JPH0582659B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an optical information recording and reproducing method, and particularly to a method for recording information on a card-shaped optical information recording medium provided with a track for obtaining a tracking signal and a clock signal. , and also relates to an optical information reproducing method for reading recorded information.

[Prior art]

2. Description of the Related Art Conventionally, various types of media such as disks, cards, and tapes have been known as media for recording information using light and for reading recorded information.
Among these, card-shaped optical recording media (hereinafter referred to as optical cards) are expected to be in great demand as small, lightweight, easily portable media with a large storage capacity.

By the way, the above-mentioned optical card uses a light beam that is modulated according to recorded information and focused on a minute spot.
By scanning the card, information is recorded as an optically detectable row of recorded pits (information track). At this time, in order to record information accurately without causing troubles such as crossing of information tracks, the irradiation position of the crossing beam is controlled in a direction perpendicular to the scanning direction (auto tracking, hereinafter referred to as AT). It was necessary to do so. Furthermore, in order to correct fluctuations in scanning speed, it was necessary to obtain a clock signal during recording. Therefore, the applicant has decided to hire Drexler Technology Co., Ltd.
According to a technical disclosure received from J.D. Corporation, an optical card has been proposed in which a track for obtaining a tracking signal and a clock signal is formed on the card in advance. A first example of such an optical card is shown in FIG.

FIG. 9A is a schematic plan view of the optical card. Here, a clock signal is recorded in advance on the optical card 31, and clock tracks 32 ₁ , 32 ₂ , 32 ₃ , 32 ₄ , . . . formed in the form of intermittent broken lines are arranged at equal intervals. There is. Between the clock tracks, there is a storage area 34 ₁ for recording information,
34 ₂ , 34 ₃ , . . . are provided.

FIG. 9B shows an enlarged view of the recording surface of the optical card 31. When recording information on this optical card, three beams are emitted from the optical head, and each beam is focused into minute spots S ₁ , S ₂ , and S ₃ . These spots are scanned in the direction of arrow a by the relative movement of the optical card and the optical head, and information is stored in the recording area ₃₄₁ as in the recording pit 35 by the center spot _S2 . recorded. Further, the reflected light from either spot _S1 or _S3 is guided to a detection means within the optical head assembly, and a tracking signal is detected using a well-known method such as a so-called push-pull method. Based on this tracking signal, the positions of spots S ₁ , S ₂ , and S ₃ in the direction perpendicular to the scanning direction (b direction) are moved together so that spot S ₁ always accurately traces the clock track 32 ₁ . Control as follows. Therefore, the recording bits 35 are formed accurately along the clock track ₃₂₁ , and crossing of the information tracks can be prevented. At the same time, spot
A clock signal is reproduced from the reflected light from _S1 or _S3 and is used as a clock for the recording signal. Furthermore, information is reproduced in the same manner.

However, in optical cards, the transfer speed of the card during recording or playback is generally slow, so the frequency of fluctuations in the tracking signal due to the discontinuity of the clock track is close to the servo band of the AT, which has the disadvantage of adversely affecting the AT. It was hot.

Therefore, a second example of an optical card that solves the above drawbacks is proposed in the above-mentioned technical disclosure. This is shown in FIG. FIG. 10A is a plan view, in which the optical card ₄₁ has recording areas 44 ₁ , 44 ₂ , .
42 ₂ , 42 ₃ , . . . and tracking tracks 43 ₁ , 43 ₂ , 43 ₃ , . . . are formed on the other side, respectively. Here, the tracking tracks 43 ₁ , . . . have a continuous linear form.

FIG. 10B shows an enlarged view of the recording surface of the optical card 41. This optical card basically has three spots scanned in the direction of arrow a, similar to the example shown in FIG.
A recording pit 45 is recorded by spot _S2 .
However, in this example, the tracking signal is obtained by tracing the tracking tracks 43 ₁ , 43 ₂ , . . . at spot S ₃ . Further, the clock signal is obtained from the spot S ₁ which is illuminated on the clock tracks 42 ₁ , 42 ₂ , . Therefore, in this example, the tracking signal can be detected completely independently of the clock signal, allowing accurate AT.

However, compared to the example shown in FIG. 9, the optical card 41 requires a larger area for providing tracking tracks, and the recording capacity per area cannot be avoided.

[Summary of the invention]

The purpose of the present invention is to solve the drawbacks of the prior art by using an optical card with a new configuration, to record high-density information while performing accurate AT, and to record information with high density while performing accurate AT. An object of the present invention is to provide an optical information recording and reproducing method that allows information to be read out at high speed.

