JPH0480858B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a novel apparatus for hot-pressing molding of optical elements.

Conventional techniques and their problems Conventionally, in order to manufacture glass optical elements, molten or softened glass is placed in a mold and pressure molded, or a glass material is placed in a mold and then heated together with the mold. , pressure molding is performed at a predetermined temperature. When molten or softened glass is pressure-molded, it is difficult to obtain optical elements with high precision due to "sink marks." Furthermore, although it is possible to obtain a highly accurate optical element by heating the glass material together with the mold, it takes time and has problems in terms of cost.

Means for Solving the Problems An object of the present invention is to provide a novel apparatus that can continuously heat and press mold high-precision optical elements without "sink marks."

According to the invention, the above object is to provide a hermetic heating housing, upper and lower mold means disposed within this insulating housing and cooperating to form a desired mold cavity, and means for relatively driving the means; a material supply means disposed within the housing for feeding a material between the upper and lower mold means when they are separated from each other; and a material supply means disposed within the housing. and means for heating the material before it is placed between upper and lower mold means; and means for receiving the molded article, located within the housing. This is accomplished by providing a device.

In a preferred embodiment of the invention, the material supply means comprises a hopper containing a plurality of materials, and a heat-resistant feed screw means extending between the outlet of the hopper and the region between the upper and lower mold means. It is designed to contain and supply materials at regular intervals.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

Referring to FIG. 1, the optical element molding apparatus shown here includes a heat insulating housing 1 which can be sealed by a door 2. The housing 1 is mounted on a movable base 4 having casters 3. In addition, door 2
It is preferable that a heater (not shown) is provided.

Inside the housing 1, there is a fixed frame 5,
A holder 6 is installed on this frame 5.
The holder 6 has a vertical hole 7 and a lateral hole 8 intersecting the hole 7 at right angles. The vertical hole 7 is divided into an upper hole portion 9 and a lower hole portion 10 with a horizontal hole 8 as a boundary. A rod-shaped upper mold member 11 protrudes into the upper hole portion 9, and the lower end of this upper mold member has a molding surface capable of molding the functional surface of the optical element to be molded. The upper mold member 11 is adapted to be moved downward by an air cylinder 12 installed outside the housing. A rod-shaped lower mold member 13 similarly protrudes into the lower hole portion 10, and its lower end also has a molding surface for molding the functional surface of the optical element to be molded. The lower mold member 13 is provided with suitable means (not shown), for example,
It can be moved into the lower hole section 10 and set into position by means of an air cylinder.
Note that it is preferable that this holder 6 is also provided with a heater, as will become clear later.

A material supply means 16 is connected to the horizontal hole 8 of the holder 6, and this material supply means includes a feed screw 17 made of a heat-resistant metal such as molybdenum. This feed screw 17 is made to rotate once every fixed period of time by a drive device 19 installed outside the housing via a drive shaft 18. Feed screw 1
The end of 7 on the holder side is connected to an inclined surface 20 in the horizontal hole, and as will be explained later, the spherical glass material sent rolls down this inclined surface 20 and enters the lower hole portion 10 of the holder. It is designed to rest on the molding surface of the lower mold member 13 therein.

A discharge port 22 of a hopper 21 is connected to the opposite end of the feed screw 17, and this hopper 21 accommodates a plurality of spherical glass materials 23. Therefore, when the feed screw 17 is rotated by the drive device 19, the materials 23 are fed out one by one from the discharge port 22 of the hopper 21, and as the feed screw 17 rotates, they are directed toward the horizontal hole 8 of the holder 6. and transported.

As best seen in FIGS. 2 and 3, a pair of reflectors 24 are installed near the top of the feed screw 17, and the opposing inner edges of these reflectors 24 are separated from each other, and the glass It constitutes a moving route for the material 23. An infrared heater 25 is installed adjacent to the upper surface of each reflecting plate 24, so that the glass material 23 being fed can be heated.

