JP2003159718A - Method for manufacturing compound aspheric lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a ratio of non-defectives by hindering intrusion of bubbles. <P>SOLUTION: A concave lens 1 is horizontally set. Ultraviolet curing type resin liquid 10 is dropped onto its concave face 1A. A mold 2 having a convex aspheric face 2A is set with the aspheric face upside, and such quantity of resin liquid 10 as not to drip off when the mold is turned upside down is dropped onto a center of the aspheric face 2A. The mold 2 is turned upside down and placed above the lens 1. The lens 1 and the mold 2 are made to approach each other until a tip of resin liquid 10 on the concave face of the lens 1 is brought into contact with a tip of the resin liquid 10 on the aspheric face 2A of the mold 2. A space between the lens 1 and the mold 2 is further narrowed so as to have a predetermined space, and they are irradiated by ultraviolet light 20, while sandwiching the resin liquid 10 to be cured. A resin molded layer 10A obtained by curing is made to exfoliate from an interface with the mold 2. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a composite aspherical lens.

[0002]

2. Description of the Related Art As lenses used in optical products such as cameras and microscopes, glass lenses are mainly used. In the glass lens, a glass block (called a lens blank) press-molded from glass in a molten state is machined to produce a lens having a desired curvature. A method of manufacturing a resin lens by a method such as press molding, injection molding, or casting using a resin instead of glass has been put into practical use. In this method, once a mold is made, a large number of lenses can be mass-produced using it,
It is characterized by low manufacturing costs. However, the resin lens has a fatal defect that its optical performance greatly changes due to temperature change, and is not used for a highly accurate lens.

By the way, there is an aspherical lens as the lens, which is a lens whose surface shape is aspherical. this is,
It is important because it has excellent performance that cannot be obtained with spherical lenses. At present, as a method of manufacturing an aspherical lens from glass, there are mainly a method of grinding a blank and a method of manufacturing by a direct press. However, the grinding process has a drawback that mass productivity is low, and the direct press method has a limitation in the type and size of the glass type, which makes the equipment expensive.

In order to solve this drawback, a so-called compound aspherical lens has been developed. This is composed of a thin (for example, 5 to 100 μm) resin molding layer having an aspherical surface and a glass lens as a main component. The main glass lens has a spherical surface or a rough aspherical surface. Both are available at low manufacturing costs. Such a resin-bonded aspherical lens, that is, a compound aspherical lens, is manufactured by the following manufacturing method, for example. That is, a mold having a desired aspherical surface is placed horizontally, a predetermined amount of ultraviolet curable resin liquid is dropped in the center of the mold, and a glass lens having a spherical surface or an aspherical surface is placed on the mold to obtain a glass lens. The mold and the mold are brought close to each other by a certain distance, the resin liquid is irradiated with ultraviolet rays to be cured, and the cured resin is bonded to the glass lens to obtain a composite aspherical lens.

According to the above-described method of manufacturing a compound aspherical lens, sometimes bubbles (air bubbles) enter the resin molding layer. When the resin liquid and the mold come into contact with each other, the bubbles come in contact with each other from the outer peripheral portion, and the air remaining inside the contacted outer peripheral portion loses its escape and exists as an air pool. Since the product containing bubbles becomes a defective product, the conventional manufacturing method has a problem that the yield rate is low. Then, as a thing which improved the non-defective rate by making it difficult for bubbles to enter, the patent No. 319
The one described in Japanese Patent No. 1447 was developed.

The manufacturing method (conventional patent invention) described in Japanese Patent No. 3191447 includes a first step: a step of horizontally placing a glass lens having a spherical surface or a rough aspherical surface; a second step: a central portion of the glass lens. A step of dropping a predetermined amount of radiation (ultraviolet) curable resin liquid on the above; 3rd step: a step of inverting the top and bottom of the glass lens; 4th step: placing the glass lens on a "mold having a desired aspheric surface" Step of placing: Fifth step: Step of bringing the distance between the glass lens and the mold close to a predetermined value; Sixth step: Radiation (ultraviolet ray) to the resin liquid sandwiched between the glass lens and the mold ) Is applied to cure the resin molding layer; and the seventh step: a step of peeling the resin molding layer obtained by curing from the interface with the mold.

[0007]

In the conventional patented invention,
In the second step, when "the resin liquid is dripped on the central portion of the glass lens", if the amount of the resin liquid is sufficient to finally obtain the resin molding layer, if the viscosity of the resin liquid is not so high, the glass lens There is a risk that it may flow down from the central portion, or it may drip during the next reversal of the third step. In addition, the smaller the radius of curvature of the convex surface of the central portion of the glass lens, the more the glass lens flows down. For example, when forming a resin molding layer having a center thickness of 150 μm and an outer diameter of 51 mm, a resin liquid having a viscosity of 1000 cps (the amount required for forming a resin molding layer is 0.522 g) is applied to the center of a concave lens having a radius of curvature R37 (mm). When 0.123 g was dripped and the concave lens was turned upside down, the resin liquid dripped down. Further, when forming a resin molding layer having a center thickness of 200 μm and an outer diameter of 57 mm, a resin liquid having a viscosity of 1000 cps (the amount necessary for forming the molding layer is 0.
355 g) dropped 0.095 g, and when it was turned upside down, it fell down.

Therefore, the present invention aims to improve the yield rate by making it difficult for bubbles to enter by a method different from the conventional patented invention.

[0009]

In order to achieve the above object, according to the present invention, a concave lens which is a base material of an aspherical lens is horizontally set and an ultraviolet curable resin liquid is dripped on the concave surface. , With the desired convex aspherical surface, turn the surface of this mold upside down by dropping an amount of UV curable resin liquid on the central part of the aspherical surface with the aspherical surface facing upward and not dripping when reversing. Then, it is placed on the lens, and the two are brought close to each other until the resin liquid on the concave surface of the lens is brought into contact with the tip of the resin liquid on the aspherical surface of the mold, and the distance between the lens and the mold is narrowed to a predetermined distance. And put the resin liquid between them,
The resin liquid between the lens and the mold is cured by irradiating it with ultraviolet rays, and the resin molding layer obtained by curing is separated from the interface with the mold. In addition, a mold having a desired concave aspherical surface is set horizontally, and an ultraviolet curable resin liquid is dropped on the aspherical surface, and the convex lens serving as the base material of the aspherical lens is placed with its convex surface facing upward. Then, drop an amount of the UV curable resin liquid on the center of the convex mold surface so that it does not drip when inverted, place it on the mold by reversing the top and bottom of this lens, and apply it to the aspherical resin liquid of the mold. Bring the two together until the tip of the resin liquid on the convex surface of the lens comes into contact with each other, and further close the gap between the lens and the mold until a predetermined distance is reached, sandwich the resin liquid between the two, and then the lens and the mold. The resin liquid between the two is cured by irradiation with ultraviolet rays, and the resin molding layer obtained by curing is separated from the interface with the mold.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a concave glass lens 1 as a base material of an aspherical lens is set horizontally and its concave surface 1A is set.
FIG. 3 is a cross-sectional view showing a state in which the ultraviolet curable resin liquid 10 has been dropped onto the glass and a predetermined time has elapsed. The resin liquid 10 on the concave surface 1A
Becomes a flat surface after a predetermined time has elapsed.

Next, the die 2 having the desired convex aspherical surface 2A is turned upside down, and the ultraviolet curable resin solution 10 is turned upside down by an amount that does not drip when inverted. It shows a state of being dropped on the central portion of the (see FIG. 2). Since the resin liquid 10 has an appropriate viscosity, it does not drip from the convex aspherical surface 2A as long as the amount is not more than a certain amount. In this state, the mold 2 is turned upside down and placed on the lens 1, and the resin liquid 10 on the concave mold surface 1A of the lens 1 is brought close to the tip of the resin liquid 10 on the aspherical surface 2A of the mold 2. (See Figure 3).

From the state shown in FIG. 3, the distance between the lens 1 and the mold 2 is further narrowed and brought close to each other until the predetermined distance is reached, and the resin liquid 10 is sandwiched between the two, and in the state shown in FIG.
The resin molding layer 10A obtained by curing the resin liquid 10 between the mold 2 and the mold 2 by irradiating it with ultraviolet rays 20 and curing the resin liquid.
By peeling from the interface with the mold 2, a composite aspherical lens is manufactured.

The ultraviolet curable resin liquid 10 used here is
Viscosity of 1000-1300 cps and viscosity of 1000-
The one having 2500 cps is preferably used.

In another embodiment shown in FIGS. 5 to 8, a mold 21 having a desired concave aspherical surface 21A is set horizontally, and the ultraviolet curable resin liquid 10 is dropped on the aspherical surface 21A to obtain a predetermined shape. It shows a state in which the surface of the resin liquid 10 becomes close to a flat surface after a lapse of time (see FIG. 5). Then, the convex lens 11 made of glass, which is the base material of the aspherical lens, is attached to the convex surface 1
With 1A facing upward, an amount of the UV curable resin liquid 10 that does not drip when inverted is dropped on the central portion of the convex surface 11A (see FIG. 6).

The lens 11 in the state shown in FIG. 6 is turned upside down and placed on the mold 21. The resin liquid 10 on the aspherical surface 21A of the mold 21 is brought close to the tip of the resin liquid 10 on the convex mold surface 11A of the lens 11 (see FIG. 7).

Further, the distance between the lens 11 and the mold 21 is narrowed and brought close to each other until the predetermined distance is reached, and the resin liquid 10 is sandwiched between the two, and the resin liquid 10 between the lens 11 and the mold 21 is sandwiched.
The composite aspherical lens can be manufactured by irradiating the resin with ultraviolet rays 20 to cure the resin (see FIG. 8), and peeling the cured resin molding layer 10A from the interface with the mold 21.

The resin liquid 10 to be dropped on the side to be reversed may have a small amount of 1 to 2 mm in diameter. The minute amount of the resin liquid 10 does not droop when inverted, and when the lens 11 and the mold 21 are brought close to each other by a predetermined distance, the contact surface between the resin liquid 10 and the resin liquid 10 is narrow, so to speak. The contact area may be gradually expanded from the contact state. In the related art, the contact surface between the mold 21 and the resin liquid 10 or the lens 11 and the resin liquid 10 is wide, so to speak, it is a surface contact, and there is a risk that air bubbles may be mixed.

In order to enhance the adhesive force between the lenses 1 and 11 and the resin molding layer 10A, it is desirable to subject the surfaces of the lenses 1 and 11 to silane coupling treatment in advance. The silane coupling agent can be used by diluting it with a 2 wt% ethanol solution.

[0020]

As described above, according to the present invention, the amount of resin liquid that does not droop when inverted is applied to the convex lens side or the mold side having the convex aspherical surface. , The central portion of the convex surface, the resin liquid is dropped on the concave surface of the other concave mold or lens, and the lens liquid or Invert the convex surface of the mold so that it faces downward, contact the resin liquid in the center with other resin liquids in a narrow range, so to speak, point contact, and gradually widen the contact surface of the resin liquid, It is possible to prevent bubbles from being mixed into the resin molding layer. In addition, the non-defective rate is also improved. In particular, the present invention is useful for a lens having a large amount of aspherical surface and a lens having a thick center thickness of the resin molding layer.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state where an ultraviolet curable resin liquid is dropped on the concave surface of a concave lens.

FIG. 2 is a cross-sectional view of a state where a drop of an ultraviolet curable resin liquid is dropped on the convex surface of a convex mold.

FIG. 3 is a cross-sectional view of a state in which the mold is turned upside down from the state of FIG.

FIG. 4 is a cross-sectional view of a state in which a resin molding layer is formed by irradiating ultraviolet rays.

FIG. 5 is a cross-sectional view showing a state in which a resin liquid is dropped on the concave surface of a mold showing another embodiment.

FIG. 6 is a cross-sectional view of a state in which one drop of resin liquid is dropped on the convex surface of the convex lens.

7 is a cross-sectional view of a state in which the lens is turned upside down and brought close to a mold in the state of FIG.

FIG. 8 is a cross-sectional view of a state where a resin liquid is sandwiched between a lens and a mold and ultraviolet rays are irradiated to form a resin molding layer.

[Explanation of symbols]

1,11 lens 1A concave surface 11A convex surface 2,21 mold 2A, 21A aspherical surface 10 UV curable resin liquid 10A resin molding layer 20 UV

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Claims (4)

[Claims] 1. A concave lens which is a base material of an aspherical lens is set horizontally, and an ultraviolet curable resin liquid is dropped on the concave surface to form a mold having a desired convex aspherical surface. With the UV curable resin liquid on top of the lens, drop an amount of UV curable resin liquid onto the center of the aspherical surface so that it does not drip when inverted, place it on the lens by inverting the top and bottom of the mold, Bring the aspherical surface of the resin liquid closer to each other until they come into contact with each other, and further close the gap between the lens and the mold until a predetermined distance is reached, and then sandwich the resin liquid between the two. A method for producing a composite aspherical lens, characterized in that the resin liquid between the resin and the resin is cured by irradiating it with ultraviolet rays, and the resin molding layer obtained by curing is separated from the interface with the mold. 2. A mold having a desired concave aspherical surface is set horizontally, and an ultraviolet curable resin liquid is dropped on the aspherical surface to form a convex lens as a base material of the aspherical lens. The UV-curable resin liquid is dropped onto the center of the convex mold surface with the surface facing upward so that it does not drip when inverted, and the lens is turned upside down and placed on the mold. Bring the resin liquid closer to the tip of the resin liquid on the convex surface of the lens, and close the gap between the lens and the mold until a predetermined gap is reached, and sandwich the resin liquid between the two. A method for producing a composite aspherical lens, characterized in that the resin liquid between the mold and the mold is cured by irradiating it with ultraviolet rays, and the resin molding layer obtained by curing is separated from the interface with the mold. 3. The viscosity of the ultraviolet curable resin liquid is 100.
It is 0-2500 cps, The manufacturing method of the compound aspherical lens of Claim 1 or 2 characterized by the above-mentioned. 4. A drop of the ultraviolet curable resin liquid to be dropped on the upside-down side is about 1 to 2 mm, and one drop is dropped. Manufacturing method of compound aspherical lens.