JPS58179944A - Method and device for recording and reproduction of signal - Google Patents

Abstract

PURPOSE:To realize a compact structure and high recording density for a signal recorder/reproducer, by using a cylindrical recording medium. CONSTITUTION:A cylindrical recording mediumm 4(1) is turned to keep a focused state of a condenser lens 7(2) which is provided via a ball caster 5 having a revolving contact with the surface of the medium 4(1) and a plate 6. Then the signal is recorded by the condensed microspots and via a polarizer 3. Owing to use of the cylindrical recording medium 4(1), a compact structure is attained for a signal recorder/reproducer along with high recording density.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-density information recording method, and more specifically to a method for recording high-definition image information on a small recording medium, which is applied to file memory and frame memory of video signals. The present invention relates to a method and an apparatus for carrying out the method.

In recent years, research into high-density information recording and reproducing devices such as video discs has been active.

Currently, as such a high-density recording and reproducing method, an optical method is very advantageous in terms of its high recording density. Furthermore, in the near future, it is inevitable that a memory system that allows users to repeatedly record and reproduce information using an optical method will be integrated into one product.

First of all, it is essential for such a recording device for consumer users to be compact. In order to achieve compactness, a recording/reproducing method is required that allows the recording medium to be small and has a high recording density.

Conventional recording media are often shaped like disks, but in this case, the recording and playback method of one frame per disk lWR, as seen in video disks, requires higher recording density toward the inner circumference. . In a video disk, one frame of image is recorded every round in a recording area of 120 to 3005 m in diameter, but this is currently the maximum possible, and it is impossible to make the disk any smaller. Therefore, in order to realize a compact signal recording and reproducing device, it is necessary to consider a new signal set and reproducing method that also takes into account the shape of the recording medium.

SUMMARY OF THE INVENTION In view of the above-mentioned requirements, an object of the present invention is to provide a signal recording/reproducing method and an apparatus thereof that have a compact configuration and are capable of recording and reproducing at a high recording density.

The present invention achieves the above object by making the recording medium cylindrical and performing recording and reproduction with a light beam scanned in the direction of the rotation axis of the recording medium.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the signal recording and reproducing method of the present invention.

In FIG. 1, reference numeral 1 denotes a recording medium whose surface is coated with a recording material such as a magneto-optical material, and is driven to rotate. Signal recording is performed using a minute spot focused on the surface by a condensing lens 2. 3 is a beam deflector for scanning the spot up and down in the figure.

Figure 2 shows that in the present invention, 17
An example of a recording and reproducing method when recording TvIbI image signals for one frame is shown below. Such an example is applied to still video, etc.

Here, the cylindrical recording medium 1 rotates at a constant rotation speed of 180 rpm when recording an NTSO image signal. This method of rotating the recording medium at a rotation speed matching the number of 7 frames per second and recording one frame H image for each rotation makes it easy to trace the signal track when playing back still images. This is advantageous in certain respects.

The recording tracks are formed by repeatedly scanning the spots during the rotation of the recording medium 101 so as to be lined up as shown at A1 in FIG. Assuming that one scan of the spot records the IH portion of the image signal, that is, one horizontal scanning line, in the NTFjO method, 525 scans are performed for each recording medium 1, that is, the signal track indicated by A1 is recorded on the surface of the cylindrical recording medium. In total, 525 lines will be formed.

When the diameter of the cylinder is R, the length of the surface 1Pi1 is πR. For example, if the diameter of the cylinder is 2006 mm, one revolution of the recording surface is approximately 6XOsm. Therefore, the interval between the recording tracks indicated by Al in FIG. 2 is 120 μm.

From current video discs, it is thought that the light spot can be narrowed down to a diameter of about 1 μm using a condensing lens, and the signal track pitch can be narrowed down to about 2 μm.

Therefore, as shown in Figure 2, between the signal tracks of A 1, A 2
, A 3, ---- In this example, by recording other frame images such as
A frame image can be recorded. Furthermore, even when recording a high-quality TV image having 1125 scanning lines in one frame, it is possible to record about 28 7-lem images per revolution using a cylindrical recording medium with a diameter of about 20 meters.

