JPS6012530A - Optical memory device - Google Patents

Abstract

PURPOSE:To enable writing and erasion and to obtain a fine pattern showing high contrast in a region up to infrared light by forming a film of an oxide contg. ions of one or more among W, Mo, Ir, Rh and Ni and a light element and by irradiating ultraviolet rays on the film to develop color. CONSTITUTION:Ultraviolet rays 8 from an ultraviolet light source 7 are converged with an optical system 9 and irradiated on an optical element 6 made of an oxide contg. ions of at least one among W, Mo, Ir, Rh and Ni and a light element to carry out writing. Infrared rays 11 from an infrared light source 10 are converged with an optical system 9 and irradiated on the element 6 to carry out erasion. When ultraviolet rays 8 are irradiated on the oxide of the element 6, the irradiated part develops color, and the color can be vanished by irradiating infrared rays 11 on the color developed part. A fine color pattern having high contrast in the visible region can be obtd. without requiring an electrode, a multilayered structure contg. an electrochromic layer, a polarizer or an external magnetic field.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to writeable and erasable optical memory devices.

Structures of conventional examples and their problems Tungsten, molybdenum, iridium, rhodium, and nickel oxides, which are known as electrochromic materials, contain light element ions and electron signatures.

When tungsten oxide is double-injected with Li ions and electrons, it undergoes a chemical change of WO3 + XLl + Xf3 - + LiXWO3 and is reduced to form tungsten bronze, changing from W on the left side to a mixture of W5+ and W6+ on the right side. The film changes from a transparent film to a blue film. This coloring is said to be due to absorption of light due to electron transition between W6+ and W5+.

-1; The chemical change described is conventionally performed by Li+ ion or H
This was caused by moving ions using an electric field and causing them to enter the WO3 film. For this reason, conventional optical elements using a WO3 film, as shown in FIG.
At least a multilayer structure in which a membrane 1 and an ion source 2 are sandwiched between electrodes 3 is required. The same applies to other metal oxide electrochromic elements. In addition, at least one of the electrodes must be transparent, and it is also necessary to take out the lead from the electrode 3, making it difficult to manufacture and requiring a fine structure to be used only as a simple display element. It has been difficult to apply this to optical memory devices. 4 is a base material.

The inventors have discovered that the oxide film containing the metal and light element sulfur basins can be colored by irradiating it with ultraviolet light, and can be decolored by irradiating it with thermal energy, such as infrared light. Based on this discovery, he invented an optical memory device that is easy to manufacture, can produce fine colored patterns, and is writable and erasable.

Unfortunately, conventional optical memory devices that can be written and erased utilize the magnetic Kerr effect, but this optical memory device has a structure as shown in Fig. An optical material film 19 is formed, and writing is performed by irradiating the film with a laser beam q having thermal energy through the optical system 9.

An external magnetic field is required during this writing, and for reading, the readout light 12 is irradiated through the entire polarizer 6, and the reflected light is further transmitted through the entire polarizer 6, and the intensity is read by the detector 15. This device requires a polarizer 5 and an external magnetic field, and as an optical memory device, requires, for example, a complicated external magnetic field structure, and the contrast is not very good, so it is not suitable for practical use. Moreover, there is no conventional optical memory device that does not require a polarizer and has good sensitivity in the recovery region.

OBJECTS OF THE INVENTION The present invention provides a simple optical memory device that is capable of writing and erasing, and is capable of realizing a fine pattern that exhibits good contrast in a region ranging from visible light to infrared light. The purpose is to

Composition of the invention The optical memory device according to the present invention is made of tungsten.

It is characterized in that an oxide containing at least one of molybdenum, iridium, rhodium, and nickel and ions of a light element is formed into a planar shape, and colored by being irradiated with ultraviolet light from an ultraviolet light source. Further, the colored portion is erased by irradiating infrared light from an infrared source.

DESCRIPTION OF EMBODIMENTS FIG. 3 shows the configuration of an embodiment of an optical memory device according to the present invention. An ultraviolet light source 7 is provided to the optical element 6 made of the above oxide.
The optical system 9 irradiates ultraviolet rays 8 from the infrared light source 1o for writing, and the optical system 9 irradiates the infrared rays 11 from the infrared light source 1o for erasing.

To read out the signal, read out (visible) light 12 using optical system 1.
3 and irradiates it, and the detector 16 detects the change in the intensity of the reflected light 14. The reading may also be performed by using the infrared light 11 as weak light and changing the intensity of the reflected light 16.

When the oxide of the optical element 6 is irradiated with ultraviolet light 8, that part becomes colored, and the color can be erased by applying infrared light 11 to the colored part. This allows for electrodes, multilayer structures (electrochromic), as before.

We have achieved a write-erasable optical memory device with good contrast, which can create a color pattern with high contrast in the fine visible region without the need for a polarizer or external magnetic field.

The mechanism of color development and decolorization described above will be explained next.

The above metal oxide is a light element ion, OH.

The valence of the metal atom changes depending on how the metal atom is bonded to H, Ll 2 , Na 2 , etc.

When electronic states with high-energy valence and low-energy valence exist, energy transition between them causes absorption of photons, which causes color development.

