JPS6220151A - Optical memory card - Google Patents

Abstract

PURPOSE:To attain high density recording by using a snaking path as a guide groove for recording the information. CONSTITUTION:The optical head is set onto a guide groove 21 for the induction to a prescribed guide groove 22 for recording the information. The interval of the branched guide path in the optical memory card is 50mum at the card edge, the interval with an adjoining guide groove 21 for the induction is about 0.5mm, and therefore, only by the mechanical shifting, the optical head can be positioned between branched guide paths. The guide groove 21 for recording the information snakes linearly, the pitch is 20mum, the amplitude is 0.5mm, the curvature of about the radius 1mum is given to the guide groove of the part in which the right and left shifting by the tracking is inverted, the following-up by the tracking function can be executed and the inversion of the right and left shifting can be also smoothly executed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an optical memory card, and is useful when recording and reproducing information using a light beam.

Conventional technology Conventionally, this type of optical memory card.

For example, there is something called "La5er Card J (trade name)".For details, see 1.

Proceedings of 5PIE Vat 3
29 P. 61-68.

The structure of an optical memory card according to this prior art is shown in FIG. 3. In FIG. J, 11 is a transparent substrate, 12 is a recording thin film, 13 is an underlayer for improving the recording sensitivity of the recording thin film 12, and 14 is a protective layer for the recording thin film 12 and the underlayer 13.

Reference numeral 15 indicates a laser beam for reproducing the notes 811, and reference numeral 16 indicates recorded bits.

The manner of recording and reproducing on this optical memory card will be described below.

First, information is recorded by irradiating a focused laser beam 15 through a transparent substrate 11 to melt and evaporate the recording thin film 12.
I'll go there on the 7th. The formation of the 16 bit rows is carried out by blinking the laser beam 15 while moving the optical system including the objective lens. Pip adjacent to the grain) 16
To form a row, the optical system is moved by the distance of the 16-bit row, and then the same operation is repeated.

The recorded information is reproduced by weakening the output of the laser beam 15 to an extent that the recording thin film 12 does not melt and reading the change in the amount of reflected light due to the bits 1-16 along the bit 16 column.

<Problems to be Solved by the Invention> By the way, in the reproduction of the optical memory card according to the above-mentioned prior art, the positioning of the 16 bit row in the optical system is done by moving the optical system to the same position as when recording. I'll do it though.

Since this is done only by mechanical movement and does not have a control mechanism using the reflected light from bit 16 during recording, it is difficult to insert or eject the optical memory card. This may be caused by misalignment of the optical system setting position force, etc.

The irradiation position of the light beam of laser light 15 is bit 16 column 1
If the signal is shifted, the signal may not be reproduced, or the signal in the adjacent 16 column may be detected. Therefore, the size of the pits 16 and the interval between the pits 16 cannot be made very small. That is, the size of bit 16 is 10 μm, and the interval between bit 16 rows is 50 μm.
The lower limit is around μm.

The recording density is approximately 5XlO bits for a card the size of a business card.

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, an object of the present invention is to provide an optical memory card 8 that can stably perform recording and reproducing operations and can achieve high recording density.

Means for Solving Problems> The structure of the present invention to achieve the above object is such that information is recorded and reproduced along a guide groove in an optical memory card in which a recording thin film is formed on a card-like transparent substrate. A meandering guide groove is formed on the transparent substrate.

Function> In the above-mentioned optical memory card, information is recorded and reproduced while tracking control is applied along the meandering guide groove. Also, to compensate for the decrease in recording density due to the increase in track spacing determined by the groove spacing required for the guiding grooves.

Information recording guide? By making II a meandering path.

The effective length of the guide groove is increased.

Example of implementation Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory view showing the structure of the optical memory card of this embodiment, and FIG. 2 is an enlarged view showing its cross-sectional structure. In both figures, 21 is a guide groove for guidance, 22 is a guide groove for information recording, 23 is a transparent substrate, 24 is a recording thin film, 25 is a heat insulating layer for improving the recording sensitivity of the recording thin film 24, and 26 is a recording layer. It is a protective layer for the thin film 24 and the heat insulating layer 25.

A method for manufacturing an optical memory card will be described below.

This manufacturing method is similar to that of conventional optical discs. That is, first, guide grooves 21 and 22 are formed on a glass plate using photoresist, and a groove original is produced. To comment further, after coating the photoresist on the glass plate with a spin cord, the guide grooves of the photoresist are formed! 8. Expose with a focused laser beam. By developing this, guide grooves 21 and 22 can be formed, and a groove original plate is produced. Next, after depositing silver or nickel for electrodes on this grooved master plate, a stamper is produced by nickel electroforming. Next, using this stamper, injection molding is performed on a plastic material such as acrylic resin using 2P (photo polymer).
A transparent substrate 23 of an optical memory card is obtained by transferring the grooves by a method such as a method. Next, a recording thin film 24 made of Te or a Te compound or the like is formed. Finally, a heat insulating layer 2 made of materials 1 with low light absorption and low thermal conductivity such as C5, etc.
5 and a protective layer 26 made of a plastic material such as acrylic photocurable resin.

Next, the manner of recording and reproducing information using the optical memory card of this embodiment will be described. Recording and reproducing information on this optical memory card is similar to recording and reproducing information on conventional optical discs.
Similar to reproduction, focus control and track control are performed by force using an optical head using a semiconductor laser.

In both recording and playback, when the optical memory card is inserted, the optical head moves to the predetermined information recording guide 5.
! Set it on top of the 2nd guide groove for guiding to 22. The distance between the branched guide paths in the optical memory card of this embodiment is 50 μm at the card end, and the distance between the adjacent guide groove 21 is about 0.5 μm, so the optical head can be branched with only one mechanical movement. It is possible to position the guideway between the guideways. Next, when the focus control and track control are turned on and the optical head is simultaneously moved in a direction parallel to the guide groove 21 for guidance, the optical head is tracked by the guide groove 21 for guidance, and then moves to the predetermined position for recording information. guide groove 22. Further, when the optical head is moved in a direction parallel to the guide groove 21 for guidance, the head moves left and right on the two meandering guide grooves due to the tracking function. The guide groove 21 for information recording is meandering in a linear shape, the pitch is 20 μm, the amplitude is 0.5 m, and the guide groove 21 has a radius of about 1 μm in the part where the left and right movement due to tracking is reversed. Since it has a curvature, it can be followed by a tracking function, and the reversal of left and right movement is also performed smoothly. The tracking operation described above is performed by weakening the output of the laser beam to such an extent that the recording thin film 24 does not melt, as in the reproduction described later.

Next, during recording, the output of the laser beam is increased in a pulsed manner according to the recording signal while tracking the information recording guide groove 22 to form a recording thin film 241. In the case of reproduction, while moving the optical head using the guide groove 22, changes in the amount of reflected light due to the bits are read. Since the information recording guide 22 of the optical memory card of this embodiment is a linear meandering path, the distance between the grooves becomes narrow near the apex of the guide groove where the left and right movement of the head is reversed. As you can see, in this part.

Since the radius of curvature is about 1/7fi, the distance between the closest grooves is more than 2μ, and there is almost no crosstalk.

Next, when moving to another recording guide groove 22 for recording/reproduction, the optical head is first moved onto the guide groove 21 for guiding to the predetermined information recording guide groove 22, and then Repeat the above action.

Next, more specific embodiments of the present invention will be described. After coating a glass plate with a spin code Nyoshifodresist, it is exposed to focused argon laser light and developed to form 1 width 0.6ptn depth 700X (7) guide groove 21
．． 22% formed. One information recording guide groove 22 has a pitch of 20 pm and an amplitude of 0.5 wm. (7) Meandering path and Ll,
100 guide grooves 22 were formed in one card. Next, nickel was vacuum-deposited on this grooved master plate, and then a nickel electroformed stamp was produced. Next, by injection molding, the grooves were transferred to the polycarbonate substrate, and a 90wx
A business card-sized transparent substrate 23 with a length of 855 m was produced. Next, record? After forming a C82 Te thin film as the 4 film 24 to a thickness of J400X by plasma polymerization method, a C8! A thin film was formed to a thickness of 2000× by plasma polymerization. Roughly, an epoxy-based photocurable resin was formed to a thickness of 30 μm as the protective layer 26 . When the optical memory card obtained by applying force 1 was attached to a recording/reproducing device using a semiconductor laser and a tracking experiment was attempted, after the optical head tracked the guiding guide 11121,
It was confirmed that tracking was performed reliably in the predetermined recording guide groove 22. The time required for tracking was less than 1 second, and the operation was stable even when inserting and removing cards. Next, when an attempt was made to record a signal onto the recording guide groove 22, a bit with a diameter of about 1 pm was formed on the card at a laser power of 6 mW and a pulse width of 100 n1ce, which was completed on the optical memory card of this embodiment. It was confirmed that 2×10 bits of information can be recorded. moreover.

When trying to record and reproduce the code information, the tracking operation and the recording-reproduction operation were confirmed in the guide groove 22, and a reproduction signal of good quality was obtained. <Effects of the Invention> As explained above. 5. According to the optical memo IJ-card of the present invention, information can be recorded and reproduced while tracking along the guide groove.

If access is easy, it does not require a single force, and since the guide groove for information recording is a meandering path, there is an advantage that high-speed recording is possible.

[Brief explanation of the drawing]

Figure m1 is an explanatory diagram showing the structure of an optical memory card according to an embodiment of the present invention, Figure 2 is an enlarged cross-sectional view showing its cross-sectional structure, and Figure 3 is a partial cross-section showing the structure of an optical memory card according to the prior art. It is a diagram. Inside the drawing. 21 is a guide groove for guidance. 22 is a guide groove for recording information. 23 is a transparent substrate. 24 is record book 1x. 25 is a heat insulating layer, and 26 is a protective layer.

Claims (1)

[Claims] An optical memory card in which a recording thin film is formed on a card-like transparent substrate, characterized in that a meandering guide groove is formed on the transparent substrate so that information can be recorded and reproduced along the guide groove.