JPH0570154A - Molding method for press lens - Google Patents

Abstract

PURPOSE:To ensure the title lens to be demolded after making a press molding of a lens material. CONSTITUTION:In the title method where a heated and softened lens material 3 is put to press molding using a mold made up of top force 1 and bottom force 2, the top and bottom forces differ in temperature from each other, and the press lens is demolded after it is cooled to the mold's temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a press lens, and more particularly to a method for molding a press lens which is capable of continuously manufacturing a glass press lens by pressing a lens material.

[0002]

2. Description of the Related Art As a method for molding a glass press lens of this type, the applicant of the present invention has previously filed Japanese Patent Application No. 58-7808.
There is a lens molding method proposed by Japanese Patent Laid-Open No. 59-203732. The lens molding method according to the present invention includes a step of previously smoothly processing a press surface of a lens material for molding, a step of heating the lens material after the processing to a predetermined viscosity, and a step of softening the lens material to the predetermined viscosity. The method includes a step of loading the lens material between the upper mold and the lower mold, and a step of press-molding the lens material with the upper mold and the lower mold, and the lens is molded by this step.

[0003]

However, the conventional lens molding method described above has the following drawbacks.
That is, after pressing and molding the lens material, in order to release the molded lens from the molding die, the upper mold and the lower mold were separated while the outer periphery of the lens was held by the holding member. When the lens is firmly fixed to the molding surface of the molding die, the lens is separated from the holding member, and there is a problem that the lower die descends while the lens is attached to the upper die. There is a problem that it becomes impossible to continuously manufacture optical elements.

The object of the present invention has been made by paying attention to the above-mentioned drawbacks, and molding of a press lens which can surely release the molded lens from the molding die after press molding the lens material. There is a way to provide.

[0005]

A method of molding a press lens according to the present invention is a method of molding a press lens by pressing a heat-softened lens material by a molding die composed of an upper mold and a lower mold. A temperature difference is provided between the lower mold and the lower mold, and the press lens is cooled to the temperature of the molding mold and then released from the mold.

[0006]

Since there is a temperature difference between the molds, the press lens is separated from the mold side having a low temperature during mold release so that the press lens adheres to the mold side having a high temperature.

[0007]

The present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows an example of a method of molding a press lens according to the present invention, in which (A) is a state diagram in the initial stage of molding, (B) and (D) are state diagrams in the latter half of the molding, and (C). ),
(E) is a state diagram immediately after mold release. Also, (A) →
The process of (B) → (C) is the behavior when the temperature of the upper mold 1 is set higher than the temperature of the lower mold 2, and (A) →
The process of (D) → (E) is the opposite case. When the lens material comes into contact with the mold, it is rapidly cooled to near the mold temperature and solidified [see (A)]. Then, when there is a temperature difference between the molding dies, the shrinkage of the glass near the molding surface of the high temperature mold lags behind the glass near the molding surface of the low temperature mold,
A slight concave warpage occurs in the press lens 3. As a result, a vacuum gap is created between the molding surface of the mold and the press lens, which makes it difficult to release the mold. The amount of this gap is 0.
Since it is about 1 μm or less and has a uniform shape, there is no problem in optical performance [see (B) and (D)]. After that, the press lens 3 is released from the mold having the low temperature and is suitably released from the mold. The press lens 3 attached to the mold of high temperature is released from the release member 4 or the edge of the lens mounting table 5.

The temperature difference between the molds is preferably in the range of 5 to 50 degrees. If it is less than 5 degrees, the above action and effect will not occur,
Further, when the angle is 50 degrees or more, the internal distortion of the lens becomes large and the shape accuracy of the press lens becomes poor, so that it cannot be put to practical use.

Next, an example of a press lens manufacturing apparatus to which the above-described press lens molding method of the present invention is applied will be described with reference to FIGS.
This will be described with reference to FIG. 2 is a plan view showing an outline of the press lens manufacturing apparatus, and FIG. 3 is an enlarged sectional view taken along the line AA in FIG. A press lens manufacturing apparatus 9 to which the press lens molding method of the present invention is applied,
As shown in FIG. 2 and FIG. 3, the heating furnace 10 and the slow cooling furnace 1 are arranged in parallel on both sides of the press molding device 15 in between.
1, the heating furnace 10 and the slow cooling furnace 11, the gob (glass lump) carrier 12 and the lens carrier 13 are placed at equal intervals, respectively, and the transport caterpillar 14a is driven intermittently by the drive gear 33. , 14b
A final heating heater section 16 and a slow cooling start heater section 17, which are respectively provided between the molding apparatus 15 and the outlet of the heating furnace 10 and the inlet of the slow cooling furnace 11, and the gob carrier 12 and the lens carrier 13. The molding device 15 and the gob carrier carrying arm 18 and the lens carrier carrying arm 19 for carrying between the carrying caterpillars 14a and 14b respectively constitute a main part.

