JP3792917B2 - Imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging device, and more particularly to an imaging device that forms an image by reflection of natural light.
[0002]
[Prior art]
At present, it is well known as the Faraday effect that when a magnetic material is magnetized and linearly polarized light is incident parallel to the magnetization direction, the polarization plane of the light rotates by passing through the magnetic material. . A material having the Faraday effect and a magnetic recording medium using the material are manufactured.
[0003]
For example, Japanese Patent Publication No. 56-15125 (conventional example 1) discloses a magneto-optical material using yttrium and rare earth iron garnet and its derivatives. Japanese Patent Laid-Open No. 61-89605 (conventional example 2) discloses a magnetic recording medium using hexagonal ferrite. Furthermore, Japanese Patent Application Laid-Open No. 62-119758 (conventional example 3) discloses a coating type magnetic recording medium using yttrium iron garnet particles. Japanese Patent Laid-Open No. 4-132029 (conventional example 4) discloses a coating type magnetic recording medium using rare earth iron garnet fine particles.
[0004]
These magnetic recording media have a structure in which a magnetic material or magnetic particles are formed as a recording layer in a thin film on a substrate.
[0005]
When an image is displayed on such a magnetic recording medium and used as an imaging device, it is important that the display area is large and that it is flexible so that it can be easily handled.
[0006]
[Problems to be solved by the invention]
However, in the above-mentioned conventional examples 1 and 2, when a thin film method such as the PVD method (physical thin film forming method) is used, the film is highly transparent, but the magnetic material must be heated to a temperature of 400 ° C. or higher. Therefore, it is necessary to use a substrate with very high heat resistance such as quartz glass, and it is difficult to obtain a thin and flexible transparent substrate when such a heat resistant substrate is used. There was a problem. Further, in the above-mentioned conventional examples 3 and 4, since the powder magnetic material is applied onto the substrate together with the binder, the temperature during production can be low, but sufficient transparency in the visible light range cannot be obtained. was there.
[0007]
Therefore, in any conventional example, it has been difficult to produce an imaging device that uses the Faraday effect and has an image density that is high and the device itself is flexible and easy to handle.
[0008]
The present invention has been made to solve these problems, and it is an object of the present invention to provide an imaging device that can obtain a high-contrast image, has an appropriate flexibility, and is easy to handle.
[0009]
[Means for Solving the Problems]
  In order to solve the above problems, the present invention provides a reflective layer for forming a reflected image, and a first dielectric multilayer film configured by alternately and sequentially laminating a low refractive index dielectric and a high refractive dielectric. A transparent magnetic material having magnetic anisotropy in a direction perpendicular to the film surface, and a second dielectric multilayer film configured by alternately and sequentially stacking a high refractive index dielectric and a low refractive index dielectric Having a structure in which a structure laminated in order, a support, and a polarizer layer are laminated in order,Low refractive index dielectric is SiO ₂ The high refractive index dielectric is Ta ₂ O ₅ IsThere is a special feature. Therefore, the distance from the magnetic head at the time of magnetic recording can be reduced, an image with high contrast can be obtained, and an imaging device that is easy to handle can be provided by having appropriate flexibility.
[0010]
In addition, since the support is formed using a copolymer of octakis / hydridosilsesquioxane and bis / phenylethynyl / benzene, a rare earth iron garnet film that can be produced only at high temperatures can be used.
[0011]
Furthermore, the Faraday effect can be increased by stacking a plurality of structures.
[0012]
Further, by providing a protective layer under the reflective layer, damage such as scratches and peeling of the reflective layer can be prevented, and it can be used stably over a long period of time.
[0013]
Also, by newly providing a polarizer layer between the reflective layer and the first dielectric multilayer film of the structure, or by newly providing a polarizer layer between the reflective layer and the transparent magnetic material The image density was improved and an image with high contrast was obtained.
[0014]
And when the surface roughness of the reflective layer was 20 to 100 nm, light scattering occurred and the viewing angle increased.
