JPS621135A - Optical card information recording and reproducing device - Google Patents

Abstract

PURPOSE:To reproduce and erase exactly high density recording information without always depending on a tracking signal, by changing a spot shape of an irradiated light. CONSTITUTION:A photodetector 61 is provided with four split photodetecting sensors F1-F4, and detects a spot shape of an optical beam which is irradiated to a position of a point P of an optical card 2. For instance, in case of a spot of a true circle, it can be discriminated by constituting it in advance so as to become equal to each photodetecting quantity of the photodetecting sensors F1-F4, and by providing furthermore plural pieces of photodetecting sensors, a complicated spot shape can also be detected. An optical spot discriminating circuit 62 discriminates a shape of an optical spot which is photodetected by the photodetector 61, by detecting photodetecting quantities F1p-F4p of the photodetecting sensors F1-F4, by which a condition of an irradiated spot of the point P of the optical card 2 is known, although it is indirect. Also, when it is detected that the irradiated spot of the point P is not a necessary shape, a spot shape control output 63 is generated, and the constitution of an objective lens 8 is varied so as to conform to an object condition.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an information recording/reproducing device for an optical card device.
Compared to cWi tape and magnetic cards, it has higher density and more reliable characteristics.

[Background of the invention]

As information recording devices using magnetic tape, for example, tape recorders, VTRs (video tape recorders), and the like are known. These have the disadvantage that the amount of information recorded per unit area is smaller than that of optical discs.

Regarding information recording and reproducing devices using optical tapes, for example, Japanese Patent Application Laid-open No. 57-3347 and Japanese Patent Application Laid-open No. 58-6664 are known, but they do not require high-density recording or reliable alignment of the optical axis and recording point. Not all measures to improve performance are mentioned.

In other words, it is known that the optical recording method can improve the recording density by about 100 times compared to the magnetic recording method, but the high reliability when recording and reproducing information at intervals of about 1 to 2 μm is Improvements in technology are desired.

By the way, as an example of adopting the optical recording method, there is a nine optical disk device described in the August 1984 issue of the magazine [Hitachi Hyoron J, etc.].

In order to ensure high-density recording and reproduction, this optical disc is equipped with a means for aligning the optical axis of the light irradiation with the recording medium using a guide signal called tracking.

However, in order to perform accurate tracking, the structure of the device must become more sophisticated, leading to an increase in the size of the device.

[Purpose of the invention]

The present invention does not necessarily rely on tracking signals;
The objective is to accurately reproduce and erase high-density recorded information.

[Summary of the invention]

In the present invention, the information recording, reproducing, and erasing functions of an optical card can be performed by changing the spot shape of the irradiated light without controlling the optical axis using a tracking signal.

[Embodiments of the invention]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention. The symbols shown in the figure and their operations will be explained below.

Reference numeral 1 denotes an optical system for irradiating a light beam onto an optical card having a recording medium.

2 is an optical card to which a recording medium is added.

3 is a light source that uses, for example, a semiconductor laser diode. By accessing information to the optical card 2, the semiconductor laser diode allows the output of the light source 1 to be manipulated for recording, reproducing, or erasing information.

SWw is a switch that is closed during recording, SWm is a switch that is closed during playback, and SWm is a switch that is closed when 5Wxl'l is erased.

By closing any of the switches S Ww , S WR or SWz, the optical output and wavelength of the optical light source 1 are determined according to its intended function, and the output light P of the light source 1 is
yields 3.

At the same time, the optical card 2 also sends a signal to a symbol 81, which will be explained later, as an operation signal for controlling the shape of the irradiated light beam spot.

It is a 4-point collimating lens. The collimating lens 4 is
It is for outputting the input light P as parallel light, and the parallel light is indicated by the symbol P4.

It is a 5-piece reflective mirror, which is used to refract the input light beam P4 in the desired direction, and its output light is designated by the symbol P!
Indicated by

6 is a polarizing beam splitter. The polarized beam splitter 6f'1 is caused to pass through the human-powered light P, and its output light is designated as P8. Also, the light ray P6 that returned from the output side? Output light 6? reflect in the direction of.

Reference numeral 7 denotes a quarter wavelength plate, which shifts the phase of the wavelength of light passing through it. Let the output light be P.

8 is an objective lens. 8 objective lenses, input light P, and gold tip are used to connect a required spot shape to the desired position fiP of the optical card.

Let P be the output light of the objective lens 8.

The wavelength of the light source and the switch SWw in order to properly focus the necessary amount of light for the purpose of illumination.

The position and configuration of the objective lens 8 are varied depending on whether S Wll or S Wz is closed.

8W is a lens drive unit for varying the configuration and position of the objective lens.

Reference numeral 811 denotes a control circuit for transmitting a lens drive unit 8WVc restraint command 8WS.

Control circuit 81rri switch S Ww , S 'iV
i, 8 Wz closed circuit conditions, and the reflected light from the irradiation light position P of the optical card 2 is detected by the light beam pao through the objective lens 8, the quarter wavelength plate 7, and the polarizing beam splitter 6, and the control command 8Ws is generated. Determine.

61 is a photodetector. The photodetector 61 is divided into four photodetection sensors i;', , F2. F', , F4 are provided, and the shape of the light beam spot irradiated onto the position of point P on the optical card 2 is detected. For example, in the case of a perfect circular spot, the light detection sensors Ft, Ft, Fs, F4
Identification is possible by making the amount of received light equal to any one of the amounts.

Furthermore, by providing a plurality of photodetection sensors, even complex spot shapes can be detected.

62 is a light spot discrimination circuit.

The light spot discrimination circuit determines the shape of the light spot received by the photodetector 61 using the light detection sensors F, , F, .

