JPS5913202A - Method for forming antireflection film on plastic lens - Google Patents

Abstract

PURPOSE:To form uniformly an organopolysiloxane resin film on a plastic lens by dip-coating twice said resin on said lens. CONSTITUTION:An organopolysiloxane resin soln. is coated on a plastic lens by subjecting the lens to at least one time of a stage consisting of coating the soln. first on the lens then curing the coating by heating then turning over the lens and coating the soln. thereon for the second time and curing the coating by heating. The pulling speed is kept at 100mm./min. The viscosity of the organopolysiloxane soln. in which the lens is dipped is set at 1-100cp.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of forming an antireflection coating on a plastic lens.

Conventionally, in order to provide an antireflection coating on a plastic lens, first, an organopolysiloxane resin film is coated on the plastic lens by a method such as pattern coating or spin cording, and after curing by heating, NgF2. ZrO,,A/,0
．． l The original inorganic antireflection coating made of SiO, etc. was applied.

The main purpose of the organopolysiloxane resin film is to improve the adhesion between the plastic and the inorganic antireflection film, prevent scratches on the plastic surface, improve hardness, and improve the impact resistance of the plastic. In addition, to further improve the scratch prevention, surface hardness, and impact resistance of plastics, an additional layer of 8i0.0.5 in thickness is added between the organopolysiloxane resin film and the original antireflection film. Alternatively, it has also been proposed to provide a layer of glass or the like.

However, since plastic lenses have curvature, it is difficult to apply organoborisiloxane to the lens surface to a uniform thickness. For this reason, it is common knowledge that the coating film thickness distribution is 2 to 4 times as large, and □In eyeglass lenses, etc., only the central part of the lens is used, and surface precision is not required as much. for,
Even under the above film thickness distribution, it was sufficiently usable.

However, when a plastic lens is used in an optical device such as a camera lens, the above coating film thickness distribution causes deterioration of the surface precision of the lens, making it difficult to obtain a usable plastic lens.

For this reason, a method has been proposed in which the pulling speed is controlled according to the lens curvature and a uniform film thickness is obtained by dip coating, but this method is difficult to control the film thickness and is only suitable for biconcave and biconvex lenses. It had drawbacks such as not being applicable.

An object of the present invention is to provide a method for uniformly forming an organopolysiloxane resin film on a plastic lens.

The present invention is characterized in that when dip-coating the organopolysilomylene resin on a plastic lens, it is coated twice.

More specifically, after the first application, a heat curing treatment is performed, and during the second application, the top and bottom of the plastic lens are reversed from those during the first application, and the lens is pulled up at the same speed of 10 owVmin or less.

In completing the present invention, the following experiments were conducted.

As shown in Fig. 1, in a container 3, a solution 1 prepared by diluting 25 times Nick Coat (trade name of an organopolysiloxane resin solution manufactured by Katsuta Kako) with Inglobil alcohol is used, and the acrylic plate 2 and the above solution surface are coated. Acrylic plate 2 by changing the angle θ of
is immersed in solution 1, and the pulling speed is 20ff + % nin.
The film was removed from the solution, cured by heating, and the thickness of the coating film was measured. Apply. Here, the angle between the upper surface of the acrylic plate 2 and the solution surface is set as (+), and the angle between the lower surface and the lower surface is set as (-).

8F! Figure 2 shows the results of measuring the thickness of the baked-in film formed on the acrylic board as described above. At an angle of -17 degrees, the coating film thickness was the lowest, and at an angle of 0 degrees, the coating film thickness was 0.7 μm.

It was also found that although the coating thickness varies depending on the pulling speed and viscosity, within a practical range, the relationship between the angle and the coating thickness tends to be as shown in FIG. 2.

Therefore, it is not possible to coat the lens 4 on the negative side of 5 as shown in FIG. For example, the distribution of the portal membrane thickness of a lens whose maximum angle between the lens and the liquid surface is 20 degrees is at most twice as large, reaching 5Flfti: when the maximum angle between the lens and the liquid surface is 140 degrees.

The coating thickness of the origanopolysilone-based resin must be at least 1 μm, so the film thickness distribution is 1 to 2 μm for a lens with a maximum angle of 20 degrees and 1 to 2 μm for a lens with a maximum angle of 40 degrees.
It becomes 3.5 μm, and the lens surface/surface precision deteriorates significantly.

□ The present invention is based on the above quantitative experiment, namely:
In the present invention, when a lens is immersed in an organopolysiloxane solution, it is first dipped from - in Fig. 3, and then immersed in b in Fig. 3, and coated twice. In this way, the accuracy of the distribution of the thickness of the organopolysilomylene film adhered to the surface of the plastic lens is improved. FIG. 4 quantitatively shows this situation. In the same figure, curve 7
Curve 8 shows the thickness of the coating that adhered to various parts of the plastic lens after the first application, curve 8 shows the thickness of the coating that adhered to various parts of the plastic lens after the second application, and curve 9 shows the thickness of the coating that adhered to various parts of the plastic lens after the second application. This shows the total thickness of the coating film attached to various parts of the plastic lens. According to this method, the coating film thickness becomes extremely uniform, and the maximum film thickness distribution for a lens where the maximum angle between the lens surface and the liquid level is 20 degrees is increased from twice that of the conventional method to 1.
．． You can see that it is 2 times and 7.

As described above, according to the present invention, an organopolysiloxane resin film having a uniform coating thickness was easily obtained on the lens surface.

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

An acrylic lens (the maximum angle between the lens surface and the liquid level was 20 degrees) was immersed in the organopolysiloxane resin solution, and the lens was coated at a lifting speed of 20 Wymin.

The lens was then heated at 80° C. for 3' hours to harden the organopolysiloxane. Next, as shown in FIG. 5, this acrylic lens was set upside down compared to the previous application, immersed in the solution under the same conditions as above, pulled out, and heat cured. To detect burn-in formed on the lens surface, the coating thickness distribution is measured with an interferometer, and changes in surface accuracy are zeroed out.
．． It was confirmed that it could be formed within 3 μm. 4th coating film thickness
Estimated from the figure, it was 1.4 μU ~ 17 capes.
4 Important points of the present invention are (1) performing the step of heating and curing after the second coating, then inverting the lens and heating and curing after the second coating, and (2) increasing the pulling speed. 10D
less than wny'rm i n, preferably 100 m$n
(3) The viscosity of the organoborisiloxane solution in which the lens is immersed is 1 to 1.
If 100 ep is applied, if a second coating is applied without heat curing after the second coating, the second coated layer will dissolve into the solvent and the desired coating thickness will not be obtained. .

Also, the speed at which the lens is pulled up from the solution is I D o
If it is pulled up faster than yVmin, the coating solution will flow on the lens surface and the coating thickness distribution will deteriorate.

As described above, according to the present invention, the distribution of the organopolysilomyzan resin film on the surface of the plastic lens is improved. Furthermore, the method of the present invention is applicable not only to biconcave and biconvex lenses but also to lenses having any curvature.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the pulling angle, Figure 2 is a diagram showing the relationship between the pulling angle and film thickness, Figures 6 and 5 are diagrams explaining the state in which a lens is immersed in a solution and pulled up, and Figure 4 is a diagram showing the relationship between the pulling angle and film thickness. The figure is a diagram for explaining the present invention in detail. 1... Solution 6... Container 4... Lenticular 1 self ke 2 A degree o (cALt) Fig. 5 Opening fulls, O (d+) Fig. 5

Claims (1)

[Claims] The process of immersing a plastic lens in an organopolysiloxane solution, pulling it out, heat-curing it, then inverting the lens, immersing it in the organopolysiloxane solution again, pulling it out, and heat-curing it again is performed at least once. A method for forming an antireflection film on a plastic lens, characterized in that: