JPH03249601A - Optical element with protective film and production thereof - Google Patents

Abstract

PURPOSE:To make improvement in weatherability and antifogging property by applying a fluorine lubricant as a protective film on the surfaces of optical elements consisting of a glass material. CONSTITUTION:The liquid fluorine lubricant 3 is applied on the surfaces of the optical elements 1, 2 to form the protective film consisting of the fluorine lubricant 3. Namely, the decrease in surface energy and the improvement in water repellency and oil repellency are resulted. The fluorine lubricant 3 is chemically adsorbed on the surface of glass or plastic, this lubricant improves the adhesiveness of the protective film and the optical elements 1, 2 without impairing the surface roughness of the optical elements 1, 2. The sticking of steam and oily stains to the surface of the optical elements is substantially prevented and the surfaces of the optical elements having various characteristics, such as weatherability and antifogging property, are obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical element having excellent weather resistance, antifouling properties, or antifogging properties, and a method for manufacturing the same.

[Conventional technology]

Depending on the environment in which the optical element is used, the surface of the optical element may become cloudy due to water vapor, or dust may adhere to the surface of the element, resulting in minute scratches on the surface of the optical element. As a result, optical characteristics may deteriorate. Therefore, it is necessary to prevent the above problem from occurring by forming a protective film on the surface of the optical element. Furthermore, plastic materials are often used as materials for optical elements because of their excellent moldability. However, since plastic materials generally have poor weather resistance compared to glass materials, it is necessary to form a protective film on the surface of the plastic optical element to ensure weather resistance. As described above, it is necessary to form a protective film on the surface of an optical element in order to improve its properties such as weather resistance and anti-fogging properties.

As a publicly known example related to the present invention, JP-A-55-2802
No. 3 and Japanese Patent Application Laid-Open No. 56-25701.

[Problem to be solved by the invention]

Conventionally, resin materials such as vinyl polymers, melamine resins, and silicone resins are often used as protective film materials. Further, as a method for forming a protective film, a coating and drying method is often used, but since the surface of an optical element is extremely rough, there is a problem that the protective film is easily peeled off. Therefore, a method has been devised to improve the adhesion between the protective film and the optical element surface by forming an annular groove with a depth of 0.5 μm or more on the surface of the optical element (for example, Japanese Patent Laid-Open No. 55-28023
(see issue). However, this method is unreasonable because it goes to the trouble of roughening the highly smooth optical surface. Further, in the case of optical elements using plastic materials, a method of applying a crosslinked cured resin is often adopted in order to improve the weather resistance of the element. However, with this method, it is difficult to control the protective film thickness. Therefore, methods have been devised to form a silicone protective film while controlling the thickness of the protective film using a vacuum evaporation method (for example, JP-A-56-257
However, this method has the problem of poor mass productivity. SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide an optical element having excellent weather resistance, antifogging properties, and other properties, and a method for manufacturing the same.

[Means to solve the problem]

The present invention is characterized in that a fluorine-based liquid lubricant is applied to the surface of an optical element to perform surface modification.

Since the optical element of the present invention has a protective layer made of a fluorine-based lubricant formed on its surface, its surface energy is lowered and its water repellency and oil repellency are improved. Since fluorine-based lubricants are chemically adsorbed onto the glass or plastic surface, they can improve the adhesion between the protective film and the optical element without impairing the surface roughness of the optical element. In order to further improve the adhesion between the protective film and the optical element, the optical element can be surface-treated with a silane coupling agent, etc., and then a fluorine-based lubricant can be applied. It can be changed arbitrarily by changing the concentration of the fluorine-based lubricant. The concentration of the fluorinated lubricant is controlled by diluting it with an appropriate solvent. Furthermore, this protective film can easily be made to have a uniform thickness on the order of several dozen people. The protective film is formed using the dipping method, and the coating method is used to form the protective film.
It can be easily performed by any particular method such as spray method, spin coating method, vacuum evaporation method, etc. 6 [Operation] Fluorine-based lubricants are strongly chemically adsorbed to the surface of optical elements, so there is no problem of peeling. There isn't. When applying a fluorine-based lubricant, first clean the element surface with a potassium hydroxide solution, dry it, and then treat the surface with a silane coupling agent, etc., then apply the fluorine-based lubricant, and then dry it in nitrogen gas. Adhesion is further improved by irradiating with ultraviolet light. Moreover, the same effect can be obtained by heating in a nitrogen atmosphere instead of exposure. The surface energy of the optical element produced by the above method is extremely small, and the water repellency and oil repellency are improved. Therefore, water vapor and oil-based dirt rarely adhere to the surface of the optical element, resulting in improved weather resistance and
It is possible to realize an optical element surface having excellent properties such as antifogging properties.

〔Example〕

The present invention will be explained below with reference to Examples.

