JPS62260103A - Lens and its preparation - Google Patents

Abstract

PURPOSE:To produce a special optical lens having a stable optical capacity and a durability by providing a glass body part and an optical refracting face which is formed on the outside of this body part by press forming. CONSTITUTION:A glass lens 1 having spherical surfaces is produced with glass, and CO2 laser light 3 from a CO2 laser device is projected to one surface 2 of this lens 1 supported on a supporting base 11 through a mirror 10 to form a softened surface layer part 4. The other surface 5 of the lens 1 is held on a bottom force 6 and a top force 7 is allowed to fall in the direction of an arrow R to form the softened surface layer part 4 to an aspherical surface by press work. Thereafter, the lens 1 is cooled and the top force 7 is separated from the bottom force 6 to take out the lens 1. A spherical lens approximating a nonspherical lens to be produced is produced as the lens 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an aspherical or Fresnel type lens made of glass and a method for manufacturing the same.

(Prior art) In the past, aspherical or Fresnel lenses were mainly produced by injection molding of PMMA (?cryl resin), ■pressing of glass,
This is accomplished using three methods: coating a 0-spherical glass lens with an acrylic resin coating using a photopolymer method to form an IJI-Lfi lens.

However, in the method (2) above, since the refractive index of the plastic lens is smaller than that of glass, the radius of curvature of the plastic lens must be made small, which has the drawback of increasing the bonding and wall thickness. Furthermore, since the change in refractive index of plastic lenses is highly dependent on temperature and humidity, and they are easily deformed, they are subject to restrictions in the environment in which they can be used. Furthermore, upper '5L■
However, this method has the drawback that it takes time to cool down the lens after it is pressed, which increases the number of processing steps and increases the price. Furthermore, method (2) above has the disadvantage that the surface layer is made of acrylic resin, so it is easily scratched (and its characteristics change easily due to moisture absorption). It is difficult to apply a ΔR (anti-reflective) film that allows light incident on the lens to enter the lens without being reflected.

(Problems to be Solved by the Invention) As described above, the prior art methods (2) to (2) have specific drawbacks. SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a lens and a manufacturing method thereof that can manufacture an aspherical or Fresnel type lens with high precision and at low cost.

[Structure 1 of the invention (Means and effects for solving the problems) A first step of irradiating glass with laser light to soften the surface layer of the glass, and after this first step, pressing the glass into the desired lens shape. It consists of a second step of deforming and then cooling, making it possible to manufacture high-performance lenses with high precision and efficiency.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings (FIGS. 1 and 2).

In this embodiment, the first step is to manufacture a spherical glass lens 1 from glass, and one surface 2 of this lens 1 is
A second step of softening the surface layer 4 by irradiating the Oz-Silea light 3 (see Fig. 2), and holding the other surface 5 of the lens 1 with a lower mold 6, lowering the mold 7 in the direction of arrow R. The third step is to press the softened surface layer 4 into an aspherical surface.
(see Fig. 2), a fourth step of cold IJ1 of this pressed lens 1, and after this cooling, from the lower mold 6 upward! It consists of a fifth step of moving ill 7 to M and taking out lens 1. Therefore, the manufacturing of the lens 1 in the first step is carried out so that it becomes a spherical lens similar to the aspherical lens to be manufactured. In addition, the reason why the COt laser beam 3 is used in the second step is because the glass that is the material of the lens 1 is
This is because it absorbs COLL nose light 3 with an efficiency of 90% or more, and most of it is used for glass softening. Further, the thickness of the surface layer portion 4 that needs to be softened for press working is within several tens of um, corresponding to the deviation of the aspherical surface 8 from the spherical surface 9. Therefore, C from a COz laser device (not shown)
The Oz laser beam 3 is transmitted to the support base 1 via a mirror 10, for example.
The lens 1, which is maintained at ljl, is irradiated. Then, it is softened to a depth of about 10 μm to form a softened surface layer portion 4. Further, the lower mold 7 in the third step has a recess 12 corresponding to the spherical surface 5 of the lens 1. Further, the upper die 7 is provided with a recess 13 for press-molding the aspherical surface 8.

As described above, the lens of this embodiment and its manufacturing method are superior in environmental stability compared to plastic lenses because they are integrated with glass. Therefore, there is almost no deterioration in optical performance even when used in high temperature, high humidity, and low temperature environments. Further, since it is only necessary to soften the surface layer 4 having a depth of 10t and 1m, the time required for the fourth step of cooling can be shortened. Therefore, the number of man-hours is reduced and production efficiency is improved. Moreover, since it is an integrated glass lens, 1
! It has the advantage of being able to be coated with a protective film for one-width protection, leading to improved characteristics as an optical component.

In the above embodiment, an aspherical lens and its mounting method are illustrated, but it can also be applied to the production of a Fresnel lens 14 mainly used as a condenser + lens for condensing light, as shown in FIG. reactor.

The glass lens material in this case may be flat glass. This Fresnel lens 14 has a refracting surface that is not a continuous spherical surface but is made up of step-shaped concentric circles with different refractive angles. Therefore, the concave portion of the upper mold for press molding is also formed with grooves that are the inversion of the concentric circles on the steps. Further, in the above embodiment, the aspherical surface 8 is press-molded only on one surface 2 of the lens 1, but the aspherical surface 8 may be formed on both surfaces 2.5. In this case, after press forming the aspherical surface on surface 2, surface 5
It would be better to perform an aspherical surface on both surfaces 2.5 at the same time.
It is also possible to irradiate the ot laser with laser light 3 and perform press molding, especially an aspherical surface. Furthermore, the laser beam to be used is not limited to COx laser beam, but also l-1e −
Other laser beams such as Ne laser beam, argon ion laser beam, etc. may also be used. Furthermore, in the above embodiment,
Although the surface layer portion is only softened, a portion thereof may be melted.

[Effects of the Invention] The lens of the present invention and the method for manufacturing the same can be used to manufacture lenses, such as aspherical lenses and Fresnel lenses, which have conventionally been difficult to mount with glass, with high precision and high efficiency. It can be manufactured with. As a result, it becomes possible to manufacture a special optical lens that has stable optical performance and durability.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of a lens according to one embodiment of the present invention and its manufacturing method, and FIG. 3 is a sectional view of a Fresnel lens manufactured by a lens manufacturing method according to another embodiment of the present invention. . 1 glass lens (lens material), 3: COzOx laser light: surface h4 section, 8: aspherical surface, 14: Fresnel lens. 1st ILI entry burushi Norichika Ken 1st
Kikuo Takehana

Claims (5)

[Claims] (1) A lens comprising a main body made of glass and an optical refractive surface formed on the outside of the main body and serving as a press-molded surface. (2) It is characterized by comprising a step of irradiating a glass lens material with laser light to soften the surface layer, and a step of forming the softened surface layer of the lens material into an optical refractive surface by press molding. Lens manufacturing method. (3) The method for manufacturing a lens according to claim 1, wherein the optical refractive surface is an aspherical surface. (4) The method for manufacturing a lens according to claim 1, wherein the optical refractive surface is a Fresnel lens surface. (5) The method for manufacturing a lens according to claim 1, wherein the laser beam is a carbon dioxide laser beam.