JP2012014074A - Spatial light modulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spatial light modulator that operates at high speed and is capable of obtaining a sufficient intensity ratio of modulation.SOLUTION: A spatial light modulator modulates spatial intensity of reflected or transmitted light by reflecting or transmitting incident light and comprises: magnetic thin lines 11 respectively made of a vertical magnetization film; a magnetization mechanism 12 for partially changing the magnetization status of the magnetic thin lines 11; and a current supply mechanism for supplying an unidirectional current into the magnetic thin lines 11 to transmit the magnetization status changed by the magnetization mechanism 12 within the magnetic thin lines 11.

Description

  The present invention relates to a spatial light modulator, and is suitable for use in a hologram display device and a hologram light recording device.

  A hologram display device, which is one of three-dimensional image display devices, is characterized in that it can display natural three-dimensional images without using special glasses or the like.

In the hologram display device, since light interference is used, in order to freely manipulate a display image, it is necessary to modulate the light intensity with a size equal to or smaller than the light wavelength.
Further, in order to display a moving image on a hologram display device, a large number of light modulation elements that operate at high speed are required.

As a condition satisfying such a condition, for example, a spatial light modulator (for example, see Patent Document 1) using spin injection magnetization reversal capable of reversing the magnetization direction of a fine magnetic material at high speed. ,Proposed.
A spatial light modulator (see, for example, Patent Document 2) using domain wall motion of an in-plane magnetization film having magnetization in the in-plane direction has also been proposed.

JP 2010-60668 A JP 2010-20114 A

However, in the method in which the spatial light modulator is configured by arranging a large number of fine light modulation elements and each element is operated, the element area is small and the electrode for passing a current through the element has a large area. There is a problem that it is difficult to obtain a sufficient modulation intensity ratio of light because it is exclusively used.
In addition, there is a drawback in that power consumption increases when current is simultaneously supplied to a plurality of elements.

  In order to solve the above-described problems, the present invention provides a spatial light modulator that operates at high speed and can obtain a sufficient modulation intensity ratio.

The spatial light modulator of the present invention is a spatial light modulator that modulates the spatial intensity of reflected or transmitted light by reflecting or transmitting incident light.
Then, a magnetic thin wire constituted by a perpendicular magnetic film, a magnetization mechanism for changing the magnetization state of a part of the magnetic thin wire, and a magnetization changed by the magnetization mechanism by supplying a current in one direction in the magnetic thin wire. And a current supply mechanism for propagating the state in the magnetic thin wire.

According to the configuration of the spatial light modulator of the present invention described above, the magnetization mechanism that changes the magnetization state of a part of the magnetic thin wire, and the magnetization changed by the magnetization mechanism by supplying a unidirectional current to the magnetic thin wire. And a current supply mechanism for propagating the state in the magnetic thin wire.
As a result, the magnetization state changed by the magnetization mechanism can be propagated through the magnetic thin wire by the current supplied by the current supply mechanism, and an arbitrary magnetization pattern can be formed on the magnetic thin wire. Light can be modulated using the magnetization state of each region.
The operation of changing the magnetization state of the magnetic thin wire by the magnetization mechanism and the operation of propagating the magnetization state by the current supply mechanism in the magnetic thin wire can be operated at relatively high speeds.
Furthermore, since light can be modulated in the magnetization state of each region of the continuous magnetic thin wire, the region is compared with a spatial light modulator having a configuration in which individual light modulation elements are formed for each region. It is possible to reduce the gap between the electrodes, reduce the number of electrodes, and reduce the area occupied by the electrodes. Thereby, the area ratio of the part which contributes to modulation can be improved.

According to the above-described present invention, it is possible to improve the area ratio of the portion that contributes to the modulation on the light irradiation surface, and to efficiently modulate the light intensity.
Further, since the number of electrodes can be reduced as compared with a spatial light modulator having a configuration in which individual light modulation elements are formed, the price of the spatial light modulator can be reduced correspondingly.
be able to.
Furthermore, compared with a spatial light modulator having a configuration in which individual light modulation elements are formed, the gap between the regions can be reduced, so the number of regions can be increased by reducing the size of each region, and the resolution can be increased. It can also be improved.

According to the present invention, it is possible to form various light modulation patterns by forming a magnetization pattern in a magnetic thin wire with a relatively high speed operation.
Therefore, it is possible to realize a stereoscopic image display device capable of displaying a high-definition moving image and a hologram optical recording device capable of high-speed and high-speed operation using the spatial light modulator of the present invention.

It is a figure (perspective view) which shows typically the basic component of the spatial light modulator of the present invention. AE is a figure explaining the operation method of the magnetization of the operation | movement principle of the spatial light modulator of this invention. It is a schematic block diagram (plan view) of the first embodiment of the spatial light modulator of the present invention. It is a schematic block diagram (plan view) of the second embodiment of the spatial light modulator of the present invention. It is a schematic block diagram (perspective view) of 2nd Embodiment of the spatial light modulator of this invention. It is a schematic block diagram (plan view) of the third embodiment of the spatial light modulator of the present invention. It is sectional drawing of one form of the magnetization mechanism of the spatial light modulator of FIG. It is a top view which shows the form of the magnetic body thin wire | line of AD modification. AC is a figure which shows the form of the electric current waveform sent through the magnetic body thin wire | line of each modification of FIG. AC is a figure which shows the structure of the comparison with respect to 4th Embodiment of the spatial light modulator of this invention. A to C are schematic configuration diagrams of a fourth embodiment of the spatial light modulator of the present invention. A to C are schematic configuration diagrams of a fourth embodiment of the spatial light modulator of the present invention. A to C are manufacturing process diagrams showing a manufacturing method of the fifth embodiment of the spatial light modulator of the present invention. A to C are manufacturing process diagrams showing a manufacturing method of the fifth embodiment of the spatial light modulator of the present invention. A to C are manufacturing process diagrams showing a manufacturing method of the fifth embodiment of the spatial light modulator of the present invention. A to C are manufacturing process diagrams showing a manufacturing method of the fifth embodiment of the spatial light modulator of the present invention. A to C are manufacturing process diagrams showing a manufacturing method of the fifth embodiment of the spatial light modulator of the present invention. A to C are manufacturing process diagrams showing a manufacturing method of the fifth embodiment of the spatial light modulator of the present invention. A to D are manufacturing process diagrams showing a manufacturing method of the fifth embodiment of the spatial light modulator of the present invention. It is a manufacturing process figure which shows the manufacturing method of 5th Embodiment of the spatial light modulator of this invention. In the structure of 5th Embodiment of the spatial light modulator of this invention, it is a partial top view of the structure which has arrange | positioned many element groups regularly. It is a figure which shows one form of the combination of the exciting current sent through the conductor wire of the magnetization mechanism at the time of recording operation, and the current sent through each magnetic thin film wire. It is a figure which shows one form of a structure of the optical system at the time of using a spatial light modulator. It is a figure which shows the other form of a structure of the optical system at the time of using a spatial light modulator. A and B are diagrams showing one mode of a modulation direction when using the spatial light modulator of the present invention. A, B It is a figure which shows the other form of the modulation direction at the time of using the spatial light modulator of this invention.

Hereinafter, the best mode for carrying out the invention (hereinafter referred to as an embodiment) will be described.
The description will be given in the following order.
1. 1. Outline of the present invention First Embodiment 3. FIG. Second embodiment 4. Third embodiment 5. Modification 6 Fourth embodiment 7. Fifth embodiment Experimental Example 9. 9. Writing method to spatial light modulator 10. Optical system when using spatial light modulator Modulation method when using a spatial light modulator

<1. Summary of the present invention>
First, prior to description of specific embodiments of the present invention, an outline of the present invention will be described.
In order to achieve the above-described object, the inventors have repeatedly studied.
As a result, a perpendicular magnetization film is formed on a plane as striped magnetic thin wires, and an electrode is provided for passing a current through a part of the magnetic thin wire and a magnetization mechanism for changing the magnetization state of a part of the thin wire. The inventors have found that the magnetization state generated by the magnetization mechanism is moved within the magnetic thin wire.
As a result, when an arbitrary magnetization state is formed in the magnetic thin wire, for example, linearly polarized light is incident on the magnetic thin wire, and the reflected light is passed through the polarizer, the magnetization state is reflected by the magneto-optical effect. A modulation of the reflection intensity can be obtained.
If the magnetization modulation width is equal to or sufficiently small as the wavelength of the irradiation light, the light interference can be controlled by the magnetization state, and function as a spatial light modulation element suitable for hologram display and the like. Can do.

In the present invention, a spatial light modulator is provided that modulates the spatial intensity of reflected or transmitted light by arranging magnetic thin wires formed of perpendicularly magnetized films and reflecting or transmitting incident light.
Further, a magnetic mechanism for changing the magnetization state of a part of the magnetic thin wire by at least one of a magnetic field, heat, or injection of polarized spin is provided for the magnetic thin wire.
Furthermore, a current supply mechanism is provided for supplying a current in one direction in the magnetic thin wire to propagate the magnetization state changed by the magnetization mechanism in the magnetic thin wire.

Specific structures of the magnetization mechanism include those that apply a current magnetic field of a conductor, those that raise the temperature of the magnetic material by a heat source, and change the magnetic properties, and that occur when polarized electrons are injected into the magnetic material. The thing by a spin transfer torque is mentioned. A plurality of these mechanisms may be combined.
Specific configurations of the current supply mechanism include an electrode provided at the end of the magnetic thin wire, a transistor that is electrically connected to one end of the magnetic thin wire, and controls on / off of the current flowing in the magnetic thin wire, etc. Is mentioned.

In the spatial light modulator of the present invention, as a method of moving the magnetization state generated in the magnetic thin wire by the magnetization mechanism, for example, it is performed by a domain wall driving action such as spin torque generated when a current flows through the magnetic body. Is effective.
Such a method is disclosed in the literature (Kab-Jin Kim et al, IEEE Trans. Magn. Vol. 45, No. 10, pp. 3773 (2009)).
That is, by flowing a current in one direction in the magnetic thin wire, the magnetization state generated in the magnetic thin wire can be propagated in the magnetic thin wire.
As a result, an arbitrary magnetic structure can be formed in the magnetic thin wire, and the space of reflected light or transmitted light can be obtained by the magneto-optical action of the magnetic substance or the indirect optical effect by the magnetic field generated by the magnetic substance. Intensity can be modulated.

If the magnetic properties of the magnetic material constituting the magnetic thin wire are appropriately selected, a domain wall is generated at the boundary where the magnetization state (magnetization direction; upward and downward) of the magnetic thin wire is changed.
In many cases, the domain wall moves in the direction opposite to the current direction due to a current magnetic field, a temperature rise, a spin transfer torque, or the like generated when a current is passed through the magnetic thin wire.

  Electrodes for passing a current through the magnetic thin wire may be installed at both ends of the magnetic thin wire, or a plurality of electrodes may be installed at appropriate positions on the magnetic thin wire.

As a magnetic material used for the magnetic thin wire constituting the spatial light modulator of the present invention, a perpendicular magnetization film having appropriate perpendicular magnetic anisotropy is suitable. In particular, a material having a large magneto-optical effect is desirable.
For example, an alternating laminated film such as Co / Pt, Co / Pd, Co / Ni, or Fe / Ni, or an alloy film such as GdFeCo, TbFeCo, FePt, MnBi, MnGa, or PtMnSb can be used.
In addition, a composite film, a laminated film, or an alloy film in which any of the above materials is arbitrarily combined and an oxide magnetic material such as gadolinium / gallium / garnet oxide can be used in combination.

The magnetic material used for the magnetic thin wire may be a single magnetic material, or by laminating a plurality of magnetic materials via nonmagnetic metal layers such as Cr, Cu, Ru, Re, Os, etc. Magnetization may be magnetically interacted with an appropriate strength.
Also, an oxide such as SiO ₂ , Al ₂ O ₃ , MgO, a nitride such as Si ₃ N ₄ , AlN, or an organic material such as a resin is formed on these magnetic materials with an appropriate thickness. Thus, it is more effective to reinforce the magneto-optical effect.

The coercive force of the magnetic material constituting the magnetic thin wire should be large in order to maintain the magnetization state for a certain period of time. However, in order to operate at a low current, the coercive force is preferably small. It is preferable to set it to an appropriate value that can achieve both. Therefore, the material and dimensions of the magnetic thin wire are set.
In order to make the domain wall easy to move, an appropriate external magnetic field may be applied at the same time as a current is passed through the magnetic thin wire.

According to the configuration of the spatial light modulator of the present invention, light is irradiated by arranging a large number of magnetic thin wires without using a member that lowers the reflectance of light like a transparent electrode. It is possible to cover the region to be covered with the magnetic thin wire with a wide area ratio.
Therefore, the light modulation efficiency can be increased.

In particular, since light can be modulated in the magnetization state of each region of the continuous magnetic thin wire, compared with a spatial light modulator having a configuration in which individual light modulation elements are formed for each region, Have the following advantages.
(1) Since the gap between regions can be reduced, the area ratio of the portion contributing to modulation can be improved, and the resolution can be improved by increasing the number of regions by reducing the size of each region. It is also possible to do.
(2) The number of electrodes required for driving the spatial light modulator can be reduced, and the area occupied by the electrodes can be reduced. This also improves the area ratio of the portion contributing to modulation. In addition, the number of electrodes can be reduced, and the price of the spatial light modulator can be reduced accordingly.

  The operation of changing the magnetization state of the magnetic thin wire by the magnetization mechanism and the operation of propagating the magnetization state by the current supply mechanism in the magnetic thin wire can be operated at relatively high speeds.

  Therefore, by using the spatial light modulator of the present invention, it is possible to realize a stereoscopic image display device capable of displaying a high-definition moving image and a hologram optical recording device capable of high-speed operation at high density. . Then, a smooth moving image hologram can be displayed by the hologram optical recording apparatus capable of high-speed operation.

  The spatial light modulator of the present invention may be used by reflecting light, transmitting light, or using both at the same time. Since is generally a metal, it is efficient to use reflected light.

Alternatively, a structure in which a plurality of magnetic thin wire layers are stacked may be configured such that light is transmitted from the gap between the upper magnetic fine wires to the lower magnetic fine wire through the transparent insulating layer.
By adopting such a configuration, the area ratio of the magnetic thin wire can be further increased and a higher light reflectance can be realized as compared with a configuration in which the magnetic thin wire has only one layer.

As a method of modulating light using the spatial light modulator of the present invention, there is a method of using a magneto-optical effect due to magnetization of a magnetic thin wire.
In addition, instead of using the direct magneto-optical effect, the magnetic colloid and magnetic fluid are aggregated using the leakage magnetic field generated around the magnetic domain of the magnetic thin wire, and the light reflection intensity or the light transmission There is also a method of changing the intensity.

  In addition, if the portion where the magnetization of the end of the magnetic thin wire or the electrode does not move is covered with an aperture such as a light blocking object, unnecessary light reflection can be suppressed, and the light modulation rate can be increased. More effective.

In addition, forming a microlens group on the surface of the magnetic thin wire is also effective in reducing light irradiated to other than the magnetic thin wire.
The microlens group may modulate the thickness of the transparent oxide or organic substance by a technique such as photolithography.
Also, using the steps that occur during the formation of magnetic thin wires, the film forming conditions are set so that a transparent insulating film such as ceramics or resin is thick on the magnetic thin wires and thin otherwise. Then, the formed transparent insulating film functions as a lens. This method is simpler and more effective.

The shape of the magnetic thin wire used in the spatial light modulator of the present invention may be a straight line, a curve, or a three-dimensional structure. Moreover, a smooth curved shape may be used, and the shape, film thickness, and side surface position may be changed periodically.
With a magnetic thin wire having a smooth curved shape, the domain wall moves smoothly when a current is passed through the magnetic thin wire, and the operating current can be reduced.
Note that a plurality of striped magnetic thin wires may be arranged in parallel, or one continuous magnetic thin wire may be bent and arranged in parallel.

In a magnetic thin wire whose shape or film thickness is periodically changed, a part in which the domain wall is easy to move and a part in which the domain wall is difficult to move are generated due to the change in shape or film thickness.
Since the domain wall has a portion that is difficult to move, the operating current increases. However, since the domain wall stops at a predetermined position, the position of the domain wall can be easily controlled even with a long magnetic thin wire.

An integrated circuit equipped with a transistor is provided to pass a current through the magnetic thin wire and operate the magnetization mechanism of the magnetic thin wire, and the magnetic thin wire and the magnetization mechanism of the spatial light modulator are formed on the integrated circuit. It is preferable to increase the degree of integration.
Further, it is more preferable to incorporate a logic circuit for calculating and storing the magnetization pattern formed on the magnetic thin wire into this integrated circuit.

As described above, the magnetic thin wire of the perpendicular light film is used for the magnetic thin wire of the spatial light modulator of the present invention. Therefore, the degree of freedom of the shape of the magnetic thin wire is high and preferable.
However, by using a perpendicular magnetization film, the coercive force of the magnetic material tends to increase and it is difficult to reverse magnetization.
Therefore, it is preferable to arrange a magnetic material that provides in-plane magnetization in the in-plane direction in a part of the magnetic thin wire, particularly in the vicinity of the magnetization mechanism, and to change the magnetization of the magnetic thin wire in this portion to in-plane magnetization. Thereby, the direction of magnetization becomes easy to move, and the current required for the magnetization reversal of the magnetic thin wire can be lowered.

Two electrodes may be provided for each magnetic thin wire, but one end of a plurality of magnetic thin wires is electrically connected in common, and the other electrode of each magnetic thin wire is connected. A transistor for applying a current may be connected to the terminal.
In this configuration, when operating the spatial light modulator, the n number of magnetic thin wire transistors whose magnetization is desired to be moved are set to a high potential, and n + 1 or more of the other magnetic thin wires are set. Is preferably set to a low potential. With this setting, since a larger current flows than the other magnetic thin wires through the magnetic thin wire whose magnetization is to be moved, the magnetization state of only the magnetic thin wire having an electrode set at a high potential can be driven. As the number of electrodes set to a low potential is larger, the current flowing other than the target magnetic thin wire can be reduced, so that unnecessary current does not flow through the magnetic thin wire.

Here, basic components of the spatial light modulator of the present invention are schematically shown in the perspective view of FIG.
Electrodes 2 for flowing current to the magnetic body 1 are connected to both ends of the stripe-shaped magnetic body 1. Although not shown, one of the two electrodes 2 at both ends of the magnetic body 1 is connected to a voltage supply unit (power source or the like), and the other electrode is connected to a transistor or the like of the integrated circuit. Yes.
Further, a conductor wire 3 insulated from the magnetic body 1 is provided above the magnetic body 1, and electrodes 4 are connected to both ends of the conductor wire 3. The electrode 4 for the conductor wire 3 is also connected to the transistor of the integrated circuit, like the electrode 2 for the magnetic body 1.
By integrating a large number of magnetic bodies 1 shown in FIG. 1, the spatial light modulator of the present invention can be configured.

Next, taking as an example the case where the magnetic body 1 is formed of a perpendicularly magnetized film, a magnetization operation method which is the basis of the operation principle of the spatial light modulator of the present invention will be described with reference to FIGS. 2A to 2E. To do. 2A to 2E show the longitudinal section of the stripe-shaped magnetic body 1 shown in FIG. 1, where the left and right are the longitudinal direction of the magnetic body 1, and the top and bottom are the thickness direction of the magnetic body 1. Further, the direction of the magnetization 5 of the magnetic body 1 is schematically shown.
A magnetic field is generated by a current flowing through the conductor wire 3. The conductor wire 3 may be composed only of a nonmagnetic metal material, but in order to generate a magnetic field more efficiently, it is preferable to attach a soft magnetic material to an appropriate portion of the conductor.
First, FIG. 2A shows an initial state in which all the magnetizations 5 of the magnetic body 1 are upward. In actual operation, the magnetization in the initial state can be operated in an arbitrary state.
Next, as shown in FIG. 2B, when the current I1 flowing through the conductor wire 3 is set to flow in the direction from the front side to the back side of the paper, the magnetic field H generated by the current turns clockwise. The magnetization 5 of the lower magnetic body 1 changes, and the right side of the conductor wire 3 faces downward and the left side faces upward. And the domain wall 6 is produced | generated in the boundary of magnetization 5 direction of a magnetic body.
Furthermore, as shown in FIG. 2C, when the current I1 continues to flow through the conductor wire 3 in the same direction, and the leftward current I2 flows through the magnetic body 1, the region in which the magnetization 5 is downward expands to the right, and the domain wall 6 moves to the right.
Here, as shown in FIG. 2D, when the direction of the current I1 flowing through the conductor wire 3 is changed from the back side to the near side, the magnetic field H also reverses counterclockwise. The magnetization 5 of the magnetic body 1 changes, and the right side of the conductor wire 3 faces upward and the left side faces downward. As a result, a new domain wall 7 is generated.
Furthermore, as shown in FIG. 2E, when the current I1 continues to flow through the conductor wire 3 in the same direction, and the leftward current I2 flows through the magnetic body 1, both the domain walls 6 and 7 move to the right.

Thus, if the current I2 is passed through the magnetic body 1 while changing the direction of the current I1 flowing through the conductor wire 3 corresponding to the pattern of the magnetization 5 to be formed, the stability of the magnetization 5 of the magnetic body 1 is not impaired. As long as an arbitrary pattern can be formed.
As described above, one magnetic thin wire of the spatial light modulator of the present invention can be operated.
The current I2 flowing through the magnetic body 1 may be a continuous current, an intermittent current, or a modulated intensity.

<2. First Embodiment>
FIG. 3 shows a schematic configuration diagram (plan view) of the first embodiment of the spatial light modulator of the present invention.
In the present embodiment, four striped magnetic thin wires 11 are provided.
And the common conductor wire 12 used as a magnetization mechanism is provided in the left end part of each magnetic thin wire | line 11, and the spatial light modulator is comprised.
In addition, although not shown in the drawing, a transistor or the like for flowing a current through the magnetic thin wire 11 is connected to the right end portion of each magnetic thin wire 11.

The magnetic thin wire 11 is formed using a perpendicular magnetization film.
As the material of the magnetic thin wire 11, the magnetic material of the perpendicular magnetization film such as Co / Pt or GdFeCo described above is used.

  By passing a current through the conductor wire 12, a magnetic field can be simultaneously applied to the four magnetic thin wires 11. By flowing a current independently through each of the magnetic thin wires 11, A magnetization pattern can be formed independently.

The magnetization pattern of the magnetic thin wire 11 may be formed by modulating the current flowing through the conductor wire 12 while flowing a constant current through each of the magnetic thin wires 11, or periodically changing the current flowing through the conductor wire 12. The current flowing through the magnetic thin wire 11 may be changed independently while being modulated.
In order to propagate the magnetization from the left to the right in the arrangement of FIG. 3, it is sufficient to pass a current through the magnetic thin wire 11 from the right to the left.

Further, the magnetic thin wire 11 may not be connected to a completely independent current source (transistor). For example, the left end of each magnetic thin wire 11 in FIG. It may be connected to a source.
If comprised in this way, the terminal to connect can be decreased.
In this configuration, it is preferable that the electrode of the magnetic thin wire 11 whose magnetization is to be moved is set to a high potential and the other two or more electrodes of the magnetic thin wire 11 are set to a low potential. As a result, a current larger than that of the other magnetic thin wires 11 flows through the magnetic thin wires 11 at a high potential, and the magnetization can be moved.

  FIG. 3 shows a configuration in which one conductor wire 12 is provided for the four magnetic thin wires 11, but one conductor wire is provided for a large number of magnetic thin wires to provide spatial light. A modulator may be configured. Further, a spatial light modulator may be configured by arranging a large number of combinations of magnetic thin wires and conductor wires on a plane.

According to the configuration of the spatial light modulator of the present embodiment described above, the conductor wire 12 is provided as a magnetization mechanism at the left end of the four magnetic thin wires 11. Thereby, the magnetic field can be applied to the magnetic thin wire 11 by the current magnetic field generated by the current flowing through the conductor wire 12, and the magnetization direction of the magnetic thin wire 11 in this portion can be reversed.
Furthermore, by passing an electric current through the magnetic thin wires 11, the magnetization state can be propagated in the magnetic thin wires 11, and a predetermined magnetization pattern can be formed on each magnetic thin wire 11.

Further, according to the configuration of the spatial light modulator of the present embodiment, it is possible to cover the area irradiated with light with a wide area ratio by the magnetic thin wire 11.
The light can be modulated in the magnetization state for each region of the continuous magnetic thin wire 11.
Therefore, compared with a spatial light modulator having a configuration in which individual light modulation elements are formed for each region, the area ratio of the portion contributing to modulation can be improved, and the electrode necessary for driving the spatial light modulator can be improved. It is possible to reduce the number of spatial light modulators by reducing the number.
The operation of changing the magnetization state of the magnetic thin wire 11 by the current magnetic field of the conductor wire 12 and the operation of causing a current to flow through the magnetic thin wire 11 and propagating the magnetization state in the magnetic thin wire 11 are relatively fast. Can be operated.

  Therefore, by using the spatial light modulator of this embodiment, it is possible to realize a stereoscopic image display device capable of displaying high-definition moving images and a hologram optical recording device capable of high-speed operation at high density. become.

<3. Second Embodiment>
4 and 5 show schematic configuration diagrams of the second embodiment of the spatial light modulator of the present invention. 4 shows a plan view and FIG. 5 shows a perspective view.
In the present embodiment, two groups of magnetic thin wires are arranged with the same configuration as that of the first embodiment as one group of magnetic thin wires.

As shown in FIG. 4, the first group of magnetic thin wires 11 and the second group of magnetic thin wires 13 each having a plurality of striped magnetic thin wires formed in parallel on the same plane, They are alternately arranged in parallel. A conductor wire 12 is disposed at the left end of the first group of magnetic thin wires 11, and a conductor wire 14 is disposed at the right end of the second group of thin magnetic wires 13.
Then, as shown in FIG. 5, the first group of magnetic thin wires 11 and the second group of magnetic thin wires 13 are formed on different planes, and the second group of magnetic thin wires 13 of the first group It is formed below the magnetic thin wire 11.
That is, a plurality of stripe-shaped magnetic thin wires are formed in parallel on the same plane, and two layers of magnetic thin wires are formed on different planes.

  As shown in FIG. 4, since the first group of magnetic thin wires 11 and the second group of magnetic thin wires 13 do not overlap on a plane, light is transmitted through the gap between the first group of magnetic thin wires 11. The magnetic thin wire 13 of the second group is reached. It is preferable that the first group of magnetic thin wires 11 and the second group of magnetic thin wires 13 are insulated by a transparent insulating layer so that light is sufficiently transmitted.

  In the spatial light modulator of the present embodiment, when forming the pattern of magnetization of the magnetic thin wires 11, 13, a current is passed through the first group of magnetic thin wires 11 from the right to the left so that the conductor The magnetization state generated by the current magnetic field of the line 12 is propagated from left to right. In addition, by flowing a current through the second group of magnetic thin wires 13 from left to right, the magnetization state generated by the current magnetic field of the conductor wire 14 is propagated from right to left.

  In this embodiment, the currents of the upper and lower magnetic thin wires 11 and 13 are made to flow in reverse, but if the magnetic field generating mechanisms are aligned on the left and right sides, the direction of the current flowing through the magnetic thin wires is the same.

According to the configuration of the spatial light modulator of the present embodiment described above, the conductor wire 12 is provided as a magnetization mechanism at the left end portion of the first group of magnetic thin wires 11, and the right end of the second group of magnetic thin wires 13 is provided. The conductor wire 14 is provided in the part as a magnetization mechanism. Thereby, a magnetic field can be applied to the magnetic thin wires 11 and 13 by a current magnetic field generated by a current flowing through the conductor wires 12 and 14, and the magnetization direction of the magnetic thin wires 11 and 13 in this portion can be reversed.
Furthermore, by passing a current through the magnetic thin wires 11 and 13, the magnetization state can be propagated in the magnetic thin wires 11 and 13, and a predetermined magnetization pattern can be formed on each of the magnetic thin wires 11 and 13.

In addition, according to the configuration of the spatial light modulator of the present embodiment, the first embodiment includes the first group of magnetic thin wires 11 and the second group of magnetic thin wires 13 that do not overlap in plan. As compared with the spatial light modulator, it is possible to cover a region irradiated with light with a wider area ratio.
Then, light can be modulated in the magnetization state for each region of the continuous magnetic thin wires 11 and 13.
Therefore, compared with a spatial light modulator having a configuration in which an individual light modulation element is formed for each region, the area ratio of the portion contributing to modulation can be greatly improved, which is necessary for driving the spatial light modulator. By reducing the number of electrodes, the price of the spatial light modulator can be reduced accordingly.
Then, the operation of changing the magnetization state of the magnetic thin wires 11 and 13 by the current magnetic field of the conductor wires 12 and 14 and the current flow in the magnetic thin wires 11 and 13 to change the magnetization state in the magnetic thin wires 11 and 13. The propagating operation can be performed at a relatively high speed.

  Therefore, by using the spatial light modulator of this embodiment, it is possible to realize a stereoscopic image display device capable of displaying high-definition moving images and a hologram optical recording device capable of high-speed operation at high density. become.

<4. Third Embodiment>
FIG. 6 shows a schematic configuration diagram (plan view) of the third embodiment of the spatial light modulator of the present invention.
In the present embodiment, the magnetic thin wires are linear in each of the previous embodiments, but the magnetic thin wires are combined into long magnetic thin wires that are bent and meandered. Also, spin injection torque is used as the magnetization mechanism of the magnetic thin wire.

