JPH02235729A - Manufacture of plastic optical component and device thereof - Google Patents

Abstract

PURPOSE:To reduce the time required for lens-forming while the accuracy of the shape of the lens is kept at a desired extent by a method in which after the sheet like plastic material to be press-formed has been heated in a thermal deformation temperature range, it is transferred and placed between dies of a top force and a bottom force of first press process, and then a prescribed optical shape is obtained by press-forming, in order, in each of a plurality of press processes. CONSTITUTION:Sheet material 7 is advanced through a prescribed distance by transferring clamps 8, 8', and the part heated in thermal deformation temperature-range and softened, is moved into the true center of the dies 1, 1' of to and bottom forces of first process, and the movement of the sheet material is stopped there. Cylinders 4, 4' are driven, and the dies 1, 1' of the top and bottom forces begin shaping so as to nip the sheet 7, and pressurize the sheet until a limiter is operated. After the passage of a prescribed time, the dies 1, 1' of the top and bottom forces are opened, and the transferring clamps 8, 8' are operated, whereby the lens L1 pressurized and shaped in the first process is transferred into between the dies 2, 2' of the top and bottom forces of a second process. Then, a desired final lens L3 is obtained through entirely the same process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for manufacturing plastic optical components, and particularly to a method for manufacturing plastic optical components suitable for shortening manufacturing time and reducing costs. and its equipment.

[Prior Art] As the field of use of optical systems expands, including the spread of video cameras, there is a demand for optical components, especially inexpensive and lightweight lenses that can replace glass lens beads.Plastic lenses have been meeting these needs. Ta.

In recent years, this need has increased more and more, and the demand for lenses, which are optical elements, is rapidly expanding.

Conventionally proposed methods for manufacturing plastic lenses include, for example, as described in Japanese Patent Application Laid-open No. 55-27300, in which high-temperature molten plastic is molded at a similarly high temperature (more specifically, it is molded). The plastic is filled into a mold held in the glass transition temperature region of the material, so that the filled plastic is uniform at the glass transition temperature (T9), and then cooled to obtain a lens. In this method, by making the temperature inside the lens uniform at the T9 temperature, local shrinkage (sink marks) can be prevented and a highly accurate lens can be obtained. However, it is necessary to take a long time to make the temperature inside the lens uniform.

In addition, Japanese Patent Application Laid-Open No. 58-12738 discloses that the mold is heated immediately after the center (thick walled part) of the plastic filled in the mold reaches the solidification temperature, and only the surface layer of the lens is melted or softened. However, a method has been proposed in which the mold is remolded by applying pressure. In this method, only the face of the lens is reshaped, so the volumetric shrinkage is small, and the molten layer uniformly shrinks only on the surface layer, regardless of the thickness deviation ratio of the lens, so a highly accurate lens can be obtained. However, it is necessary to reheat the mold and take a long time to cool it down.

In this specification, the term "shaping" is used as described above, but "shaping" refers to pressure forming to give a special shape, and is used in the plastic processing industry such as presses. This is the term used.

Returning to the explanation of the prior art, JP-A-59-124819 discloses that a base material (blank) that approximates the final desired shape is prepared, and the surface layer of the blank is heated and melted to have an optical shape. A method has been proposed in which a mold is pressed against the molten surface to obtain a plastic optical component.

According to this method, a highly accurate plastic lens can be obtained as in the above-mentioned Japanese Patent Laid-Open No. 58-12738. However, the time for producing the blank as well as the time for heating and fluidizing the surface layer of the blank must be considered.

[Problems to be Solved by the Invention] In the above-mentioned prior art, with regard to the shape precision of optical components, particularly lenses, sufficient studies have been made on means for ensuring the precision. However, no consideration was given to the long manufacturing time, such as the molding cycle and molding tact.

The present invention has been made in order to solve the above-mentioned problems in the prior art, and it shortens the molding time of optical components while forming lenses with desired precision, thereby reducing the unit cost of optical components. Its purpose is to provide a manufacturing method and apparatus.

