JPS5919251A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To record and reproduce a high-density signal with high stability, by forming two light spots each different in wavelength approximately on the same guide track to use one of these two light spots to record a signal and the other light spot to perform focusing and tracking to the guide track, and to detect a change of the reflected light of the guide track. CONSTITUTION:A semiconductor laser source 61 of a waveform lambda1 generates a light beam l. A condenser lens 62 condenses the light of an LD61 being spreaded, and converts it into parallel beams. An actuator 69 moves an objective lens 68 vertically to the disk surface in response to the surface deflection of the disk and performs a focusing servo action. At the same time, the lens 68 is shifted rectangularly to a guide track 51 on the disk to perform a tracking servo action to the track 51 having eccentricity. In addition, the time axis can be compensated by shifting the lens 68 toward the tangent line of the track 51. The light spots M and L are followed up by the tracking servo action along the same groove. The recording light spot M is irradiated to the area that is already irradiated by the spot L with a small time delay in order to record and reproduce signals. The spot L is used to execute each servo action for focusing and tracking to an optical recording disk and reproduction of signals. While the signals are recorded by the spot M.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a device for optically recording and reproducing signals at high density, and in particular, it relates to a device for optically recording and reproducing signals at high density. The present invention relates to an apparatus for illuminating a disk and recording a signal on a recording medium using at least one beam of light.

Conventional configuration and its problems Laser light is narrowed down to a minute beam diameter of about 1μ, and is irradiated onto a rotating optical recording disk coated with a photosensitive recording material to record and reproduce signals with high density. The device has a recording density of K<9, the memory cost per bit is low, it can be accessed at high speed, recording and playback can be performed without contact between the optical head and the optical recording disk, and the reliability of the optical recording disk and device is improved. It will provide new recording media for the future information society in that it is possible to improve performance, and will be used for recording and reproducing signals, recording and reproducing document signals, recording and reproducing audio signals, recording and reproducing digital data, etc. Application to the front of the device is possible.

FIG. 1 shows an example of the conventional recording/reproducing rule as described above, which is used in a device for cutting the surface of a master video disc for reproduction only.

In Figure 1, 00 is an Ar laser light source for recording, approximately 49
A light beam (a) of 0 nm is generated. (11) is an optical modulator that modulates the intensity of the output light of the Ar laser according to the output signal of the signal source Oz, and produces a light beam (b) toward the optical recording disk.
? :Supply. 0m is a lens that expands the beam diameter of the light, and 04 beam nullifier reflects the original beam (b) toward the objective lens θ5). This light beam is incident on the objective lens 05) with an aperture size of 0υ, and is directed onto the optical recording disk H rotating at a predetermined number of revolutions or speed, with a small diameter (for example, α5 μm in diameter). Form. The light beam on this disk (lυ) is intensity-modulated by the optical modulator (++1), so that signals are recorded in the form of conventionally known bits on the recording thin film deposited or painted on the optical recording disk H. .

071 indicates a disk motor, which rotates the optical recording disk α. α鵠 is a servo circuit that rotates the disk motor. - is a HeNe laser, approximately 630 nm
A light beam (c) of wavelength is generated. This light (c) is A
It is used to reproduce signals recorded by a laser and to control focusing. Beam Nupritsuta (
The light (2) split by 3I) passes through a beam splitter, a diffusing lens (2), and a mirror 04, and is condensed into a minute light beam by an objective lens θ6), which is irradiated onto the optical recording disk 0. This light (reflected light by the disc (Φ) is reflected by the objective lens (16L mirror 0), lens H is
The beam is separated from the optical path of the incident light by the beam nucleator.

The light is irradiated onto the photodetector 1371, and the amount of change in this reflected light is amplified by the preamplifier (c) and becomes a reproduced signal.

On the other hand, one output light (e) of the HeNe laser separated by the beam splitter tie 1) is irradiated onto the optical recording disk θl through a mirror aluminum 2 and an A-object lens 0, and the reflected light is divided into split beams. The light enters the detector, passes through a focus servo circuit, and drives the objective lens drive device to perform a conventional focusing servo. In Japan, the part of the optical head surrounded by the dotted line is the optical recording disc 0.
6) is a radial feed motor that precisely feeds in the radial direction.

In response to this feeding, the optical recording disk θφ is
1/or concentric recording tracks are formed. (4C
I is a servo circuit that drives the radial feed motor.

Figure 2 shows Ar on the optical recording disk θGj in Figure 1.
The relationship between the recording light Q by the laser and the reproduction light (B) by the l1eNe laser is shown. The arrow indicates the rotation direction of the optical recording disk θe. (C4) (C4) (CB) (
C4) shows, for example, uneven recording pits formed on the disk surface by the recording light Q, corresponding to the signal source θ2 in FIG. In order to irradiate the light, the door is separated by a number of 10μ and is placed so as to trace the recording pit (C1) (CC5) (C,).

In this way, the pits recorded with the recording beam ^ are transferred to the reproduction beam 6.
), the signals are sequentially recorded while checking whether the recording by the recording light (g) has been completed completely using the reproducing light (②).

Reproduction of the signal by the reproduction light 6) is carried out while tracking the recorded track by the recording light 2 with the mirror beam 4 in FIG. 1, using a conventionally known tracking search means as required.

The disadvantages of the conventional device shown in FIG. 1 are that, first, the signal recording light does not have a top king reference with respect to the recording disk (it does not have a guide track); The truck hitch is operated by Inamitsu Organization (
In Fig. 1, it is determined only by the degree of feed of the optical head in the radial direction of the disk due to the feed by the diameter μ feed motor. The track hit fluctuates irregularly due to generated vibrations (for example, voice coil vibration, disk motor vibration, etc.), making it difficult to record and reproduce signals at high density with a uniform track hit. In order to perform high-density recording, it is necessary to place the deck on a vibration-proof table, which results in an expensive and hazy device.

On the other hand, in a system in which the recorded area is irradiated with the recording light at a time when the reproduction light is delayed from the recording light as in the configuration shown in Fig. 1, tracking can be performed using the recorded signal. , the pit formation speed of the optical recording material on which the recording pits are formed needs to be extremely fast. In other words, in Figure 1, if the recording light and the reproducing light are separated by 50 μm on the disk, the time it takes for the light to cross a 50 μm area on the disk rotating at 1800 rpm is 167×10 at the outermost circumference of the disk with a diameter of 30 mm. −' seconds. Therefore, for example, the recording pits formed by the thermal energy of the recording light must be in a state where they can be tracked by the reproduction light within 167 μsec (this state varies depending on the recording material and pit formation method). Generally, when uneven pits are formed on a record film, the tracking method and tracking sensitivity differ significantly depending on the depth and shape of the pits.

However, in a system that uses the density reduction of a recording thin film as a recording pit, another method must be considered as a tracking method. That is, in the method shown in FIG. 1, it is necessary to significantly limit the material and thickness of the recording thin film. However, it is completely undesirable to inspect the quality of the signal recording area in advance by irradiating the recording area with the reproduction light temporally and spatially earlier than the recording beam. It is possible.

Purpose of the Invention The present invention is intended to solve the above-mentioned problems, and enables stable high-density recording even when vibrations occur inside or outside the recording/reproducing deck, and moreover, improves the pit formation speed of the optical recording material. The purpose of this is to make it possible to sufficiently reduce the spot interval between the recording light and the reproducing light without being affected. Still, an object of the present invention is to provide an apparatus that can arbitrarily change the irradiation positions of recording light and reproducing light on a recording medium relative to each other.

Structure of the Invention In order to achieve the above object, the present invention uses an optical recording disk having an optically detectable guide track, and creates two or more minute light spots with different wavelengths on the disk at the same time. The aperture optical means is arranged close to each other on the same guide track, and at least one of the plurality of spots is used to detect a track deviation with respect to the guide track, and this detection signal is used to detect the previous several spots on the same guide track. It is configured to track along a track.

Description of examples An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows a radial cross-sectional view of an optical recording disk having guide tracks. Here, an example of a grooved optical recording disk is shown as an example of a guide track. In FIG. 3, a transparent material is used as the disk base material, and a width W
, a groove (51) having a depth d and a track pitch p is formed in a spiral shape or a concentric shape. A recording thin film ridge having a thickness t is formed thereon by vapor deposition or other methods, and a protective layer ridge is provided thereon.

