JPH0443853B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is directed to an optical element for manufacturing a press lens having high surface precision and surface roughness by only press molding without the need for grinding, polishing, etc. Regarding molding equipment.

[Prior Art] Conventionally, as a molding apparatus for this type of optical element,
For example, an apparatus used to carry out the method disclosed in Japanese Patent Laid-Open No. 118641/1988 is known. In this device, as shown in FIG. 5a, first, a ring-shaped conveying member 2 carrying a glass material 7a thereon is carried into the sleeve 4 through an inlet 5 of the sleeve 4, and a coaxial A glass material 7a is provided so as to be located between the upper and lower molds 1 and 3 which are slidably guided thereon. In this way, the glass material 7a is attached to the sleeve 4.
FIG. 5b shows the state set in the middle.

Next, as shown in FIG. 5c, the upper mold 1 and the lower mold 3 are lowered and raised, and the ring-shaped conveying member 2
The glass material 7a placed on the glass material 7a is press-molded to form a press lens 7. At this time, the outer diameter of the press lens 7 is the same as that of the ring-shaped conveying member 2.
determined by the inner diameter of Thereafter, as shown in FIG. 5d, the upper mold 1 and the lower mold 3 are raised and lowered to release the mold. Then, as shown in FIG. 5e, the molded press lens 7 is mounted and supported by the ring-shaped conveying member 2 and is transferred to the outside of the sleeve 4.

[Problems to be Solved by the Invention] However, the above conventional apparatus has the following problems.

That is, since the glass material 7a is press-molded while being placed on the mounting surface 2a of the ring-shaped conveyance member 2, the glass material 7a and the ring-shaped conveyance member 2 are molded as if they were integrated, and the molding Later, the press lens 7 and the ring-shaped conveyance member 2 come into close contact or tight fit. For this reason,
There was a problem in that it was extremely difficult to release the press lens 7 from the ring-shaped conveyance member 2, and the workability during release was poor. On the other hand, in order to solve this problem, it is possible to apply a mold release agent to the inner surface of the ring-shaped conveying member 2, but the influence of the mold release agent on quality becomes a problem, and furthermore, the mold release agent There was a problem in that post-work was required to remove the .

The present invention was made with attention to such problems, and it maintains good quality without using a mold release agent.
It is an object of the present invention to provide an optical element molding apparatus with good workability, which allows a press lens to be easily taken out from a ring-shaped conveyance member.

[Means for Solving the Problems] The present invention is a method of forming an optical element by holding a heat-softened glass material in a glass conveying member and press-molding it with a mold consisting of an upper mold and a lower mold disposed coaxially facing each other. In the apparatus, a collar that is slidably fitted to the molding portions provided on the upper mold and the lower mold through elastic bodies and clamps and holds the conveying member;
The glass material held by the conveying member is separated from the conveying member by the lower die which can be press-molded.

[Function] According to the present invention, when press-molding a press lens, the glass material is pushed up by the lower mold,
The glass material and the conveying member are in a non-contact state.

[Example] Hereinafter, an example of the present invention will be described in detail using the drawings.

(First Embodiment) FIG. 1 is a sectional view showing a first embodiment of an optical element molding apparatus according to the present invention.

In the figure, numeral 10 indicates a sleeve, and inside this sleeve 10 there is an upper mold 11 fixed to the sleeve 10, and a lower mold provided slidably on the sleeve 10 and movable by a drive device (not shown). 12
are disposed coaxially and facing each other, and a lower mold 12 is provided so as to be able to approach and separate from the upper mold 11.

The upper mold 11 and the lower mold 12 are provided with protruding molding parts 11b and 12b having molding surfaces 11a and 12a formed at their tips corresponding to the desired lens surface shape. The molding parts 11b and 12b have an upper mold 11
Elastic members 13 and 14 such as coil springs attached to the lower die 12 are wound around the lower die 12, and a conveying member 16 on which a glass material 15, which is the object to be formed, is placed and held is clamped and held (see Fig. 2). An upper mold collar 17 and a lower mold collar 18 are supported by the elastic members 13 and 14, respectively, and are slidably provided. Note that the elastic members 13 and 14 are
It can be implemented by constructing an elastic member 21 formed of a ring-shaped elastic body as shown in FIG.

The upper die collar 17 is provided with a recessed support portion 17a for the elastic member 13, and also has a recessed support portion 17a for the elastic member 13.
A contact surface 17b that contacts 6 is formed. Further, a fitting portion 17c is formed between the contact surface 17b and the molded portion 11b that communicates with the support portion 17a. On the other hand, similarly to the upper mold collar 17, the lower mold collar 18 also includes a support portion 18a, a contact surface 18b, and a fitting portion 18.
c is formed.

On the side surface (part of the outer peripheral surface) of the sleeve 10,
Glass material (preform) 15 as a molded object
Alternatively, a carry-in port 10a is formed for carrying the conveyance member 16 holding the glass material 14 into and out of the sleeve 10. Furthermore, a dome-shaped heating furnace 19 is integrally fixed to the side surface of the sleeve 10 and communicates with the inside of the sleeve 10 through the entrance 10a. 20 is a heater provided in the heating furnace 19.

The conveying member 16 is approximately ring-shaped (or cylindrical)
As shown in Fig. 1, the lower mold 1
The upper die 11 provided in the sleeve 10 is carried into and out of the sleeve 10 via the heating furnace 19 and the carry-in port 10a, supported by a transfer arm 22 that is operated in a direction perpendicular to the direction of movement of the and lower mold 1
It is now located between the two. This conveying member 16 has a flange portion (a flange portion) on the outer circumferential portion of the upper end of the main body portion 16a that engages with an engagement step portion 22a formed at the top of the distal end of the conveying arm 22 to lock the conveying member 16 to the conveying arm 22. A collar portion) 16b is formed. Further, a storage part 16c for storing the glass material 15 is recessed inside the upper end of the main body part 16a, and a storage part 16c is provided below the storage part 16c.
6a to form a stepped portion 16d;
A through hole 16e that can pass through the lower mold 12 is provided in the main body 16.
It is opened on the lower surface of a. This stepped portion 16d includes the glass material 15 and the press lens 1 after press molding.
It is formed as a mounting surface on which 5a is mounted. The storage section 16c prevents the glass material 15 and the press lens 15a from shifting during transportation and press molding, and is formed to have a diameter slightly larger (for example, about 0.1 mm) than the outer diameter of the press lens 15a. A gap is formed between the outer peripheral surfaces of the glass material 15 and the press lens 15a and the inner wall surface of the storage portion 16c. On the other hand, supporting the conveying member 16,
The conveying arm 22 to be conveyed has a guide hole 22b communicating with the engagement step part 22a on the lower surface 2 of the conveying arm 22.
2c, and is formed so that the main body portion 16a of the conveying member 16 can be slidably inserted into the guide hole 22b, and the lower mold collar 18
When the carrier member 16 is pushed up, the carrier member 16 can move upwardly relative to the carrier arm 22.

Next, a case where an optical element is press-molded using the optical element molding apparatus having the above configuration will be described.

First, as shown in FIG.
6a to support the conveying member 16 on the conveying arm, and also move the glass material 15 onto the conveying member 16.
is placed on the stepped portion 16d. And heating furnace 19
Inside, the glass material 15 is heated to a predetermined temperature and softened. After heating and softening, the glass material 15 and the conveying member 16 are conveyed into the sleeve 10 through the entrance 10a provided in the sleeve 10 by driving the conveying arm 22,
The glass material 15 and the conveying member 16 are placed in both upper and lower molds 1.
It stops at a predetermined position between the molding surfaces 11a and 12a of Nos. 1 and 12. Thereafter, the lower mold 12 is raised by driving a drive device (not shown). As the lower mold 12 rises, the lower mold collar 18 also rises, and the contact surface 18b of the lower mold collar 18 contacts the lower end surface of the conveying member 16. Then, as it continues to rise, the lower color 1
8, the conveying member 16 is pushed up above the conveying arm 22 and approaches the upper die collar 17. Then, the upper end surface of the conveying member 16 comes into contact with the contact surface 17b of the upper die collar 17. After that, when the lower mold 12 continues to rise, the conveying member 16 moves both the upper and lower collars 17,
18 and is held in a neutral state (balanced state) by the elastic action of the elastic members 13 and 14, and the conveying member 16 is prevented from rising, and the molding part 12b of the lower mold 18 is raised to allow the conveying member 16 to penetrate. Hole 1
6e and presses the glass material 15 with the molding surface 12. At this time, the glass material 1 attached to the stepped portion 16d of the conveying member 16 during heating and softening in the heating furnace 19
5 is press-molded by the molding surface 11a of the upper mold 11 and the molding surface 12a of the lower mold 12 after releasing the adhesion of the glass material from the conveying member 16 and press-molding the glass material into a predetermined shape. It becomes 15a. Here, the press lens 15a during press molding
is press-molded while being prevented from being misaligned by the storage section 16a of the conveying member 16, and with a gap provided between the outer peripheral surface of the press lens 15a and the inner wall surface of the storage section 16c.

