JP2005089217A - Method of manufacturing lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the restriction to the design of a short focus lens and to improve the reliability of the air tightness of the boundary between a lens and a lens holder. <P>SOLUTION: The design of the lens from a short focus lens to a long focus lens is freely performed by providing a sealing wall extending in the vertical direction from a light transmitting window outer peripheral end of a shell and setting up the length of the sealing wall and the curvature of a lens optical surface in press molding. The highly reliable air tightness is attained by heating a glass column of a lens base material to a temperature equal to or above a glass softening point as primary molding before the press molding (secondary molding) to melt-stick the glass to the inner peripheral surface of the sealing wall of the shell. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a lens.

  As a conventional manufacturing method, there is a method in which a glass sphere is fixed to the inner surface of a lens holder, and the holder and the lens are integrally molded by a pressing method in which the lens sphere is heated and pressed with the lens holder as a reference (for example, , See Patent Document 1).

  3 and 4 show a conventional manufacturing method described in Patent Document 1, in which 110 is a lower mold and 120 is an upper mold in the manufacturing method shown in FIG. An insert 130 is slidably provided in the lower mold 110, and an insert 140 is slidably provided in the upper mold 120. The top surface of the insert 130 and the bottom surface of the insert 140 are concave or aspherical optical transfer surfaces 130a and 140a. Reference numeral 150 denotes a lens holder. FIG. 4 is a cross-sectional view showing the optical component after molding.

Next, as a method for manufacturing an optical component, the lens holder 150 is positioned and fitted in the upper surface recess 110 a of the lower mold 110. The spherical glass material 160 is placed in contact with the inner peripheral surface 150a of the lens holder 150. At this time, the projection 150b protruding from the inner peripheral surface of the lens holder 150 prevents the lens material 160 from falling off. In addition, the lens holder 150 has a function for holding the pressed lens in the lens holder 150. In FIG. 3, a heating member (not shown) is opposed to the outer periphery of the lens holder 150. The lens holder 150 is heated by this heating member (not shown), and the lens material 160 is further heated. Then, the inserts 130 and 140 are driven in the clamping direction, and the spherical lens material 160 is pressure-molded by the optical transfer surfaces 130a and 140a. As shown in FIG. 4, a spherical or aspherical optical surface is obtained. A lens 160a having 160b and 160c is press-molded. In the pressing process, the lens material 160 is manufactured by pressure bonding to the inner surface of the lens holder 150.
Japanese Patent Laid-Open No. 03-237023

  However, in the conventional manufacturing method, considering that the spherical lens material 160 placed in the inner peripheral surface 150a of the glass holder is molded with a press, the optical transfer surfaces 130a and 140a of the mold inserts 130 and 140 of the molding apparatus are used. This curvature must be a smaller value than the curvature of the spherical lens material 160.

  Further, the lens thickness becomes smaller than the diameter of the spherical lens material 160 by the press molding.

  That is, if the lens optical surfaces 160b and 160c having a large curvature are obtained in the conventional manufacturing method, the diameter of the spherical lens material 160 must be reduced, and if the lens thickness is increased, a spherical lens having a large diameter is obtained. The material 160 must be used, and a lens optical surface with a large curvature and a large lens thickness cannot be obtained at the same time.

  Therefore, it is difficult to manufacture a short focus lens that requires a large lens optical surface curvature and a large lens thickness in the glass lens 160a.

  In addition, when molding the spherical lens material 160 with the optical transfer surfaces 130a and 140a, it is a temperature suitable for molding, and it is molded at a relatively low temperature lower than the glass softening temperature so that the viscosity is not insufficient. Although the glass holder inner peripheral surface 150a and the glass lens 160a are mechanically in close contact with each other, since the molecular structure is not continuous, the reliability of airtightness between the glass holder inner surface and the glass interface is low. Furthermore, a thick cutting lens holder that can withstand the pressing pressure during glass molding is required, and the lens surface after molding is made into a mirror surface required for the lens optical surface for molding at low temperatures. For this reason, the spherical lens material 160 has a problem that a mirror finish is necessary in advance.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described conventional problems, and to provide a method for manufacturing a lens cap that is not air-tight and has high airtightness and is inexpensive.

  A primary molding process for fusing the metal frame and the lens material and forming both ends of the lens material in a mirror state; and a secondary molding process for forming a lens optical surface by clamping the mirror surface portions at both ends of the lens material with a mold. It is equipped with.

  According to this configuration, the lens has a high degree of freedom in designing the focal length, the airtightness between the lens and the metal frame body is high, and the lens can be manufactured at a low cost.