As shown in FIG. 3, the press molding apparatus 15 comprises an immovable upper die 20 and a movable lower die 21, and the apparatus cover 22, the final heating heater section 16 and the slow cooling start heater section 17 are provided. It is integrated. As shown in FIG. 4, the gob carrier 12 has a ring shape and is slightly (about 0.1 mm) larger than the outer diameter of the press gob 26 (see FIGS. 2 and 3) near the lower portion of the inner peripheral surface. A gob mounting step portion 24 having an inner diameter is provided, and the gob 2 is provided above it.
A relief portion 25 having a larger diameter is provided so that 6 can be easily removed. Further, at the lower part of the gob carrier 12, there is a through hole 27 formed in the gob transport caterpillar 14a.
A fitting portion 29 having an outer diameter that allows a loose fitting is provided (see FIG. 3), and a flange 28 that serves as a catching portion at the time of conveyance is provided at the upper end portion. In addition,
A through hole 23 through which the lower mold 21 is inserted is formed in the center of the lower part.

As shown in FIG. 5, the lens carrier 13 is bowl-shaped and has an inner bottom surface which is a lens holding portion 30 for holding a press lens 34 (see FIGS. 2 and 3). A fitting portion 31 and a flange 32, which are similar to those of the gob carrier 12, are provided in the portion. The gob carrier 12 and the lens carrier 13 have the press gob 26 and the press lens 34 mounted therein, and are transported by the transport caterpillars 14a and 14b.

The gob carrier carrying arm 18 carries the gob carrier 12 on the gob carrying caterpillar 14a between the upper and lower dies of the press molding apparatus 15.
A drive device 35 having a base end portion directly connected thereto drives the transport caterpillar 14a horizontally in a direction perpendicular to the transport direction and also in the vertical direction. Then, as shown in FIG. 6, two parallel pressing plates 36a and 36b, which are cut in a fork-like shape at the center of the front end so as to sandwich the flange 28 of the gob carrier 12, are attached to the front end 18a of the mounting screw 37. Installed by.

The lens carrier carrying arm 19 comprises:
The press lens 34 molded by the press molding device 15 is dropped into the lens carrier 13 and the lens carrier 13 is transported onto the lens transport caterpillar 14b. A drive device 38 that performs the same driving operation as the drive device 35 of the arm 18 is connected to the base end portion, and the tip end portion 19a has a flange 32 of the lens carrier 13 at the tip end center portion as shown in FIG. A support 39 cut like a fork so that it can be picked up from below.
At the upper part of the lens dropping claw 40, the central part of the tip is tapered in opposition to the supporting part 39.
Are attached by attachment screws 41.

Next, the operation of the press lens manufacturing apparatus constructed as described above will be explained. First, as shown in FIG. 2, the transport caterpillar 14a exposed outside the inlet of the heating furnace 10 is punched at equal intervals. The gob carrier 12 having the press gob 26 mounted on the gob mounting step portion 24 is fitted and mounted in the provided through hole 27 (see FIG. 3). Next, the press gob 2 placed on the gob carrier 12
6 is heated and conveyed by the caterpillar 14a for gob conveyance which moves intermittently in the direction of arrow b so that the inside of the heating furnace 10 is saturated to reach a temperature several tens of degrees lower than a predetermined molding temperature during pressing. .. Then, when it reaches the entrance to the final heating heater section 16 of the heating furnace 10, the gob carrier 12 reaching the entrance reaches the gob carrier carrying arm 18.
Thus, the inside of the final heater portion 16 is conveyed toward the inside of the press molding device 15 in a direction perpendicular to the traveling direction of the transport caterpillar 14a.

That is, the carrying arm 18 moves horizontally from the standby position (the position shown in FIG. 2) toward the gob carrier 12 on the carrying caterpillar 14a by the driving device 35 thereof, and the pushing plate at the tip thereof. The flange 28 of the gob carrier 12 is held by 36a and 36b. Then, after the gob carrier 12 is lifted from the transport caterpillar 14a by the drive device 35, it is moved to the central portion of the final heating heater portion 16 and temporarily stopped at the central portion for a few minutes, and The temperature of the gob 26 on the gob carrier is raised to a predetermined molding temperature.

Here, the gob carrier 12 on which the press gob 26 having reached a predetermined temperature is placed is then conveyed to the central portion between the upper die 20 and the movable lower die 21 in the press molding apparatus 15. It Further, in synchronization with this, the lower mold 21 starts to rise, and the press gob 26 is pushed up from below the gob carrier 12 through the through hole 23. As a result, the gob 26 is pressed by the upper mold 20 and the lower mold 21 to be molded into the press lens 34. Then, after pressing for 10 seconds, the lower mold 21 descends to complete the pressing.

At this time, since the upper mold 20 is controlled to have a temperature (10 degrees) higher than that of the lower mold 21, the press lens 34 is separated from the lower mold 21 by the temperature difference and the upper mold 2 is pressed.
Stick to 0. After the press is completed, the above-mentioned carrying arm 18
Returns the emptied gob carrier 12 horizontally to the original position on the transfer caterpillar 14a in the heating furnace 10, and then returns to the initial standby position (position in FIG. 2).

On the other hand, the lens carrier carrying arm 1 described above.
Reference numeral 9 indicates a slow cooling furnace 11 driven by its driving device 38 from the standby position in FIG. 2 in synchronization with the completion of molding of the press lens 34.
The lens carrier 13 on the lens-conveying caterpillar 14b waiting in advance at the entrance to the slow cooling start heater section 17
The support portion 39 at the tip end thereof is made to enter below the flange 32 of the lens carrier 13. Then, by the driving device 38, the lens carrier 13
And move it horizontally to move the press molding device 15
It is transported to the lower part of the upper mold 20 inside. As shown in FIG. 8, the transport position at this time is a position where the press lens 34 is sandwiched between the lens carrier 13 and the lens dropping claw 40 in the middle.

From this state, when the carrying arm 19 is pulled down in the direction of the arrow c by the driving device 38, the taper-shaped lens dropping claw 40 and the upper die 20 at the tip of the arm 19 are attached. Pressing lens 3
4 gradually contacts and is dropped into the lens holding portion 30 of the lens carrier 13. Next, the lens carrier 13 holding the press lens 34 is returned to its original position in the annealing furnace 11 by the lens carrier carrying arm 19 through the slow cooling start heater unit 17, and the carrying arm 19 returns to the initial standby position. .. The press lens 34 is gradually cooled while passing through the inside of the slow cooling start heater unit 17, and after being transferred onto the transport caterpillar 14b, the press lens 34b.
While being transported in the slow cooling furnace 11 by intermittent movement, it is further cooled, and at the outlet of the slow cooling furnace 11, the track 1
It is taken out from the lens carrier 13 on 4b.

After the above-described series of operations is completed, the transport caterpillars 14a and 14b are moved to the next gob carrier 1.
The following molding operation is performed by intermittently moving 2 and the lens carrier 13 in the directions of arrows b and d (see FIG. 2), respectively.

By applying the press lens molding method of the present invention as described above, a press lens manufacturing apparatus capable of efficiently and automatically molding and manufacturing a glass press lens only by providing a gob carrier and a lens carrier having a simple structure. Can be provided.

[0022]

As described above, according to the method for molding a press lens of the present invention, the press lens after molding can be reliably
Since the mold can be released from one of the molds, the optical element can be continuously molded, which allows automation of the press lens manufacturing apparatus and the like.

[Brief description of drawings]

FIG. 1 is a process drawing showing an example of a method for molding a press lens of the present invention.

FIG. 2 is a schematic plan view showing an example of a press lens manufacturing apparatus to which the press lens molding method of the present invention is applied.

FIG. 3 is an enlarged sectional view taken along the line AA in FIG.

FIG. 4 is an enlarged cross-sectional view of a gob carrier used to convey a press gob.

FIG. 5 is an enlarged cross-sectional view of a lens carrier used to convey a press lens.

FIG. 6 is an enlarged perspective view showing the configuration of the tip portion of the carrying arm of the gob carrier.

FIG. 7 is an enlarged perspective view showing the configuration of the distal end portion of the carrying arm of the lens carrier.

FIG. 8 is a cross-sectional view of essential parts showing a state of the press lens at the time of mold release.

[Explanation of symbols]

 1 ……………… Upper mold 2 ……………… Lower mold 3 ……………… Lens material (press lens)

Claims (1)

[Claims] 1. A method of press-molding a heat-softened lens material by a molding die composed of an upper die and a lower die to form a press lens, wherein a temperature difference is provided between the upper die and the lower die, and the press lens is A method of molding a press lens, which comprises releasing the mold after cooling to the temperature of the mold.