[Means for Solving the Problems] In order to achieve the above object, the structure of the method for manufacturing a plastic optical component according to the present invention is such that at least two sets of upper and lower dies facing each other are provided with an interval between them. A plurality of pressing processes for each die are performed, and the cavity shape of the die used in these plurality of press processes is sequentially changed for each die so that the optical component to be press-molded obtains a predetermined shape in the final pressing process. At the same time, the sheet-like plastic material to be press-formed is heated to the heat deformation temperature range, and then transferred between the upper and lower dies in the first press step, and then sequentially pressed in each of the following press steps. It is molded to obtain a predetermined optical shape.

Furthermore, in order to achieve the above object, the apparatus for manufacturing a plastic optical component according to the present invention includes a means for transporting a sheet-like plastic material to be press-molded, and a means for heating the sheet-like plastic material to a heat distortion temperature range. It is equipped with a heating means, and a press molding device in which at least two or more sets of presses each consisting of an upper die and a lower die facing each other are provided at intervals, and the plurality of presses in this press forming device are arranged so that the cavity shape of each die is adjusted. are sequentially changed so that the optical component to be press-molded has a predetermined shape in the final press.

It should be noted that the above object is achieved by reducing the high-speed time in a mold for ensuring the shape accuracy of an optical component, such as a lens. In other words, it eliminates the process of filling a mold held at high temperature with molten plastic for a certain period of time and reheating the mold as in the conventional technology.The basic method is to heat the mold in advance. A sheet-like plastic material held in a deformation temperature range is sequentially pressurized and shaped using a plurality of dies with slightly different cavity shapes (optical shapes).

As a result, plastic lenses are molded into a predetermined optical shape from sheet material through several steps, but because the holding time in the mold (die) is short, the manufacturing tact is extremely small, achieving the above objective. It is something.

[Effect] The working of the above technical means is as follows.

The sheet-shaped plastic is held in a heat deformation temperature range where it can be easily molded, and is processed into an optical component having a predetermined optical shape, such as a lens, while being cooled through a plurality of dies. The cavity shapes of the plurality of dies are slightly changed, and the shape of the final die is the closest to the desired lens shape. Therefore, there is no need to spend time shaping each step. Also, the mold temperature should be in the heat distortion temperature range or within the heat distortion temperature range. The temperature range.
It is set to a constant value slightly lower than the range. Therefore, there is no need for time for heating or cooling the mold during molding.

[Example] Hereinafter, each example of the present invention will be described with reference to FIGS. 1 to 13.

Fig. 1 is a schematic side view of a plastic lens manufacturing apparatus according to an embodiment of the present invention, Fig. 2 is a cross-sectional view of a model explaining the die shown in Fig. 1, and Fig. 3 shows its pressurizing method. It is a model sectional view for explanation.

In FIG. 1, 7 is a sheet-shaped plastic material (hereinafter simply referred to as sheet material) 8, 8' to be press-molded.
It is a transfer clamp related to a means for transferring the sheet material 7,
The transfer clamps 8, 8' operate synchronously at regular intervals according to commands from a transfer controller (not shown).

Reference numeral 9 denotes a heating means for heating the sheet material 7 to a heat deformation temperature range, such as an infrared heater (hereinafter simply referred to as a heater).

1, 2.3 is a cavity surface 1a having an optical shape,
The shape of the cavity (the shape of the cavity surface) of these dies is the same as that of the upper die 1.
, 2.3 are changed little by little in order to approach the desired shape.

The upper mold die l, 2.3 is fixed to the rod 4a, 5a, 6a and connected to the cylinder 4, 5.6. By driving the cylinders 4, 5.6, the upper die 1, 2.3 performs a so-called press operation.

Similarly, 1', 2', and 3' are lower mold dies in which cavity surfaces 1'a, 2'a, and 3'a having optical shapes are formed, and the cavity shapes of these dies are also the same as those of the lower mold die 1'. , 2', and 3' are slightly changed in order to approach the desired shape.

The lower die l', 2'3' is the rod 4' a,
Cylinders 4', 5' .
It is connected to 6'. And cylinders 4', 5'6
By driving ', the lower dies 1', 2', and 3' perform pressing operations in the same way as the upper dies. The upper and lower cylinders are synchronized and press simultaneously in the vertical direction in the figure at fixed time intervals according to commands from the main controller (not shown), and the cylinder operation timing is controlled by the transfer clamp 8, Sequence control is performed to operate after the drive of 8' is completed.

The pressing operation in the press having the upper and lower dies 1 and 1' is the first step, and the pressing operation in the press having the upper and lower dies 2 and 2 is the second step, and the upper and lower dies 3.3
The press operation in the press having 1' is the third step, and in the embodiment shown in FIG. configuring the device.

In addition, 10.10' shows the frame of this press molding apparatus.

In the apparatus of this embodiment configured as described above. The operating procedure will be explained.

When the sheet material 7 having a width and thickness slightly larger than the outer diameter and maximum wall thickness of the desired lens is attached to the transfer clamp 8 and the transfer clamp 8 is operated, the sheet material 7 is transferred between the heaters 9 and 9'. It then passes through the upper and lower die entrances and reaches the other transfer clamp 8'. Therefore, sheet material 7
After attaching the transfer clamp 8' to the transfer clamp 8', the power to the main controller is turned on.

The heaters 9, 9' and the cylinder are activated, and the sheet material 7 is heated by the heaters 9, 9' to increase the required area range of the sheet material 7 to the heat distortion temperature range of that material. The upper mold dies 1 to 3 and the lower mold dies 1' to 3' are in an open state and on standby.

When a temperature sensor (not shown) set in the heater 9 indicates that the sheet material 7 has reached the heat deformation temperature range, for example by an infrared detector, the main control device is activated and all The devices start operating synchronously.

First, the sheet material 7 is advanced a certain distance by the transfer clamp 8, 8', and the softened portion is heated to the heat deformation temperature range by the heaters 9, 9' and is transferred to the upper and lower dies 1, 1 in the first step.
′, and the movement of the sheet material stops here.

Cylinder 4. , 4' drive the upper and lower dies 1, 1.
' is sheet material 7? Shaping is started while holding the sample, and pressure is applied until a limiter (not shown) is activated. At this time, the temperature of the dice is controlled by temperature control means 1, which will be described later in FIG.
6, the temperature is constantly adjusted to a temperature in the heat deformation temperature range or slightly lower than the temperature. After the limiter is activated, it stops at that position and is held in place by the elastic recovery force of the press-molded lens to prevent the mold from opening. After a certain period of time has passed, the upper and lower dies 1 and 1' are opened, the transfer clamps 8 and 8' are activated, and the lens L1 that has been pressurized and shaped in the first step is transferred to the second
At the top of the process, it is transferred between the lower die 2 and 2'. The lens L and the sheet material 7 are not separated yet and move together. At the same time, the parts softened by heaters 9 and 9' are
It has moved to the die position for the first step.

The operation in the second step is exactly the same as in the first step, and the lens L is reshaped. Similarly, the lens L2 shaped in the second step is shaped again in the third step to obtain the desired final lens L3.

The above is an embodiment of the method for manufacturing a plastic lens according to the present invention.

The first step in the method of manufacturing a plastic lens according to this embodiment
The feature of this is that the sheet material 7 is heated in advance to the heat distortion temperature range. Not only is the FX type easy to use, but the temperature range is selected so that it solidifies immediately when the temperature drops below that range.

This can overcome the drawback of plastics being difficult to cool down, and has the effect of reducing the cooling time within the mold (die).

The heat distortion temperature referred to here is defined as follows.

American Society for Testing Materials
r Testing Materials Abbreviation ASTM
Temperature according to the measurement method specified in
2 inch, 178-172 inch thick test specimens are supported at 4 inch intervals with 264 (or 6
6) Temperature at which pounds of fiber stress is applied and the center deflection reaches 0.01 inch.