As shown in FIG. 6, one magnetic thin wire 21 is bent so that straight portions and curved portions are alternately continued.
A magnetization mechanism 22 is provided at the lower left end of the magnetic thin wire 21.
When a voltage is applied to the upper left end of the magnetic thin wire 21, a current I <b> 2 that flows through the magnetic thin wire 21 is supplied.
The lower left end of the magnetic thin wire 21 is connected to the ground potential (ground potential).
The magnetization mechanism 22 is supplied with a pulse current I3 having a relatively short pulse width.

If the voltage applied to the upper left end of the magnetic thin wire 21 is positive, the magnetization of the magnetic thin wire 21 moves from the ground potential side to the voltage application side.
Here, when polarized electrons are taken in and out of a part of the magnetic thin wire 21 on the ground side from a magnetic material whose magnetization is fixed, the magnetization of the magnetic thin wire 21 near the magnetization mechanism 22 changes.
A cross-sectional view of one embodiment of the magnetization mechanism 22 is shown in FIG. On the magnetic thin wire 21, a magnetic body 24 whose magnetization is fixed and an antiferromagnetic body 25 that fixes the magnetization of the magnetic body 24 are laminated via a non-magnetic body 23.

Then, by supplying the current I3 from the antiferromagnetic material 25 side, the magnetization direction of the lower portion of the magnetization mechanism 22 of the magnetic thin wire 21 of the current I3 is made upward or downward by the action of the spin injection torque. Is set.
If the polarity of the spin polarization is the same between the magnetic body 24 whose magnetization direction is fixed and the magnetic thin wire 21, the magnetization of the magnetic thin wire 21 is caused when the current I 3 is passed from the magnetic thin wire 21 to the magnetic body 24. Is parallel to the magnetization of the magnetic body 24. When the current I3 is passed from the magnetic body 24 to the magnetic thin wire 21, the magnetization of the magnetic thin wire 21 becomes antiparallel to the magnetization of the magnetic body 24.
Further, when the polarities of the spin polarizations of the magnetic body 24 and the magnetic thin wire 21 are opposite, when the current I3 is passed from the magnetic thin wire 21 to the magnetic body 24, the magnetization of the magnetic thin wire 21 is changed to the magnetic material. It becomes antiparallel to the magnetization of 24. When the current I3 is passed from the magnetic body 24 to the magnetic thin wire 21, the magnetization of the magnetic thin wire 21 is parallel to the magnetization of the magnetic body 24.
In this way, the direction of the magnetization of the magnetic thin wire 21 is set by the direction of the current I3 flowing through the magnetization mechanism 22, and the current I 2 flows through the magnetic thin wire 21, thereby forming a magnetization pattern in the magnetic thin wire 21. be able to,

According to the configuration of the spatial light modulator of the present embodiment described above, the magnetization mechanism 22 using the spin injection torque is provided at the end of the magnetic thin wire 21. As a result, the direction of magnetization of the magnetic thin wire 21 in the portion of the magnetization mechanism 22 can be reversed by the current I3 flowing through the magnetization mechanism 22 and the spin injection torque.
Furthermore, by passing the current I2 through the magnetic thin wires 21, the magnetization state can be propagated in the magnetic thin wires 21, and a predetermined magnetization pattern can be formed on each magnetic thin wire 21.

In addition, according to the configuration of the spatial light modulator of the present embodiment, it is possible to cover the area irradiated with light with the magnetic thin wire 21 with a wide area ratio.
The light can be modulated in the magnetization state for each region of the continuous magnetic thin wire 21.
Therefore, compared with a spatial light modulator having a configuration in which individual light modulation elements are formed for each region, the area ratio of the portion contributing to modulation can be improved, and the electrode necessary for driving the spatial light modulator can be improved. It is possible to reduce the number of spatial light modulators by reducing the number.
Then, the operation of changing the magnetization state of the magnetic thin wire 21 by the spin injection torque caused by the current I3 flowing through the magnetization mechanism 22 and the current I2 flow in the magnetic thin wire 21 to propagate the magnetization state in the magnetic thin wire 21. The operation can be performed at a relatively high speed.

  Therefore, by using the spatial light modulator of this embodiment, it is possible to realize a stereoscopic image display device capable of displaying high-definition moving images and a hologram optical recording device capable of high-speed operation at high density. become.

  In addition, the position of the linear portion of the single magnetic thin wire 21 having the straight portion and the curved portion shown in FIG. By arranging the thin wire 21, it is also possible to obtain the same operation effect as the second embodiment.

<5. Modification>
In each of the above-described embodiments, the widths of the magnetic thin wires 11, 13, and 21 are substantially constant. On the other hand, in the present invention, the width of the magnetic thin wire and the position of the side surface may be periodically changed.
As a modification of the embodiment of the present invention, plan views of forms of magnetic thin wires having shapes in which the width and the position of the side surface are periodically changed are shown in FIGS. 8A to 8D.

FIG. 8A shows a form in which the width of the magnetic thin wire is changed linearly.
FIG. 8B shows a form in which the width of the magnetic thin wire is changed in a curved line.
FIG. 8C shows a form in which the same change as in FIG. 8A is performed on only one side surface of the magnetic thin wire and the other side surface is linear.
FIG. 8D shows a form in which the width of the magnetic thin wire is constant and the position of the side surface is changed linearly.
In each form shown in FIGS. 8A to 8C, the current density flowing through the magnetic thin wire is changed by changing the width of the magnetic thin wire, so that the ease of movement of magnetization partially changes. Thereby, since the location where the domain wall which is a boundary of magnetization is easy to stop can be set, magnetization can be moved stably.
In the form shown in FIG. 8D as well, the change in the position of the side surface causes a change in the ease of movement of magnetization due to a magnetic action.

In each form shown in FIGS. 8A to 8D, the width of the magnetic thin wire and the position of the side surface are changed.
Also, the thickness of the magnetic thin wire can be changed by changing the thickness of the magnetic thin wire, changing the magnetization and damping constant by adding an additive to the magnetic thin wire, etc. It is possible to obtain the same effect by changing the specific resistance.

The current flowing through the magnetic thin wire may be a constant current. However, as described above, it is effective to use the current waveforms as shown in FIGS. 9A to 9C in the configuration in which the width and thickness of the magnetic thin wire are changed. It is.
FIG. 9A shows a waveform in which the current decreases from the middle. When a small current value is set to a size that moves in a portion where the magnetic wall of the magnetic thin wire moves easily and does not move in a portion where the magnetic wall does not move easily, the domain wall does not move easily. Since the domain wall stably stops at the part, the magnetization can be easily controlled.
FIG. 9B shows a current waveform as a combination of two large and small pulses.
FIG. 9C shows a current waveform that decays.
Further, the current waveforms shown in FIGS. 9A to 9C may be combined.
9B and 9C, it is preferable to set the magnitude of the small pulse and the latter half of the attenuation pulse to a magnitude that moves in a portion where the domain wall easily moves and does not move in a portion where the domain wall hardly moves.

  8A to 8D, the configuration in which the width and thickness of the magnetic thin wire and the position of the side surface are periodically changed are the configurations of the first to third embodiments described above. Or it can be combined with each structure of embodiment mentioned later.

<6. Fourth Embodiment>
Next, a fourth embodiment of the spatial light modulator of the present invention will be described with reference to FIGS.
In this embodiment, a magnetic core that generates a magnetic field is used as a magnetization mechanism, and a region having magnetization in the in-film direction is provided at the end of a magnetic thin wire made of a perpendicular magnetization film.

First, as a comparison with this embodiment, FIGS. 10A to 10C show a case where the direction of magnetization is reversed by a magnetic field from a magnetic core with respect to a magnetic thin wire made of a perpendicular magnetization film. 10A shows a perspective view, FIG. 10B shows a top view, and FIG. 10C shows a cross-sectional view. In addition, the X axis, the Y axis, and the Z axis are added for easy understanding of the direction.
A magnetic core 42 is disposed on the left end of the magnetic thin wire 41 made of a perpendicular magnetization film.
10B and 10C, when the downward magnetization 46 is changed to the upward magnetization 47, the magnetization of the magnetic thin wire 41 below the magnetic core 42 must be reversed from downward to upward, and a large magnetic field 43 is required.

In contrast, in the present embodiment, a portion (region) having a magnetization 48 in the in-plane direction is provided at the left end of the magnetic thin wire 41 as shown in FIGS. 11A to 11C and FIGS. 12A to 12C. It has a configuration.
Specifically, the magnetization 48 of this portion (region) is directed to the back side in the in-plane direction (the + side of the Y axis). The magnetization in the in-film direction may be on the near side in the in-film direction (the negative side of the Y axis).

  In order to form such a portion (region) of the magnetization 48 in the in-plane direction, there is a method of reducing the perpendicular magnetic anisotropy by locally heating the portion or ion implantation. Also, there is a method in which an in-plane magnetization film having magnetization in the other film in-plane direction is arranged directly or via a non-magnetic film that mediates magnetic interaction with respect to the magnetic thin wire 41 made of a perpendicular magnetization film. is there.

FIG. 11A to FIG. 11C show the magnetization states of the magnetic thin wire 41 at a certain point when the upward magnetic field 44 is applied to the magnetic core 42 in the configuration of the present embodiment. From the state shown in FIGS. 11A to 11C, when a current is passed through the magnetic thin wire 41, the magnetization in the slightly upward direction (z direction) in the vicinity of the magnetic core 42 propagates to the right. Since the influence of the magnetization 48 becomes smaller, the upward magnetization becomes stronger. As a result, the downward magnetization on the right side of FIG. 11C is reversed upward.
Similarly, FIGS. 12A to 12C show the magnetization state of the magnetic thin wire 41 at a certain point when the downward magnetic field 45 is applied to the magnetic core 42 in the configuration of the present embodiment. The state shown in FIGS. 12A to 12C is a state when a current is passed through the magnetic thin wire 41 by applying a downward magnetic field 45 to the state where the magnetic thin wire 41 is magnetized downward. As it goes to the right of the magnetic thin wire 41, the influence of the magnetization 48 in the in-film direction becomes smaller, and the downward magnetization becomes stronger. Further, since the downward magnetic field 45 is applied to the state where the magnetic thin wire 41 is in the downward magnetization, the downward magnetization of the magnetic thin wire 41 does not change.
Since the portion of the magnetization 48 in the in-plane direction and the perpendicular magnetization film having the perpendicular magnetization are magnetically continuous, a domain wall is generated without any external action such as a magnetic field.
Since the magnetic fields 44 and 45 are applied to the periphery of the domain wall from the magnetic core 42, the magnetization direction of the magnetic thin wire 41 is reversed with a weak magnetic field as compared with the magnetic field 43 having the comparative configuration shown in FIG. Therefore, power saving during operation can be reduced.

According to the configuration of the present embodiment described above, the same operational effects as those of the above-described embodiments can be obtained. That is, it is possible to improve the area ratio of the portion contributing to the modulation and reduce the price of the spatial light modulator by comparing the spatial light modulators having the configuration in which individual light modulation elements are formed for each region. . And it can be operated at a relatively high speed.
Therefore, by using the spatial light modulator of this embodiment, it is possible to realize a stereoscopic image display device capable of displaying high-definition moving images and a hologram optical recording device capable of high-speed operation at high density. become.

Further, according to the configuration of the present embodiment, the left end portion of the magnetic thin wire 41 has the magnetization 48 in the in-film direction, so that this portion can be magnetized with a smaller magnetic field than the configuration in which the magnetization is perpendicular. The direction can be changed.
Thereby, it is possible to reduce the power consumption due to the operation of the magnetization mechanism.
In addition, it is possible to shorten the time required for the operation of changing the magnetization and speed up the operation.

<7. Fifth embodiment>
Next, a fifth embodiment of the spatial light modulator of the present invention will be described together with its manufacturing method.
The present embodiment is different from the above-described embodiments in that the magnetization mechanism is provided at substantially the center of the magnetic thin wire.

  The spatial light modulator of the present embodiment can be manufactured as described below.

First, although not shown, a logic circuit for controlling the operation of the spatial light modulator is formed on the substrate. This logic circuit is manufactured using a general CMOS logic circuit.
Next, a contact electrode connected to the logic circuit and an insulating layer that insulates the electrodes from each other are formed on the substrate on which the logic circuit is formed. A perspective view of this state is shown in FIG. 13A, a cross-sectional view taken along the line DD ′ of FIG. 13A is shown in FIG. 13B, and a cross-sectional view taken along the line EE ′ of FIG. Hereinafter, the same applies to FIGS. 14 to 19.
As shown in FIGS. 13A to 13C, a contact electrode 102 and an insulating layer 103 are formed on the surface of a substrate 101 on which a logic circuit is formed. The contact electrodes 102 arranged on the left and right in FIG. 13A are contact electrodes for magnetic thin wires, and the two contact electrodes 102 before and after FIG. 13A are contact electrodes for conductor wires.

Next, as shown in FIGS. 14A to 14C, the groove 104 is formed by processing the portion of the insulating layer 103 where a conductor wire will be formed later.
Subsequently, a magnetic yoke for efficiently generating a magnetic field and a nonmagnetic good conductor are continuously formed, and then the surface is flattened. A CoFe alloy can be used as the material of the magnetic yoke, and the aforementioned nonmagnetic conductor material such as Cu can be used as the material of the nonmagnetic good conductor.
As a result, as shown in FIGS. 15A to 15C, the magnetic yoke 105 and the conductor wire 106 made of a nonmagnetic good conductor are formed in the groove. The conductor wire 106 is electrically connected to the contact electrode 102 through the magnetic yoke 105. Further, since the magnetic yoke 105 has a higher resistance than the conductor wire 106, a large amount of current flows through the conductor wire 106 when a current is passed between the contact electrodes 102 at both ends.

  Next, after forming an insulating layer so as to cover the surface, as shown in FIGS. 16A to 16C, the insulating layer 108 on the magnetic thin wire contact electrode 102 is removed to connect to the magnetic thin wire. To form a contact.

Next, as shown in FIGS. 17A to 17C, an underlayer (not shown) and magnetic layer 109 for forming magnetic thin wires, and a soft magnetic layer 110 for forming a counter yoke of the magnetic yoke 105 are formed. Are continuously formed.
The underlayer can be formed by stacking a Ta film having a thickness of 2 nm and a Ru film having a thickness of 3 nm.
The magnetic layer 109 is formed by alternately laminating a Co film having a thickness of 0.5 nm and a Ni film having a thickness of 0.5 nm on the base layer by repeating 10 cycles, and forming a Ru film having a thickness of 1.2 nm. A film can be formed.
The soft magnetic layer 110 can be formed of a NiFe alloy film having a thickness of 5 nm.

Next, as shown in FIGS. 18A to 18C, the soft magnetic layer 110 of the other part is removed except for the part facing the conductor wire 106 for generating the magnetic field and the magnetic yoke 105.
At this time, if the etching is performed under appropriate conditions using material-selective etching such as reactive ion etching, only the soft magnetic layer 110 is removed, and only the magnetic layer 109 for forming a magnetic thin wire is obtained. Can leave.