[0015]
  Furthermore, as another invention, a reflective layer for forming a reflected image, a transparent magnetic material having magnetic anisotropy in a direction perpendicular to the film surface, a high refractive index dielectric, and a low refractive index dielectric It has a configuration in which dielectric multilayer films composed of alternating layers, a support, and a polarizer layer are sequentially stacked.The low refractive index dielectric is SiO ₂ The high refractive index dielectric is Ta ₂ O ₅ IsThere is a special feature. Therefore, it is possible to manufacture more easily while maintaining the effect of increasing the Faraday rotation angle.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
  Magnetic reflection in a direction perpendicular to the film surface, a reflective layer for forming a reflected image, a first dielectric multilayer film formed by alternately and sequentially stacking a low refractive index dielectric and a high refractive index dielectric. A structure in which a transparent magnetic material having directionality and a second dielectric multilayer film formed by alternately and sequentially stacking a high refractive index dielectric and a low refractive index dielectric, and a support, A polarizer layer was stacked in orderIn the imaging device of the present invention, the low refractive index dielectric is SiO. ₂ The high refractive index dielectric is Ta ₂ O ₅ It is.
[0017]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
First, the basic configuration of the imaging device according to the present invention will be described with reference to FIG. 1 showing the basic configuration of the imaging device. In the figure, an imaging device 1 according to the present invention includes a pair of dielectric multilayers in which a reflective layer 12 that enables a reflected image and two dielectrics having different refractive indexes of low refractive index and high refractive index are alternately laminated. The protective layer 11 includes a structure formed of the films 13 and 15, a transparent magnetic body 14 sandwiched between the pair of dielectric multilayer films, a support 16, and a polarizer layer 17 for visualizing the magnetization image. It has the structure laminated | stacked and provided in the single side | surface. According to the present invention having such a basic configuration, visible light incident from the side of the polarizer layer 17 becomes linearly polarized light in the polarizer layer 17, and this plane of polarization is the dielectric multilayer film 13 / transparent magnetic material in FIG. 14 / rotation is greatly caused by the structure of the dielectric multilayer film 15, and is further rotated after being reflected by the reflection layer 12, so that it cannot pass through the uppermost polarizer layer 17 and becomes dark. The light that has passed through the non-magnetized portion of the transparent magnetic body 14 is reflected as it is without rotation of the polarization plane, so that it passes through the polarizer layer 17 and becomes brighter. Therefore, contrast can be obtained between the magnetized portion and the non-magnetized portion. The first feature of the present invention is that a heat-resistant support that is opaque to visible light can be used by using a reflective imaging device having such a configuration. In this basic configuration, in particular, according to the structure in which the transparent magnetic body 14 is sandwiched between the pair of dielectric multilayer films 13 and 15, the light is confined in the transparent magnetic body 14 and the Faraday rotation angle is increased, resulting in higher contrast. A high image can be obtained. Further, as shown in FIG. 2, if this structure is repeated (two in FIG. 2), the contrast becomes higher. A transparent magnetic body 18 is provided between the structures, and the reflective film 12 is provided only between the dielectric multilayer film 13 and the protective layer 11.
[0018]
In such a reflective imaging device, there are mainly two methods for magnetizing the magnetic layer. One is a method of magnetic recording from the polarizer layer side with a magnetic pen equipped with a permanent magnet or an electromagnet, and the other is from the support side using a magnetic head array (for example, coil pitch is 127 μm, image resolution is 200 dpi). It is a method of recording. It has been found that the latter method of recording from the support side has a major technical problem. The magnetic pen can relatively easily increase the magnetic field of the magnet, but it is difficult to generate a large magnetic field in a magnetic head array having a coil pitch of about 100 μm. That is, since the thickness of the conducting wire used for the coil cannot be increased, a large current cannot be passed, and the number of turns of the conducting wire cannot be increased.
[0019]
Furthermore, the problems listed below were found.
(1) In order to obtain a large magnetization, it is important that the transparent magnetic material can be recorded in an arrangement as close as possible to the magnetic head array. When the coil pitch is 127 μm, the surface magnetic field strength obtained by applying a current of 100 mA to the coil is about 1500 gauss. Therefore, it was found that when the distance from the coil is further increased, for example, greater than 50 μm, the magnetization of the magnetic layer becomes difficult due to a sharp decrease in magnetic field strength, and the image is not blurred and clear.
[0020]
(2) Further, such an imaging device is light even in a large area, particularly needs to be flexible, is heavy in the case of a quartz glass plate, and is very inconvenient and impractical because it easily breaks.
[0021]
(3) Another important thing for the support. There are various materials for transparent magnetic materials, but rare earth iron garnet is most suitable for materials with high transparency and a large Faraday rotation angle, so-called large figure of merit. However, this material has a high crystallization temperature, and when it is produced by the PVD method, a support temperature of 450 ° C. or higher is required. It was also found that the transmittance of the rare earth iron garnet magnetic film was higher when the support temperature during film formation was higher.
[0022]
{Circle around (4)} Finally, it was experimentally found that a surface average roughness (Ra) of 10 nm or less is necessary for forming a clear image.
[0023]
Of course, it must be non-magnetic.
[0024]
Therefore, only a special zirconia and polyimide film opaque to visible light, a metal foil, and the like were found in the support with little change at a high temperature. Therefore, a polarizer layer / dielectric multilayer film / transparent magnetic material / Dielectric multilayer film / reflective layer / support structure only, and in order to satisfy the above (1), (2), (3), and (4), it is most important to make the support thickness as thin as 50 μm or less. Met.
[0025]
Therefore, the present invention is used with the above-described basic configuration using a support that is transparent to visible light and has a flexibility that is not easily broken even when bent and has a heat resistance of 450 ° C. or higher. Thus, it was found that the above (1), (2), (3), and (4) can be satisfied. In addition, the dielectric multilayer film / transparent magnetic body / dielectric multilayer film / reflection layer has a large number of layers, but the thickness can be reduced to about 1 μm, and the current value of the magnetic head array can be increased to increase the magnetization strength. An image with high contrast can be formed without increasing the image quality. In this case, the support that is transparent to visible light, flexible, and has a heat resistance temperature of 450 ° C. or higher is obtained by using octakis / hydridosilsesquioxane and bis / phenylethynyl / benzene with a platinum catalyst. A copolymer prepared at room temperature and normal pressure is used. This copolymer has a structure in which a molecule having a silicon skeleton and a molecule having a benzene ring as a core are alternately bonded and has a name of “T8 diyne”. The copolymer was dissolved in a bath medium and applied to a substrate, and then dried to be processed into a transparent thin film.
[0026]
In the basic configuration of the present invention described above, the number of polarizer layers is one (see FIG. 1), but the polarization axes (absorption or transmission axes) of the two polarizer layers are changed between the polarization plane rotation part and the non-rotation part. When the rotation is made so that the contrast becomes the largest, the polarization plane rotation part is white because of transmitted light, and the non-rotation part cannot pass through both polarizers and appears black. Naturally, if the direction of magnetization is reversed (+ and-) and light and dark are produced on the same principle, the contrast is doubled and the effect is increased.
[0027]
It has been described above that the structure of the dielectric multilayer film 13 / transparent magnetic body 14 / dielectric multilayer film 15 in FIG. 1 is important in terms of increasing the Faraday rotation angle. The dielectric multilayer film 13 may be a so-called reflective layer. However, when the structure of the dielectric multilayer film 13 / transparent magnetic body 14 / dielectric multilayer film 15 in FIG. 1 is repeated (see FIG. 2), light passes unless the film closest to the support is replaced with a reflective layer. Will not.
[0028]
Further, the protective layer 11 of FIG.₂ , TaO_Five , ITO, ZrC, TiC, MgF₂ , Al₂ O_Three , MgO, BeO, ZrO₂ , Y₂ O_Three Inorganic materials such as these and mixtures thereof can be used. As the organic resin protective film, a photocurable resin composition or a thermosetting resin composition mainly containing a polymerizable monomer and an oligomer can be used. The thickness is preferably in the range of 1 to 30 μm.
[0029]
Furthermore, in the reflection layer 12 of FIG. 1, it is preferable that the surface roughness is small in order to increase the reflectance. However, in such an imaging device, it is difficult to see an image depending on the viewing direction with only specularly reflected light. Therefore, it was found that the surface of the reflective layer should be slightly roughened to increase the scattered light. It was found that the surface roughness in this case was 20 to 100 nm. As the reflective layer 12, a mixture of metal or metal oxide, metal nitride, metal carbide and the like, for example, Al, Cu, Ag, Au, Pt, Rh, Zr, Cr, Ta, Mo, Si, Pd Metals such as Hf, alloys thereof, alloys thereof, Zr oxides, Si oxides, Si nitrides, alloys of Al, Hf, Pd, and the like are preferable because of easy film formation. The film thickness is in the range of 10 to 300 nm, preferably in the range of 50 to 150 nm. A film | membrane is produced using various PVD and CVD methods.