Or, the Vicat softening point specified by the above ASTM, that is, the temperature when the penetration depth reaches 1 mm when a load of 1 kg is applied to a needle with a cross-sectional area of 1 mrrr. The specific temperature defined in this way is called the heat distortion temperature, and ±
10°C was applied as the heat distortion temperature range. The second method of manufacturing a plastic lens according to this embodiment
The feature is that there are multiple press molding forming processes (three in this example), and the almost optical shape of the cavity surface of the die group used in each of these processes is sequentially and slightly changed. It is. Next, a more detailed explanation will be given with reference to FIG.

Figure 2 shows a model of the die in Figure 1, where L1 is the lens shaped in the first step, and 3 and 3' are the upper and lower dies used in the third step. be. la,2
a and 3a indicate the cavity surface shapes of the dies used in the first, second, and third steps, respectively, and l/a,
The same applies to 21a, 3/d.

The first step has the role of shaping the sheet material 7 into a rough lens shape, and forms the cavity surfaces 1a, 1'.
A lens L having an approximate shape according to a? Press molded. In this step, the surface roughness and shape of the outer shape of the lens L2 are not so strict, and it can be considered as a pretreatment step for lens molding.

In the second step, the cavity surfaces 2a, 2'a are applied, and the lens L which has been shaped in the first step is further pressurized and shaped.

The purpose of the second step is to obtain a lens L2 having a substantially desired shape, and it is desirable that the surface roughness be finished to be substantially a chain surface.

The third step is a precision finishing step.

In this step, the material is shaped to obtain a desired shape and to satisfy optical characteristics.

The shaping process of the second and third steps will be explained with reference to FIG.

Figure 3 shows a model of the die in Figure 1.
L■pLz is the lens shaped in the first and second steps, 2,
3.2' and 3' are dies used in the second and third steps. The same symbols as in Figures 1 and 2 indicate the same parts. In the shaping process in the second and third steps, as shown in the third factor, it is desirable that pressure is applied from the region of the axial center 12 of the lens shaped in the previous step. A wedge-shaped space 11 is formed between the die and the lens, and the lens is gradually pressure-molded axially symmetrically around the outer periphery of the lens.This manufacturing method eliminates the risk of gases such as air being drawn into the boundary between the lens and the cavity surface. There is no.

Third step in the method of manufacturing a plastic lens of this embodiment
The feature is that the die is equipped with a cutter blade for separating the lens from the sheet material 7. This will be explained in detail with reference to FIGS. 4 and 5.

Figure 4 shows the second process die equipped with a cutter blade.
The enlarged sectional view, FIG. 5, is an enlarged sectional view of the die in the third step.

In Figures 4 and 5, 13 is a cutter blade protruding from the upper die, 13' is a blade receiving part provided on the lower die,
This blade receiving portion 13' guides the cutter blade 13.

In the second step, the sheet material 7 begins to be cut into a ring shape by the cutter blade 13 at the same time as the lens L2 is formed. However, this cutting operation does not separate the lens L2 from the sheet material 7. Subsequently, the process moves to the third step, and in this step, the lens L3 is cut from the sheet material 7 as a lens ball.

Note that the change in the cavity shape between the second step in FIG. 4 and the third step in FIG. will not leak.

FIG. 6 is a perspective view showing an example of a lens manufactured by the apparatus shown in FIG. 1.

In Figs. 4 and 5, it was explained that the lens beads are taken out using a cutter blade during the pressing process, but as shown in Fig. 6, the sheet material 7 and the lens L are integrally formed and cut in a separate process. It is also possible to do so. A fourth feature of the plastic lens manufacturing method of this embodiment is that a decompression means is provided to exhaust air and the like within the cavity for the purpose of improving transfer accuracy and shape accuracy. This feature will be explained in detail with reference to FIG.

FIG. 7 is a detailed sectional view showing the die structure of FIG. 1, and shows the die part of the second step of the embodiment applied to the second and third steps shown in FIG. It is.

In FIG. 7, 14 is a wedge-shaped space 1l in the cavity.
The exhaust hole 15 communicating with the exhaust hole 15 is a shutoff valve provided in the exhaust pipe 17 connected to a vacuum pump (not shown).

By clamping the upper and lower dies 2.2', a wedge-shaped space 11 is formed within the cavity as shown in FIG. If shaping is performed after opening the shutoff valve 15 as appropriate and starting pressure reduction through the exhaust hole 14, the gas in the cavity will be exhausted during the multi-stage pressing process, and shape defects due to gas entrainment will be avoided. This can be avoided, and it is possible to achieve high-precision shaping and improve shape accuracy.

Furthermore, the fifth feature of the plastic lens manufacturing method of this embodiment is that liquid temperature control means 16 for controlling the temperature of each die are provided on the upper and lower dies as shown in FIG. .

In the press molding process of this embodiment, it is desirable that the temperature of the die be maintained near the heat distortion temperature range. If the heat distortion temperature is T'C, then the die temperature in the first process is T±10℃, the die temperature in the second process is T+10~20℃, and the die temperature in the third process is T-10~20℃. Set. In the above example, it is important to always maintain the sheet material 7 in a temperature range where it is easy to shape it, and the temperature setting range is not particularly specified as long as the die temperature is set to ensure shapeability up to the third step. ．． According to the above-described plastic lens manufacturing method and apparatus of the present embodiment, the problems that have arisen with conventional injection molding methods are improved, and various advantages shown below are produced.

The first advantage is that it eliminates the weld line peculiar to concave lenses. This will be explained in comparison with the prior art shown in FIG.

FIG. 12 is a schematic diagram showing resin flow of a concave lens formed by conventional injection molding, in which (a) is a side view, (b) is a side view, and (b) is a side view. (c
) and (d) are plan views.

In conventional injection molding, the runner 19, gate 2
The molten plastic flows into the lens portion L through 3. As shown in FIG. 12 (c1), the flow of plastic at this time is caused by the thick wall around the lens L. It flows as shown by the arrow 24, and it is difficult to flow from the thin walled portion L. Therefore, the same figure (d)
As shown in FIG. 2, the merging portion of the plastic remains as a line, forming a so-called weld line 25. This weld line 25 not only reduces the product value, but also
There is a problem in that optical properties are deteriorated due to birefringence due to the weld line.

However, according to the manufacturing method of this embodiment, since a sheet material having a uniform thickness is pressed and shaped in an axially symmetrical manner, weld lines do not occur as in the prior art described above.

Next, the second advantage of the manufacturing method of this embodiment is that the non-axisymmetric nature of temperature distribution due to runners and gates and the non-axisymmetric nature of plastic flow as in the prior art are eliminated.

In conventional injection molding, the runner 1 shown in FIG. 12(b)
The volume of the lens portion 9 is often equal to or, in rare cases, larger than the volume of the lens portion L. The shape accuracy of the lens is strictly controlled by means for controlling the temperature distribution of the cavity in contact with the lens, and the lens is cooled and solidified, but due to the heat capacity of the runner 19, the temperature distribution of the cavity becomes axisymmetric.

This causes distortion in the optical shape of the lens, and is a factor in deteriorating optical performance.

Similarly, concentrated filling of the cavity from one direction by the gate is accompanied by random orientation of the resin, causing the above-mentioned shape deterioration.

According to the manufacturing method of this embodiment, since there is no need to provide a gate and a runner, non-axisymmetry due to these does not occur.

A third advantage of the plastic lens manufacturing method described with reference to FIG. 1 is that the problem of multi-lens manufacturing in the prior art is eliminated.

This will be explained in comparison with the prior art shown in FIG.

FIG. 13 is a plan view of a lens obtained by conventional four-cavity molding.

Lenses L(1), L(2), shown in FIG.
L (3) and L (4) are strictly controlled by the temperature control means of each cavity, but even though the heat source is configured with the same specifications, due to variations in the processing of the parts, the temperature of each cavity varies. Temperatures do not match.

This doesn't change anything; the lenses L (1) and L (2
), L (3) and L (4), which causes variations.

