JPH01308918A - Preparation of lattice - Google Patents

Abstract

PURPOSE:To easily and certainly obtain a lattice having an extremely fine lattice pattern by using perpendicularly magnetized film as a magnetic recording medium and writing a magnetic pattern in said film by the use of a magnetic head for perpendicular magnetization. CONSTITUTION:A magnetic disc 1 is constituted of a circular substrate composed of glass and a thin layer like magnetic recording medium 6 is formed to the single surface thereof by the sputtering of a perpendicularly magnetizing substance such as CoCr and a magnetizing direction is set to a predetermined direction in a layer thickness direction. At first, a clock signal 3 is inputted to a magnetic head 2 while the disc 1 is rotated at a low speed and a (1, 0) pattern is written in the peripheral edge part of the disc 1 over one round as a magnetizing pattern due to perpendicular magnetization. Next, when a magnetic colloid fluid 7 having a particle size of 100-200Angstrom is applied to the medium 6 having the magnetizing pattern formed thereto by perpendicular magnetization, the pattern having the same pitch as the magnetizing pattern is formed by the fluid 7. Subsequently, a photocurable transparent resin 8 is applied to the pattern formed by the fluid 7 and irradiated with ultraviolet rays 9 to be cured and the cured resin is released from the disc 1 to obtain a lattice 10.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for making a grid.

[Prior Art] In this specification, a grating pattern includes not only one having a certain periodic structure but also a computer hologram pattern, etc. A grating having such a grating pattern is used, for example, in a linear encoder. It is used in rotary encoders, hologram disks used in hologram scanners, computer holograms, etc.

As a method for producing such a grating, a method using a lithography method and a method using laser light interference are conventionally known.

Fabrication of a grating by lithography is performed as follows. That is, a film of metal such as Cr or AI is formed on a substrate such as glass, and a photoresist is applied thereon. The thus formed photoresist layer is pattern-exposed through a mask with a desired lattice pattern, the photoresist is developed, the metal layer is etched away to form lattice openings, and finally the photoresist layer is exposed to light through a mask with a desired lattice pattern. Remove resist.

Another method uses laser light interference.

Instead of performing pattern exposure using a mask in the lithography method described above, laser light is caused to interfere with the photoresist, and pattern exposure is performed using the interference pattern. Then, the steps of development, etching, and removal of the photoresist are performed in order to obtain a grid.

[Problems to be Solved by the Invention] Among the above methods, in the grating manufacturing method using lithography, pattern exposure is performed using light, so when the pattern becomes finer and the pitch becomes less than 0.3 to 0.4 μm, diffraction occurs. occurs, making accurate pattern exposure impossible.
Therefore, it is not possible to produce a lattice having a finer lattice pattern than a certain degree.

In addition, since the method using laser light interference uses an interference pattern, it is not possible to obtain a grating with a grating pattern other than the pattern that can be generated by interference.
In addition, there are limitations due to the wavelength of light, making it difficult to produce fine pitches.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a novel method for easily and reliably obtaining a grating having a desired grating pattern, particularly an extremely fine grating pattern. The purpose of the present invention is to provide a method for producing a grid.

[Means to solve the problem] The present invention will be explained below.

The present invention is a method for manufacturing a grating having a transmission modulation type grating pattern, and its features are as follows.

That is, first, a desired lattice pattern is written on a magnetic recording medium formed in layers on a substrate using a magnetic head to form a magnetization pattern that follows the lattice pattern. The base body is, for example, a glass substrate. The magnetic recording medium formed in a layered manner on the substrate may be a magnetized film such as Fe2O3, or may be a perpendicularly magnetized film such as CoCr that is uniformly magnetized in a predetermined direction in the thickness direction. Also good.

A magnetic colloidal fluid is then applied onto the magnetic recording medium to produce a pattern of magnetic colloidal fluid corresponding to the magnetization pattern.

A magnetic colloidal fluid is a fine powder of iron oxide dispersed in a surfactant.

The magnetic colloidal fluid used in the present invention is one in which the particle size of the colloid particles is sufficiently small compared to the magnetization pattern, for example, 1
The particle size is from 0.00 to 200.

Subsequently, an unsolidified transparent resin layer is formed on the pattern of the magnetic colloidal fluid, and this resin layer is solidified and peeled off from the magnetic recording medium together with the magnetic colloidal fluid. A grating having a desired transmittance modulation type grating pattern is obtained.

As the transparent resin, a photocurable resin or a thermosetting resin can be used.

Note that, once a magnetization pattern according to a desired lattice pattern is formed on a magnetic recording medium, the same lattice can be obtained one after another by repeating the steps after applying the magnetic colloid fluid.

[Operation] When a lattice pattern is written on a magnetic recording medium with a magnetic head, a magnetization pattern that follows the lattice pattern is formed by the arrangement of magnetic domains magnetized in the in-plane direction or in the perpendicular direction.

A magnetic colloidal fluid 1 made of colloidal particles having a sufficiently smaller particle size than the magnetization pattern is placed on the magnetic recording medium on which the magnetization pattern is formed, for example, 17 times the pitch of the above magnetic domain arrangement.
When a magnetic colloidal fluid with a particle size of about 10 is applied,
Since the magnetic colloidal fluid gathers at the boundaries of the magnetic domains, a pattern of magnetic colloidal fluid having the same pitch as the magnetization pattern is obtained.

Therefore, by copying this pattern onto a transparent resin, a desired grid can be obtained.

When writing a lattice pattern on a magnetic recording medium with a magnetic head, if a perpendicularly magnetized film is used as the magnetic recording medium and the film thickness is uniformly magnetized in a predetermined direction, and a magnetic head for perpendicular magnetization is used, the maximum recording density is approximately 250Kbits/1n
Possible up to ch. That is, 1 bitlo, 1μ
m, and the magnetic domains can be reversed with a minimum pitch of 0.1 μm.

Therefore, a perpendicular magnetization pattern with a minimum pitch of 0.1 μm can be written and formed using a magnetic head.

In addition, when using a magnetized film such as Fe2O3 as a magnetic recording medium and magnetizing in the in-plane direction, it is not possible to obtain a high recording density in the diameter when a perpendicular magnetized film is used, but it is extremely easy to create a magnetized pattern, especially It is extremely effective for producing gratings with a pitch of 1 μm or more.

[Examples] Two specific examples will be described below with reference to the drawings.

Each of the examples is an example of manufacturing a disc-shaped grating used in a rotary encoder.

In FIG. 1, reference numeral 1 indicates a magnetic disk. This magnetic disk 1 has a circular substrate such as glass as a base, and a thin layered magnetic recording medium is formed on one side of the substrate by sputtering a perpendicularly magnetized substance such as CoCr, and the direction of magnetization is set in a predetermined direction in the layer thickness direction. They are aligned and can be rotated around a rotation axis AX by a rotation means (not shown). The layer thickness of a magnetic recording medium is approximately several thousand layers.

Reference numeral 2 indicates a magnetic head for perpendicular magnetization.

While rotating the magnetic disk 1 at a constant speed in the direction of the arrow, a clock signal 3 is input to the magnetic head 2, and a 1,0 pattern is set as a magnetization pattern 4 by perpendicular magnetization, and a 1 is applied to the periphery of the magnetic disk 1.
Write and record over the course of the week. Of course, this magnetization pattern 4 is not a pattern that can be seen with the naked eye.

The second figure schematically shows the magnetization pattern written and recorded in this way. The left-right direction in the figure corresponds to the rotation direction of the magnetic disk.

In FIG. 2, reference numeral 5 indicates a circular substrate of a magnetic disk, and reference numeral 6 indicates a circular substrate of a magnetic disk.
indicates a magnetic recording medium formed in a thin layer.

