JPH031732B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] Laser light is irradiated onto a polymeric material film whose molecules have been oriented by stretch molding to locally relax the molecular orientation and record an information signal. as changes in reflectance, refractive index, and birefringence.
The present invention relates to an information recording memory that reproduces information using at least one of diffraction and interference effects.

[Prior art and its problems]

It is known that certain polymeric material sheets can be polarized by the action of temperature and electric field to exhibit pyroelectricity and piezoelectricity, and that this polarization occurs only at locations where both temperature and electric field act; Alternatively, if an electric field in the opposite direction 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. The information signal is stored as a locally different polarization distribution on the surface of the polymer 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. 47-41722. The fact that the polarization signal has pyroelectricity and piezoelectricity has the advantage that not only the pyroelectric method but also the piezoelectric method can be used as a signal regeneration method. In the case of reproduction using tension, the piezoelectric effect caused by changes in tension 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 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 simultaneously, they may cancel out completely. Furthermore, piezoelectricity having the same sign as the heating pyroelectricity generated by tension relaxation becomes a noise signal.
Furthermore, other polymeric materials include lead titanate,
When polarizing a composite piezoelectric material made by mixing barium titanate, lead titanium zirconate, and other ferroelectric inorganic compound powders with thermoplastic resin, the polarity of the piezoelectricity caused by applying tension and the pyroelectricity generated by heating are in the same direction. Therefore, polymer materials containing a large amount of ferroelectric powder often have the same polarity, but in this case, piezoelectricity and pyroelectricity can occur if tension reduction and heating occur simultaneously. cancel each other out.
The most common method for recording and reproducing information using a sheet-like recording material is a method in which a tape-like recording material is wound onto a reel and recorded or reproduced while being wound onto another reel. However, when running the tape while rewinding it, tension is always applied, and it varies greatly depending on the start and stop of running, changes in speed, etc. 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 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, information recording memories that record locally different distributions of polarization on a polymeric material sheet and read the recorded polarization signals by reproducing them pyroelectrically or piezoelectrically have problems during reproduction. The disadvantage of this method is that its resolution is largely dependent on the resolution of the read 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 uniformly electrified in advance with a light beam was also developed in 1973.
36298, and is well known as a high-density recording method. However, even in this case, readout requires a needle-like inductive electrode that detects the external electric field, or
It uses MOS type semiconductor field effect elements, etc.
There were major restrictions on high-density recording and recording speed.

[Objective of the Invention] The present invention involves irradiating an information signal with a laser beam onto a polymeric material film whose molecules are oriented by stretching.
Information recording in which the molecular orientation is locally relaxed and recorded, and the recorded signal is reproduced as changes in reflectance, refractive index, and birefringence using at least one of polarization, diffraction, and interference effects. The purpose is to provide memory. For more details, conventionally,
This is an improvement over the significant delay in high-density, high-speed recording and reproduction, and aims to perform recording and reproduction optically.

[Summary of the Invention] The present invention provides molecularly oriented polyethylene, polystyrene, polypropylene, and other polyolefins, polyvinyl ketones, polyethers, fluororesins, polycarbonates, polyesters, polyamides, diene plastics, polyamides, polysulfones, polycarbonates, etc., which are molecularly oriented by stretch molding. Laser light is irradiated onto a stretch-molded polymer material film made of at least one of enylene sulfide, high acrylonitrile copolymer and derivatives thereof, and cellulose plastic, and optical properties of the irradiated portion of the film are determined. That is, this is an information recording method characterized by recording locally by relaxing the molecular orientation caused by stretching, and reading this optically.

[Effect of the invention] Since information is written by irradiating laser light onto a polymer material film stretched uniaxially or biaxially, and information is read by irradiating laser light, high-speed and It has the advantage that high-density, fine patterns can be read and written easily. It also has the advantage of being able to record and reproduce both reflection and transmission.

[Embodiments of the Invention] FIG. 1 shows a film of a polymeric material whose molecules are oriented by stretching according to the present invention, such as polyethylene, polystyrene, polypropylene and other polyolefins, acrylic resin, polyvinyl chloride, polyvinyl acetate, and polyimide. , polyvinyl ether, polyvinyl ketone, polyether, fluororesin, polycarbonate, polyester, polyamide, diene plastic, polyamide, polysulfon, polyphenylene sulfide, high acrylonitrile copolymer and derivatives thereof,
A polymeric material film 1 made of at least one cellulosic plastic is shown.

FIG. 2 is a block diagram for implementing recording and reproduction according to the present invention, in which 2 is a laser beam, 3 is a polarizer, and 4
5 is a polymer material film, 5 is an analyzer, and 6 is a detector. Polymer material films are generally formed by the inflation method or T-shaped die method.
The film may be formed by a solution casting method and then stretched, or may be formed by a calender method. The present inventor irradiated this polymer material film 4 with a laser beam 2 such as a carbon dioxide laser, a ruby laser, a helium neon laser, or a semiconductor laser through a polarizer 3, thereby forming molecules by stretching the portion irradiated with the laser beam. reflectance by relaxing orientation,
It has been found that the refractive index and birefringence can be changed.

FIG. 4 is a diagram showing output signals recorded and reproduced based on the present invention. In other words, as shown in Figure 3, a pattern corresponding to information can be written as a distribution of relaxation of molecular orientation that occurs during stretch forming, and this can be recorded as a distribution of relaxation of molecular orientation caused by stretch forming with less energy than the energy required for recording. We discovered that reproduction can be performed by reading out using a laser beam that does not cause relaxation.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the configuration of a polymer material film used to implement 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. A schematic diagram of an information recording memory formed by these, and FIG. 4 is a diagram showing reproduced signals. DESCRIPTION OF SYMBOLS 1, 4... Polymer material film, 2... Laser beam, 3... Polarizer, 5... Analyzer, 6... Laser beam irradiation part, 7... Detector.

Claims (1)

[Claims] 1. An information recording method characterized by recording an information signal by locally relaxing the molecular orientation caused by stretching of a recording layer made of a stretch-molded polymeric material film, thereby changing optical characteristics by locally relaxing the molecular orientation caused by stretching of a recording layer made of a stretch-molded polymer material film. .