Similarly, the shape of the insert piece used for each cavity has a shape error due to processing error, and a lens molded with the insert piece having this shape error will have at least the shape error of the insert piece as a shape variation. will be affected.

Furthermore, machining errors also occur in the runner 19 and gate 23. Therefore, the amount of resin distributed to each cavity is different, which causes variations in lens shape. Such variations in the shape of lenses in multi-cavity molding are a major cause of a decrease in yield.

In the manufacturing method of this embodiment, as shown in FIG. 1, since the lenses L3 that are sequentially produced are molded through the same die, there is a difference in temperature distribution between each cavity as in the prior art shown in FIG. 13. There are no effects from differences in resin flow due to the design of the runner, gate, or cavity shape. Furthermore, the fourth advantage of the plastic lens manufacturing method explained in FIG. 1 is that it eliminates surface defects and internal distortions that tend to occur with the conventional method. In conventional injection molding, when resin is filled into the cavity from the gate, air is trapped at the gate,
Jetting flow occurs and surface defects such as wrinkles and flash are likely to occur.

In addition, we can prevent resin shortage due to resin shrinkage within the cavity.
It is replenished from the gate in a process called holding pressure, but this becomes internal strain around the gate and freezes.

This internal strain causes deterioration of the shape of the lens and deterioration of optical characteristics due to long-term release of strain or release due to environmental temperature.

Since there is no gate in the manufacturing method of this embodiment, such a problem cannot occur.

As mentioned above, the plastic lens manufacturing method of this example not only shortens the molding cycle, which is the main purpose, but also
Concomitant effects unique to this embodiment are also significant.

In summary, according to this embodiment, there is no need to fill a mold maintained at a high temperature with a low-viscosity material melted at a high temperature as in the conventional method, and it is possible to ensure shape accuracy. ,
It is not necessary to secure a holding time at a high temperature or to heat the lens again after cooling.
The lens is shaped by a pressing process, and the cooling of the lens begins at the same time as shaping, so the molding is completed in a short time. In addition, shaping through a multi-step press process not only maintains the shape accuracy of the lens with high precision, but the total shaping time due to the multi-step process is mainly the time required for the press operation.
Molding time can be significantly reduced compared to conventional methods.

The manufacturing apparatus of this embodiment can produce plastic lenses within several seconds to several tens of seconds, and is therefore suitable for producing inexpensive lens balls.

Next, another embodiment of the present invention will be described with reference to FIGS. 8 to 11.

FIG. 8 is a schematic side view of a press molding apparatus of a plastic lens manufacturing apparatus according to another embodiment of the present invention. Components in the figure with the same reference numerals as in FIG. 1 are the same or corresponding parts, so their explanation will be omitted.

The embodiment shown in Fig. 8 uses a multi-stage (three steps in this example) press molding equipment, and the sheet material shown in Fig. 1 is replaced with a tablet. In the first step, the pellet l8, which has been heated in advance to the heat distortion temperature range, is placed in the cavity between the upper die 1 and the lower die 1'. Set using a transfer device such as a robot. Thereafter, press molding is performed in the same manner as the first step in FIG. The second and third steps are also pressurized and shaped using the same method, but a robot or the like is suitable for transferring the lens.

According to the embodiment shown in FIG. 8, in addition to the same effects as the embodiment shown in FIG. It is effective for

Next, FIGS. 9 and 10 are schematic side views of a press molding apparatus equipped with an extruder according to still another embodiment of the present invention. In the figure, the same reference numerals as in FIG. 1 indicate equivalent parts.

The embodiment shown in FIGS. 9 and 10 omits the heating means for the sheet material 7 explained in the embodiment shown in FIG.
0 (30A) connected to the extruder 19. Therefore, the material formed into a sheet shape by the extruder 19,
That is, the sheet material 7 has upper and lower die IA, 1'A
When it enters the gap, it is in the heat deformation temperature range and can be easily shaped. Upper and lower die IA, 1'
The cavity shape of A is formed so that a predetermined lens shape can be obtained by one-stage press working.

In the embodiment shown in FIG. 9, the speed of the sheet material 7 extruded by the extruder 19 is set to be low enough to prevent large deflection from occurring due to the press forming time of the press forming apparatus 30. Even if deflection occurs, it is absorbed by the surplus material 20 between the lenses as the lens L moves after molding, and returns to its original state without deflection.

In the embodiment shown in FIG. 10, the sheet material 7 can be shaped regardless of the speed at which it is extruded from the extruder 19. Press molding device 3
0A is for press forming while moving in the same direction according to the sheet speed by the moving means 23.

The embodiment shown in FIGS. 9 and 10 is effective for lenses that do not require much optical performance, such as surveillance camera lenses, door lenses, and video camera finder lenses. Since there is no need for shaping in multiple stages, the manufacturing time is significantly shortened, making it an excellent method for providing inexpensive lenses.

Next, FIG. 11 shows 1 according to still another embodiment of the present invention.
FIG. 2 is a side view of a step-press type plastic lens manufacturing device. In the drawings, the same reference numerals as those in FIGS. 1 and 7 are the same parts as in the previous embodiment, so the explanation thereof will be omitted.

In the embodiment shown in FIG. 11, lenses are manufactured by only the first step of the embodiment shown in FIG. It is formed so that a predetermined lens shape can be obtained.

The sheet material 7 heated by the heaters 9, 9' is intermittently passed through the upper and lower dies IB, 1' by the transfer clamps 8, 8'.
It is transferred between B. After that, upper and lower dice IB, 1'
Along with the pressing operation H, the pressure in the cavity spaces 21 and 22 is reduced by the vacuum pump 24, and the pressing operation further progresses to mold a desired lens.

According to the embodiment shown in FIG. 11, the same effects as those of the previous embodiments shown in FIGS. 9 and 10 can be expected.

Of the above-mentioned embodiments, the embodiments shown in FIGS. 1 and 8 describe a manufacturing method and an apparatus that includes a three-stage press and obtains a predetermined lens shape through a three-stage press process. However, the present invention is not limited to this, and it is sufficient to adopt a plurality of press processes in which at least two sets of presses each consisting of an upper die and a lower die are provided.For example, a two-stage press, a four-stage press, etc. The choice can be made depending on the specifications of the lens and the required degree of lens accuracy.

As mentioned above, the one-stage press is effective for lenses that do not require optical performance, such as the embodiments shown in FIGS. 9, 10, and 11.

Further, in each of the above embodiments, a method and apparatus for manufacturing a plastic lens have been described, but the present invention is not limited to this, and can also be applied to the molding of optical parts such as plastic prisms and plastic mirrors. .

[Effects of the Invention] As described above, the present invention provides a method for manufacturing a plastic optical component that can form a lens with desired shape accuracy, shorten the molding time of the lens, and reduce the unit price of the lens. equipment can be provided.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of a plastic lens manufacturing apparatus according to an embodiment of the present invention, Fig. 2 is a cross-sectional view of a model explaining the die shown in Fig. 1, and Fig. 3 shows its pressurizing method. The sectional view of the model to be explained, Figure 4, shows the second model equipped with a cutter blade.
FIG. 5 is an enlarged sectional view of the die in the third step, FIG. 6 is a perspective view showing an example of a lens manufactured using the apparatus shown in FIG. 1, and FIG. 7 is an enlarged sectional view of the die in the third step. , FIG. 1 is a detailed sectional view showing the die structure, FIG. 8 is a schematic side view of a press molding apparatus of a plastic lens manufacturing apparatus according to another embodiment of the present invention, and FIGS. 9 and 10 are: FIG. 11 is a schematic side view of a press molding apparatus equipped with an extruder according to still another embodiment of the present invention, and FIG. A side view and FIG. 12 are schematic diagrams showing resin flow in a concave lens formed by conventional injection molding, and FIG. 13 is a plan view of a lens obtained by conventional four-cavity molding. 1, IA, IB, 2.3... Upper die, 1'1'
A, 1' B, 2', 3' --- Lower die, la
, 2 a, 3 a, 1' a, 2' a, 3' a
...Cavity surface, 7... Sheet material, 8, 8'...
- Transfer clamp, 9, 9'...heater, 13...cutter blade, 14...exhaust hole, 16...temperature adjustment means.