Fs, amount of light received at F4 L PT Fop I Fsp
By detecting t F4p , the conditions of the irradiation spot at point P on the optical card 2 can be determined, albeit indirectly.

When it is detected that the irradiation spot at points te and P does not have the desired shape, vc generates a spot shape control output 63 and changes the configuration of the objective lens 8 to meet the desired conditions.

Further, 5WS is a reflection mirror control signal for adjusting the reflection angle of the reflection mirror 50 so that the light spot is irradiated in the intended direction.

The reflection mirror control signal 5WS is sent to the optical spot discrimination circuit 62T.
It is given by /c.

5W is a reflection mirror drive unit for adjusting the reflection angle of the reflection mirror 50.

These are the information output signals of the 20 optical cards 2, for example, the amount of light received by the photodetection sensors Fr, Fs, Fs, F4, F1 p, F2p, 'Fsp e Fap.
This can also be done by detecting the composite value of , using a light spot determination circuit.

This is an example of the structure of a folder on which the 9IIi optical card 2 is placed, viewed from the front.

10 is a position P where the optical card 2 is irradiated with a light beam spot.
This is an optical card drive device that moves the relative position of the optical system 1 in order to vary the optical system.

11fl, 6 on the ninth slide to move folder-9
Ru.

The optical card drive device 10 and the slide IIK allow the optical card 2 placed on the folder 9 to be moved, for example, from the back of the drawing to the front (back and forth).

Further, when one scanning is completed, K moves the folder 9 to either the left or right side of the figure, and also moves in the front and rear directions in the same way as above, thereby recording the information on the plane of the optical card 2. Can access functions for recording, reproducing, and erasing information on a medium.

FIG. 2 is a conceptual diagram as seen from the surface of the optical card'.

2 shows a part of the optical card.

Pzu erasing light beam spot, PmH playback-beam sub-light beam spot of Pg-U recording signal, indicating information "mark", for example.

Psg is a light beam spot of a recording signal, and is an example of a binary signal indicating information "space".

At the time of playback, it is only necessary to be able to reliably identify Pswa and Pan.

Pw is the center line of the signal group.

2 indicates the direction of movement in the front and back direction, as shown in FIG. 1, in order to process the information on the optical card 2.

Finally, in the present invention, the information Ps□Pss is the area of circular spots with a diameter of about 1 μm, and the intervals between them are also about the same.

However, it is quite conceivable that the optical card 2 causes a surface wobble in the direction perpendicular to the moving direction V.

For this reason, it is possible to adjust by tracking control so that the center line PN VC irradiation light beam spot hits, but for this purpose, the VC should be written with a tracking signal, and a detection control circuit should be added. It is clear that the equipment becomes more complex.

In the present invention, a light beam spot elongated in a direction perpendicular to the moving direction V of the single-optical card 2 is used for recording. Examples of recording pits of information signal No. 3 by this recording light beam spot are symbols P+u and Pan.

The P+++i#2 information signal is a binary signal indicating "space" as Pc and t: as "mark". PR is a light beam spot when reproducing information, and is smaller than the information recording signals Fag and Psm mentioned above.
Even if the center of the light spot from the optical system 1 shown in FIG. 1 deviates from the information signal recording center line PN of FIG. The optical spot PR is the information recording signal P'ss and Ps+m (P's+m).
If PR exists, a reliable signal reproduction function can be achieved.

Further, FIG. 3 shows a plurality of recording lines Pyl, PNI...P by irradiating the optical card 2 with a plurality of light beam spots.
This is an example of obtaining ptpt.

The subscripts 1.2...N indicate the order of the center lines of the recording lines, and Psm, P8S, PR, and Pztn indicate the equivalents to those in FIG. 2, respectively.

As a means for irradiating a plurality of light beam spots, a plurality of light sources 1 shown in FIG. 1 may be used, but as a multi-head, for example, the objective lens 8 can be made into a multi-beam, and as shown in FIG. - Signals may be recorded, reproduced, and erased on the PNN line at the same time.

Furthermore, the recording density can be increased by shifting the positions of the light sources that irradiate PNI, P town, and Pwy as shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, high-density information recording and reproduction is possible, and information can be easily reproduced and erased even when the surface of the optical card is shaken.

[Brief explanation of drawings]

FIG. 1 shows an overall configuration diagram of the implementation of the present invention, FIG. 2 shows an embodiment of a light beam spot according to the invention, and FIG. 3 shows another embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Light source, 2... Optical card, 8... Objective lens, 9... Folder, 10... Optical card drive device. 'ρ ga, A,, yo+, 7□1,11 ika
゛、ri」rate 2 figure 3 figure r←

Claims (1)

[Claims] 1. In a device that records information by irradiating electromagnetic waves such as a light beam onto a recording medium, and reproduces or erases information, an optical card containing a recording medium in a card shape is used, and the optical card is An optical card information recording and reproducing device characterized by comprising means for changing the spot shape of an irradiated light beam according to an intended function. 2. The optical card information recording and reproducing apparatus according to the above item, characterized in that the reproducing light beam spot is made smaller than the size of the recording pit of the information signal. 3. The optical card information recording and reproducing apparatus according to the preceding item, characterized in that the recording pit erasing means for the information signal irradiates a light beam spot having an area larger than the recording pit. 4. An optical card information recording/reproducing device according to the preceding item, characterized in that the recording pit is elongated into a component perpendicular to the moving direction of the optical card. 5. The optical card information recording and reproducing device according to item 1, characterized in that a substance that undergoes a phase transition from crystal to crystal is used as the recording medium. 6. The optical card information recording and reproducing device according to item 1, characterized in that a material that undergoes a phase transition between crystalline and amorphous states is used as the recording medium. 7. The optical card information recording and reproducing device according to item 1, characterized in that a tracking signal is not used in either recording, erasing, or reproducing a signal.