to 2 mm. By doing so, the jet flow always collides with the boundary portion, so that the mold release success rate is improved, and stable mold release with a short tact time is possible. If the jetting time is less than 0.5 seconds, the releasing effect is insufficient, and if the jetting time exceeds 5 seconds, cracks easily occur in the lens, which is not preferable. Even when vibrating the injection nozzle or the lens-type assembly, it is more preferable to use the above-mentioned technologies such as the water pressure of the injection water, the preheating temperature of the lens-type assembly, the nozzle hole diameter, the injection angle, and the number of arrangements in combination. Of course.

When the upper mold is released by the above method, in the case of a plus lens (convex lens), the lower mold is released at the same time. However, with the minus lens (concave lens), the lower mold and the lens are firmly bonded even after the upper mold is released. The upper mold has a boundary surface with the lens on the same plane, but the lower mold is flat like an astigmatic lens, and there is a case where the boundary surface with the lens is not on the same plane.
Therefore, it is difficult for a nozzle that ejects a rod-shaped straight flow to accurately collide the jet with the boundary between the lens and the mold. Therefore, for such a lens, a nozzle having a shape in which the jet is spread in a fan shape on a plane and jetted is used so that the jet surely collides with the boundary portion.
It is preferable to surely release the lens from the lower mold by jetting a jet of water of 50 kg / cm ² toward the boundary between the lower mold and the nozzle. When one mold is released, the other mold can be released with a jet of water pressure lower than the water pressure required to initially release one mold. Also, in the case of a lower mold where the boundary surface is flat and not on the same plane, while vibrating in the thickness direction with an amplitude larger than that flat surface, a straight flow is injected from the nozzle to ensure a jet flow at the boundary between the lens and the mold. Alternatively, a method of colliding and releasing the mold may be used.

As the material of the mold, for example, a non-metal inorganic material such as glass or ceramics can be used. Further, as the thermosetting resin which is a lens material, diethylene glycol bisallyl carbonate, acrylic acid ester, diallyl ester, triallyl isocyanate and the like which are generally used for plastic lenses can be used.

[0018]

According to the method of releasing a plastic lens of the present invention, high-pressure water is jetted from a nozzle to a boundary between the plastic lens and the mold, with respect to a lens-shaped assembly composed of the mold and the plastic lens. Let Due to the collision energy of the high-pressure water, the lens-type assembly causes peeling at the boundary surface between the plastic lens and the mold, and this peeling is sequentially expanded by the wedge action by the high-pressure water that is jetted sequentially, so the lens is removed from the mold. Easily released.

At this time, the position of the lens mold assembly or the nozzle is adjusted according to the average value of the boundary heights measured in advance for each lens type, and the nozzle or the lens mold assembly is adjusted at that position in the lens thickness direction. When high-pressure water is jetted while vibrating at a predetermined amplitude and frequency, the jet flow always collides with the boundary portion, so the release success rate is improved and stable release with a short tact time is possible.

[0020]

EXAMPLES AND COMPARATIVE EXAMPLES The mold releasing method of the plastic lens according to the present invention described above can be carried out, for example, by a mold releasing apparatus described below.

FIG. 1 is a schematic front view of an embodiment of a mold releasing apparatus for carrying out the mold releasing method of the present invention. 2 is shown in FIG.
FIG.

In the figure, reference numeral 7 indicates a base plate, and the base plate 7 is provided with the height of a table 15 on which the lens is mounted for each kind of lens so that the jet flow collides with the boundary surface between the lens and the mold. An elevating stage 8 for adjustment is attached. Further, the base plate 7 has a guide member 9 for moving the plate 10 up and down.
a is fixed vertically.

The plate 10 can be moved up and down while maintaining parallelism in the vertical direction in the figure by a guide member 9b, and a vibration generator 11 is attached to the upper part thereof. In the vibration generator 11, the eccentric cam 13 is attached to the tip of the rotary shaft of the motor 12 fixed on the plate 10, and the cam follower 14 is attached to the lower surface of the plate 16, so that the eccentric cam 13 rotates. The plate 16 can vibrate up and down. Further, on the plate 16, a table 15 for mounting the lens mold assembly 6 including the plastic lens L and the molds 1 and 2 shown in FIG.
Is fixed. Therefore, the lens-type assembly 6 and the table 15 can be integrally moved up and down by the rotation of the eccentric cam 13.

The holding means for holding the lens-type assembly 6 has the following structure. That is, the plate 16
Above the rack and pinion type air chuck 17, the distance between the left and right chuck claws 17 'can be expanded and reduced in synchronization.
Is attached to the chuck claws 17 ′, and two grip jigs 18 for positioning the lens assembly and pressing and fixing the outer peripheral portion are fixed to the left and right chuck claws, for a total of four. . As shown in FIG. 2, the table 15 is provided with an elongated hole 18a so that the holding jig 18 can be moved left and right. A support 19 is fixed to the plate 16, and a cylinder 20 is fixed above the support 19. A pad 21 is attached to the cylinder 20,
It can be moved up and down by the cylinder 20. The pad 21 is for pressing and fixing the lens type assembly 6 on the table by the pressing force of the cylinder 20, and for preventing the lens or the mold from being scattered by the force of the jet flow at the time of releasing the mold. As described above, when the lens mold assembly 6 is pressed and gripped from above, it is possible to prevent the lens and the mold from scattering at the time of mold release with a small gripping force as compared with the method of gripping only the outer peripheral surface of the lens. It is possible to reduce cracking of the mold without applying bending stress.

The jet device for jetting a jet of high-pressure water onto the lens-type assembly 6 has the following structure. That is, the high-pressure water jet device 40 includes the lens L and the molds 1 and 2.
For injecting high-pressure water to the boundary surface of the high pressure water by increasing the pressure of the raw water introduced from the pipe 32 with a high pressure pump 29 such as a plunger pump or a turbine pump. The high-pressure hoses 25a and 25b branched from the nozzles are jetted from a plurality of nozzles 23a and 23b attached to the tips thereof. As the high-pressure pump, it is preferable to use a plunger pump that is efficient and can obtain high water pressure. In addition, 30 is a pressure regulating valve for adjusting the discharge water pressure, and 28 is a water pressure gauge for confirming the adjusted water pressure.

The nozzles 23a and 23b are selected in advance so that a straight flow having a strong collision force can be obtained, and the injection angles θ are equally spaced around the outer periphery of the lens-shaped assembly 6 with respect to the tangent line L1 shown in FIG. , A plurality of them are arranged so as to form the above angle. Then, it is preferable that the ejection direction is the central portion of the lens-type assembly and is arranged so as to face the boundary surface. Further, as shown in FIG. 3, the distance d from the outer peripheral surface of the lens-type assembly to the tip of the nozzle is a portion called a columnar flow in which the jet flow ejected from the nozzle is not disturbed, and the collision energy from the nozzle 23a is not impaired. Therefore, it is preferable to set it in the range of 5 to 100 mm.

The nozzles 23a and 23b are selected such that a jet flow that spreads in a fan shape is obtained, and a plurality of nozzles are arranged on the outer periphery of the lens-type assembly 6 so that the jet flows spread in the thickness direction of the lens. With this nozzle, even in a lens such as an astigmatism lens in which the lower mold is flat and the boundary with the lens is not on the same plane, the jet flow collides with the boundary between the lens and the mold, so that the mold can be reliably released. it can.

Next, the releasing operation of the lens performed by this apparatus will be described.

First, in consideration of the state where the jet flow collides with the upper surface of the table, the lens L and the mold 1 are placed from the bottom surface of the table when the lens-type assembly, which has been measured for each lens type in advance, is placed on the flat table. Based on the average value of the height δ (boundary height) to the boundary surface between and, the table 15 is lowered by the distance of the height δ. Then, the lens-shaped assembly 6 which has been kept warm in the oven in advance is placed on the table 15
Place on top. By closing the chuck 17 ', the holding jig 18 holds the outer peripheral surface of the lens-type assembly. The lens-type assembly 6 is positioned and fixed at the center of the plurality of nozzles arranged on the outer circumference. Next, the cylinder 20 is driven to lower the pad 22 to fix the lens-type assembly 6 on the table 15 from above.

