JPH05330832A - Method for molding calchogenide glass lens - Google Patents

Abstract

(57) [Summary] [Purpose] It is an object of the present invention to provide a method capable of inexpensively molding an infrared transmitting lens having different curvature radii of opposing optical mirror surfaces with a small number of molding steps with high precision and high yield. A first molding die 1 having an optical mirror surface 2, a second molding die 6 having an optical mirror surface 7 having a radius of curvature different from that of the optical mirror surface 2, and a barrel mold 12 for determining the thickness of a lens. The chalcogenide glass piece 11 is put in the space surrounded by and the pressure is applied while keeping the optical mirror surfaces 2 and 7 of the first and second molding dies at different temperatures. ， High yield and low cost molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of molding an infrared-transparent chalcogenide glass lens.

[0002]

2. Description of the Related Art A conventional infrared transmitting lens is manufactured by polishing a silicon single crystal. On the other hand, a conventional oxide glass lens has been molded by the method shown in FIG. 4 (for example, Japanese Patent Publication No. 4-32008). In the figure, 20 is a lower mold, 21 is an upper mold, 22 is a bush, 23 is an optical surface, 24 and 25 are mold carriers, 26 is an induction heating coil, 27 is a frame, 28 is a glass preform, and 29.
Is a thermocouple, and the glass lens is formed by pressurizing the glass lens preform 28 with the induction heating coil 26 and applying pressure with the lower mold 20 and the upper mold 21. At this time, the upper and lower portions of the glass lens preform 28 were kept at the same temperature.

[0003]

However, the method of polishing and forming a silicon single crystal has a problem that the number of steps is large and the cost is high. Further, in the above-mentioned conventional method for molding oxide glass, it has not been possible to mold glass lenses having different optical mirror surfaces having different radii of curvature with high accuracy and high yield.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a method capable of molding with high precision, high yield and at a low cost in a manufacturing process with a small number of infrared transmitting lenses having different curvature radii of opposing optical mirror surfaces. To do.

[0005]

In order to achieve the above object, the present invention provides a first molding die having an optical mirror surface and a second molding die having a radius of curvature different from that of the optical mirror surface. A chalcogenide glass piece is placed in a space surrounded by a barrel mold that determines the thickness of a lens, and pressure is applied while maintaining the temperatures of the optical mirror surfaces of the first and second molding dies at different temperatures.

[0006]

According to this method, chalcogenide glass having a sharp temperature dependence of viscosity can be molded with good transferability.

[0007]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 has a surface roughness of 0.01 μ.
It is a first molding die having an optical mirror surface 2 of m or less. The optical mirror surface 2 is a convex surface having a radius of curvature of 5 mm and a diameter of 7 mm. 3 is a heater for heating the molding die 1, and 4 is a thermocouple for measuring the temperature of the optical mirror surface 2. 5 is the first
It is a press cylinder for pressurizing the molding die 1.
A second molding die 6 has an optical mirror surface 7 having a surface roughness of 0.01 μm or less. The optical mirror surface 7 has a radius of curvature of 100.
The concave surface has a diameter of 7 mm and a diameter of 7 mm. Reference numeral 8 is a heater for heating the second molding die 6, and 9 is a thermocouple for measuring the temperature of the optical mirror surface 7. Reference numeral 10 is a press cylinder for pressing the second molding die 6. 11 has a diameter of 6.
It is a disk-shaped glass piece made of chalcogenide glass having a thickness of 8 mm and a thickness of 2.6 mm. The glass piece 11 contains germanium (Ge) at 20 atomic% and selenium (Se) at 8%.
It is made of 0 atom% chalcogenide glass, and its softening point (temperature at which viscosity becomes 4.5 x 10 ⁷ poise) is 240 ° C.
Is. Reference numeral 12 is a barrel type that determines the thickness of the lens. With the above configuration, the optical mirror surface 2 is 270 ° C. and the optical mirror surface 7 is 250 ° C.
When the pressure is kept at 100 kg / cm ² for 3 minutes, the diameter is 7 mm and the opposing radius of curvature is 5 mm and 100 m.
A meniscus chalcogenide glass lens having a thickness of 2.5 mm and a thickness of 2.5 mm could be molded. Then, the surface of the lens was free of bubbles and the surface roughness was 0.01 μm or less.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a sectional view of a molding apparatus used to carry out the molding method of this embodiment. In the figure, 14 is a glass gob having 40 at% arsenic (As), 60 at% Se, and a softening point of 265 ° C. The optical mirror surface 2 is 295 ° C. and the optical mirror surface 7 is 275 ° C.
When the pressure is kept at 100 kg / cm ² for 3 minutes, the diameter is 7 mm and the opposing radius of curvature is 5 mm and 100 m.
A meniscus chalcogenide glass lens having a thickness of 2.5 mm and a thickness of 2.5 mm could be molded. Then, the surface of the lens was free of bubbles and the surface roughness was 0.01 μm or less. Since the glass gob is used in the molding method of this embodiment, the number of steps for molding the glass piece is smaller than that of the first embodiment in which the disk-shaped glass piece 11 is used.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a sectional view of a molding apparatus used to carry out the molding method of this embodiment. In the figure, 14 is 10 at.% Of Ge, 30 at.% Of As, 60 at.% Of Se, and three glass pieces having a softening point of 300 ° C., and the optical mirror surface 2 is 400 ° C. and the optical mirror surface 7 is 7.
Is maintained at 375 ° C., the space surrounded by the first and second molding dies and the barrel die is stored in the vacuum container 15, and the vacuum pump 16
100 kg / cm ² while evacuating and maintaining vacuum
When pressure was applied for 10 minutes, a meniscus-shaped chalcogenide glass lens having a diameter of 7 mm, opposing curvature radii of 5 mm and 100 mm, and a thickness of 2.5 mm could be formed. Then, the surface of the lens was free of bubbles and the surface roughness was 0.01 μm or less. In the molding method of this embodiment, since a plurality of glass pieces are weighed and used in a predetermined weight, there is no need for pre-processing, and the number of molding steps of glass pieces is smaller than that of the second embodiment.

