JPS58155544A - Information recording memory - Google Patents

Abstract

PURPOSE:To carry out reversible writing, by irradiating a polarizable polymer sheet polarized by polarizing operation with laser light. CONSTITUTION:A polarizable polymer film 1 of a vinyl halide polymer, a vinyl cyanide polymer or polyacrylonitrile on a metallic reflection film 2 is polarized by applying an electric field. When the polarized polymer film is irradiated with laser light, the polarization of the irradiated part is relaxed, so the reflectance, refractive index and double refractive index are changed to enable writing. In case of reproduction, the film 1 is irradiated with polarized laser light, and the reflected light is detected with a photodetector to enable readout. The polarization is erased by applying an electric field in the reverse direction. Thus, a reversible information recording memory is obtd.

Description

[Detailed Description of the Invention] [Technical Field to Which the Invention Pertains] The present invention provides a method of polarizing a polymeric material sheet that maintains pyroelectricity and piezoelectricity by irradiating it with laser light. The information recording memory C2 records information signals as changes in reflectance, refractive index, and birefringence, and optically reproduces and reads the recorded signals.

[Conventional technology and problems]

It is known that the polymeric material sheet that is used as a food material is polarized by the action of temperature and electric field, and has non-electroelectricity and piezoelectricity. Fi also takes advantage of the property that if an electric field in the opposite direction to the original polarization is applied to a local part of a polarized polymer sheet along with temperature, the polarization in that part will be erased or reversed. , the information signal is stored as a locally different polarization distribution on the surface of the polymeric material sheet.

An information recording and reproducing method for reproducing and reading this information according to the required scenery has been proposed in Japanese Patent Laid-Open No. 47-41722. The fact that the polarization signal has non-electricity and piezoelectricity has the advantage that not only pyroelectric method but also piezoelectric method can be used as a signal regeneration method. In the case of reproduction using the sheet, the piezoelectric effect caused by the change in tension g2 acting on the sheet may cause noise. When a sheet of polymeric material that can record information through polarization is polarized, the polarity of piezoelectricity produced when tension is applied to this sheet, and the polarity of pyroelectricity produced when this sheet is heated. are in opposite directions, and if heating and tension are applied simultaneously, they may cancel each other out. Furthermore, piezoelectricity having the same sign as the heating pyroelectricity generated by tension relaxation becomes a noise signal.

History 62 When a composite piezoelectric material made by mixing other polymeric materials such as lead titanate, barium titanate, titanium zirconium lead, and other ferroelectric inorganic compound powders with thermoplastic resin is polarized, it is possible to polarize it by applying tension. The polarities of piezoelectricity and pyroelectricity generated from heating are in the same direction, and therefore polymer materials containing a large amount of ferroelectric powder often have the same polarity, but in this case, the tension decreases. When heating and piezoelectricity occur at the same time, piezoelectricity and pyroelectricity cancel each other out.

The most common method for recording and reproducing information using sheet-like recording material is a method in which tape-like recording material is wound onto a reel and recorded or reproduced while being re-wound onto another reel. However, when running the tape while rewinding it, tension is always applied, and changes such as the start and stop of running, or changes in speed, etc., vary more than g2.

Furthermore, tension fluctuations occur if the reel operation is even slightly unsmooth, and the fluctuations in this case are often caused by repetitive vibrations. If the piezoelectricity caused by this tension variation C2 has the same polarity as the pyroelectricity caused by information reproduction, it becomes a noise signal, and in the opposite case, the information is canceled out, resulting in an erroneous signal. Furthermore, even when information is reproduced piezoelectrically, in order to see the difference in polarization between local areas on the surface, the applied pressure must act in the vertical direction C2 on the sheet surface, but the tension applied to the sheet If there is a fluctuation in the tension, this fluctuation in tension becomes noise in the piezoelectric signal. In addition to the above-mentioned problems, polymer material sheets can be recorded as locally different polarization distributions, and the recorded polarization signals can be electroless or piezoelectric.
Information recording memories that are replayed and read have the disadvantage that the resolution during reproduction largely depends on the resolution of the read head, and is therefore unsuitable for high-density recording.

On the other hand, an information recording memory in which information is written by irradiating a polymer material film that has been uniformly electretized in advance with a light beam is also described in Japanese Patent Publication No. 53-36298, and is well known as a high-density recording method. However, even in this case, readout uses needle-shaped inductive electrodes that detect the electric field appearing externally, or MOB-type medium-conductor field-effect elements, which is subject to significant restrictions on high-density recording and recording speed. was.

[Purpose of the invention]

The present invention involves polarization operation - by irradiating a sheet of a polarizable polymer material with spontaneous polarization with laser light, a difference in polarizability is formed locally to record information, and the recorded signal is reflected by the reflectance. The purpose is to provide an information recording memory that is optically reproduced as changes in refractive index and birefringence. It is an object of the present invention to provide a novel information recording memory which is improved in the above points and further performs optical recording and reproduction using a polarizable polymer material sheet having spontaneous polarization.

[Summary of the invention]

By irradiating a pre-polarized polarizable polymer material sheet with spontaneous polarization by a polarization operation with a laser beam, a local I: difference in polarizability is formed and an emotional signal is recorded; This is an information recording memory characterized by optically reproducing recorded signals.

〔Effect of the invention〕

According to the present invention, information is written by irradiating a polarizable polymer material film that can maintain spontaneous polarization by polarization operation, and information is read by irradiating the laser beam. Easy control to read and write fine patterns at high speed and high density! It has the advantage of being able to do two things. In addition, recording is done using both reflection and transmission methods.
Can be played. Another advantage is that reversible information recording is possible by repeating the polarization operation and laser beam irradiation.

[Embodiments of the invention]

FIG. 1 shows a polarizable polymer material film 1 capable of retaining more spontaneous polarization according to the polarization operation I according to the present invention, which uses, for example, halogenated vinyl polymer, cyanated vinyl polymer, or polyacrylonitrile as a substrate. The film surface C2 is of a reflective type, and a metal reflective film 2 for reading is provided on the surface opposite to the incident optical path (FIG. 1(a)). A transparent electrode 3 may be provided on the film surface on the incident optical path side (
Figure 1 (b)).

In order to read out a transmissive type, there are two cases: no electrodes are provided on the surface (Fig. 1 (C)), and cases where at least two transparent electrodes are provided on one surface (Fig. 1 (a)). is a configuration diagram for carrying out the recording and recording of the present invention, 4 is a laser light source, 5Fi laser beam, 6Fi polarizer, 7#i polarizable polymer film, 8 is an analyzer, and 9 is a detector. and indicates the transparent type [7]. Polarizable polymer film is formed by T-die method S: at 105°C.
5 times the heating state: Stretched infrared absorbance ratio D
It is polyvinylidene fluoride with a thickness of 80 μm and a 6-concavity/coffin ratio of 0.08. The present inventor has developed a polymer material film that can maintain spontaneous polarization through this polarization operation -1 Carbon dioxide laser, ruby laser, helium neon laser -
Alternatively, it has been found that by irradiating a laser beam 5 such as a semiconductor laser through a polarizer 6, the polarization of the irradiated part of the laser beam 5 is relaxed, causing changes in reflectance, refractive index, and birefringence ≦. If the laser beam 5 passed through the polarizable polymer material sheet 7 is incident on the analyzer 8C, it is possible to read it by the interference effect of polarized light.

FIG. 3 is a schematic diagram of an information recording memory manufactured in this manner. 7 polarizable polymer material film, 10
Laser light 1: represents a portion where a change in polarizability, that is, a change in optical characteristics occurs upon irradiation. As shown in Figure 10, the information corresponds to nine (turns on reflectance, refractive index,!
! ! It can be recorded as a distribution of changes in refractive index, and if this is read out using a laser beam, it can be used as an information recording memory.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the configuration of a polymer material film used for implementing the information recording memory of the present invention, FIG. 2 is a configuration diagram for implementing recording and reproduction of the present invention, and FIG. This is a schematic diagram of an information recording memory formed by S: FIG. 1.7...Polarizable molecular material film 2--Metal reflective B S--Transparent electrode 4--Laser light source 5
... Laser beam 6 - Polarizer 8 - Analyzer 9 - Detector 10 - Portion whose polarizability changes when irradiated with laser light (
7317) Representative Patent Attorney Kensuke Chika (and 1 other person) 1st cause Figure 2, 7

Claims (2)

[Claims] (1) By irradiating a polarizable polymer material sheet that has spontaneous polarization with a laser beam through a polarization operation, an information signal is recorded locally as two different polarizations, and the recorded signal laser beam is used to optically An information recorder that is characterized by being played back. (2) The polarizable simple molecule material sheet is a polarizable polymer material sheet whose non-electricity and piezoelectricity are maintained by polarization operation, and by irradiating this sheet with laser light,
By locally depolarizing or releasing oriented areas, a unique polarization pattern is formed to record information, and the recorded signal is optically reproduced using laser light. Information recording memory 0 according to claim 1, characterized in that: