JPS58155543A - Information recording memory - Google Patents

Abstract

PURPOSE:To enable the writing of a pattern at high speed and high density, by irradiating an uni- or biaxially stretched film of a vinyl halide polymer, a vinyl cyanide polymer or polyacrylonitrile with laser light. CONSTITUTION:A polymer film 4 is polyvinylidene fluoride film having about 80mum thickness obtd. by forming a film by a T die method, heating it to 105 deg.C, and stretching the heated film 5 times. By irradiating the film 4 with laser light through a polarizer 3, the reflectance, refractive index and double refractive index of the irradiated part are changed to enable writing. Readout is also enabled by detecting laser light passed through the film 4 with a photodetector 5. Thus, the writing of a pattern is enabled at high speed and high density.

Description

[Detailed Description of the Invention] [Technical Field to which the Invention Pertains] The present invention provides a method for producing different effects by irradiating a stretch-molded film made of a halogenated vinyl polymer, a cyanated vinyl polymer, or polyacrylonitrile as a substrate with loser light. The present invention relates to an information recording memory in which the recorded signal is recorded as a distribution of a crystal structure, and the recorded signal is reproduced and read using the interference effect of polarized light.

[Conventional technology and problems]

It is known that various kinds of polymeric material sheets are polarized by the action of temperature and electric field and have pyroelectricity and piezoelectricity. Furthermore, if an electric field in the direction opposite to the original polarization is applied to a local part of a polarized polymeric material sheet along with temperature, the polarization in that part will be erased or reversed. By utilizing the properties of edges, information signals are stored as locally different polarization distributions on the surface of a polymeric material sheet.
An information recording and reproducing method for reproducing and reading this information as necessary has already been proposed in Japanese Patent Laid-Open No. 47-417!2. The fact that the polarization signal has pyroelectricity and piezoelectricity has the advantage that not only a non-electroelectric method but also a piezoelectric method can be used to reproduce the signal. In the case of regeneration, the piezoelectric effect due to changes in the tension acting on C) may cause noise. When a sheet of polymeric material that can record information through polarization is polarized, the polarity of piezoelectricity generated when tension is applied to this sheet and the polarity of pyroelectricity generated when this sheet is heated are mutually exclusive. In the opposite direction, if heating and tension are applied at the same time, the effects of silkworms may be canceled out. Furthermore, piezoelectricity having the same sign as the heating pyroelectricity caused by tension relaxation causes a sharp noise signal.

Furthermore, when other polymeric materials such as lead titanate, barium titanate, lead titanium zirconate, and other ferroelectric inorganic compound powders are polarized, composite piezoelectric materials made by mixing powders of ferroelectric inorganic compounds with thermoplastic resins generate piezoelectricity due to the application of tension. The polarity of the pyroelectricity generated by heating is in the same direction, and therefore polymer materials containing a large amount of ferroelectric powder often have the same polarity. When these occur at the same time, piezoelectricity and pyroelectricity cancel each other out.

The most common method for recording and reproducing information using sheet-shaped recording material is a method in which tape-shaped recording material is wound onto a reel and recorded or reproduced while being re-wound onto other reels. However, when running the tape while rewinding the tape, the tension always changes greatly depending on whether the tape is turned on, starts running, stops, or changes speed. Furthermore, tension fluctuations also 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 variation in tension 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 differences in polarization between localized areas on the surface, the applied pressure must be applied perpendicularly to the sheet surface, but changes in the tension applied to the sheet are required. If there is, this tension variation will result in noise in the piezoelectric signal. Furthermore, in addition to the above-mentioned problems, an information recording memory that records locally different distributions of polarization on a polymeric material sheet and reproduces and reads the recorded polarization signals using pyroelectric or piezoelectric methods is a reproducing method. This method has the disadvantage that the resolution during reading largely depends on the resolution of the reading head, making it 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 published in Japanese Patent Publication No. 53-36198KF, and is well known as a high-density recording method. However, even in this case, readout requires a needle-shaped inductive electrode or an MO8 type semiconductor field effect element for detecting an externally appearing electric field, and there are significant restrictions on the high-density recording method and the recording speed.

[Purpose of the invention]

The present invention records information signals as locally different crystal structures by irradiating a laser beam onto a stretch-formed film made of ft-''logenated vinyl polymer, cyanated vinyl poly-1-, or bo-1-noacrylonitrile. The object of the present invention is to provide an information recording memory in which the recorded signal is reproduced by using the interference effect of polarized light as a change in reflectance, refractive index, and birefringence. It is intended to improve the large delay in recording, high-speed recording and reproduction, and is intended to perform recording and reproduction optically.

[Summary of the invention]

The present invention involves irradiating a stretch-molded film with a substrate of halogenated vinyl polymer, cyanated vinyl polymer, or polyacrylonitrile to record information signals as locally different crystal structures, and then An information recording memory that reproduces changes in reflectance, refractive index, and birefringence using the interference effect of polarized light.
More specifically, a laser beam is irradiated onto a polyvinylidene fluoride film in the β-crystal form with an infrared absorbance ratio of D530/D510 (1,2) that has been stretched in the -axis or biaxial direction, and the crystal structure of the irradiated area is changed to the α-crystal form. It is characterized by recording information by converting it, and reproducing the recorded signal using the interference effect of polarized light. This is an information recording memory with a high birefringence.

[Embodiments of the invention]

FIG. 1 represents a stretch-molded polymeric material film l based on a halogenated vinyl polymer, a cyanated vinyl polymer, or polyacrylonitrile as described in the present invention.

FIG. 2 is a block diagram for carrying out the recording and reproduction of the present invention, in which 2 is a laser beam, a 3Fi polarizer, 4 is a polymer material film, and 5 is an analyzer. Polymer material film is T
It is a polyvinylidene fluoride film with a thickness of 80 um, which was formed into a film by the die method, heated to 105°C, and stretched at a stretching ratio of 5 times, and has an infrared absorbance ratio of D53.
0/D510 is 008. The present inventor has irradiated the polymer material film 4 with laser light by irradiating the laser beam 2 such as carbon dioxide laser, ruby laser, helium neon laser, or semiconductor laser through the entire polarizer 3. It was discovered that changes in reflectance, refractive index, and birefringence can be caused only by the crystal structure of the part. After irradiation with laser light, the infrared absorbance ratio D53010510 of the irradiated area was 48. For reproduction, if the laser beam 2 that has passed through the polymeric material sheet 4 is incident on the analyzer 5, it is possible to read out the information by the interference effect of polarized light.

FIG. 3 is a schematic diagram of the information recording memory manufactured in this manner. Reference numeral 4 represents a polymer material film, and 6 represents a portion where the crystal structure has changed, that is, the optical properties have changed due to irradiation with laser light.

As shown in Figures t and b, the pattern corresponding to the information is the reflectance,
It can be written as a distribution of changes in refractive index and birefringence, and if this is optically read out with a laser beam, it can be used as an information storage memory.

〔Effect of the invention〕

As explained above, the present invention writes and reads information by irradiating a film with a substrate of halogenated vinyl polymer, cyanated vinyl poly 1-, or polyacrylonitrile that is stretched in a -axis or biaxial direction. Therefore, by controlling the laser beam, it is possible to easily write and read fine notches at high speed and with high density.

Therefore, information is written by irradiating a laser beam onto a polymer material film stretched in the −axis or biaxially.
Since information is read by irradiating laser light, it has the advantage that fine patterns can be easily written at high speed and with high density by controlling the laser light. Furthermore, it can be recorded and reproduced both by reflection and transmission, and the process of converting into electret can be omitted.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the structure of a polymeric material film used for 5iI# information recording memory of the present invention, and FIG.
The figure is a configuration diagram for implementing recording and playback of the present invention, WJ
FIG. 3 is a schematic diagram of an information recording memory formed by these. 1.4...Polymer material film, 2...
・Laser beam, 3...Polarizer, 5...
・Analyzer, 6...Laser light irradiation department representative
Patent Attorney Kensuke Chika (first name) Figure 1 Figure 2

Claims (2)

[Claims] (1) Stretch-molded halogenated vinyl poly 1-,
Laser light is irradiated onto a film with cyanated vinylimer or polyacrylonitrile as a substrate, and information signals are recorded as locally different crystal structures, and the recorded signals are converted into changes in reflectance, refractive index, and birefringence. , an information recording memory characterized by reproduction using the interference effect of polarized light. (2) The film is uniaxially or biaxially stretched polyvinylidene fluoride film with an infrared absorbance ratio of 1) 530/D510 (1,1!) and is irradiated with a laser beam. The crystal structure of the irradiated area is a
2. The information recording memory according to claim 1, wherein information is recorded by converting the crystal form of KR, and the recorded signal is reproduced by the interference effect of polarized light.