The heating temperature in the present invention is preferably 10 to 100 ° C. higher than the softening point of the chalcogenide glass piece. The reason is that if the temperature is lower than 10 ° C., the pressurizing time becomes long and the transferability deteriorates, and if the temperature exceeds 100 ° C., it adheres to the mold or glass penetrates into the gap, which is not desirable.

As the chalcogenide glass of the present invention, Ge is 30 atomic% and Se is 7 in addition to the one explained in the embodiment.
The same effect was obtained even when the softening point was 0 atom% and the softening point was 390 ° C., Ge was 30 atom%, sulfur was 60 atom%, iodine was 10 atom% and the softening point was 400 ° C.

Further, although the spherical lens has been described in the embodiment, the same effect can be obtained by molding an aspherical lens.

[0014]

As is apparent from the above description, according to the present invention, it is possible to manufacture with a high precision, a high yield and a low cost in a molding process in which a small number of infrared transmitting lenses having different curvature radii of opposing optical mirror surfaces are used.

[Brief description of drawings]

FIG. 1 is a sectional view of a molding apparatus used to carry out a molding method according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a molding apparatus used for carrying out the molding method of the second embodiment.

FIG. 3 is a sectional view of a molding apparatus used to carry out the molding method of the third embodiment.

FIG. 4 is a cross-sectional view of a molding apparatus used to carry out a molding method in a conventional example.

[Explanation of symbols]

 1 1st shaping | molding die 2,7 Optical mirror surface 6 2nd shaping | molding die 11,13,14 Chalcogenide glass piece 12 Body type

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiko Yoshida 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A method comprising: a first molding die having an optical mirror surface; a second molding die having an optical mirror surface having a radius of curvature different from that of the optical mirror surface; and a body mold for determining a lens thickness. Put chalcogenide glass pieces in the open space,
A method for forming a chalcogenide glass lens, which comprises applying pressure while keeping the optical mirror surface of the forming die at different temperatures. 2. Surrounded by a first molding die having an optical mirror surface, a second molding die having an optical mirror surface having a radius of curvature different from that of the optical mirror surface, and a barrel mold for determining the thickness of a lens. A method for forming a chalcogenide glass lens in which a plurality of chalcogenide glass pieces are put in a space, the space is kept in a vacuum state, and pressure is applied while the optical mirror surfaces of the first and second molding dies are kept at different temperatures. . 3. From the softening point of chalcogenide glass pieces, 10
The method for molding a chalcogenide glass lens according to claim 1 or 2, wherein the pressure is applied while being maintained at a temperature higher by -100 ° C. 4. The method for molding a chalcogenide glass lens according to claim 1, wherein the pressure is applied while the temperature of the optical mirror surface having a small radius of curvature is kept higher than the temperature of the optical mirror surface having a large radius of curvature.