Here, the length of the signal track is such that if the spot diameter is 1 μm, it is possible to record the IH image signal in 1 to 2 days, and it is possible to record the IH image signal on a small recording medium, in this example, a recording medium with a diameter of 200 mm and a length of 2 mm. It is possible to record as many as 60 TV7 frame images. Of course, the number of recording frames per recording medium can be increased by increasing the diameter of the cylinder or increasing the length of the cylinder as shown in FIG. 1, and recording over several layers.

An embodiment in which a TV image signal is reproduced in one line using the present invention has been described above.Next, individual techniques for realizing this embodiment will be explained.

First, it is desirable to use a recording medium that can be repeatedly recorded and reproduced. In this sense, the aforementioned magneto-optical media are effective, and recording media are created by forming such magneto-optical media on the surface of a cylindrical substrate made of glass, metal, polymeric material, etc. by vapor deposition, sputtering, etc. can. As is well known, recording with a magneto-optical material utilizes the rotation of a preferential optical surface due to a magneto-optical effect such as the Curab effect on the magneto-optical material, which is magnetized in a fixed direction by photothermal energy.

Second, there is a diameter of 1μ on the recording medium! Since the light beam is narrowed down to about +1, the focusing of the lens becomes intermittent.

A well-known 7-ocusing control method combines an astigmatism optical system and a 4-split detector, as used in video discs. Although such known methods can be adopted in the recording and reproducing method of the present invention,
Here, in the present invention, in a compact structure A [3, Figure 3), the number is a cylindrical recording medium. A plate 6 is provided via a pole caster 5 that rotates in contact with the surface of the recording medium 4, and a condensing renderer is provided approximately at the center of the plate 6. The distance between the renderer and the medium 4 is set to the focal position of the lens 1 (so-called working distance). A plate 6 on which a lens 7 is provided is supported by a movable table 9 via a spring 8, and is pressed against the recording medium by the spring pressure of the spring 8.

With the above configuration, even if the recording medium performs eccentric rotation, the renderer and the recording medium 4 always maintain a focused state, and a complicated focus control means can be omitted. Here, the support stand 9 can be moved in the direction of the rotation axis of the recording medium along the guide holder 10 by means of a feed screw 11 as shown in FIG. Further, by mounting an optical system other than a condenser lens (not shown in this figure) including a light source on the support base 9, it is possible to construct a stable optical system even when the support base 9 is moved.

The light deflection means will be described in FIG. In this embodiment, since the Tv image signal IH is recorded in one scan as described above, the repetition frequency is 1a75 kHz in the MTEjO method.
light deflection must be performed.

Further, when recording a high-quality TV#i image signal, even higher-speed repetitive scanning is required. Although a galvanometer mirror is known as a general optical deflection means, it cannot be used in this embodiment because of its low scanning reversal frequency.

Therefore, an optical deflection element that can be fully adapted to this embodiment is shown in FIG.
1331, patent application 1986-12939, patent application 1982-14
989, patent application No. 55-56080, patent application No. 55-416
082, etc., and the detailed structure and functions are described in the above proposal, so a brief explanation will be given here.

The deflection element in FIG. 4 is a piezoelectric crystal substrate (for example, LiNb
0. ) A waveguide layer 21 having a higher refractive index than the substrate 20 on which T1 or the like is diffused, and a tooth-like electrode (more T) 22 that generates a surface acoustic wave in this waveguide layer 21. This shows a typical example of wetting, and for example, a waveguide may be formed by placing a piezoelectric material such as ZnO on a glass substrate or the like. A light beam 24 such as a laser beam is transmitted to such a deflection cable f through a coupler 23 such as a prism.
to guide the wave. Here, the coupler 23 is a grating provided directly on the waveguide layer, or an end surface 25 of the waveguide.
One type of bad end 7-ear system that guides light directly from
In addition, the present applicant has filed Japanese Patent Application No. 56-27750, Japanese Patent Application No. 56-27750,
A coupling method using a diffraction grating structure proposed in No. 87187 may be adopted.

