JPS6371950A - information storage carrier - Google Patents

Abstract

PURPOSE:To provide high C/N and to increase an erasing speed by applying the intensity of the electric field different from the electric field at the time of storing information to both terminals of two electrodes while heating a memory film or applying heating thereto the restore the amount film to the initial stable state in erasing of the information. CONSTITUTION:The inverted electric field is applied to the memory film at the time of erasing to transfer the film at a high speed to the state of the other optical constant which is stable by the projection of low-output laser light and heating. More specifically, the DC voltage is applied to the electrodes 2, 4 and the condensed laser light 5 is projected onto the memory film 3. The memory film 3 is transferred easily to the other stable state to exhibit the different reflectivity by the opto-thermo energy of the laser light 5 in addition to the excitation of the energy level by the electric field impression thus the erasing of information is executed. The reproduction of the information is attained by scanning the laser light on the memory film at the level lower than the quantity of the laser light at the time of storing and erasing the information and viewing the presence or absence of a change in the reflectivity of the memory film 3 to reproduce the information. The storage of the information is executed by condensing and projecting the laser light 4 onto the memory film 3 having the reflectivity in the erasing state and changing the same to the reflectivity state which is the memory state to end the storage.

Description

[Detailed Description of the Invention] [Field of Sedentary Work] The present invention relates to an optical memory capable of storing, erasing, and reproducing information, and particularly relates to a laser writing, erasing, and memory device suitable for high density and large capacity storage. Concerning playback memory.

[Conventional technology]

Optical disk memory using laser light has been developed as a high-density, large-capacity information storage carrier. Can you see an improvement in the conventional method? A method for transitioning between two states with different optical constants as an optical disk memory that can obtain a 14JC/N ratio was published in Japanese Patent Publication No. 60-23.
Although disclosed in Japanese Patent No. 995, a high-output laser beam is required to erase information, and the time required for erasing is limited to several rrLsec because heating and cooling phenomena are utilized.

However, an example of improving the erasing speed is "IEICE Technical Report Vot84.A203 'November 1984.
There is a magneto-optical disk that utilizes the Kerr rotation angle caused by the reversal of the magnetic field of the memory film, as shown in ``Moon'', but because the Kerr rotation angle is minute, a high 0/N ratio cannot be obtained. There was a problem.

[Problem that the invention seeks to solve]

The conventional technology described above does not take into account the IT information erasing speed in some cases, and the high C/N ratio in other cases, making it difficult to share the respective advantages.The purpose of the present invention is to The object of the present invention is to provide an information storage carrier having a high O/N ratio, a fast erasing speed, a high density, and a large capacity.

[Failure to solve the problem]

The above purpose is to provide a memory film between two electrodes, and the memory film is made of a material that can switch between two states with different optical constants, and when an electric field is applied, laser light irradiation and heating are performed. This causes a large change in optical constants, resulting in a high O/N ratio. Furthermore, during erasing, by applying an inverted electric field, other stable optical constants can be changed by applying a low-power laser, light irradiation, and heating. A high erasing rate is achieved by transferring the memory to a high-speed state. [Function] The requirements for a large-capacity, high-density memory are to focus the laser beam along the guide grooves formed on the substrate. This is achieved by storing, reproducing, and erasing information.

In addition, an example of controlling molecular orientation by applying an electric field to a substance is polyvinylidene (PVD).
, are found in various liquid crystals, etc., and these include those in which molecular orientation is fixed by applying an electric field during heating and cooling (PVDF), and those in which molecular orientation is obtained only when an electric field is applied. Among nematic liquid crystals with large ion polarizability, molecular orientation occurs only when a laser beam with an absorption edge wave* (cμt, ff') or less is applied and a voltage is applied, creating a state with central symmetry. It has been found that it metastasizes to (G,
R.

me r ed it A, etal: yttt
ero rnOLec, 1ttes, 15.2463
．． '84) This suggests that the energy threshold for state transition of matter is greatly reduced by the electric field and optical energy.

Se, which is conventionally used as a high-sensitivity recording memory film,
Sb, Te, etc. are ionically bonded9, and by laser heating using a semiconductor laser, the optical constant difference (especially the refractive index The recording mechanism is the difference '), and the stable storage of information is achieved by fixing the bonding state as it cools.

Therefore, in addition to the optical and thermal energy of the laser beam, the =m energy of the chalcogenide compound that utilizes the change in the state of ionic bonds is 1! It is possible to control the bound state by applying an L field and lowering the threshold of the transition energy of the bound state. In particular, the crystal phase (
By using a centrally symmetrical structure in conjunction with the application of an electric field, and by achieving state equivalence upon cooling, it is possible to achieve a higher speed than in conventional transitions using thermal energy. Furthermore, during recording, an amorphous state with no center symmetry is created by molecular vibrations caused by the optical and thermal energy of the laser beam, and the recording state is easily achieved as the material is cooled.