The above-mentioned object of the present invention is to provide a plurality of continuous linear tracking tracks, each of which generates a tracking signal, and a plurality of intermittent broken lines, each of which is arranged alternately with the tracking tracks and generates a clock signal. a clock track, and a recording area for recording information arranged between each of the tracks, and between the two adjacent recording areas, there is no space between the tracking track or the clock track. In an optical information recording/reproducing method for a card-shaped recording medium, which records or reproduces information on a card-shaped optical information recording medium characterized in that only one track is arranged, the medium is irradiated with light. (a) one of the second and third beams scans a tracking track to detect a tracking signal; a recording step of recording information by scanning the recording area with the first beam while detecting a clock signal by scanning the clock track with the beam; (b) scanning the tracking track with the first beam; While scanning and detecting a tracking signal, the second and third beams simultaneously reproduce information from recording areas disposed on both sides of the tracking track being scanned by the first beam. This is achieved by an optical information recording and reproducing method for a card-shaped recording medium, which is characterized in that recording or reproducing is performed by a reproducing step.

〔Example〕

FIG. 1 is a schematic plan view of an optical card used in the method of the present invention. In the figure, clock signals are recorded in advance on the optical card 1, and clock tracks 2 ₁ , 2 ₂ , 2 ₃ , . . . are formed in the form of intermittent broken lines.
and tracking tracks 3 ₁ , 3 ₂ , . . . formed in a continuous linear shape are alternately arranged at equal intervals. Recording areas 4 ₁ , 4 ₂ , 4 ₃ , . . . are provided for recording information between each track. That is, the optical card 1 has a recording area in the entire area between the clock track and the tracking track.

2 and 3 are diagrams illustrating the configuration of an apparatus for carrying out the optical information recording and reproducing method of the present invention,
FIG. 2 is a perspective view, and FIG. 3 is a side sectional view. A beam emitted from a light source 11 such as a semiconductor laser is collimated by a collimator lens 12 and divided into three beams by a diffraction grating. These beams are imaged by the objective lens 14 on the optical card ₁ as shown in FIG.
Forms S ₂ and S ₃ . Here, the optical card 1 is moved in the direction of arrow R by a drive means (not shown), and scanned by the beam spot in the direction in which the tracking track and the clock track extend.

The reflected light from beam spots S ₁ , S ₂ , and S ₃ passes through the objective lens again, is reflected by mirror 15 , and is directed by condensing lens 16 to photodetectors 17 , 18 , and 19 placed at the focal plane. are projected respectively. These photodetectors are arranged side by side in the Z direction shown in the figure, as shown in FIG. In addition, the photodetector 17,
Each of the light receiving surfaces 18 and 19 is divided into four parts such as A, B, C, and D.

Next, the operation of recording information on an optical card using the above-mentioned apparatus will be explained with reference to FIG. FIG. 5 shows an enlarged view of the recording surface of the optical card. First, when recording information in the recording area 4 ₁ , spots S ₁ , S ₂ ,
The clock track 2 ₁ , the recording area 4 ₁ and the tracking track 3 ₁ are irradiated with S ₃ , respectively. These spots are scanned in the direction of the arrow a by the movement of the optical card 1 as described above. The reflected light from spot _S1 enters the aforementioned photodetector 17, and a clock signal is reproduced. Further, the reflected light from the spot _S3 enters the photodetector 19, and a tracking signal is detected by the so-called push-pull method. That is,
As shown in FIG. 4, the light receiving surface of the photodetector is divided into A, C and B, D in the y-axis direction corresponding to the tracking length direction. Therefore, when spot _S3 deviates from tracking track ₃₁ , A,
A difference is created in the intensity of light incident on C, B, and D, and a tracking signal is obtained by comparing the signals from these light receiving surfaces. Based on this tracking signal, the spot S ₁ ,
S ₂ and S ₃ are moved together in a direction perpendicular to the scanning direction (b direction) to perform AT. And recording area 4
₁ , the recording pits 5 are accurately recorded along the tracking track ₃₁ by the spot _S2 .

In addition, in the above recording, the photodetector 19 is AT
At the same time, it is controlled so that the spot is accurately connected to the recording surface of the optical card (automatic focusing and below).
It also detects a focusing signal for AF (referred to as AF). This detection principle will be briefly explained with reference to FIG.
In FIG. 6, members common to those in FIG. 3 are denoted by the same reference numerals, and detailed explanations will be omitted. As shown in the figure, the incident light 20 forming the spot _S3 is obliquely incident on the recording surface 21 of the optical card, and the reflected light 22
When the spot is accurately focused on the recording surface, the light beam enters the mirror 15 parallel to the incident light 20 and is guided to the detection surface 23. However, if the recording plane shifts vertically at points 21' and 32'' with respect to the focal point, the reflected light becomes non-parallel to the incident light at points 22' and 22'', respectively, and the irradiation position on the detection surface 23 changes. moves in the y direction. Therefore, by detecting such a change in the light intensity distribution in the y direction as a difference in output between the light receiving surfaces A, B and C, D of the photodetector 19 placed on the detection surface 23, a focusing signal is generated. can get. According to this focusing signal, the objective lens 14 is moved in the optical axis direction to perform AF.

Next, when recording information in the recording area 4 ₂ ,
By moving _the optical _system and _the optical card relative to each other in the Z direction in _FIG . The area 4 ₂ is arranged so as to scan the clock track S ₃ . Then, while the photodetector 17 receives the reflected light from the spot _S1 and performs AT and AF, a clock signal is regenerated from the spot _S3 by the photodetector 19, and information is recorded at the spot _S2 . go.

In this way, in the present invention, two spots are used exclusively for reading the tracking track and the clock track, respectively, and by switching the operations as described above, it is possible to record information in all recording areas. This is what I did.

The operation of processing the information recorded in this way using the same device will be described with reference to FIG.
On the recording surface of the optical card, there are clock tracks 2 ₁ , 2 ₂ and tracking track 3 as shown in FIG.
₁ , . . . information tracks 25 ₁ , 25 ₂ , . . . are formed of recording pit rows. here,
Information track 2 is generated at the aforementioned spots S ₁ , S ₂ , and S ₃ respectively.
5 ₁ , Tracking track 3 ₁ , Information track 2
5 Scan ₂ in the direction of arrow a. Then, while performing AT and AF with the photodetector 18, the photodetector 17
and 19, the information on the information tracks 25 ₁ and 25 ₂ is read out simultaneously. By repeating such operations, information in the entire area of the optical card can be read out at twice the recording speed. In this type of operation, it is not possible to obtain a clock signal from the clock track, but in the case of playback, the clock can be extracted from the signal itself recorded on the information track (so-called self-clock), so there is no practical problem. do not have.

FIG. 8 is a block diagram showing a specific example of a signal processing system from the photodetectors 17, 18, and 19 described above. Here, 51 is a control circuit that controls the opening and closing of switches SW ₁ and SW ₂ , 52, 53, 54,
55, 56, 62, 63, 64, 65, 66, 6
9, 70, 71, 72 are addition amplifiers, 57, 5
8, 67, 68, 73, 74 are subtraction amplifiers, C ₁
~C ₁₁ is a terminal. In FIG. 5, when recording is to be performed in the recording area ₄₁ , the control circuit 51 switches the switch _SW1 to the terminal _C2 side and the switch _SW2 to the terminal _C3 side according to the recording mode. Connected. Therefore, the summing amplifier 53, 5 is connected to the terminal _C1 .
6, 52, the light receiving surfaces A, B of the photodetector 17,
The sum of the outputs of C and D is obtained as the clock signal CL,
The recording by the spot _S2 is controlled as a reference signal through a processing circuit (not shown). _Further , the sum of the outputs of the light-receiving surfaces A and C of the photodetector 19 and B,
The difference from the output sum of D is obtained as a tracking signal AT. This signal AT is supplied from a terminal _C6 to a tracking servo circuit (not shown). Also, the terminal
C ₉ has addition amplifiers 64, 65 and subtraction amplifier 6.
7, the difference between the sum of the outputs of the light-receiving surfaces A and B of the photodetector 19 and the sum of the outputs of C and D is a focusing signal.
Obtained as AF. This signal AF is supplied from terminal _C9 to a focus servo circuit (not shown).

When recording in the recording area ₄₂ , the control circuit 51 connects the switch _SW1 to the terminal _C3 side and the switch _SW2 to the terminal _C7 side. Similarly, the tracking signal AT is connected to terminal _C1 , the clock signal CL is connected to terminal _C6 , and the focusing signal AF is connected to terminal _C4 .
is obtained.

Here, switching by the control circuit 51 is carried out by, for example, when an address signal for each track is recorded in advance in the recording area, this address signal is read out by the light detection switch 18, and the control circuit 51 reads out the address signal based on the address signal. Then, the arrangement of the recording area to be scanned and the tracking track (which side of the recording area the tracking track is on) is determined and carried out.

Next, when reproducing information as shown in _FIG .
Connect switch SW ₂ to terminal C ₇ side on C ₂ side.
The difference between the sum of the outputs of the light receiving surfaces A and C of the photodetector 18 and the sum of the outputs of B and D of the photodetector 18 is obtained as a tracking signal AT at the terminal _C10 through the addition amplifiers 69 and 70 and the subtraction amplifier 73. This signal AT is supplied from a terminal _C10 to a tracking servo circuit (not shown). Furthermore, the difference between the sum of the outputs of the light-receiving surfaces A and B of the photodetector ₁₈ and the sum of the outputs of C and D of the photodetector 18 is obtained as a focusing signal AF through the addition amplifiers 71 and 72 and the subtraction amplifier 74 at the terminal C11. This signal AF
is supplied from terminal _C11 to a focus servo circuit (not shown). And from terminals C ₁ and C ₆ ,
Reproduction signals read out by photodetectors 17 and 19, respectively
RF is taken out.

According to the present invention, no matter in which recording area information is recorded or reproduced, the tracking signal can be detected by the tracking track on either side of the recording area, so accurate AT that is not affected by the clock signal can be performed. It is possible to do this.
Furthermore, since each track has a recording area, it is possible to record and reproduce high-density information. Further, according to the present invention, information can be simultaneously read from two information tracks during reproduction.

The present invention can be applied in various ways other than the embodiments described above. For example, the switching by the control circuit shown in FIG. 8 may be performed by determining whether the track is a tracking track or a clock track using each photodetector, instead of using an address signal. Also,
The method of detecting the tracking signal and the focusing signal is not limited to that of the embodiment, and any known method may be used.

〔Effect of the invention〕

As explained above, the optical information recording and reproducing method of the present invention includes a means for independently detecting tracking signals from three beam spots irradiated onto an optical card, a recording or reproducing mode, and a recording mode during recording. By providing a means for switching the operation of these detection means according to the area, each track on the optical card can be used effectively for recording and playback, and has the effect of enabling highly accurate AT. Furthermore, the information is read with high accuracy during reproduction.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of an optical card used in the optical information recording and reproducing method of the present invention, FIG.
Each figure is a schematic diagram showing the configuration of an apparatus for carrying out the optical information recording and reproducing method of the present invention, FIG. 4 is a diagram showing the arrangement of a photodetector in the apparatus of FIG. 2, and FIG. FIG. 6 is a diagram explaining how information is recorded by the device; FIG. 6 is a diagram explaining the principle of detection of focusing signals in the device shown in FIG. 2; FIG. 7 is a diagram explaining how information is reproduced by the device shown in FIG. 2. 8 is a block diagram showing an example of the configuration of a signal detection circuit in the device shown in FIG. 2, and FIGS. 9A and 9A and 10B and 10A and 10B are diagrams each illustrating an example of a conventional optical card. . 1... Optical card, 11... Light source, 12... Collimator lens, 13... Diffraction grating, 14... Objective lens, 15... Mirror, 16... Condenser lens,
17, 18, 19...photodetector, _S1 , _S2 , _S3 ...
Spot.

Claims (1)

[Scope of Claims] 1. A plurality of tracking tracks, each consisting of a continuous line, which generates a tracking signal, and a plurality of tracking tracks, each consisting of intermittent broken lines, which are arranged alternately with the tracking tracks and generate a clock signal. a clock track, and a recording area for recording information arranged between each of the tracks, and between the two adjacent recording areas, either the tracking track or the clock track is provided. In an optical information recording/reproducing method for a card-shaped recording medium, which records or reproduces information on a card-shaped optical information recording medium characterized in that only one track is arranged, the medium is irradiated with light. (a) one of the second and third beams scans a tracking track to detect a tracking signal; a recording step of recording information by scanning the recording area with the first beam while detecting a clock signal by scanning the clock track with the beam; (b) scanning the tracking track with the first beam; While scanning and detecting a tracking signal, the second and third beams simultaneously reproduce information from recording areas disposed on both sides of the tracking track being scanned by the first beam. 1. A method for optically recording and reproducing information on a card-shaped recording medium, characterized in that recording or reproducing is performed by a reproducing step.