The colorless oxide film containing metal and light element ions is in the low energy state and is 77° stable. When ultraviolet light is irradiated here, the electronic state of the metal atoms is excited and the high energy state is induced. This is why it develops color. In other words, the film develops color when irradiated with ultraviolet light.

Furthermore, when infrared rays (thermal energy) are applied to this color-forming film, the ions of the above-mentioned light elements move more easily in the film, and are more likely to combine with metal atoms in a high-energy state that contribute to color development. In other words, it becomes easier to change to a more energetically stable state, so the high energy state disappears, and the color disappears. In other words, infrared rays (thermal energy) can erase the color of the color-forming film.

In the optical memory device according to the present invention, the optical memory pattern can be made like an optical disk by binding the ultraviolet rays with an optical system and rotating the above-mentioned optical element to form a dot-like object, or by scanning the writing ultraviolet rays, It is also possible to obtain dimensional images.

It is also possible to create a colored pattern by placing a mask over the optical element, rather than squeezing the ultraviolet light with a lens. Reading is not limited to reflected light, but can also be performed using transmitted light, and the written two-dimensional pattern can also be read out as it is without using a lens to block the readout light.

It can be erased partially by squeezing the infrared rays with a lens, or it can be erased entirely by irradiating all six bodies with infrared rays.

The inventors have confirmed that an excimer laser is particularly effective as the ultraviolet light source. By using excimer laser light, a finer, high-power spot can be obtained, and writing can be performed effectively.

The inventors also confirmed that a carbon dioxide laser is particularly effective as the infrared light source. If infrared laser light from a carbon dioxide laser is used, a finer, high-power spot can be obtained, and erasing can be performed effectively.

DESCRIPTION OF EMBODIMENTS FIG. 4 shows a write state of an optical memory device in an embodiment of the present invention. On the fused silica substrate 4''-,
An acid 9/'' diride film 16 containing lithium and tungsten is formed by sppack evaporation in an oxygen atmosphere.
An optical element having a coloring layer in a colorless amorphous state was obtained. In this case, the substrate 4 is not limited to fused silica, but may be any material that is stable against sputter deposition. Furthermore, the substrate 4 is not necessarily required as long as the coloring layer can be stably maintained.

This film is partially coated with ultraviolet 8 (excimer laser) wavelength 2.
When irradiated with 49 nm at a density of about 50 m J/ci, it was colored blue and exhibited optical absorption with a reflected light intensity of 10 dB or more in the He-Ne laser beam of 6328 people.
A colored portion 17 having a large contrast in the visible region was formed. Further, by condensing and irradiating the ultraviolet rays 8 with a lens, a colored portion with a size of 1 μm or less could be formed, and writing as a dot-shaped optical memory could be performed.

As shown in FIG. 5, an infrared ray 11 (CO3L/-the, wavelength 10.6 It m) is applied to the written colored part 17.
(By irradiating several times at a density of about 55W/α',
It was possible to erase to a colorless state similar to the surrounding area 18 where no writing was performed. By focusing the light at 10° with a lens, a dot-like erase pattern could also be formed.

Note that although only optical memory devices using oxides containing tungsten and lithium ions have been described here, lithium ions may also be hydrogen ions or ions of other light elements, and tungsten may include molybdenum, iridium, rhodium, nickel, etc. But that's fine. Furthermore, the metals tungsten, molybdenum, iridium, rhodium, and nickel may be used in combination with each other.

As described above, the present invention provides tungsten, molybdenum,
An oxide containing at least one of iridium, rhodium, and nickel and light element ions is formed into a planar shape, colored with ultraviolet rays and written on, and then erased with thermal energy such as infrared light. It is possible to realize an excellent optical memory device that is simple, writable and erasable, exhibits good contrast in the visible to infrared region, and is capable of realizing fine patterns. The industrial value of the present invention is incredible.
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[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional electrochromic element, Figure 2 is a schematic diagram of a conventional magneto-optical optical memory device, and Figure 3 is a schematic diagram of a conventional magneto-optical optical memory device.
4 is a schematic diagram of an optical memory device according to an embodiment of the present invention, FIG. 4 is a diagram of a write operation of the optical memory device of the present invention, and FIG. 5 is a diagram of an erase operation of the optical memory device of the present invention. 8...Ultraviolet light, 11...Infrared light, 12
. . . Read light, 16 . . . Oxide film containing lithium and tungsten, 17 . . . Writing pattern (colored portion). Name of agent: Patent attorney Toshio Nakao and 1 other person @
1 Figure 2

Claims (5)

[Claims] (1) An optical memory characterized by forming a planar oxide containing at least one of tungsten, molybdenum, indium, and rhodium-9-nickel and ions of a light element, and coloring it by irradiating it with ultraviolet light from an ultraviolet light source. Device. (2) The optical memory device according to claim 1, wherein the coloring portion is erased by irradiating infrared rays from an infrared light source. (3) The optical memory device according to claim 1, wherein an excimer laser is used as the ultraviolet light source. (4) The optical memory device according to claim 2, wherein a carbon dioxide laser is used as the infrared light source. (5) The optical memory device according to claim 1 or 2, wherein the planar oxide is composed of an oxide containing tungsten and lithium ions.