JPH05107407A - Optical mirror - Google Patents

Abstract

PURPOSE:To provide an optical mirror which can prevent its mirror surface from deteriorating its surface condition and from cracking, which is excellent in mass productivity and which is manufactured at a low cost. CONSTITUTION:A surface of a metal substrate 2 on which a mirror surface is to be formed is thereover with a first radiation cure type soft resin layer 4, and is then formed with a second radiation cure type hard resin layer 6 is formed. Further, a metal reflection film 5 made of aluminum or the like, is formed over the layer 6 in order to attain stress relaxation which is caused by variations in dimensions of the resin layers 4, 6 due to a change in temperature or humidity. Thereby it is possible to obtain an optical mirror 1 which may maintain the accuracy of the mirror surface 3 and which may prevent the mirror surface from cracking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical mirror, and more particularly to an optical mirror having an excellent reflecting surface property and a manufacturing method.

[0002]

2. Description of the Related Art As a conventional method for manufacturing an optical mirror, there is a method of cutting and polishing an iron-based hard metal, and a method of polishing after grinding, or a method of mirror-cutting an Al-based, Cu-based, and Ni-based metal. However, these processing methods have a large number of processing steps, and lack of consideration for mass productivity and reduction of manufacturing cost. Therefore, in Japanese Patent Laid-Open No. 2-161401,
A base material made of high-rigidity material is cut to create a wavy slope with a constant pitch, and a photosensitive resin is evenly applied to this wavy slope, and the flatness and specularity of this photosensitive resin are excellent. A transparent master member is brought into close contact with the photosensitive resin to expose it to light having a wavelength matching the absorption wavelength, the master resin is peeled off, and a high-reflectance member is vapor-deposited on the surface of the photosensitive resin for reflection. The surface (mirror surface) was formed.

[0003]

The above-mentioned prior art does not consider the difference in thermal expansion (contraction) and the difference in hygroscopic expansion between the metal substrate and the radiation curable resin due to changes in the temperature and humidity environment in which the mirror is used. There is a problem that cracks occur in the reflective film. An object of the present invention is to solve the above problems and provide an optical mirror having an excellent reflecting surface property and a manufacturing method.

[0004]

The above object is to form a soft radiation-curable resin layer on a metal substrate, and further provide a hard radiation-curable resin layer on the soft radiation-curable resin layer, A mirror surface is formed by a mother die that transmits radiation,
After curing the radiation curable resin layer by irradiation with radiation,
A metal reflective film is formed on the radiation curable resin layer.

[0005]

[Function] Generally, a molded product obtained by integrally polymerizing different materials has a difference in thermal expansion (contraction) due to a change in temperature and humidity and a difference in hygroscopic expansion, which causes warping, swelling, or cracking on the surface. There is a case. When the metal substrate is a highly rigid body, wrinkles may occur in the radiation curable resin layer. This is because a stress is generated between the metal substrate and the radiation curable resin layer due to the difference in thermal expansion (contraction) and the difference in hygroscopic expansion. Therefore, a soft radiation curable resin having a small Young's modulus (elastic coefficient) is provided as the first resin layer to relieve the stress, and a hard radiation curable resin layer is provided on the first resin layer to form a metal reflection film on the surface. If formed, an optical mirror free from warp, undulation and wrinkle can be obtained.

[0006]

EXAMPLES Examples of the present invention will be described below.

[Embodiment 1] A first embodiment according to the present invention is constructed as shown in FIG. That is, in the optical mirror 1, the first radiation-curable resin layer 4 is first formed on the surface of the metal substrate on which the mirror surface is formed, the second radiation-curable resin layer 6 is formed thereon, and further thereon. A metal reflection film 5 such as aluminum is formed to obtain a desired optical mirror surface. A method of manufacturing the mirror 1 is shown in FIGS. First,
A surface 8 forming a mirror surface of the metal substrate 2 is processed into an approximate shape of the final mirror surface 3 by an aluminum die casting method, and the surface roughness is 10 to 30 μm Rmax. On this mirror forming surface 8, 70 parts by weight of a soft radiation curing resin, poly-1,2 butadiene diacrylate (average molecular weight 2000) and 30 parts by weight of 1,6 hexanediol dimethacrylate were selected from the radiation curing resins shown in Table 1. A mixed resin of bisphenol A diglycidyl ether diacrylate resin 4 is supplied as shown in FIG.

[0008]

[Table 1]

Next, the radiation curable resin 4 is pressed by a glass mold 9 having a mirror surface 10 polished to a desired mirror surface shape and surface roughness (FIG. 4), and the resin 4 is thinned to a thickness of about 10 to 200 μm. Form the layers. After that, the glass mold 9 is irradiated with radiation, here, ultraviolet rays having a wavelength λ = 365 nm. The resin 4 cures in about 15 seconds at an ultraviolet intensity of 150 mW / cm ² .
During curing (during UV irradiation), pressure is applied in the thickness direction in order to prevent sink marks and deterioration in dimensional accuracy due to curing shrinkage of the resin. After curing, the glass mold 9 was removed (FIG. 5), and the hard radiation curable resin 6 and bisphenol A shown in Table 1 were prepared by the procedure shown in FIGS. 6 to 7, that is, basically the procedure shown in FIGS. Diglycidyl ether diacrylate was applied onto the soft radiation curable resin 4 layer to form a layer of 1 to 200 μm.
It is formed and cured by a glass mold 9 having a mirror surface forming surface 10 that is polished to a desired mirror surface shape and surface roughness. 600-2000 Å aluminum reflective film 5 by aluminum vapor deposition on the resin 4 on which the mirror surface is transfer molded
To form. This time, the evaporation method was adopted, but the sputtering method,
An ion plating method may be used.

Through the above steps, the optical mirror 1 having the desired mirror surface 3 shown in FIG. 1 is manufactured. The mirrors shown here are toric mirrors, but the same applies to plane mirrors, spherical mirrors, aspherical mirrors, toroidal mirrors, paraboloidal mirrors, ellipsoidal mirrors and the like. Further, although an aluminum die-cast product is used as the metal substrate, a processed product such as cutting or grinding made of another metal does not go beyond the scope of the present invention. As the material of the glass mold 8, quartz glass, which has a small absorption in the ultraviolet region, is desirable. As the soft radiation curable resin, 70 parts by weight of No. 4 resin hydrogenated poly 1,2 butadiene diacrylate (average molecular weight 2000) shown in Table 1 and 30 parts by weight of 1,6 hexanediol dimethacrylate were used. A mixed resin may be used, or as a hard radiation curable resin, No. 2 resin hydrogenated bisphenol shown in Table 1 may be used.
Le A ether diglycidyl ether diacrylate may be used.

[Second Embodiment] A second embodiment according to the present invention is constructed as shown in FIG. That is, on the surface of the metal substrate 2 on which the mirror is formed, the soft radiation-curable resin layer 6 shown in Table 1, 70 parts by weight of poly (1,2 butadiene diacrylate) (average molecular weight 2000) and 1,6 hexanediol dimethacrylate. A thin film of nitrocellulose or ethyl cellulose is formed on a layer of mixed resin with 30 parts by weight, and the metal reflection film 5 is formed on the thin film. This has the effect of [Example 2] and simplifies the manufacturing process. The manufacturing method is as shown below. First, as shown in FIG. 8, nitrocellulose or ethyl cellulose (both having an average molecular weight of about 10,0) was formed on the mirror surface 10 of the glass mold 9 for forming a desired mirror surface.
00) n-butyl acetate solution by spin coating etc.
A thin film 7 having a thickness of 0.01 to 1 μm is formed and dried by a natural drying method. Using the glass mold 9, a 10 to 200 μm layer of the soft radiation curable resin 4, that is, the resin of No. 3 shown in Table 1 is formed basically by the procedure shown in FIGS. Let it harden. Then, when the glass mold is removed, a thin film of nitrocellulose or ethylcellulose is formed on the hard radiation curable resin. 60 by aluminum deposition on a thin film of nitrocellulose or ethylcellulose
An aluminum reflection film 5 having a thickness of 0 to 2000Å is formed.
As a result, the optical mirror 1'shown in FIG. 2 is formed.
As the soft radiation curable resin, No. 1 shown in Table 1 was used.
Resin No. 4 Hydrogenated poly-1,2 butadiene diacrylate (average molecular weight 2000) 70 parts by weight and 1,6 hexanediol dimethacrylate 30 parts by weight mixed resin may be used.

[0012]

According to the present invention, since the soft resin is used for the portion to be bonded to the metal substrate, it is possible to prevent the deterioration of the surface quality of the mirror surface and the cracks due to the dimension change of the resin due to the temperature and humidity. .. Further, since the surface on which the reflective film is formed is made of a hard radiation curable resin, it is possible to reduce scratches on the surface of the optical mirror. Further, since the metal substrate forming the optical mirror main body can be duplicated by one mother die without performing mirror surface processing by machining, it is possible to reduce the processing man-hours of the optical mirror, and it is possible to reduce mass production and production costs. .. Further, in the machining, the surface properties vary, whereas in the present invention, the same mother die is used, so that the properties of the mirror surface hardly vary.

[Brief description of drawings]

FIG. 1 is a perspective view of a mirror according to the present invention.

FIG. 2 is a perspective view of the same mirror.

FIG. 3 is a cross-sectional view showing a method of manufacturing a mirror according to the present invention.

FIG. 4 is a cross-sectional view showing the same mirror manufacturing method.

FIG. 5 is a cross-sectional view showing the same mirror manufacturing method.

FIG. 6 is a cross-sectional view showing the same mirror manufacturing method.

FIG. 7 is a cross-sectional view showing the same mirror manufacturing method.

FIG. 8 is a cross-sectional view showing the same mirror manufacturing method.

[Explanation of symbols]

1, 1 '... Mirror 2 ... Metal substrate 3 ... Mirror surface 4 ...
Soft radiation curable resin 5 ... Metal reflective film 6 ... Hard radiation curable resin 7 ... Nitrocellulose or ethyl cellulose 9 ... Glass type

Claims (2)

[Claims] 1. In an optical mirror, a metal product processed into a mirror shape or a shape close to the mirror is used as a substrate, a soft radiation curable resin layer is formed on the metal substrate, and the soft radiation curable resin is further formed. A hard radiation-curable resin layer is provided on the layer, a mirror surface is formed by a mother die that transmits radiation, and the radiation-curable resin layer is cured by irradiation with radiation, and then a metal reflection film is placed on the radiation-curable resin layer. An optical mirror characterized by being formed into. 2. The optical mirror according to claim 1, wherein a soft radiation curable resin layer is formed on the metal substrate, and an ethyl cellulose or nitrocellulose resin layer is formed on the radiation curable resin. An optical mirror having a metal reflective film formed thereon.