Example 1. (Antifouling properties) In this experiment, a liquid lubricant made of a fluorine-containing azide compound was applied to the surface of the polymer, and its properties were evaluated.

The sample was made by coating a glass substrate with a paint consisting of phenol resin, epoxy resin, and polyvinyl butyral resin.
It was heated and cured at 00°C for 2 hours to form a polymer coating film. A Freon solution of a fluorine-containing azide compound was applied to the above polymer coating film, and a 600W low-pressure mercury lamp was used in a nitrogen atmosphere for 1 hour.
After time exposure, antifouling treatment was performed by ultrasonic cleaning in Freon for 5 minutes. As a comparative example, the antifouling property of a polymer coating film not coated with a fluorine-containing azide lubricant was also investigated. The degree of soiling was evaluated by staining each sample with soot, wiping it off with a cloth, and comparing the amount of soot remaining on the surface of the sample. As a result, the samples coated with the fluorine-containing azide lubricant showed almost no stains, whereas the samples to which the fluorine-containing azide lubricant was not coated were completely black stained. Furthermore, in the above antifouling treatment, a similar effect was observed when heating was performed at 130''C for 30 minutes in a nitrogen atmosphere instead of exposure.

Example 2. (Water repellency) Water repellency was evaluated by measuring the contact angle of a polymer coating film formed in the same manner as in Example 1 and a polymer coating coated with a fluorine-containing azide lubricant. N-hexadecane was dropped onto the sample surface, and the contact angle was measured.

The sample coated with fluorine-containing azide lubricant was 70-8
The sample had a contact angle of 0 degrees, whereas the sample to which the fluorine-containing azide lubricant was not applied had a contact angle of around 7 degrees. From this, it was found that the sample coated with the fluorine-containing azide lubricant had better water repellency.

Example 3. (Anti-fogging property) A sample in which a fluorine-containing azide lubricant was applied to the surface of a glass flat plate was left in an atmosphere of 80% at 20° C. for 10 seconds, and the degree of fogging on the sample surface was examined.

As a comparative example, a similar experiment was conducted using a flat glass plate to which no lubricant was applied.

In the case of glass, the adhesion of a lubricant is slightly inferior to that of a polymer, so the lubricant was applied to the glass surface after surface treatment using a silane coupling agent in advance. The sample preparation method is as follows. First, 10%
The glass sample was immersed in an aqueous potassium hydroxide solution for 48 hours and then washed with water.

dry. Next, a silane coupling agent H(CH,)i, S i (○CH3) is applied to the surface of this sample, heated at 100° C. for 30 minutes, and then washed with methanol. A fluorine-containing azide lubricant with a concentration of 2% was applied to the surface-treated sample as described above, and the sample was heated at 600 W using a low-pressure mercury lamp in a nitrogen atmosphere.

Exposure is performed for 1 hour, and ultrasonic cleaning is performed for 5 minutes in Freon to remove excess lubricant remaining on the sample surface. When the sample prepared in this way was left in the above atmosphere and the degree of cloudiness on the sample surface was examined, it was found that the sample without lubricant developed cloudiness over the entire surface, while the sample without lubricant The sample coated with it had almost no fogging.

Example 4. (Effect as a mold release agent) When an optical element is manufactured by a replica method or the like, it is often difficult to remove the exposed optical element from the concave mold. Therefore, in this example, a lubricant was used as a mold release agent. The experiment was conducted as follows. Glass square rods measuring 5 square meters and 25 square meters in length were glued together using ultraviolet curing resin.

Next, a tensile test was conducted using this sample to determine the adhesive strength between the glass surface and the ultraviolet curing resin. Since the adhesive strength is affected by the surface roughness of the joint, all the joint surfaces of the glass rods were made to have a mirror finish so that there was no difference in the finished surface roughness. After applying a fluorine-containing azide lubricant to the joint surfaces, a tensile test was performed using a tensile test piece made by laminating glass rods together using an ultraviolet curing resin and a tensile test piece made by laminating glass rods together without applying any lubricant. I did it.

As a result of comparing the tensile loads, it was found that the tensile test piece prepared by applying lubricant to the joint portion was less than 1/100th the size of the test piece that did not contain lubricant.

Example 5. (Application to molded lens production) Next, lenses were actually produced using the replica method.

The mold releasability of the fluorine-containing azide lubricant was confirmed. FIG. 1 shows the lens manufactured in this example. In FIG. 1, various dimensions such as the radius of curvature are exaggerated in order to clearly show the lens shape. This lens is a hybrid aspherical lens having a structure in which an aspherical lens 2 made of ultraviolet curing resin is laminated on the surface of a spherical lens 1 made of glass, and a protective layer 3 made of a fluorine-containing azide compound is further formed on top of the aspherical lens 2. .

Figure 2 shows the manufacturing process of this lens. As shown in FIG. 2(a), a fluorine-containing azide lubricant 3 is applied to the surface of a mold 4 having an aspherical shape in which a concave surface is to be produced. Since this is used as a mold release agent, the film thickness may be approximately 1000 mm or more.

Next, as shown in FIG. 2(b), the mold surface 4 is uniformly coated with an ultraviolet curing resin 5, and a glass spherical lens 1 is pressed thereon with a constant load W. Next, as shown in FIG. 2(c), the resin 5 is cured by irradiating it with ultraviolet rays for several minutes.
The aspherical shape is transferred to the surface of the glass lens 1. Furthermore, as shown in FIG. 2(d), the lens 6 with the resin 5 is extracted from the mold 4.

The lens 6 is immersed in the fluorine-containing azide lubricant 3 diluted to an appropriate concentration. Next, as shown in FIG. 2(e), this lens 6 is placed in a nitrogen atmosphere and exposed for one hour using a 600 W low pressure mercury lamp. Finally, Figure 2 (f)
Put the lens 6 in Freon 7, perform ultrasonic cleaning for 5 minutes, remove excess lubricant, and dry.

In step (d), the lens 6 with resin S could be easily extracted from the mold 4. For comparison, when a lens was manufactured in step (a) without applying the fluorine-containing azide lubricant 3 to the mold 4, it was found that the lens 6 could not be extracted from the mold 4 in step (d). It became impossible to proceed with the subsequent process. As can be seen from this result, fluorine-containing azide lubricant 3 was also highly effective as a mold release agent. In addition, if the film thickness of the lubricant 3 to be applied to the mold 4 in step (a) is selected to be appropriately large, it can be used as a mold release agent when removing the lens 6 from the mold 4 in step (d). Since the used lubricant 3 adheres to the lens surface and forms a protective film, it is possible to save the effort of newly applying lubricant 3 to the lens in step (d).

〔Effect of the invention〕

The optical element of the present invention exhibits excellent properties in terms of weather resistance and antifouling properties. Furthermore, the fluorine-based lubricant used in the present invention is
It is also sufficiently effective as a mold release agent when manufacturing optical elements by molding or the like. According to the present invention, for example, by manufacturing an optical element using a replica method and further forming a protective film using a dip method, it is possible to easily manufacture an optical element having a complicated shape such as an aspherical lens. It becomes possible to improve the weather resistance and water resistance of the lens.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of a lens according to the present invention, and FIG. 2 is a schematic diagram showing an embodiment of a method for manufacturing a lens according to the present invention. DESCRIPTION OF SYMBOLS 1... Glass spherical lens, 2... Ultraviolet curing resin aspherical lens, 3... Fluorine-containing azide lubricant, 4...
・Mold, end: Ultraviolet curing resin, 6: Lens with an aspherical shape transferred to the glass lens surface, 7: Freon. (Second! Diagram (f)

Claims (1)

[Claims] 1. An optical element with a protective film, characterized in that a fluorine-based lubricant is coated as a protective film on the surface of an optical element made of a glass material, a plastic material, or a combination of these materials. 2. The optical element according to claim 1, wherein a fluorine-containing azide compound is used as the fluorine-based lubricant. 3. The above-mentioned fluorine-containing azide compound is characterized by having a structure in which the basic skeleton is a partially or entirely fluorinated alkyl chain or polyether chain, and an azide group is present via a non-fluorine functional group. The optical element according to claim 2. 4. The above fluorine-containing azide compound has the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (However, A is -CH_2CH_2-, ▲ Mathematical formulas, chemical formulas, tables, etc.) There is▼, or -CO_2-
B is a functional group represented by -CONHL- (L represents an aromatic group), n is an integer from 3 to 20, m is an integer from 0 to 30, i and j are each 0 or 1 and 1≦i
+j≦2, r is an integer from 1 to 100,
t is 2 or 3, and t's of 2 and 3 may be contained in the molecule at the same time, and p and q are each from 1 to 100.
is an integer up to . 4. The optical element according to claim 3, wherein the optical element is a fluorine-containing azide compound represented by: 5. A method for manufacturing an optical element according to any one of claims 1 to 4, wherein the optical element is manufactured by cutting, grinding, polishing, molding including injection molding, a replica method, or a combination thereof. A method for manufacturing an optical element, comprising forming a protective film by applying the lubricant on the surface. 6. After soaking the optical element in the lubricant for a predetermined time,
6. The method of manufacturing an optical element according to claim 5, wherein the protective film is formed by pulling the optical element out of the lubricant and drying it for a predetermined period of time. 7. The optical element manufacturing method according to claim 5, further comprising spraying the lubricant onto the surface of the optical element to form a protective film. 8. The method of manufacturing an optical element according to claim 5, wherein the lubricant is attached to the surface of the optical element by a vacuum deposition method.