JPH04251801A - Fungiproof antireflection film - Google Patents

Abstract

PURPOSE:To semipermanently suppress the generation of fungi on the surfaces of optical parts without contaminating the optical systems and without lowering the optical performance thereof. CONSTITUTION:An ITO film 8 (or In2O3 film) is formed as a 1st film in an effective luminous flux diameter part 3 on a substrate 7 of the optical element and the peripheral part 4 thereof. An MgF2 film 9 is then formed as a 2nd layer on the effective luminous flux diameter part 3 on the 1st layer, an ITO film 8 as a 3rd layer and an MgF2 film 9 as a 4th layer respectively thereon. Then, the ITO film 8 of the 1st layer having the excellent fungiproofness prevents the generation and advance of the fungi from the periphery of the holding part of the optical element.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold-proof anti-reflection film for preventing the growth of mold in various precision instruments, optical instruments, etc. made up of optical parts.

0002

BACKGROUND OF THE INVENTION Generally, in precision optical instruments such as microscopes, still cameras, electronic cameras, and video cameras, the growth of mold on the surfaces of optical elements may cause a decline in basic optical performance or poor appearance. In particular, the growth of mold within the effective luminous diameter of an optical element is a particularly important issue because it significantly impairs optical performance compared to other parts.

Conventionally, it has been thought that the most effective anti-mold measure is to fix various anti-mold agents near the optical system. For example, methods have been taken such as adding a fungicide to a paint and applying it to peripheral members of an optical system, or solidifying a fungicide and installing it around an optical element.

0004

[Problems to be Solved by the Invention] However, with the above-mentioned conventional anti-mold means, there is a limit to the expiration date of the anti-mold agent, and in order to maintain the anti-mold effect over a long period of time, it is necessary to add an anti-mold agent. If the amount is increased, there are problems such as recrystallization in the surrounding area and contamination of the optical system itself, as well as generation of odor. There have also been attempts to directly treat the surface of optical elements with antifungal agents, but this has not been put to practical use because it is difficult to maintain optical performance. Furthermore, we select materials that suppress the growth of mold from among anti-reflective coating materials,
Attempts have been made to use it in place of conventional materials, and although some results have been achieved, the necessary and sufficient effects have not been achieved.

The present invention has been made in view of such conventional problems, and is capable of semi-permanently suppressing the growth of mold on the surface of optical components without contaminating the optical system or degrading optical performance. The purpose of the present invention is to provide a mold-proof anti-reflection film that can be used as a mold-proof anti-reflective film.

[0006]

[Means for solving the problem] We focused on the fact that in many cases where optical components on which anti-reflection films are formed are actually damaged by mold, the damage is particularly noticeable on the outer periphery that holds the optical elements. . That is, as shown in FIG. 5, the optical element 1 is normally held by the frame 2 at its outer periphery. In FIG. 5, 3 indicates a luminous flux effective diameter portion of the optical element 1, and 4 indicates its peripheral portion. As shown in FIG. 6, which is an enlarged view of area 5 shown in FIG.
In many cases, they propagate from the frame 2 side through the peripheral part 4 of the optical element 1 toward the center part of the optical element 1. This is mold 6
The main reason for this occurrence is thought to be that mold and bacteria are more likely to adhere to rough surfaces and parts with complex shapes. Therefore, by setting a strong anti-mold region in the peripheral part 4 of the optical element 1, it becomes possible to protect the luminous flux effective diameter part 3 in the central part of the optical element 1 from mold 6.

The conventional treatment of the frame 2 with chemicals is undesirable in terms of cost and side effects on the optical element 1. Therefore, the inventor of the present invention provided anti-mildew properties to the peripheral part 4 of the effective luminous diameter part 3 of the optical element 1 at the same time as forming an antireflection film, so that the effective luminous diameter part of the optical element 1 from the peripheral part 4 We have developed a method to prevent mold 6 from entering 3.

That is, in order to achieve the above object, the present invention provides an anti-reflection coating material having excellent anti-fungal properties as a first layer on the surface of a substrate of an optical element, not only in the effective luminous diameter area but also in the peripheral area thereof. The film was formed over a wide area, and from the second layer onward, an antireflection film was formed within the effective diameter of the light beam, as in the conventional case. Specifically, starting from the substrate side of the optical element, an indium oxide (In2O3) film or an indium tin oxide compound (ITO) film is formed as a first layer over a wide area up to the periphery of the luminous flux effective diameter, The second and subsequent layers are formed within the luminous flux effective diameter portion.

[0009]

[Function] In the mold-proof anti-reflection film of the present invention having the above structure, the mold-proof film located between the member such as the frame holding the optical element and the area having the anti-reflection function of the optical element is Prevents mold from growing around the holding part. In2O3 or ITO exhibits the antifungal effect. This involves applying live mold to the surface of the specimen, culturing it for a certain period of time (usually 3 weeks) in an environment suitable for mold growth, and then checking the growth status to see if it has anti-mold properties. It has been confirmed that the product has anti-mold properties through a culture test, which determines that it has anti-mold properties if there is no growth of mold on untreated products. Due to the structure of the membrane, when it is exposed on the outermost surface as in the present invention, the antifungal effect is great.

0010

[Embodiment 1] As shown in FIG. 1, an ITO film 8 is applied as a first layer to a light beam effective diameter portion 3 and its peripheral portion 4 on the surface of a substrate 7 made of glass of an optical element. A film was formed by vacuum evaporation using a holder. Next, a MgF2 film 9 is applied as a second layer, an ITO film 8 is applied as a third layer, and an MgF2 film 9 is applied as a fourth layer to the effective diameter portion 3 of the luminous flux on the first layer. A film was formed by vacuum evaporation using the above method to obtain a mold-proof anti-reflection film.

[0011] In vacuum evaporation, the inside of the evaporation chamber is evacuated to a evaporation vacuum level of 1 x 10-5 Torr, and the substrate temperature is set to 150~150°C.
In addition to setting the temperature to 200℃, O2 was used during ITO deposition.
Gas is introduced into the chamber and the degree of vacuum is 1×10-4To.
rr, and EB (electron gun) evaporation was performed. Further, during MgF2 deposition, EB deposition was performed without introducing gas.

Table 1 shows the film structure and film thickness of the anti-mildew antireflection film of this example.

[0013]

[Table 1]

[0014] The anti-fungal anti-reflective film of this example and the ITO
When a mold culture test (temperature 30°C, humidity 95%) was conducted for three weeks (first time) with an untreated membrane without a membrane (comparative example), it was found that While the sample did not develop mold, mold did develop in the comparative example. Further, in this example, no deterioration in optical performance was observed even after 3 weeks. Furthermore, when each of the above samples was washed and tested again for the second time, the mold-proofing performance showed the same results as the first time. It has also been revealed that it has very stable anti-mold performance.

Table 2 shows the results of the above culture test.

[0016]

[Table 2]

Incidentally, FIG. 2 shows the reflectance characteristics of the anti-mildew anti-reflection film of this example. Figure 2 shows wavelength (nm) on the horizontal axis and reflectance (%) on the vertical axis.As can be seen from this figure, the anti-mildew anti-reflective film of this example has good reflectance characteristics. have.

[0018]

[Example 2] A mold-proof antireflection film was formed on a glass substrate 7 as shown in the film structure and film thickness shown in FIG. 3 and Table 3. This example differs from Example 1 as follows:
It has a two-layer structure. Other vapor deposition conditions and the like are the same as in Example 1.

[0019]

[Table 3]

[0020] When the mold-proof anti-reflective film of this example was subjected to the same mold culture test as described above, the mold-proofing effect was further enhanced compared to Example 1, and no mold was generated at all. . Note that the reason for changing the film thickness was to maintain antireflection performance.

[0021]

Example 3 A mold-proof anti-reflection film was formed on a glass substrate 7, as shown in FIG. 4 and Table 4, showing the film structure and film thickness. This example differs from Example 1 as follows:
The first layer and the third layer are made of In2O3 film 10,
The second layer and the fourth layer are made of SiO2 film 11. Other vapor deposition conditions and the like are the same as in Example 1.

[0022]

[Table 4]

[0023] When the same culture test as above was carried out for the anti-mold anti-reflective film of this example, the anti-mold effect was further enhanced compared to Example 1, and no mold was generated. Note that the reason for changing the film thickness was to maintain antireflection performance.

[0024]

Effects of the Invention As described above, according to the anti-mold anti-reflection film of the present invention, the first anti-reflection film is coated on the substrate of an optical element in order from the substrate side.
As a layer, an In2O3 or ITO film was formed over an area wider than the effective diameter of the luminous flux, and the second and subsequent layers were formed within the effective diameter by vacuum evaporation, so that the part with high anti-fungal performance was formed over a certain area of the optical beam. It can be installed around the effective luminous diameter of the element, thereby preventing mold from advancing from the outer periphery. Moreover, since no chemicals are added, there is no contamination of the optical system, and the growth of mold on the effective diameter surface of the optical element can be suppressed semi-permanently without deteriorating optical performance.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a mold-proof antireflection film of Example 1 of the present invention.

FIG. 2 is a graph showing the reflectance of the anti-mildew anti-reflective film of Example 1 of the present invention.

FIG. 3 is a side view showing a mold-proof antireflection film of Example 2 of the present invention.

FIG. 4 is a side view showing a mold-proof antireflection film according to Example 3 of the present invention.

FIG. 5 is a vertical cross-sectional view showing the main parts of the optical component.

FIG. 6 is an enlarged vertical cross-sectional view of a main part in FIG. 5;

[Explanation of symbols]

1 Optical element 3 Effective diameter of luminous flux 4. Surrounding area 6 Mold 7 Board 8 ITO film 9 MgF2 membrane 10 In2 O3 film 11 SiO2 film

Claims (1)

[Claims] Claim 1: In a mold-proof antireflection film formed on the surface of a substrate of an optical element, an indium oxide film or an indium oxide tin oxide compound film is formed as a first layer on the luminous flux effective diameter portion and its periphery on the substrate surface. 1. A mold-proofing antireflection film, characterized in that a second layer and subsequent layers are successively formed on the first layer at the luminous flux effective diameter portion.