[0030]
Further, the materials shown in FIG. 3 are used for the dielectric magnetic layers 13 and 15 in FIG. You may select suitably from these materials, and other than this, for example, you may be organic substance. Each film thickness of the multilayer film is preferably about 50 nm to 200 nm. For the purpose of increasing the magneto-optical effect at a specific wavelength (λ), the film thickness of the dielectric is λ / 4n (n is the refractive index of the dielectric at λ). In addition, when a pair of low refractive index and high refractive index dielectrics is formed as one pair, the number of pairs is not limited, but 3 to 20 layers are preferable in terms of performance or cost. The two dielectric multilayer films in contact with the transparent magnetic material preferably have exactly the same structure, but are not necessarily limited thereto. However, since the same dielectric is used as the type of film directly in contact with the transparent magnetic material, the stacking order is reversed.
[0031]
Furthermore, for the polarizer layer 16 in FIG. 1, various commercially available polarizing films, a high transmittance polarizer using a beam splitter, and the like are used. The polarizing film is roughly classified into a multi-halogen polarizing film, a dye polarizing film, and a metal polarizing film. Since the multi-halogen polarizing film uses iodine as a dichroic substance, it has flat characteristics over the entire visible region, but has a drawback of being weak against humidity, high temperature, and the like. Dye polarizing films are characterized by being highly resistant to heat, light, and humidity, although they are inferior to iodine in polarizing performance. Since the exposed surface of the polarizer layer is easily scratched, it is preferable to provide a protective film. The following various polarizers can also be used, but are not limited thereto.
[0032]
(1) There is a polarizing plate having excellent optical characteristics by arranging and fixing a polarizing layer including a large number of rod-shaped elements made of ferromagnetic fine particles in a certain direction on a substrate surface (Japanese Patent Laid-Open No. 1-93702). ).
[0033]
(2) Polarizers for light having a wavelength longer than 2.5 μm include a transparent substrate (silver bromide, polyethylene, etc.) with gold and aluminum lines drawn at minute intervals (written by Professor Katsuaki Sato, Tokyo University of Agriculture and Technology). "Modern human physics 1-light and magnetism" (published in 1988, page 103). This polarizer is called a wire grid polarizer. When the distance between the lines is d and the wavelength is λ, the transmitted light has a vibration plane perpendicular to the line for light with a wavelength of λ >> d. It uses the fact that it becomes linearly polarized light. For the mid-infrared (2.5 μm to 25 μm), a silver bromide substrate with gold wires drawn at intervals of d = 0.3 μm is used. For the far infrared (16 μm to 100 μm), d = 0.7 μm is applied to the polyerylene plate. In this case, aluminum is used. The degree of polarization is said to be about 97%.
[0034]
(3) A glass having polarization characteristics by arranging long stretched metallic silver in one direction in the glass itself, unlike conventional organic polarizing elements, heat resistance, moisture resistance, chemical resistance, Excellent resistance to laser. Infrared is mainly used, but there is a special specification for visible light.
[0035]
(4) As reported by the Tohoku University group, a polarizer with an aluminum surface anodized for infrared use to form alumina, a fine hole, and a metal such as Ni or Cu. Yes, it is called a microwire array.
[0036]
(5) Produced by Prof. Shojiro Kawakami of the Institute of Electrical Communication of Tohoku University around 1991. Ge (germanium) with a thickness of 60-80 mm by RF sputtering for visible light and SiO with a thickness of 1 μm₂ Are alternately laminated to a thickness of 60 μm. This is called a laminated polarizer. Figure of merit α measured at a wavelength of 0.6 μm_TE/ Α_TM(This ratio is the ratio of the attenuation constant to TE wave and TM wave) is close to 400, the extinction ratio measured at a wavelength of 0.8 μm is 35 dB, and the insertion loss is 0.18 dB. Is sufficient.
[0037]
(6) There is a reflection type polarizer (one of S and P polarized light is reflected and the other is allowed to pass through) which is made by stacking a plurality of thin films, and what is called a reflective polarizer is there.
[0038]
Further, the transparent magnetic material 14 shown in FIG. 1 may be a transparent magnetic material exhibiting a magneto-optical effect that has been generally used. However, a magnetic material having a large Faraday effect and a large so-called performance index is preferable. In particular, R_3-x A_x Fe_Five O₁₂However, 0.2 <x <2, R has a composition represented by a chemical formula representing at least one element selected from the group consisting of yttrium and rare earth elements, and A is Bi or Ce. And rare earth iron garnet and derivatives thereof,_3-x A_x Fe_5-y B_y O₁₂However, it represents at least one element selected from the group consisting of yttrium and rare earth elements including Bi or Ce, represented by 0.2 <x <2, 0 ≦ y <5. It is meant to include everything including the above. Various metals are used for B, but typically Al is used. Since the magneto-optical effect is most effective when the light traveling direction and the spin direction are parallel, these materials are preferably films having magnetic anisotropy perpendicular to the film surface. For these transparent magnetic materials, PVD methods such as general sputtering, vacuum evaporation, MBE, CVD methods, plating methods, and the like are used.
[0039]
Next, the first embodiment of the present invention will be described in detail. First, a copolymer of octamis / hydridosilsesquioxane and bis / phenylethynyl / benzene was prepared at normal temperature and pressure using a platinum catalyst. This copolymer was dissolved in a bath medium, applied to a quartz glass substrate, and then dried to be processed into a transparent support having a thickness of 80 μm. This support is transparent and can be easily bent by hand. On this support, using an ion plating method, SiO 2₂ (Low refractive index layer, refractive index n = 1.47) 88 nm, Ta₂ O_Five (High refractive index layer, n = 2.15) was set to 61 nm, and six layers were alternately laminated in a total of 12 layers. Substrate temperature is 300 ° C, oxygen gas pressure is SiO₂ In case of 1.0 × 10^-FourTorr, Ta₂ O_Five In case of 1.1 × 10^-FourIt was Torr. The deposition rate is SiO₂ In the case of 2 nm / second, Ta₂ O_Five In this case, it was 0.5 nm / second. Regarding the film thickness distribution of each dielectric film, the difference between the thickest part and the thin part was 3% of the total film thickness. A Bi-substituted rare earth iron garnet film was formed on the dielectric multilayer film by ion beam sputtering so that the average film thickness was 520/2 = 260 nm. The substrate temperature was 550 ° C. The composition of the film is Bi_2.2 Dy_0.8 Fe_3.8 Al_1.2 O₁₂Met. From the wavelength dependence of the Faraday rotation angle measured with a magneto-optical effect measuring device (K250 manufactured by JASCO Corporation, beam diameter 2 mm square), the half width of the peak was 20 nm. At a wavelength of 520 nm, the peak value of the rotation angle was 1.8 degrees. The coercive force measured by applying a magnetic field perpendicularly to the film surface with VSM was 640 Oersted. Next, using this ion-plating method on this Bi-substituted rare earth iron garnet film, just like the above, SiO₂ And Ta₂ O_Five A multilayer film was prepared. The film in contact with the Bi-substituted rare earth iron garnet film is Ta₂ O_Three And the outermost surface side is SiO₂ It is. From the wavelength dependence of the Faraday rotation angle, the rotation angle was 11.5 degrees, which is about 6 times the 1.8 at the wavelength of 520 nm.
[0040]
A dielectric multilayer film 13 / transparent magnetic body 14 / dielectric multilayer film 15 structure shown in FIG. 1 was produced twice on the film produced as described above. At a wavelength of 520 nm, the rotation angle was 21.1 degrees. Further, the half-value width of the rotation angle peak centered on the wavelength of 520 nm was 73 nm.
[0041]
On the multilayer structure produced as described above, an Al film was produced using a vacuum deposition method so as to have a thickness of 200 nm. Furthermore, 1 μm thick SiO 2 is sputtered on the Al film.₂ A film was prepared as a protective film.
[0042]
And the commercially available iodine type film polarizer was affixed on the support surface in which this multilayer structure is not formed.
[0043]
Next, a magnetic head array was produced as follows. Only one line was produced by electroless plating so that a circular coil of copper wire with a pitch of 150 μm had a total length of about 50 mm. The electromagnetic coil copper wire had a width of about 5 μm and a depth of about 10 μm, three layers, and the total number of coil turns was 12 turns. Permalloy (Ni 80%) was produced at the center of the coil by electroplating so that the magnetic flux was concentrated in a cylindrical shape.
[0044]
A composition of polarizer / (dielectric multilayer film / transparent magnetic layer / dielectric multilayer film) × 3 / Al reflective layer / zirconia support was placed on the magnetic head array thus fabricated. A solid black image was obtained by passing a current of 100 mA in 10 msec order sequentially through all the electromagnetic coil arrays. The surface magnetic field strength at the center of the coil was 1660 gauss. The contrast of the image part with respect to the unrecorded part of the produced imaging device (FIG. 1) was 5.6.
[0045]
Here, a comparison between the following comparative examples and the following examples, which are conventional methods, will be described.
[0046]
In the first comparative example, an imaging device was fabricated so as to be exactly the same as the first example except that a rare earth iron garnet film not substituted with Bi and a Ba ferrite film were used instead of the Bi substituted rare earth iron garnet film. When the rare earth iron garnet film without Bi substitution was used, the contrast was 2.2, and when the Ba ferrite film was used, the contrast was 1.6, both of which were low.
[0047]
In the second comparative example, an imaging device was fabricated so as to be exactly the same as the first example except that a 0.5 mm thick quartz glass and a 50 μm thick copper foil were used. When quartz glass with a thickness of 0.5 mm was used, it was damaged by being dropped heavy. When copper foil having a thickness of 50 μm was used, an image could not be seen because it was opaque.
[0048]
In the third comparative example, an imaging device was produced so as to be exactly the same as the first example except that the protective film was not provided on the Al reflective layer. In this case, the Al film was easily scratched.
[0049]
Next, the second embodiment is the same as the first embodiment except that the Bi-substituted rare earth iron garnet film is formed as it is without providing the dielectric multilayer film 13 of FIG. 1 immediately above the reflective layer 12 in the imaging device of the first embodiment. An imaging device was fabricated so as to be the same as the example. The contrast of the image portion with respect to the unrecorded portion was 5.0.
[0050]
Further, the third embodiment is the same as the first embodiment except that a commercially available reflective polarizer is provided between the reflective layer 12 and the dielectric multilayer film 13 of FIG. 1 in the imaging device of the first embodiment. Imaging devices were made to be the same. Since two polarizers were used, the image density with respect to the unrecorded portion was improved and the contrast was 5.9.
[0051]
Further, in the fourth embodiment, a Bi-substituted rare earth iron garnet film is formed immediately without providing the dielectric multilayer film 13 of FIG. 1 immediately above the reflective layer 12 of FIG. 1 in the imaging device of the first embodiment. An imaging device was produced so as to be exactly the same as in the first example except that a commercially available reflective polarizer was provided between the reflective layer 12 and the dielectric multilayer film 13. Since two polarizers were used, the image density with respect to the unrecorded portion was improved, and the contrast was 6.0.
[0052]
Further, in the fifth example, when the AL reflective layer was manufactured after the final dielectric multilayer film was manufactured with the imaging device of the first example, an Al film having a thickness of 50 nm was first manufactured while flowing Ar gas at a flow rate of 30 ccm. did. At this time, the average surface roughness (Ra) of the Al surface was 26 nm. Thereafter, an imaging device was fabricated in the same manner as in the first example using a 200 nm thick Al film. The contrast of the image portion with respect to the unrecorded portion was 6.2, and the image could be observed from a wide field of view.
[0053]
In addition, this invention is not limited to the said Example, It cannot be overemphasized that various deformation | transformation and substitution are possible if it is described in a claim.
[0054]
【The invention's effect】
  As described above, according to the present invention, the reflective layer for forming the reflected image, and the first dielectric multilayer film configured by alternately and sequentially stacking the low refractive index dielectric and the high refractive index dielectric, A transparent magnetic material having magnetic anisotropy in a direction perpendicular to the film surface, and a second dielectric multilayer film configured by alternately and sequentially stacking a high refractive index dielectric and a low refractive index dielectric A structure in which layers of structures are stacked in sequence, a support, and a polarizer layer.The low refractive index dielectric is SiO ₂ The high refractive index dielectric is Ta ₂ O ₅ IsThere is a special feature. Therefore, the distance from the magnetic head at the time of magnetic recording can be reduced, an image with high contrast can be obtained, and an imaging device that is easy to handle can be provided by having appropriate flexibility.