After the press molding is completed, the upper and lower parts 12 are lowered to the positions before being raised, and the elastic force of the elastic member 13 is applied to the upper mold collar 17 of the upper mold 11 to drop the press lens 15a and remove the stepped portion of the conveying member 16. 16
Place and hold on d. In order to release the press lens 15a and the upper mold 11, a release member is carried in through the entrance 10a of the sleeve 10, and the outer peripheral portion 15b of the press lens protruding from the outer periphery of the molding surface 11a is removed by the release member. It can be carried out in a configuration in which it is pressed from above.

Thereafter, the transport arm 22 is moved, the press lens 15a and the transport member 16 are pulled out from inside the sleeve 10, and after a predetermined cooling process, the press lens 15a is taken out from the transport member 16.

As described above, according to the molding apparatus of this embodiment,
The glass material can be lifted up from the mounting surface (step part) of the conveyance member and press-molded, and during press-forming, it is possible to prevent the glass material and the press lens from adhering to the conveyance member. Furthermore, the housing part for the conveying member is formed to have a larger diameter than the outer diameter of the press lens, and a gap is provided between the conveying member and the press lens so that the press lens can be held on the conveying member. The press lens and the conveyance member do not come into close contact or tight fit. Therefore, the press lens can be taken out from the conveying member very easily.

(Second Embodiment) FIG. 4 shows a second embodiment of the optical element molding apparatus according to the present invention. In this embodiment, only the shape of the lower die collar that clamps the conveying member 16 is It is formed with a different structure from the lower mold collar of the embodiment, and the other structure is the same as that of the first embodiment, so some parts are omitted from the illustration and the same parts are given the same numbers. The explanation will be omitted.

Lower mold collar 2 used to implement the device of this example
5 is a fitting part 25 of the main body part 16a of the conveying member 16
a is formed on the contact surface 17b of the collar 25.

In the apparatus of this embodiment as well, a press lens can be press-molded in the same manner as in the first embodiment.

According to this embodiment, since the conveying member and the collar are positioned via the fitting portion, it is possible to precisely align the conveying member and the molding surface of the lower die, and
The same functions and effects as in the first embodiment can be achieved.

[Effects of the Invention] As described above, according to the optical element molding apparatus of the present invention, the lower die pushes up the glass material and press-forms the glass material while separating it from the surface on which the glass material is placed on the conveying member. In addition, since the glass material and molded lens are held on the conveying member while forming a gap between the glass material and the side surface of the molded lens, there is no need for a mold release agent and the pressed lens can be maintained in good condition. It can be easily taken out from the ring-shaped conveying member, improving work efficiency.

[Brief explanation of drawings]

1 and 2 show a first embodiment of the optical element molding apparatus of the present invention, FIG. 1 is a longitudinal sectional view of the apparatus before press forming, and FIG. 2 is a longitudinal sectional view of the apparatus during press forming. FIG. 3 is a cross-sectional explanatory view showing another elastic member, and FIG. 4 is a cross-sectional view showing a conveying member in the second embodiment of the optical element molding apparatus of the present invention. 5a, b, c, d and e are explanatory diagrams of the prior art. 10... Sleeve, 11... Upper mold, 11b...
Molding part, 12... Lower mold, 12b... Molding part, 1
3, 14, 21...Elastic member, 15...Glass material, 15a...Press lens, 16...Transporting member, 17...Upper mold collar, 18, 25...Lower mold collar, 22...Transporting arm.

Claims (1)

[Claims] 1. In an optical element molding apparatus that holds a heated and softened glass material in a glass material conveying member and press-forms it using a mold consisting of an upper mold and a lower mold disposed coaxially facing each other, a a collar that is slidably fitted to each of the molded parts via an elastic body and that clamps and holds the conveying member;
An apparatus for molding an optical element, comprising the lower mold capable of press-molding a glass material held by the conveying member, separated from the conveying member.