The width W of the groove takes a value smaller than the diameter of the laser beam irradiation light. The depth d of the groove is selected to be a depth at which the diffraction effect of the groove in the far field of reflected light becomes asymmetrical with respect to the optical axis when the center of the groove and the center of the optical axis are deviated from each other. Specifically, if you input the wavelength of the laser beam to be irradiated,
It is set to about d-~-12. Such a groove serves as an optically detectable guide track for the irradiation light of the laser beam. That is, the asymmetry of the far field pattern of the reflected light can be detected and known tracking servo can be applied. Therefore, the irradiating light shown in FIG. 3 can record or reproduce a signal along a specific groove.

FIG. 4 shows an embodiment of the invention using an optical recording disk having optical guide tracks as described in FIG. θ
51) is a semiconductor laser source (hereinafter referred to as LD) with wavelength λ.
, a light beam (a) is generated. Reference numeral 121 is a condensing lens, which condenses the light of the LD (fill) and converts it into parallel light. (65) is an optical element that combines light of different wavelengths, and transmits 9 of the wavelength λ1. , L of wavelength λ2, which will be described later
A light beam of Dω□□□ (has a surface that is anti-8.1 to →).

(661 is a beam splitter, which transmits the optical beam (A) toward the disk. η is a mirror, and the other side is an aperture lens, which narrows the optical beam (A) to a minute optical spot 9, and passes the optical beam (A) toward the optical recording disk. Create a minute spot υ on the top. (6 (2)
is a simplified diagram of the actuator that drives the objective lens 6. This actuator 169) U moves the objective lens holder in a direction perpendicular to the disk surface according to the movement of the disk, thereby performing focusing servo. Further, by moving the objective lens in a direction perpendicular to the guide track on the disk (here, the groove 151 shown in FIG. 3 is shown as an example), tracking servo is performed on the guide track having eccentricity. If desired, a time axis correction can also be carried out by driving the objective lens tangentially to the guide track.

The light beam (c) with a wavelength generated from the LD (b) passes through the condenser lens 6 and is reflected by the optical element (6→), and is combined in the same direction as the light beam 0.Hereafter, the light beam (
c) Beam splitter and mirror T671. A minute light spot 0 is formed on the guide track GIl through the H-relens cormorant. The light spot υYoshimitsu) H is several μ
Each light source and optical component are arranged so that they are formed on the same guide track groove at intervals of m to several lOμ. The reflected light from the disk passes through almost the same optical path as the incident light, and is reflected at the beam splitter (661) in a direction that coincides with the incident optical path. , blocks the light beam (C) with a wavelength of λ. The light beam V) transmitted through the filter plate ff11 is converted into a light beam that is focused by a single lens Q. σ4 is a mirror, and the light beam (C) with wavelength λ is blocked. Half is supplied to the photodetector for focusing error signal detection (741), and about half of the remaining υ is reflected to the photodetector for tracking error signal detection (1υ). It plays the role of an edge and a reflective mirror.

The focus error signal and tracking error signal respectively detected by the photodetector [741 (7fit) are detected by driving an actuator (@) with respect to the optical recording disk and the guide track on the optical recording disk, based on known technology. Performs focusing control and tracking control.

Furthermore, by summing the outputs of the photodetectors (74tlri), the signal component due to the reflected light on the guide track can be regenerated to the terminal (0) by the regenerative amplifier ση.

(Barrel 7 is a reproduction signal processing circuit, and the signal from the recorded area on the guide track (explained in Figure 6) reproduced by the light beam (A) or the signal from the unrecorded area on the groove track (explained in Figure 7) Specifically, in the former case, the signal immediately after recording is played back to detect the quality of the IN raw signal and the occurrence of errors, and in the latter case, the signal is played back immediately before the groove where the signal was recorded. area and pre-inspect for defects such as dropouts on the disc.

The LI1m31 of Wagenjin is used as a light source for signal recording, and H is a laser drive circuit that modulates the intensity of the optical output of the LD131 according to the recording signal input from the terminal, and records the signal on the recording thin film of the groove eave υ. can be recorded.

The configuration shown in FIG. 4 uses a light source with a wavelength λ and a light source with a wavelength λ2 to form a small diameter light beam close to each other on the same guide track of an optical recording disk using the same aperture lens. Focus control, tracking control, and signal regeneration are performed using the light beam (A) with a wavelength of λ2 (A).
) to record the signal.

Fig. 5 (ω(bl), a concrete example of forming a minute light beam by a light beam of wavelength λ1 (A) and a light beam of wavelength λ (C) with an aperture lens I (B) close to the disk. The method is shown in FIG. .The aperture beam narrowed down by the aperture lens 6 tatami of the light beam is on the optical axis γ.
Stop the aperture at the intersection of m and the aperture or the focal plane of the lens 4) M
generate l. γt indicates the optical axis of the light beam (reproduction light), which is aligned with γm and is incident at a small angle θ in the direction of the guide track. Depending on the break, the optical axis γ
A light spot 0 is generated at the intersection of t and the focal plane of the aperture lens 4. If the focal length of the aperture lens It9 is set to 5 front, a light spot of α23° on the guide track can be realized within the allowable aberration due to the optical axis inclination of the aperture lens It9. This inclination θ can be realized by providing a relative positional displacement between the optical axis of the light beam (a) generated from Lαj'+Il in FIG. 4 and the optical axis of the condenser lens.

(in Fig. 5), the aperture lens shown in Fig. (a), the guide track i++, the incident beam to the N9') lens (a) (
) shows a plan view of Arrow X indicates the direction in which the % aperture lens is driven for tracking control with respect to the guide track. As is clear from the figure, the aberration factors for both beams generated by driving the aperture lens in the direction of the arrow X can be considered to be the same, and there is no difference in the quality of the aperture sinupot due to tracking control.

FIGS. 6 and 7 show examples of the positional relationship between the recording light spot Z and the reproduction light spot 0 in the configuration shown in FIG. 4 on the guide track on the disc. In Fig. 6, the arrow indicates the rotational direction of the disc), that is, the direction in which the guide track passes under the light spot 0. (C+) (Cz) (Cs) (C4) indicates the recording spoiler. ) U indicates recording pits formed on the recording thin film.

Optical Spora) (11 (g) is on the same guide track,
The recording thin film is irradiated with a recording spot 0 and then with a reproduction spot 0. Focus control and tracking control for the disc are performed using a optical system (IL).

As shown in Figure 6, 1 when placing each party spot
First, the light beam (a) always emits light of a constant intensity, regardless of whether the signal is being recorded or reproduced. Therefore, focus servo and tracking servo can be performed stably during signal recording and reproduction. This tracking servo causes the optical spoiler 1ll (Ll) to follow along the same groove.Secondly, since signals are recorded and reproduced while always tracking the desired groove with the optical beam V, vibrations outside the recording and reproducing apparatus can be avoided. High-density symbols can be recorded and reproduced stably without disturbing the pitch of the recording track due to vibrations inside the device. Thirdly, the pits recorded by the recording light spot 9 using the light beam (/-) can be checked stably with a slight time delay, so it is possible to check whether the signal was recorded accurately and whether the recording power is appropriate. can be checked. For example, if the recording quality is not appropriate, try changing the recording conditions.
Alternatively, the signal can be recorded again at another location on the disc.

FIG. 7 shows the arrangement of light spots in which a recording light spot (b) is irradiated with a slight time delay onto a region irradiated with light spot υ to record and reproduce signals. The focus camera, tracking servo and signal reproduction for the optical recording disk are performed by an optical spora (L), and signal recording is performed by an optical spot (2).

Even in this arrangement, signals can be recorded and reproduced along the guide track, and stable and high-density signals can be recorded and reproduced.

Furthermore, it is possible to scan and inspect the unrecorded portion of the guide track where a signal is to be recorded by using the optical spot υ prior to recording the signal. i.e. to the part where the signal is to be recorded.

If there is a large dropout, or if the guiding track itself is defective.

It is now possible to detect this in advance and interrupt recording, and if an interruption occurs, the signal is recorded in a new recording area on the disk, reducing the time required to re-record the signal. It is possible to shorten the time and maintain the quality of the recording/reproducing signal at a good level at all times. Also, 1lli1 of the light spot that combines Fig. 6 and Fig. 7.
2 positions (three self-devices including a reproducing light spot, a recording spot, and a reproducing spoiler 1 to 1 along the guide track) can be performed.