  As described above, according to the lens manufacturing method of the present invention, there is a high degree of freedom in designing the focal length from the short focal point to the long focal point, and the airtightness is highly airtight and highly reliable. I can do it.

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

  FIGS. 1A and 1B and FIGS. 2A and 2B are cross-sectional views along the manufacturing process flow of the optical semiconductor lens cap according to the embodiment of the present invention.

  In FIGS. 1A and 1B and FIGS. 2A and 2B, reference numeral 1 denotes an assembly jig made of carbon or ceramic, and 2 denotes a seat having an opening on the main surface of the assembly jig 1. Recessed hole, 3 is a conical concave portion at the bottom continuous from countersink hole 2, 4 is a shell formed by cutting a metal made of, for example, Fe-Ni-Co alloy (hereinafter referred to as Kovar) as a frame, 5 is a shell top wall, 5a is an outer surface of the top wall, 5b is an inner surface of the top wall, 6 is a sealing wall extending vertically from the outer peripheral edge of the light transmitting window at the top of the shell, and 6a is an outer periphery of the sealing wall. 6b is an inner peripheral surface of the sealing wall, 7 is a cylindrical wall extending vertically from the outer peripheral end of the shell top wall, 7a is an outer peripheral surface of the cylindrical wall, 7b is an inner peripheral surface of the cylindrical wall, and 8 is a shell cylinder A flange extending horizontally from the end of the wall, 8a is on the top surface of the flange, 8b is on the circumferential surface of the bottom surface of the flange The apex of the welding allowance, 9 is the cylindrical lens material, 10 is the inner peripheral surface of the shell sealing wall when the cylindrical lens material 9 heated above the glass softening point in the state of FIG. 6b and an intermediate processed product in which the upper and lower ends of the cylindrical lens material 9 are formed into a spherical shape by surface tension, 11 is a lower mold, 12 is an upper mold, 13 and 14 are nested, and 13a and 14a are optical transfer surfaces. , 15 are lenses, and 15a and 15b are lens optical surfaces.

  A detailed configuration will be described below.

  After the shell 4 is inserted into the assembly jig 1 and the main surface portion of the assembly jig 1 is inserted into the gap between the outer peripheral surface 6a of the shell sealing wall and the inner peripheral surface 7b of the shell cylindrical wall, the cylindrical lens material 9 is sealed with the shell. It inserts in the state inscribed in the wall internal peripheral surface 6b, and contact | abuts to the recessed part 3 of the assembly jig 1 (FIG. 1 (a)). The shell 4 at this time has been subjected to a process for forming a metal oxide film on the surface in advance by a conventional method using an oxidation furnace or the like.

  The assembly jig 1 is heated at 850 ° C. for 10 minutes in a nitrogen atmosphere (FIG. 1B). As a result, the cylindrical lens material 9 is made of, for example, borosilicate glass, and since the softening point is 700 ° C., the cylindrical lens material 9 is heated to the softening point or higher, and the cylindrical lens material 9 and the inner peripheral surface 6b of the shell sealing wall are formed. Bonding via a metal oxide film (not shown) on the shell surface forms a hermetic seal that is continuous in molecular structure. At the same time, the upper and lower ends of the cylindrical lens material 9 are molded into a spherical surface using the wettability of the glass surface tension and the metal oxide film of the glass to form the intermediate workpiece 10. At this time, since nothing is in contact with the glass surface, it becomes a mirror surface. Thereby, the primary molding of the cylindrical lens material 9 is completed.

  The lens cap once cooled after the primary molding is taken out from the assembly jig 1 and the intermediate workpiece 10 of the cylindrical lens material 9 is subjected to secondary molding.

  The lens cap is fitted to the lower die so as to contact the welding top apex 8b existing on the shell top inner surface 5b, the shell cylindrical wall inner peripheral surface 7b, and the flange lower surface. Next, the upper mold is brought into contact with the outer surface 5a of the shell top wall, the outer peripheral surface 7a of the shell cylindrical wall, and the upper surface 8a of the shell flange, and the mold is clamped. A heating member (not shown) faces the outer periphery of the lens cap, the shell is heated by this heating member (not shown), and further heated to a temperature at which the intermediate workpiece can be molded, for example, 650 ° C. . Then, the inserts 13 and 14 are driven by the force of 80 N in the clamping direction so that the intermediate workpiece 10 is molded by the optical transfer surfaces 13a and 14a. On the other hand, it stops with a gap. As a result, the intermediate workpiece 10 that has been pressurized during molding is molded and escapes from the gap held between the inserts 13, 14 and the shell in the horizontal direction. 4 is prevented from being pressurized (FIG. 2A).

  Thus, the lens cap is formed with the lens 15 having the spherical or aspherical lens optical surfaces 15a and 15b (FIG. 2B).

  According to such a configuration, the distance L of the sealing wall 6 of the shell can be freely set, and the curvature design range of the optical transfer surfaces 13a and 14a of the nesting and the cylindrical diameter of the cylindrical lens material 9 associated therewith can be freely set. As a result, since the degree of freedom of the lens thickness and the curvature of the lens optical surface is high, it is possible to manufacture a lens from a short focal point to a long focal point.

  Further, by heating the cylindrical lens material 9 to 850 ° C. above the softening point of the glass during the primary molding shown in FIG. 1B, an intermediate workpiece 10 between the shell sealing wall inner peripheral surface 6b and the cylindrical lens material 9 is obtained. Between them, they are completely bonded via a metal oxide film (not shown) on the shell surface to form a hermetic seal having a continuous molecular structure.

  As a result, the device is highly airtight and highly reliable, and when used as a lens cap of an optical semiconductor device or the like, it is possible to keep the operation stability of the device high.

  Similarly, at the time of the primary molding, the upper and lower ends of the cylindrical lens material 9 are formed into a spherical shape by utilizing the surface tension of the glass to form the intermediate workpiece 10, but the surface is required for the lens optical surface. It is a specular surface. Therefore, it is not necessary to perform mirror finishing on the cylindrical lens material 9 in advance, as in the case of the spherical lens material 160 as used in the conventional manufacturing method.

  Further, the pressure applied during the secondary molding shown in FIG. 2A is directly applied to the shell 4 because the glass protrudes and escapes from the gap maintained between the shell 4 and the inserts 13 and 14. The pressure is not applied.

  As described above, in the present embodiment, the frame has been described using a shell obtained by cutting a metal made of Kovar. However, it is also possible to use a thin metal press shell in consideration of economy and mass productivity. .

  The material of the frame is not limited to Kovar, and other metals such as Fe-Ni alloy and SUS can be used.

  Furthermore, although glass was used as the lens material, a resin such as polycarbonate or polymethyl methacrylate may be used.

  It is useful as an airtight cap and lens in the field of optical components, and is particularly suitable for light receiving and emitting elements of optical semiconductors.

Sectional drawing along the manufacturing process in embodiment of this invention Sectional drawing along the manufacturing process in embodiment of this invention Sectional drawing of the shaping | molding method in conventional embodiment Complete sectional view in the conventional embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Assembly jig 2 Counterbore 3 Recess 4 Shell 5 Shell top wall 5a Shell top wall outer surface 5b Shell top wall inner surface 6 Sealing wall 6a Sealing wall outer peripheral surface 6b Sealing wall inner peripheral surface 7 Cylindrical wall 7a Cylindrical wall outer periphery Surface 7b Cylindrical wall inner peripheral surface 8 Flange 8a Flange upper surface 8b Flange apex 9 Cylindrical lens material 10 Intermediate workpiece 11 Lower mold 12 Upper mold 13 Nesting 14 Nesting 13a, 14a Optical transfer surface 15 Lens 15a, 15b Lens optical surface 110 Lower mold 110a Lower mold recess 120 Upper mold 130,140 Nest 130a, 140a Optical transfer surface 150 Lens holder 150a Lens holder inner peripheral surface 150b Lens holder protrusion 160 Spherical lens material 160a Glass lens 160b, 160c Lens optical surface

Claims (5)

A primary molding process for fusing the metal frame and the lens material and forming both ends of the lens material in a mirror state, and a secondary molding for forming a lens optical surface by pressing the mirror surface portions at both ends of the lens material with a mold. And a process for producing a lens. The method for manufacturing a lens according to claim 1, wherein the primary molding step is formed in a mirror state at a temperature equal to or higher than a softening point of the lens material. 3. The method for manufacturing a lens according to claim 1, wherein the primary molding step improves the wettability with the glass by oxidizing the surface of the metal frame in advance, thereby facilitating the glass molding. The lens manufacturing method according to claim 1, wherein the secondary molding step forms a lens optical surface at a temperature equal to or lower than a softening point of the lens material. 5. The method for manufacturing a lens according to claim 1, wherein in the secondary molding step, the mold for clamping is stopped while maintaining a certain gap with the metal frame.

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