Small arrows on the magnetic recording medium 6 indicate the direction of magnetization. That is, as a result of writing by the magnetic head 2 for perpendicular magnetization, an arrangement of minute magnetic domains whose magnetization directions are reversed in the thickness direction of the magnetic recording medium 6 according to clocks 1 and 0, that is, a magnetization pattern due to perpendicular magnetization. is formed. The pitch of the magnetic domain arrangement in this magnetization pattern is 0.1 to 0.2 μm. In addition, in the direction perpendicular to the drawing in FIG. 2, that is, in the radial direction of the magnetic disk, the magnetic states shown in FIG. 2 are present for a finite distance.

Next, when a magnetic colloidal fluid 7 with a particle size of 100 to 200 particles is applied onto the magnetic recording medium 6 on which a magnetization pattern is formed by perpendicular magnetization as described above, the magnetic colloidal fluid 7 becomes magnetic as shown in FIG. Since the particles gather at the boundaries of the magnetic domains forming the magnetization pattern formed on the recording medium 6, a pattern having the same pitch as the magnetization pattern is formed by the magnetic colloid fluid 7.

Subsequently, as shown in FIG. 4, a photocurable transparent resin 8 is applied onto the pattern formed by the magnetic colloidal fluid 7, and is cured by irradiating it with ultraviolet light (W9). Then, when the cured transparent resin 8 is peeled off from the magnetic disk 1,
As shown in FIG. 5, a grid 10 is obtained in which a pattern of magnetic colloidal fluid 7 is embedded on one side of the cured transparent resin. In this grating 10, a magnetization pattern due to perpendicular magnetization is copied as a pattern of the magnetic colloidal fluid 7,
Therefore, it is a transmission modulation type grating with the same pitch as the magnetization pattern. By repeating the process shown in FIGS. 3 to 5, the same grid can be obtained one after another.

FIG. 6 shows another embodiment.

In FIG. 6, reference numeral IA indicates a magnetic disk. This magnetic disk IA has a circular substrate made of glass or the like as a base, and has a thin layered magnetic recording medium formed on one side by coating Fe2e3, etc., and is rotated around a rotation axis AX by a rotation means (not shown). It has become possible. The layer thickness of a magnetic recording medium is approximately several thousand layers.

Reference numeral 2A indicates a magnetic head.

While rotating the magnetic disk IA at a constant speed in the direction of the arrow, a clock signal 3 is input to two magnetic heads, and a 1.0 pattern is set as an in-plane magnetization pattern 4A to the periphery of the magnetic disk IA for one rotation. Write and record.

FIG. 7 schematically shows the magnetization pattern written and recorded in this way. In the left and right direction of the figure, magnetic disk IA
It corresponds to the direction of rotation.

In FIG. 7, reference numeral 5A indicates a circular substrate of a magnetic disk, and reference numeral 6A indicates a magnetic recording medium formed in a thin layer.

Small arrows in the magnetic recording medium 6A indicate the direction of magnetization. That is, as a result of writing by the magnetic head 2A, an array of magnetic domains whose in-plane magnetization directions are reversed in accordance with clocks 1 and 0 is formed. The pitch of this magnetic domain arrangement is 1 to several μm.

In addition, in the direction perpendicular to the drawing in FIG. 7, that is, in the radial direction of the magnetic disk, the magnetic state shown in FIG. 7 continues for a finite length.

Next, when a magnetic colloidal fluid 7 with a particle size of 100 to 200 particles is applied onto the magnetic recording medium 6A on which a magnetization pattern is formed by in-plane magnetization as described above, the magnetic colloidal fluid 7 is Since the magnetic colloidal fluid 7 gathers at the boundaries of the magnetic domains forming the magnetization pattern formed on the magnetic recording medium 6A, a pattern having the same pitch as the magnetization pattern is formed by the magnetic colloid fluid 7.