When the motor 12 is rotated in this state, the eccentric cam 13 is rotated to move the cam follower 14 up and down, and the gripping mechanism attached to the plate 16 and the lens type assembly are integrated into a lens thickness direction. Vibrate to.

When the valve 27a is opened for 0.5 to 5 seconds while the lens assembly 6 is vertically vibrated, the jet flow ejected from the nozzle 23a surely collides with the boundary surface between the lens and the mold, and the mold 1 is The mold is released from the lens L. When the lens is a convex lens, the mold 2 also releases the mold 2 from the lens L at the same time. However, some types of concave lenses can be obtained by simply releasing the mold 1 from the lens.
Does not release. In the case of this kind of product, the valve 27b
Also, the fan-shaped jet flow ejected from the nozzle 23b is collided with the lens mold assembly to release the lens L and the mold 2.

Example 1 In order to investigate the influence of the water pressure of the water jet from the nozzle 23 on the release success rate and the cracking rate of the lens or mold,
A mold release test is performed on 300 lens-type assemblies in which the lens L is very firmly attached to the molds 1 and ² by changing the discharge water pressure of the high-pressure pump 29 within a range of 50 to 350 kg / cm ^2. It was

The breakdown of 300 lens-type assemblies is that the lens L has a power of +1.0 degrees (convex lens), +
100 for each mold assembly in which three types of lenses A, B, and C of 2.0 degrees (convex lens) and -2.0 degrees (concave lens) are molded
It is an individual. As the releasing conditions other than the water pressure, pure water having an electric conductivity of 50 μS / cm was preheated to 20 ° C. by a preheating device (not shown) as raw water and sprayed for about 0.5 to 2 seconds. In addition, the lens type assembly 6 is preliminarily placed in the oven 1
Preheated to 00 ° C. As the nozzle 23a, one nozzle having an inner diameter of 1.0 mm was fixed so that the injection angle θ was 0 ° and the distance d between the lens-type assembly 6 and the tip of the nozzle 10a was 10 mm.

A mold release test was conducted under these conditions, and it is shown in Table 1 below that shows whether or not the lens could be released from the lens mold assembly without any problem.

[0035]

[Table 1] From Table 1, according to the method of releasing the plastic lens of the present invention, the injection pressure of the high pressure water is approximately 80 to 300 kg / cm.
It turns out that a good result is obtained with a value of ² .

Next, out of the above-mentioned three types of lens mold assemblies 300, only 100 mold assemblies in which the lens B is molded have a water pressure of 180 kg / cm ² , and other conditions are the same as above. A mold test was conducted, and the number of lenses that could be released without any problems with respect to the total number of mold assemblies was specifically defined as the release success rate, and the number of cracks in the lens or mold with respect to the total number of mold assemblies was specifically defined as the cracking incidence. When examined, as shown in Table 2, they were 100%, 1%, and 4%, respectively.

Comparative Example On the other hand, the conventional method of releasing a mold by irradiating far infrared rays (conventional method) is omitted because there is no concrete data, but a releasing method using a vise and a blade. Using a (conventional method) and a releasing method (conventional method) in which heat shock is applied, a releasing test was performed on a lens mold assembly in which the same lens A as in Example 1 was molded.

According to the conventional mold releasing method, a lens mold assembly preheated to 100 ° C. in an oven is fixed to a vise, and the tip of the cutting tool is inserted into the boundary surface between the lens L and the molds 1 and 2 and separated. The mold releasing method of the conventional method was a method of immersing the lens mold assembly preheated to 100 ° C. in warm water of 80 ° C. for 10 seconds and then immersing it in warm water of 45 ° C.

The following Table 2 summarizes the above Example 1 and Comparative Example 1.

[0040]

[Table 2] From Table 2, the mold releasing method of the present invention can reliably mold-release even high-level convex lenses in which the lens and the mold are firmly adhered, which cannot be completely released by the conventional method. It has been found that, compared with the conventional method, the incidence of cracks in the lens and the mold can be significantly reduced.