  Next, as shown in FIG. 19D, which is a cross-sectional view taken along the line FF ′ of FIGS. 19A to 19C and FIG. 19A, the magnetic layer 109 is processed by etching to form stripe-like magnetic thin wires 111. At this time, in order to form a lens in the next step, as shown in FIG. 19D, when the stripe of the magnetic thin wire 111 is formed, it is etched deeply to a part of the lower insulating layer 103.

Next, by forming an insulating layer under appropriate conditions, as shown in a cross-sectional view in the same cross section as FIG. 19D in FIG. Layer 112 is formed. As the insulating layer 112, for example, an Al ₂ O ₃ layer may be formed by RF bias sputtering.
The lens-shaped insulating layer 112 provides an effect of condensing light on the magnetic thin wire 111.

In this way, the spatial light modulator of the present embodiment can be manufactured.
In the present embodiment, in particular, since the magnetization mechanism composed of the conductor wire 106 and the magnetic yokes 105 and 110 is provided in the central portion of the magnetic thin wire 111, each of the magnetic thin wires 111 on both sides of the magnetization mechanism is magnetized. Can be set.
Further, in each of the above-described embodiments, the description has been made with the configuration in which the magnetization mechanism is formed on the magnetic thin wire, but in this embodiment, the conductor wire 106 is formed on the magnetic thin wire 111 and the magnetic yoke is formed. 105 and 110 are formed below and above the magnetic thin wire 111, respectively.

In the description of the manufacturing method described above, one element group of the magnetic thin wire 111 has been extracted and illustrated, but a spatial light modulator can be configured by regularly arranging a large number of element groups.
FIG. 21 shows a plan view of a part of the spatial light modulator in which a large number of element groups are regularly arranged in the configuration of the present embodiment.
Sixteen planar patterns are formed for one soft magnetic layer (magnetic yoke) 110 with stripe-shaped magnetic thin wires 111.
The soft magnetic layer (magnetic yoke) 110 and a conductor wire (not shown) below form a magnetization mechanism, and this magnetization mechanism is provided at the center of the magnetic thin wire 111. Therefore, the left and right magnetic thin wires 111 of the magnetization mechanism are arranged. It is possible to set the magnetization independently of each other. Therefore, substantially, 16 × 2 = 32 magnetic thin wires are formed by one element group to constitute one unit.

If the soft magnetic layer 110 is left as it is, reflected light that does not contribute to spatial light modulation may be generated.
Further, since the magnetization of the portion connected to the contact electrode 102 at the end of the magnetic thin wire 111 does not change, it does not contribute to spatial light modulation.
Therefore, it is preferable to cover these portions with a light-shielding material or with a metal film having an inclination that reflects light out of the optical axis. By adopting these configurations, unnecessary reflection can be suppressed, and the light modulation intensity of the spatial light modulator can be increased.

According to the configuration of the present embodiment described above, the same operational effects as those of the above-described embodiments can be obtained. That is, it is possible to improve the area ratio of the portion contributing to the modulation and reduce the price of the spatial light modulator by comparing the spatial light modulators having the configuration in which individual light modulation elements are formed for each region. . And it can be operated at a relatively high speed.
Therefore, by using the spatial light modulator of this embodiment, it is possible to realize a stereoscopic image display device capable of displaying high-definition moving images and a hologram optical recording device capable of high-speed operation at high density. become.

<8. Experimental example>
Here, a spatial light modulator was actually created by the manufacturing method described with reference to FIGS.
Specifically, a film thickness that is an in-plane magnetization film via a Ru film on a perpendicular magnetization film in which a Co film having a thickness of 0.5 nm and a Ni film having a thickness of 0.5 nm are alternately laminated. In the configuration in which a 5 nm NiFe alloy film was formed, samples were prepared by changing the thickness of the Ru film. That is, each sample having a Ru film thickness of 0.6 nm, 1.2 nm, and 2 nm, and a sample in which a NiFe alloy film was formed on a perpendicular magnetization film without forming a Ru film as a comparative reference ( Ru film (0 nm).

The anisotropic magnetic field of each sample and the amount of current flowing through the conductor wire necessary for the magnetization reversal of the magnetic thin wire 11 were examined when each sample was formed into a striped magnetic thin wire 111.
Table 1 summarizes the thickness of the Ru film, the magnitude of the anisotropic magnetic field, and the magnetization reversal current of each sample. In Table 1, when the anisotropic magnetic field is positive, it is a perpendicular magnetization film, and when the anisotropic magnetic field is negative, it is an in-plane magnetization film.

From Table 1, when the thickness of the Ru film is 2 nm and it is a perpendicular magnetization film, the current required for magnetization reversal is large, but the reversal current is smaller in the in-plane magnetization film than in the perpendicular magnetization film.
In addition, when the Ru film was not formed, the reversal current was larger than when the Ru film was formed.
From the results in Table 1, it is considered that there is a correlation between the magnitude of the absolute value of the anisotropic magnetic field and the amount of current for magnetization reversal.

<9. Writing Method to Spatial Light Modulator>
Next, a method for writing a magnetization pattern to the spatial light modulator of the present invention will be described.
As an example, a case where writing is performed on four magnetic thin wires by a magnetization mechanism using a current magnetic field of a conductor wire will be described.
For example, consider the case where the data shown in Table 2 is written to each of the magnetic thin wire 1 to the magnetic thin wire 4. In Table 2, data of 0 and 1 indicate downward magnetization and upward magnetization, respectively.

Time variation of exciting current (corresponding to current I1 in FIG. 2) flowing in the magnetic field generating conductor wire for writing data shown in Table 2 and current flowing in each magnetic thin wire (corresponding to current I2 in FIG. 2) The initial part of is shown in FIG.
When the exciting current is positive, upward magnetization, that is, data of 1 is recorded. When the exciting current is negative, downward magnetization, that is, data of 0 is recorded.
When the pulse width of the current pulse is changed, the width of the magnetization pattern can be changed.

  Next, a pattern for recording all the data in Table 2 is shown in Table 3. In Table 3, the negative excitation current is set to-, the positive excitation current is set to +, 1 is set to flow current through the magnetic thin wire, and 0 is set to not flow current through the magnetic thin wire.

An arbitrary pattern other than the example shown in Table 3 can be recorded.
In addition, here, an example of recording on four magnetic thin wires has been shown, but when recording on 32 magnetic thin wires of one unit as shown in FIG. If this is done, recording can be performed on all the magnetic thin wires of one unit.
If other units are recorded at the same time, the recording can be quickly performed on the magnetic thin wire in the spatial light modulator.

When recording is performed on the magnetic thin wire of the spatial light modulator, light is not applied to the spatial light modulator.
Then, after the recording is completed, when the spatial light modulator is irradiated with coherent light, the light interferes according to the pattern recorded on the magnetic thin wire of the spatial light modulator, and the spatially modulated reflected light or Transmitted light can be obtained.

  The above-described writing method can be applied to any configuration in which a plurality of stripe-shaped magnetic thin wires are arranged (the first, second, fourth, and fifth embodiments described above). .

<10. Optical system when using spatial light modulator>
As a method of changing the intensity of light in a magnetized state, a magneto-magnetic interaction may be used for the Kerr effect, the Faraday effect, etc., which are generally well known. Colloids may be placed.

  Here, simple optical systems in the case of using the Kerr effect are shown in FIGS. 23 and 24, respectively.

FIG. 23 shows an optical system configured to make light incident on the spatial light modulator obliquely.
In the optical system 50 shown in FIG. 23, a light source 51, a lens 52, and a polarizer 53 are disposed in front of the spatial light modulator 54, and a polarizer 55 is disposed in the subsequent stage of the spatial light modulator 54. Yes.
The light from the light source 51 is incident on the spatial light modulator 54 obliquely.
When the light reflected by the spatial light modulator 54 is viewed directly or through a lens using the optical system 50, a stereoscopic image is displayed. That is, a display device can be configured using the optical system 50.

FIG. 24 shows an optical system configured to allow light to enter the spatial light modulator perpendicularly. 24, the same components as those in FIG. 23 are denoted by the same reference numerals.
In the optical system 60 shown in FIG. 24, a half mirror 56 is further provided in addition to the optical components of the optical system 50 shown in FIG. The half mirror 56 is arranged in a direction inclined by 45 degrees with respect to the reflection surface of the spatial light modulator 54.
The light from the light source 51 is reflected by the half mirror 56 and enters the spatial light modulator 54 perpendicularly. The light reflected by the spatial light modulator 54 passes through the half mirror 56 and passes through the upper polarizer 55.
When the light reflected by the spatial light modulator 54 is viewed directly or through a lens using the optical system 60, a stereoscopic image is displayed. That is, a display device can be configured using the optical system 60.

  In any optical system, other optical components such as a wavelength plate and a filter may be provided in addition to the illustrated optical components as necessary.

  In addition, for color display, a spatial light modulator may be prepared for each primary color, and the light from each spatial light modulator may be combined and displayed, or one spatial light modulation may be displayed. The color of the light source may be switched every time using a device.

Further, in the optical systems shown in FIGS. 23 and 24, the light from the light source 51 is reflected by the spatial light modulator 54 and used.
For the spatial light modulator of the present invention, as disclosed in Patent Document 2 (see FIGS. 1, 3, and 7), the light from the light source is transmitted through the spatial light modulator. An optical system may be configured.
When such an optical system is used and the light transmitted through the spatial light modulator is viewed directly or through a lens, a stereoscopic image is displayed. That is, a display device can be configured using such an optical system.

<11. Modulation method when using spatial light modulator>
Next, a modulation method in the case where light is modulated by arranging dispersed magnetic colloids on a magnetic thin wire will be described.
Since the magnetic colloid particles tend to gather at the domain wall, which is the magnetization boundary, the reflectance of light changes between the domain wall and the others, and the light intensity can be modulated.
When using a magnetic colloid, it is effective to provide a mechanism capable of applying a magnetic field or vibration in order to assist the movement of the colloidal particles.

A specific configuration using a magnetic colloid is shown in FIGS. 25A and 25B.
FIG. 25A shows a state in which the magnetic colloid is dispersed in a solvent.
A solvent in which colloidal particles 72 are dispersed is disposed on a magnetic thin wire 71 made of a perpendicular magnetization film. The solvent is covered with a protective glass 73.
In the magnetic thin wire 71, a domain wall 74 is formed at the boundary of the magnetization direction.

  When time elapses from the state of FIG. 25A, the colloidal particles 72 gather at a place where the leakage magnetic field 75 is strong in the vicinity of the domain wall 74, and the colloidal particles 72 aggregate near the domain wall 74 of the magnetic thin wire 71 as shown in FIG. As a result, the light reflectance of the portion where the colloidal particles 72 are aggregated changes, so that the light intensity can be modulated.

Next, a modulation method in the case where a magnetic fluid is arranged on a magnetic thin wire to modulate light will be described.
Since the magnetic fluid is also likely to gather at the domain wall that is the magnetization boundary, the reflectance of light changes between the domain wall and the others, and the intensity of the light can be modulated.

A specific configuration using a magnetic fluid is shown in FIGS. 26A and 26B.
FIG. 26A shows a state where the magnetic fluid has spread uniformly.
A magnetic fluid 76 spreads on a magnetic thin wire 71 made of a perpendicular magnetization film.
In the magnetic thin wire 71, a domain wall 74 is formed at the boundary of the magnetization direction.

  When time elapses from the state of FIG. 26A, the magnetic fluid 76 gathers in the strong magnetic field 75 near the magnetic wall 74, and the magnetic fluid 76 near the magnetic wall 74 of the magnetic thin wire 71 rises as shown in FIG. Unevenness is formed on the surface of the magnetic fluid 76. Thereby, since the reflectance of the light of the part which the magnetic fluid 76 rose is changed, the intensity | strength of light can be modulated.

  The configuration using the magnetic colloid 72 and the magnetic fluid 76 described above can be combined with the configurations of the first to fifth embodiments described above.

  The present invention is not limited to the above-described embodiment, and various other configurations can be taken without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Magnetic body, 2, 4 electrodes, 3, 12, 14, 106 Conductor wire, 5 Magnetization, 6, 7, 74 Domain wall, 11, 13, 21, 41, 71, 111 Magnetic body thin wire, 22 Magnetization mechanism, 23 Non Magnetic body, 24 magnetic body, 25 antiferromagnetic body, 42 magnetic core, 43, 44, 45, H magnetic field, 50, 60 optical system, 51 light source, 52 lens, 53, 55 polarizer, 54 spatial light modulator, 56 half mirror, 72 colloidal particles, 73 protective glass, 75 leakage magnetic field, 76 magnetic fluid, 101 substrate, 102 contact electrode, 103, 108, 112 insulating layer, 104 groove, 105 magnetic yoke, 109 magnetic layer, 110 soft magnetic layer , I1, I2, I3 currents,

Claims (9)

A spatial light modulator that reflects or transmits incident light and modulates the spatial intensity of the reflected or transmitted light;
A magnetic thin wire composed of a perpendicular magnetization film;
A magnetization mechanism for changing a magnetization state of a part of the magnetic thin wire;
A spatial light modulator comprising: a current supply mechanism that supplies a current in one direction into the magnetic thin wire and propagates the magnetization state changed by the magnetization mechanism in the magnetic thin wire.   2. The spatial light modulator according to claim 1, wherein the magnetization mechanism is configured to change the magnetization of the magnetic thin wire by an action of any one of a magnetic field, heat, and polarized spin injection.   2. The spatial light modulator according to claim 1, wherein the spatial light modulator includes a plurality of layers of the magnetic thin wires, and has a structure in which light is transmitted from a gap between the magnetic thin wires in the upper layer to the magnetic thin wires in the lower layer.   4. The spatial light modulator according to claim 3, wherein the magnetic thin-wire layer includes a plurality of stripe-shaped magnetic thin wires formed in parallel on the same plane.   The spatial light modulator according to claim 1, further comprising a solvent containing a magnetic colloid or a magnetic fluid disposed on the magnetic thin wire.   The spatial light modulator according to claim 1, further comprising a microlens made of a transparent insulating film, which is formed on the magnetic thin wire and is formed thick on the magnetic thin wire and thin at other portions.   The spatial light modulator according to claim 1, wherein the magnetic thin wire is formed such that any one of a width, a thickness, and a side surface position is periodically changed.   A magnetic material for in-plane magnetization in the in-plane direction is provided on a portion of the magnetic thin line in the vicinity of the magnetization mechanism so that the magnetization of the magnetic thin line in the portion is in the in-plane direction. The spatial light modulator according to claim 1, comprising: An electrode for electrically connecting one end of the plurality of magnetic thin wires in common;
A transistor individually connected to the other ends of the plurality of magnetic thin wires;
When changing the magnetization state of the selected n magnetic thin wires among the plurality of magnetic thin wires, the potential of the transistor connected to the selected n magnetic thin wires is increased. A logic circuit that is set to a potential and sets the transistors connected to n + 1 or more of the other unselected magnetic thin wires to have a low potential;
The spatial light modulator according to claim 1.

Images