JPH03196001A - Multilayered film type interference filter with no substrate and production thereof - Google Patents

Abstract

PURPOSE:To form a multilayered film type interference filter with no substrate and to extend the field of application of the filter by forming an etchable separating layer on a substrate and a multilayered film on the separating layer, etching the separating layer and separating the multilayered film from the substrate. CONSTITUTION:A thin Al film 11 as a separating layer is formed on a flat glass substrate 12 and a multilayered interference filter having desired characteristics is formed on the film 11 with an ionic bombardment device. The formed interference filter with the substrate is cut to a proper size, the Al film 11 is etched and the cut interference filter is separated from the substrate. Only the interference filter can be taken out as a single filter and the field of application of the filter can be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an interference filter, and in particular to a multilayer interference filter without a substrate.

(Prior Art) As is well known, interference filters are currently widely used as optical members. However, it is generally manufactured by a vapor deposition process, and usually a transparent glass plate is used as a substrate, and vapor deposition is performed on the substrate.

For this reason, the substrate is considered essential, and the problem arises that the manufacture and use of interference filters are restricted depending on the material and shape of the substrate.

(Problems to be Solved by the Invention) This invention can be used to add an interference filter to a substrate that has irregularities or which cannot withstand the processing conditions of conventional interference filter methods.

This makes it possible to add the function of an interference filter to a minute optical member such as an optical fiber, and attempts to eliminate the influence of the substrate from the interference filter.

(Means for Solving the Problem) The method for manufacturing a multilayer interference filter without a substrate of the present invention includes a first step of forming an etched separation layer on a substrate, and a step of forming a multilayer film on the separation layer. It is characterized by comprising two steps, and then a third step of etching the separation layer to separate the substrate and the multilayer film.

More specifically, a first step of forming an aluminum thin film as the separation layer on a flat glass substrate by a conventional method;
The second step is to form a multilayer interference filter having desired characteristics, which is preferably manufactured using an ion bombardment device (for example, see Japanese Patent Application Laid-Open No. 61-37962). The third step is cutting to size, and the fourth step is separating the cut interference filter into a multilayer interference filter and a substrate by etching aluminum.

Furthermore, since the aluminum layer is highly malleable, no stress is accumulated therein during formation of the interference filter, and the interference filter does not deform after separation from the substrate.

The interference filter manufactured in this way has an innovative structure, consisting only of multilayer films and no substrate.

(Example) Hereinafter, this invention will be explained in detail by way of examples.

FIG. 1 shows an example of the above-mentioned ion bombardment device. A substrate 1 held by a rotating substrate holding device in a vacuum chamber is supplied with high-frequency power from a power source 5 via an auxiliary electrode 3 and a matching box 4. Supplied. The constituent substances from the evaporation source 2 are ionized in plasma by high frequency waves, accelerated by a bias electric field generated by the plasma, and collide with and deposit on the surface of the substrate 1. The film quality of the interference filter manufactured using this ion bombardment device has a high density similar to that of a block substance compared to the film quality of the interference filter manufactured using the conventional vacuum evaporation method, and the materials that make up the interference filter are densely packed. It is particularly suitable for this invention because it has the characteristic that it can easily maintain its shape even if the substrate is removed.

In this invention, the substrate 1 has a film thickness of 5000
It uses a glass base on which aluminum is vapor-deposited. FIG. 2 shows a cross-sectional view of the multilayer interference filter manufactured in this way, in which 12 is a glass substrate, 11 is an aluminum film, 9 and 10 are a TiO2 film,
Sin, indicates a membrane.

The table below was used in a trial production to confirm the practicality of the interference filter manufacturing method of the present invention. The materials that make up the interference filter and their film thicknesses are shown.

The theoretical values of the transmission loss characteristics of this interference filter are shown in FIG.

Next, as shown in FIG. 4, this filter is cut into appropriate sizes along with the substrate 12, and the filter layer is separated from the substrate by etching.

In the examples, H, PO4: HNO,: CH
, C00H:H20=16:1:2:1 The Al film was removed at 80°C using an A1 etching solution having a composition of 16:1:2:1, and an interference filter film without damage could be obtained.

The interference film was then cleaned and bonded to the joint of the optical fiber with an adhesive, as shown in FIG.

In the figure, 6 is an optical fiber, 7 is an interference film, and 8 is an optical adhesive. It was confirmed that the bonded multilayer interference filter had performance approximately in accordance with the designed value.

In this embodiment, the interference film was separated and then bonded; however, appropriate changes may be made, such as bonding the film surface together with the substrate and then separating the substrate.

(Effects of the Invention) As described above, the present invention removes the substrate of an optical interference filter, which was conventionally considered common knowledge, and makes it possible to take out only the interference film as a single filter, expanding the range of applications of interference filters. This has the remarkable effect of increasing the degree of freedom in manufacturing optical members.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of the configuration of an example of an ion bombardment device used in manufacturing the filter of this invention, Fig. 2 is a sectional view showing the configuration of the filter in the manufacturing process of the filter of this invention, and Fig. 3 is an interference filter. FIG. 4 is a plan view showing an example of how the filter is cut during the manufacturing process of the filter of the present invention, and FIG. 5 is a method of using the multilayer interference filter of the present invention. The symbols in Figure 1, which is a cross-sectional view showing one example, are 1: Substrate 2: Evaporation source 4: Matching box 6: Optical fiber 8: Optical adhesive 10: SiO, film 12, Glass substrate 3: Auxiliary electrode 5: ffi Source 7: interference film 9: TiO, film 11: Nialuminum film. Figure Figure 1 αυ 1 [+ 120013 (D 14 (D 150
016(D 1711X) 18C019002CI
sword wavelength

Claims (1)

[Claims] 1) forming an etchable separation layer on a substrate;
2) A method for producing a multilayer film interference filter without a substrate, comprising the steps of forming a multilayer film on the separation layer, and then etching the separation layer to separate the substrate and the multilayer film. 2) The separation layer is 3) A method for manufacturing a multilayer interference filter without a substrate according to claim 1, wherein the multilayer interference filter is made of an aluminum thin film. 3) The multilayer interference filter without a substrate is separated from the substrate after forming the multilayer film.