〔Example〕

Examples of the present invention will be described below. Figure 1 shows:
FIG. 1 is a diagram showing an embodiment of the present invention.

A transparent NESA film 2 was formed on a glass substrate 1α, and a memory group 3 made of a chalcogenide compound having an alft5 of a memory film was formed by sputtering. A layer t was deposited on the upper layer of the memory group 3 to form the other electrode 4. A direct current voltage is applied to the electrode 2.4 configured in this manner, and the laser beam 5 is irradiated onto the memory film 5. The light and heat energy caused by the light and heat can easily transition to another stable state exhibiting a different reflectance, and the information will be erased. Information can be reproduced at a lower level than the laser beam cover when erasing information, and the memory film 3
This can be achieved by scanning the top of the memory film 60 and checking for changes in the reflectance of the memory film 60. When storing information, the laser beam 4 is condensed and irradiated onto the memory film 3 having a reflectance that is in the erased state, and the process is completed by changing the reflectance state to the stored state.

FIG. 2 is a diagram showing another embodiment, and is a partial cross-sectional view when an optical disk is formed which can achieve high density and large capacity. The substrate 1b is a glass substrate with a thickness of 1.1 mm, and a guide '#46 with a track pitch of 16 μm is formed by a photovolimerization process (2P process), as described in Example 1 below.
In the same manner as above, a NESA film 2, a memory film 3, and an electrode 4 were formed.

Furthermore, in this example, a protective film 7 made of ultraviolet-cured resin was formed to protect the electrode 4. The storage, reproduction, and erasing characteristics of the information storage carrier constructed in this manner were similar to those in Example 1. Further, by applying a cleaning agent on the moisture retaining film, it is possible to create a structure that can be used on both sides.

FIG. 3 is a partial cross-sectional view showing an embodiment of an optical disk that is capable of high sensitivity, high density, and large capacity. The substrate 1b is a polymethyl methacrylate (PMMA) substrate with a thickness of 1.2 ws. The guide groove 6 (not shown) is formed by simultaneous transfer using an injection molding method. A NESA film 2 was formed on this substrate 1b by vacuum evaporation, and a memory film 3 was formed on top of this in the same manner as in the embodiment described above.

On this memory film 3, in order to effectively apply an electric field, an organic semiconductor film 8 which is insulating at room temperature and has a negative temperature/resistance coefficient is formed, and an electrode 4 and a protective film 5 are formed. With this structure, a part of the thermal energy of the laser beam 5 consumed when erasing information can be efficiently applied to the memory film 3. That is, in Example 12, both ends of the memory film 3 are Because it is composed of an inorganic substance with a high thermal conductivity rate, heat loss to areas other than the memory gland 6 is large, making it difficult to obtain P amount sensitivity.In this example, the thermal conductivity is small compared to inorganic substances. By using a polymer material as the substrate 1b and further forming an organic semiconductor film 8 on the other surface,
Loss of thermal energy is prevented and sensitivity can be achieved. Examples of organic semiconductor group 8 include fully conjugated π-electron thread polymers such as poly-P-phenylene, planar conjugated polymers such as anthracene, metal chelate polymers such as polysteel phthalocyanine, polyvinyl carbazole, and trinitrofluorenone. A charge transfer complex type polymer consisting of the following can be used.

As described in detail in the above examples, chalcogenide compounds (Se-Sb
-Bi, TeOx) can be used, and high
/N ratio is obtained. In addition, by using an electric field as bias energy, the thermal energy applied to the memory film is small, reducing the time required for heating and cooling, and improving the erasing speed. Although a disk form is shown as the form of the carrier, it goes without saying that similar effects can be obtained using other forms such as tape, card, and chip.

Further, in this example, a chalcogenide compound has been described, but it goes without saying that similar effects can be found with other ionic or coordinate bonded substances.

〔Effect of the invention〕

According to the present invention, it is possible to provide an information storage carrier that has a high O/N ratio, is capable of fast erasing, and has a simple structure and is capable of achieving high density and large capacity distribution.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view showing one embodiment of the present invention, FIG. 2 is a partial cross-sectional view showing another embodiment, and FIG. 5 is a partial cross-sectional view showing still another embodiment. 1...Substrate 2...Transparent 'Sa and others 3...Memory film 4...1! Others 5...Laser beam 6...Guide groove 7...Keep it! a Membrane 8...Organic medium conductor 9...Switch 11\Representative Patent Attorney/J% Kawakou Oshio Figure 1q Figure 2 7, Figure 3

Claims (1)

[Claims] 1. In a system for optically recording and reproducing information, the information recording section consists of two electrodes and a memory film provided between the electrodes, and the memory film can take two states with different optical constants. It is a substance that stores information by heating the information recording section and changing the optical constants of the memory from one state to another stable state.The change in optical constants allows the information to be optically reproduced and the information is stored. In erasing, the memory film was heated and a different electric field strength or heat was applied to both ends of the two electrodes than when information was stored, so that the memory film returned to its original stable state. An information storage carrier characterized by: