JPS60170802A - Adjusting method of relief shape of relief type diffraction grating - Google Patents

Abstract

PURPOSE:To eliminate unevenness of diffraction efficiency by detecting diffracted light obtained by irradiating the relief surface of the relief type diffraction grating with laser light, and thus forming a thin film layer on the relief surface while monitoring the relief shape. CONSTITUTION:The diffraction grating 3 is arranged with the relief surface 4 down in a vacuum tank which is evacuated by a vacuum discharge system 1 to a proper degree of vacuum, and a vapor-deposition source 5 is arranged under it to form a thin film layer on the relief surface 4 by vapor-depositing metal. The laser light 7 from a laser light source 6 in the tank through an optical introduction system 8 provided on the external wall of the vacuum tank 2 and reflected by a mirror 9 to illuminate the relief surface 4 of the diffraction grating 3 and the resulting diffracted light 10 is detected by a detector 11, which is connected to an external measurement system 12 to take a measurement of the diffraction efficiency. Thus, while the diffraction efficiency is monitored, a vapor-deposition shutter 13 is opened and closed to left and right as shown by an arrow to control the formation of the thin film.

Description

[Detailed description of the invention] The present invention relates to a method that allows adjustment of a desired shape to a desired shape.

Conventionally, diffraction gratings have been used for many purposes as optical components and electronic components, and are required to have high and uniform diffraction efficiency.

Diffraction gratings are generally manufactured by cutting a suitable base material or optically by three-beam interferometry.
Makuichi l1-1rb1lZIl[''1+4hi□==□, a
Although it is very important to obtain 61+m+ and to make the diffraction efficiency uniform, it often has the drawback that the diffraction efficiency is partially non-uniform, and the thin film j Even if the film thickness of - is controlled, it is difficult to select conditions for obtaining preferable diffraction efficiency.

The present invention solves the drawbacks of the above-mentioned prior art, and includes:
The present invention is characterized by forming a thin film layer on the relief surface while monitoring the relief shape by irradiating the relief surface of the relief type diffraction grating with a laser beam and detecting the diffracted light obtained. Relief type diffraction grating 9 Relating to a method for adjusting the shape of the first face.

The method for forming the thin film layer in the present invention may be any method that can form a safmicron thin film, such as vapor deposition, sputtering, ion plating, CVDS casting, or spray coating, and the material for forming the thin film may also be used. Any method may be used as long as these thin film forming force methods can be used.

In addition, the method for detecting (monitoring) diffracted light in the present invention is 0
A method may be used in which the second-order light (transmitted light), seventh-order light, or diffracted light of second or higher order light is detected individually, or a method may be used in which a plurality of these lights are detected and the correlation between them is determined. In addition, if the material of the oil film to be formed is optically transparent, it is possible to detect (monitor) the 0th order light (transmitted light) and the 41i light, and r'
4 If the In material is light reflective, the reflected 0th order light and diffracted light can be monitored.

Figure 1 shows the cross-sectional shape of a relief type diffraction grating obtained by the method of the present invention. As an example, it is an explanatory diagram of the equipment used to show a method for forming a light-reflecting substance using a vacuum evaporation equipment and monitoring reflected diffraction light, and shows a vacuum evacuation system/more appropriate vacuum. A diffraction grating 3 is placed in a vacuum chamber λ which is evacuated to a temperature of The structure is such that a thin film layer is formed. Reference numeral 6 represents a laser light source, and laser light 7 is introduced into the chamber from an optical introduction system g provided on the outer wall of the vacuum chamber, reflected by a mirror, and then exposed to a diffraction grating. The diffracted light 10 obtained is detected by a detector //, and the diffraction efficiency is determined by connecting it to an external measurement system /2. While monitoring the diffraction efficiency, the deposition shutter 73 is opened and closed in the directions indicated by the arrows, that is, in the left and right directions to control the formation of the thin film.

Figure 3 shows an example of a method in which a diffraction grating is formed on the surface of a transparent base material, and a light-transmitting material is formed by vacuum deposition. The transmitted diffracted light 10 is diffracted by q and passes through the detector //
This figure shows how the image is detected, and the rest is the same as that shown in FIG. 2.

FIG. 9 shows a case where the diffraction efficiency is monitored not at one point as in FIGS. 2 and 3, but at various points. In Figure 9, the laser beam 7 is mirrored /9
After reflecting the beams a and b by the mirror 9, the diffraction grating 3 (2) is irradiated, and the concave mirror 3 detects the light 10 by the detector //, and the measurement system 2 Mirror 1llb and mirror /lI in FIG.
Dot-dash line σ from b to detector l/ Show mirror/<I! By changing the angle of b, the location other than the diffraction grating σ) is shown to be monitored. /6 in Figure 7 is the opening /7
The size of the aperture /7 is 0.0 mm of the area of the diffraction grating. It is recommended to set the value to about /~/ times and move it according to the monitoring results.

According to the above-described method of the present invention, a thin film layer can be formed while monitoring the diffraction efficiency (σ), so it is possible to eliminate non-uniformity in diffraction efficiency and to obtain diffraction efficiency over the entire surface. EJ becomes Noh.

Therefore, since the diffraction grating obtained by the method of the present invention has a high viscosity, using this as a prototype...
・j -λ ゛--q-bow Sner 1, M 5l' 11111 + LE 111 KI-VL size Using electron beam or ultraviolet curing resin (make a two-strand mold, and use such a mold It can be used for duplication by imprinting on thermoplastic resin.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a diffraction grating obtained by the method of the present invention,
FIGS. 2 to 3 are explanatory diagrams of an apparatus for illustrating the method of the present invention. 3... Diffraction grating... Vapor deposition source 6... Laser light source //l...
・Φ・-・Mirror/Otsu-・1 fist 1 groan-Deposition mask Patent applicant Dai Nippon Printing Co., Ltd. Representative Patent attorney Atsumi Konishi

Claims (1)

[Claims] While monitoring the relief shape by detecting the diffracted light obtained by irradiating the relief surface of the relief-type diffraction grating with a laser beam, the relief surface (relie, characterized by forming one thin film layer) type diffraction is performed. How to adjust the relief shape of the lattice.