[0055]
In addition, since the support is formed using a copolymer of octakis / hydridosilsesquioxane and bis / phenylethynyl / benzene, a rare earth iron garnet film that can be produced only at high temperatures can be used.
[0056]
Furthermore, the Faraday effect can be increased by stacking a plurality of structures.
[0057]
Further, by providing a protective layer under the reflective layer, damage such as scratches and peeling of the reflective layer can be prevented, and it can be used stably over a long period of time.
[0058]
In addition, by newly providing a polarizer layer between the reflective layer and the first dielectric multilayer film of the structure, or by newly providing a polarizer layer between the reflective layer and the transparent magnetic material, The image density was improved and an image with high contrast was obtained.
[0059]
And when the surface roughness of the reflective layer was 20 to 100 nm, light scattering occurred and the viewing angle increased.
[0060]
  Furthermore, as another invention, a reflective layer for forming a reflected image, a transparent magnetic material having magnetic anisotropy in a direction perpendicular to the film surface, a high refractive index dielectric, and a low refractive index dielectric It has a configuration in which dielectric multilayer films composed of alternating layers, a support, and a polarizer layer are sequentially stacked.The low refractive index dielectric is SiO ₂ The high refractive index dielectric is Ta ₂ O ₅ IsThere is a special feature. Therefore, it is possible to manufacture more easily while maintaining the effect of increasing the Faraday rotation angle.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing a laminated structure of a basic configuration of an imaging device according to the present invention.
FIG. 2 is a schematic cross-sectional view showing a laminated structure of an imaging device according to the first embodiment of the present invention.
FIG. 3 is a diagram showing a dielectric magnetic material of a dielectric multilayer film according to the present invention.
[Explanation of symbols]
1 Imaging device
11 Protective film
12 Reflective layer
13, 15 Dielectric multilayer film
14,18 Transparent magnetic material
16 Support
17 Polarizer layer

Claims (11)

Magnetic reflection in a direction perpendicular to the film surface, a reflective layer for forming a reflected image, a first dielectric multilayer film formed by alternately and sequentially stacking a low refractive index dielectric and a high refractive index dielectric. A structure in which a transparent magnetic material having directionality and a second dielectric multilayer film formed by alternately and sequentially stacking a high refractive index dielectric and a low refractive index dielectric, and a support, In an imaging device having a configuration in which a polarizer layer is laminated in order ,
The low refractive index dielectric is SiO _2, the imaging device, wherein the high refractive index dielectric is Ta ₂ O _5.   2. The measuring device according to claim 1, wherein the support is formed using a copolymer of octakis hydridosilsesquioxane and bis-phenylethynyl-benzene.   The imaging device according to claim 1, wherein a plurality of the structures are stacked.   The imaging device according to claim 1, wherein a protective layer is provided under the reflective layer.   The imaging device according to any one of claims 1 to 4, wherein a polarizer layer is newly provided between the reflective layer and the first dielectric multilayer film of the structure.   The imaging device according to claim 3, wherein a polarizer layer is newly provided between the reflective layer and the transparent magnetic body.   The imaging device according to claim 1, wherein the reflective layer has a surface roughness of 20 to 100 nm. A reflection layer for forming a reflection image, a transparent magnetic material having magnetic anisotropy in a direction perpendicular to the film surface, and a high refractive index dielectric and a low refractive index dielectric are stacked in this order and alternately. In an imaging device having a configuration in which a dielectric multilayer film, a support, and a polarizer layer are sequentially laminated ,
The low refractive index dielectric is SiO _2, the imaging device, wherein the high refractive index dielectric is Ta ₂ O _5.   9. The measuring device according to claim 8, wherein the support is formed using a copolymer of octakis hydridosilsesquioxane and bis-phenylethynyl-benzene.   The imaging device according to claim 8, wherein a protective layer is provided below the reflective layer.   The imaging device according to claim 8, wherein the reflective layer has a surface roughness of 20 to 100 nm.

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