Although an optical recording disk having a rectangular groove as a guide track has been described, groove shapes other than rectangular can also be used. As a guide track, signal areas for servos with different frequencies are placed on both sides of the signal recording area.
It is also possible to record and reproduce signals along with this servo signal.

In addition, in the arrangement of the light spots shown in Figures 6 and 7, the light source that generates the optical light source for recording (the door in Figure 4) is designed to emit light only when recording signals, and not to emit light at other times. By controlling the recording and reproducing system shown in FIG. 4, mutual interference between the two light sources can be eliminated and a more stable system can be achieved.

Further, in the configuration of FIG. 4, LDIII with wavelength λ1.

Although the wavelength ^, Ll] 831 is shown individually, as shown in FIG. The same effect can be obtained by using f steam.

Effects of the Invention As described above, according to the present invention, two light spots of different wavelengths are formed close to each other on the same guide track of an optical recording disk having guide tracks, and a signal is transmitted using one of the light spots. By recording and using the other light spot to focus on the guide track, tracking, and detecting changes in reflected light from the guide track, it is possible to record and reproduce more stable and higher-density signals than the conventional system shown in Figure 1. Therefore, it is possible to obtain a synutem which is capable of recording and reproducing signals of good quality.

The tracking signal in the present invention is obtained from a guide track as shown in FIGS. 3 and 6, and the tracking signal is obtained from recorded pits with unevenness as shown in FIG. is essentially different. Therefore, the recording pits of the present invention shown in FIG. 6 may be pits with a flat density structure in which only reflected light and transmittance change.

It is characterized in that it may be a recording pit with a phase structure having irregularities of arbitrary depth.

[Brief explanation of the drawing]

Figure 1 shows a conventional optical recording and reproducing system using a two-wavelength light source! Fig. 2 is a diagram showing an example of an optical recording disk and recording signals in the apparatus shown in Fig. 1, and Fig. 3 is an enlarged cross-sectional view showing an example of an optical recording disk having a % groove track as a guide track. 4 is a block diagram showing an embodiment of the present invention using an optical recording disk having a guide track, and FIG.
Figures (a) and (b) show how light enters the aperture lens when two light beams are placed close to each other on the same guide track. Figure 8 is a diagram showing how to arrange the light spots in Figure 4.
It is a figure which shows the structural example of another light source used in the structure of a figure. +511... Groove (guide track), extension 11 F, (3
)...Semiconductor laser, (6 uniform...Optical element, ((
g)...Beam Nupris, ■...Aperture lens, (
Function...Actuator, ffl+...Filter plate, Point...Photodetector for detecting focus error signal, +15
1...Photodetector for tracking error signal detection, (M+
...Recording light spot, 0...Reproducing light spot Fig. 1 Fig. 8 Fig. 1 d Fig. 4 Fig. S (li (Saλ) Fig. 2 Fig. 7 Fig.

Claims (1)

[Claims] L An optical recording disk having an optically detectable guide track, and two or two tracks of different wavelengths on this disk.
means for arranging more than one minute light spot in close proximity to each other on the same guide track using the same aperture optical means; means for detecting a track deviation with respect to the guide track using at least one light spot of the plurality of spots; An optical recording/reproducing apparatus comprising means for controlling tracking of the plurality of spots along the same guide track based on a track deviation detection signal. 2. The optical recording and reproducing apparatus according to the scope of the patent application, item 1, which is configured such that at least one of a plurality of spots arranged close to each other on the same guide track records a signal. (a) An optical % formula according to claim 1, which is located on the same guide track and configured such that the reproduction light scans the recording area after the recording light scans.9. 2. The optical recording/reproducing apparatus according to claim 1, wherein the recording light scans an area after being scanned by the reproduction light to record and reproduce signals. Hill: The recording light source has a means for emitting light only for signal recording.The optical type % type %G according to claim 2, wherein the recording light source has a means for emitting light only for signal recording. The optical recording and reproducing apparatus according to claim 3, further comprising means for checking quality and recorded content. 7. The optical recording according to claim 4, which has means for reproducing the signal-unrecorded portion of the guide track with reproduction light and inspecting its quality, and having means for interrupting recording when an abnormality is detected. playback device.