The lower mold member 13 is a tray member 28 that receives the molded product.
The central hole 29 of the tray member 2 also passes through it.
8 includes an annular wall 30 standing upright from its periphery and a conical central portion 31. After the glass material is molded as will be explained later, the lower mold member 13 is lowered to form the tray member 28. When the molded product reaches the top of the conical portion 31, it is pushed by a pushing means (not shown) and the center portion 31 is pushed.
It rolls down the slope and enters a depression 32 provided at the base of the upright wall. A large number of these recesses 32 are provided in the circumferential direction of the tray member 28, and during the molding operation, the tray member 28 is rotated or indexed so that the recesses 32 receive the molded products that fall one after another. It's summery.

During the molding operation, a previously polished glass bulb is placed in the hopper 21, the door 2 is closed, and the heat insulating housing 1 is hermetically sealed. Next, a vacuum pump (not shown) installed in the base 4 is activated to draw air inside the housing 1, and the inside is, for example,
10 ^-2 Torr. While maintaining this degree of vacuum,
The infrared heater 25 and other heaters are energized to heat the glass bulb 23. Next, the feed screw 17 is rotated to start feeding the glass bulb 23. The feeding speed and heating temperature are set so that the glass bulb material 23 is heated to 520° C. when it approaches the entrance of the horizontal hole 8 of the holder 6.

The frontmost glass bulb 23 rolls down the inclined surface 20 and falls into the lower hole portion 10 of the holder 6, and the lower mold member 1
Once placed on the molding surface 3, the lower mold member 13 is fixed at the position shown. Next, the air cylinder 12 is operated to lower and press the upper mold member 11 toward the lower mold member 13. As a result, the glass bulb is press-molded. For example, the molding pressure is approximately 100Kg/
cm ² and molding time is about 1 minute. At this time, the wall surface of the lower hole portion 10 of the holder 6 acts as a trunk shape. Therefore, it is preferable to provide the holder 6 with a heater as described above.

After the molding is completed, the upper mold member 11 is raised, the lower mold member 13 is gradually lowered, and the tray member 28 is lowered.
When the molded product approaches the top of the central portion 31 of the tray member 28, a pushing means (not shown) pushes the molded product into the receiving recess 3 of the tray member 28.
Drop it to 2. In this way, the glass bulbs 23 in the hopper 21 are molded one after another, and when there are no more glass bulbs in the hopper 21, the heater 25 is turned off, the vacuum valve is closed, and when the inside of the housing 1 has cooled down, After introducing air into the interior through a suitable pipe means, the door 2 is opened and the molded product is taken out.

Using this molding equipment, from glass type SF14 to 4th grade
As shown in the figure, outer diameter 5 mm, center thickness 3.02 mm, first
A lens was molded with a concave aspheric surface, reference R=4.198, a convex second surface R=3.075, and a focal length f=5.51. This lens had the desired high precision optical performance.

Effects of the Invention As described above, the molding apparatus according to the present invention can continuously manufacture highly accurate optical elements.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a molding apparatus according to the invention. FIG. 2 is a fragmentary plan view showing an enlarged feed screw portion of the molding device shown in FIG. 1. Figure 3 is the second
It is a sectional view along the - line of a figure. FIG. 4 is a diagram showing an example of a molded lens. In the drawings, 1... heat insulation housing, 2...
Door, 3...Caster, 4...Base, 6...Holder, 7...Vertical hole, 8...Horizontal hole, 11...Upper mold member, 12...Air cylinder, 13...Lower mold member,
16...Material supply means, 17...Feed screw, 18
... Drive shaft, 19 ... Drive device, 21 ... Hopper, 24 ... Reflection plate, 23 ... Heater.

Claims (1)

[Claims] 1. A sealable heat insulating housing, upper and lower mold means disposed within the heat insulating housing and cooperating to form a desired mold cavity, and a structure in which the upper and lower mold means are relative to each other. means for driving the material into the upper and lower mold means when the upper and lower mold means are separated from each other; An apparatus for manufacturing an optical element, comprising means for heating the molded article before it is placed between upper and lower mold means, and means disposed within the housing for receiving the molded article. 2. The optical element manufacturing apparatus according to claim 1, wherein the material supply means extends between a hopper containing a plurality of materials, a discharge port of the hopper, and a region between the upper and lower mold means. 1. An optical element manufacturing apparatus comprising a heat-resistant feed screw means for supplying materials at regular intervals.