The guided light is diffracted by a surface acoustic wave emitted in accordance with an electric signal applied to the comb tooth-shaped electrode 22. The angle θ between the diffracted light 26 and the non-diffracted light 2 is e = slm-'(-"-) (1)2
n? is given by Here, λ is the wavelength of the incident light 24 in air, f is the frequency of the electric signal applied to the comb tooth-shaped electrode 22,
V is the velocity of the surface acoustic wave, and n is the refractive index of the waveguide 21. Since - is a function of the frequency f, the light can be scanned by applying a signal (charbut signal) whose frequency increases moment by moment to the comb tooth-shaped electrode 22.

Also, here the speed of repetition of deflection is the speed of elastic waves pI!
, V and light @W, the repetition frequency 1 is ■ 'I! It is given by J = −(2). For example, if the width of the guided light beam is 6 cm, the elastic wave LiNb0. The speed within is approximately &5XIO'W
/sea, so it is 1.chi.580 kHz, and the response is 2 to 3 orders of magnitude compared to a normal galvano mirror, which is sufficiently applicable to this embodiment.

Among the optical deflection elements as described above, examples that are used in the signal recording/reproducing apparatus of the present invention are shown in FIGS. 6 and 6.

In FIG. 5, it is preferable that the luminous flux 2 is emitted from a semiconductor laser capable of current modulation, which is advantageous for compactness. The light beam guided by the coupler 29 is deflected by a surface acoustic wave 31 caused by a comb tooth electrode (T) 30, and is radiated into the air by an output coupler 32. This light beam is condensed into a minute spot on the recording medium by a condenser lens 33 to record a signal.

FIG. 6 shows another example in which a thin film lens is provided on the waveguide. Such a thin film lens was also proposed by the present applicant in Japanese Patent Application No. 56-82680. 2 Here, the light beam is focused near the end face of the waveguide by the thin film lens 34 to form a spot. The advantage of such an example is that the light deflection and light collection can be formed as one solid-state element.

Fourth, a method for recording and reproducing different frame images between tracks will be described.

A tack signal of one pulse per rotation as shown in FIG. 7(a) is detected from the motor that rotates the recording medium. Next, from this tack signal, pulse signals of the same number as the number of tracks determined by the number of frames to be recorded are divided as shown in Figure 7 to create a pulse signal. Assume now that one frame image is to be recorded. During recording, the optical deflector is first driven in synchronization with the 1st, N+1st, 2N+1st, and 3N+1st °''-° of the frequency-divided signals using the motor tack signal as a reference, and then the signal is recorded. 2#th frame Wj image #i2nd,
Recording is performed in synchronization with the frequency-divided signals of N+2nd, 2nd shoulder+2nd 13M+2nd, and N frame images are recorded in one revolution. Next, as shown in FIG. 1, by relatively moving the recording medium and the light beam scanning means, similar recording is performed in another area. During this recording, the spring address number, which is the number of the 7th frame image, is recorded at the beginning of each track.

During playback, as shown in Figure 8, the recording medium is rotated with a minute spot 35 placed at the beginning of the track 36, the address number recorded at that position is read out, and the address number that matches the number of the frame image to be played is read out. At the same time, the optical deflector is driven to scan the track. By recording and reproducing as in this example, searching and reading with short access time is possible.

Also, another method of recording and reproducing different frame images on a recording medium will be explained. To simplify the explanation, recording of a frame image in the #1 NTSO method will be taken as an example.

FIG. 9 is a diagram showing tracks recorded on the side surface of a cylindrical recording medium arranged circumferentially for explanation in the recording/reproducing method of the present invention. Here, the IH portion of the frame image signal is recorded on one track, and the first H signal is
1. Set the second to 42------ and the last ■ of the frame.
The signal, that is, the 525th H signal is indicated by A325. Assuming that the angular pitch between H signals is θp and the number of frames recorded in one round is 1, 525 H signals are recorded in one round as follows.

At this time, the first H signal is recorded from the A325 signal track and before the Jl&l signal track. At this time, if the recording medium is continuously rotated at I!, N frame images will be sequentially displayed.
It can be recorded with a trunk pitch of I interval. This method is advantageous when recording or reproducing frame images continuously.

In the above example, the IH flaw signal is recorded on one signal track, but the IH flaw signal can also be divided into two tracks and recorded. Next, the recording and reproducing method will be described.

When recording signals on a recording medium by scanning the original beam,
After completing one scan, a short return time is required until the next scan. In the case of a continuous image signal, signal loss occurs during recording or reproduction due to the return time of the C light beam.

To solve this problem, a memory that stores 1H worth of image signals is used. Now, it is assumed that the lHo1ill image signal is divided into summer tracks, and the return time is assumed to be t8·C.

The scanning frequency of the light beam is 1a f5XII klliz (5
). The signal is then stored in the -HIH memory.

Then, sweep it out intermittently as follows. That is, time sweep is performed, time is stopped, and then the time sweep shown in (6) above is repeated N times.

When this operation is performed for the TV double signal 1H time, that is, 635μ, the frequency of the original 'rv signal is raised and swept out by the unrecordable amount of the return time Mt, and the frequency is as follows. If the signal is sent continuously, two I
As an example, you can use the H memory to record signals swept out of one memory, store them in the other memory while you are doing so, and then switch between these two memories and perform the same operation one after another. , if the IH flaw signal is divided into four parts and recorded, and the return time is 3 μgec, the scanning frequency of the light beam is Fi6.
3 kHz, signal Fil & 8754 sea sweep out, 3 fi sea stop, 12-875 fi sea
Sweep it out and repeat the process ----- to record it on the recording medium.

The frequency Fi of this recorded signal is 123 times higher.

During reproduction, the same beam scanning as in recording is performed, and the read signals are intermittently stored in the IH memory. That is, in this example, 12h875β8・C memory, 3μsec stop, 12L
875μ8・C recording %'-----Repeat the memo IJ Th et al. After the lH signal is memorized,
Sweep out at the original TV signal rate. In this way,
Recording and reproduction can be performed by dividing the IH scratch signal into tracks.

Although the embodiment of recording and reproducing TVI image signals using the present invention and the individual techniques for realizing this embodiment have been described above, the present invention is not limited to such TVI image signals. It can be used in any case where an information signal is recorded on or reproduced from a recording medium.

FIG. 10 is a perspective view showing an example in which the present invention is applied to still and video processing. Here, an image of the subject is captured by an image sensor such as a 3F 1JOD, and the image signal is converted into a signal to be recorded on a cylindrical recording medium 39 by an electrical conversion circuit 38. The recording medium 39 can be removed using a knob 40 like a silver halide film cartridge. The signal from the electric processing circuit 38 is sent to a semiconductor laser driver 41 to drive a semiconductor laser 42 . Recording medium 39#i motor 43&C
The light beam emitted from the semiconductor laser 42 is scanned by a light deflector as shown in FIG. 3, which is attached to a support base 45, and a frame image is recorded as shown in FIG. 1. do. After recording, the recording medium is removed from the camera body and the signal is reproduced using a separate reproduction device.

As explained above, the signal recording and reproducing method of the present invention includes:
By using a cylindrical recording medium, the signal recording and reproducing apparatus can be constructed more compactly than in the past.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the recording and reproducing method of the present invention, FIG. 2 is a diagram explaining an example of the method of recording multi-frame images in the present invention, and FIG. In the focus control mechanism that can be used in the invention, the husband k (A) is a perspective view, (E
) indicates a cross-sectional view. Figures 4, 5 and 6 are diagrams showing control signals during recording used in the present invention, Figure 8 is a diagram showing the positional relationship of recording tracks; The figure is a diagram illustrating another example of the method for recording multi-frame images in the present invention, and Fig. 1O shows the present invention applied to a still video camera 1 ------- Cylindrical recording medium 2 - -------- Unifocal lens 3 ----------- Unifocal deflector Applicant Canon Co., Ltd.

Claims (3)

[Claims] (1) In a signal recording and reproducing method in which a signal is recorded on a recording medium using a light beam and the signal recorded on the recording medium is reproduced, the recording medium has a cylindrical shape, and the recording medium is rotated to A signal recording/reproducing method in which recording or reproduction is performed by scanning a beam in the direction of the rotation axis of the recording body. (2) a means for rotating a cylindrical recording medium, a light beam for recording a signal on the recording medium or reproducing a signal recorded on the recording medium, and a means for rotating the recording medium with the light beam; A signal recording and reproducing device comprising means for scanning in a direction. (3) The hand 19G scanning the light beam, the recording 1
Signal recording device-0 according to claim 2^l, which moves four times based on a tack signal obtained from a means for rotating the body.