Claims (1)

[Scope of Claims] 1. A plurality of pressing steps for each die in which at least two or more sets of upper and lower dies facing each other are provided at intervals, and a plurality of pressing steps for each die used in the plurality of pressing steps. The cavity shape is sequentially changed for each die so that the optical component to be press-molded obtains a predetermined shape in the final pressing process, and the sheet-shaped plastic material to be press-molded is heated to a heat distortion temperature range. A method for producing a plastic optical component, which comprises transferring the plastic optical component between an upper die and a lower die in a first press step, and sequentially press-molding the same in each of a plurality of press steps to obtain a predetermined optical shape. 2. A plurality of pressing steps for each die in which at least two sets of upper and lower dies are provided at intervals, which face each other, and the cavity shape of the die used in these plurality of pressing steps is formed by press molding. Each die is sequentially changed so that the optical component to be pressed has a predetermined shape in the final pressing process, and the plastic component to be press-molded is heated to a heat distortion temperature range, and then multiple sets of upper and lower molds are formed. It is intermittently transferred between dies in the order of each pressing process, and the center of the cavity of the die and the optical axis of the preformed optical component are in contact with each other, and the optical component is press-formed axially symmetrically toward the outer shape of the optical component. A method of manufacturing a plastic optical component, characterized by sequential press molding to obtain a predetermined optical shape. 3. A means for transporting the sheet-like plastic material to be press-molded, a heating means for heating the sheet-like plastic material to a heat distortion temperature range, and at least two sets of presses each consisting of an upper die and a lower die facing each other are spaced apart from each other. The plural sets of presses in this press-molding apparatus sequentially change the cavity shape of each die so that the optical component to be press-molded obtains a predetermined shape in the final press. A manufacturing apparatus for plastic optical parts, characterized in that the apparatus is configured by: 4. At least two sets of presses each consisting of a means for transporting a preformed plastic material to be press-molded, a heating means for heating the plastic material to a heat distortion temperature range, and an upper die and a lower die facing each other. The plural sets of presses in this press forming apparatus sequentially adjust the cavity shape of each die so that the optical component to be press-molded has a predetermined shape in the final press. The plastic is configured such that the center of the cavity of the die and the optical axis of the preformed optical component are in contact with each other, and the plastic is press-molded axially symmetrically toward the outer shape of the optical component. Optical parts manufacturing equipment. 5. In either claim 1 or claim 2,
A method for manufacturing a plastic optical component, characterized by controlling the temperature of each die in a plurality of pressing steps to a temperature below a heat distortion temperature range, and performing press molding while exhausting air in a cavity and reducing pressure. 6. In either claim 3 or claim 4,
1. An apparatus for manufacturing a plastic optical component, wherein each die in the plurality of presses is provided with means for adjusting die temperature and depressurizing means for eliminating air within the cavity. 7. In either claim 3 or claim 6,
1. An apparatus for manufacturing a plastic optical component, characterized in that each die in a plurality of presses is provided with a cutter blade for separating a sheet-like plastic material and a molded lens. 8. Equipped with an extruder that delivers sheet plastic material to be press-molded, and a press device consisting of an upper die and a lower die facing each other, the cavity shape of the die is shaped into the predetermined shape of the optical component to be press-molded. A manufacturing device for plastic optical parts, characterized in that: 9. A means for transporting a sheet-like plastic material to be press-molded, a heating means for heating the sheet-like plastic material to a heat distortion temperature range, and a press device consisting of an upper die and a lower die facing each other, The press device is characterized in that the cavity shape of the die is formed into a predetermined shape of the optical component to be press-molded, and the die is equipped with a means for adjusting die temperature and a depressurizing means for eliminating air within the cavity. Manufacturing equipment for plastic optical parts.