JPS5993401A - Optical product having non-hygroscopic film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to articles having a non-hygroscopic coating, particularly articles having a mixed metal oxide layer in which the coating has a low hygroscopicity.

US Pat. No. 3,03≠, 5i', 24 discloses the use of rare metal oxides and protective coatings for optical and other purposes. A table is shown in column j of this patent, and column a1 lists a number of substances, including samarium oxide. However, U.S. Pat. Optical coatings are required to be non-hygroscopic; in other words, hygroscopic properties do not substantially change the optical properties (wavelength change).
wave lengthshift).

It is an object of the present invention to provide a product with a non-hygroscopic coating.

Another object of the present invention is to provide a product having a coating of the aforementioned character which is substantially free of wavelength change in the presence of moisture. ) Another object of the present invention is that the material utilized to produce the ruptured membrane is evaporated by electron beam evaporation (electron beam evaporation).
fractionation during fractionation
e) To provide a product having a coating of the aforementioned characteristics which produces a film which is chemically homogeneous throughout its thickness without any oxidation.

Another object of the invention is to provide a product having a coating of the above character which has a low water vapor absorption.

Another object of the invention is to provide an article having a coating of the character described above which is stable when exposed to a Moist Fi 111 atmosphere.

Other objects and features of the present invention will become apparent from the following description in conjunction with the drawings.

In general, products typically have predetermined optical compatibility characteristics (op
tlcal response character
at least 7 having a non-hygroscopic coating with
An optical type consisting of a substrate with two surfaces. The optical coating encloses at least seven mixed metal oxide layers having metal components of at least one lanthanide series metal and at least seven transition or semiconducting metals. The mixed metal oxide layer is characterized by low hygroscopicity, so that there is minimal wavelength change in the coating in the presence of moisture. The lanthanide 7 metals are samarium and reed, and the transition or semiconducting metal is titanium.

In particular, products with a non-hygroscopic optical coating thereon are subject to 7.3
−． It consists of a substrate 11 made of a suitable material, such as glass, having a refractive index of 2 and having spaced apart optical surfaces 12.13. Optical coating 14 is supported on surface 13. As shown, the coating 14 is a low index material (l
ow Index material) and high index material (
hlgh Index material) Consists of a large number of formed layers. Thus, the layers 16, 17, 18 counting from the surface 13 are made of a suitable type of low index material, for example silicon dioxide (810
2) and layers 21, 22 and 23 are formed of a high index material, preferably a mixed metal oxide of the invention as described below, having a refractive index of about λ,O.

Seven mixed metal oxides that are particularly suitable for high index materials in coatings 14 of the character described above are mixtures having a metallic component of at least one lanthanide series metal and at least seven transition or semiconducting metals.

For example, the lanthanide-freeze gold I14 can be limerium oxide and the transition or semiconducting metal can be titanium dioxide.

It has been found that it is preferable to produce a mixture of selected materials, such as samarium oxide and titanium dioxide, in a form that can be vaporized without fractionation by an electron gun. It has been discovered that this can be achieved by mixing suitable quantities of one of these materials, for example by utilizing ≠7 moles of titanium dioxide and j1 moles of dimarium oxide.

The selected substances are, for example, 3.2. ! ; it is produced in the form of a powder, such as a fine powder, which passes through the mesh. The powdered materials are mixed in a suitable device, such as a rotary blender. The mixed material is then processed in a suitable pelletizing machine 6.33
It is formed into small pellets having a suitable diameter, such as 1/4t inch.

After the pellets are formed, they are loaded into a furnace which is heated with an electron beam. What about substances? As it melts, the molten material is drawn out of the melt so that it solidifies as it is drawn out of the melt, forming a pre-melted cell ingot of mixed metal oxide material. These ingots are utilized to vaporize the mixed metal oxide material onto the substrate in a suitable device, such as an electron gun device, to provide a coating of the type described below.

Although it has been discovered that it is desirable to form mixed metal oxides into ingots, it is also possible to utilize the two materials separately,
It should be recognized that it is also possible to charge them to the boxwood as a powder in the desired amount and evaporate them directly.

However, this is somewhat undesirable as the powder is difficult to handle and tends to migrate away from the coating equipment.

In addition, it has been found that it is very easy to determine the quality of the material deposited on the substrate by forming pellets and then forming the pellets into ingots. Depositing the material in this manner allows the mixed metal oxide material to not fractionate during electron beam evaporation, thereby producing a film that is chemically and optically homogeneous through its thickness.

It has been found that in the formation of mixed metal oxide layers, the amount of spatter from materials that are thrown off during electron beam evaporation, in addition to materials that do not fractionate during evaporation, is minimal. In the manufacture of a coating such as the ruptured membrane 14, alternating layers of a low index material such as silicon dioxide or fused/liquor having a refractive index of /, lI-B are combined with alternating layers formed of the aforementioned mixed metal oxides. Then, it is evaporated onto the surface 13. Other low index materials such as magnesium fluoride (MgF2) and aluminum oxide (At203) are used in the coating in place of fused silica.

In evaluations of such film rupture or multilayer deposition, it has been found that the mixed metal oxides form films with low water absorption, and that the mixture itself is stable when exposed to a humid atmosphere. ) Coatings with such mixed metal oxide layers exhibit virtually no wavelength change in optical properties when exposed to a humid atmosphere.

This is done by subjecting such a multilayer coating formed from mixed metal oxides and molten metal to a temperature of 25° C. and a relative humidity environment of 2.
≠ Measured by time insertion and exposure. No significant change in wavelength was observed due to moisture absorption. Similarly, after 2≠ hours in a humid atmosphere, the membrane ruptures were fired to drive out moisture to determine whether changes in wavelength occurred during the firing process. No moisture was observed indicating that no moisture was absorbed by the coating during the time of exposure to a humid atmosphere. This lack of change when exposed to a humid atmosphere is completely surprising and is particularly useful for many applications of products with optical coatings, such as edge cover filters typically used in optical fiber systems. (edge cover filter) provides highly desirable results. In such filter applications, even the smallest change, such as 70 nanometers, can be applied to such an edge filter.
) can be very detrimental to the effectiveness of Other applications for this non-hygroscopic coating are in band pass filters and reflection shielding.

Invariance due to moisture absorption is extremely important when attempting to separate two closely spaced wavelengths. This is particularly clear when considering the reflection performance of the edge filter shown in the -1 diagram.

Filter 7-L in FIG. 2 is a multilayer filter that uses cerium oxide and titanium dioxide as mixed metal oxides as a high index material, and silicon dioxide or molten warping force as a low index material. Figure 3 shows its design (de, s
lgn).

By considering the curves in Figure 2 and considering the separation of two wavelengths, one at 1 theta nanometer and the other at ♂ 30 nanometers, we find that at f60 nanometers, the edge filter is It can be seen that more effective transmission occurs in the nanometer range. f, 20
At nanometers, optical energy is substantially reflected, whereas at fjO nanometers it is substantially transmitted. lol
It can be seen that if r<t, a wavelength change of 10-20 Notemeters in the edge filter will make it impossible for the edge filter to keep the two wavelengths separated. Thus threads such as those in which edge filters are used will not work properly.

-111 This reinforces the need for optical coatings that are non-hygroscopic and have virtually no spectral performance when exposed to humid atmospheres.

The aforementioned g! ! , it can be seen that an optical coating is disclosed that is particularly useful in articles of manufacture for edge filters, bandpass filters, and similar types of optical devices, which optical devices are particularly useful when the coating is exposed to a humid atmosphere. It is desirable to provide a predetermined spectral characteristic that does not change.

[Brief explanation of drawings]

In the accompanying drawings, FIG. 1 is a design for membrane rupture of a product having a coating of the present invention, FIG. 1 is a chart showing the spectral performance of the coating of the design shown in FIG. 7, and FIG. Indicates a special design used for 1 Indication of case 1982 Patent application No. 126828 28 Title of invention Optical product with non-hygroscopic coating 3 Person making amendment Relationship with case Applicant 4 Attorney 5 Date of amendment order October 25, 1988 Day 5-

Claims (1)

[Claims] / In an article for use in the optical field, a substrate having at least seven surfaces and an optical coating supported by the surfaces, the optical coating having predetermined spectral properties. and includes at least seven mixed metal oxide layers having a metal component of at least one Lanternleys metal and at least seven transition or semiconducting metals, wherein the mixed metal oxide is non-hygroscopic and wettable. The above-mentioned product is characterized in that it shows virtually no spectral changes in the atmosphere. The above-mentioned Rantartonries metal is samarium,
The article of claim 1, wherein said transition or semiconducting metal is titanium. 3. The product of claim 1, wherein the coating is a multilayer coating in which one layer is formed of a high index material and the remaining layers are formed of a low index material. Hiroshi The product of claim 3, wherein the high index material layer is a mixed metal oxide layer. 7. The product of claim 7, wherein said mixing table & oxide coating comprises about ≠7 moles of titanium dioxide and about j1 moles of samarium oxide.