JPH06171959A - Production of optical element - Google Patents

Abstract

PURPOSE:To form the optical element having a prescribed shape with good accuracy. CONSTITUTION:A fused optical glass blank material 13 is made to flow out into a forming chamber 1 and is cut where the blank material arrives at the front end of a plunger die 16. A plunger die 19 is then moved onto the shaft of the forming chamber 10. The plunger die 18 is thereafter lowered to press a gob 21. A movable shaft 8 and vertically split dies 7 are retreated toward the right, by which the forming chamber 10 is opened and the plunger dies 16, 18 and a parting arm 20 are moved rightward while the optical element 22 is held therebetween, by which the optical element is parted from the vertically split dies 2, 7. The plunger die 16 is thereafter lowered and the parting arm 20 is lowered cooperatively therewith, by which the optical element 22 is parted from the plunger die 18. The optical element 22 is thus obtd. Both end faces of the optical element 22 are worked to a desires shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical element.

[0002]

2. Description of the Related Art Conventionally, a molding die for pressurizing a glass material to form an optical element having a polygonal prism shape is, for example, Shoukai 62.
There is one disclosed in Japanese Patent Laid-Open No. 191837. This molding die is a molding die for molding an optical element 30 having an optical function surface which is three planes, and its schematic configuration diagram is shown in FIG.
Shown in.

As shown in FIG. 5, the molding die 24 is a frame die 2.
5, a lower die 26 of a quadrangular prism that is provided in the frame die 25 and has a trapezoidal cross section, and a middle die 28 of a triangular prism that is placed on the lower die 26 and forms a lower die part 27 together with the lower die 26. , A middle mold 28 and a lower mold 26, and an upper mold 29 arranged to face each other.

According to the molding die disclosed in Japanese Utility Model Laid-Open No. Sho 62-191837, the molding surface of the lower die 26 is extended and the middle die 28 is mounted on the extended portion. The boundary with the lower mold 26 is the optical element 30 shown in FIG.
The ridgeline 30a is to be formed.

When molding is performed with the molding die 24 having the above structure, the lower die portion 2 formed by the lower die 26 and the middle die 28.
The glass material is supplied to 7, and the upper die 29 press-molds this glass material. When the glass material is press-molded by the upper mold 29, the first optical function surface 30b of the optical element 30 shown in FIG.
0c is transferred to the molding surface of the middle mold 28, and the third optical function surface 30d is transferred to the molding surface of the upper mold 29.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the mold 24 disclosed in Japanese Patent No. 191837,
Since the glass material is press-molded by the upper mold 29 whose molding surface is the molding die that transfers the optical function surface 30d of the optical element, the ridge line 30a and the optical function surface (the third face) located at the position opposite to the ridge line 30a are formed. Since it is difficult to determine the distance to the optical function surface 30d) of the above, it becomes difficult to form an optical element having a predetermined shape.

The present invention has been made in view of the above conventional problems, and an object thereof is to provide an optical element manufacturing method capable of molding an optical element having a predetermined shape.

[0008]

In order to solve the above-mentioned problems, the present invention, when manufacturing an optical element, comprises a plurality of molding dies each having a molding surface for molding an optical functional surface of the optical element, and an optical element. A plurality of molding dies having molding surfaces for molding surfaces other than the optical function surface of the element are combined so that the molding surfaces face each other, and a glass material is supplied between the molding dies, and the optical element The glass material is press-molded by at least one of the molding dies having a molding surface for molding the surface other than the optical function surface.

[0009]

According to the above means, the molding die that contributes to the molding of the optical functional surface is fixed at the time of molding, and the glass material is pressed by the molding die that does not contribute to the molding of the optical functional surface. Can be properly molded,
An optical element having a predetermined shape can be molded.

[0010]

Embodiment 1 FIGS. 1 (a) to 1 (f) are vertical sectional views showing a molding process of this embodiment, and FIG. 2 is a cross-sectional plan view showing a combined state of molding dies used in this embodiment. In this embodiment, FIG.
As shown in, vertical split mold 1 that does not contribute to the molding of the optical functional surface
The two vertical split molds 2 and 3 having the molding surface for molding the optical function surface are fixed by fixed shafts 4, 5 and 6, respectively. Further, the remaining one vertical split mold 7 on which a molding surface for molding the optical function surface is formed is moved horizontally by the movable mold 8 (left and right in FIG. 2) so as to contact and separate from the vertical split molds 1, 2, 3. It is provided so as to be movable (in a direction inclined by about 10 ° from the direction). A space surrounded by these vertical split molds 1, 2, 3, 7 becomes a molding chamber 10. Vertical split type 1, 2, 3,
A heater 9 is attached to 7 so that it can be heated.

On the other hand, above the molding die, as shown in FIG.
As shown in ~ (c), the crucible 11 is arranged,
The crucible 11 is configured to melt the optical glass material 13 and allow the molten glass to flow out from the orifice 14. Below the orifice 14, a shear 15 is arranged so that the molten glass that has flowed out can be cut. Here, the orifice 14 is provided on the axis of the molding chamber 10, and is formed smaller than the cross section of the size inscribed in the cross section of the molding chamber 10.

Below the molding chamber 10, there is disposed a pressing die 16 which is a molding die for molding a molding surface other than the optical function surface. The pressing die 16 has a flat tip and a cross-sectional shape that is 80% smaller than the cross-sectional shape of the molding chamber 10 in length. The push die 16 is configured to be movable in the horizontal (left and right) direction. Further, a heater 17 is provided on the outer periphery of the lower portion of the pressing die 16 so that it can be maintained at a predetermined temperature.

A pressing die 18, which is a molding die for molding a molding surface other than the optical function surface, is constructed so as to be movable in the horizontal direction (left-right direction) in conjunction with the crucible 11 and the shear 15, and FIG. ) Position (withdrawal position) and molding chamber 1
It is configured so that it can move to and from the 0 position on the axis. Further, the pressing die 18 is also configured to be movable in the vertical direction and capable of pressing the molten glass. Push mold 1
A heater 19 is provided on the outer periphery of 8 so that it can be maintained at a predetermined temperature. Release arm 20
Can enclose the lower end of the pressing die 18 and are provided so as to be movable up and down.

With the molding apparatus having such a configuration, FIG.
An optical element was manufactured as shown in (a) to (f).
First, as shown in FIG. 1 (a), the optical glass material 13 melted in the crucible 11 is made to flow out from the orifice 14, and is made to flow out into the molding chamber 10 to make the pressing die 16 as shown in FIG. 1 (b). When it reached the tip, it was cut by the shear 15. Next, as shown in FIG. 1C, the pressing die 18 was moved along with the crucible 11 and the shear 15 onto the axis of the molding chamber 10. Then, as shown in FIG.
8 was lowered and the gob 21 was pressed. At this time, the pressing dies 16, 18 and the vertical split dies 1, 2, 3, 7 shown in FIG. Immediately after that, nitrogen was blown to the mold through the blow pipe 23 to cool the mold.

Next, as shown in FIG. 1 (e), the movable shaft 8
By retreating the vertical split mold 7 to the right, the molding chamber 10 is opened, and the pressing molds 16 and 18 and the mold release arm 20 are opened.
Was moved to the right with the optical element 22 sandwiched, and released from the vertical split molds 1, 2, 3. After that, the push die 16 was lowered, and the release arm 20 was lowered in conjunction with this, and the optical element 22 was released from the push die 18 to obtain the optical element 22. Optical element 22 thus obtained
Both end faces were processed into a desired shape to obtain a final optical element.

When a prism having a material of SF11 and a cross section of a right triangle was formed by the above method,
An optical element having good surface accuracy and angle accuracy was obtained.

[0017]

[Embodiment 2] FIGS. 3 (a) to 3 (e) are vertical sectional views showing the molding process of this embodiment, and FIG. 4 is a cross-sectional plan view showing a combined state of the molding dies used in this embodiment. In this embodiment, FIG.
As shown in FIG. 3, the three vertical split molds 1, 2 and 3 each having the molding surface for molding the optical function surface are fixed shafts 4, 5, respectively.
It is fixed by 6. Further, the remaining one vertical split mold 7 on which a molding surface for molding the optical function surface is formed is horizontally moved by the movable mold 8 so as to be able to contact and separate from the vertical split molds 1, 2, 3 (left and right in FIG. 4). Movably). A space surrounded by the vertical split molds 1, 2, 3, 7 becomes a molding chamber 10 having a square cross section. A heater 9 is attached to each of the vertical split molds 1, 2, 3, and 7,
It can be heated and kept at a predetermined temperature.

Below the molding chamber 10 constituted by the vertical split molds 1, 2, 3, and 7, a pressing die 31 which is a molding die for molding a molding surface other than the optical function surface is provided at the lower end of the molding chamber 10. The pressing die 31 is arranged so that its tip is located in the vertical direction. A heater 32 is provided on the outer periphery of the pressing die 31 so that the pressing die 31 can be heated to a predetermined temperature. Push mold 31
The cross section of is similar to the cross section of the molding chamber 10 and is formed smaller than the cross section of the molding chamber 10. Further, the pressing die 31 is
It is provided coaxially with the molding chamber 10. Above the molding chamber 10, the optical glass rod 33 having a diameter smaller than the diameter of the circle coaxial with the molding chamber 10 and having a cross section inscribed in the cross section of the molding chamber 10 is heated by the heater 34 to a temperature at which it is softened. It is provided.

The shear 35 is a softened optical glass rod 33.
It has a function of a pair of pressing dies when it is pressed by the pressing die 31, and is formed of a material and a size capable of withstanding the pressure.

With the molding apparatus having such a configuration, as shown in FIG.
An optical element was manufactured as shown in (a) to (e).
First, as shown in FIG. 3A, the vertical split molds 1, 2, 3, 7
Was heated to around the softening point of the optical glass material by the heater 9, and the optical glass rod 33 was heated to above the softening point of the optical glass material by the heater 34. Next, as shown in FIG. 3B, the softened optical glass rod 33 was supplied into the molding chamber 10 and stopped when it came into contact with the tip of the pressing die 31.
At this time, the temperature of the pressing die 31 was heated by the heater 32 to a temperature near the glass softening point of the optical glass material.

Next, as shown in FIG. 3 (c), the shear 3
5, the optical glass rod 33 is cut, and the shear 35 is cut there.
Was left as it was. At this time, vertical split type 1, 2,
The temperatures of 3 and 7 were heated to a temperature near the glass transition point of the optical glass material by the heater 9. After that, as shown in FIG. 3D, the pressing die 31 is pushed upward to move the molding chamber 10
The optical glass rod 33 inside was pressed. At this time, an inert gas was blown from the blow pipe 36 to the mold to cool the mold.

After molding, as shown in FIG. 3 (e), the vertical split molds 3 and 7 are retracted by the movable shafts 6 and 8 to move the shear 35.
Was opened, the pressing die 31 was moved to the upper right front direction, and released. At this time, the molded optical element 37 is in a state of being bitten by the pressing die 31 by the portion protruding into the gap between the pressing die 31 and the molding chamber 10. Therefore, the optical element 37 can be released and conveyed by the movement of the pressing die 31. The prism having the shape of a quadrangular prism formed by such a method was cut at three positions along with the end face, processed into a desired thickness, and four prisms were obtained by molding once.

According to the manufacturing method of the present embodiment as described above, columnar optical elements can be continuously obtained from a glass rod, and a large number of optical elements can be obtained by molding once. It was possible to manufacture at low cost.

[0024]

As described above, according to the optical element manufacturing method of the present invention, the glass material is press-molded by the molding die which is the molding surface for transferring the surface other than the optical function surface of the optical element. Since the distance between the ridgeline and the optical function surface located at a position facing the ridgeline can be reliably determined, an optical element having a predetermined shape can be molded.

[Brief description of drawings]

FIG. 1 is a process chart showing a manufacturing process according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional plan view showing a vertically split type combined state of the first embodiment.

FIG. 3 is a process drawing showing the manufacturing process of Example 2 of the present invention.

FIG. 4 is a cross-sectional plan view showing a vertically split type combined state of the second embodiment.

FIG. 5 is a schematic configuration diagram showing a conventional molding die.

FIG. 6 is a perspective view of an optical element obtained by a conventional molding die.

[Explanation of symbols]

 1, 2, 3, 7 Vertical split type 10 Molding room 13 Optical glass material 16, 18, 31 Push type 22, 37 Optical element 33 Optical glass rod

Claims (1)

[Claims] 1. A plurality of molding dies having a molding surface for molding an optical functional surface of an optical element and a plurality of molding dies having a molding surface for molding a surface other than the optical functional surface of the optical element. , The molding surfaces are combined so as to face each other, a glass material is supplied between the molding dies, and a molding surface for molding a surface other than the optically functional surface of the optical element is formed, A method for manufacturing an optical element, comprising press-molding the glass material with at least one mold.