JPS63252931A - Production of nonspherical surface lens - Google Patents

Abstract

PURPOSE:To simply obtain a nonspherical surface lens useful as searchlight, etc., by pouring molten glass into the rotary surface of molten lead while rotating the molten lead in a furnace together with the furnace in such a way that the melt surface of lead becomes a nonspherical surface shape and cooling. CONSTITUTION:Molten lead AG is fed to a furnace 1 consisting of a heating nichrome wire 2, a shaft 3 and a revolving mechanism 4 of NC control circuit to balance by a correlation equation shown by formula I [x is horizontal line; y is axis of ordinate; K is function of angular speed omega(rad/s) and specific gravity of molten lead r] up to desired depth. Then the furnace 1 is rotated at desired angular speed omega(rad/s), the lead surface is made into a nonspherical surface (parabola) of a curved line equation shown by formula II (g is acceleration of gravity; H is depth of molten lead) and made into a stationary state. Then molten glass S is poured from an electric furnace 6 through a conduit 5 to the rotary surface of the molten lead AG of nonspherical surface in the furnace 1 and annealed to solidify the molten lead AG and the molten glass S. Then the glass of nonspherical surface is taken out from the mold face of the molten lead AG and processed to give a nonspherical lens.

Description

[Detailed description of the invention] b) Industrial application field The present invention is a proposal regarding a method for manufacturing an aspherical lens.

More specifically, by rotating the molten lead liquid together with the furnace at a required angular velocity, an aspherical rotating surface is formed on the surface of the lead liquid, and the furnace is continuously rotated while keeping the rotating surface constant. The aim is to pour molten glass liquid into the glass to obtain an aspherical vitreous body that is identical to the aspherical surface of the lead liquid.

(1) Prior Art Conventionally, methods for obtaining an aspherical lens include (1) a pressing method, (2) a cutting method, and (3) a molding method.

The pressing method is a method in which thin glass is pressed onto the surface of an aspherical metal plate such as a searchlight, and the cutting method is a method in which the vitreous body is cut into an aspherical shape using a diamond. The method is to pour glass liquid into an aspherical mold and cool it to solidify it.

C) Problems to be Solved by the Invention In all of the prior art methods for manufacturing aspherical lenses as described above, processing of the aspherical surface itself is extremely difficult compared to that of general spherical lenses.

The method for manufacturing an aspherical lens of the present invention is completely different from the conventional method of determining an aspherical surface, and has succeeded in easily determining an aspherical lens.

When the method of the present invention is compared with that of the above-mentioned prior art, it can be said that it is similar to the mold method.

2) Means for Solving the Problems The present invention rotates the lead liquid melted in the furnace at a required angular velocity together with the furnace, thereby causing the furnace to rotate while keeping the aspherical rotating surface formed on the surface of the lead liquid constant. A method for producing an aspheric lens, which is characterized by continuing the process, pouring molten glass liquid onto an aspheric rotating surface, and cooling the furnace to obtain an aspheric vitreous body that is the same as a lead surface.

That is.

E) Function Since the present invention is constructed as described above, the aspherical surface is formed by a spherical rotating surface generated on the lead liquid surface by rotating the lead liquid melted in the furnace at the required angular velocity together with the furnace. It is something that will be done.

The furnace continues to rotate while keeping the shape of the rotating surface constant, and molten vitreous liquid is poured onto the aspherical rotating surface, and the vitreous liquid is transformed into an aspherical vitreous body having the same shape as the aspherical rotating surface. to form.

In other words, the specific gravity of lead is 11.23, and the specific gravity of glass (for optical use) is 2.37, so even if the vitreous solution is placed on top of the lead solution, they will not mix due to the difference in specific gravity, and each will have the same aspherical surface. By gradually cooling the furnace, an aspherical vitreous body can be obtained using a lead mold.

f) Example The furnace (1) used in the present invention is an electric furnace having a cylindrical shape with a bottom and a nichrome wire (2) for heating the furnace body wrapped around it, and a shaft in the center of the furnace. (3) is attached, and the shaft (3) is rotatably mounted by a required rotation mechanism (4).

Although not shown, an NC control circuit is incorporated in the rotation mechanism (4), and the angular velocity (ω) of the furnace body (1) is set relative to the horizontal line (x) and the axis (3) is the vertical axis (y). The structure is such that it can be rotated accurately and in a well-balanced manner.

That is, as shown in Figure 3, y=Kx''K is the angular velocity (
ω) (rad/s) and the specific gravity (r) of the molten metal.

Lead (AG) is housed in the furnace body (1), the lead (AG) is melted in the furnace body by applying electricity to the nichrome wire and heating the furnace body, and the lead liquid is transferred together with the furnace body through a rotating mechanism. (4)
It rotates at an angular velocity (ω) via the shaft (3).

Due to this rotation, a required aspheric surface of rotation is formed on the surface of the lead solution according to the value of (ω).

The furnace body continues to rotate while keeping the shape of the aspherical rotating surface constant, and this rotation is performed extremely quietly and is controlled by an NC circuit to prevent ripples on the liquid surface. It is something that

The aspherical rotating surface is used as a type of mold, and the molten glass liquid (S) from the electric furnace (6) is poured into the rotating surface through the conduit (5). ) and lead solution (AG) have different specific gravity, and since the specific gravity of lead is large, the glass solution has an aspherical state in which the entire glass method has the same shape as the rotation surface of the lead solution due to the rotation surface of the lead solution. When molded and gradually cooled while rotating the furnace body, the lead liquid solidifies with the aspheric rotating surface, and the glass liquid also solidifies in the same way. Either you can use it as is as an aspherical lens, or you can put an A on the back side of the vitreous.
It is coated with C plating and used as a reflecting mirror.

The most important point in implementing the above is to rotate the furnace body at the required angular velocity, form an aspherical rotating surface of the desired shape on the lead liquid surface, and continue rotating while keeping the shape constant.
This is a process in which the lead liquid is cooled from a liquid to a solid at the same time as the glass liquid is poured onto the aspherical rotating surface.

The above embodiment will be further explained by showing specific numerical values.

As shown in FIG. 4, a lead solution is poured to a depth Ho into a furnace having a diameter d.

As shown in Figure 5, the furnace is moved at an angular velocity ω (radian/second)
When rotated by , the curve equation on any vertical axis section of the resulting curved surface can be expressed as follows.

g Here, g: acceleration of gravity.

Therefore, the curve becomes a parabola (aspherical surface).

This is theoretically accurate and is not affected by the specific gravity, viscosity, or surface tension of the liquid.

However, a constant rotational speed must be maintained and the flow must be maintained in a steady state.

There should be no ripples, accelerations, decelerations or vibrations.

The area shown in Figure 5 deviates from the parabola due to the surface tension acting between the liquid and the furnace wall.Therefore, if the molten glass liquid is filled to this area, it will create an error as an aspherical lens, so only the area near the center is used. do.

If the number of revolutions per minute is n = 95, ω=9.9484 (rad/s) 4 X 980 Ho is a constant and is unrelated to the parabolic shape.

Aspherical lenses and spherical lenses (radius 10
A comparison between 0ran and 1501111) is shown in Figure 6.

Of course, by arbitrarily adjusting or changing the rotational speed of the furnace, an aspheric lens or reflecting mirror made of any parabolic rotating surface can be made.

g) Effects of the Invention Since the present invention is constructed as described above, it is possible to create a desired aspherical surface on the lead plate surface melted in the furnace body by adjusting the numerical value of the angular velocity of rotating the furnace, which is considered to be the most difficult task in the past. Since it is possible to mold a rotating surface of the shape, by controlling and rotating the furnace body while holding the rotating surface constant, an optical glass solution having a specific gravity lower than that of the rust solution is poured in, thereby removing the rust solution. Since the spherical rotating surface serves as a type of mold and it is possible to easily obtain the required aspherical vitreous body, this is a useful invention that has revolutionized the conventional manufacturing method of aspherical lenses.

[Brief explanation of drawings]

The attached drawings are explanatory diagrams showing an embodiment of the method of the present invention, and FIG. 1 is a side view of the entire apparatus, FIG. Figure 3 is an explanatory diagram of the direction in which angular velocity (ω) is applied to the furnace body, Figure 4 is a side view of the state in which lead is poured into the furnace body, and Figure 5 is an aspherical rotating surface formed in the rust liquid inside the furnace body. FIG. 6 is a graph showing a comparison of the spherical surfaces of a general spherical lens and an aspherical lens of the present invention. In addition, the symbol in the figure

Claims (1)

[Claims] The molten lead liquid is rotated together with the furnace at the required angular velocity, and the furnace continues to rotate while keeping the aspherical surface of rotation generated on the surface of the lead liquid constant. A manufacturing method for aspherical lenses characterized by pouring a liquid and cooling a furnace to obtain an aspherical vitreous body that is the same as a lead surface.