JPS63295448A - Method for molding glass lens - Google Patents

Abstract

PURPOSE:To mold a glass lens contg. no bubbles intruded into the surface by pressing the side of a glass preform under heating and holding and by very precisely pressing the resulting raised surfaces. CONSTITUTION:A flat plate-shaped glass preform 3 is held between pressing barrel dies 4, 5 and subjected to primary pressing from the side. The deformed preform 3 is heated with a pair of molding dies 1, 2 each provided with a built-in heater and the resulting raised surfaces 6 are subjected to secondary pressing to obtain a lens. After they are allowed to stand until the lens is cooled to a temp. at which the lens can be released from the dies without deforming, the lens is released from the dies. Thus, the generation of bubbles on the surface of the lens during press molding is prevented and a desired optical lens including a convex lens can freely be press-molded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of forming a glass lens by precision molding for use in optical equipment.

BACKGROUND OF THE INVENTION In recent years, as a method for manufacturing high-precision optical lenses, especially aspherical glass lenses, methods have been implemented in which the lenses are formed only by press molding without using optical polishing. One of the shaping methods is to heat the glass body to a temperature at which it can be deformed, for example, close to its softening point, and then shape it using means such as a pressure press (for example, Japanese Patent Publication No. 51-60208). This method uses moldable glass materials that are easy to process,
For example, it is possible to cut pre-molten glass to form a flat plate, then polish this flat plate to a parallel mirror surface and then press mold it, making it possible to freely create complex shapes and reducing processing costs. Another advantage is that the appearance quality can be maintained at a high level.

An example of the above-mentioned press molding method will be described below with reference to FIG. FIG. 3 shows a sectional view during molding showing a conventional molding method, which has a pair of molding molds 11 and 12, between which a flat glass body 13 is placed in a circular mold 14. After heating to near the softening point by a press cylinder 16 with a built-in heater 15, the press cylinder 17 descends to perform press molding.

Problems to be Solved by the Invention However, with such a molding method, lenses of only some shapes can be molded, and in the case of convex lenses, air 18 is generated between the molding die 12 and the flat glass body 13 during press molding. becomes trapped, causing defects such as bubbles on the surface of the molded lens. On the other hand, many attempts have been made to solve this problem by making the glass body spherical or by pre-processing it into a shape that approximates the desired lens. However, such methods require high material processing costs and advanced processing techniques. Advantages of Pressure Molding The present invention aims to solve the above problems by producing a flat glass element with a relatively simple structure. The present invention provides a method that enables convex lens molding by a body. Specifically, by applying pressure while heating and holding the side surface of the glass body, and pressing the resulting raised curved surface with ultra-precision, it is possible to mold a glass lens without trapping air bubbles on the surface of the molded lens. This is what makes it possible.

Effect of the present invention By using the above-mentioned means, the side surface of a flat glass body is heated and pressurized, and a raised curved surface that approximates the shape of the obtained lens is press-molded, with a relatively simple structure, and the lens surface after pressing is It has the characteristics of maintaining high quality and making full use of the advantages of a flat glass element that can be processed at low cost.

EXAMPLE Hereinafter, an example of the method for molding a glass lens of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of a glass lens molding apparatus in an embodiment of the present invention. A pre-processed flat glass body 3 is held between pressing molds 4 and 5 by a preheated glass material conveying chute (not shown), and at the same time a primary pressing is performed from the side. After the deformation is completed, the mold is heated by a pair of molding molds with a built-in heater consisting of 1 and 2, a second press is performed on the raised curved surface 6, and the mold is maintained and cooled to a temperature at which the press can be opened, and then opened. was used.

FIG. 2(a) is a perspective view showing an outline of the press lubrication system according to the embodiment of the present invention, and has a structure in which the glass is held by the positioning part 7.

2nd issue) is a perspective view showing a glass body used in an example of the present invention, in which mirror polishing was performed only on the raised curved surface forming portion 6 that becomes the lens surface, and the heating and pressing surface 8. 9 was dealt with by rough grinding.

By the above-described molding method, it has become possible to press-mold a white lens using an inexpensive flat glass body.

Effects of the Invention As described above, the present invention heats and presses the side surface of a flat glass element and simultaneously presses a raised curved surface that approximates the obtained lens, so that the surface of the lens is formed during pressure molding. No more air bubbles, including convex lenses,
It has become possible to freely press mold any desired optical lens.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an outline of glass lens molding in an embodiment of the present invention, FIG. , Fig. 3 is a sectional view during molding showing conventional molding. 1.2... Pair of molds, 3, 13...
・Flat glass element, 4, 15...Heater,
5... Mold brace, 6... Raised curved surface,
7...Positioning part, 8.9...Heating and pressing surface, 11.12...Pair of molds, 14...
...Mold, 16.17...Press cylinder, 18...Trapped air. Name of agent: Patent attorney Toshio Nakao Haka1/, 2--
m - The mold in the sentence. 3-Ya! 1 shaku square ゛ rasuru 4 --- Higu 5 - 11 circle type, bracelet figure 2 5 - Rikan type bracelet 7 - Guwosui Joshoshi (α)

Claims (1)

[Claims] In this method, an optical element is obtained by holding a glass element in a pair of molds and press-molding it.The sides of the glass element are heated and pressurized to obtain a raised curved surface similar to the desired lens, and then pressed. A method of molding a glass lens, which is characterized by molding.