Thereafter, as in the case of the previously described embodiment, a photocurable transparent resin is applied onto the pattern formed by the magnetic colloidal fluid 7, and is cured by irradiating it with ultraviolet rays to form the cured transparent resin. By peeling off the magnetic disk IA from the magnetic disk IA, a grid in which a pattern of the magnetic colloidal fluid 7 is embedded on one side of the cured transparent resin is obtained. This grid is
A magnetization pattern due to in-plane magnetization is copied as the pattern of the magnetic colloidal fluid 7, and therefore, it is a transmission modulation type grating having the same pitch as the magnetization pattern. By repeating the process from applying the magnetic colloid fluid to peeling off the cured transparent resin, the same grid can be obtained one after another.

[Effects of the Invention] As described above, according to the present invention, a novel method for producing a lattice can be provided.

This method is configured as described above.

A transmission modulation type grating can be obtained easily, reliably, and at low cost. In particular, by using a perpendicularly magnetized film as a magnetic recording medium and writing a magnetic pattern thereon with a perpendicularly magnetized magnetic head, a lattice pattern with a minimum pitch of 0.1 μm can be realized. This is
This is barely possible by drawing a pattern using lines, but it is difficult to create the mask necessary for this with X-ray drawing, and it is difficult to achieve this in practice. However, according to the present invention, it is possible to easily produce a grating having such a fine grating pattern as described above.

In addition, when forming a magnetization pattern by in-plane magnetization,
In particular, it makes it extremely easy to produce a grating having a pitch of 1 μm or more.

Furthermore, in the present invention, since the lattice pattern is basically written on the magnetic recording medium by a magnetic head, it is easy to increase the area, and furthermore, various lattice patterns can be easily realized. Therefore, it is possible to create not only a grating for a rotary encoder as in the embodiment, but also a linear grating for a linear encoder, or an amplitude hologram having a computer hologram pattern by writing a hologram pattern calculated by a computer with a magnetic head. It can be easily produced as a lattice.

In the examples, a photocurable resin was used as the transparent resin, but it goes without saying that a thermosetting resin may be used instead and cured by heating. moreover,
In the case of the embodiment, a circular grating pattern having a plurality of tracks can be easily realized by writing different signals using a plurality of magnetic heads.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the perpendicular writing of a magnetization pattern onto a perpendicularly magnetized circular magnetic recording medium, and FIG. 2 is a diagram for explaining the state of the magnetization pattern written as described above. , Fig. 3 is a diagram for explaining pattern formation using magnetic colloidal fluid, Fig. 4 is a diagram for explaining curing of transparent resin, and Fig. 5 is a diagram for explaining the completed lattice. , FIG. 6 is a diagram for explaining writing of a magnetization pattern by in-plane magnetization onto a magnetic recording medium, FIG. 7 is a diagram for explaining the state of a magnetization pattern by in-plane magnetization, and FIG. 8 is a diagram for explaining the state of a magnetization pattern by in-plane magnetization. FIG. 2 is a diagram for explaining pattern formation by a magnetic colloid fluid according to a magnetization pattern by one-plane magnetization. 100. magnetic disk, 200. magnetic head for perpendicular magnetization,
310. clock signal, 480. Perpendicular magnetization pattern, 5
10. A circular substrate as a base, 6°0. perpendicular magnetization medium,
700. Magnetic colloidal fluid, 801. Transparent photocurable resin, 10. , , lattice IA'% a factor
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Claims (1)

[Claims] A method for producing a grating having a transmittance-modulated grating pattern, the method comprising: writing a desired grating pattern onto a magnetic recording medium formed in layers on a substrate using a magnetic head; After forming a magnetization pattern according to the pattern, a magnetic colloidal fluid whose colloid particle size is sufficiently smaller than that of the magnetization pattern is applied onto the magnetic recording medium to form a magnetic colloidal fluid corresponding to the magnetization pattern. generating a pattern, then laminating an unsolidified transparent resin layer on the pattern of magnetic colloidal fluid, then solidifying this resin layer and peeling it together with the magnetic colloidal fluid from the magnetic recording medium; A lattice fabrication method characterized by: