CH670318A5 - - Google Patents

Description

DESCRIPTION The present invention relates to a method for producing an antireflection film from a plurality of layers, applied by evaporation of different vapor deposition substances in vacuo, on polydiethylene glycol diallyl carbonate lenses and spectacle lenses.

For some time now, attempts have been made to antireflect organic glasses, in particular so-called CR-39 glasses made of polydiethylene glycol diallyl carbonate, in such a way that they at least come close to the antireflection coating of crown in terms of intensity and color of the reflection.

So far, this has not succeeded.

The technology of multiple anti-reflective treatment of silicate glasses was adopted for such anti-reflective coatings, although here the CR-39 substrates with the various vapor deposition substances have to be evaporated in vacuo at a temperature below 100 ° C. Of the evaporation materials known to date, quartz (silicon dioxide Si02) is best suited to form a smudge-resistant and scratch-resistant layer at these relatively low temperatures, but to which at least one further layer, for example made of silicon monoxide (SiO), must be evaporated in order to to come close to the desired optical properties.

U.S. Patent No. 4,485,124 by the same inventor describes such an optical substrate in which the first inner layer of silicon monoxide (SiO) has a thickness of at least approximately V12 (one twelfth) of a quarter of a lambda and the second, outer Layer of silicon dioxide (SÌO2) has a thickness of at least approximately V4 (three-quarters) lambda, in each case based on the wavelength of visible light for which the human eye has the maximum sensitivity.

However, the reflection curve (reflection in percent to wavelength in nanometers) created in a known manner by spectral reflection measurement shows that CR-39 substrates with such or similar antireflection films still have very high residual reflections of a few percent per area, which does not meet today's quality requirements .

It is therefore an object of the present invention to provide a method for producing an antireflection film on lenses and spectacle lenses, which permits broadband anti-reflection with almost complete reflection reduction.

According to the invention, this is first achieved in that a first, optically inactive metal oxide layer is used as the adhesive layer; a second layer of an optically effective, high refractive index metal oxide; the third layer is a low-refractive index material; a fourth layer of another high refractive index metal oxide; and a low-refractive index material which is effective as a hard layer is vapor-deposited as the fifth layer.

This process can then be optimized

by evaporating a first, optically inactive metal oxide layer as an adhesive layer in a vacuum of at least approximately 1.33 x 10 ~ 3 Pa (1 x 10 ~ 5 TORR);

by evaporating a second layer of an optically effective, highly refractive metal oxide in a vacuum reduced by oxygen supply of at least approximately 2.66 x 10 ~ 2 Pa (2 x 10 "4 TORR);

by evaporating a low refractive index material which is effective as a dielectric in a again improved vacuum of at least 1.33 X 10 -3 Pa (1 X 10-s TORR) or better as a third layer;

by evaporating a fourth layer of another high refractive index metal oxide in a vacuum reduced by renewed oxygen supply of at least approximately 2.66 x 10 ~ 2 Pa (2x 10 "4 TORR) and in a again improved vacuum of at least 1.33 x 10 ~ 3 Pa (1 x 10 ~ 5 TORR) or better than a fifth layer, a low-refractive index material which is effective as a hard layer is evaporated;

all at a temperature in the range of about 50 ° C to 80 ° C and preferably the same evaporation rate.

The second layer with a thickness of parts of lambda quarters is advantageous; the third layer with a thickness of a quarter of a lambda; the fourth layer in a thickness of half a lambda; and the fifth layer with a thickness of lambda quarters, each based on the wavelength of the view5

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visible light, for which the human eye has the maximum sensitivity, evaporated.

Such a method then results in polydiethylene glycol dialyl carbonate lenses and spectacle lenses which, according to the invention, are distinguished by an antireflection film formed by a first, optically inactive metal oxide layer as the adhesive layer; a second layer of an optically effective, high refractive index metal oxide; a third layer of low refractive index material; a fourth layer of another high refractive index metal oxide; and a fifth layer of low refractive index hard material.

For such coated lenses and glasses, the spectral reflection measurement results in broadband anti-reflective treatment with a residual reflection of less than 0.5%. Such a high-grade coating has not yet been achieved, the last layer, which represents a quartz seal, of the antireflection film according to the invention giving the surface the greatest possible hardness and thus wear resistance. In addition, it can easily be checked that this residual reflection of the plastic glass coated according to the invention is at least approximately color-neutral. The self absorption is at a resp. such a lens. Glass zero.

The method according to the invention can be carried out using conventional vacuum vapor deposition systems. Such a system is described, for example, in the aforementioned US Pat. No. 4,485,124 by the same inventor, so that detailed information on this is superfluous.

The various vapor deposition substances can in any case be evaporated indirectly using electrically heated crucibles or boats, the crucibles or boats generally provided for each substance being able to be operated successively or according to a coupled time program. Cathode sputtering is also possible. Furthermore, the evaporation of the vapor deposition substances can take place by means of electron beam guns, where the electron beam emerging from a hot cathode is accelerated in an electric field and magnetically deflected onto the coating material, which evaporates suddenly at the point hit (US Pat. No. 4,485,124).

In addition to the anti-reflective effect and a color-neutral behavior, good adhesion to the substrate is important for an anti-reflective coating. This also applies here, whereby the known cleaning and pre-treatment methods as well as those of the intermediate and after-treatment are also used here.

Such a method, which can be used here, is described in the aforementioned US Pat. No. 4,485,124, according to which the objects inter alia. be exposed to direct infrared radiation inside the recipient at least before and during the vaporization processes.

Example:

For evaporation of the layers according to the invention on, for example, spectacle lenses made of the polydiethylene glycol diallyl carbonate mentioned in order to achieve the above-described Qua670 318

First of all, a number of such objects can be cleaned in a known manner after pre-cleaning, a several-hour outgassing in a vacuum at 95 ° C and a vacuum of 13.3 Pa (10-1 TORR) and an ultrasonic cleaning afterwards in the slide of the vacuum Steaming system are used. Then start the vacuum cycle while preheating the vacuum chamber. Subsequently, infrared radiation of the objects now rotating with the slides can also take place. This infrared radiation can be maintained until the end of the vacuum cycle. For example, after about 20 minutes of infrared radiation and with a vacuum of 2.66 x 10 ~ 2 Pa (2 x 10 "4 TORR), the objects can then be flushed with pure oxygen introduced into the vacuum chamber for about 4 minutes.

According to these or other or further measures for cleaning and pretreating the objects to be coated, the first layer is evaporated in a vacuum of at least approximately 1.33 x 10-3 Pa (1 X 10 ~ s TORR) or better at a temperature of approx 50 ° C to 80 ° C inside the chamber. This layer serves as a primer and consists of an optically inactive metal oxide, such as chromium (Cr). The layer thickness is only a few n.

The vacuum is then reduced to 2.66 X 10 ~ 2 Pa (2 x 10-4 TORR) by supplying oxygen and a second layer of an optically effective, highly refractive metal oxide such as zirconium oxide (Zr2Û3) is evaporated in the recipient while the internal temperature remains constant. Here, a layer thickness of parts of a lambda quarter is provided, based on the wavelength of visible light, for which the human eye has the maximum sensitivity.

The vacuum is then improved again to 1.33 x 10 ~ 3 Pa (1X 10 ~ 5 TORR) and a third layer of a low-refractive material, such as silicon dioxide (SÌO2), is evaporated to a thickness of a quarter of a lambda. This layer then acts as a dielectric.

Then the oxygen is again reduced to 2.66 x 10-2 Pa (2x 10 "4 TORR) by a further supply of oxygen and a fourth layer of another high-index metal oxide, such as titanium oxide (T (2O3), is evaporated with a thickness of half a lambda .

After again improving the vacuum to 1.33 x 10-3 Pa (1 x 10 ~ 5 TORR), a low-refractive index material which acts as a hard layer, such as silicon dioxide (S wirksO2), is evaporated with a thickness of λ-quarter; all this continues at a temperature of 50 ° C to 80 ° C and a preferably constant evaporation rate.

Then, if used, switch off the infrared radiation source and flood the system after a dwell time of a few minutes in order to be able to remove the coated objects.

Comprehensive measurements and tests have shown that the objects coated in the manner described above have an optical and mechanical quality that has never been achieved before, and fulfills all requirements.

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Claims (5)

670 318 - 2. The method according to claim 1, characterized in that in a vacuum of at least approximately 1.33 X10-3 Pa (1 x 10 ~ 5 TORR) or better, a first, optically inactive metal oxide layer is evaporated as an adhesive layer; that a second layer of an optically effective, highly refractive metal oxide is evaporated in a vacuum of at least approximately 2.66 x 10-2 Pa (2 x 10 ~ 4 TORR) reduced by the supply of oxygen; that a low refractive index material which is effective as a dielectric is evaporated in a again improved vacuum of at least 1.33 x 10-3 Pa (1 x 10 "5 TORR) or better than third layer; that a fourth layer of another highly refractive metal oxide is evaporated in a vacuum of at least approximately 2.66 X 10 ~ 2 Pa (2x 10 "4 TORR) reduced by renewed oxygen supply, and that in a again improved vacuum of at least 1.33 x 10 ~ 3 Pa (1 x 10 ~ 5 TORR) or better than a fifth layer, a low-refractive index material which is effective as a hard layer is evaporated; all at a temperature in the range of about 50 ° C to 80 ° C and preferably the same evaporation rate. 2nd PATENT CLAIMS 1. Process for producing an anti-reflective film from several layers applied by evaporation of different vapor deposition substances in a vacuum on polydiethylene glycol diallyl carbonate lenses and spectacle lenses, characterized in that a first, optically inactive metal oxide layer is used as the adhesive layer; a second layer of an optically effective, high refractive index metal oxide; the third layer is a low-refractive index material; a fourth layer of another high refractive index metal oxide; and a low-refractive index material which is effective as a hard layer is vapor-deposited as the fifth layer. 3. The method according to claim 2, characterized in that the second layer in a thickness of parts of lambda quarters; the third layer with a thickness of a quarter of a lambda; the fourth layer is half a lambda thick; and the fifth layer is vapor-deposited to a thickness of a quarter of a quarter, in each case based on the wavelength of visible light for which the human eye has the maximum sensitivity. 4. Polydiethylene glycol diallyl carbonate lenses and glasses with an anti-reflection film, produced by the method according to claim 3. 5. Lenses and spectacle lenses according to claim 4, characterized by an anti-reflection film, formed by a first, optically non-acting metal oxide layer as an adhesive layer; a second layer of an optically effective, high refractive index metal oxide; a third layer of low refractive index material; a fourth layer of another high refractive index metal oxide; and a fifth layer of low refractive index hard material.