Embodiment 2 Next, in order to search for a preferable jet angle θ of the nozzle 10a, the jet angle θ of high-pressure water is set to -30 ° to 10 ° with respect to 100 lens-shaped assemblies in which the lens B is molded. 5 for each
A mold release test was conducted by changing the temperature gradually to 0 °.

The releasing condition is that the water pressure is 180 kg / c.
m ² , the inner diameter of the injection port of the nozzle is 1.0 mm, the distance d between the lens type assembly and the tip of the nozzle is 10 mm, and the water temperature of the raw water is 2
The preheating temperature of the lens assembly was 0 ° C., the number of nozzles was 1, and the ejection time was about 0.5 to 2 seconds.

The results are shown in FIGS. 4 and 5, and as shown in FIG. 4, the release success rate of the lens L is about 80 to 100 when the injection angle θ is −20 to 30 °. It was found to show a high value of%. Also, as shown in FIG.
It was found that the crack occurrence rate of the mold was significantly increased when the injection angle θ of the high pressure water was 30 ° or more. At injection angles other than the above, the success rate of mold release can be improved by increasing the water pressure or the inner diameter of the nozzle outlet to increase the injection energy, but a pump with a larger capacity is required. Therefore, it is not economical. Therefore, in order to increase the mold release success rate and reduce the mold crack occurrence rate, it is preferable that the injection angle be in the above range.

Example 3 Next, in order to search for a preferable preheating temperature of the lens-type assembly 6, the preheating temperature was set to 20 to 100 ° C. at every 20 ° C. for 100 lens-type assemblies same as those in Example 2. The mold release test was performed by changing the temperature in stages.

The mold release conditions are water pressure of 180 kg / cm ²
The releasing conditions other than the preheating temperature are the same as in Example 1.

FIG. 6 shows the result, and the preheating temperature of the lens-type assembly is 60 ° C. or higher, more preferably 80 ° C.
It was found that the release success rate was significantly improved by the above. Example 4 Next, in order to search for a preferable nozzle inner diameter, the inner diameter of the injection port of the nozzle is changed stepwise within the range of 0.1 to 2.0 mm for 100 lens-type assemblies which are the same as those of the second embodiment. Let
A mold release test was performed for each inner diameter.

The mold releasing conditions are 180 kg / cm ² of water pressure at each nozzle inner diameter, and the mold releasing conditions other than the nozzle inner diameter are the same as in the first embodiment.

This result is shown in FIG. 7, and it has been found that when the nozzle inner diameter is 0.3 to 1.5 mm, the release success rate is improved. That is, whether or not the lens can be released is determined by the correlation between the water pressure of the high-pressure jet and the inner diameter of the nozzle outlet. Therefore, at the same water pressure, the larger the inner diameter of the nozzle outlet, the higher the release success rate. However, as shown in FIG. 7, when the nozzle inner diameter is 0.3 mm or less, the release success rate is remarkably reduced.
On the contrary, it can be seen that the release success rate does not improve so much even if it is 1.5 mm or more.

Embodiment 5 Next, in order to search for a preferable water temperature of the high pressure water to be injected,
A mold release test was conducted for each water temperature by changing the water temperature stepwise in the range of 20 ° C. to 80 ° C. at every 20 ° C. for the same 100 lens-type assemblies as in Example 2.

The releasing condition is that the water pressure is 180 kg / cm ²
The releasing conditions other than the water temperature are the same as in Example 1.

This result is shown in FIG. 8. Since the lens-type assembly has been preheated to 100 ° C.,
If the water temperature of the jet water is low, the probability that the mold will crack due to the rapid lens and mold heat contraction due to heat shock increases, and if the water temperature is 60 ° C or higher, it is very effective in reducing the cracking of the mold. I understand.

Example 6 An aspherical lens whose curvature is not constant is very fragile because of its thin wall thickness and low strength. In order to find a preferable nozzle arrangement number for such an aspherical lens that is particularly fragile, an aspherical lens having a lens power of +5.0 degrees, a diameter of 73 mm, and a peripheral portion thickness of 0.8 mm was molded. The following mold release test was performed on the lens mold assembly 6.

The mold release conditions are water pressure of 120 kg / cm ² , nozzle nozzle inner diameter of 0.3 mm, and high-pressure water incident angle of 0 mm.
°, the distance between the lens type assembly and the tip of the nozzle is 15 mm, the water temperature is 20 ° C, the preheating temperature of the lens type assembly is 100 ° C,
A plurality of nozzles were arranged at equal intervals on the outer peripheral portion of the lens-type assembly, and high-pressure water was simultaneously made to collide with the boundary portion from a plurality of directions for about 1.5 to 3.5 seconds to release the lens.

The results are shown in Table 3 below, and when the number of nozzles is 16 or more, it is very effective in reducing the cracks in the lens and the mold of the aspherical lens which are easily broken. I understand.

[0055]

[Table 3] Example 7 In order to confirm the effect of the present invention on the lens mold assembly 6 in which the lens and the mold have different thicknesses, the lens power is −2.0 degrees, the diameter is 80 mm, and the outer peripheral thickness is 5.0.
The following mold release test was performed on 100 lens mold assemblies in which a spherical lens having a size of mm and a boundary height δ having a maximum variation of 1.2 mm was molded.

The mold release conditions are water pressure of 100 kg / cm ² , nozzle nozzle inner diameter of 0.4 mm, and high-pressure water incident angle of 0 mm.
°, the distance between the lens type assembly and the tip of the nozzle is 15 mm, the water temperature is 20 ° C, the preheating temperature of the lens type assembly is 100 ° C,
Twenty-four nozzles were arranged at equal intervals on the outer peripheral portion of the lens-type assembly, and the table height was adjusted based on the average value of the boundary height measured in advance. Then, a mold release test is performed depending on whether the high pressure water is sprayed or not while vibrating the lens assembly, and when vibrating, the table on which the lens assembly is mounted has a vibration frequency of 2 Hz and an amplitude. High-pressure water was jetted for 2 to 4 seconds while vibrating under a vibration condition of 2 mm.

The results are shown in Table 4 below. It has been found that the method of ejecting high-pressure water while vibrating the lens-type assembly improves the release success rate as compared with the case where the lens-type assembly is not vibrated.

[0058]

[Table 4]

[0059]

As described above, in the mold releasing method for the plastic lens according to the present invention, the thermosetting resin is injected into the gap of the mold having a constant gap and solidified to mold the plastic lens. Then, by injecting high-pressure water having a water pressure of 80 to 300 kg / cm ² onto the boundary between the mold and the lens of the lens mold assembly in which the mold and the lens are integrated, Since the method of releasing the lens is adopted, even if the lens-type assembly in which the lens is firmly adhered to the mold,
Also, even if the lens type assembly is thin and very easy to break, it is an excellent effect that the worker can reliably and quickly release the mold without requiring any skill and without damaging the lens and the mold. Can be played.

In the plastic lens releasing apparatus according to the present invention, there is provided a table on which a lens type assembly in which a mold and a lens are integrated is placed, and a holding means for holding the lens type assembly on the table. And a high-pressure water injection means for injecting high-pressure water onto the lens-type assembly, in a mold releasing device for a plastic lens, the pressure of the high-pressure water is 80 to
Since the water pressure adjusting means for adjusting the water pressure to 300 kg / cm ² is provided, it is possible to obtain the mold releasing device which can exhibit the above-mentioned excellent effects. In the case where a vibration means for vibrating the high-pressure water jet nozzle or the lens type assembly in the thickness direction of the lens at a frequency of 0.5 to 20 Hz and an amplitude of 0.3 to 2 mm is added to the above apparatus, Even with a lens-type assembly in which the thickness of the lens and the mold vary, the mold can be easily released without damaging the lens and the mold.

[Brief description of drawings]

FIG. 1 is a schematic front view showing an embodiment of a mold releasing apparatus for carrying out a plastic lens mold releasing method according to the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

3 is a vertical cross-sectional view showing the positional relationship between the lens-type assembly and the nozzle shown in FIG.

FIG. 4 is a diagram showing a correlation between an ejection angle of high-pressure water and a release success rate of a lens.

FIG. 5 is a diagram showing a correlation between an injection angle of high-pressure water and a crack occurrence rate of a mold.

FIG. 6 is a diagram showing a correlation between a preheating temperature of a lens molded product and a lens release success rate.

FIG. 7 is a diagram showing a correlation between a nozzle inner diameter and a lens release success rate.

FIG. 8 is a diagram showing a correlation between a water temperature of jet water and a mold crack occurrence rate.

FIG. 9 is a vertical cross-sectional view of a lens mold assembly which is a mold release target of the method and apparatus of the present invention.

[Explanation of symbols]

 1, 2 ... Mold 3 ... Gasket 4 ... Injection port 5 ... Clip 6 ... Lens type assembly 7 ... Base plate 8 ... Elevating stage 9a, 9b ... Guide member 10 ... Plate 11 ... Vibration Generator 12 …… Motor 13 …… Eccentric cam 14 …… Cam follower 15 …… Table 16 …… Plate 17 …… Air chuck 17 ′ …… Chuck claw 18 …… Grip jig 19 …… Supporting base 20 …… Cylinder 21 ...... Pad 22 …… Grip mechanism 23a, 23b …… Nozzle 24 …… Coupling 25 …… High pressure hose 26 …… Branch pipe 27a, 27b …… Valve 28 …… Pressure gauge 29 …… Pump 30 …… Pressure control valve 31 …… … Tank 40 …… High-pressure water generator L …… Lens L1, L2 …… Tangential line θ …… Spray angle δ …… Boundary height

Claims (9)

[Claims] 1. A mold having a fixed gap, in which a thermosetting resin is injected into the gap and solidified to mold a plastic lens, and then the mold of a lens type assembly in which the mold and the lens are integrated. A method for releasing a plastic lens, characterized in that the lens is released from the mold by jetting high-pressure water having a water pressure of 80 to 300 kg / cm ² to the boundary between the lens and the lens. 2. When the high-pressure water is jetted to the boundary between the mold and the lens, the lens mold assembly is preheated to 60 to 120 ° C., and then the high-pressure water is injected into the lens mold assembly. The inner diameter is 0.3 to 1. With respect to the tangent line drawn to the boundary surface between the lens and the mold in the outer peripheral portion.
The method for releasing a plastic lens according to claim 1, wherein the injection is performed at an injection angle of -20 to 30 ° from a 5 mm injection nozzle. 3. The mold releasing method for a plastic lens according to claim 2, wherein the temperature of the high-pressure water is 60 to 90 ° C. 4. A plurality of the high-pressure water jet nozzles are arranged on an outer peripheral portion of a boundary portion between the mold and the lens, and jet the high-pressure water simultaneously from a plurality of directions. The method for releasing the plastic lens of 2, or 3. 5. The high-pressure water jet nozzle or lens-type assembly at a frequency of 0.5 to 20 Hz in the lens thickness direction,
The plastic lens according to claim 1, 2, 3, or 4, wherein high-pressure water is jetted to the boundary between the mold and the lens for 0.5 to 5 seconds while vibrating at an amplitude of 0.3 to 2 mm. Mold release method. 6. A table on which a lens type assembly in which a mold and a lens are integrated is placed, a holding means for holding the lens type assembly on the table, and high pressure water is applied to the lens type assembly. A plastic lens release device having high-pressure water jetting means for jetting water, wherein a water pressure adjusting means for adjusting the pressure of the high-pressure water to a water pressure of 80 to 300 kg / cm ² is provided. Mold release device. 7. The plastic article according to claim 6, further comprising preheating means for preheating the lens mold assembly to a temperature of 60 to 120 ° C. when the high pressure water is jetted to the lens mold assembly. Lens release device. 8. A vibrating means for vibrating the jet nozzle or the gripping means of the lens-type assembly at a frequency of 0.5 to 20 Hz and an amplitude of 0.3 to 2 mm in the thickness direction of the lens is provided. The mold releasing device for a plastic lens according to claim 7, wherein. 9. A gripping means for the lens-type assembly is a gripping jig for pressing the lens-type assembly from the outer diameter direction, and a pressing means which is arranged so as to face the table and moves back and forth in the thickness direction of the lens. 9. The mold releasing device for a plastic lens according to claim 6, 7 or 8, further comprising a pad having